question on wave for capture to determine a down stream fault
question on wave for capture to determine a down stream fault
(OP)
Been riddling over if a meter with wave form capture would provide enough information to sort out a down stream phase or ground fault.
The system voltage is 13.2kV with a main breaker fitted with an SEL protective relay with phase and ground fault. The 12 feeders are Westinghouse WLI fused load break switches. Each MVS has a Westinghouse DB4b-2fm 2 element watt meter mounted on the door. There are 2 CT's and 2 PT's in the MVS for the meter.
There was a ground fault on one of the feeder circuits that tripped the main breaker but we had no way to know which of the 12 feeders experienced the ground fault other than check each of the 12 feeders before being able to restore service.
Since we are planning to replace the old meters with new communicating meter would a meter with wave form capture allow us to get some idea of which feeder circuit experienced a phase or ground fault with only 2 CT's and 2 PT's?
I am thinking that by studying the voltage and current wave forms on each feeder after a main breaker trip should provide some evidence, maybe not conclusive, to narrow down the faulted feeder.
We are attempting to not have to take a shut down to add a third CT to each feeder and utilize the information we can get from a new meter.
Thanks in advance for humoring an old guy trying to figure out new technology.
Dan
A dream is just a dream. A goal is a dream with a plan and a deadline.
The system voltage is 13.2kV with a main breaker fitted with an SEL protective relay with phase and ground fault. The 12 feeders are Westinghouse WLI fused load break switches. Each MVS has a Westinghouse DB4b-2fm 2 element watt meter mounted on the door. There are 2 CT's and 2 PT's in the MVS for the meter.
There was a ground fault on one of the feeder circuits that tripped the main breaker but we had no way to know which of the 12 feeders experienced the ground fault other than check each of the 12 feeders before being able to restore service.
Since we are planning to replace the old meters with new communicating meter would a meter with wave form capture allow us to get some idea of which feeder circuit experienced a phase or ground fault with only 2 CT's and 2 PT's?
I am thinking that by studying the voltage and current wave forms on each feeder after a main breaker trip should provide some evidence, maybe not conclusive, to narrow down the faulted feeder.
We are attempting to not have to take a shut down to add a third CT to each feeder and utilize the information we can get from a new meter.
Thanks in advance for humoring an old guy trying to figure out new technology.
Dan
A dream is just a dream. A goal is a dream with a plan and a deadline.






RE: question on wave for capture to determine a down stream fault
Better yet, coordinate the fuses with the main breaker relay so that a fuse blows instead of tripping the main breaker. This means not having sensitive ground fault protection on the main.
Is the ground fault current greater than the maximum load current? If so, you might be able to use fault indicators on the feeders.
RE: question on wave for capture to determine a down stream fault
Regards
Marmite
RE: question on wave for capture to determine a down stream fault
If we took outages on each feeder I would add a bar CF on B phase and have 3 CT's then use a cummincating protective relay for metering and down stream fault detection and anunnciation.
I now realize that there would be no way for the meter to know when to triger the high speed wave form capture.
RE: question on wave for capture to determine a down stream fault
SEL 734/735
Novatech/Bitronics 70 series will fit into the existing meter hole, as it uses a detachable display.
The Schneider/PML ION7550/ION7650
Another option would be fault indicators. SEL makes an extensive line of these. https://www.selinc.com/FCI/Underground/
RE: question on wave for capture to determine a down stream fault
You'd need to add a CT and PT for each phase. The advantage of this style of metering is that there is no proprietary software, so your not stuck paying annual license fees. The output of the unit can be read with as a commtrade file and takes about all of half an hour to learn to use it.