Negative Sequence Voltage to DFR
Negative Sequence Voltage to DFR
(OP)
We have a client that is interested in taking a negative sequence voltage measurement back to their DFR. From looking at their schemes, they don't appear to have any relay or device capable of producing a negative sequence voltage output for use by the DFR.
1. Does anyone know of an old electromechanical relay (since that all that is installed off of the PTs) that would have such an output.
2. Is there a relatively cheap option for installing some sort of negative sequence filter/transducer?
Thanks for the input.
1. Does anyone know of an old electromechanical relay (since that all that is installed off of the PTs) that would have such an output.
2. Is there a relatively cheap option for installing some sort of negative sequence filter/transducer?
Thanks for the input.






RE: Negative Sequence Voltage to DFR
RE: Negative Sequence Voltage to DFR
RE: Negative Sequence Voltage to DFR
RE: Negative Sequence Voltage to DFR
RE: Negative Sequence Voltage to DFR
RE: Negative Sequence Voltage to DFR
RE: Negative Sequence Voltage to DFR
RE: Negative Sequence Voltage to DFR
RE: Negative Sequence Voltage to DFR
I don't think your SEL solutions meet the OP's requirement number 1.
Sorry if I confused the issue with the word "analog." I didn't mean to imply the OP required a DC current loop. I assume the dfr would accept a secondary AC voltage level at its inputs (analog of the primary voltage, and not a digital input).
The figure I referenced is in the older Westinghouse version of the book also.
RE: Negative Sequence Voltage to DFR
RE: Negative Sequence Voltage to DFR
I suppose that if one were daring, one could dig into a BE1-47N and try to find the output of the phase shifting network, but it would probably be at a very low level that would need to be amplified to go into the DFR.
RE: Negative Sequence Voltage to DFR
Since it is a DFR, the signals are probably not going to be used for real time protection or control.
Is there a benefit to having a real time recording of negative sequence voltage?