GE Industrial Solutions AKD-20 Low Voltage Switchgear - Manuel (Page 50)

AKD-20 Low-voltage Switchgear
Chapter 6. Testing and Inspection
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6-1 General
After the equipment has been installed and all connections made,
it must be tested and inspected before it is put in service.
Although the equipment and devices have been tested at the
factory, a final field test must be made to be sure that the
equipment has been properly installed and that all connections
are correct.
WARNING: The equipment must be completely de-energized
while the tests are in progress.
ADVERTISSEMENT: L’équipement doit être complètement
désamorcé lorsque l’on procède à des tests.
Directions for testing relays, instruments, and meters are given in
the instruction book furnished for each device. The proper
settings of the protective relays and circuit breaker trip units are
normally determined from a complete power system coordination
study performed by the purchaser or their consultant; therefore,
the settings of these devices must be made by the purchaser.
When the equipment is shipped from the factory, the time dial of
all inverse-time induction disc relays (i.e., IFC types) is set to zero to
prevent contact bounce during transportation.
NOTE: The trip setting adjustments of the trip unit for each
circuit breaker may be at any setting when shipped from the
factory and must be correctly set prior to energization of the
equipment.
NOTE: Les ajustements des réglages du disjoncteur peuvent
être en n’importe quelle position lorsque celui-ci est expédié de
l’usine et ils doivent être positionnés correctement avant que
l’équipement ne soit mis sous tension.
General instructions for setting the relays are given in the
applicable Relay or Trip Unit Instruction Book.
The extent of the tests on the equipment as a whole will depend
on the type and function of the equipment. Tests which should be
performed, however, include circuit breaker operation, and
switchgear meggering, phasing, and grounding checks.
High-potential tests to check the integrity of the insulation are not
necessary if the installation instructions are carefully followed. If
local codes demand this test, or the purchaser wishes to make
high-potential tests, the voltage should not exceed 75 percent of
the IEEE factory test voltage.
For the power circuit, the IEEE factory test voltage is two times
switchgear rating plus 1,000 volts. See Table 5-1. Potential and
control power transformers must be disconnected during high-
voltage testing.
Switchgear
Voltage Rating
ANSI
Test Voltage,
ac RMS
Field
Test Voltage,
ac RMS
600V
480V
240V
2200V
1960V
1480V
1650V
1470V
1110V
Table 5-1
6-2 Key Interlocks
After initial installation of the switchgear equipment, all necessary
interlock keys should be inserted into the appropriate locks and all
spare keys should be stored in a location in accordance with the
owner's established procedures.
CAUTION: Refer to the key interlock schematic included in the
summary furnished with the equipment to determine the
sequence of operation and the correct number of operating
keys required. This precaution is necessary since the improper
use of spare keys will defeat the interlocking scheme.
ATTENTION: Référez-vous au schéma des clés de verrouillage
inclus au sommaire fourni avec l’équipement pour déterminer
les séquences d’opération et le nombre correct de clés
d’opération requises. Cette précaution est nécessaire étant
donné qu’un mauvais usage des clés de réserve rendra
inopérant le programme de verrouillage.
6-3 Breaker Operation Test
All compartments housing Entelliguard G circuit breakers have a
TEST position in which the breaker primary contacts are
disconnected while the secondary contacts are still engaged. This
TEST position permits complete testing of the electrical control
circuit without energizing the primary power circuit. When the
breaker is first put into service, its control circuit must be
thoroughly tested while in this position to make sure that all
closing and tripping circuits are complete and functioning
properly.
The TEST position is not suitable for inspection and maintenance
of the breaker and should therefore be used only for testing
breaker operation.
Refer to the appropriate breaker instruction manual for other pre-
operational checks on the breakers. See DEH-41304.
6-4 Entelliguard Trip Units
The calibration of the Entelliguard trip unit should be checked with
the Type GTUTK20 test kit, a portable instrument designed for the
field-testing of Entelliguard trip units. The complete trip system is
comprised of the following components:
1. Solid-state Trip Unit with rating plug
2. Phase Current Sensors
3. Flux Shift Magnetic Trip Device
4. When applicable, a Neutral Sensor for units containing a
Ground Fault Trip element.