OptiPower was responsible for the full turn-key construction of 132kV/11kV Klapmuts Substation.

This involved the following work.

Access Road

  • Cleared 650m2 vegetation and discarded at approved dumping site.
  • Cut 195m3 of topsoil and discarded at approved dumping site.                                                                    
  • Import and place 100m3 G6 material.
  • Import, place and compact 100m3 G5 material to 93% MOD AASHTO MOD at OMC. 


  • Cleared 12500m² vegetation and discarded at approved dumping site.
  • Cut to spoil 23950m³ in situ soil and discarded at approved dumping site.
  • Roadbed preparation. Ripped 100m³ in situ soil and compacted to 90% MOD AASHTO MOD at 2% OMC.
  • Replaced 32750m³ in-situ ground with G5 quality ground and compacted in 150mm layers to 93% MOD AASHTO at OMC.
  • Levelling 11310m² of platform with 1:150 slope.

Terrace Road

  • Supplied and installed 300m precast channel edge curb.(SABS927 Figure 13)
  • Imported and compacted 125m³ G4 material surface layer to 95% MOD AASHTO with a UCS of 5Mpa.
  • Supplied and installed 8off 160mm x 6m PVC pipes 1m under yard road, 300mm apart.
  • Supplied and installed control cable trenching at terrace road crossing, including 3m x 5.5m x 0,15m concrete road cover.

Surface water drainage

  • Excavated, supplied, installed and constructed 360m sub-soil drain.
  • Excavated, supplied, installed and constructed 2 concrete headwalls.
  • Excavated, supplied, installed and constructed 20m² ,15Mpa concrete filled Geocell lined gutters. 
  • Excavated, supplied, installed backfilled 160m, 150mm concrete drainage pipes on both sides of internal road. 
  • Excavated, supplied, installed and constructed 75m2 interlock paving around building.

Main Earth grid

  • Installed 4580m, 10mm round copper earth grid.
  • Installed 380m, 50mm x 3mm flat copper earth tails to main earth grid.
  • Installed one, sacrificial anode. 
  • Tested main earth grid to true earth.

Control/Switchgear Building

  • Construct a 199m² Control/Switchgear Building.

Equipment Foundations

  • Install 90, Equipment Foundations, two Transformer bund walls and one Transformer oil holding dam & oil trap with a total of 460m3 25MPa Reinforced Concrete

Supplied and placed a total of 1040m³, 25mm Yard stone.

Supplied and installed 100tons of Galvanised Steelwork 

Primary Equipment Installed

  • Two 20MVA Transformers 20MVA 132/11 kV OLTC
  • Five, 132 kV Circuit Breakers 3150A 40 kA 3P 110VDC 31mm/kV (ABB)
  • 12, 132 kV Isolators 2500A 25kA H/O 31mm/kV
  • 18, 132 kV Current Transformers 2500A 25kA 2P2M2B(1600/1) 31mm/kV 
  • Six, 132kV/110V 100/50VA 31mm/kV Voltage  
  • Two, S/CL 66 kV MCOV 48 kV 31mm/kV
  • Six, S/CL 11 kV MCOV 12 kV 31mm/kV
  • Two, VT 3PH 11 kV/110V 50VA CL 0.2 Panels
  • Two, 11 kV 2500A 25kA TRFR Panels
  • Six, 11 kV 800A 25kA FDR BKR Panels 
  • One, 11 kV 2500A 25kA B/Sect BKR Panel

Secondary Plant Installed

  • One, 132 kV Bus zone protection panel
  • One, 132 kV Bus zone Protection panel
  • Two, Transformer Control/Protection panels
  • Two, 132 kV Incomer Line Control/Protection panels
  • Four, Statistical and Check Metering Panels.
  • 11, Yard Junction Boxes.

Auxiliary Equipment Installed

  • One, AC/DC panel and battery charger
  • One, 52 Cell Battery Bank
  • One, Remote Terminal Unit
  • One, IDF
  • One, BME Equipment and Patch Panel

Control Cabling Installation

  • 5840m off, 4mm² x 4C Cu (BVX4ECV)
  • 360m off, 25mm² x 4C Cu (BVX4KCV)
  • 3940m off, 2.5mm² x 4C Cu (DVX4ECV)
  • 4190m off, 2.5mm² x 12C Cu (DVX12ECV)
  • 1670m off, 2.5mm² x 19C Cu (DVX19ECV)
  • 1270m off, Tel TPH10AV 10PR Cable

Stringing and termination of AAC Conductor (Supply and Install)

  • 800m off, “Bull”  1 x 800mm² Conductor
  • 850m off,  “Centipede” 1 x 400mm² Conductor
  • 430m off,  “Oak” Overhead Earth wire
  • 80m off, “Hornet” 1 x 160mm² AAC Conductor.

Fencing Supply and Install

  • 440m off, 2.4m High Palisade Fencing with anti-burrowing kerbing around perimeter.
  • One, 5m Motorised remote controlled sliding palisade gates
  • 123m off, 2m High Internal yard diamond mesh fence
  • One, 1.5m Diamond mesh Pedestrian gate
  • Two, 5m Diamond mesh internal gates.

Protection Installed for

  • 2 x132 kV Incoming feeders
  • 132 kV Double Busbars
  • 132 kV Bus Couplers
  • 132/11 kV Transformers
  • 11 kV Feeders
  • 11 kV Bus Protection
  • 11 kV Bus Section Controls

Auxiliary Supply

The auxiliary supply was obtained from the two 11 kV NECRT’s and a dual control yard AC distribution board with chop-over functionality was installed.

Supervisory and Telecoms (SCADA)

A SCADA Harris D20 RTU and IDF were installed. For the telecoms an optical fibre network was installed with a BME1630 multiplexer.