ABB Relion 670 series, Installation And Commissioning Manual

Page: 205 / 260

15.7.6.1 Testing
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
(U
N3
) is connected to the residual voltage input related to the terminal side of the
generator. The second voltage (U
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.vsd
U
3N
U
3T
IEC07000127 V1 EN
Figure 100: Typical phasor diagram for third harmonic voltages for healthy
machine
1. Inject the following voltages: U
3T
= 15 V, U
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), U
3N
: 5 V (the magnitude of the third-harmonic voltage measured at
the neutral side of the generator), U
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 U
3N
and U
3T
). The value of E3 should be close to the following value:
( ) ( )
2 2
3N 3T 3T
E3 U U cos(ANGLE) U sin(ANGLE)
= - × + ×
EQUATION2070 V1 EN
(Equation 13)
2. Read the value of DU (differential voltage). The value of DU should be close
to the following value:
( ) ( )
2 2
3N 3T 3T
DU U U cos(ANGLE) U sin(ANGLE)
= + × + ×
EQUATION2071 V1 EN
(Equation 14)
3. Decrease the value of the injected voltage U
3N
until the signal START3H is
activated. Check that
1MRK 502 029-UEN A
Section 15
Verifying settings by secondary injection
199
Installation and commissioning manual