ISLAMABAD: A six-member probe committee of the National Electric Power Regulatory Authority (Nepra) has held the National Transmission and Despatch Company (NTDC) responsible for the national power breakdown in October last year.

In a detailed inquiry report, the committee lamented NTDC for using 26-year-old and tampered conductors and inordinate delays in the completion of a dedicated transmission line for 2,200MW of newly energised nuclear power plants.

The inquiry committee also observed that a joint venture of another state-run National Engineering Services of Pakistan (Nespak) and Barqaab had vetted for too long the power evacuation from K2/K3 nuclear plants through an interim arrangement involving too many joints and a number of different clamps which could not sustain frequency fluctuation.

More ironically, the report noted that remedial recommendations following a previous breakdown in 2021 were not adhered to and even the system shortcomings identified at the time of Oct 13, 2022 breakdown for urgent rectification could not be removed seven months down the road till conclusion of the inquiry report on May 11. The inquiry, however, appreciated that system revival after the breakdown was reasonably quick.

The inquiry committee had checked the entire system from Karachi in the south to Ghazi Barotha in the north from all technical angles and found the initial cause of tripping to be overheating and consequently damage of T-clamps and conductor at the temporary diversion between location number 26A and 27 of 500kV K2/ K3-NKI circuit for the evacuation of power of K2/K3 plants. `Since the construction of dedicated transmission line for evacuation of power from K2/K3 could not be completed by NTDC, the interim arrangement was made which is continuing for an indefinite period as the dedicated T/Line is still incomplete`, the report said.

The report highlighted that the interim arrangement for K2/K3 power evacuation was vetted by Nespak and Barqaab joint venture being the consultant while the contractor for the project was Potential Engineers (Pvt) Ltd.

`The interim arrangement involves several joints, that too with different types of clamps, such as T-clamps and L-clamps, as per the availability at the time of execution,` said the report, adding that `conductor of transmission lines being used for interim arrangement is about 26 years old and installed in a heavily coastal polluted area, is deteriorated`.

At first, the fault developed on 500kV NKI K2/K3, circuit due to overheating and breakage of T-clamps of the jumper which resultantly tripped from both ends.

`This caused the shifting of load, about 2,700MW of China Power Hub Generation Company Ltd (CPHCL) and K2/K3, on remaining two circuits between K2/K3 and Jamshoro, as CPHGCL-Jamshoro circuit was already under scheduled outage`.

So far as failure of hardware within three years of commissioning is concerned, it`s because of improper interim arrangement, with non-standard or nonspecified hardware material and lack of periodic maintenance of transmission lines as per standard operating procedures.