A faulty transformer, and not load shedding

On November 6 residents had to make alternative plans when the lights went out suddenly. But it was not only eMalahleni that was left in the dark, also Thembisile and Dr JS Moroka municipalities were affected.

Very early on Friday, November 7 Eskom sent out a press release and said power system is severely constrained in the three municipalities, due to two faulty transformers at Vulcan Substation. Pressure build-up in transformer six was due to overloading. This resulted in the failure of a pressure-relief device and the tripping of the transformer.

Eskom’s technicians worked throughout the night on a contingency plan to manage the morning peak load and to expedite the completion of the maintenance on the transformers.
Eskom was continuously reviewing the situation and pulled in all specialists and resources to expedite the completion of the repairs on the transformers.

Transformer Six was re-commissioned at around 14:00 on November 8.
Transformer Five was switched off on November 4 for planned maintenance to be carried out.
Due to the severity of the fault on the transformer, as well as the added rainy weather conditions in the Vulcan area, the power system remained severely constrained over the weekend of November 7 to 9.

According to Eskom this won’t happen again.
“It is very rare that one transformer will fail when another is on planned maintenance. Contingency plans are in place should any other incident occur on any Eskom network,” they said.
“Eskom apologises to all affected customers. We would like to thank the top customers in the eMalahleni area for assisting by reducing their electricity usage,” their statement read.

There are a number of transformers of different sizes and different voltage ratios throughout eMalahleni networks. All transformers are currently in operation, except for Vulcan Transformer Five, which is still on planned maintenance.
From the local municipality’s side Mr Theo van Vuuren, the city’s administrator, said it is a fact that our electricity situation is under pressure and extremely sensitive to anything which may impact on it.
“We know that very well in our own situation in Emalahleni and the same is true on a national level, where Eskom is operating without the luxury of a safe spare capacity margin when anything goes wrong. There is always an impact on supply and the only variable is then the management capacity to minimise the disruption,” Van Vuuren said.
When Eskom needs to reduce load they will start by asking big industries to reduce loads, followed then by the bigger municipalities.

In that manner it is easier to manage.
“We are unfortunately one of the larger centres as we discovered last week. When Eskom reduces load, we start off with geysers, we can save up to 20% of our peak load in that way. If that is not sufficient we are forced to load shed,” he said.
Doornpoort serves the biggest area and if the interception is only for a short period, the most efficient way to switch off and reduce demand.

In prolonged outages, such as last week, the electrical team will rotate between substations. The situation is monitored constantly and between the head of the electrical department and Eskom, they are constantly checking and switching back as the situation may dictate.
“As our situation under normal conditions is also fragile, the electrical team is constantly monitoring and when a problem arises, address it in the shortest time possible,” Van Vuuren said.

They do ring-feed to minimise households being without electricity once the problem has been identified.
To complicate matters, more cable theft and illegal connections are reported.
Plans are executed to address these criminal activities.

In general the system is expected to be tight over the evening peaks for the next few days. Four of the six units at Majuba Power Station are in operation and currently generating 2 000MW. The dam levels at their peaking power stations, which use water to generate electricity, are at manageable levels and while the system remains vulnerable and tight, the probability of load shedding is low this week.

Eskom continues to appeal to consumers to reduce their electricity usage throughout the day, but especially from 18:00 to 22:00. Please switch off geysers, air conditioners, pool pumps and all non-essential appliances to prevent the need for rotational load shedding.

Should we need to go into load shedding, customers will be alerted as early as possible.
Eskom calls on all South Africans to pull together over the next few months and use electricity sparingly by ‘living lightly’ this summer. Less is more this summer and homeowners and businesses can do so with just four steps: first, switching off geysers and pool pumps; second, switching off non-essential lights; third, efficient use of air-conditioners by keeping the room temperature at 23C; and finally, responding to the alerts on TV each evening.

Eskom’s load shedding schedules are available for Eskom direct customers on their website. Customers can also contact Eskom’s Call Centre on 0860 037 566 for additional information.

Load shedding schedules will only be utilised for the duration of the constraint and Eskom will provide regular updates on the status of the power system.

For tips on how to trim 10% off your consumption, please click here.