CLP report says two power incidents in Tsing Yi 'isolated cases'

CLP Power Hong Kong said both power incidents that occurred in Tsing Yi earlier this month were "isolated cases" occurring at two different power systems with varying voltage levels, as the power giant submitted the investigation report to the government.

CLP announced last night that it had passed the report regarding the voltage dip incident at Nga Ying Chau Street Substation - which occurred on January 1 - to the Electrical and Mechanical Services Department (EMSD).

It has already submitted the investigation report concerning the power incident on January 7 at On Mei House of Cheung On Estate last week.

The power giant stated that the two cases that occurred in two separate power systems with different voltage levels were confirmed to be independent incidents after investigation and examination by third-party electrical engineering experts.

According to the report on the Nga Ying Chau Street incident, the automatic protection system was triggered to isolate the malfunctioning section since a 132,000-volt cable sealing end inside the substation had failed. CLP said it results in temporary voltage drops and no interruption to the power supply.

It was found that the insulation material inside the faulty cable sealing end had degraded, leading to a short circuit.

As for the On Mei House case, an 11,000-volt cable connector at one of the customer substations broke down, affecting the electricity supply of 388 customers in the building.

It was found that moisture seeped into the inner part of the cable joint because the waterproofing capability had deteriorated. The cable joint has been replaced on the same day.

CLP Power said it is also inspecting the same type of cable sealing ends and cable joints in other districts after checking the power supply equipment in Tsing Yi.

It continued that the company will further review the maintenance arrangements for the electricity supply system in conjunction with an independent industry consultant while carrying out repairs with reference to international standards and industry best practices.

The company will also learn from the incidents and adopt practicable solutions to minimize the chance of electrical accidents.

Given the recent power incidents, EMSD will step up inspections of the facilities and operations of the power companies to ensure their technical and electrical safety performance.