Terminal Connectors in a Substation
Terminal Connectors in a Substation
(OP)
I'm working on a 69/13.2 distribution substation upgrade. On the Low side I'm connecting to two GIFU 15-01, 800:5 C.T.'s with a thermal rating of 1.5. (These C.T.'s are being supplied by the metering guys) The continuous current on the low side is 1093 Amps. These C.T.'s have flat tin plated Nema two hole Pads and I will be connecting to these C.T.'s with double 500 MCM to Nema 4 hole pad terminal connectors. This is a standard design and I'm wondering if there is any thermal concerns going from a 4 hole aluminum connector to a 2 hole connector on the C.T.?
Thanks






RE: Terminal Connectors in a Substation
Will cutting the connector void the approvals? Probably.
Will using just two of four connecting holes void the approvals? Probably.
Cutting two holes off the connector will result in a shorter current path and less heat generated in the connector.
I would first look for alternate hardware.
Bill
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"Why not the best?"
Jimmy Carter
RE: Terminal Connectors in a Substation
RE: Terminal Connectors in a Substation
When a four hole connector is connected to a two hole pad, the unused holes are often between the pad and the cables. The current generally flows past the two unused holes before arriving at bthe connection. Current is flowing trough an area where the design anticipated that it would already be transferring from the pad to the CT connector.
If it is possible to bolt it up close, good workmanship would indicating drilling two more holes and using four bolts.
My comments are directed at a straight connection. For a 90 deg. connection I agree with you completely.
Bill
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"Why not the best?"
Jimmy Carter
RE: Terminal Connectors in a Substation
We will be switching to a C.T. with a four hole pad, but we have a few stations currently with the 2 hole pad. My concern is, when dealing with equipment rated at 1200 amps the connection is commonly a 4 hole pad. This would lead one to believe, you need that amount of surface area provided to carry 1200 amps safely. Even though the low side has a maximum of 1093 Amps of rated continuous current, it is possible to overload this transformer. My question would be, is there a guide line or criteria on thermal characteristics through terminal connectors or do I need to start cranking out calculations?
Thanks,
RE: Terminal Connectors in a Substation
For an outdoor substation, though, the AL should be above the CU. This last part might be hard to achieve.
RE: Terminal Connectors in a Substation
Alan
RE: Terminal Connectors in a Substation
RE: Terminal Connectors in a Substation
Alan
RE: Terminal Connectors in a Substation
The sandwich solution seems to solve the problem at hand(If there actually was a problem?), but if anyone could think of some guide lines for connector construction and ampacity, it would be greatly appreciated.
Thanks
RE: Terminal Connectors in a Substation