An explosion at the Medupi Power Station’s Unit 4 generator caused extensive damage to the generator, Eskom said on Monday.
“This explosion has resulted in extensive damage to the generator,” Eskom said.
“The incident occurred during the activity to displace hydrogen with carbon dioxide and air respectively, for the purposes of finding an external leak. Fortunately, no injuries were sustained by personnel who were on site during the unfortunate incidents.”
Eskom said that following a preliminary investigation, it appeared that while the activity was being performed, air was introduced into the generator when hydrogen was still present.
The power utility said the hydrogen was still present in sufficient quantities to create an explosive mixture, which ignited and resulted in the explosion on Sunday night.
“It also appears that there was a deviation from the procedure for carrying out this activity,” Eskom said.
“As such, Eskom has undertaken to place those employees who were responsible to manage and execute this work under precautionary suspension pending the conclusion of the major event investigation.”
Eskom said investigations were under way into the cause of the incident and to what extent it would affect the national electricity grid.
The power utility announced on Monday morning that Unit 4 at Medupi Power Station experienced an explosion at about 10.50pm on Sunday.
At the time, Eskom said the incident was suspected to have resulted in Unit 5 tripping.
“No injuries have been reported, and all employees and contractors have been accounted for. Emergency services attended to seven colleagues requiring treatment for shock,” the power supplier said at the time.
“Eskom will continue to provide support to the employees who might have been affected by the incident through its Employee Assistance Programme,” it said.
“Unit 4 was on a short-term outage (since August 6) when the incident occurred, and all work on the unit was suspended with immediate effect. This included the suspension of all permits to work on the plant until further notice.”
Eskom said the area was secured, and once it had been cleared by the fire chief and resident engineers, inspections and assessments would begin to determine the cause of the incident and the extent of the damage.
Eskom said preparations to return Medupi Unit 5 to service were in progress.