Metering testing
Metering testing
(OP)
Anybody here has the experince on the installation and testing of Substation metering Cabinet?
The metering cabinet is located on the secondary of 138KV/4160V Transformer. Site superviser told me he has seen so many mess-ups on the metering cabinet. To me, it is a just metering equipment. As long as the CTs and PTs are wired correctly, all the cables and grounding are installed properly, there should not be ant issues. Any other things I should pay attention? Any inputs would be much appreciated.
The metering cabinet is located on the secondary of 138KV/4160V Transformer. Site superviser told me he has seen so many mess-ups on the metering cabinet. To me, it is a just metering equipment. As long as the CTs and PTs are wired correctly, all the cables and grounding are installed properly, there should not be ant issues. Any other things I should pay attention? Any inputs would be much appreciated.






RE: Metering testing
Key is to meet the utility company's specs for cold or hot sequence, CT/PT type, ratio and class etc., size( dimensions) of the cabinet and any other special requirements or preference for a mfr. etc. You cannot just install whatever a mfr. will provide.
Rafiq Bulsara
http://www.srengineersct.com
RE: Metering testing
Rafiq Bulsara
http://www.srengineersct.com
RE: Metering testing
Do NOT assume that the design people "knew" what they were doing. I (and many others) have found the design drawings to be horribly wrong. Do spend a bit of time in a "reality check", verifying polarities, ratios, connections, etc. against the desired characteristics to be measured.
Upon finding the drawings correct, develope a commissioning test plan that will verify correct installation. Secondary injection tests from the instrument transformers themselves are needed before energizing. If programmable devices are used, verify the program.
Upon initial energization check the indications on the metering, including during such load tests as may be done, against other indicators such as advanced protective relay indications, etc.
If you're talking about checking metering that has been installed and in service, do you have indication that it has EVER worked correctly? If it has, and now isn't, what changed? Did somebody replace wiring or instrument transformers or other devices? Did somebody "calibrate" meter?
If it has never worked correctly, then you go back to the list for commissioning new installations.
This is fun stuff...
old field guy
RE: Metering testing
"The probability of error in selecting or connecting a kilowatthour meter is high, especially if instrument transformers are required."
We engineers tend to follow the Red Book.
Check everything with the utility and someone who knows metering, there's good advice above.
RE: Metering testing
RE: Metering testing
Thanks in advance.
RE: Metering testing
RE: Metering testing
Alan
RE: Metering testing
RE: Metering testing
Alan