Operation Principle - ABB REG670 Technical Manual

1MRK502052-UEN B
7.8.9
Technical manual

Operation principle

The protection principle is based on injection of voltage to the exciter point of the field
circuit.
Uinj
7
I
U
REX060/ RIM module
REG670
Generator Protection Panel
IEC11000014 V1 EN
Figure 125: Example installation for rotor injection
1 Generator unit consisting of a synchronous generator and a step-up transformer
2 Generator field winding
3 Capacitor coupling unit which is used to provide insulation barrier between rotor circuit and injection
equipment
4 Cable used to inject the square-wave signal into the rotor circuit
5 Connection for measurement of injected current. This signal is amplified in REX060 before it is
passed on to IED for evaluation.
6 Connection for measurement of injected voltage. This signal is amplified in REX060 before it is
passed on to IED for evaluation.
7 Two VT inputs into IED which are used to measure injected current and voltage
8 Protection for excessive over-voltages posed by generator. REX060 can withstand without damage
maximum voltage of 120V and when used together with REX062 up to 240V.
The injection signals are generated in a separate unit, REX060. The signals have
square wave form and are injected to the generator via the coupling capacitor unit
REX061 to the excitation circuit.
In the REX060 unit the injection voltage and current signals are amplified to a level
adapted to the analogue voltage inputs of IED. In IED the measured signals evaluated
to detect rotor earth faults.
8
U>
Rshunt
5
6
Section 7
Impedance protection
4
3
R C
REX061
2
IEC11000014-4-en.vsd
Step-up
Transformer
1
~
Generator
R
N
285