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Table of Contents
1. General
2. Insulation Resistance Tests
3. High Potential Tests
4. Protective Relays
5. Short Circuit Rating
6. Potential and Current Transformers
7. Circuit Breakers
8. Busbar
9. Earthing
10. Wiring and Cabling
11. Cable Boxes and Stuffing Glands
12. Battery and Charger
13. Miscellaneous
14. Insulators
15. Shutters
16. Current Carrying Capacity of Rectangular Copper Conductors Temperature Rise 30°C - Air
Temperature 35°C
17. Distance of Busbars and Other Life Parts
18. Meters
19. Accessories
20. Painting
1. General
Before the high voltage switchgear is ready for transport to Namakwa Mine, Relay Settings shall make suitable
tests to establish to the satisfaction of the owner’s engineer that all equipment, devices, protection relays and
wiring have been correctly installed, are in satisfactory working conditions and will operate as intended.
Prior to testing, the switchgear shall be dust-free and thoroughly cleaned of all waste material. Relay Settings will
take care that all the test equipment necessary to do all the tests will be available at the factory and at site.
2. Insulation Resistance Test
2.1. The insulation resistance of each high voltage bus to be measured from phase to phase and from phase
to ground. Insulation resistance test shall be done with a 2500 Volt Megger. Minimum insulation value of
the whole switchboard will be 40 M Ohm.
2.2. Each circuit breaker shall be drawn out of its cubicle, closed manually and the insulation resistance
measured of the primary part from phase-to-phase and from phase-to-ground. Test shall be done with a
2500 Volt Megger. Minimum insulation value will be 50 M Ohm.
2.3. The insulation resistance of all secondary wiring shall be measured from phase-to-ground. Insulation
resistance measuring shall be done with a 500 Volts Megger. Minimum insulation value will be 2 M
Ohm.
3. High Potential Tests
3.1. High potential tests shall be made for the primary side of the switchgear.
3.2. High voltage test for the secondary wiring shall be 2000 Volts for one minute. For motors of switching
mechanism test voltage shall be (2U + 500) Volts.
3.3. Megger test to be carried
4. Protective Relays
4.1 Circuit breaker protective devices shall be secondary relays. 4.2 Each adjustable protective relay shall be set,
calibrated and tested by using a load box, ammeter, voltmeter, variable transformer and any other equipment if
required. Settings, calibration points and test points shall be in accordance with values given in the approved relay
setting curve. 4.3 Each protective relay shall have operating indicators. 4.4 Secondary current type relays, if
withdrawable, shall have provisions for automatically keeping the secondary side of the current transformers
closed when the relay is drawn out. 4.5 Check rotation of directional relays.
5. Short Circuit Rating
Check the indicated short circuit/time rating of the board, breakers, current transformers, fuses, etc. against the
design data.
6. Potential and Current Transformers
6.1 Test all current transformer secondary circuits by applying current to current transformer’s primary side and
verify that relays and/or meters operate properly. 6.2 Test all potential transformer secondary circuits by applying
voltage with the voltage transformers disconnected and verify that relays and/or meters operate properly. 6.3
Check all potential and current transformer’s type, ratio’s, class and output. 6.4 Check that all current transformers
are located in the stationary part of the switchgear. 6.5 Check that potential transformers and their fuses are
mounted in a separate compartment arranged in draw-out construction or equivalent so that the primary
connection will be disconnected before access can be obtained to either the transformer or its primary fuses. 6.6
Check the automatic transfer of service transformers, with the service transformer disconnected. 6.7 Check if
capacity of each service transformer is sufficient to wind the springs of all breakers simultaneously. To avoid
sequential winding of springs set all UV relays in auxiliary motor circuits identically or bypass their contacts.
7. Circuit Breakers
The following tests shall be performed on all circuit breakers: 7.1 In case of low oil circuit breakers the oil level shall
be checked prior to testing the breaker; all breakers shall be carefully checked for oil leakage. 7.2 Trip each circuit
breaker by its mechanical trip devices. 7.3 Trip breaker manually by switch and by applying current and/or voltage
to each of its associated protective relay. 7.4 Inspect the closing mechanism, auxiliary contacts, tripping
mechanisms, etc. 7.5 Check that all circuit breakers or load-break switches of the same ratings are fully
interchangeable also with regard to auxiliary contacts and sequence of auxiliary contacts. 7.6 Check the
mechanical interlock. It shall not be possible to insert or withdraw the breakers when the breaker is in the closed
position. 7.7 Check rapid sequence operation of breakers, starting from closed position of breakers, open-closedopen. (Stored energy). 7.8 Check “the anti pump” device by initiating the closing mechanism with the trip coil
energized. 7.9 Close and trip circuit breaker from its control switch, push-button or operating handle. 7.10 Ensure
satisfactory tripping (electrical and mechanical) of the breakers with the closing coil energized (“free to trip”). 7.11
Moving of the breakers shall not depend on situation of substation floor. 7.12 Contact alignment of each breaker
shall be checked and adjusted where necessary. 7.13 It must be impossible to close the breaker mechanically or
electrically when the breaker is between the test position and plugged in position. 7.14 Take out the circuit breaker
and check if the springs are automatically unloaded if the breaker moves from the test into the completely draw out
position, or, a mechanical interlock to prevent moving of the breaker when springs are loaded. 7.15 Each
mechanical closing button shall have a removable locking device in such a way that it will be impossible to close
the breaker at the switchgear. 7.16 The mechanism of breakers must be suitable for tripping and closing by
continuous remote contacts. 7.17 By-passing of the “breaker closed” lamp may not cause tripping of breaker.
Otherwise resistor shall be adjusted. 7.18 It must be impossible to close the circuit breaker, when the grounding
switch is in the closed position. 7.19 Close a circuit breaker outside the switchboard and bring the breaker in the
test position or fully draw in position. 7.20 Measure the resistance between the fixed contacts of the switchgear
and the removable contacts of the breaker. 7.21 All moving mechanism parts shall be life time lubricated with an
adhesive lubricant. 7.22 All breakers shall have mechanical driven contact position indicator. 7.23 Cubicles shall
be provided with padlocking devices for test and disconnected positions of breakers.
8. Busbar
8.1 Inspect the busbar connections and supports, control busbar and connections. 8.2 Check the busbar size with
busbar rating with an ambient temperature of 35°C and a temperature rise of 30°C. See table, section 16. Busbars
shall be manufactured from copper. 8.3 Check the busbar colors. 8.4 The main earthbar size shall not be less than
25 x 5 mm. Earth bar shall extend throughout the length of the switchgear assembly. 8.5 Check the possibility for
later extension which shall be connected at site. 8.6 Reducing of current capacity of main horizontal busbars is not
acceptable. Section of horizontal copper over switchgear will be of the same size. 8.7 Check sizes of holes in the
busbar system. Reducing of copper section over center line of bolts may not be more than 40% of original copper
section. 8.8 Perform a powerpath continuity test determining the through going resistance of each current carrying
circuit and phase. Testing is done by applying a constant current and measuring the voltage at the current wiring
connection points.
9. Earthing
9.1 Inspect earthing bars and connections inside the board. Inspect the earthing bolts and connections for
equipment earthing. 9.2 Inspect the earth sliding contacts between switchgear structure and breaker. Breaker shall
be grounded by sliding contact all the time that the shutters are not completely closed. 9.3 If a ring current
transformer is used for each fault protection, check that earth connections do not short circuit the primary current
transformer winding. 9.4 Inspect earthing connections to secondary side of current and potential transformers.
Earthing will be direct to current and potential transformers from the earthbar. 9.5 All housing of current and
voltage transformers shall be earthed direct to primary earthing system of the switchgear. 9.6 All doors shall be
earthed by means of a flexible connection. 9.7 Inspect earthing bolts inside the cable boxes.
10. Wiring and Cabling
10.1 Each wire shall be numbered at both ends shall be terminated in a separate terminal. 10.2 Control wiring shall
be at least 1.5 sq.mm. current transformer circuits shall be at least 4 sq.mm. Stranded wiring is required. 10.3 All
cable lugs shall be of the compression type. 10.4 All current transformer circuit terminals shall be provided with
short circuit devices. 10.5 Cable trays or other clamps shall be provided to support all incoming and outgoing
cables. 10.6 Check separation between terminals carrying different voltages. 10.7 Check identification markers on
relays, fuses, switches, terminals etc. which shall be in accordance with certified drawings. 10.8 Check terminals
for outgoing or incoming auxiliary circuits. For example, cables from DC battery to switchgear, cables from LV
switchgear to battery charger etc. 10.9 Wiring of primary circuits between busbars and fuses and wiring of
secondary circuits between potential transformers and the first fuse shall be as short as possible and shall not
touch any metal parts, live parts or other wiring.
11. Cable Boxes and Stuffing Glands
11.1 The HV cable boxes for 3 core cable shall be suitable for the cable as specified and shall be provided with
armor clamps. 11.2 Inspect the quantity, type and size of the stuffing glands and potheads in accordance with the
drawings. 11.3 Inspect the flexible connections between current transformer or busbars to potheads. 11.4 Cable
boxes shall be of the split type. 11.5 Auxiliary cables shall not run through compartments with high tension live
parts. Only exception is breaker compartment when cables are mounted on cable tray.
12. Battery and Charger
12.1 Check battery voltage under normal operating conditions with the trickle charger on and with the quick
charger on. Check also battery voltage with the selector switch on “hand”. 12.2 Check battery voltage under
normal working conditions after disconnecting battery supply for four (4) hours followed by checking of the battery
capacity. 12.3 After restoring battery feeder supply, check the time required to recover to the maximum charging
current. 12.4 Check alarms of battery and battery charger. 12.5 Check ratings of all switches. 12.6 Check the
selectivity between fuses and battery capacity.
13. Miscellaneous
13.1 It shall be impossible to touch live parts with a piece of straight metal wire through holes, gaps etc. 13.2
Inspect the separation of the compartment for secondary wiring and terminals. 13.3 Check framework for mounting
of potheads. 13.4 If link cubicles are concerned check their mechanical lockings. 13.5 Check whether the
switchgear has been provided with splits for shipping sections as per the approved vendor print. 13.6 Inspect
separation of compartments for potheads, breakers, and busbars. 13.7 Check the main dimensions of the
switchgear. Dimensions will be in accordance with the certified drawings (special floor plan drawings). 13.8 Check
nameplates (on front and back of cubicles). Nameplate will be mounted on the fixed part of the switchgear. 13.9
Check doorlocks and keys.
14. Insulators
14.1 All insulators must be free of paint and dust.
15. Shutters
15.1 Shutters shall be completely closed either when the breaker is in the test position or in fully draw out position.
15.2 Shutters will be made of metal and grounded with a copper connection direct to the main ground rail. 15.3
Shutters and shutter mechanism shall be mounted in the breaker compartment and not in the busbar
compartment. 15.4 Shutters shall be painted red for busbars and yellow for circuit or clearly marked “busbar”,
“circuit”.
16. Current Carrying Capacity of Rectangular Copper Conductors
Temperature Rise 30°C - Air Temperature 35°C.
16. Meters
18.1 All meters and relays on front of panel shall be flush mounted. 18.2 Check rating of Volt and Ammeters. 18.3
Check rotation of kWh and kVAh meters.
17. Accessories
19.1 Check breaker truck or fifth wheel. 19.2 Check tools of: · Relays · Contact Gauge · Burnishing Tool · Spring
Setting Tool · Inspection Mirror 19.3 Check manual charging handle. 19.4 Check flexible cables for earthing
purposes. 19.5 Check test jack and plug.
18. Painting
20.1 Color of paint has to be in accordance with specified color in the requisition. 20.2 Vendor shall ensure that
switchgear damaged during transport and erection will be repainted if vendor is doing the erection, otherwise the
vendor will furnish a bottle of paint of the same color of switchgear. 20.3 The color of the shutters to be red for bus
side and yellow for circuit side.
* Optional
Page 2
MTS–2001
INSPECTION AND TEST PROCEDURES (CONTINUED)
Circuit Breakers, Air, Low-Voltage Power
2. Electrical Tests
1. Perform resistance measurements through bolted connections with a lowresistance
ohmmeter, if applicable, in accordance with Section 7.6.1.2.1.
2. Perform insulation-resistance tests on each pole, phase-to-phase and phaseto-ground
with the circuit breaker closed and across each open pole for one minute. Test
voltage shall
be in accordance with manufacturer’s published data or Table 10.1.
3. Perform a contact/pole-resistance test.
*4. Perform insulation-resistance tests on all control wiring with respect to
ground. Applied
potential shall be 500 volts dc for 300 volt rated cable and 1000 volts dc for 600
volt
rated cable. Test duration shall be one minute. For units with solid-state
components, follow
manufacturer’s recommendation.
5. Make adjustments to the trip settings in accordance with the coordination
study.
6. Determine minimum pickup current by primary current injection.
7. Determine long-time delay by primary current injection.
8. Determine short-time pickup and delay by primary current injection.
9. Determine ground-fault pickup and delay by primary current injection.
10. Determine instantaneous pickup value by primary current injection.
*11. Test functions of the trip unit by means of secondary injection.
12. Activate auxiliary protective devices, such as ground-fault or undervoltage trip
devices,
to insure operation of shunt trip devices. Check the operation of electricallyoperated
breakers in their cubicles.
13. Perform minimum pickup voltage test on shunt trip and close coils in
accordance with Table
10.20.
14. Verify correct operation of any auxiliary features such as trip and pickup
indicators, zone
interlocking, electrical close and trip operation, trip-free, antipump function, trip
unit battery
condition, and reset all trip logs and indicators.
15. Verify operation of charging mechanism.
* Optional
Page 3
MTS–2001
INSPECTION AND TEST PROCEDURES (CONTINUED)
Circuit Breakers, Air, Low-Voltage Power
3. Test Values
1. Compare bolted connection resistances to values of similar connections.
2. Bolt-torque levels should be in accordance with Table 10.12 unless otherwise specified
by the
manufacturer.
3. Microhm or millivolt drop values shall not exceed the high levels of the normal range
as indicated
in the manufacturer’s published data. If manufacturer’s data is not available, investigate
any values
which deviate from adjacent poles or similar breakers by more than 50 percent of the
lowest value.
4. Circuit breaker insulation resistance should be in accordance with Table 10.1.
5. Control wiring minimum insulation-resistance values should be comparable to
previously obtained
results but not less than two megohms.
6. Trip characteristics of breakers should fall within manufacturer’s published timecurrent
tolerance
bands.
7. Minimum pickup voltage on shunt trip and close coils should be in accordance with
manufacturer’s
published data. In the absence of manufacturer’s published data, refer to Table10.20.