50574468 Cymcap Manual

February 2007

CYMCAP 4.6 for Windows

Copyright CYME International T&D Inc.

All Rights Reserved

This publication, or parts thereof, may not be reproduced in any form, by any method, for any purpose. CYME International T&D makes no warranty, either expressed or implied, including but not limited to any implied warranties of merchantability or fitness for a particular purpose, regarding these materials and makes such materials available solely on an "as-is" basis. In no event shall CYME International T&D be liable to anyone for special, collateral, incidental, or consequential damages in connection with or arising out of purchase or use of these materials. The sole and exclusive liability to CYME International T&D, regardless of the form of action, shall not exceed the purchase price of the materials described herein. CYME International T&D reserves the right to revise and improve its products as it sees fit. This publication describes the state of this product at the time of its publication, and may not reflect the product at all times in the future. The software described in this document is furnished under a license agreement. CYME International T&D Inc. 67 South Bedford Street, Suite 201 East Burlington, MA 01803-5177 1-800-361-3627 (781) 229-0269 FAX: (781) 229-2336 International and Canada: 1485 Roberval, Suite 104 St. Bruno QC J3V 3P8 Canada (450) 461-3655 Fax: (450) 461-0966

Internet : http://www.cyme.com E-mail : [email protected]

Windows 98 and Windows NT, 2000 & XP are registered trademarks of Microsoft. Autocad is a trademark of Autodesk Inc.

NOTICE The computer programs described in this manual were developed jointly by CYME International T&D Inc., Ontario Hydro and McMaster University under the auspices of the Canadian Electricity Association (CEA). Neither CYME International T&D, Ontario Hydro, McMaster University, CEA, nor any person acting on their behalf: (a) makes any warranty, express or implied of any kind with regard to the use of the computer programs, the documentation and any information, method or process disclosed therein, or that such use may not infringe privately owned rights; or (b) assumes any liabilities with regard to the use of, or damages resulting from the use of the programs or other information contained in this document. The software described in this document is furnished under a license agreement.

CYMCAP for Windows

TABLE OF CONTENTS I

Table of Contents

Chapter 1 Getting Started ..............................................................................1 1.1 Overview of CYMCAP ..................................................................................1 1.2 Software and hardware requirements ..........................................................2 1.3 Installing CYMCAP for Windows ..................................................................2

1.3.1 Installation steps From a CD..........................................................2 1.3.2 Installation steps From a downloaded file......................................3 1.3.3 Setting up the protection key.............................................................3 1.3.4 Windows Settings..............................................................................3

1.4 The contents of CYMCAP ............................................................................4 1.4.1 CYMCAP Graphical User Interface...................................................5 1.4.2 The CYMCAP libraries and utilities an overview............................5 1.4.3 Populating the CYMCAP libraries .....................................................7

1.5 What you should know about running studies with CYMCAP......................8

Chapter 2 The Cable Library ..........................................................................9 2.1 Introduction ...................................................................................................9

2.1.1 Cable data in studies.........................................................................9 2.2 Cable library Navigator window..................................................................10

2.2.1 Cable library window commands ....................................................11 2.2.2 Cable library pop-up menu..............................................................12

2.3 Cable design data window elements..........................................................13 2.4 Steps to create a new cable .......................................................................16 2.5 Cable components, materials and construction .........................................17

2.5.1 Conductor data................................................................................18 2.5.2 Conductor shield data .....................................................................21 2.5.3 Insulation data .................................................................................22 2.5.4 Insulation screen .............................................................................23 2.5.5 Sheath .............................................................................................24 2.5.6 Sheath Reinforcing Material............................................................24 2.5.7 Skid wires (for pipe type cables only) .............................................25 2.5.8 Concentric neutral wires..................................................................25 2.5.9 Armour/Reinforcing tape .................................................................26 2.5.10 Armour Bedding/Armour Serving ....................................................27 2.5.11 Jacket, oversheath and pipe coating material.................................28

2.6 Creating a new cable - Example.................................................................29 2.7 Useful considerations .................................................................................35

2.7.1 Cable layers ....................................................................................35 2.7.2 Particular modeling..........................................................................35 2.7.3 SL-type cables.................................................................................36 2.7.4 Custom materials and thermal capacitances ..................................36

2.8 Filter Editor .................................................................................................37

Chapter 3 The Ductbank Library..................................................................39 3.1 Introduction .................................................................................................39 3.2 Ductbank library management....................................................................39

3.2.1 Creating a new duct bank. An illustrative example. ........................40

Chapter 4 Load-Curves/Heat Source Curves and Shape Libraries ..........43 4.1 Introduction .................................................................................................43

4.1.1 Curves and Shapes.........................................................................43 4.2 Shape Library management .......................................................................44

CYMCAP for Windows

II TABLE OF CONTENTS

4.2.1 Creating a new shape An Illustrative example.............................45 4.2.2 Shifting a shape An illustrative example ......................................47

4.3 Load and Heat Source Libraries Management...........................................49 4.3.1 Expanding and collapsing the curves .............................................50 4.3.2 Curves libraries command buttons .................................................52 4.3.3 Create a Load Curve using existing shapes An illustrative example ......................................................................................................52 4.3.4 Load Curve from field-recorded data ..............................................57

Chapter 5 Steady State Thermal Analysis ..................................................61 5.1 General .......................................................................................................61 5.2 Methodology and computational standards................................................61 5.3 Accuracy of CYMCAP and References......................................................64

5.3.1 References ......................................................................................66 5.4 Studies and executions ..............................................................................66 5.5 Library of studies and executions ...............................................................67

5.5.1 Study library pop-up menu ..............................................................68 5.6 Creating a study..........................................................................................72 5.7 Analysis options..........................................................................................74 5.8 Steady state analysis..................................................................................75

5.8.1 General data for the installation ......................................................76 5.8.2 Cable Installation data.....................................................................82 5.8.3 Specific cable installation data ........................................................83

5.9 Cable Library data and executions .............................................................89 5.10 Steady state thermal analysis, Example 1: Cables in a duct bank.............90

5.10.1 Defining a new study and a new execution.....................................91 5.10.2 Setting the steady state analysis solution Option ...........................92 5.10.3 Execution speed bar and associated command buttons ................93 5.10.4 Defining standard and/or non-standard duct banks........................95 5.10.5 Importing a duct bank from the Library ...........................................96 5.10.6 Defining the general installation data and setup .............................97 5.10.7 Defining the cable installation data .................................................98 5.10.8 Rearranging the cables in the proper ducts ..................................100

5.11 A study case for dissimilar directly buried cables.....................................101 5.11.1 Define a new execution using an existing one as template ..........101 5.11.2 Modify the solution option from the CYMCAP menu.....................102 5.11.3 Enter a group of cables using absolute coordinates.....................103 5.11.4 Enter a trefoil formation using relative coordinates.......................103 5.11.5 Specify a fixed ampacity circuit...................................................105 5.11.6 Convergence and the Selection of Reference Circuit...................106 5.11.7 Specify a heat source included in the installation .........................107

5.12 Specific installation data ...........................................................................108 5.13 Results Reporting .....................................................................................108 5.14 Steady-state results labels .......................................................................109

5.14.1 View/hide labels ............................................................................110 5.14.2 Label grid editor.............................................................................111 5.14.3 Select/move/align labels ...............................................................111 5.14.4 Change the connection line between the cable and its associated label 113 5.14.5 Change the properties of a label ...................................................113 5.14.6 Reset all labels to their default positions.......................................114 5.14.7 Keep all labels positions permanently...........................................115

5.15 Viewing the graphical ampacity reports by mouse selection....................116 5.16 Tabular Reports ........................................................................................118 5.17 MS Excel (Final) Report............................................................................118

5.17.1 The Electrical Tab..........................................................................121

CYMCAP for Windows

TABLE OF CONTENTS III

5.18 Opening more than one executions simultaneously ................................124 5.19 Working with more than one executions simultaneously .........................127

5.19.1 Submitting more than one executions simultaneously..................127

Chapter 6 Transient Analysis.....................................................................129 6.1 General .....................................................................................................129 6.2 Preliminary considerations .......................................................................129 6.3 Transient analysis options ........................................................................130

6.3.1 Solve for Ampacity Given Time and Temperature ........................130 6.3.2 Solve for Temperature given Time and Ampacity.........................131 6.3.3 Solve for Time given Ampacity and Temperature.........................132 6.3.4 Ampacity as a function of Temperature ........................................133 6.3.5 Ampacity as a function of Time .....................................................133 6.3.6 Temperature as a function of Time ...............................................134

6.4 How to proceed for a transient analysis ...................................................135 6.5 Informing CYMCAP that a transient analysis is to be performed .............135 6.6 Example and Illustrations .........................................................................136

6.6.1 Case description and illustrations .................................................136 6.6.2 Specify the transient analysis option.............................................137 6.6.3 Specify the data for the transient analysis option .........................137 6.6.4 Assign Loads to Cables ................................................................138 6.6.5 Submit the simulation ....................................................................139 6.6.6 Generate the reports .....................................................................140 6.6.7 Change the color of the curves for the transient reports...............142 6.6.8 Trace the transients results with the mouse .................................142

Chapter 7 Approximate Temperature Field...............................................145 7.1 Introduction ...............................................................................................145 7.2 Scopes and Limitations ............................................................................146 7.3 Customizing the Isotherms .......................................................................147 7.4 Automatic Design of Backfills/Duct Banks................................................149

Chapter 8 The Sensitivity Analysis Option of CYMCAP ..........................153 Chapter 9 The CYMCAP Menu ...................................................................157

9.1 Overview of the CYMCAP Menu ..............................................................157 9.2 The Files menu .........................................................................................157 9.3 The Windows menu..................................................................................158 9.4 The CYMCAP menu for opened executions ............................................158 9.5 The File menu - Execution........................................................................158 9.6 The Edit menu - Execution .......................................................................159 9.7 The View menu - Execution......................................................................159 9.8 The Options menu - Execution .................................................................160

9.8.1 Simulation control parameters ......................................................162 9.9 Designate the Unit System for the session ..............................................163 9.10 Designate the AC system frequency for the session ...............................163 9.11 Designate AC conductor resistance values..............................................163

Chapter 10 CYMCAP Utilities.......................................................................165 10.1 Introduction ...............................................................................................165 10.2 Designate the working directory for CYMCAP .........................................165 10.3 Backup the contents of the Working directory to another directory .........166 10.4 Append a database to another database .................................................166 10.5 Restore from floppy disk to a directory on the hard-disk..........................167 10.6 Tag specific items from the Libraries........................................................167 10.7 Copy selected items to a given data base................................................168

CYMCAP for Windows

IV TABLE OF CONTENTS

Chapter 11 Defaults for Various Types of Cables ......................................171 11.1 Defaults Overview..................................................................................171 11.2 Concentric neutral cables .........................................................................171 11.3 Extruded dielectric cables.........................................................................173 11.4 Low pressure oil filled cables (Type 3) .....................................................174 11.5 High pressure oil (gas) filled cables .........................................................175 11.6 Sheath related defaults.............................................................................177 11.7 Armour related defaults ............................................................................178

11.7.1 Three core cables..........................................................................178

CYMCAP for Windows

CHAPTER 1 - GETTING STARTED 1

Chapter 1 Getting Started

1.1 Overview of CYMCAP

The determination of the maximum current that a cable can sustain without deterioration of any of its electrical and/or mechanical properties has always been of prime interest to engineers and constitutes an important design parameter for both system planning and operations.

Accurate ampacity studies help maximizing the benefits from the considerable capital investment associated with cable installations. Also they help to increase system reliability and the proper utilization of the installed equipment.

CYMCAP is a Windows-based software designed to perform thermal analyses. It addresses both steady state and transient thermal cable rating. These thermal analyses pertain to temperature rise and/or ampacity calculations using the analytical techniques described by Neher-McGrath and the IEC 287 and IEC 853 International standards. More details on the implemented methods and the validation made to CYMCAP can be found in section 5.2 Methodology and computational standards.

CYMCAP features four additional optional analysis modules, the capabilities of which are covered in a separate manual. The modules are:

y The CYMCAP/OPT Duct Bank Optimizer to determine the placement of several circuits within a duct bank so that certain optimal criteria are fulfilled.

y The Multiple Duct Banks module (MDB) to determine the steady state ampacity of cables when they are placed in several duct banks and/or backfills in the same installation.

y The CYMCAP/SCR Short Circuit Cable Rating (SCR) module dedicated to the calculation of the adiabatic and non-adiabatic short-circuit ratings.

y The Cables in Tunnels Module to determine the temperature, steady state, cyclic and transient ampacity of cables installed in unventilated tunnels.

y The Magnetic Fields Module. Once an ampacity or a temperature run has been performed, the module computes the magnetic flux density at any point on or above the ground for an underground cable installation using the current computed or specified in the steady state simulation.

CYMCAP for Windows

2 CHAPTER 1- GETTING STARTED

1.2 Software and hardware requirements

CYMCAP is a 32-bit application, runs on IBM PC or compatible personal computers and can be used with Windows NT and Windows XP operating systems.

The minimum hardware requirements are: A Pentium-based computer 32 MB RAM 10 MB free memory on the hard disk A Microsoft mouse or equivalent A color monitor with Super VGA and a graphic card supporting 256 colors or more Any printer or plotter supported by Windows

1.3 Installing CYMCAP for Windows

CYMCAP can be installed from a CD or downloaded from our web site at www.cyme.com/newversion.htm. In both cases, a password is needed for the application to be unpacked and installed. To obtain the proper password please contact CYME International.

1.3.1 Installation steps From a CD

When inserting the CD in the driver the following set of windows open as you click:

CYMCAP for Windows


Enter the password provided by CYME International T&D and CYMCAP will be installed in your computer.

1.3.2 Installation steps From a downloaded file

When requesting the installation of CYMCAP from a file, you will get an email with instructions and the link to the download page together with the installation password. Clicking on the link www.cyme.com/newversion.htm will open the following screen.

Enter the information requested and click on the Download link. The password will be prompted and the installation will proceed.

1.3.3 Setting up the protection key

Once the application is unpacked and installed, the hardware lock, i.e. the protection key, is needed to operate it. The steps to setup the protection key are described in the Appendix titled Protection Key. The information can also be downloaded from: www.cyme.com/newversion.htm, scrolling down to the protection key section.

1.3.4 Windows Settings

For CYMCAP to function properly, you need to insure that you have the following settings on your machine:

Screen resolution: CYMCAP needs that the screen resolution settings to be at least 800 x 600 pixels. The screen should be configured for Small (or Normal) Fonts size with a maximum of 96 dpi. Otherwise, some of the CYMCAP command buttons might not show.

Regional settings: You need to use the Decimal Point. To set this, access your

Windows start menu (Start), select Control Panel, then Regional and Language Options (this can also be named Regional Options on your computer).

CYMCAP for Windows


1. Click the Number tab. In this window insure that: . is used as the Decimal Symbol. Click Apply and then

OK. 2. Click the Currency tab. In this window as well insure that:

. is used as the Decimal Symbol. Click Apply and then OK.

3. When you get back to the main Regional Options window, click OK to close the window.

1.4 The contents of CYMCAP

CYMCAP is equipped with calculating engines to perform Steady State, Cyclic and Transient analyses. These simulation programs produce the results and generate tabular and graphical reports.

Data for the steady state and transient simulators is provided through a Graphical User Interface (GUI) supported by the CYMCAP application libraries. These Libraries are the Study Library, the Cable Library, the Ductbank Library, the Shape Library, the Heat Source Library and the Load Curves Library.

The Study library serves to store and keep organized the different ampacity/temperature scenarios and specific data for the installation. This library has been specially designed to facilitate the study of what if scenarios. The Cable library is needed in all computations since it contains the details of the cable(s) construction. The Load Curves library and the Shape library are essential for transient thermal analysis. Similarly, the Ductbank library is needed for installations featuring duct banks and the Heat source Library is needed when the installation contains an external heat source in a transient thermal analysis.

CYMCAP for Windows


1.4.1 CYMCAP Graphical User Interface

When you open CYMCAP, the programs main working window will be displayed with the CYMCAP Navigator overlaid on it. The description of the commands and use of the main window is described in the next subsections

The CYMCAP GUI Navigator provides access to the various libraries and to the Utilities window. The Navigator closes when you open a Study. You can re-display it by selecting the File > Open Navigator menu item in the main window, by pressing the F3 key or by clicking on the

icon

Each of the library windows is the subject of a separate chapter, starting at Chapter 3.

1.4.2 The CYMCAP libraries and utilities an overview

Access to all CYMCAP libraries is independent, modular and does not rely on any predetermined sequence. The CYMCAP libraries and, therefore, all the application activities ranging from data management to actual simulation runs, are accessed through the CYMCAP Navigator.

Study Library This library contains all the studies performed by the application. CYMCAP relies on the concepts of "studies" and "executions" to organize study cases. A "study" can be viewed as a stand-alone scenario for thermal cable analysis, with several simulation alternatives (what if scenarios), named executions. A study normally pertains to a given installation exhibiting salient characteristics for the cable installation or the ambient conditions. Within a "study" you can define many "executions". An "execution" is used to describe a variant of the base case. See section 5.5 Library of studies and executions.

CYMCAP for Windows


Cable Library The Cable library is a database containing the detailed construction of various types of cables. The contents of the Cable library are used for both steady state and transient analyses. The Cable library, apart from being a database containing the various cable types, is equipped with a module that permits the definition of the cables themselves. Fairly detailed data is required to describe a cable, because the models used for the thermal representation of the cable rely heavily on the exact cable construction. This data is as essential, as the data describing the cable layout and the installation operating conditions.

CYMCAP offers the possibility to provide default cable dimensions based on generic cable construction characteristics, once the materials of the various cable components are defined. This facility is useful for preliminary cable studies but should not be interpreted as addressing all possible manufacturing practices. Chapter 2 is dedicated to describing the Cable library and its various functions, while the used default values for the cable components are given in Chapter 13.

Ductbank Library

The Ductbank library is a database containing the construction details of standard duct banks. A duct bank is a pre-constructed block containing several cable conduits. The purpose of the Duct bank library is to define the geometrical characteristics of these duct banks by specifying the total length, width, conduit number, duct spacing and specific duct diameter so that the information can be used as an integral part of any study for cables installed in duct banks.

The contents of the Ductbank library are used for both steady state and transient analyses. Duct bank geometrical characteristics are crucial in determining external thermal resistances. The Duct bank library, in addition from being a database containing the various duct bank types, is equipped with a module that permits the specification of new duct banks. Chapter 3 is dedicated to describing the Ductbank library and its various functions and facilities.

Heat Source Library

The Heat Source library is a database containing the transient thermal characteristics of external heat sources that may be present within a cable installation layout. External heat sources are deemed third party bodies that either emit or absorb heat depending on their temperature with reference to the ambient environment temperature. The heat source library contains the heat source curves that display the temporal variations of the heat source. Typical examples of heat sources are steam pipes and/or water pipes which temperature can vary as a function of time.

The Heat Source library is supported by another library, the Shape library and is used exclusively for transient thermal analyses. It is often important to include the presence of heat sources in the simulation, since heat sources alter considerably the temperature rise of the cables in an installation. The Heat Source library, apart from being a database, is equipped with a module that permits the definition of new heat source characteristics. In Chapter 4 we describe the Heat Source library and its various functions and facilities.

CYMCAP for Windows


Load Curves library

The Load Curves library is a database containing the description of the various patterns that the cable currents may exhibit as a function of time.

The Load Curves library is used exclusively for transient analysis and is supported by another library, the Shape library. The Load Curves library, apart from being a database, is equipped with a module that permits the construction of the Load Curves themselves. Load curve data is crucial for transient analysis. Load curves are defined in p.u. within the Load Curves library. The Load curve description does not contain actual ampere levels information. The ampere-based Load curves are interpreted during run time as the steady state value of the currents determined for the cables from the steady state thermal analysis. The description of the Load Curves library and its various functions are given in Chapter 4.

Shape Library The Shape library is not a stand-alone library. Instead, it is an auxiliary library dedicated to containing the building blocks for the entries of the Heat Source and the Load Curves libraries. By definition, shapes are defined on a 24-hour basis and represent daily temporal variation patterns. Different shapes can be concatenated to produce weekly temporal profile variations.

Since, however, heat source shapes can only be invoked from the Heat Source library and load curves shapes can only be invoked from the Load Curves Library, there is no risk of confusion. It is essential to enter the required shapes in the Shape library first and then built the Heat Source curves/Load curves to be used for transient analysis. The Shape library, apart from being a database, is equipped with a module that permits the construction of new shapes as well.

Shapes are expressed in p.u. in order to give greater flexibility in describing temperature/heat flux levels for the heat sources and ampere loading levels for the load curves. The same entry format is used to describe both Heat source shapes and load curve shapes. Section 4.2 covers Shape Library management main functions.

It is emphasized again that all p.u. values entered in shapes and Load Curves/Heat Source Curves are expressed in p.u of the values these quantities assumed during steady state thermal analysis.

The CYMCAP Utilities are also accessible from the Navigator. The Utilities are used to manage the data files using powerful functions that help the user to keep projects organized in folders and subfolders or to perform data exchanges between users and computers. The CYMCAP Utilities are fully described in Chapter 9.

1.4.3 Populating the CYMCAP libraries

With the exception of the Study library, the CYMCAP libraries need to be populated before the application models any cable installation. Although typical entries are provided for most input data, it is mandatory; and it is the users responsibility to populate them with figures reflecting actual data. No supplied entry in the application libraries should be interpreted as being typical in any way.

To get accurate cable construction data, the CYMCAP user should contact the cable manufacturer providing the cables for the installation. The more detailed the information, the closer to reality the simulation would be. Dimensions for duct bank, backfills and burial depth should be available from the construction blueprints. Daily and weekly load curves should be available from the electrical system operator.

CYMCAP for Windows


1.5 What you should know about running studies with CYMCAP

The end result of using CYMCAP is to obtain temperatures and currents for the various cables contained in a given cable installation, operating under certain conditions. The following is a typical sequence of steps that are followed when using CYMCAP as an analysis tool.

1. Make sure that ALL the cables of the installation you are about to study are well defined construction-wise and dimension-wise. If this is not the case, try to obtain as much information as possible from the cable manufacturer.

2. Make sure that ALL the cable types that the simulation will use are entered in the CYMCAP Cable Library.

3. Make sure that the duct bank (if any) that the installation employs is entered in the Ductbank library. If the installation does not feature a duct bank, there is no need to populate the Ductbank library.

4. Make sure that the geometrical data of the installation you are about to study as well as the necessary simulation parameters (pipe dimensions, solar radiation intensities, bonding characteristics, ambient temperatures, thermal resistivities, etc.) are available and well defined. Use the graphical User Interface of CYMCAP to define the installation in detail.

5. Make certain that you clearly specify the type of analysis option you wish to perform. The options are:

(a) For steady state analyses: equally loaded, unequally loaded or temperature.

(b) For transient analyses there are three variables in play: temperature, time and current. The user needs to enter two of them and CYMCAP will compute the third one.

Once you have finished entering the installation data for the particular study case, save and submit the study case(s).

6. Make certain that the system frequency is the one desired and that the Unit system you prefer to work have been properly set. Ampacities calculated at 50 Hz are not the same as for 60 Hz. Furthermore, working with the metric or imperial system of units can be convenient depending how the installation and/or cable data were initially provided.

7. Before initiating a transient study, make sure that you have specified loads to all the cables in the installation by assigning to every one of them an appropriate load curve from the library of load curves. You cannot assign a load curve that has not been first defined in the library. It is therefore necessary to first define the load curves you wish to use and include them in the load curve library. You do that by using the Load Curve library manager

8. Examine the simulation results by utilizing the extensive tabular and graphical reports facilities offered by CYMCAP.

CYMCAP for Windows

CHAPTER 2 - THE CABLE LIBRARY 9

Chapter 2 The Cable Library

2.1 Introduction

This chapter describes how to enter new cables in the library and how to manage an existing library of cables. Keeping the cable library up to date with accurate data is extremely important because the results of the ampacity/temperature simulations depend substantially on this data. The cable construction information is one of the major functions of CYMCAP. Access to the Cable library allows you not only to add new cable models, but to modify and delete previously entered cables.

2.1.1 Cable data in studies

The cable library contains the cable data that comprises the detailed construction of the various power cables, material and dimensions. Direct access to the cable library allows the user to utilize one or more cables, within a given execution, for steady state and transient studies.

Note that it is possible to modify the data of a given cable within a particular simulation scenario (execution, or study) without updating the Cable library. This is possible because CYMCAP keeps a copy of the cable from the library within the execution (see also Chapter 5). The information related to cable data within a given execution, is used in the simulations. The program allows the user to transfer cable data from the cable library to the execution in question and vice versa. Unless particular reasons prevail, it is always advisable to harmonize the data in the cable library with the actual data used in the various executions.

Thus, when you have worked on a study and want to save your execution, you will be prompted to specify what you want to do with the modified cable data for that execution, as follows:

Save as is To keep the new information only in the execution without

affecting the data in the cable library.

Save as is (update from cable library)

To restore the cable information in the execution from the information in the cable library, and save the execution with the restored cable information.

Save as is (update to cable library)

To save your execution with the new cable data and update the cable library using the cable information in the execution at the time of saving.

Do note that updating or changing data in the cable library does not update the information in previously saved executions.

CYMCAP for Windows

10 CHAPTER 2- THE CABLE LIBRARY

2.2 Cable library Navigator window

The Cable library is accessed through the CYMCAP Navigator. The Navigator window is shown below. Left click on the Cable tab to display the list of all the cables in the library.

A unique ID and a title identify each cable in the Cable Type Library list. The ID appears in brackets to the left of the cable title. Note that it is highly recommended to enter a unique cable title for each cable. A bitmap is displayed to the left of the list entry to indicate whether the cable is a single-core, a three-core, or a pipe-type cable. See the examples below.

Single-core

Three-core

Pipe-type

When you highlight a cable in the Cable Type Library list, the corresponding cable cross-section is displayed at the bottom of the window. Move the Up and Down arrow keyboard keys to browse through the library list. With this cable library browser capability, CYMCAP allows the user to view the salient aspects of the cable constructions without resorting to detailed editing.

CYMCAP for Windows


2.2.1 Cable library window commands

New To ADD a cable to the Cable Library, position the highlight bar on any cable title and click on the New button. You can either use that cable as a template or create a new one from scratch. If you choose the template option, the highlighted cable will be used as a template.

Edit To MODIFY a cable, position the highlight bar on the cable of interest and click the Edit button. Positioning the highlight bar on the cable, and double-clicking on the left mouse button can accomplish the same task.

Delete To DELETE a cable, position the highlight bar on the entry and click the Delete button.

Delete Tagged

This is used to delete more than one cable at a time. The Tag mode needs to be turn on first. This is done though the CYMCAP Utilities, which are described in section 10.6 Tag specific items from the Libraries.

Filter Editor

The Filter Editor command helps the user to build filters to quickly locate a cable using particular characteristics. This feature is most useful when the cable library contains a large number of cables. The Filter Editor use is covered in section 2.8.

Apply Filter

This button gives direct access to the application of filters previously built in the Filter Editor. When you click on the Apply Filter button, a combo box will appear at the bottom of the CYMCAP window to let you select your pre-defined filter.

CYMCAP for Windows


2.2.2 Cable library pop-up menu

When you right-click on the Cable library window, the following pop-up menu will appear.

Search Utility Primary filter that permits the selective display of the major cable types. With this utility, the search can be narrowed down to single-core, three-core or pipe-type cables.

View All Selecting this option will list all cables in the Cable Type Library list.

View Pipe-Type To show only the pipe-type cables in the Cable Type Library list.

View Single-Core To show only the single-core cables in the Cable Type Library list.

View Three-Core To show only the three-core cables in the Cable Type Library list.

View Tagged Only This is used to view only the cables that are Tagged. The Tag mode needs to be enabled first; this is done though the CYMCAP Utilities, which are described in section 10.6 Tag specific items from the Libraries.

Tag mode check box in the Utilities window.

CYMCAP for Windows


View through a Filter

This is an information field that indicates whether or not the cable type list is currently being viewed through a filter.

Sort by Cable Id Sorts the displayed cable entries in the list by cable ID.

Sort by Cable Title Sorts the displayed cables by cable title.

Resynchronize This function operates only in multi-user network licenses. It serves to refresh the list of cables.

Tag/UnTag To select (tag) or unselect (remove tag) a cable. Active when the Tag mode has been enabled (in the Utilities window).

Tag All To selects all cables in the view. Active when the Tag mode has been enabled.

Untag All To unselects all cables. Active when the Tag mode has been enabled.

2.3 Cable design data window elements

The Cable design data window is composed of two basic parts.

The top part provides a summary of the library item you are looking at, and the bottom part of the cable screen shows the cross-section of the cable selected identifying the layers with the data associated.

The top part summary includes:

List of Cables Drop-down list of the available cables. The one shown in the field is the one for which the data is currently displayed.

Number of Conductors One for single core cables ,

and three for three core cables

No other options are supported.

Cable Type CYMCAP supports six cable types. Five of these types are conceptual and are only used by the application to assign default dimensions to the cable components. The sixth one, European Construction, is used to model cables with sheaths external to concentric neutrals (which is commonly used in Europe). The cable type is defined in the first stages of cable definition (see example below) and they are as follows: PIPE TYPE cables LPOF cables CONCENTRIC NEUTRAL cables EXTRUDED cables OTHER (reserved for cables that cannot be directly classified to

any of the above categories). EUROPEAN CONSTRUCTION

CYMCAP for Windows


Speed Bar A speed bar appears below the summary of the cable displayed. It lists the components available for the type of cable selected; and

indicates which component are currently used with a . When you click on the speed bar buttons, you toggle between Yes and No to display and hide the layer in question. When you enable a component for which the database does not contain associated data, the list of layers in the bottom part of the window will show you where data needs to be entered with red ellipses, or with the word unknown. When a component is not available for the type of cable selected, the

speed button for that layer will show a lock .

Notes: There is no provision for default dimension assignment to the cable type OTHER or EUROPEAN CONSTRUCTION.

There are no components availability restrictions for the cable type OTHER. Note that such restrictions do apply to the remaining types.

No pipe type cable can be modeled under the OTHER construction.

The component availability restrictions are seen in the data entry dialog boxes as locks not allowing the user to select a particular component construction depending on the remaining data entered so far. These restrictions are not meant to be rigid and they simply reflect one philosophy of manufacturing practice from the very many available.

In the EUROPEAN CONSTRUCTION type the Sheath/Sheath Reinforcement layers appear outside the Concentric Neutral layer on the layers speed bar.

This button gives access to the Short Circuit Ratings (/SCR) add-on module of CYMCAP.

CYMCAP for Windows


The bottom part of the cable screen shows the cross-section of the cable selected identifying the layers with the data associated to each one. The name of each layer appears as a hyperlink with the basic cable data listed besides the layers name. If you do not see it, select the View > Details menu item. Also, when a layer in the cable cross-section is not colored (i.e. only outlined in black), it means that extra data needs to be entered.

To access the detailed data dialog box for a layer, you simply click on its name on the list next to the cable cross-section.

Two more pieces of information appear in the bottom part of the window:

Voltage CABLE RATED VOLTAGE: This is the voltage used to calculate the dielectric losses in the cable. This voltage should be the rated Line-to-Line voltage of the installation. Even if the cable is used in a single-phase circuit arrangement the hypothetical Line-to-Line Voltage needs to be entered.

Cond. Area CONDUCTOR CROSS SECTIONAL AREA: This is the nominal conductor area and should be entered as such. This area is interpreted by the application to be the "effective" conductor area and is this value that will be used by the program for resistance calculations. The user has access to standard conductor sizes ordered in increasing sizes of wire. Conductor sizes can either be selected from the list or typed explicitly.

CYMCAP for Windows


2.4 Steps to create a new cable

The necessary steps to create a new cable and add it to the cable library are summarized below. An example applying those steps is the subject of section 2.6 Creating a new cable - Example

Step 1: Identify the layers and cable components and decide how they are to be modeled, according to the component availability CYMCAP offers. The component availability is listed starting at section 2.5 Cable components, materials and construction.

Step 2: Identify the cable components and define the materials they are made of. In case the program does not support a material for a given component, make certain that the necessary constants are available so that you can enter it as custom.

Step 3: Identify the cable components dimensions and make certain that every layer thickness is well identified. CYMCAP relies on layer thickness to conjecture equivalent layer diameters for both single core and three-core cables of all constructions. Furthermore, make certain that accurate data concerning length of lay for concentric wires armour and tapes are also available. These data are important to correctly estimate loss factors in 2-point bonded systems. It is always useful to ascertain that the cable construction dimensions are available from the manufacturer. The more the cable construction details are known, the less one has to rely on the default dimensions provided by the program.

Step 4: Select the system of Units for the session. Both Imperial and Metric systems are supported by CYMCAP. The cable dimensions can be entered in either inches (Imperial system) or mm (Metric). Once the cable dimensions are entered in any system they can be visualized in the other system by simply switching the Unit

system by clicking on the or icon.

Step 5: Enter the cable components and dimensions for the cable (see 2.5 Cable components, materials and construction).

Step 6: SAVE the newly entered cable data. Menu command File > Save or File > Save

As. You can also save by clicking on .

Step 7: Display a new listing of the library of cables in the Navigator (F3) and make sure that the newly entered cable appears on the list.

CYMCAP for Windows


2.5 Cable components, materials and construction When a cable is entered in the library, the user has considerable flexibility in specifying

both the available cable components as well as the materials these components are made of. In the paragraphs that follow, the cable components supported are outlined along with the parameters the program will use internally as a function of the component construction. Parameters and/or constants used by the application follow the ones in IEC-287-1-1/1994.

To have access to a layer dialog box to enter/edit the related data, you simply click on its name in the Cable Design Data window. The related dialog box will be displayed to the left of the screen. The top part of each specific Data dialog boxes feature a Layers navigator that you use to display the data dialog box associated with another layer. Below is an illustration of how the layers names are displayed in the Layers drop down list.

Means that this layer is part of the cable selected.

This layer is available for the cable selected with the configuration defined in the database, but is not part of the current cable.

Sample: more or fewer layers in different positions might appear depending on type of cable selected.

This layer is not available for the cable selected with configuration defined.

Data dialog boxes are available for the following types of layers. Each are discussed in

separate subsection in this chapter. Conductor, see page 18 below, Conductor shield, page 21 Insulation, page 22 Insulation screen, page 23 Sheath, page 24 Sheath Reinforcing, page 24 Skid wires (for pipe type cables only), page 25 Concentric neutral wires, page 25 Armour/Reinforcing tape, page 26 Armour Bedding/Armour Serving, page 27 Jacket, oversheath and pipe coating material, page 28

CYMCAP for Windows


A number of commands are common to all Data dialog boxes. You will find them at the bottom of the windows:

Previous Displays the previous layer on the list. Next Displays the next layer on the list. Reset Erases all changes made during the current editing session. Ok Retains the information entered in the window, displays the data on the

cross-sectional display and closes the window. Cancel Closes the data window without retaining the information entered in that

window from the moment it was last displayed. Clicking the X at the right hand top corner has the same effect.

2.5.1 Conductor data

CYMCAP for Windows


2.5.1.1 Conductor material

The conductor material can be copper, aluminum or any other custom material. Independently of the choice, the program needs the DC conductor material resistivity at 20 C (in -m) and the temperature coefficient for the resistance (/K at 20C). When aluminum or copper is selected the program assumes the following values:

Copper =1.7241e-08, =3.93e-03 Aluminum =2.8264e-08, =4.03e-03 When the user selects the conductor material, these values must be provided.

Resistance values per IEC 228 The resistance of the conductors can be calculated or taken from the tabulated values in the Standard IEC 228. The conductor material, type and construction are all taken into account during the course of the calculations. The user may choose the option to obtain the resistance of the conductor from the resistance tables of the Standard IEC 228. Depending on conductor cross-sectional area, construction type and material, a different resistance value will be considered. The following restrictions and/or assumptions apply:

IEC-228 resistance values apply ONLY to copper and aluminum conductors. IEC-228 resistance values pertaining to PLAIN conductors are considered. In other

words, the current version of the program does not support METAL-COATED conductors.

For conductor sizes in-between standard tabulated values, linear Interpolation is used to arrive at the estimated resistance value.

If the user wishes to consider resistances applicable to class 1-conductors (table I of IEC 228), the choice "solid" must be used for the Conductor construction option.

If the user wishes to consider resistances applicable to class 2 conductors (table II of IEC 228), the choices "stranded", "compact/compressed", "sector-shaped" and "oval" are pertinent. No other conductor construction option is supported for IEC-228 compatible calculations.

If a conductor cross-section is entered for the cable and not supported by IEC 228, the program will revert to the alternate mode, i.e. the resistance will be calculated.

For conductor cross-sections, corresponding to blank entries in the tables 1 and 2 of IEC 228, the program will revert to the alternate mode, i.e. the resistance will be calculated.

2.5.1.2 Conductor construction

The following choices for conductor construction are supported:

Stranded (round) Compact or compressed (round) 4 segments Hollow core 6 segments Sector shaped Oval

CYMCAP for Windows


Solid Segmental Segmental peripheral-strands The selections available are contingent upon the cable type selected as well as the

conductor dimensions. The program will indicate which options are valid by highlighting them in the Construction selection menu of the Conductor data dialog box.

Means the option selected.

Means that the option is available for selection.

Means that the option is not available for the cable selected .

2.5.1.3 Drying and Impregnation

This information is used to properly correct for skin and proximity effects when calculating the conductor resistance.

Skin and proximity effect loss factors Skin and proximity effects are used to calculate the ac resistance of the conductor by adjusting the dc conductor resistance by the factors Ys (skin effect) and Yp (proximity effect) as follows:

Rac = Rdc (1 + Ys +Yp): Rac, Rdc are AC and DC resistances, respectively. In calculating Ys and Yp the constants Ks and Kp are used. The program assumes the following values based on conductor construction. Note that these values have been compiled for copper conductors. Nevertheless, the same values will be assumed for aluminum except for segmented conductors which value is shown in the table. The approximation is considered to be on the safe side.

Conductor Construction Ks Kp Round stranded dried and impregnated 1.00 0.80 Round stranded not dried and impregnated 1.00 1.00 Round compact dried and impregnated 1.00 0.80 Round compact not dried and impregnated 1.00 1.00 Round segmental (Copper 4 segments) 0.435 0.37 Round segmental (Copper 6 segments) 0.39 0.37 Hollow, helical stranded, dried, impregnated * 0.80 Sector shaped dried and impregnated 1.00 0.80 Sector shaped not dried and impregnated 1.00 1.00 Round segmental (Aluminum 4 segments) 0.28 0.37 Round segmental (Aluminum 5 segments) 0.19 0.37 Round segmental (Aluminum 6 segments) 0.12 0.37

* See calculation method in table 2 of the IEC Standard 287-1-1 The user can also enter different values using the CYMCAP GUI as shown in the following figure.

CYMCAP for Windows


2.5.2 Conductor shield data

The program supports "conductor screens", as a cable component The term "shield" is often used as equivalent to the term "screen".

Notes:

Non-metallic screens are modeled as part of the insulation.

If a conductor shield is modeled, the program will assume its material to be the same as the insulation material.

The conductor shield is taken into account as part of the insulation when the thermal resistance is computed, but it will not be considered as part of the insulation for the calculation of the dielectric losses.

CYMCAP for Windows


2.5.3 Insulation data

The insulation materials supported are listed below along with their assumed thermal resistivities.

The user can also enter a custom material. In this case the thermal resistivity has to be provided along with the appropriate coefficients for dielectric loss calculations (tan() and ). Thermal resistivity values are shown in C-m/W.

Material i Solid type/mass impregnated non draining cable

6.0

LPOF self contained cable 5.0 HPOF self contained cable 5.0 HPOF pipe type cable 5.0 External gas pressure cable 5.5 Internal gas pressure preimpregnated cable

6.5

Internal gas pressure mass impregnated cable

6.0

Butyl rubber 5.0 EPR 5.0 PVC 6.0 Polyethylene 3.5 Cross linked polyethylene (XLPE) (unfilled) 3.5 Cross linked polyethylene (XLPE) (filled) 3.5 Paper-polypropylene-paper-laminate 6.5

2.5.3.1 Dielectric loss factors for insulating materials

The program assumes the following values for loss-related factors in the dielectric (values taken from IEC 287, 1988 revision).

Dielectric Loss Factors Paper Impregnated Cables

tan() Impregnated, pre-impregnated or mass-impregnated non-draining 4.0 0.01

Self-contained, oil filled, up to 36kV 3.6 0.0035 Self-contained, oil filled, up to 87kV 3.6 0.0033 Self-contained, oil filled, up to 160 kV 3.6 0.0030 Self-contained, oil filled, up to 220 kV 3.6 0.0028 Oil-pressure pipe-type 3.7 0.0045 External gas-pressure 3.6 0.004 Internal gas-pressure 3.4 0.0045 Butyl rubber 4.0 0.05 EPR up to and including 18/30 (36) kV 3.0 0.020 EPR above 18/30 (36) kV 3.0 0.005 PVC 8.0 0.1 PE (HD and LD) 2.3 0.001 XLPE up to and including 18/30 (36) kV (unfilled) 2.5 0.004 XLPE above 18/30(36) kV (unfilled) 2.5 0.001 XLPE above 18/30(36) kV (filled) 3.0 0.005 Paper-polypropylene-paper-laminate (PPP or PPL)

3.5 0.00095

CYMCAP for Windows


The dielectric loss factors are only taken into account when cables operate at equal or greater phase to ground voltage than the following (IEC 287):

Cable Type Voltage Level (kV) Insulated with impregnated paper Solid type 38.0 Oil-filled and gas pressure 63.5 Butyl rubber 18.0 EPR 63.5 PE (Hd and LD) 127.0 XLPE unfilled 127.0 XLPE filled 63.5 PPP or PPL 38.0

Note:

Dielectric losses for voltages lower than indicated are always taken into account for user-defined insulation.

2.5.4 Insulation screen

When copper or aluminum insulation screens are specified, the program performs calculations according to IEC-287/1994 in order to calculate the thermal resistance of the screened insulation. These calculations apply to three core cables only.

For single core cables the insulation screen is treated as a separate layer.

When the semiconducting insulation screen option is selected, the insulation screen will be considered as part of the insulation for both single core and 3-core cables. The term "shield" is commonly used for "screen".

For 3-phase cables, the program assumes that the insulation screening applies to the insulation of the individual conductor cores. The same is true for sector-shaped cables.

The term "belted" is utilized by the program to identify 3-phase cables with no screens featuring an additional layer of insulation encompassing all 3 conductors.

CYMCAP for Windows


2.5.5 Sheath

Sheath material and resistivity

The sheath electrical resistivity (-m at 20C) and the thermal coefficient (1/C) are required for the calculations. Supported materials read as follows:

Material

Lead 21.4e-08 4.0e-03 Aluminum 2.84e-08 4.03e-03 Copper 1.72e-08 3.93e-03

The user can enter any other material by selecting Custom in the Material list, but in this case the values of and must be entered; the program will display a dialog box to allow the user to do so.

Sheath construction

The program supports both radial and longitudinal construction for sheath corrugation for the case of aluminum, copper and custom only. When default dimensions are set by the program, the calculation for the sheath thickness followed for the case of aluminum, is applied to copper and custom; see section 11.6 Sheath related defaults.

2.5.6 Sheath Reinforcing Material

CYMCAP allows the user to enter a sheath reinforcement tape for sheathed cables or tape over insulation screen for pipe type cables. The thickness refers to the radial dimension and it is used to compute the diameter and vice versa. Width is the axial dimension of the tapes as shown in the illustration below.

The length of lay is the longitudinal distance required for a particular tape to give one revolution around the previous layer (see the figure below). When the length of lay is not available, a value of 10 times the previous layer diameter can be used.

CYMCAP for Windows


2.5.7 Skid wires (for pipe type cables only)

Skid wires are applicable to pipe type cables only. Despite the fact that skid and concentric wires share similar information, skid wires data entry dialog boxes are dedicated to pipe type cables. No cable can have both skid and concentric neutral wires. The program assumes that the skid wires are semicircles. Two skid wires will be assumed present, by default, by the program but the number can be changed; see section 11.5 item 5. Skid Wires. Length of lay considerations applicable to skid wires, are identical to the ones for concentric neutral wires.

2.5.8 Concentric neutral wires

Concentric neutral wires are, usually, return wires in distribution cables. The program assumes that these wires are bare (no insulating or plastic wrap that they may be equipped with, is supported). Data for the concentric neutral comprise the wire size, the number of wires as well as the length of lay; see section 11.2 Concentric neutral cables for defaults. The concentric wires may be made of copper, brass, zinc, or stainless steel. CYMCAP supports flat-straps concentric neutrals.

Material Copper 1.7241e-08 3.93e-03 Aluminum 2.8264e-08 4.03e-03 Stainless steel 70.000e-08 0.000000 Zinc 6.1100e-08 0.004 Brass/Bronze 3.5000e-08 0.003

If other than the above materials are to be used (select Custom to do so), the user has to provide resistivity and temperature coefficient. is expressed in -m at 20 C and in 1/C.

CYMCAP for Windows


2.5.9 Armour/Reinforcing tape

CYMCAP supports cable armour assemblies in the form of either wires or tapes.

For the case of armour wires, the program requests as data the number of wires (if not touching), the wire size and the length of lay. For the case of armour tapes, besides the number of tapes and the length of lay, the tape width must also be provided.

For thermal calculations the armour resistivity as well as the thermal coefficients are also needed

The following materials are internally supported: (A is expressed in -m at 20C and in 1/C).

Material A Custom non magnetic tape User-defined User-defined Custom, magnetic armour wires User-defined User-defined Custom magnetic tape User-defined User-defined Custom, non magnetic wires User-defined User-defined Steel wires touching 13.8 E-08 0.0045 Steel wires not touching 13.8 E-08 0.0045 Steel tape reinforcement 13.8 E-08 0.00393 Copper armour wires 1.721 E-08 0.00393 Stainless steel armour 70.0 E-08 0.0 IEC TECK armour 2.84 E-08 0.0043

If any other material is to be used (select Custom to do so), the user has to supply the above parameters.

When magnetic losses are of importance, additional data needs to be entered to model the eddy currents and hysterysis losses of the armour. The parameters needed are the longitudinal and transverse permeability (AME and AMT respectively) as well as the angular time delay . The user can enter these parameters or have the program select them. When the program selects, it will assume:

AME=400, AMT=10 for steel wires touching or AMT=1 for steel wires not touching and GAMMA=45 degrees. The same values will be assumed for steel tapes. Magnetic properties modelling for the

armour is supported only for steel armour assemblies.

CYMCAP for Windows


2.5.10 Armour Bedding/Armour Serving

CYMCAP defines as armour bedding the layer that is normally encountered below the armour assembly. Armour serving is defined as the layer of protective coverings sometimes found above the armour assembly. The following materials are supported for armour bedding.

Material Thermal resistivity (C-m/W)

Compounded jute and fibrous materials

=6.00

Rubber sandwich =6.00 If any other material is to be used, the user must provide the thermal resistivity. Values

for many insulating materials are given in section 2.5.3 Insulation data.

CYMCAP for Windows


2.5.11 Jacket, oversheath and pipe coating material

The following materials are supported for cable jacket oversheath and pipe coating (for pipe type cables only).

Material Thermal resistivity () Compounded jute and fibrous materials

6.0

Rubber sandwich 6.0 Polychropropene 5.5 P.V.C up to and 35 kV 5.0 P.V.C. above 35 kV 6.0 Butyl rubber 5.0 Coal tar wrapping 5.5

Note:

Pipe and pipe coating material is entered in the specific installation data and not in cable data. See Section 5.8.3 Specific cable installation data for all the details.

CYMCAP for Windows


2.6 Creating a new cable - Example

In this section, we will go through the stages of creating a new cable for illustration purposes. The cable will be a typical 250KCMIL distribution cable, rated 35 kV. The cable features Aluminum stranded conductor, XLPE insulation and copper concentric neutral wires. In what follows a typical sequence of the steps/screens/dialog boxes required to enter a cable is outlined.

To create a new cable in the library, position the highlight bar on any cable and click on the New button. If the existing cable is to be used as a template for your new one, answer Yes to the ensuing prompt. In our current example, No existing cable is used as a template. Then, the following screen indicates that it is required to enter a cable ID and a cable Title.

The cable ID should be unique because it is used internally as a database index. It is the cable ID and the cable title that appear in the cable type library browser. Comments are optional, but frequently important.

Click OK to accept the data entered and the screen that follows allows the user to begin defining in details the cable construction, from the point of view of component availability.

First specify whether the new cable will be a single-core or a three-core, by clicking on one of the buttons next to the Cable Type combo box:

To specify a single-conductor cable.

To specify a three-conductor cable

Then specify the cable type as EXTRUDED in the Cable type combo box.

CYMCAP for Windows


The program then prompts for the nominal cable voltage (kV); indicate 35 kV, then the click OK button.

The next piece of data required is the conductor size. Open the standard conductor sizes scroll list and select 250 KCMIL. A default Conductor Area will then be displayed, you may change this.

Once the conductor size and the voltage are entered, the program is ready to accept more instructions by displaying the following screen. You will notice that the Speed Bar now displays the layers that are possible to be added based on the information entered up to this point.

CYMCAP for Windows


It is seen that no dimensions are entered at all, as the encircled quantities show. The program also indicates that no materials were defined at all. Before proceeding to materials and dimensions, we must first specify the generic cable components. Among the generic components only the cable insulation has been enabled so far (see the Speed Bar). Let us enable the insulation screen, the concentric neutral and the jacket.

Note that the concentric wires were not drawn yet. They will be displayed on the cross-section when specific data is entered later.

CYMCAP for Windows


Once all the generic components for the cables are entered, we tell the program that their definition has ended by clicking on the Complete Cable button appearing on the top part of the window. The program then displays the Data dialog box for the first generic component, the conductor, in order to accept further instructions about materials, construction type and dimensions. Clicking on the Reset button will display the last saved data. Note that the program will allow saving only once all the data required defining all the layers of your cable will be entered.

Several alternatives for the conductor material and construction are available. Choices that are either not permitted or irrelevant, based on the data entered so far, are locked, as the appropriate locker symbol next to them indicates, and are not available for selection.

Define the material, construction and dimensions on the same screen and to proceed to the following generic component, click the Next button at the bottom of the Conductor Data dialog box. You will notice that when you click Next, the layers list in the cross-section window will now display the information you have just entered. Clicking OK has the same effect on the cross-section, but it will close the Data dialog box.

CYMCAP for Windows


The next layer of our example is the insulation. The dialog box for the insulation is as follows:

The information that needs to be entered here includes the maximum design (steady

state) and emergency (transient) operating temperatures the particular cable can withstand. Default values are assigned automatically depending on the insulation type material selected by the user. The program will use these values for the corresponding analysis options unless changed by the user.

You proceed in this fashion for the remaining layers. Missing data is indicated with a red circle or with the word unknown on the cross-section display. Once all the necessary data is

entered, the Save button will be enabled, as well as the corresponding File > Save and the File > Save as menu items.

Note that when you open a cable that is contained in the library, the Save button and the Save menu option are disabled until you make a change. When they are enabled and you use them, the program saves the data under the Cable ID and the Cable Title that are displayed.

The Save As menu option remains available even if you do not make a change to the cable displayed. If you use that last option, the program will prompt you to enter new Cable ID and Cable Title.

CYMCAP for Windows


The completed cable looks as follows:

Additional input data like length of lay, internal and external radius of corrugated sheath, dimensions of flat-strapped concentric neutrals, etc, can be displayed in lieu of the list as shown above by pressing on the space bar.

Clicking on the hyperlinks will open the corresponding data dialog box, with the corresponding field highlighted in it.

CYMCAP for Windows


2.7 Useful considerations

2.7.1 Cable layers

a. The sequence of cable components in CYMCAP assumes a start from the conductor and expands outwards with the insulation, insulation shield, sheath, sheath reinforcement, concentric neutral wires, armour bedding, armour, armour serving, and finally the jacket. It is in this spirit that the terms are used in the program and their definition should be respected.

b. When creating a cable, it is possible that layers not directly identifiable with any of the available components are encountered. Closer inspection, often, reveals that one of the available layers by the program can be directly used because different names are often interchangeably used for the same layer. For example, CYMCAP will not accept a cable jacket once armour is defined for a given cable. The cable jacket then can alternatively be modeled as armour serving.

c. If the need for a layer not supported by CYMCAP arises, you can combine two layers in one by calculating an equivalent thermal resistivity for two layers in series. This can be particularly useful for the cases where materials of different thermal resistivity are used for either armour serving or bedding. A conservative approach from a thermal resistance point of view would be to model the two layers as one having as thermal resistivity the one with the higher value.

d. When a layer is deleted, the user does not have to reflect the change in the dimensions imposed beyond that layer towards the cable surface. The program will automatically adjust the dimensions accordingly. The same holds true if a layer is inserted. If a layer is deleted and then reinserted, the layer dimensions are automatically restored as long as the cable was not saved or that the program session has not been terminated.

2.7.2 Particular modeling

a. When cables with oval conductors are to be modeled, the user should enter the

equivalent round conductor diameterD D Dmajor or= min , where Dmajor and

D ormin are the corresponding lengths of the major and minor elliptical axis of the oval conductor.

e. Model metallic conductor screens as part of the conductor. Similarly, model semiconducting conductor screens as part of the insulation, include semiconductive swellings in the semiconductive screen over the insulation, etc.

f. To model armour wires imbedded in the jacket, you can represent the portion of the layer below the wires as armour bedding, the wires as armour, and the portion of the layer above the wires as armour serving.

g. Interjackets and jackets around armour assemblies, should be modeled as armour bedding and serving, because the program does not allow for jacket when armour is present.

h. Metallic parts that are associated with circulating currents should be modeled as sheaths, even if they are termed screens. This assures that the program calculates properly the loss factors.

CYMCAP for Windows


2.7.3 SL-type cables

SL-type cables are 3-conductor cables characterized by the fact that every core has its own sheath or armour wires. The program supports either options but not both simultaneously.

The SL-type construction is identified during the cable data entry by specifying either individual sheath or individual armour construction. Note that the following restrictions apply to the construction of SL-type cables:

SL-type cables are not permitted to have metallic insulation screens. No sheath reinforcement is supported for SL-type cables. Corrugated sheaths are not supported for SL-type cables. SL-type cables will either have individual sheaths or individual concentric neutral

wires but not both.

When SL-type cables are modeled, the bonding arrangement selections available are either single point bonded or two point bonded.

Default dimensions for SL-type cables sheaths and armour wires follow the same defaults as for single-core cables.

2.7.4 Custom materials and thermal capacitances

CYMCAP gives the user the possibility to enter custom materials for many of the cable components metallic or not. For many non-metallic parts as: insulation, armour bedding, serving etc. the thermal capacitance of the particular component is needed for transient ampacity calculations. Although the program will consider specific thermal capacitance values for known and tabulated selected material types, when custom materials are specified typical values are assumed for the thermal capacitances. The application supports ASCII fields for any type of user-defined components so that their name, as well as their parameters can be clearly identified. The following screen illustrates the concept.

CYMCAP for Windows


2.8 Filter Editor

It is not uncommon to desire to locate cables with particular construction characteristics, in addition to the major generic classification provided by the primary filter that is the Search Utility of the Navigator pop-up menu (see section 2.2.2 Cable library pop-up menu). In this case, invoking the more advanced search/filtering facilities of CYMCAP is needed. From the cable library navigator screen, invoke the Filter Editor as shown below:

Once the filter is invoked, the user is presented with the option to specify any particular cable characteristics for the search, as shown below.

In this particular example illustrated, single core, medium voltage cables (rated higher than 6.00 kV) featuring a conductor cross-section larger than 1250 mm2, copper conductor of stranded construction, with concentric neutral and XLPE insulation are specified for the search.

CYMCAP for Windows


Notes:

More detailed searches comprising non-metallic components can also be included. To bring any cable component attribute in the Filter elements selected list and

collect all the desired cable characteristics as search attributes, highlight the desired feature and bring it over by clicking on the right arrow.

To remove a selection, highlight the selected attribute to the right and use the left arrow to remove it from the selection list.

The specified search characteristics are summarized at the bottom of the screen in the Filter to apply on Cable Library field.

A name can be given to the particular filter search characteristics set and saved for future reference.

CYMCAP for Windows

CHAPTER 3 - THE DUCTBANK LIBRARY 39

Chapter 3 The Ductbank Library

3.1 Introduction

Duct banks are pre-arranged assemblies of conduits where cables are placed for underground installations. This chapter describes how to enter new duct banks in the library and how to manage an existing library of duct banks. The geometrical disposition of these pre-constructed assemblies is needed to perform the simulations for cables placed in the conduits of the duct bank. Access to the Ductbank Library allows you not only to add a new duct bank, but to modify and delete previously entered duct banks.

The Ductbank Library contains, and permits building, standard duct banks only. These are duct banks with all the ducts being of the same size and aligned horizontally and vertically. The number of rows and columns do not have to be the same, but all ducts in a given row or column must be aligned. Non-standard duct banks, ducts of different size, and unaligned ducts can be entered in a CYMCAP simulation when the installation is being set up. An example on how to build non-standard duct banks can be found in section 5.10.4 Defining standard and/or non-standard duct banks.

3.2 Ductbank library management

In the CYMCAP Navigator, click on the Ductbank tab in the CYMCAP to access the Ductbank library. The list of the duct banks in the library is shown as follows:

Each duct bank available in the Library is identified with its unique ID and NAME.

CYMCAP for Windows

40 CHAPTER 3- THE DUCTBANK LIBRARY

A picture showing the duct bank cross section is displayed in the viewer pane to the right of the window for the corresponding duct bank in the list when the highlight bar is positioned on the name. Press the Up and Down arrow keyboard keys to browse through the library. CYMCAP allows the user to view the salient aspects of the various duct banks without resorting to detailed editing.

To ADD a duct bank to the library, highlight any library entry and click the New button located to the right of the Navigator list. You will be prompted with the option to either use a duct bank as a template or create a completely new one. If you choose the template option, the entry the highlight bar is on will be used as the template.

To MODIFY a duct bank highlight the duct bank of interest and left-click with the mouse on the Edit button located to the right of the Navigator list. The same task can be accomplished by positioning the highlight bar on the entry of interest and double-clicking on the left mouse button.

To DELETE a duct bank you position the highlight bar on it and left-click with the mouse on the Delete button located to the right of the navigator list. You can also click and drag any entry from the library to the disposal bin shown in the upper right corner of the navigator window.

3.2.1 Creating a new duct bank. An illustrative example.

A new duct bank will be created for illustration purposes. The duct bank will be a sample 3x3 duct bank, i.e. consisting of 3 series of conduits and 3 columns of conduits. In what follows, a typical sequence of the steps/screens/dialog boxes required to enter a new duct bank is outlined for illustration purposes.

To create a new duct bank in the library, position the highlight bar on any entry and click on the New button. If the existing duct bank is to be used as a template for the new one, answer Yes to the ensuing prompt.

For this example, we will not use an existing duct bank as a template.

The program then prompts for the entry of a Duckbank name.

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CHAPTER 3 - THE DUCTBANK LIBRARY 41

Once the duct bank name is entered, two windows are displayed side by side: the Ductbank Library designer dialog box and the Ductbank design data window. The geometrical details outlining the duct bank construction are entered in the Ductbank Library designer dialog box. The cross-section of the duct bank is shown in the Ductbank design data window is updated as the data characteristics are entered in the Ductbank Library designer dialog box.

When the cursor is positioned into any data entry field, the dimension in question is outlined on the small auxiliary help screen appearing in the Ductbank Library designer dialog box.

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42 CHAPTER 3- THE DUCTBANK LIBRARY

The following illustrates the new duct bank with its complete characteristics.

Click OK to accept the data entered and save the new duct bank in the library. The newly entered duct bank now appears as a new entry in the Ductbank Library.

CYMCAP for Windows

CHAPTER 4 - LOAD CURVES/HEAT SOURCE CURVES AND SHAPE LIBRARY 43

Chapter 4 Load-Curves/Heat Source Curves and Shape Libraries

4.1 Introduction

This chapter describes how to manage the last three libraries of CYMCAP. In what follows, the terms Load curve and Heat source curve are treated as conceptually identical, as far as library management is concerned, despite their physical difference. The term Curve, wherever used, means both. Whatever statements are made, however, for Load curves, apply equally well to Heat Source curves. These curves are used by CYMCAP only for TRANSIENT ANALYSIS.

Load Library This library includes the available load curves, which are the patterns of current versus time, and that are used to indicate how the current in a given cable varies as a function of time over a specific time period. Access to a wide variety of loading patterns is thus assured for various transient studies. Much like the various types of cables, the different load curves are kept in a separate library. You can think of a Load Curve as being the weekly load profile of a particular feeder section.

Heat Source Library This library contains the Heat Source curves, which are the patterns of heat source intensity versus time, and that are used to indicate how the heat source intensity varies as a function of time over a specific time period.

The Shape Library contains the shapes that are the building blocks used to construct both the Load curves and the Heat Source curves. The Shape library is common to both the Load Library and the Heat Source Library. A shape can be related to the daily load profile of a particular feeder section.

4.1.1 Curves and Shapes

CYMCAP uses the notion of Shapes to assure through modularity flexibility and efficiency in describing the various curve variations versus time.

A Shape is essentially a curve that spans at most 24 hours. Shapes are used to represent daily variations and feature, typically, hourly resolution. They need, however, to last at least 10 minutes since the numerical techniques of the CYMCAP engine do not have the resolution to properly compute shorter variations. The various shapes can be stored separately in the Shape Library. This shape library can be accessed when constructing a curve that spans one or more days. It is useful therefore to conceptualize the shapes not as stand-alone short-term Load variations but as the building blocks for the Load curves.

A load curve describes the variation of the Loading of Cable/Heat Source intensity with time. It may be composed of one or more shapes, depending on the duration of the transient to be simulated. Curves can span time intervals ranging from a fraction of a day to one week.

It is important to realize that CYMCAP forms an association between shapes and curves. No curve can be defined without a shape, and at least one shape is necessary to construct a curve. When shapes are modified within the shape library, these actions directly affect the curves associated with these shapes. No shape that belongs to an existing curve can be deleted.

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44 CHAPTER 4 - LOAD CURVES/HEAT SOURCE CURVES AND SHAPE LIBRARY

N.B.: All variations, within the context of the curve definition, are expressed in p.u. The base quantity is the current/heat source intensity the cable/heat source carries at steady state as resulted/defined from the steady state ampacity or temperature simulations.

CYMCAP is also capable of interpreting recorded field measurements and construct Load Cur

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