Eskom’s System Operator has reiterated assurances that the power utility has enough “defensive barriers” to prevent a national blackout in South Africa in spite of the ongoing electricity deficit.
This comes after Eskom yesterday ramped up load shedding to Stage 4 until Saturday evening due to the breakdowns of eight generating units on Tuesday evening.
Breakdowns have increased to 19 127MW of generating capacity while the generating capacity out of service for planned maintenance is 2 313MW.
Eskom’s General Manager System Operator Isabel Fick yesterday said that Eskom had in place at least six defensive barriers to avert a grid collapse, including a reserve margin of 2 200MW available at any time.
Fick said though South Africa did have a capacity generation problem, this has not caused system blackouts in the past and will not start now.
“The probability of a national blackout is extremely low. A number of other areas across the world did have national blackouts. Nowhere will you see they were because of a lack of capacity that caused a national blackout,” Fick said.
“In all those cases it was a cascading event starting in the transmission space. We have never had a national blackout in South Africa.
Fick said the country had only had regional blackouts before and load shedding had no role in both.
“We have had two regional ones before. One was an event where we had a transfer limit issue to the Western Cape and the other was a snow event in KwaZulu-Natal.
“In those cases we had to deal with a regional blackout and in the case of the Western Cape, we started load shedding in 2006 which was the basis of the current load shedding regime that we are using in South Africa.”
Fick was speaking during a webinar hosted by the Government Communication and Information System (GCIS) on the myths and facts about electricity grid stability.
She also said even though Minister of Electricity Dr Kgosientsho Ramokgopa had warned that bottlenecks in the transmission grid pose a threat to any remote possibility of a grid collapse, this did not give her sleepless nights.
“It is not a question that the transmission grid is in any bad shape. We do regular maintenance. Our maintenance is around 98%. So we're doing very well on on that front and functioning well,” she said.
“We also monitor our equipment when they operate. So, in cases where equipment operates more often like with load shedding, we do maintenance at more frequent intervals so that we protect the national grid. So no, from a transmission perspective, I do not have sleepless nights.”
The Council for Scientific and Industrial Research (CSIR) principal researcher Sipho Mdhluli emphasised that load shedding was implemented to ensure that frequency remained within a frequency dead-band.
“The South African grid is highly integrated and has a lot of automated processes in place over and above manual load shedding. For example, the system has under frequency load shedding system will automatically shed load to prevent grid collapse,” Mdhluli said.
“Total grid collapse is not highly probate, but we cannot totally exclude it as completely impossible.”
The South African Institute of Electrical Engineers fellow, Professor Jan de Kock concurred with Fick about the low possibility of a grid collapse, saying Eskom has developed defensive strategies and contingency planning around it.
“It’s fair to say that it’s highly unlikely that we’ll have a total grid collapse in South Africa. We can’t say it will never happen but it’s really unlikely,” De Kock said.
“Our grid at this stage is well managed and we have excellent people investigating causes of small disturbances, multiple unit trips and in the process we’re actually improving grid performance nearly on a daily basis.”
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