Simulation - GE 750 Instruction Manual

S8 Testing

Simulation

SIMULATION
CAUTION
GE Multilin
a) Main Menu
PATH: SETPOINTS S8 TESTING
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When in Simulation Mode, the normal protection and control features are
not operational. This is indicated by the 8 Self-Test Warning relay being de-
energized. If Simulation Mode is used for field testing on equipment, the
operator must provide other means of protection and control.
A simulation feature is provided for testing the functionality of the relay in response
to program conditions, without the need of external AC voltage and current inputs.
First time users will find this to be a valuable training tool. System parameters such
as currents and voltages, phase angles, and system frequency are entered as
setpoints. When placed in simulation mode, the relay suspends reading actual AC
inputs, generates samples to represent the programmed phasors, and loads these
samples into the memory to be processed by the relay. Both normal and fault
conditions can be simulated to exercise a variety of relay features. There are three
sets of input parameters used during simulation, each providing a particular state of
the system, as shown below:
• Prefault State: This state simulates the normal operating condition of a feeder
carrying load current, by replacing the normal input parameters with
programmed prefault values. Voltages are automatically set to the nominal
value programmed in the
neutral current is set to zero. Phase currents are balanced and set to the value
programmed in the
PREFAULT PHASE A/B/C CURRENT
each phase current relative to its corresponding phase neutral voltage is set to
the value programmed in the
frequency of voltages and currents are automatically set to the values
programmed in the
NOMINAL FREQ
• Fault State: This state simulates the faulted operating condition of a feeder by
replacing the normal prefault feeder input parameters with programmed fault
values. The magnitude and angle of each bus voltage and current, polarizing
current, system frequency and analog input are set to the values programmed
under the
FAULT VALUES
vector sum of the phase currents, and 3V
voltages.
• Postfault State: This state is intended to simulate a feeder that has tripped.
Current is automatically set to 0 A. Bus voltages are automatically balanced and
set to Phase A-N at 0°, B-N at 120°, and C-N at 240°. The bus voltage
magnitude and frequency are set to the entered values. The synchronizing
voltage is set to the entered values of magnitude, angle (with respect to phase
A-N bus voltage) and frequency.
There are two methods of running simulations. If the feeder circuit breaker is
connected to the relay and can be opened and closed, a full operating sequence can
be performed. If a breaker is not available, as is often the case, the relay can be
made to simulate a breaker and allow the 760 to exercise its autoreclose feature.
The operation of each method is described below.
1. If simulation of the feeder breaker is required set the
setpoint to "Enabled". After the required simulation setpoints have been
entered, the relay is placed in the Prefault State by setting the
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SIMULATION
SETUP [ ]
See page 5–136.
PREFAULT [ ]
See page 5–137.
VALUES
FAULT [ ]
See page 5–137.
VALUES
POST FAULT [ ]
See page 5–138.
VALUES
BUS VT NOMINAL SECONDARY VOLTAGE
PREFAULT PWR FACTOR ANGLE
setpoint.
setpoints. The neutral current is calculated from the
from the vector sum of the phase
0
750/760
Feeder Management Relay
setpoint. The
setpoint. The phase angle of
setpoint. The
CIRCUIT BRKR SIMULATION
SIMULATION STATE
5–135