Visakhapatnam: The Transmission Corporation of Andhra Pradesh (AP Transco) has decided to coat high-voltage ceramic insulators with silicone and replace the damaged insulators with silicone rubber composite insulators in the Visakha Switching Station, as well as the Kalpaka sub-station near Parawada.
These measures are intended to steer clear of accumulation of industrial pollutants and the subsequent technical glitches and power outages - technically known as ‘pollution flashover’. The Power Grid Corporation of India Limited had already initiated the same works, a few days ago.
After encountering a four-day consecutive power outage, the power utilities have come to a primary conclusion that the repeated technical glitches were precipitated only by the deposition of the soil dust, industrial emissions, fly ash and other pollutants on the ceramic insulators in the industrial area of Visakhapatnam. The settling down of pollutants on the insulators coupled with higher humidity-levels in the industrial zone has been making the transmission lines trip, interrupting the power supply.
The silicone coating and silicone rubber composite insulators are said to prevent electrical leakages, contaminant caused flashovers, etc. This also protects the insulators from the UV light, temperature, corrosive environments, etc.
The recent four-day power outage has hit about 30 lakh consumers of north coastal Andhra Pradesh within Andhra Pradesh Eastern Power Distribution Company Limited’s (APEPDCL) limits. After the AP Transco’s 400-KV sub-station’s failure on April 24, a technical snag at the 400-KV sub-station of the Power Grid near Visakhapatnam Steel Plant had thrown the power services out of gear for three days.
Subsequently, the APEPDCL had to impose a load relief of about 100-450 MW to various parts of East Godavari, Srikakulam, Vizianagaram and West Godavari districts for about four days in April.
Speaking to Deccan Chronicle, Superinten-ding Engineer, AP Transco, S.V.R. Krishna Mohan said pollutants are washed away with intermittent rains.
"But as there are no rains within the last 5-6 months, the tripping incidents have occurred. The silicone coating can prevent insulator contamination from industrial pollutants and emissions, soil dust, etc.
We have already changed about 80 ceramic insulators and placed silicone rubber composite insulators in the last 10 days. The materials for the silicone coating were imported from Canada and we would start those works too," he added.
