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Overfrequency or underfrequency elements FRQ1 to FRQ6
• Enter the signal number to observe the operation at the monitoring jack A as shown in
Section 6.5.1.
• Apply a rated voltage and frequency as shown in Figure 6.5.12.
In case of overfrequency characteristic,
• Increase the frequency and measure the value at which the element operates. Check that the
measured value is within ± 0.005Hz of the setting.
In case of underfrequency characteristics,
• Decrease the frequency and measure the value at which the element operates. Check that
the measured value is within ± 0.005Hz of the setting.
Undervoltage block test, FRQBLK
• Apply a rated voltage and change the magnitude of frequency to operate an element.
• Keep the frequency that the element is operating, and change the magnitude of the voltage
applied from the rated voltage to less than FRQBLK setting voltage. And then, check that
the element resets.
6.5.1.12 Voltage and Synchronism Check Elements
The testing circuit is shown in Figure 6.5.13.
+
Single-phase
voltage
−
source
V
+
Single-phase
voltage
−
source
+
DC
power
−
supply
+
DC
voltmeter
−
Figure 6.5.13 Voltage and Synchronism Check Element Test Circuit
The output signal of testing element is assigned to the monitoring jack A.
Voltage and synchronism check elements and their output signal number are listed below.
Measuring element
OVR
UVR
V
φ
Signal number
280
278
⎯
⎯
267
6 F 2 S 0 8 4 2
GRD150
TB1 -11
V I
-12
-17
V R
Monitoring
-18
jack
TB4 -18
-19
-20
(E)
A
0V
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