If a particular stable operating condition of the generator requires a dedicated reference
impedance, it can be defined and saved by the Commissioning tab of ICT.
Up to five reference impedances can be defined for the protection function
STTIPHIZ.
The first reference impedances is defined during the calibration.
ICT also performs a verification between the new reference impedance(s) and existing
reference impedance(s), and warns the user if the resulting estimated resistance difference
could cause alarm or trip when one reference is shifted from another during operation.
If more than one reference impedance is to be used, a logic must be configured to detect such
changes in the operating conditions and enable the related reference impedance. For example,
a logic can be based on the following conditions in order to select the active reference
impedance automatically:
1.
Generator voltage < set value and generator circuit breaker open: Reference impedance 1
2.
Generator voltage > set value and generator circuit breaker open: Reference impedance 2
3.
Generator voltage > set value and generator circuit breaker closed: Reference impedance 3
For more information see separate application note
1MRG005030 Application example for
injection based 100% Stator EF and Sensitive Rotor EF protection.
Monitoring
The Monitoring tab of ICT offers the possibility to monitor several quantities during tests as
well as in normal operating condition in order to evaluate the behavior of the protection
function. It can help in the identification of the operating conditions, where change of
reference impedance is required.
Auditing
In the auditing part installation, calibration and commissioning reports are stored.
7.3
Launching injection commissioning tool (ICT) and
performing the installation
GUID-7CDFB043-26E1-4169-9D2C-BE7C5C08AEAE v3
1.
Make sure you have not connected any additional impedance in parallel with the stator
circuit. All wirings shall be finalized and they shall be the definitive ones. All primary and
secondary devices shall be connected and switched on. All grounding of generator shall
be removed. The generator shall be in a condition that is as close as possible to the
normal operating condition.
2.
Activate the injection by turning the injection switch to on position on the injection unit
REX060.
3.
To launch the Injection commissioning tool (ICT), right-click REG670 in the PCM plant
structure and select the Injection commissioning.
4.
In the ICT toolbar, select the 100% Stator Earth Fault function.
1MRK 502 067-UEN B
Section 7
Calibrating injection based 100% stator earth fault protection
65
Commissioning manual
