IG-267-EN versión 01; 07/04/2017
70
Protection, metering and control models General Instructions
ekor.rpa
The earth unit setting depends on the characteristics of the
line where the unit is installed. In general, the earth fault
values are high enough to be detected as overcurrent.
Even in isolated or resonant earthed neutral networks, the
fault value in transformer protection installations is clearly
different from the capacitive currents of the lines. The values
of the setting parameters must guarantee selectivity with
the main switch protections. Given the variety of protection
criteria and types of neutral used in the networks, a single
parameterisation cannot be indicated; each case requires a
specific parameterisation. For transformers up to 2000 kVA,
the settings below are given as a general example. It must
be ensured that they properly apply to the protections
upstream (general, line or main switch protections, among
others.)
Unit Type Designation Value
Phase timed unit (1)
(UNIT_51)
Enabling the unit Enable ON
Starting up the unit Pick_up* 58 (A)
Time curve Curve EI
Inverse curve time index Index 0.20
Fixed time Time ---
Torque control Direction OFF
Phase instantaneous unit (1)
(UNIT_50)
Enabling the unit Enable ON
Starting up the unit Pick_up 404 (A)
Unit timing Time 0.40 (s)
Torque control Direction ---
Sensitive neutral timed unit
(1)
(UNIT_51NS)
Enabling the unit Enable ON
Starting up the unit Pick_up 2 (A)
Time curve Curve NI
Inverse curve time index Index 0.20
Fixed time Time ---
Torque control Direction OFF
Sensitive neutral
instantaneous unit
(UNIT_50NS)
Enabling the unit Enable ON
Starting up the unit Pick_up 10 (A)
Unit timing Time 0.40 (s)
Torque control Direction OFF
Table 8.6. Settings
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