EDR-5000
IM02602007E
Directional Features for Calculated (IR) Ground Fault Elements 50R/51R
All ground fault elements can be selected as »
Non-directional/Forward/Reverse« operated. This has to be done in the
»
Device Planning« menu.
For the direction detection, it is mandatory that the required voltages
exceed 0.35 V and the required currents exceed 10 mA. An exception is the
measured sensitive ground current which has to exceed 1 mA.
Important Definitions
Polarizing Quantity:
This is the quantity that is used as a reference value.
The
polarizing quantity can be selected by
the parameter »
IR Direction Control« in the [System Para/Direction] menu as follows:
»IR 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 [System Para/Direction] menu.
»IR IPol«: The measured neutral current (usually = IX) will be used as polarizing quantity.
»IR Dual«: For this method, the measured neutral current IPol=IX will be used as polarizing
quantity, if available, otherwise 3V0 will be used.
»IR Neg«: With this selection, the negative phase sequence voltage and current will be used
to detect the direction. The monitored current is still the calculated residual current IR.
Operating Quantity:
For the directional IR elements, the
operating quantity is in general the calculated neutral current
IR (except from »IR Neg« mode, where »I2« is the operating quantity).
The ground maximum torque angles (MTA) can be adjusted from 0° to 360°, except, if »
IR IPol« is selected. In this
case it is set to 0° (fixed).
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