LAHORE: The National Transmission and Despatch Company (NTDC) has started washing its 500kV and 220kV transmission lines across the country to ensure smooth power evacuation, transmission and despatch to the 132kV distribution system and onward supply to consumers.
The activity will also avert any major power breakdown, as the deposition of pollutants of smog emerging from fuel emissions, industrial smoke, foggy weather etc cause reduction of the lines’ insulation level, disturbing smooth power flow and leading to breakdowns especially in winter.
According to a senior NTDC official, lines, insulators, towers, discs and conductors will be washed, nuts and bolts tightened and nests removed.
From Nov 23 to 26, teams worked on lines passing in Multan, Muzaffargarh, Rajanpur, Guddu, Jaranwala Road, Sargodha, Nishatabad, Jhang, Rawat, Nokhar, New Lahore, ISPR (Sangjani), Mansehra, Mandi Bahauddin, Sheikhupura and Islamabad, according to NTDC Managing Director Zafar Iqbal. He told Dawn that decreasing insulation level of the 500kV double circuit Port Qasim transmission line caused occasional tripping and interruption of power transmission and supply to distribution system. They were mainly due to deposition of pollutants emerging from the sea salt impact and fuel emission from the adjacent K-Electric’s oil-fired power plant.
“The initial stretch (8-9km) of the line, which is situated near the sea and the plant, is very critical, as it needs an immediate rehabilitation to avoid any untoward event in near future,” he explained. He said the 55km-long Port Qasim transmission line originated from its plant and ends at Hub, connecting Jamshoro-Guddu transmission lines.
Insulators, he said, played an important role in transmission lines as whenever there was pollution, the insulation level decreased. It happens when some stick material falls on the insulators as a result of a mixture of emissions and air moisture.
“To deal with this issue at this line, the NTDC is working on a pilot project to replace the normal insulators with RTV (room temperature vulcanising) coated insulators on first 10-km stretch of towers in first phase. The coating actually prevents material from sticking to insulator surface. It is a preferred solution worldwide and reduces the frequency of washing,” the official explained.
“From Dec 26, we will start executing this pilot project, as the shutdown of the Port Qasim plant has been approved in this regard,” he added.
Published in Dawn, November 28th, 2018