| Brief
Description of Control Units |
1.
Mains Control Panel
The mains control panel is the control unit of the Cable Test
Van. Through this panel the various test instruments are connected
and receive power for activating the individual instrument. Each
individual test instrument has its own power supply unit that
has to be operated separately. The mains control panel has status
switches that inform the operator on details about the potential
and resistance between Van chassis and ground. The power 'ON'
switch of the mains control panel connot be activated till such
time that all the interlocks are in normal conditions. |
2.
H.V. Selection Switch
The high voltage selection switch alongwith the mains control
panel form the heart of the testing process in a Test Van. The
H.V. selection switch is a two level switch : In level one, the
switch receives power through the mains control panel and in level
two it selects and gets locked to a particular instrument or combination
of instruments selected. Once in operation, any change-over from
the selected position will trip the entire system, discharging
the cable under test & the equipment in operation, thereby
making the op. condition safe. Various interlocks provided will
operate one of the safety loops to disallow a wrong sequence of
operation. |
3.
Safety
Telemetrics gives greatest importance to safety. For us the vital
point in a Cable Test Van is the protection of the operating personnel
from dangerous contact voltages. We strictly follow the norms
of VDE 104. Some of the highlighting safety features are :
Lockable
switch on the operating panel.
Over voltage protection and under voltage protection.
Indication of the operation-switching stage (warning lamps RED
& BLUE).
EMERGENCY-OFF switch mounted at the entrance door.
Door lock switch in HV compartment.
Earth monitoring interlock - F ohm : it does not allow system
to energize if the earth resistance between sub station earth
and operational earth (sheath of the cable under test) exceeds
safe limits.
Chassis voltage monitoring system FU : This interlock operates
in case the van chassis potential elevates more than safe limits.
In such case the monitoring system will trip the complete HV system.
Additionally the monitoring system incorporates an Aux. Earth
Termination, that does not allow the system to energize in unearthed
systems. |
4.
Visual Earth Discharge
The visual earth discharge unit is mounted on a strategic location
in HV compartment. The discharge unit consists of two gold plated
spheres fitted with a time delay circuit. As soon as the H.V.
circuit is switched off or trips, the spheres will drop with a
delay signalling total discharge of all H.V. points and circuits.
The discharge assembly is visible from the operator's cabin as
well as heard while it drops.
Panel mounted instruments that are fixed on to the steel frames.
These can be
* Cable fault prelocation (choose from CAF etc, KABELLUX 3E or
3049).
* Mains operating panel (contains a mains voltage indicator, ON/OFF
switch & status indicator of earth monitoring circuit).
* Voltage stabilizer.
* Arc stabilizing adaptor.
* Hige Pressure Generator (HPG)
Depending upon cable grades, suitable HPG unit is fitted in the
system. It is also capable of
fault pre-location in conjunction with computer aided fault locator
on voltage coupling / decay mode.
* Other Instruments :
Cable Route Tracer System : Choice can be made between 8W - 500W.
Audio Generator depending upon requirement.
Cable Identification System : Portable megger 1KV/5KV, Multimeter.
* Fµ-Fohm unit that will monitor the earth potential and
earth resistance.
* Cables in drums (50m each or as desired of High voltage cable.
Mains cable and earthing cable. |
| |
Movable
Units
These are the instruments which are fixed during transport but can
be pulled out on guide rails during testing.
They are -
* Fault burn down instruments.
* Surge testing and measuring units. |
| |
Other
Facilities
1. The termination of the cable under test is available in the
operators cabin for performing IR test or checking resistances
of the fault or for feeding signal viz audio frequency for route
tracing of cable or for identifying a cable from a bunch.
2. Plug sockets to feed power to any on board equipment say a
personal computer.
3. A Fan and light switch to provide ventilation and illumination
to the operator's compartment.
4. Storage space for storing loose instruments drawings etc.
5. Comfortable seating arrangement for 3 persons.
6. Water cooler & tools box.
7. Each individual instrument can be pulled out of the steel frame
for the purpose of repairs or for carrying out the fault location
activity independent of the vehicle it is mounted on. |
| |
Configuration
Available
* Either on TATA 407 / Tempo Traveller.
* Smaller System mounted on TATA 207 / ARMADA / TEMPO / TRAX / COMMANDER. |
