Function - DOLD RN 5897/020 Mode D'emploi

Function

The device is supplied with DC auxiliary voltage via terminals A1(+) / A2.
Switching on the auxiliary voltage (Power-On) is followed by an internal
self-test for 12 s (see „Device test functions"). The test process is visible
in the display. After this, measurement of the insulation resistance in the
measuring circuits begins and the the colour of the backlight changes
into green.
Measuring circuit
(Insulation measurement between terminals L(+) / L(-) and PE1/PE2)
The insulation monitor RN 5897/020 can be operated either with or without
coupling device. Max. mains voltage and connection diagrams have to
be observed!
If the insulation monitor is operated without coupling device the terminals
L(+) and L(-) have to be connected directly to the voltage system to be
monitored. and the terminals VSG1/L(+) and VSG2/L(-) each have to be
bridged (see also operation with coupling device).
A broken wire detection that can be disabled provides a fault signal if both
terminals L(+) and L(-) are not linked by the connected network.
The type of network (AC, DC, 3NAC) has to be selected.
Also the terminals PE1 and PE2 have to be connected with 2 separate
wires to the protective earth. An interruption of a wire also causes a fault
signal (see section "Behavior on faulty connection"). The monitoring of
the PE connection cannot be de-activated.
To measure the insulation resistance an active measuring voltage with
changing polarity is connected between L(+)/L(-) and PE1/PE2.The
momentary polarity of the measuring cycle is shown on the display by 2
curser segments („MP+" for positive phase and „MP-" for negative phase).
At the end of a measuring cycle the actual insulation resistance is produced
and indicated. The actual value is shown on the display. The relays for alarm
K1 and pre-alarm K2 switch when dropping under the adjusted response
values. In addition the backlight of the display changes to orange color
on pre-alarm or to red color on alarm. An asymmetric earth fault either to
„+" or „-" is also indicated on the display (only in DC- systems or with a
fault on the DC-side of a system).
Manual reset of fault message
Using the display menu in programming mode, the manual reset function
for insulation failures can be selected. If manual reset is activated the
insulation fault signals of the measuring circuit are stored when dropping
under the adjusted response values also if the insulation resistance goes
back to healthy state. The minimum value is stored and can be shown
on the display. Pressing the „Reset" button on the front side for 2 s, the
alarm signal and the stored minimum value are reset if the actual insulation
resistance is in healthy state.
Indicator relay for insulation fault signal
For the indicator relays K1 (contacts 11-12-14, for alarm) and K2 (contacts
21-22-24, for pre-alarm) the function can be set in programming mode to
energized on trip or de-energized on trip when the insulation resistance
drops below the adjusted response value.
The status of the indicator relays is shown on the display with the two cursor
segments "K1" and "K2". When the relay is energized, the corresponding
curser lights up.
Disable the measuring function
Using the external control input X1/X2 the measuring function of the
RN 5897/020 can be disabled. This could be used when several isolated
voltage systems with individual insulation monitors need to be coupled.
The measuring voltage is set to -90V (negative measuring phase) and the
evaluation of the measurement is stopped. The status of the output relays
is frozen and not changed any more. If the measurement is disabled the
colour of the display changes to orange and the text "Stop!" is displayed.
Please be aware, only the evaluation of the measurement is stopped and
the measuring pulse is interrupted! A high resistive disconnection to PE
does not take place (see internal resistance).
Function
Broken wire detection
As described in section "Measuring circut", the measuring circuits L(+)/L(-)
and the protective conductors PE1/PE2 are constantly monitored for wire
breaks – not only at Power-On or a manual or occasional automatic test.
The response time of monitoring is only a few seconds. Broken wire
detection between L(+) and L(-) is performed via coupled alternating
voltage. This alternating voltage is short-circuited if the terminals are
connected to the connected mains at low-resistance. The device detects
that the mains to be monitored is properly connected.
Since this broken wire detection is carried out with alternating voltage, large
capacitances should be avoided between L(+) and L(-), since the capacitive
reactance of these capacitances also short-circuits this alternating voltage.
The device would no longer detect a connection fault on L(+)/L(-).
Especially parallel lines should be prevented over larger distances.
If larger capacitances between L(+)/L(-) cannot be avoided or if the coupled
alternating voltage interferes with the system, the broken wire detection can
be de-activated using the display menu in programming mode. Monitoring
deactivated, monitoring only during device test or continuous monitoring
(every 2 minutes for 10 s) are the possible options. If the broken wire
detection on L(+)/L(-) is de-activated no AC voltage is injected.
The broken wire detection on PE1/PE2 cannot be de-activated.
Device test functions
Principally, 2 different test functions are implemented: The "self-test" and
the "expanded test":
The self-test of the device is performed automatically after Power-On and
every full operating hours. It can also be triggered manually at any time by
pressing the "Test" button at the device front for 2 s.
With the self-test, contrary to the expanded test, the status of the Indicator
relays is not affected; the sequence is as follows:
The display backlight colour changes into orange. For approx.. 2 s all pixels
and segments of the LCD are shown. After that the text "Test1" comes up
and the measuring pulse is switched for approx. 5 s to negative test phase.
The polarity of the test voltage is also indicated on the display by curser
segments. Within these 5 s the internal measuring circuit is checked for
failures. Then the measuring pulse is switched for approx. 5 s to positive
test phase and more internal tests take place. If no failures turned up and
had been recognized, the measurement continuous. The extended test
procedure is started when during or at the end of the above described
12 s self-test the test button is pressed again for 2 s.
The sequence is similar to the self-test (2 measuring phases of 5 s each) but
in addition the output relays go in alarm stated. The display shows "Test2".
The test phases of the extended test will be repeated continuously. The
extended test can be finished after the first complete sequence (approx.
10 sec) by pressing the "reset" button for 2 seconds. The device starts
the insulation monitoring again.
U
Self test (Test 1)
Insulation
measurement measurement
Duration: approx. 12s
Positive
Measuring voltage
Negative
1)
Test signal
2)
Reset signal
Alarm
Relay state K1 and K2
No Alarm
Test signal: Button Test > 2 s or X1/X2 > 1.5 s and < 10 s
1)
Reset signal: Button Reset > 2 s or X1/X2 < 1.5 s
2)
To initiate the extended test (Test 2) the test signal must be operated
3)
within the self test (Test 1) again.
The reset signal has here no function, as the first complete sequence
4)
of extended test (Test 2) is not finished.
22
Self test (Test 1) Continuous extended
Insulation
Duration: approx. 12s test (Test 2)
Duration: approx. 10s
3)
4)
RN 5897/020 / 13.07.22 en / 605A
Insulation
measurement
t
M12462