LAHORE: A major power breakdown caused due to the tripping of 500 kilo volt (kV) and 220kV transmission lines hit major cities of Punjab on Monday.
The breakdown originated from Islamabad at about 11am after the Rawat 500kV/220kV double circuit transmission lines tripped owing to overloading, leading to a shutdown of operations of the 500kV grid station resulting in power supply suspension to the federal capital, Rawalpindi and adjoining districts, including Jhelum.
Rawat’s cascading effect travelled to the major 500kV/220kV double circuit Ghakhar transmission lines and grid station that shut all 60 132kV grid stations in Gujranwala, Sialkot, Gujrat, Kamoki, Sadhoki, Hafizabad, Mandi Bahauddin and Narowal.
It further affected the 500kV Sheikhupra line and grid station and 220kV Kala Shah Kaku line and grid station leaving dozens of 132kV stations of Lahore Electric Supply Company (Lesco) without power and a large number of consumers in Sheikhpura, Muridke, Shahdara and many urban and rural areas of Lahore without electricity.
“It is clearly negligence on the part of National Transmission and Despatch Company (NTDC), as it was scheduled to remove a major system constraint in the 500kV Rawat grid station before the start of summer. The company was to add a 750 mega volt ampere (MVA) transformer to the grid station to absorb the load and transfer it to the 132kV distribution system for supplying uninterrupted electricity to consumers. But it failed to do so,” an official of the power division explained to Dawn.
According to an official of the Gujranwala Electric Power Company (Gepco), the tripping originating from Rawat station tripped the entire distribution system. “It hit the NTDC’s 500kV/200kV double circuit Ghakhar grid station, leading to a shutdown of our all 132kV distribution grids at least for 45 minutes. We resorted to loadshedding so we could energise 60 grids,” Rana Jahangir, a Gepco spokesman, told Dawn.
On the other hand, many 132kV grid stations and transmission lines of Lesco also tripped due to the breakdown. “Due to tripping of the 220kV Kala Shah Kaku, Ravi, Shalamar and Ghazi grid stations, many of Lesco’s 132kV grids stopped working. However, we managed to energise 60 per cent of all the grids by 2:30pm and all of them by 5:30pm,” claimed a Lesco spokesman.
However, according to sources, Lesco’s system could not be restored fully till 7:30pm. Power supply in Gujranwala, too, could not be restored fully till 7pm.
When contacted, a senior NTDC official admitted that the 500kV Rawat grid could not be upgraded due to some issues. “A 750MVA transformer was required to be added to the Rawat grid but it was delayed. The transformer has now reached Karachi by ship from South Korea and we will receive it in the next few days,” the official explained. “However, Rawat’s 220kV portion has been upgraded.”
When asked how the NTDC would deal with the rest of Ramazan and summer since Rawat grid’s upgrading might take a couple of months, he said experts were working on it through load sharing or other methods.
Published in Dawn, May 22nd, 2018