electro mechanical relays
electro mechanical relays
(OP)
What is the difference between a HCB relay, and a PMA relay? Don't the both monitor pilot wires between substation?
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electro mechanical relays
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RE: electro mechanical relays
HCB:
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The type HCB relay is a high speed pilot wire relay designed for the complete phase and ground protection of two and three terminal transmission lines.
PMA:
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Type PM and PMA Monitoring Relays provide continuous monitoring of a pilot-wire circuit to detect open circuits, short circuits, grounds, and wire reversal.
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RE: electro mechanical relays
If memory serves me right, you need both an HCB and a PM-1 at each end (4 relays). I remember the HCB takes the input of the three phase currents at one end. The PM-1 somehow helps with the interface and transfer trip function.
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