Hello all,
I have a case where a long underground cable to be protected by step distance protection. This cable feeds a unit substation with a power transformer which effectively falls in zone-2 of the cable to be protected by distance protection. I would like to understand if zone-2 and...
Hello,
I have a requirement from my client to have all equipment in a 69KV outdoor Switch-yard be UL listed. However, I coudln't find any outdoor products in the market with an UL or Recognized UL mark. Some of the vendors I contacted, said they cant supply. I'm bit confused if really UL...
Hello,
I have case to troubleshoot. We have two identical motors following attached schematic. The controller has an indication of 'phase reversal' probably comparing with what is defined in factory as correct. This indication makes the motor / pump unavailable for a remote start.
We are...
Hello,
Could you please share your experiences on primary injection tests for circuit breaker of high current ratings (say 1600 to 5000 Amps) with integral trip units. I can't see many commercially available test equipment capable of supplying the level of currents. Needless to say, true...
Hello,
We have case from construction site, where the cable is glanded incorrectly on the star point terminal box instead of main terminal box on the other side of a medium voltage star connected motor. It is difficult now to get the extra length of the cable required to re-route, we started to...
Hello,
I've come across a requirement to use 400V generator to temporarily (say one month) power up an existing plant's electrical network till the main power (gas turbines) kick-in. The only option is to connect the LV generator is at an 11KV incomer reserved for future use. So step-up...
Incase of a cable feeding power from one switch-gear to another one, I understand that the cable better shall be sized as per the least of outgoing breaker of later and incoming breaker of the second one. But sizing as per the connected load on the downstream swgr is not a good practice as we...
Hello,
Can you share your thoughts on calculation of capacitive current calculation in a industrial electrical system.
I see a recommendation in one of our reference documents says like this
"capacitive contribution to the earth fault on the part of the 11 kV cables shall be less than the...
I have a 400V switchboard with two incomers : one from emergency diesel generator (400V) and second from main power (gas turbine power @11kV stepped down to 400V thru couple of other switchgear in the overall system).
I would like to have load transfer from emg incomer to the main power incomer...
Hello,
I am using a softstarter for a 6.6kV, 1650kW motor (FLA=172A,LRA=5x172A) by limiting the current to 250% for 14 seconds where as the motor max. stalling time is 20sec at 100% term. voltage.
Although the current is limited to 250% for the 14secs, it reaches a peak of ~340% soon after the...
I have got a doubt. This might be silly a question to some people. But this is irritating me from long time
-Why does two words "EARTH" and "GROUND" are used? Is there any technical difference between them?
Based on my knowledge, I felt that EARTH/EARTHING we use in AC. and Grounding is some...
