34
ANSI MEDIUM VOLTAGE METAL-CLAD DIGITAL SWITCHGEAR
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68
—
69
—
68 Changing correction
factors for amplitude
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69 Changing correction
factors for angle
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Secondary testing of protection relays
In comparison with traditional switchgear, the
overall testing procedure of protection relays has
not changed. Protection and metering functions
of the protection relay are tested with a
secondary injection tester. It is assumed that
protection relays are loaded with the final
settings. We recommend testing protection relay
metering functionality (U, I, P, cos φ, E) as a part
of secondary injections. To get the best
performance of the protection relays, simulate a
real network by means of running two sequences
– Pre-fault for at least 1 second and Fault.
Notice:
Testers for secondary injections do not
support the amplitude and phase angle
correction factors of sensors. Therefore, it is
recommended to set default values of current and
voltage sensors for testing.
On the protection relay LHMI go to
-> Main Menu/
Configuration/Analogue inputs/Current (3I, CT)
and Voltage (3U, VT)
• Amplitude Corr x = 1.0000 (default)
• Angle Corr x = 0.0000 deg (default) where “x”
represents A, B or C phase
NOTICE
