Green Liquid Leaked from CT Secondary Terminal Board of 132 kV GIS

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A thick, sticky green liquid was discovered leaking from two feeders of a 132 kV switchgear, raising concerns about its origin. Previous issues with cracks in the CT secondary terminal board led to replacements six to seven years ago, prompting speculation that similar damage may have occurred. Some participants suggested the liquid could be insulating oil mixed with preservatives or a reaction between vinyl insulation and copper, resulting in a dark green substance. The potential presence of polychlorinated biphenyls (PCBs) in the liquid raises toxicity concerns, emphasizing the need for testing before any contact. Caution is advised in handling the substance due to its hazardous nature.
Suri
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Hye everyone!

An unknown thick-and-sticky green liquid was found leaked from 2 out of 9 feeders, of our 132 kV Switchgear. The liquid was leaked through the cable gland that connected to the Secondary Terminal Board insulating cap of the Current Transformer, at the GIS.

I had done:
1) gas leak test - no gas leakage detected
2) hotspot test using thermography camera - no hotspot.

According to our chargeman, around 6-7 years ago, there is a case when they found out that inside the CT secondary terminal board, there was cracks. And all CT secondary board for all feeders was then replaced.

I just wondered if the same thing happened. Or the green liquid was just a kind of grease or softener for the cable.

Hopefully someone can help me. Thank you!
 
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It is probably insulating oil with some kind of preservative.
 
I have had cases where the vinyl or plasticizers reacted with the copper and created a dark green sticky substance. In one case it was clear insulation and I could see the fouling all along the cable.

BoB
 
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rbelli1 said:
I have had cases where the vinyl or plasticizers reacted with the copper and created a dark green sticky substance. In one case it was clear insulation and I could see the fouling all along the cable.
I have also experienced that corrosion in ordinary lamp cord with clear vinyl insulation. Annoying!
 
I would be careful. Polychlorinated biphenyls (PCBs) were widely used as insulating fluids in electrical equipment for many years. Wikipedia says, "One estimate (2006) suggested that 1 million tonnes of PCBs had been produced. 40% of this material was thought to remain in use. Another estimate put the total global production of PCBs on the order of 1.5 million tonnes. The United States was the single largest producer with over 600,000 tonnes produced between 1930 and 1977. The European region follows with nearly 450,000 tonnes through 1984."

These things are toxic. I would get it tested before you come in contact with it, if it's not too late.
 

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