Main Menu:
This selection will return the controller to the
Main Menu:
Dynamic Frequency Operation
The MPRT can be programmed with the TVI to perform dynamic timing test on all under/over
frequency relays either electro-mechanical or solid-state, single or multi-set point. To test a
typical multi-set point, solid-state under frequency relay, the following procedure applies.
1.
In the Prefault setting window, select V1. The Magnitude and Frequency values should
already be set to the default normal Line Frequency and voltage values. If not, select the
appropriate value(s) and change them using the touch screen and numeric keypad. Set
the Duration Time by using the touch screen and numeric keypad. Time indicated is in
seconds. This time is the desired time which the output voltage and frequency will
remain at the Prefault stage before switching to the Fault stage.
2.
Select Fault values by pressing the Fault Settings button. Set the desired FAULT
Frequency, normally a value below (under frequency) or above (over frequency) the Tap
or Setting value, by using the touch screen and keypad. This is the frequency that the
output will delta or step down to during the Fault stage. For doing a timing test enter the
appropriate Duration Time for that fault frequency (the Duration time needs to be slightly
longer than the expected trip time of the relay under test).
3.
Set the desired TIMER Start Frequency. If using a ramping frequency output, when the
output frequency ramps through the TIMER Start Frequency the TIMER will start. If
using a Step Function, the TIMER Start Frequency must be equal to the FAULT
Frequency.
4.
Select Postfault values by pressing the Postfault Settings button. Set the desired
Postfault Frequency using the touch screen and keypad. This provides a go/no go test
for relays that should instantly reset once the frequency conditions (postfault) have
stabilized to the prefault conditions. Set a Duration Time long enough that the user can
easily determine that the relay has reset properly.
5.
With the relay trip circuit connected to the appropriate binary input, Timer STOP gate,
binding posts, select the appropriate TIMER Stop gate using the Timer Setup screen.
Select the TIMER Start/Stop LATCH ON both the START and STOP circuits. NOTE:
Failure to LATCH circuits will result in timing error.
6.
The unit defaults to a frequency Step for dynamic timing tests. For testing relays with
multiple set points, the user may want to use either Hz/Sec or Ramp. Hz/Sec allows
different ramp rates down/up, while the Ramp uses the same frequency rate of change
for both ramps. Set the Delta 1 rate of change (Ramp Rate 1). For example, if you wish
to ramp the output frequency at .1 hertz per second, then press the appropriate touch
Delta 1 window and set the frequency to 0.10 Hz/Sec using the numeric keypad.
7.
If using Hz/Sec, set the Delta 2 rate of change (Ramp Rate 2) similarly to the Delta 1.
8.
Press the Start button window. The voltage output frequency will begin to delta (or step)
down after the Prefault Duration time expires. When the relay trip signal is sensed, the
output will de-initiate and the TIMER will stop indicating the trip time.
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