Lawley Electrification

In 2014, City Power awarded a 3 year contract to F & J Electrical for the electrification of Lawley; an informal settlement, south of Johannesburg, which falls within the City of Johannesburg’s (City Power) supply area at grid references S 26°20’10.11″, E 27°48’28.85″.

This is a pilot project in line with the Constitutional mandate and the commitment made by Councillor Parks Tau, the mayor of the City of Johannesburg, to improve the service delivery of energy to informal settlements where formalisation may not take place in the foreseeable future.

After intensive research for solutions that would include making use of the existing grid as well as including other innovative options that would be practical for implementation purposes and would also meet the expectations of the residents, City Power gave F&J Electrical the mandate to provide the following services.

1. 20A Electrical grid connection (designed for 2.5kVA ADMD per stand)
2. Gas installation (LPG) for cooking purposes.
3. Solar PV installation for lighting purposes. (Hybrid/Grid tie option)

SCOPE OF WORK

Energy supply from the grid
Lawley will be fed from an existing Eskom supply point near this informal settlement. However, Eskom has indicated that only 1MVA is available on the Eskom network for the Lawley informal settlement.
According to City Power’s Network Services Planning Department, the existing Eskom 11kV Overhead line will be extended and an 11kV CT/VT Metering unit will be provided to give City Power a bulk 11kV connection. A new 3.68km 11kV overhead line will be constructed to reticulate the electrification project at the Lawley informal settlement.

The technical requirements set by City Power for the agreed upon options are as follows:

The Grid

• Internal reticulation design documents
• Volt drop studies and protection schemes
• Civil infrastructure
• Bill of materials
• Project program (start and finish date)
• MV load flow and forecast
• Project costing

Gas:

• The establishment of a gas depot within the area.

Gas Stove:

• A portable 2 plate gas stove on a cupboard with basin/bucket combination per dwelling,
• All gas stoves must have an automatic gas cut-off function
• 1 x freestanding 6kg gas cylinder in a lockable cage/cupboard per dwelling.

PV Requirements:

• Structure for PV frames (PV must carry a minimum of 3kW and the structure must be able to withstand the impact of PV and its associated components)
• Anti-theft mechanism (security features)
• Ability to supplement the grid (grid-tie)
• Protective structure housing batteries, inverter, charge controller, statistical metering and islanding equipment

Overall Capacity Required:
Lawley: 2100 dwellings = 4.2MVA
Proposed Design

• The construction of an LV network in a street-front layout on 7.5m pre-stressed concrete poles, with 7m poles between the dwellings.
• The 7m poles will carry/lift the service connections to the dwellings at the back of the stand.
• The installation of 6 or 9-way overhead protective structures on the 7.5m concrete poles.
• The installation of a ready board and prepayment meter (split type) in each dwelling.

3kW PV System:

• 12 x 250W solar panel
• 1 x 3KW pure sine wave hybrid inverter
• 1 x Pole mounting structure
• Accessories (cables, circuit breaker, Isolator, fuses, etc.)
• 8 x 12V/100AH battery (9,6kWh)
• 500W per stand, after diversity

Grid Connection:

• The installation of a 20A grid connection per stand.
• The installation of an all overhead network.
• The installation of a Bulk supply from Nirvana to an 11kV switching station on the boundary of the settlement for the Thembelihle development.
• Application for a larger network connection from Eskom for Lawley Station.

The following aerial photographs indicate the location of Lawley and the medium voltage design layout.