TB XRN2 02.00 E
29
7.4.3
Checking the input circuits and mea-
suring functions
Apply three voltages of rated value to the voltage input
circuits (terminals L1, L2, L3, N1, N2, N3) of the re-
lay. Check the measured voltages, frequency and vec-
tor surge on the display by pressing the push button
<SELECT/RESET> repeatedly.
The voltages are indicated on the display in volts
At Y-connection:
•
Phase-to-neutral voltages: LED L1, L2, L3
At Delta-connection:
•
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
XRN2-1
): LED
∆Θ
(Indication
∆Θ
in °)
The rate of change of frequency (LED df) is indicated
on the display in Hz/s (for
XRN2-2
)
Change the voltages around the rated value and check
the measured voltages on the display.
Change the system frequency around the rated fre-
quency and check the measured frequency on the dis-
play.
Compare the voltage and frequency on display with
the signal on voltmeter and frequency meter. The devia-
tion for the voltage must not exceed 1% and for fre-
quency <0.01 Hz.
By using an RMS-metering instrument, a greater devia-
tion may be observed if the test voltage contains har-
monics. Because the
XRN2
relay measures only the
fundamental component of the input signals, the har-
monics will be rejected by the internal DFFT-digital fil-
ter. Whereas the RMS-metering instrument measures the
RMS-value of the input signals.
7.4.4
Checking the operating and resetting
values of the over/undervolt-age
functions
Note:
When the measuring voltage is connected or discon-
nected, vector surge tripping or df/dt tripping can oc-
cur. In order to ensure a trouble-free test procedure, the
vector surge function or df/dt function of the relay have
to be blocked before tests are started.
Apply three voltages with the rated value and gradually
increase (decrease) the voltages until the relay starts,
i.e. at the moment when the LED U> (or U<) lights up
or the voltage alarm output relay (contact ter-
minals 31/34 and 41/44) is activated. Read the op-
erating voltage indicated by the voltmeter. The devia-
tion must not exceed 1% of the set operating value.
Furthermore, gradually decrease (increase) the voltages
until the relay resets, i.e. the voltage alarm output relay
is disengaged. Check that the dropout to pickup ratio
for voltage is greater than 0.97 (for overvoltage func-
tion) or smaller than 1.03 (for undervoltage).
7.4.5
Checking the relay operating time of
the over/undervoltage functions
To check the relay's operating time, a timer must be
connected to the trip output relay contact (Contact ter-
minals D1/E1). The timer should be started simultane-
ously with the voltage change from sound condition to
a faulty condition and stopped by the trip relay con-
tact. The operating time measured by timer should have
a deviation about 3% of the set value or <20 ms.
7.4.6
Checking the operating and resetting
values of the over/underfre-quency
functions
Note:
Due to frequency changes, vector surge tripping or
df/dt tripping can occur during frequency tests. In or-
der to ensure a trouble-free test procedure, the vector
surge function or df/dt function of the relay have to be
blocked before tests are started.
During frequency tests, each of the frequency elements
should be tested separately. This makes it necessary
that the other frequency elements of the relay have to
be blocked by setting the frequency pickup values
f
1
- f
3
to "EXIT". For testing the pickup and dropout to
pickup values, the test frequency has to be increased
(decreased) until the relay is engergized. This is indi-
cated by lighting up of LEDs f
1
- f
3
.
When comparing the values displayed with those of
the frequency meter, the deviation must not exceed
0.01 Hz. The dropout to pickup values are ascertained
by increasing (decreasing) the test frequency slowly un-
til the output relay releases.
The dropout to pickup value for overfrequency must be
>0.99, and for underfrequency <1.01.
Summary of Contents for XRN2
Page 1: ...XRN2 Mains decoupling relay ...
Page 40: ...40 TB XRN2 02 00 E ...