ISLAMABAD/KARACHI/LAHORE: The country’s power system faced on Sunday morning another major breakdown in 10 days — this time affecting almost the entire province of Sindh, including Karachi and Hyderabad, and parts of Balochistan.

According to the National Transmission and Dispatch Company (NTDC) and K-Electric (KE), the fault originated from the southern 500kV Dadu-Guddu transmission line due to heavy fog. But they also blamed each other for the over 12-hour breakdown.

The NTDC said it had re-energised Jamshoro-Hyderabad and parts of KE’s main supply by 12 noon and was able to completely restore supply to KE by 2pm as the Karachi-based power utility struggled to revive its own plants and synchronise with feeders by 4pm.

There were conflicting reports about the affected areas. While the NTDC claimed that power supply to Balochistan remained unaffected and Guddu power station and its supply areas remained functioning, a spokesperson for the K-Electric said Balochistan was also affected.

On Dec 12, a fault at the Guddu power station had plunged Punjab and Khyber Pakhtunkhwa and some parts of Sindh and Balochistan into darkness. As officials exchanged blames, an internal investigation led to suspension of three senior officials of the Guddu Thermal Power Company.

A spokesperson for the NTDC said two parallel lines from the 500kV Jamshoro-Guddu-Dadu line tripped early in the morning and the Jamshoro power plant and KE’s system faced a major outage, followed by a domino effect on almost all feeders.

The NTDC said three distribution companies in Sindh – K-Electric, Hyderabad Electric Supply Company and Sukkur Electric Power Company – were completely out of the system. It said engineers’ teams tried to revive the southern line but faced problems because of heavy fog, adding that supply to the Jamshoro plant and KE was restored by the noon.

The spokesman said a report on the outage and its delayed revival had been submitted to the National Electric Power Regulatory Authority (Nepra).

The K-Electric claimed that the breakdown of transmission from the NTDC was the main cause of outages in most areas of Sindh, including Karachi, and in Balochistan. The tripping of NTDC’s 500kV transmission line from Guddu/Dadu caused a sudden overload to the network of K-Electric and Hubco, leading to outages.

“The sudden disruption of supply from the NTDC technically tripped the entire system to which the power utility/generation companies of Karachi and Sindh are connected which includes KE as a major player. The tripping had a domino effect leading to a series of outages in grids supplying power to Karachi.

“In such a scenario, our first priority is to restore our connection from the NTDC. However, that was not possible due to heavy fog in the first instance and, therefore, KE immediately went into stand alone “Island Mode” – isolating the NTDC on a temporary and limited basis – to restore power to the city,” KE’s spokesperson said in Karachi.

“Our engineers worked to power up key installations, e.g. priority health services (hospitals), PAF base and the Jinnah International Airport, along with some other key defence/security establishments, and were able to do so progressively within the first two hours of the breakdown.”

He said the NTDC’s power transmission to Karachi was back online around 2pm. “KE’s engineers then worked to synchronise KE’s system with the NTDC with zero disruption, which was not a small technical feat, achieving full restoration of power to KE’s entire commercial footprint, which includes parts of Sindh and Balochistan.”

The spokesperson also said that the inclement weather in winter in the form of dense fog in tandem with low ambient temperatures adversely affected the NTDC system which was the major cause of such nationwide power breakdowns that consumers had faced in the recent past.  

He said the KE apologised to its consumers for the inconvenience and promised to make every effort to serve them with professional zeal and commitment.

In Lahore, NTDC Managing Director Tahir Mehmood told Dawn that the tripping in 500kV Guddu-Dadu transmission line/grid station caused suspension of supply of 650MW to Sindh.

He said repair work took time because of weather and supply was restored after cleaning the transmission line and replacing the damaged parts and switching to other transmission lines, grid stations and feeders.

He said the KE system was also affected which caused delay in restoring electricity to Karachi.

Mr Mehmood clarified that Balochistan had not been affected by the tripping of the Guddu-Dadu transmission line because it received electricity through the 500kV Guddu-Khuzdar line. “There may be some internal problems due to which some parts of Balochistan also faced power shutdown,” he said.

Published in Dawn December 22th , 2014