other factors to achieve impedance values related to the primary system. The factor
k2
[Ω] will compensate for the series impedance Z
series
The healthy impedance measured at non-faulted conditions is referred to as the
reference impedance in further text.
In IED the measured impedance is compared to the reference impedance. In case of an
earth fault, the fault impedance is estimated and compared to the set values
RAlarm
and
RTrip
.
The measured values are transferred to the primary impedance values by taking the
actual impedance value through the complex transformation given by the equation.
1
2
true
measured
Z
k Z
k
= ×
+
GUID-20ADF3F6-6A89-4B5F-B0DA-9740C4FD5482 V1 EN
The factors
k
1
and
k
2
[Ω] are derived during the calibration measurements under
commissioning. As support for the calibration, the Injection Commissioning tool must
be used. This tool is an integrated part of the PCM600 tool.
In connection to this calibration, the reference impedance is also derived. In case of a
rotor earth fault with fault impedance
Z
f
, the measured admittance is:
1
1
1
1
1
1
ref
f
f
ref
Z
Z
Z
Z
Z
Z
=
+
=
=
-
EQUATION2405 V1 EN
The real part gives the fault conductance.
1
1
1
Re
f
ref
R
Z
Z
æ
ö
=
-
ç
÷
ç
÷
è
ø
EQUATION2421 V1 EN
RAlarm
and
RTrip
are the two resistance levels given in the settings. The values of
RAlarm
and
RTrip
are given in Ω.
An alarm signal ALARM is given after a set delay
tAlarm
if
R
f
<
RAlarm
A start signal START is given if
R
f
<
RTrip
See figure
1MRK502052-UEN B
Section 7
Impedance protection
289
Technical manual
Содержание Relion REG670
Страница 1: ...Relion 670 series Generator protection REG670 2 0 IEC Technical manual ...
Страница 2: ......
Страница 44: ...38 ...
Страница 58: ...52 ...
Страница 80: ...74 ...
Страница 106: ...100 ...
Страница 482: ...476 ...
Страница 548: ...542 ...
Страница 570: ...564 ...
Страница 600: ...594 ...
Страница 608: ...602 ...
Страница 630: ...624 ...
Страница 862: ...856 ...
Страница 1094: ...1088 ...
Страница 1226: ...1220 ...
Страница 1250: ...1244 ...
Страница 1297: ...1291 ...