ISLAMABAD, (Muzaffargarh.City – 16th May, 2018 ) :The electricity transmission system which split into North and South due to tripping on Wednesday at 9:28 a.m. resulting in electricity supply failure to Punjab and Khyber Pakhtunkhwa areas was restored at 5:13 pm, after almost eight hours, with major power generation plants gradually increasing their input in the national grid.
According to the initial report the 500 kilovolt (kV transmission line Guddu 747-Raheem Yar Khan tripped at 9:28 a.m. and at the same time 500 kV Guddu-DG Khan transmission line also tripped, a Ministry of Power press release said.
As a result, the load increased on the 500 kV Guddu-Muzaffnrgarh transmission line from 733 MW/ 72 rtrIVAR to 1559 MW/ 717 MVAR as recorded at 500 kV Muzaffargarh end. This line also tripped at 09:28 a.m.
This tripping resulted in under frequency on system from 50.18 Hz to 48.755 Hz within 5 seconds. Resultantly, under frequency schemes came in action and frequency again improved from 48.755 Hz to 49.43 Hz at 9:28 a.m.
Meanwhile, some other power stations also tripped perhaps due to frequency fluctuation/ jerk and cascade tripping started in the northern part from Guddu to Peshawar.
The system went under partial failure from Guddu to Peshawar at 9:28 a.m.
when frequency decayed down to 45 Hz. The Southern part of country from Guddu onward however remained normal during the entire day which included Sindh and Balochistan areas, the statement said and added that as soon as the partial supply failure was reported the INTDC teams were immediately mobilized to check the high transmission lines.
Power Division also notified an enquiry committee headed by Additional Secretary Waseem Mukhatar to ascertain the causes of tripping. the process of restoration and suggestions for system to avoid such incident in the future.
The Additional Secretary will be assisted by three experts as member of the committee. It is however important to note that before the tripping the system was having surplus electricity as compared to the demand therefore the temporary load shedding was purely associated with system fault.
The Power Division has regretted the inconvenience caused to the electricity consumers in Khyber Pakhtunkhwa and Punjab due to the partial system failure, the statement added.