keyhan2001
Electrical
I have a question about protection of high voltage (over 200kv) line.
Based on Siemens siprotec recommendation, high voltage line use two distance relay as sub1 and sub2 protection (main function). Also as common protection over voltage and DEF (directional earth fault) are used.
My question “DOC (directional over current) function is necessary for completion protection system or not?”
I know all famous brand distance relays including DEF and DOC. But I don’t know , if just DEF is enough why they were included DOC function.
On the other hand, we use two distance relay as main and backup. In this case, is there any need to additional function as DOC function for high voltage line?
Or is there any fault that may not clear by distance relays and need DOC function to clear it?
Another question is about 132kv line,
Also based on siprotec recommendation , they use under voltage as protection function,. But there is nothing about over voltage.
I think over voltage is also important for protection. And if this is not recommendation it means no fault leads to overvoltage.
Please give me some reference about that.
Based on Siemens siprotec recommendation, high voltage line use two distance relay as sub1 and sub2 protection (main function). Also as common protection over voltage and DEF (directional earth fault) are used.
My question “DOC (directional over current) function is necessary for completion protection system or not?”
I know all famous brand distance relays including DEF and DOC. But I don’t know , if just DEF is enough why they were included DOC function.
On the other hand, we use two distance relay as main and backup. In this case, is there any need to additional function as DOC function for high voltage line?
Or is there any fault that may not clear by distance relays and need DOC function to clear it?
Another question is about 132kv line,
Also based on siprotec recommendation , they use under voltage as protection function,. But there is nothing about over voltage.
I think over voltage is also important for protection. And if this is not recommendation it means no fault leads to overvoltage.
Please give me some reference about that.