Abstract Development of nation depends upon electricity energy and at present scenario there is large gap between electric generation and load. This gap can be filled with proper control, monitoring and coordinating the distribution components at power sector. In this view, Automation of power distribution system has increasingly been adopted by power utilities worldwide in recent years. As part of its efforts to provide a more reliable supply to the customer and to enhance operational efficiency. The automation of the power system can be achieved by SCADA. It is a boon to the automation concept of dynamic technology. SCADA refers to “SUPERVISORY CONTROL & DATA ACQUISITION”. Karnataka Power Transmission Corporation Limited (KPTCL) has undertaken steps to automate existing substation and new substation by use of most advanced controlling and monitoring technology ABB SCADA. Project was conceived in the year 2002, tenders floated in the year 2006 and project awarded to M/S ABB in December 2006. 220/110/11kV Receiving Station Bijapur near Shivgiri Ukkali road and 110/11kV Receiving Station Bijapur at City were some of the substations automated in this project. Monitoring, controlling and coordinating the distribution equipments and trouble shooting at fault are challenging task for engineers. These aspects make the power and energy system engineers to know more about controlling of power system. In this
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Transcript
Abstract
Development of nation depends upon electricity energy and at present scenario there is large gap
between electric generation and load. This gap can be filled with proper control, monitoring and
coordinating the distribution components at power sector. In this view, Automation of power
distribution system has increasingly been adopted by power utilities worldwide in recent years.
As part of its efforts to provide a more reliable supply to the customer and to enhance operational
efficiency. The automation of the power system can be achieved by SCADA. It is a boon to the
automation concept of dynamic technology. SCADA refers to “SUPERVISORY CONTROL &
DATA ACQUISITION”.
Karnataka Power Transmission Corporation Limited (KPTCL) has undertaken steps to automate
existing substation and new substation by use of most advanced controlling and monitoring
technology ABB SCADA. Project was conceived in the year 2002, tenders floated in the year
2006 and project awarded to M/S ABB in December 2006. 220/110/11kV Receiving Station
Bijapur near Shivgiri Ukkali road and 110/11kV Receiving Station Bijapur at City were some of
the substations automated in this project.
Monitoring, controlling and coordinating the distribution equipments and trouble shooting at
fault are challenging task for engineers. These aspects make the power and energy system
engineers to know more about controlling of power system. In this view training has been taken
under Karnataka Power Transmission Corporation Limited (KPTCL) at Bijapur.
Karnataka Power Transmission Corporation Limited (KPTCL), presently with the help of
SCADA covers major generating stations and Independent Power Producers (IPP), receiving
stations ranging from 33kV to 400kV, collects data from all feeders from 11 KV to 400 KV,
upgrades information to Load Despatch Center (LDC). Real time data acquisition from all
interface points by SCADA, helps to perform energy billing, energy audit and Availability Based
Tariff (ABT) functions, and Sub-system to perform Open Access operations.
SCADA IN KPTCL
1. Introduction
Karnataka Power Transmission Corporation Limited is mainly vested with the functions of
Transmission of power in the entire State of Karnataka. To transmit and distribute power in the
State, it operates nearly 1042 sub-stations over 32,000 km of transmission lines with voltages of
66 KV and above. The 33 kV substations are owned and operated by the ESCOMs. To monitor
and control all substations remotely, KPTCL has undergone substation automation through
SCADA.
Substation Automation (SA) is a system to enable an electric utility to remotely monitor, control
and coordinate the distribution components installed in substation. High speed microprocessor
based Remote Terminals Units (RTUs) or Intelligent Electronic Devices (IEDs) are used for
substation automation and protection. These RTUs or IEDs are installed in strategic locations for
collection of system data and automatic protection of substation equipment [1]. Considering
economic aspect, instead of replacing all existing substation equipment for purpose SCADA,
KPTCL provides Remote Terminal Unit (RTU) at old substation for remote control. Thus at
110/11 kV substation Bijapur installed with RTU 560A. For new substations Substation
Automation System (SAS) is being used for automation. Thus at 220/110/11kV substation near
Shivgiri has both remote and local control by installing ABB’s IED 670. Data communication
protocols used for 110 kV substation are MODBUS, RS485, RS232, and for 220kV substation
are IEC61850, Optical Fiber Cable (OFC). Information collected from substations is
communicated through VSAT to Master Control Center (MCC).
In this training report effort has been made to explain SCADA implementation at 110/11kV and
220/110/11kVsubstations as both are different. Report consists of about SCADA technology,
SCADA connections at substation, equipment details used for SCADA, communication
protocols. Brief explanation on operation and working of Load Despatch Center is also included
in report. Thus concluding that SCADA has provided real time data acquisition, data sharing &
analysis, supervisory control, remote operation, reduces man power, helps in decision making,
and access to risky areas and multiple controls from single point.
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2. SCADA technology
The ability to perform operations at an unattended location from an attended station or operating
center and to have a definite indication that the operations have been successfully carried out can
provide significant cost saving in the operation of a system. This is exactly what is achieved
through the SCADA system. A formal definition of SCADA system, as recommended by IEEE,
is “A collection of equipment that will provide an operator at a remote location with sufficient
information to determine the status of particular equipment or a process and cause actions to take
place regarding that equipment or process without being physically present”.
2. 1. Common system components:
A SCADA System usually consists of the following subsystems [2]:
i. A Human Machine Interface (HMI) is the apparatus which presents process data to a
human operator, and through this, the human operator monitors and controls the
process.
ii. A supervisory (computer) system, gathering (acquiring) data on the process and
sending commands (control) to the process.
iii. Remote Terminal Units (RTUs) connecting to sensors in the process, converting
sensor signals to digital data and sending digital data to the supervisory system.
iv. Programmable Logic Controllers (PLCs) used as field devices because they are more
economical, versatile, flexible, and configurable than special purpose RTUs.
v. Communication infrastructure connecting the supervisory system to the RTUs.
2. 2. Typical SCADA system:
A typical SCADA system as shown in figure 1, is comprised of both software and
hardware components [3].
i. SCADA software, typically running on a plant-based computer, acts as a human-
machine-interface (HMI) to the control system. The SCADA software reads data
from the controller module, displays the data in a timely manner and optionally logs
the data to a local hard drive. SCADA software can also be configured to generate
and log alarms based on user-defined alarm conditions as well as send command
messages to the CPU module.
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ii. SCADA hardware includes a central processing unit (CPU or controller module) that
receives data from field sensors, determines control actions based on user-
programmed logic, and then sends control commands to field devices.
Fig 1: A Typical SCADA System [3]
2. 3. SCADA for Power Transmission:
Present day power systems have large interconnected networks. The success of the recently
evolving electricity market structure will heavily depend on modern information systems and
online decision tools. Maintaining system security, reliability, quality, stability and ensuring
economic operation are the major operating concerns. Online monitoring, operation and control
of the modern day power systems have become impossible without computer aided monitoring
& dispatching systems. The basic requirement to fulfill these needs is SCADA.
SCADA provides open architecture rather than a vendor controlled proprietary environment. It
interfaces hardware and software, and it includes functionality such as trending, alarm handling,
M.Tech in Power and Energy System, EEED, BEC, Bagalkot. 3
Computer
Field Sensors
Field Devices
Power
Supply
Controller Module (CPU)
AIN
Module
DIN
Module
AOUT
Module
DOUT
Module
SCADA HMI Software on PC
Control Hardware
Communication Protocol
SCADA IN KPTCL
logging archiving, report generation, and facilitation of automation. Thus SCADA has been used
has powerful tool for power system automation, that refers to automatic switching, regulating,
controlling, logging, protection etc. of electric power flow without human intervention.
2. 4. SCADA Manufactures:
i. Modicon (Telemecanique) Visual look
ii. Allen Bradly : RS View
iii. Siemens: win cc
iv. Gefanc:
v. KPIT : ASTRA
vi. Intelution : Aspic
vii. Wonderware : Intouch
2. 5. SCADA Benefits:
i. SCADA increases reliability.
ii. It helps in forecasting accurate demand supply management.
iii. It reduces maintenance cost and helps in monitoring of process at remote place.
iv. It reduces human influence and errors.
v. It assists operator for faster decision making.
vi. It helps in automated meter reading and easy fault diagnosis.
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3. Brief description of SCADA Project in KPTCL
Prior to implementation of Integrated Extended SCADA (IES) project KPTCL had total of 63
RTUs covering 220 kV, 400 kV and generating stations, only main control systems and 21 RTUs
were acquired. KPTCL set up its own VSAT network to provide the communication back bone
during 1998, the uptime of VSAT network since then is greater than 99.95% [4].
Integrated Extended SCADA (IES) project was implemented to provide reliable, uninterrupted,
quality power to the consumers and provide secure operation and control of the Power System in
the country leading to ‘GRID DISCIPLINE’. For speedy and efficient decision-making and for
running the power system at maximum economy IES project was implemented.
3.1. Objective of IES Project:
i. A common integrated solution to cater to the network extending to the entire state of
Karnataka – covering 854 Stations of Transmission, Generation and Distribution
companies in the I phase.
ii. Integrated Solution for Energy Auditing, Energy Billing and Availability Based Tariff
to meet regulator’s requirement.
iii. Integration of all Sub-station and Generating Station Automation systems.
iv. Data to all ESCOMs for scheduling and monitoring.
v. Facilitate Integration to other “down the line” Distribution Systems of ESCOM.
3.2. Features of IES Project:
i. SCADA to cover receiving stations ranging from 33kV to 400kV.
ii. SCADA to cover Major Generating stations and IPPs.
iii. Data from all feeders from 11 kV to 400 kV.
iv. Area Load Despatch Centre for Six Transmission Zones.
v. Distribution Control Centre for five ESCOMs.
vi. Upgradation of State Load Despatch Centre.
vii. EB/EA/ABT system to perform Energy Billing, Energy Audit and Availability Based
Tariff functions.
viii. Sub-system to perform Open Access operations.
ix. Real time Energy Data Acquisition from all Interface points.
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x. Energy Management System and Distribution Management System.
xi. Privately owned VSAT Hub and network with leased bandwidth from INSAT 3A
xii. Disaster Recovery Hub.
3.3. Project information:
i. Project conceived in the year 2002.
ii. Draft specifications prepared in-house from 2002 to 2005.
iii. Specifications vetted by an Expert Committee including members from IISc, CPRI
and experts from the field.
iv. Tenders floated in the year 2006.
v. Project awarded to M/S ABB in December 2006.
vi. Project period : 24 months
vii. Project cost : Rs.186 crores
viii. BESCOM share : Rs.11.2 crores
3.4. IES Components:
i. SCADA Remote Terminal Unit (RTU) ABB Model 560
ii. HP make Servers for SCADA, Data EMS and DMS
iii. HP Work stations for Engineering and Operation
iv. HP make Server for Dispatcher Training Simulator
v. Multi Frequency Time Division Multiple Access (MFTDMA) communication Hub
for VSAT operation of Gilat Israel
vi. Network Manager SCADA and EMS software of ABB Sweden
vii. Oracle 11i for database
viii. Windows XP and MS office 2003 for Work stations
ix. IEC 104 protocol for RTU- Control centre communication
x. Meter Interface card of ABB for Energy meter integration.
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xi. Cisco routers for communication interfaces
xii. Bandwidth from INSAT 3A
xiii. OFC solution from BSNL.
3.5. KPTCL SCADA System Architecture:
Figure 2 shows SCADA system architecture at KPTCL. It consists of 16 control centers, which
includes the Main Control Centers (MCC), a Disaster Recovery Centre (DRMCC), Area Load
Despatch Centers (ALDC) for the Transmission Zones and Distribution Control Centers (DCC)
for the ESCOMs.
Fig 2: SCADA System Architecture at KPTCL [4].
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List of control centers:
i. Main Load Despatch center (LDC) – 1 No.
ii. Master Control Centers (MCC) – 2 No. i.e., MCC 1 and MCC 2.
iii. Disaster Recovery Master Control Center – 2 No. i.e., DRMCC 1 and DRMCC 2.
iv. Area Load Despatch Centers (ALDC)for the Transmission Zones – 6 No. they are
a. Bangalore Transmission Zone (BNG TRZ).
b. Tumkur Transmission Zone (TMK TRZ).
c. Mysore Transmission Zone (MYS TRZ).
d. Hassan Transmission Zone (HSN TRZ).
e. Bagalkot Transmission Zone (BGK TRZ).
f. Gulbarga Transmission Zone (GLB TRZ).
v. Distribution Control Centers (DCCs) for the ESCOMs – 5 No. they are
a. Bangalore Electricity Company (BESCOM).
b. Mysore Electricity Company (MESCOM).
c. Hubli Electricity Company (HESCOM).
d. Gulbarga Electricity Company (GESCOM).
e. Central Electricity Company (CESCOM).
All the Transmission RTUs communicate to MCC-1 & Distribution RTUs communicate to
MCC-2. The total system is configured with 72 servers and 115 operator workstations.
Communication is on a owned VSAT HUB and Leased Lines for Inter control Centre
Communication [4].
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4. Study of SCADA Implemented Substations at Bijapur
According to features of Integrated Extended SCADA project, KPTCL covers all receiving
substation ranging from 33 kV to 400 kV. 110/11kV Bijapur receiving station at City was one of
old station to acquire data, monitor and to control remotely SCADA was implemented at this
station under IES project I phase. 220/110/11kV substation Bijapur near Shivgiri is newest
station which was fully automated with SCADA for remote as well as local control under IES
project. Implementation, working, equipment used at both station are different, hence detailed
study of both stations is described in this section.
4.1. CASE I – 110 kV City Sub station
Location
State : Karnataka
City : Bijapur
Area : Near RTO, Ibrhampur
4.1.1. Over view of substation
110 kV substation is situated at Ibrhampur near RTO office Bijapur. It receives power supply from 220
kV substation Bijapur (double lines) and distribute power to local Bijapur areas such as JalNagar, Jumma
masjid etc (feeders).
4.1.2. SCADA Implementation:
Under Integrated Extended SCADA (IES) Project, adaptation works were basically carried out
on the oldest substation as old as 50 years. Adaptation works for 600 sub station was carried out
and completed in a record time of one year. During this 110 kV City substation Bijapur was
undergone, as it is old substation there was need to acquire data from existing equipment.
Renewing all equipment or replacing old equipment by new equipment will increase cost, it is
not economical also. Thus KPTCL took step to automate existing substation by installing
RTU560A SCADA for automation and send all information to Master Control Center (MCC).
Figure 3 gives general block diagram of implementation of SCADA at all old substation in that
110/11kV substation Bijapur was one of substation.
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Fig 3: General Block diagram of Implementation SCADA
According to abbreviation of SCADA, Supervision, Control And Data acquisition are the main
tasks to be carried out at every substation. Supervision - of the incoming line, Control and Relay
Panels (C&R panel), Control - Switch gear and data acquisition - such as Voltage (phase),
current (phase), active and reactive power, frequency etc. Table 1 gives information about
parameters, input and output, relation of these with SCADA at 110/11 kV substations.
Table 1: SCADA, I/O and parameters used at 110/11 kV substation.
SCADA Supervision Control Data Acquisition
Input/Output Digital input Digital output Analog input
Observation • Status indication
• Control & relay panel
• Switch Gears
• CT & PT
• Measured
value such as
voltage current
etc.
Supervision, Control and Data Acquisition at 110 kV City station Bijapur is done by installing
ABB’s RTU 560A which consists of all facilities that required for automation.
About Remote Terminal unit (RTU)
The RTU connects to physical equipment. Typically, an RTU converts the electrical
signals from the equipment to digital values such as the open/closed status from a switch
or a value, or measurements such as pressure, flow, voltage or current. By converting and
sending these electrical signals out to equipment the RTU can control equipment.
M.Tech in Power and Energy System, EEED, BEC, Bagalkot. 10
Existing
Substation
110/11 kV
SCADA
RTU 560A
Mater Control
Center (MCC)
SCADA IN KPTCL
4.1.3. SCADA Equipments to Substation:
At 110/11kV city substation Bijpaur, consists of the following SCADA equipments. They
are:
i. RTU 560A along with IF panel.
ii. VSAT
• Antenna,
• IDU,
• 8 port switch ,
• telephone
iii. 2 kVA UPS (Power One make) along with
• 8 No of 100Ah, 12V cells
• Battery stand
• ACDB
I. RTU 560A :
Transmission and distribution networks are frequently being expanded, often resulting in
more complex networks. The task of monitoring and controlling the energy transportation
in order to achieve an economical operation. ABB’s solution for transmission and
distribution application requirement is Remote Terminal Unit system RTU560. Within
the RTU560 family the communication unit and the I/O board family is a hardware
system based on standard European format cards. To meet the requirements for typical
medium stations with only some communication links on one side and large or modern
stations with a higher number of IEDs on the other side, the RTU560, based on European
format cards, is available in two versions [5]:
RTU 560A for configurations with higher demands on communications links. The
parallel wired process interface is still part of the configuration.
RTU 560C for typical stations with a parallel wired process interface and some
communication links only.
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SCADA IN KPTCL
Fig 4: ABB RTU560A Panel at 110/11 kV substation.
The SCADA RTU560A as sown in figure 4 is small ruggedized computer, which provides
intelligence in the field. It allows the central SCADA master to communicate with the field
instruments. It is stand alone data acquisition and control unit. Its function is to control process
equipment at the remote site such as to open or close the circuit breakers. It acquires data from
the equipment and transfers the data back to the central SCADA system.
Features of RTU 560A:
• 4 serial communication interfaces for host communication
• 32 MB Flash Memory
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• 8 MB RAM
• Web Server
• PC104 module with CPU 486/66MHz
• PLC capable
Components of RTU 560A:
Fig 5: Components of RTU 560A.
Figure 5 shows components of RTU 560A, it consists of Basic rack (top rack) with CPU and
communication ports, Extension rack 1 (2nd rack) with Digital Input card (DI) Analog Input card
(AI) and Analog Output card (AO). Digital Output card (DO) at Extension rack 2 (3 rd rack) and
each rack is supported by separate power supply cards. For load alarm annunciation, there is rack
called SCADA annunciation panel. Table 2 gives details of components and their function.
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Table 2 : Details of RTU 560A component.
Sl No. Components Quantity Function
1 Multifunction Transducer (MFT) 30 30 no. of bays data can be
collected.
2 Digital Input Card (DI card) 8 Each card supports 16 digital
inputs.
3 Digital output Card (DO card) 5 Each card supports 16 digital
outputs.
4 Analog Input Card (AI card) 3 Each card supports 8 inputs.
(DC Voltage, Tap position…)
5 Analog Output Card (AO card) 1 2 linear control
6 Digital Output Relays 80 40 breakers can be controlled.
(One relay for trip, one for close )
7 Meter Interface card 1 For acquiring ABT Energy meters
located at IF points
8 Communication Card 2 Each having 4 ports for
communication.
9 AC-DC Converter 2 For providing DC power supply
to rack (48 V).
10 SCADA Control Annunciator 1 Provides alarm for operator.
11 Optocoupler 3 To isolate voltages (110V dc &
48V).
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Description of RTU 560A components:
1. Multifunction Transducer (MFT): A Transducer is a device, usually electrical,
electronic, or electro-mechanical, that converts one type of energy to another for the purpose of
measurement or information transfer. At substation multifunction transducers are used change an
electrical quantity such as voltage, current, power or frequency into a proportional dc output.
Fig 6: Multifunction transducer.
Multi-function transducers are used for measuring wide range of analog values in a 3-phase 4-
wire and 3-phase 3-wire balanced and unbalanced systems. Figure 6 shows MFT used at 110/11
kV substation, it can measure 96 electrical parameters from single transducer. MFT with latest
technology provides combination of high accuracy and comprehensive functionality. They have
compact structure and MODBUS RTU support for remote interrogation of energy and