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Switching Tests for General Purpose switches [1 kV < U < 52 kV]
TEST ORDER: Test Duty 1: 10 close/open mainly active load breaking
Test Duty 2: 10 close/open closed loop breaking current
Test Duty 3: 20 close/open 5% of rated mainly active load
Test Duty 4: 20 close/open cable charging breaking current
Test Duty 5: 2 closings at rated short-circuit current
- no reconditioning of the switch
- recovery voltage must be maintained for at least 0.1 sec after arc extinction
- all tests to be performed on the same switch
IF IN DOUBT OF PERFORMANCE: - Perform temp rise test, with temperatures not to exceed specified values
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Making and Breaking Tests for General Purpose switches [52 kV £ U] IN ANY CONVENIENT TEST ORDER:
100% mainly active load
10 close/open - transmission circuit 10 close/open - parallel transformer ckt
5% mainly active load
at 100% rated current AND at 20-40% rated current
10 for 3-phase test 30 random for single-phase test 12 controlled for single-phase test
Test Duty 4c: busbar charging [only upon agreement between user & manufacturer]
Test Duty 5a: No-load transformer [test not normally required. Number of operations by agreement between user & mfr.]
Test Duty 6: 2 closings at Short-Circuit making
- no reconditioning of the switch
AFTER BREAKING TESTS: - switch must be capable of continuous current with temp. rise not exceeding specified values |
Switching Tests - General [1 kV < U]
TEST ORDER:
THEN, in any order:
20 close/open - Unloaded transformer switching
- Fault-making (no. of operations not specified)
- no maintenance which would affect performance of switch is allowed
Notes: - all tests to be performed on the same switch
- three-phase tests preferred
- capacitor bank switching not part of the above test sequence
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Limited Purpose Test Sequence [1 kV < U < 52 kV] - according to manufacturer's specifications
Increased Operating Frequency Test Sequence - same as above, except using 100 operations for Test Duty 1
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Special-Purpose Switches [52 kV £ U] Test Duties 4d and 4e :capacitor banks 100% rated current AND at 20-40% rated current - number of operations: 10 for 3-phase test 30 random for single-phase test 12 controlled for single-phase test
Test Duty 5b: shunt reactor maximum rated current AND at 20-40% rated current (or minimum, if specified) - number of operations: 10 for 3-phase test 30 random for single-phase test 12 controlled for single-phase test
Test Duty 7a: earth fault current 10 close/open
Test Duty 7b: Cable and line charging under earth fault conditions 10 close/open
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(Switches are tested according to their specified ratings.) |
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Mainly Active Load Switching [1 kV < U < 52 kV] Reference to IEC 56-2 for TRV's
Test Duties 1 & 3: SUPPLY CIRCUIT - power factor not exceeding 0.2 - impedance between 12% and 18% of total impedance of test ckt
LOAD CIRCUIT - power factor between 0.65 and 0.75 - parallel-connected reactors and resistors
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Mainly Active Load Switching [52 kV £ U]
SUPPLY CIRCUIT - power factor not exceeding 0.2 - series-connected reactors & resistors
LOAD CIRCUIT - power factor between 0.65 and 0.75 - parallel-connected reactors and resistors
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Load-Switching current [1 kV < U]
- Table 7 lists specific TRV parameters according to rated max. voltage
LOAD CIRCUIT - power factor between 1.0 and 0.7 lagging - parallel connected load |
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Closed-Loop Breaking Test [1 kV < U < 52 kV]
(Test Duty 2) - power factor not to exceed 0.3
- TRV parameters given in Table IV
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Closed-Loop Breaking Test [52 kV £ U]
Transmission Line - power factor not to exceed 0.3
- open ckt test voltage for three-phase test is 20% for switches rated less than 300 kV, and 15% for switches rated 300 kV and above
- TRV's have triangular wave form
Parallel Transformer - power factor not exceeding 0.2
- TRV's given in Table IVB |
Loop-Switching Current [1 kV < U]
- three-phase: lagging power factor less than 20% - single phase: lagging power factor less than 30%
Line or Cable - TRV parameters given in Table 8, which is based on a 20% recovery voltage
Parallel Transformer - TRV parameters given in Table 9 |
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Cable-Charging Breaking Test [1 kV < U < 52 kV]
(Test Duty 4) - supply side ckt same as mainly active load breaking tests
- capacitive circuit Reference IEC 56-4 |
Cable-Charging Switching Test [52 kV £ U]
(Test Duty 4a) - capacitance of supply circuit as low as possible
- earthing of supply ckt corresponds to conditions in which switch will be used
- for 100 ms after arc extinction, voltage decay not to exceed 10%
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Cable-Charging Switching Test [1 kV < U]- test at rated maximum switch voltage
- leading power factor of less than 20% |
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Line-Charging Switching Test [52 kV £ U] (Test Duty 4b) - capacitance of supply circuit as low as possible
- earthing of supply ckt corresponds to conditions in which switch will be used
- for 100 ms after arc extinction, voltage decay not to exceed 10%
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Line-Charging Switching Test [1 kV < U]
- test at rated maximum switch voltage
- leading power factor of less than 5%
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Busbar Charging Switching Test [52 kV £ U]
(Test Duty 4c)
tests circuits selected by agreement between user and manufacturer
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(No references or tests specified) |
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No-Load Transformer Test [1 kV < U < 52 kV]
- for transformer up to 1250 kVA, no tests specified
- for higher transformer ratings, test is under consideration |
No-load Transformer Test [52 kV £ U]
(Test Duty 5a)
[no specific test methods given] |
Unloaded-Transformer Switching Test [1 kV < U]- for transformer rated 38 kV or less, no tests specified
- for larger transformers, load circuit has lagging power factor between 5% and 10% |
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Shunt-Reactor Test [52 kV £ U]
(Test Duty 5b) - TRV's specified in Table V
SUPPLY CIRCUIT - reactance less than 10% of load reactance - shunt capacitance between 10 and 20 times the load capacitance |
(No references or tests specified) |
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Motor Reference to IEC 470 |
(No reference or tests specified) |
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Earth Fault Switching Test [52 kV £ U]
(Test Duty 7a) - 10 close/open operations
- rated earth fault breaking current
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(No references or tests specified) |
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Single Capacitor Bank Breaking Test [1 kV < U < 52 kV] Reference to IEC 56-4 - 2 closings with rated short-circuit making current must be performed after breaking tests without reconditioning the switch |
Capacitor Banks [52 kV £ U]
(Test Duties 4d and 4e)
- test at 100% and 20-40% of rated capacitor bank breaking current
- back-to-back cap. banks: making current equals rated cap. bank inrush making current
- three-phase test: neutral of cap. bank to be earthed depending on rating or use of switch 10 close/opens
- single-phase test: 30 close/opens for random contact separation OR 12 close/opens for controlled contact separation |
Shunt Capacitor Bank Switching Test [1 kV < U] - same switch used for all following tests:
- capacitive switching current: 100%, 50%, 10%
- total number of operations: 36
- all closings within 15 electrical degrees of a voltage crest
- openings done every 30 electrical degrees ± 15 degrees
- can be tested either single-phase [Figure 10] or three-phase [Figure 11] |
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(No references or tests specified) |
(No references or tests specified) |
Peak Capacitance Inrush Current Test [1 kV < U]
- this is an alternate test to prove making & interrupting ratings
- total number of operations: 36
- preferred test circuit described in Figure 12
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Short-Circuit Making Test [1 kV < U < 52 kV]
- 2 closing operations required
- duration: at least 10 cycles
- at least 100% of rated short-circuit making current in one of the tests, 90% in the other
- if making capacity is not influenced by test duties 1 to 4, then can perform closings on another switch of the same type.
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Short-Circuit Making Test [52 kV £ U] (Test Duty 6) - 2 closing operations
- duration: at least 10 cycles
- at least 100% of rated short-circuit making current in one of the tests, 90% in the other
- switch must have been subjected to at least 10 close/open operations at 100% mainly active load. IF switch performance is not affected by breaking tests, then can use new switch.
- AFTER TEST, switch shall be: - - capable of carrying continuous current. Temperatures must stabilize at 10 K max. above values specified for continuous current tests.
- - capable of interrupting rated currents
- - mechanically operable
- - capable of dielectric requirements
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Fault-Making Current Test [1 kV < U]
- no specified no. of operations
- duration: no less than 10 cycles
- peak current: no less than 2.6 times rated rms symmetrical fault-making current
- three-phase test required where pole-to-pole electromagnetic forces are significant
- conditioning of the switch prior to testing: 10 open/close operations at highest rated current
- AFTER TEST, switch shall be: - - capable of carrying continuous current without thermal runaway
- -if not at end of life, switch must be capable of rated switching duties |