Woodward HighPROtec MCDLV4, Руководство пользователя

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Supervision
LOP - Loss of Potential
Available elements:
LOP
Loss of Potential - Evaluating Measured Quantities
Ensure that the LOP has enough time to block faulty tripping of modules that use LOP.
That means, the delay time of the LOP should to be shorter than the tripping delay of
modules that use LOP.
In case of transformer protection relays the LOP element uses current and
voltage measured at the winding side determined by paramter:
[Field Para / VT / VT Winding Side ].
The LOP function detects the loss of voltage in any of the voltage input measuring circuits. Faulty tripping of
protective elements that take voltage into account can be prevented by means of this supervision element. The
following measured values and information to detect an Phase VT Failure condition:
•
Three-phase voltages;
•
Ratio of negative-to-positive sequence voltages;
•
Zero sequence voltage;
•
Three-phase currents;
•
Residual current (I0);
•
Pickup flags from all overcurrent elements; and
•
Breaker status (option)
After a set time delay time an Alarm »LOP.LOP B
LO
« will be issued.
1080 MCDLV4 DOK-HB-MCDLV4-2E