Sakthia
Electrical
- Apr 21, 2003
- 1
I have a problem that we are facing currently at few of the 500KV substation. The problem we face as describe below.We have receive at least 10 trips in 2 months.
The station is a 1 1/2 breaker system,reactor and capacitor.
1. The current is not symmetrical and the angle was floating. So we beleive it was the star point that was the problem where it could be it was not properly thighten or intact as it should. So we thighten all the earthing and the angle and the magnitude of the current was stable.But the result at V phase was not satisfactory where Ia-256A,Ib-257A and Iv-126A. The neutral current was 24A (In). All the core that are connected to the protection shows the same value. So we beleive it could be the CT because the ratio should be 2000/1A and the Iv shows like it's connected to 3000/1A. When we check the internal connection and did the primary injection we found there aren't any problem with the CT and it is correctly connected to the appropriate ratio.Furthermore we found that the other station has the same value as above where the Iv is quite low. Could it be the system? But the other station we could find some strange phenomena like sometime B phase is efected as like Iv at the same line or another line.
I would appreciate if could get some tip and help on above description.
Thank you in advance everyone.
The station is a 1 1/2 breaker system,reactor and capacitor.
1. The current is not symmetrical and the angle was floating. So we beleive it was the star point that was the problem where it could be it was not properly thighten or intact as it should. So we thighten all the earthing and the angle and the magnitude of the current was stable.But the result at V phase was not satisfactory where Ia-256A,Ib-257A and Iv-126A. The neutral current was 24A (In). All the core that are connected to the protection shows the same value. So we beleive it could be the CT because the ratio should be 2000/1A and the Iv shows like it's connected to 3000/1A. When we check the internal connection and did the primary injection we found there aren't any problem with the CT and it is correctly connected to the appropriate ratio.Furthermore we found that the other station has the same value as above where the Iv is quite low. Could it be the system? But the other station we could find some strange phenomena like sometime B phase is efected as like Iv at the same line or another line.
I would appreciate if could get some tip and help on above description.
Thank you in advance everyone.