Pretoria getting load rotation after pylons collapse

3 years ago 1

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The City of Tshwane (CoT) will start implementing load rotation/reduction to provide areas that have been left without electricity for multiple days with some intermittent power.

The collapse of seven pylons holding 132kV high-voltage power lines occurred during a windy storm at roughly 21:00 on Sunday, 9 April 2023.

The incident plunged large parts of Pretoria East, Pretoria North and a portion of Centurion into darkness.

It also forced the closure of the N4 highway until late on Monday afternoon, as a section of the cables had fallen across the road and caused several accidents.

Many areas have since had their power restored due to CoT diverting electricity from alternative substations.

However, over 40 suburbs remained without power as it was not technically possible to divert their electricity feeds to other substations without causing overloads.

To address this, the city’s energy and electricity technical team has now taken the “extraordinary” step to feed the Waltloo and Mamelodi Substations with electricity from the Njala infeed substation.

“Ordinarily, Waltloo and Mamelodi substations are fed by the Pumulani substation, which has also been affected by the power outage which occurred on Sunday night in the wake of suspected vandalism of a pylon along the N4 east freeway,” the city explained.

As a result, it will have to implement load rotation (reduction) in areas that have power to re-channel electricity to areas that have experienced a prolonged outage.

CoT said the energy and electricity technical team changed settings and performed protection grading at the Njala infeed substation on Tuesday evening and completed the work on Wednesday morning.

“The switching team was dispatched to the Waltloo and Mamelodi Substations this morning to start energising transformers to soak, after which they added the load gradually, while constantly monitoring the load.”

“Gradual switching will commence shortly.”

CoT said that this was an interim measure that would likely overload the system, resulting in possible trips.

“To obviate possible trips due to overload, the city will implement a 4-hourly load reduction in some areas of Watloo, Mamelodi (1,2,3), Pumulani and Koedoespoort supply area,” said CoT.

In addition, the load rotation will impact parts of Tshwane region 2, 3, 5 and 6, which include the following areas:

Region 2 — Hanmmanskraal, Montana, Sinoville, Temba, Wonderboom
Region 3 — Brooklyn, Hatfield, Pretoria CBD, Pretoria West
Region 5 — Cullinan, Rayton, Roodeplaat
Region 6 — Eersterust, Mamelodi, Pretoria East, Shere

The city acknowledged the “pain of load reduction” on top of load-shedding being implemented by Eskom but wanted to ensure the even and balanced provision of power to all residents.

The city said it would communicate the specific schedule for each area in due course.

Eskom is supplying and helping Tshwane with rebuilding the power pylons and told Afrikaans newspaper Beeld the work could take up to five days.

The utility has previously said the estimated cost of rebuilding a power pylon was between R3-4 million, which would put the total cost for seven pylons between R21-R28 million.