PUTRAJAYA, Jan 16 — There was no element of negligence in the major power outage in several areas in the peninsula on July 27, 2022, caused by a tripping incident at the Yong Peng North main intake substation (PMU) in Johor.

Natural Resources, Environment and Climate Change Ministry (NRECC) said this was the finding of the Investigation Committee comprising independent technical experts formed by the Energy Commission (ST) to conduct a thorough investigation into the case.

The Yong Peng North PMU has been operating since 1987 and is an essential point in the grid system connecting the Southern Region with the Central and Northern Regions.

The electricity supply disruption affected several areas in the peninsula, including Petaling Jaya, Cheras, Bangi (Klang Valley); Bayan Lepas and Seberang Jaya (Penang); Panchor, Johor and Bandar Indera Mahkota, Pahang.

In a statement today, NRECC said the incident was caused by a fault in the disconnector equipment at the Yong Peng North PMU, which created a flashover that hit the adjacent line, resulting in the PMU being tripped.

“This incident has caused the grid system to split into two regions with different operating frequencies, namely 48.9Hz in the Central Region and 51Hz in the Southern Region,” it said.

In order to stabilise the grid frequency in the Central Region, the Under Frequency Load Shedding (UFLS) mechanism was activated to prevent the grid system from being completely paralysed with a load loss of 2,269MW involving 65 PMUs.

“The investigation found that the maintenance work at the Yong Peng North PMU was carried out according to the proper schedule, and no elements of negligence were identified as the cause of the incident,” he said.

According to NRECC, Tenaga Nasional Bhd (TNB) had taken swift action by replacing all disconnectors at the Yong Peng North PMU.

The ministry said the investigation was also to determine whether the incident complied with TNB’s Guaranteed Service Level (GSL), as it will be the basis for determining whether the customers involved are eligible for rebates.

“Based on GSL’s review, it was found that TNB completed the supply restoration process within two hours and 23 minutes -- which was still within the specified time.

“Therefore, there is no penalty in the form of rebates for consumers imposed on TNB,” the statement read. — Bernama