Primary Injection Testing; Secondary Injection Testing; Phase Current Input Functions - GE 169 Instruction Manual

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GE Power Management
4 RELAY TESTING

4.1 Primary Injection Testing

Prior to relay commissioning at an installation, complete system operation can be verified by injecting current
through the phase and ground fault CTs. To do this a primary (high current) injection test set is required.
Operation of the entire relay system, except the phase CTs can be checked by applying input signals to the 169 relay
from a secondary injection test set as described in the following sections.

4.2 Secondary Injection Testing

Single phase secondary injection testing can be performed using the test set up shown in figure 4-1. Tests should
be performed to verify correct operation of relay input (A/D), output, memory, and RTD circuitry. 169 relay functions
are firmware driven and thus testing is required only to verify correct firmware/hardware interaction.
All tests described in the following sections will be applicable with factory setpoints and configurations left
unchanged. Similar tests can be performed after new setpoints have been stored in the 169 relay.
NOTE: A three phase test set or an actual installation test is required to test the phase reversal function.

4.3 Phase Current Input Functions

All phase current functions use digital current information converted from the analog phase CT inputs. Functions
that use phase current readings are overload, unbalance, short circuit, rapid trip, and phase reversal. The 169 must
read the injected phase currents correctly in order for these functions to operate correctly. To determine if the relay
is reading the proper current values inject a phase current into the relay and view the three current readings in
ACTUAL VALUES mode, page 1. With factory setpoints stored in the relay the displayed current should be:
displayed current = actual injected current X 100/5 (phase CT ratio)
Various trip and alarm conditions can be simulated by adjusting the injected phase currents. All trip/alarm conditions
using phase current readings will operate as described in Section 3 providing the 169 relay reads the correct phase
current.
To simulate an overload condition turn to "ACCEL. TIME=" to "off" (SETPOINTS, page 1) and inject a current of 9
Amps in all three phases. This will be read by the relay as:
displayed current = 9 Amps X 100/5 = 180 Amps
which is two times the Full Load Current setpoint of 90 Amps. The trip output relay should activate after a time of
117 seconds which is the time to trip for a 200% overload using curve #4. This time may be less due to the charging
of thermal memory because of the presence of unbalance or previous overloads. Thermal memory may be
discharged to 0% by shorting together the Emergency Restart terminals (54, 55) momentarily.
To check the displayed negative to positive sequence unbalance ratio inject currents of 5.0 Amps, 5.0 Amps and 3.9
Amps into the relay and examine the "UNBALANCE RATIO (In/Ip)". The reading should be 15%. Other unbalance
conditions can be checked by calculating the negative to positive sequence current ratio for the injected phase
currents and comparing this to the ACTUAL VALUES display.
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