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August 17 power blackout: Initial report slams CEB for ignoring recommendations by experts in the past
An independent committee that investigated the August 17 electricity blackout has slammed the Ceylon Electricity Board (CEB), saying its failure to avoid the mishap points to “significant lapses” in implementing critical recommendations made by experts in the past.
The CEB must introduce “standard, compliant, systematic, foolproof, safe procedures and maintenance protocols” during operation and maintenance, the 9-member committee’s interim report said. The utility also has no operations and maintenance-related risk management mechanism. These are only some of the shortcomings highlighted.
The committee produced its report in three days and was only provided with initial data. Much more is required before its final determination, due in about two weeks, is issued. Another set of inputs was expected even yesterday. The members also did site visits for observation.
While the CEB has laid much of the blame on an Electrical Superintendent (ES) who caused an earth fault at the Kerawalapitiya substation which triggered a system collapse, the committee has also highlighted the absence of basic best practices that contributed towards the incident.
For instance, the ES took up a routine maintenance job at the substation which was nevertheless high risk. Permission had been obtained and the maintenance area released. But he was by himself and was not supervised by any of his superiors–a usual practice. The CEB has made no risk assessment. And there was “no robust maintenance protocol in placed”.
The committee has recommended that the utility identifies maintenance practices of high risk areas and incorporate best practice protocols in maintenance in such places “rather than having a general maintenance philosophy”. There hadn’t even been a checklist.
The substation is connected countrywide through the power supply network which has automatic mechanisms to protect, identify and isolate a fault. The question then is why the fault propagated to the rest of the system, and whether protections are fast enough.
The cascade started when the coal power units at Norochcholai tripped. One unit switched off while two were in “house load”–functioning but off the network–for at least one-and-half to two hours. This meant that the CEB could still have resurrected supply by connecting them to the grid.
Electricity supply in the system dropped to about half within milliseconds. With demand being higher than supply, there was a cascade and a countrywide blackout. Still, experts conclude, everything should have come online faster. The General Manager himself has predicted restoration to take place within two hours.
But it took, at a minimum, six-and-a-half hours and the reasons the Committee provides for this are technical (called over-frequency).
One of the basic premises of the experts is that, whilst none of the previous power failures were “exactly similar” in nature, if recommendations by earlier Committee s had been adopted, some problems could have been mitigated.
“When there are no standard procedures following typical maintenance protocols, you have to expect this kind of mistake (by the ES),” one authoritative official said. “Don’t camouflage the overall incident based on the actions of one person. And there is still no answer for why it took more than six hours and seven attempts to restore power.”
The committee has not only recommended protocols for operation and maintenance but for implementation to be “continuously monitored and supervised by adequately qualified, professionally trained, knowledgeable, experience and skilled personnel”.
It also calls for a risk management mechanism to determine “proper mix of preventive measures, mitigation levels, shift or retention of risk…” It urges a review of the existing protection strategy for frequency instability, among other recommendations.
All’s not well yet
The CEB continues to face difficulties getting all three units of the Lakvijaya coal power plant online. The problematic Unit 1, which has broken down repeatedly since its commissioning in 2011, has not functioned since the August 17 countrywide blackout although CEB officials said yesterday that it was expected to rejoin the grid yesterday or shortly. A problem with its condenser tubes was being tackled for days.
While Unit 2 is functioning at its full 300mw capacity, Unit 3 is only offering 210mw to the grid. This is because it has separate issues with its cooling water pump.