3.8 Protection against maloperation / interlock
dependencies (Figures 6/2, 6/5 and 7/1)
3.8.1 Interlocks in general
In order to prevent hazardous situations and
maloperation, a series of interlocks are provided
to protect the operators and the switchgear itself.
•
Protection against maloperation can be
implemented by the multifunction protection
and switchbay control unit REO 517
The circuit-breaker and three position switch can
be controlled directly at the panel and/or remotely,
for instance from the control room. Operation at
the panel is by selection on the REO 517 or
conventionally with push buttons and bar-type
annunciators in the mimic diagram.
•
Three position switch UX2TE-R and the
corresponding circuit- breaker type VD4 X-R are
electrically interlocked
-
In the case of manual operation of the three
position switch, a mechanical interlock can
become effective (optional)
•
Details of further interlocks/dependencies, e.g.
with neighbouring systems, can be found in the
relevant order documents for the system
concerned
•
The interlock polling (electrical only) between
panels, where implemented, is effected by loop
lines from panel to panel
Operation on failure of auxiliary power:
On failure of the auxiliary power, the devices can
be operated manually.
The details for the specific system are also to be
observed.
Where no mechanical interlock or optional interlock
is fitted, intervention in the interlock concept is
possible by opening the control cabinet door.
Emergency manual operation is possible by means
of a hand crank and mechanical push button.
Note
Perform all switching operations fully until the
defined limit position is reached!
•
Switch off the mcbs for the circuit breaker
release circuit and operating mechanism of
the three position switch
3.8.2 Function of the interlock between the circuit
breaker and the three-position switch
3.8.2.1 Interlocks in general
In order to prevent hazardous situations and
maloperation, a series of interlocks are provided
to protect the operators and the switchgear itself.
Note
If the operating mechanism for the three position
switch fail during a switching operation, when
the switch is in an intermediate position, the
electrical interlock between the VD4 X-R circuit-
breaker and the UX2TE-R three position switch
established by the REO 517 is effective. The VD4
X-R circuitbreaker could however be closed
mechanically when the low voltage compartment
door is open.
3.8.2.2 Mechanical interlock (optional)
In addition to the electrical interlock, a mechanical
interlock can be established between the circuit
breaker and the three position switch in a panel.
The interpanel interlock between the circuit
breaker and the three position switches in the
sectionaliser and riser panels is effected in the
riser panel by means of a blocking magnet.
Closing of the circuit breaker is prevented by the
blocking magnet on failure of auxiliary voltage
and when the three position switch is in an
intermediate position. Mechanical opening of
the circuit breaker is always possible when the
low voltage compartment door is open.
Access to the manual operating shaft of the three
position switch is blocked by a flap when the
circuit breaker is closed.
The mechanical interlock is effective even on
failure of auxiliary voltage.
3.9 Earthing a tee-off
3.9.1 Electrical operation using the multifunction
protection and bay control unit REO 517 or
the buttons on the panel front
Operating sequence for tee-off earthing:
•
Circuit breaker (-Q0) OFF
•
Disconnector (-Q1) OFF
•
Earthing switch (-Q5) ON
•
Test for off-circuit condition
•
Circuit breaker (-Q0) ON
•
Secure panel to prevent switching operations
-
Switch off the mcbs for the circuit breaker
and for the operating mechanism of the
three position switch
-
Lock the control cabinet door or secure the
mechanical OFF button for the circuit
breaker if necessary
•
Label the panel to indicate that earthing has
been effected
Cancelling the earthing:
•
Open the control cabinet door and switch on
the mcb release the OFF button for the circuit
breaker if necessary
•
Circuit breaker (-Q0) OFF
•
Earthing switch (-Q5) OFF
15
D E S I G N A N D F U N C T I O N O F T H E S W I T C H G E A R S Y S T E M A N D I T S E Q U I P M E N T
—
Figure 3/1
Panel front view
with multifunction
protection and
switchbay control
unit, measuring
sockets for
capacitive voltage
indicator system at
front (optional),
with pressure relief
duct at top
(optional)
—
Figure 3/2
Panel type ZX1.5-R,
rear view.
Connection of two
cables per line
—
Figure 3/1
—
Figure 3/2
3.9.2 Manual earthing
Follow the same sequence as for electrical
operation, but using the manual push buttons
for the circuit breaker and the crank to operate
the three position switch.
When an additional mechanical interlock between
the circuit breaker and the earthing switch is fitted,
the following actions are necessary:
•
Open the control cabinet door
•
Switch off the circuit breaker (-Q0) by operating
the mechanical push button
•
Open flap (2.22) on the three position switch
operating mechanism (see Interlocks, section
3.8.2b)
Note
Flap (2.22) can only be opened when the circuit
breaker is OFF.
Do not use excessive force!
•
Switch off the disconnector (-Q1) with the
hand crank
•
Switch on the earthing switch (-Q5) manually
using the hand crank (6.1). (Note: Observe
"Emergency manual operation" in section 6.2.2).
about 24 turns clockwise. Close flap (2.22) again
Note
When flap (2.22) is open, the circuit breaker is
blocked in the OFF position.
•
Test for the off-circuit condition (capacitive
voltage indicator system, see section 6.4.1)
•
Switch the circuit breaker (-Q0) on using the
mechanical ON push button
•
Secure the panel to prevent switching operations
-
Switch off the mcbs for the circuit breaker
release circuit and for the operating
mechanism of the three position switch
-
Lock the control cabinet door or secure the
mechanical OFF button for the circuit
breaker if necessary
•
Label the panel to indicate that earthing has
been effected
Cancelling the earthing manually:
•
Open the control cabinet door and switch on the
mcb Release the OFF button for the circuit
breaker if necessary
•
Switch circuit breaker (-Q0) OFF with the
mechanical push button
•
Open flap (2.22)
•
Switch earthing switch (-Q5) OFF manually
•
Close flap (2.22)
3.10 Earthing the busbar
The procedure for earthing the busbar or a busbar
section is dependent on the configuration of
thesystem. Systems with sectionalizers/risers
permit earthing ofa busbar section without
additional equipment.
3.10.1 Electrical earthing of a busbar section
using the sectionalizer/riser
Operating sequence:
•
Circuit breaker in the sectionalizer panel OFF
•
All disconnectors in the busbar section to be
earthed OFF, apart from the disconnector (-Q11
or -Q12) between the busbar section to be
earthed and the sectionalizer breaker
•
Secure the panel to prevent switching operations
-
Switch off the mcbs for the circuit breaker
release circuit and for the operating mechanism
of the three position switch
-
Lock the control cabinet door or secure the
mechanical OFF button for the circuit breaker
if necessary
•
Label the panel to indicate that earthing has
been effected
The busbar section is then earthed. All the panels
in the section concerned are to be secured to
prevent switching operations, e.g. by tripping
the mcbs.
Cancelling the busbar earthing:
•
Open the control cabinet door in the sectionalizer
and switch on the mcb release the OFF button
for the circuit breaker if necessary
•
Circuit breaker (-Q0) OFF
•
Earthing switch (-Q51 or -Q52) OFF
3.10.2 Manual earthing of a busbar section
using the sectionalizer/riser
Perform the switching operations as described
in sections 3.9.2 and 3.10.1 accordingly.
3.10.3 Maintenance earthing of a busbar using
the test sockets in a tee-off
Condition:
•
The tee-off is earthed (see section 3.9)
•
All disconnectors in the busbar to be earthed
are OFF
Operating sequence:
•
Fit a short-circuiting bridge to the test
sockets for the earthed tee-off and connect
to main earthing bar (3.1)
•
Circuit breaker OFF
•
Earthing switch OFF
•
Disconnector ON
•
Circuit breaker ON
•
Secure the panel to prevent switching operations
-
Switch off the mcbs for the circuit breaker
release circuit and for the operating
mechanism of the three position switch
-
Lock the control cabinet door or secure the
OFF button for the circuit breaker if necessary
•
Label the busbar to indicate that earthing
has been effected
The busbar is then earthed. All the panels affected
are to be secured to prevent switching operations,
e.g. by tripping the mcb.
Cancelling the busbar earthing:
•
Open the control cabinet door for the outgoing
feeder and switch the mcb on, if necessary
releasing the OFF switch for the circuit breaker
•
Circuit breaker (-Q0) OFF
•
Disconnector OFF
Cancelling the tee-off earthing:
•
Earthing switch ON
•
Circuit breaker ON
•
Remove the short-circuiting bridge from the test
sockets and seal the sockets with blanking plugs
•
Circuit breaker OFF
•
Earthing switch OFF
3.11 Test facilities
The panels are properly filled with insulating
gas at the works and tested to the VDE or IEC
standards.
Should there be any need to perform tests, the
tests are to be performed as follows:
•
For voltage and current tests, direct access to
the conductors in the connection area is possible
without releasing the cable connection. Access
is effected via the test sockets (1.4)
Surge arresters must be removed during voltage
tests. The empty sockets must be closed with
insulating blanking plugs during testing!
Voltage transformers must be isolated from
the test circuit prior to testing.
•
Voltage tests:
-
Close and insulate free cable sockets with
blanking plugs!
See section 6.4 for further details and the
applicable test voltages.
-
Perform cable tests with DC voltage or with
very low frequency (VLF) cosine or square
wave voltage
-
Cable fault locations measurement with
impulse voltage and
-
Switchgear tests (without cables) with AC
voltage can be performed with a test plug as
shown in figure 6/6 or a test cable
•
A test plug for current tests as shown in figure
(6/7) can be used to test the protection devices
by primary current injection (see also the note
in section 6.4.4). This configuration is short-
circuit proof and can also be used as an
additional maintenance earth
The possible testing processes are described in
the following sections:
•
Testing for the off-circuit
condition: Section 6.4.1
•
Testing for the in-line
condition: Section 6.4.2
•
High voltage tests: Section 6.4.3
•
Maintenance earthing: Section 6.4.4.
Содержание ZX1.5-R
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