Woodward HighPROtec MCDLV4, Руководство пользователя

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Module: Protection (Prot)
Directional Features for Measured Ground Fault Elements 50N/51N
All ground fault elements can be selected as »n
on-directional/forward/reverse« operated. This has to be done in
the »
Device Planning« menu.
Important Definitions
Polarizing Quantity: This is the quantity that is used as a reference value.
The polarizing quantity can be selected
by the parameter » IG meas dir ctrl« in the [Field Para/Direction] menu as follows:
»IG meas 3V0«: The neutral voltage selected by the parameter »3V0 Source« will be used
as the polarizing quantity. The traditional way to polarize a ground fault element is to use
neutral voltage (3V0). The neutral voltage can, however, be either »
measured« or
»
calculated«. This can be selected by the parameter »3V0 Source« in the
[Field Para/Direction] menu.
»I2,V2«: With this selection, the negative phase sequence voltage and current (Polarizing:
V2/Operating: I2) will be used to detect direction. The monitored current is still the
measured residual current IG meas.
»Dual«: For this method, the negative phase sequence voltage »V2« will be used as
polarizing quantity if »
V2« and »I2« are available, otherwise 3V0 will be used. The
operating quantity is either I2 if »
V2« and »I2« are available, else IG meas.
The following table gives the User a quick overview of all possible directional settings.
50N/51N Direction Decision
by Angle Between:
[Field Para/
Direction]
The Following Angle
Has to Be Set:
[Field
Para/Direction]:
IG meas dir ctrl =
[Field
Para/Direction]:
3V0 Source =
Measured ground current and neutral voltage:
IG meas, 3V0 (measured)
Ground MTA IG meas 3V0
measured
Measured ground current and neutral voltage:
IG meas, 3V0 (calculated)
Ground MTA IG meas 3V0
calculated
Negative sequence voltage and current
I2, V2 90° + Phase MTA I2,V2 not used
Negative phase sequence current and
voltage (preferred), measured ground current
and neutral voltage (alternatively):
I2, V2 (if available)
or else:
IG meas, 3V0 (measured) If V2 and I2 are
available:
90° + Phase MTA
else:
Ground MTA
Dual measured
Negative phase sequence current and
voltage (preferred), measured ground current
and neutral voltage (alternatively):
I2, V2 (if available)
or else:
IG meas, 3V0 (calculated)
If V2 and I2 are
available:
90° + Phase MTA
else:
Ground MTA
Dual calculated
492 MCDLV4 DOK-HB-MCDLV4-2E