ELECTRICAL DESIGN REPORT - WordPress.com · GREENGATE DEVELOPMENT ELECTRICAL DESIGN REPORT: FEB 2016 GKW CONSULTING 3 | P a g e 1. Project Overview 1.1 Project background Greengate

GREENGATE DEVELOPMENT,

GAUTENG

ELECTRICAL DESIGN REPORT

Client: Afroprop Natal Mr Glen Dames 5 Torlage Street, New Germany Telephone 031 705 4490; 082 653 5955 [email protected] Electrical Consulting Engineers: GWK Consulting Mr Gary Willson 14 Steele Rd, Pietermaritzburg 3212 082 561 1051

GREENGATE DEVELOPMENT ELECTRICAL DESIGN REPORT: FEB 2016 GKW CONSULTING

2 | P a g e

TABLE OF CONTENTS

No. Page No.

1 Project background 3

2 Planning and Design 5

3 Scope of work 9

4 Work Breakdown structure 10

5 Specifications 11

6 Test commissioning 15

7 Constructability 15

8 Cost breakdown 16

9 ANNEXURES 17

A BI LL OF MATERIALS


3 | P a g e

1. Project Overview

1.1 Project background

Greengate development is situated as in figure 1 between Eskom Dalkeith and Sandpit

substations. The development consists of 19 usable sites as shown in table 2 with the largest

being Spar on Erf 18 and 20. The development will entail the establishment of commercial,

light industrial and residential loads. Figure 2 shows the approved layout plan.

Figure 1: Geographic overview of Greengate Development

Figure 2: Development layout drawing of proposed sites

Greengate dev Eskom 88kV line


4 | P a g e

Table 1 shows the load phasing of the development over a five year period with table 2

showing the details of the magnitude of power estimated for each site as in figure 2.

Table 1: Load phasing of total development

Load (MVA) Year

Phase 1 500kVA 2016

Phase 2 2MVA 2017

Phase 3 7MVA 2019

Table 2: Load phasing of each individual site

Erf nos.

Size (m2) Zoning Number of units

Estimted ADMD (kVA)

Total network

load (kVA) Coverage

Watts per m2

Diversity Network

coincidence

1 8694 Commercial 1 292 292 60% 80 0.7 219.09

2 8787 Commercial 1 295 295 60% 80 0.7 221.43

3 20578 Commercial 1 691 691 60% 80 0.7 518.57

4 19448 Light Industrial 1 245 245 60% 30 0.7 183.78










14 11428 Residential - 70 units / ha 40 5 200

80.00

15 22447 Residential - 70 units / ha 79 5 395 158.00



18/201 232362 Light Industrial 1 2928 2928 60% 30 0.7 1903.04


Total Load kVA 7053 kVA 4788.80

1SPAR development


5 | P a g e

2. Planning and Design

2.1 Network overview

2.1.1 Eskom infeed

Greengate development is approximately 3.6km from Eskom Dalkeith 88/11kV substation.

Dalkeith S/S reticulation voltage is 11kV and the following fault levels were given by Eskom

Network Planning, Gauteng operating unit.

Table 3: Fault levels at Dalkeith S/S 11kV busbar

2015 Fault Levels (11kV)

Single Phase (kA) Three Phase (kA)

0.248 19.81

The cable infeed from Dalkeith substation has been selected to be 1 x 300mm² Aluminium

cable due its short circuit current rating of 28kA and current capacity rating of 8MVA

underground. Aluminium cable has been chosen due to the theft in the area. Dalkeith

substation is currently loaded at 75% and the forecast obtained from Eskom Gauteng

Operating unit, Network planning department indicates that the substation is unfirm and a

project to change the existing 88/11kV 2x20MVA transformers to 2x40MVA transformers will

be implemented. Figure 3 shows the load forecast of Dalkeith S/S obtained from the planning

department.

Figure 3: Load forecast of Dalkeith Substation

An 11kV 800A feeder breaker is required for the interconnection between Dalkeith substation

and Greengate development. The existing Eskom substation single line diagram indicates


6 | P a g e

existing spare breakers. Also, the interconnection of 3.7km cable is proposed to be a self-build

by the developer. The proposed and preferred cable route is shown in figure 4a.

Figure 4a: Preferred cable route for Greengate infeed supply

Figure 4b: Alternate cable options for Greengate infeed supply

Three cable routes have been identified as shown in figure 4b. The preferred route shown in

figure 4a falls in the proximity of a wetland which is yet to be confirmed in its significance.

3.55kmm

3km

3.59km


7 | P a g e

2.1.2 Greengate development internal design

The internal cable reticulation is designed with figure 4 constraints and as such possible

routes from Dalkeith S/S traverse the development entrance as in figure 5a. Hence the cable

network is designed accordingly. Two circuits provide 100% redundancy in the development.

Both use 300mm² Al cable to the largest load, Spar (2B), with 185mm² cables creating an

electrical ring (approximately 2.27km) for any internal network contingency. Switching points

are created at 1C and 2B ring main units respectively.

Figure 5a: Internal prelim design

From Eskom Dalkeith S/S

RMU 2R-1B

RMU 3R

Minisub

300mm sq

185mm sq

175m

292m

1060m

1A

1C

2B

2A

1H

1070m 230m

32m

Cable Loop

1F


8 | P a g e

Figure 5b: Electrical single line diagram


9 | P a g e

Figure 6: Internal simulation model

Figure 7: Internal voltage profile during full load – normal and contingency


10 | P a g e

Table 4 and 5 show the simulated three phase and single phase fault levels for the above

model in figure 6. Although the fault level at Dalkeith S/S is relatively high, cumulative

downstream impedance limits the level to 10kA at Greengate development. The cable thermal

limits shown in table 5 indicate the most heavily loaded feeds in the internal reticulation. With

the limitation of 6MVA for 185mm² cables, the load is well distributed. Using a network

coincidence of 0.75 and assuming the worst case demand of 4MVA from the Spar load, the

total network load approximates to 6.2MW, 77% of the cable rated infeed.

Table 4: Voltage and MV fault levels at each switchgear 11kV point

Table 5: Cable thermal limitations of internal MV distribution

Cable interconnectors Loading

(MW, %)

3725m 300mm Al 6.2MW 77.00%

230m 300mm Al 2.2MW 27.10%

292m 300mm Al 3MW 37.10%

3. Scope of Work

The electrical works for Greengate development will entail the installation of MV cabling and

switchgear only. The ownership of the equipment, once energised, will be transferred to

Eskom Gauteng operating Unit. It is therefore imperative, for all equipment supplied by the

developer, that Eskom standards and specifications are to be strictly adhered to. Withstanding

this, the SOW follows namely:

Dalkeith S/S NB

• Install 11kV feeder breaker and cable scheme protection;

• Lay 1 x 3.9km of 300mm2 Al, XLPE cable;

11kV points Voltage Fault level

p.u 3 phase 1 phase

11kV BB 1.03 19.89kA 0.272kA

1A RMU 3R 1.01 9.99kA 0.268kA

1C RMU 3R 1.01 9.54kA 0.268kA

1H Minisub 1.01 7.231kA 0.266kA

2B RMU 2R-2B 1.01 9.37kA 0.268kA

2A Minisub 1.01 9.93kA 0.268kA


11 | P a g e

Greengate development internal distribution

• Lay 2.25km of 185mm2, Al, XLPE cable

• Lay 572m of 300mm2, Al, XLPE cable;

• Install 2 x (3R) RMU’s

• Install 1 x (2R-2B) RMU;

• Install 2 x (500kVA) minisubs;

• Install Streetlights and associated lv cabling (local munic)

4. Work Breakdown Structure (WBS)

Circuit 1

1A - Terminate 300mm2 cable from Dalkeith S/S into 3-way RMU;

1B - 300mm2 cable to be looped for RMU provision;

1C - Install 3-way RMU, terminating the 300mm2 cable in and terminating 185mm2 out

the RMU; An additional 300mm2 cable will be terminated out of the RMU to RMU at

2B

1D - 185mm2 cable to be looped for RMU provision;

1E - 185mm2 cable to be looped for RMU provision;

1F - 185mm2 cable to be looped for RMU provision;

1G - 185mm2 cable to be looped for RMU provision;

1H- Install 500kVA Type B Minisub, terminating the 185mm2 cable into the minisub;

Circuit 2

2A- Install 500kVA Type B Minisub, terminating the 300mm2 cable from 1A into the

minisub;

2B- Install 2R-2B RMU, terminating the 300mm2 cable in and out the RMU; breaker 1

to feed Spar and breaker 2 to terminate 185mm2 cable to minisub 1H

The WBS follows on from the SOW where electrical works of high importance are highlighted

to ensure construction. The WBS is to be read in conjunction with Annexure C of the detailed

design report.

5. Specifications

This project shall be carried out fully in accordance with this Detailed Project

Specification, the referred Technical Specifications and the relevant drawings and

documentation governed by all Eskom standards.


12 | P a g e

This project shall conform in all instances to the Occupational, Health and Safety Act,

and regulations, (Act No. 85 of 1993) and any amendments thereto, including the

Safety Specification in terms of Regulation 4 thereof.

In terms thereof, the Contractor is to provide a Health and Safety Plan to comply with

the Occupational, Health and Safety Act and Regulations, (Act No. 85 of 1993), based

upon but not limited to the Health & Safety Specification in Part 1.2.7.

5.1.1 Cable Installation

• Excavate cable trenches according to Eskom standard DDT-0854. Beware of other

services in close proximity of new cable route;

• Barricade all excavations, as per Eskom standard TQAPP043, Minimum

Requirements for the Barricading of Project Site Excavations. Where

excavations are in close proximity to public roads, road traffic warning signs

must be erected to warn motorists of the work in progress;

• Lay 11kV Al XLPE MV cable according to SANS 10198 code of practice and

Eskom standard DST_34-1175 General Information & Requirements for MV

cables;

• Backfill and compact all excavations according to Eskom standard DDT-0854, and

clear the surrounding area of all waste material and dispose in approved dump site;

• Bedding and blanket soil to be sieved with sieve of 12mm mesh size;

• Where cable trench runs parallel to and under the road surface, it shall be positioned

at least 200mm from the edge of the kerbing or tarred road surface;

• Concrete cable slabs, DDT-8076, must be installed under road crossings, 250mm

above MV cable if no concrete ducting used;

• Where road surfaces are tarred, tar cutting machines must be used;

• Road surfaces must be backfilled to relevant road agency specifications;

• Install concrete cable markers at regular intervals on straight runs, at all bends, on

either side of road crossings and joints;

• All new 11kV cable work must be prepared and fully installed before the outages.

Special note:

• Cable trenches must be inspected by the appointed Clerk of Works for compliance to

DDT-0854, before the cable is installed.

• Cable laying must be done in the presence of the appointed Clerk of Works. The

COW must be notified in advance (a minimum of 5 days), before cable laying


13 | P a g e

commences.

• The COW must inspect the cable laying process at the following intervals:

➢ After cable trench excavations have been completed.

➢ After bedding soil has been prepared.

o During cable laying and blanket soil compaction by hand tools.

o After cable warning tape has been installed.

o After final backfill has been compacted to 90% MOD ASHTOO (in layers of

300mm).

o After rehabilitation of all disturbed ground has been completed.

• All MV cable joints/bends to be indicated using concrete markers with a plate indicating

size and voltage of the incoming and outgoing cables and equally spaced 100m apart and

sticking above natural ground level by 275mm as per DDT 8012 and DST 34-1175.

• All MV Terminations above 95mm2 into RMU’s must use Trifurcating Kits – DDT 8006

& DDT 8004.

5.1.2 RMU Installation

• Select a suitable position for the new 3R and 2R-2B RMU’s, on the same side of the

road as per the above cable installation and directly in line with the marked cable

ducting;

• Prepare ground and install new pre-cast concrete plinth for new 3-way and 2R-2B

RMU’s according to Eskom Engineering Instruction EI-042-MVG Procedure for

Installation of Plinths for Ground-Mounted Kiosks;


Requirements for the Barricading of Project Site Excavations;

• Install "Flash band" sealant strip DDT-8029 between RMU base and the top surface

of the plinth;

• Install and secure the new 3-way and 2R-2B RMU’s on the new pre-cast concrete

plinth, with Stainless Steel Bolts;

• Install all RMU MV earthing, according to Eskom standard DDT-0830 & DDT-0855.

Check MV earth electrode resistance is 30 ohm or less;

• Arrange for and test the new RMU’s on site once installed in position;

• Terminate all MV cables into new 3-way and 2R-2B RMU’s, with 11kV indoor cable

terminations DDT-8005/6 and unscreened separable connectors DDT-8016 and

connect to the new RMU’s MV terminals;


14 | P a g e

• Fill cable entry cavity with sifted soil and screed seal with weak cement mix as per

Eskom Engineering Instruction EI-042-MVG Procedure for Installation of Plinths

for Ground-Mounted Kiosks;

• Arrange and perform all necessary commissioning tests and protection settings on

the new RMU’s and MV cable terminations, prior to energising;



• Install new labelling on each RMU as per the memo’s and as per Eskom standard

DISASAAN0, Standard for the labelling of Substations and Networks.

5.1.3 Minisub Installation


Requirements for the Barricading of Project Site Excavations;

• Prepare ground and install new pre-cast concrete plinth for new Type B mini-

substation to the allocated site, according to Eskom Engineering Instruction EI-

042-MVG Procedure for Installation of Plinths for Ground-Mounted Kiosks in

Eastern Region;

• Caution must be exercised when excavating in close proximity of the existing mini-

substation not to expose or damage the existing MV and LV cables;

• Install MV and LV Earthing according to Eskom standard DST_34-1175,

Distribution Standard, Part 22, Section 0: General information and requirements

for medium voltage cable systems, and Eskom standard DDT-0830 & DDT-0855;

• Check MV earth electrode resistance is 30 ohm or less;

• Install an equi-potential earth loop around the plinth, according to Eskom standard

D-DT-0865 required for operator safety;

• Install "Flash band" sealant strip DDT-8029 between Mini-substation base and the top

surface of the plinth;

• Install and secure the 500kVA 11kV/400V Type B mini-substation on the new plinth,

with Stainless Steel Bolts;

• Terminate all new MV cables with 11kV indoor cable terminations DDT-8005/6 and

unscreened separable connectors DDT-8016 and connect to the new mini-substation

RMU MV terminals;

• Fill cable entry cavity with sifted soil and screed seal with weak cement mix as per

Eskom Engineering Instruction EI-042-MVG Procedure for Installation of Plinths

for Ground-Mounted Kiosks in Eastern Region;


15 | P a g e

• Arrange for and test the mini-substations on site once installed in position;

• Arrange for Eskom EDFS to perform all necessary commissioning tests on the mini-

substations and new MV cable terminations, prior to energising;



• Install all new labelling on each mini-substation as per the memo’s and as per Eskom

standard DISASAAN0, Standard for the labelling of Substations and Networks;

• Check and record phase rotation on all LV circuits leaving mini-substation;

• Connect all LV cables to LV fuses in the LV cubicle of the new mini-substation. Note:

should the cables be too short, then a section sufficiently long with 2m slack, to reach

the LV fuse terminals, must be jointed to the existing cables.

5.1.4 Street lighting Installation

• To be spec’d, installed and maintained by the property owner’s association for the

development.

6. Tests and commissioning:

The following electrical tests shall be successfully completed as part of the

commissioning process:

• Voltage level tests

a. The voltage level of the installation shall be measured and recorded;

• Test to ensure that live and neutral connections have not been reversed

a. This test shall be done using a single probe neon-wired screwdriver that lights

up if a live connection is touched. Mandatory test to be carried out:

i. Install a temporary earth spike of at least 300 mm, alongside the street

lighting pole. Connect a lead wire to the earth spike and measure the

voltage between the temporary earth and the luminaire earth and

neutral. If any reading is recorded, the connection of the live and

neutral conductors may be wrong, and the supply shall be checked. In

this case, the live and neutral connections shall be changed over and

the test shall be repeated;

ii. If a voltage is measured once the live and neutral terminals have been

changed, a qualified person who can solve the problem, shall be


16 | P a g e

requested to investigate.

7. CONSTRUCTABILITY

• Cable and MV switchgear to be laid prior to outage request;

• Eskom COW or Eskom CNC to valid and validate the switchgear and cable

installation prior to outage;

• During outage period, the 1 X 300mm2 cable will be terminated into the Dalkeith

substation 11kV indoor board.

8. COST BREAKDOWN

TOTAL PROJECT VALUE

Materials (M) R 8,180,830.36

Transport (T) R 327,233.21

Labour + Buy Out materials(L) R 4,070,758.88

Commissioning (C) R 37,736.47

Sub-Total 1 (M,T,L,C) R 12,616,558.92

Engineering Design (ED) R 504,662.36

Survey (S) R 63,082.79

Clerk of Works (CW) R 33,880.00

Project Management (PM) R 251,576.45

Sub-Total 2 (ED,S,CW,PM) R 853,201.60

Total R 13,469,760.52


17 | P a g e

9. ANNEXURES

ANNEXURE A - BILL OF MATERIALS

ANNEXURE B- SINGLE LINE DIAGRAM ANNEXURE C - SURVEY DRAWING ANNEXURE D- SAG AND TENSION CHARTS

ANNEXURE E- PROJECT RISK ANALYSIS ANNEXURE F- STANDARDS AND SPECIFICATIONS ANNEXURE G- PROJECT CHECKSHEETS

ELECTRICAL DESIGN REPORT - WordPress.com · GREENGATE DEVELOPMENT ELECTRICAL DESIGN REPORT: FEB 2016 GKW CONSULTING 3 | P a g e 1. Project Overview 1.1 Project background Greengate

Documents