ABB Relion 650 Series Commissioning Manual page 62

Section 8
Commissioning and maintenance of the fault clearing system
handle is inserted or the IED is set to test mode from the local HMI. At the end of the
secondary injection test it should be checked that the event and alarm signalling is correct by
activating the events and performing some selected tests.
Self supervision check
Once secondary testing has been completed, it should be checked that no self-supervision
signals are activated continuously or sporadically. Especially check the time synchronization
system, GPS or other, and communication signals, both station communication and remote
communication, for example, the line differential communication system.
Trip circuit check
When the protection IED undergoes an operational check, a tripping pulse is normally obtained
on one or more of the output contacts and preferably on the test switch. The healthy circuit is
of utmost importance for the protection operation. If the circuit is not provided with a
continuous trip-circuit supervision, it is possible to check that circuit is really closed when the
test-plug handle has been removed by using a high-ohmic voltmeter and measuring between
the plus and the trip output on the panel. The measurement is then done through the tripping
magnet of the circuit breaker and therefore the complete tripping circuit is checked.
Trip circuit from trip IEDs to circuit breaker is often supervised by trip-circuit supervision. It
can then be checked that a circuit is healthy by opening tripping output terminals in the
cubicle. When the terminal is opened, an alarm shall be achieved on the signal system after a
delay of some seconds.
Measurement of service currents
After a maintenance test it is recommended to measure the service currents and service
voltages recorded by the protection IED. The service values are checked on the local HMI or in
PCM600. Ensure that the correct values and angles between voltages and currents are
recorded. Also check the direction of directional functions such as Distance and directional
overcurrent functions.
For transformer differential protection, the achieved differential current value is dependent on
the tap changer position and can vary between less than 1% up to perhaps 10% of rated
current. For line differential functions, the capacitive charging currents can normally be
recorded as a differential current.
The zero-sequence current to earth-fault protection IEDs should be measured. The current
amounts normally very small but normally it is possible to see if the current circuit is "alive".
The neutral-point voltage to an earth-fault protection IED is checked. The voltage is normally
0.1 to 1V secondary. However, voltage can be considerably higher due to harmonics. Normally a
CVT secondary can have around 2.5 - 3% third-harmonic voltage.
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Note, that the breaker must be closed.
Please observe that the test system does not have its built-in security during
this test. If the instrument should be set on Amp instead of Volts, the circuit
breaker naturally is tripped, therefore, greatest care is necessary.
However, remember to close the circuit directly after the test and tighten the
terminal carefully!
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Busbar protection REB650
Commissioning manual