Poly Chlorinated Biphenyls (PCBs) in Power Transformers - An Indian Scenario

The Polychlorinated Biphenyls (PCBs) one of the Persistent Organic Pollutants (POPs) has been used as dielectric fluids in transformers and capacitors, as plasticizers and in hydraulic fluids. Though PCBs never produced in India, the usage of PCB oils began in 1960 in India and PCBs have been imported mainly for transformers and capacitors applications. The imported PCBs-containing electrical devices were mostly distributed in large enterprises and the rest were distributed in the electrical power sector. The transformers that were installed prior to 1985 was identified and analyzed using GC/ECD technique. Around 1617 transformers are found to containing PCBs and out of which, 1150 transformers are declared as pure PCBs filled Transformers. From the analysis carried out on the 467 transformers, 225 were containing >500 ppm of PCBs and the remaining 242 transformers containing < 500ppm of PCBs. The major sector that owns PCBs containing equipment is the power sector (71%) followed by the steel industries (18%). The total weight of the PCBs oils and PCB contaminated oil is around 10,000 tons, which is being updated.