C&S MRN3, Руководство пользователя

Страница: 20 / 28

2 0 2 0
2 0 2 0 2 0
6.5 Example of test circuit
For testing of the MRN3 MRN3 MRN3 MRN3 MRN3 relay, a three phase voltage
source with adjustable voltage and frequency is required
Figure 6.1 shows an example of a three-phase test circuit
energizing the
MRN3 MRN3 MRN3 MRN3 MRN3 relay during test. The three phase
voltages are applied to the relay in Y-connection.
For testing the vector surge function of the relay, a test
circuit which can produce phase angle change (vector
surge) is required to simulate mains failures (please refer
to chapter 6.5.6).
For testing the df/dt function of the relay, a special test
equipment is required, which produces a constant rate of
change of frequency.
6.5.1 Checking the input circuits and
measuring functions
Apply three voltages of rated value to the voltage input
circuits (terminals A3 - A8) of the relay. Check the
measured voltages, frequency and vector surge on the
display by pressing the push button <SELECT/RESET>
repeatedly. The displayed measuring voltages (shown in
Volt) are dependent on the wiring of the input voltage
converters and the set transformation ratio.
The voltages are indicated on the display in volts
At Y
At Y At Y At Y At Y-----connection: connection: connection: connection: connection:
z
Phase-to-neutral voltages: LED L1, L2, L3
At Delta-connection: At Delta-connection:
At Delta-connection: At Delta-connection:
At Delta-connection:
z
Phase-to-phase voltages: LED L1+L2, L2+L3,
L3+L1
The frequency is indicated on the display in Hz: LED f
(system frequency = 50.01Hz, Indication = 5001) The
vector surge is indicated on the display in degrees (for
MRN3-1 MRN3-1
MRN3-1 MRN3-1
MRN3-1 ): LED
ΔΘ
(Indication
ΔΘ
in °)
The rate of change of frequency (LED df) is indicated on
the display in Hz/s (for
MRN3-2 )
Change the voltages around the rated value and check
the measured voltages on the display. Change the system
frequency around the rated frequency and check the
measured frequency on the display.
Compare the voltage and frequency on display with the
signal on voltmeter and frequency meter. The deviation
for the voltage must not exceed 1% and for frequency <
<0.01 Hz.
By using an RMS-
RMS- RMS- RMS- RMS-metering instrument, a greater
deviation may be observed if the test voltage contains
harmonics. Because the
MRN3 MRN3 MRN3 MRN3 MRN3 relay measures only the
fundamental component of the input signals, the
5
E6
C6
D6
+
Blocking
input
External
Reset
E8 D8 C8
=
-
~
D9
E9
C9
L-/N
L+/L
L+/L L-/N L+/L
A7
A8
A5
A6
A4
A3
MRN1
U3E
U2E
U1E
~
~
~
L3
L2
Warning
Alarm
f
DQ
df/dt
u
E7
C7
D7
D5
C5
E5
E4
C4
D4
D1
D2
C1
E1
C2
E2
Trip Signal
selfsupervision
P
G
N
Serial Interface
v
Start
+
Timer
4
L1
N
Voltage Supply
P
G
N
3
2
1
-
-
Stop
1. Variable voltage source
with frequency regulation
2. Switching device
3. Voltmeter
4. Timer
5. Relay under test
Fig. 6.1 : T Fig. 6.1 : T Fig. 6.1 : T Fig. 6.1 : T Fig. 6.1 : Test circuit est circuit est circuit est circuit est circuit