vinod
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- Saudi Arabia
I found the CT terminals are melted during 7.7MVA transformer secondary CT (2000/5)testing, What could be the cause for this damage. Kindly give some possible reasons
CT terminals melted
- Thread starter vinod
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Would like to see more of the surrounding area, but it looks like some sort of major arc fault happened in the vicinty of that C.T.
Any other damage to the transformer?
Oh, possibly someone open-circuited the other end of those CT connections, I understand that that can create extremely high voltages.....
Any other damage to the transformer?
Oh, possibly someone open-circuited the other end of those CT connections, I understand that that can create extremely high voltages.....
Very common, look for loose terminal wiring connections. CT's are current ratio devices. A common ratio is like 600:1 meaning for every 600-amps input, the CT produces 1-amp output. Well current and voltage are inversely proportional. If the current ratio is 600:1, then the voltage ratio is 1:600. So if you open the CT, the voltage will go to 600 times whatever voltage is being monitored.
There has been many utility substation Metermen and Relay Technicians severely burned and/or killed by lifting CT leads on energized in metering circuits. So always make double darn sure the shorting screws on the terminal block are tight and fully engaged before ever thinking about working on CT’s. If not you are a dead man flaming. Even better, shut off the power and use shorting screws if possible.
There has been many utility substation Metermen and Relay Technicians severely burned and/or killed by lifting CT leads on energized in metering circuits. So always make double darn sure the shorting screws on the terminal block are tight and fully engaged before ever thinking about working on CT’s. If not you are a dead man flaming. Even better, shut off the power and use shorting screws if possible.
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