Energy minister Kgosiento Ramokgopa said the issue would be resolved by the end of the week. Photo: GCIS
Energy Minister Kgosientso Ramokgopa on Sunday said the current wave of load-shedding, the second since the start of February, was triggered by the loss of multiple units at Majuba power plant and will be over by the end of the week.
Eskom announced the implementation of Stage 3 on Saturday afternoon, but resorted to Stage 6 in the early hours of Sunday after further faults occurred at Camden and Medupi power plants.
“This is momentary,” Ramokgopa told a media briefing on Sunday morning.
“I am confident, by the end of the week we will be out of this. We will have gone through this wave … We have anticipated that these adverse headwinds are going to come.”
Eskom chief executive Dan Marokane said overload on a transformer at Majuba on Saturday afternoon caused a domino effect.
“Essentially what pushed us into the situation where we had to initiate load-shedding at very short notice at 5.30pm yesterday was the loss of multiple units at Majuba power station.
“This was occasioned initially by an overload on a transformer as a result of the start-up of a unit that was coming out of a long-term outage and that essentially started a domino effect of reticulation supply cutting to the rest of the units, and one by one those units gave in.”
He said engineers started addressing the cause of the failure overnight, and would work throughout the week to future-proof the plant against a similar fault.
Five units went down at Medupi, resulting in a loss of 3 000 megawatts of capacity and causing a unit at Medupi to trip because of the impact it had on the network.
“When we discovered the situation at Majuba yesterday, it also coincided with the trip at Medupi. We can now confirm that the trip had to do with the under-frequency in the network overall, that pushed that unit at Medupi into a position where they tripped.
“So they are all inter-related to some extent.”
At around 1.30am on Sunday, four units at Camden power plant went down and Eskom announced that load-shedding would be escalated to Stage 6.
Marokane said the failure of a hydraulic valve at Camden compromised the performance of cooling water pumps, prompting the loss of all units. He suggested that this failure was partly due to systemic weaknesses at Camden which Eskom was seeking to resolve.
“This is an area where we have been doing some work. We have done some interventions last November and we have plans to address that adequately going forward. ”
He said half of the ten units lost overnight had been returned to service by Sunday morning, including two at Majuba and one at Camden.
“We have recovered just in excess of 3 200 megawatts of capacity overnight.
“We expect two more Majuba units in the course of today, and in the next day or so we should have all the power station units that are available back in operation and we will proceed up to Tuesday to bring the rest of the Camden units back in operation.”
He said until this week’s incidents both “mainstay” plants had been performing well, with Majuba running at an average of 68 percent and Camden at 61 percent of capacity.
Ramokgopa apologised for this month’s renewed outages after more than 300 days of continuous supply and said he understood the public’s frustration that load-shedding was not yet a thing of the past.
He added that recurrences were part of the risk of a deliberately aggressive planned maintenance programme. It meant that 7 500 megawatts of capacity were offline when this weekend’s failures occurred.
“This is significantly higher than the same period last year, and we have accepted that there are inherent risks in this position that we have taken.”
But the minister said it would be more risky still to delay maintenance.
“We can be a bit conservative, but we are going to place a number of units at risk and when they fail I think the failure might be catastrophic and require us to take even significantly greater decisions for us to be able to protect the grid.
“The levels of planned maintenance, we will continue to maintain them at proportions that are in engineering terms acceptable but also help us to get to a situation where we are able to eliminate load-shedding in the shortest possible space of time.”
