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

In summary, there was a thick-and-sticky green liquid leaked from 2 out of 9 feeders in the 132 kV Switchgear. The liquid was found to have leaked through the cable gland and there were concerns whether it was insulating oil or a type of grease. Testing was done, but no gas leakage or hotspots were detected. It was discovered that 6-7 years ago, there was a similar case where cracks were found in the CT secondary terminal board, resulting in its replacement. There is a possibility that the green liquid is a result of a reaction between vinyl or plasticizers and copper, as seen in previous experiences. However, it is important to be cautious as it could also be a toxic substance like
  • #1
Suri
1
0
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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  • #2
It is probably insulating oil with some kind of preservative.
 
  • #3
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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  • #4
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!
 
  • #5
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.
 

1. What is the cause of the "Green Liquid" leak from the CT Secondary Terminal Board of a 132 kV GIS?

The most likely cause of the green liquid leak is a failure of the insulating material used in the CT Secondary Terminal Board. This could be due to a manufacturing defect, damage during transportation or installation, or natural degradation over time.

2. Is the green liquid harmful to humans or the environment?

The green liquid is most likely a type of insulating oil or gas, which can be harmful if ingested or inhaled in large quantities. It is important to follow proper safety protocols and clean up any spills promptly. The impact on the environment will depend on the specific type of liquid and the amount leaked.

3. How can the leak be repaired?

The leak will need to be assessed by a qualified technician to determine the best course of action. In some cases, the affected part may need to be replaced. If the leak is small, it may be possible to seal it with a specialized adhesive or sealant. It is important to follow proper safety procedures and consult with the manufacturer before attempting any repairs.

4. Can the leak cause damage to the GIS equipment?

If left untreated, the leak can potentially cause damage to the GIS equipment. The insulating liquid or gas is essential for preventing electrical discharges and maintaining the proper functioning of the equipment. If the leak is not addressed, it can lead to malfunctions or even failure of the equipment.

5. How can similar leaks be prevented in the future?

To prevent similar leaks, it is important to regularly inspect and maintain the GIS equipment, including the CT Secondary Terminal Board. This can help identify any potential issues before they become major problems. It is also important to follow proper installation procedures and use high-quality components to reduce the risk of failures and leaks.

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