13.6.6 100% Stator ground fault protection, 3rd harmonic based
STEFPHIZ (59THD)
SEMOD158990-3 v4
Prepare the IED for verification of settings outlined in Section "Preparing the IED to
verify settings".
13.6.6.1 Testing
SEMOD158990-8 v3
The protection function uses measurement of the third-harmonic voltages in the neutral
point of the generator and on the generator terminal (broken delta voltage transformer
connection to the IED).
The test set shall be capable to generate third-harmonic voltages. One voltage (V
N3
) is
connected to the residual voltage input related to the terminal side of the generator. The
second voltage (V
N3
) is connected to the voltage input related to the neutral of the
generator. The angle between the injected third-harmonic voltages shall be adjustable.
en07000127_ansi.vsd
V
3N
V
3T
ANSI07000127 V1 EN-US
Figure 61: Typical phasor diagram for third harmonic voltages for healthy machine
1. Inject the following voltages: V
3T
= 15 V, V
3N
= 5 V and the angle between the
voltages = 180°. Check the monitored values of the following analogue signals:
E3 (the magnitude of the third-harmonic induced voltage in the stator), V
3N
: 5 V
(the magnitude of the third-harmonic voltage measured at the neutral side of the
generator), V
3T
: 15 V (the magnitude of the third-harmonic voltage measured at
the terminal side of the generator) and ANGLE: 180° (the angle between the
third-harmonic voltage phasors V
3N
and V
3T
). The value of E3 should be close to
the following value:
1MRK 502 073-UUS A Section 13
Testing functionality by secondary injection
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062 229
Commissioning manual
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