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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