An inquiry committee of the National Transmission and Dispatch Company (NTDC) has identified governance, ownership problems and poor chain of command for countrywide power breakdown early this year, but has absolved its own team of any responsibility.
In its report, the four-member inquiry committee also quoted letters written by some of its members for improvement of the electricity generation system and its safety protocols and equipment to prove that the NTDC had been highlighting the system’s weaknesses.
“No NTDC’s officer/official has been found negligent for discharge of his duties, as the event which initiated this widespread breakdown was not in NTDC’s system, rather it was in the 220kv Switchyard of Guddu Old Thermal Power Station under the control of CPGCL (Central Power Generation Company Limited),” said the inquiry report.
Moreover, it said the NTDC’s protection system detected the fault accurately and isolated the system in correct sequence and coordination. It was because of this fact that there was no physical damage to any equipment in the system despite a severe prolonged ‘three-phase bolted fault in generation station busbar’.
The NTDC’s inquiry team squarely blamed the CPGCL’s chain of command for the problem, particularly the officials working at the 747MW Guddu power station where the fault originally occurred. It said violation of standard operating procedures (SOPs), lack of technical expertise, lack of coordination and teamwork, lack of right men for the right job, lack of ownership and responsibility and lack of following the chain of command had been observed in the CPGCL.
At the same time, the inquiry report noted that approval for a study for provision of stability schemes, including determination of electrical centres, proposals of islanding schemes, etc., for NTDC’s existing network was already in process.
“Necessary steps need to be taken to ensure fast-track completion of the said study,” it said, adding “economically viable power plants need to be installed near the main load centre for improved system stability”.
The NTDC’s inquiry team also recommended that “automatic reactive power compensation equipment needs to be provided in the system and black start facility is essential and needs to be provided on all power plants near the load centre for quick restoration of power supply in case of such major breakdown”.
On top of that, the probe body also recommended that “frequency protection settings of all generating units are required to be reviewed and verified by concerned formations”.
The inquiry blamed the CPGCL’s team for concealing key facts and data recordings. For example, it held that “someone from Guddu 747 end had deleted the data stored in Sequential Event Recorder before the visit of the committee”.
At another point, the report observed that “wrong indications provided by CPGCL are either due to recording error or intentional cooking of facts just to justify their acts, but these are not technically tenable”.
The report said the switchyard equipment at 220kv Guddu end has been faulty since long. The breakdown event of January 9, 2021, started when the CPGCL staff tried to close 220kv circuit breaker — D12Q1 — without instructions from the National Power Control Centre (NPCC). Before closing the said breaker, the operation staff did not open the permanent earthing switch of 220kv isolator.
The said circuit-breaker controlled steam turbine and therefore the close operation of the said breaker always supervised the synchronism check relay. This relay only allows the closing of said break during live generator.
However, as during the operation of the breaker the steam turbine was in off condition, therefore the staff bypassed the electrical interlocking check.