Energy25.01.2021

How a national blackout could happen

Eskom load-shedding headline new

In order for South Africa to avoid a national blackout, it is essential that the people working at Eskom’s National Control Centre and power station control rooms are competent and alert at a time when the grid is susceptible to outages.

This is according to power and mining expert Ted Blom, who recently spoke about Eskom’s situation on The Free Marketeers podcast hosted by the Free Market Foundation.

Simply put, a country-wide blackout can occur in the event that electricity demand exceeds supply, resulting in an imbalance and trip of the entire system.

Eskom’s implementation of load-shedding or load reduction is done to respond to unplanned events like breakdowns to protect the electricity power system from a total blackout.

When asked about the likelihood of a total blackout in the next five years, Blom pointed to the fact that South Africa’s power network required complex management.

“South Africa’s network is the most sophisticated and bigger than Europe’s – as far as I am aware,” Blom said. “You need to keep this system in balance 24/7,” he added.

Blom explained that there were two possible causes for a national blackout – human error and technological faults.

The human element

Key to preventing a national blackout are the people who work at Eskom’s National Control Centre in Simmerpan close to Germiston, Blom said.

This is the location from where Eskom monitors and manages its transmission network and determines when and where load-shedding and load reduction need to be implemented.

“Human error there is always scope for, people can fall asleep on the job,” he said.

“I have been inside that control room and believe you me watching a screen for 12 hours non-stop, one time or the other, you might make a mistake,” Blom said.

He claimed that one example where such a mistake had occurred within Eskom was when a worker at Duvha Power Station went to the bathroom at the wrong time.

“The guy who was supposed to watch the dial went to the bathroom and 30 seconds later, the thing blew. He didn’t release the valve he was supposed to,” Blom claimed.

The on-and-off problem

Blom stated that there was another possible issue that could arise due to power constantly being switched on and off for load-shedding.

He said transformers and electrical systems were not designed to be switched on and off constantly.

“Every time you are taking the load down and peaking the load a few hours later, you are looking for trouble,” Blom said.

According to Blom, this process results in the oil condensate that is intended to cool the transformers to settle down and form a mound.

“Eventually that mound will grow and the next time you switch it [the turbine] on it will just arc out and that grid will be gone,” Blom said.

“If the control room is not awake to keep that balance in the grid, that could result in a severe meltdown,” Blom said.

He went on to state that there were plenty of examples of this in countries including the USA, India, and Pakistan,

Blom said the question also needed to be asked over how long it would take to recover from a complete blackout.

This would depend entirely on the amount of damage the grid suffered due to the trip.

“If there is minimal damage, Eskom can probably bring the grid up within two weeks,” Blom said.

“If it’s severe damage, you are talking about 10 years, or never.”

“But I don’t want to scare people, let’s be positive and hope that the people at the control room at least are competent and very alert,” Blom said.

Below are images of Eskom’s National Control Centre in Simmerpan, Germiston.


Now read: The real reason Joburg load-shedding lasts 4 hours

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