GB 15166.5-1994 Fuses for external protection of AC high voltage fuses and parallel capacitors
Some standard content:
National Standard of the People's Republic of China
AC high-voltage fuses
Fuses for external protection of shunt capacitors
|tt||This standard refers to the International Electrotechnical Commission (IEC) publication 549 "High-voltage fuses for external protection of parallel power capacitors" (1976 edition).
1 Subject content and scope of application
This standard specifies the terminology, ratings, design and structure, test methods, marking, packaging, etc. of fuses for external protection of shunt capacitors (hereinafter referred to as fuses) content and requirements. This standard is applicable to high-voltage fuses that protect a single unit or group (set) of parallel capacitors with a rated voltage of 3 to 35 kV and a frequency of 50 Hz. 2 Reference standards
GB3983.2 High voltage parallel capacitors
GB11022 General technical conditions for high voltage switchgear GB/T15166.1 AC high voltage fuse terminology GB15166.2 AC high voltage fuse current limiting fuse GB15166 .3 AC high-voltage fuse jet fuse GB/T15166.4 AC high-voltage fuse general test method 3 Terminology
The terminology used in this standard is in accordance with GB/T15166.1. 4 Category
The classification of fuses is shown in Table 1.
Table 1
Class
Specification
Protected object
Installation location
5 normal use conditions
Jet type| |tt||Single capacitor
Outdoor
Current-limiting type
Capacitor bank (set)
Indoor
Ambient air temperature is in accordance with GB3983.2 stipulations, and other usage conditions shall be in accordance with the provisions of GB15166.2 or GB15166.3. 6 Rated value
6.1 Rated voltage
The State Bureau of Technical Supervision approved the implementation of com1995-02-01 on 1994-08-12
The rated voltage and the highest voltage are selected according to Table 2. Rated voltage
Maximum voltage
6.2 Rated insulation level
3
3.6
6
7. 2
GB15166 .5—94
Table 2
10
12
15
17.5
According to GB11022, there is no phase-to-phase and ground insulation The required fuses are only subjected to the fracture withstand voltage test. 6.3 Rated current
6.3.1 The rated current of the fuse is selected from the following values: 12.5,20,25,31.5,50,80,100,200A20
24
kv
35
40.5
6.3.2 The rated current of the fuse is determined by negotiation between the user and the manufacturer. For fuses used to protect a single parallel capacitor, it is recommended to select them according to the principles in Appendix A.
6.4 The rated capacitive and inductive breaking current of the fuse should be selected from Table 3. The breaking discharge energy is specified by the manufacturer. Table 3
Rated capacitive breaking current (effective value), A rated inductive breaking current (effective value), kA design and structural requirements
7.1 Resistance value of fuse or fuse piece||tt ||The priority value is 20 times or 50 times the rated current of the fuse, and other values ??are determined by the manufacturer and the user through negotiation
3.15, 6.3, 8, 12.5, 16, 25, 31.5, 40 fuses or fuses The resistance value and its error should comply with the manufacturer's specifications. 7.2 Pre-arc time-current characteristics
7.2.1 The fuse should have stable pre-arc time-current characteristics. Characteristic curve and its tolerance range: current-limiting fuses should comply with the provisions of GB15166.2, and spray-type fuses should comply with the provisions of GB15166.3. 7.2.2 Limits of pre-arc time-current characteristics 7.2.2.1 For overload protection For fuses used to protect a single parallel capacitor, the pre-arc time-current characteristic deviation should not exceed the tolerance, and the corresponding points should not exceed the limits specified in Table 4. It is recommended that the rated non-melting current of the fuse is 1.1 times Current, under this current, the fuse should ensure that it does not blow out for 4 hours. Table 4
Rated current multiple of fuse
Melting time, 8
1.5
Not more than 75
2.0
Not more than 7.5| |tt||7.2.2.2 For fuses used to protect a single parallel capacitor without overload protection characteristics, the limit of pre-arc time-current characteristics is not specified. 7.3 Temperature rise
The maximum allowable temperature and allowable temperature rise of the parts, materials and media of the fuse are in accordance with the provisions of GB15166.2 or GB15166.3. When the ambient air temperature is in accordance with the provisions of GB3983.2, the maximum allowable temperature The temperature remains unchanged, and the allowable temperature rise is calculated according to the corresponding ambient air temperature. 7.4. Breaking performance
The fuse should break capacitive, inductive current and discharge energy under rated parameters and in accordance with specified procedures and requirements. Fuses used in different occasions should have the breaking performance required in Table 5. Inductive breaking
Test
Performance
Performance
GB15166.5--94
Table 5
Group (set) protection fuse
Fuses are used where inductive current
is likely to flow"
Fuses are used where inductive current is unlikely to flow"
Capacitive breaking test
Discharge breaking test
Note: 1) Examples of this application are,
capacitor bank (set) fuse
without series connection A single fuse in a delta-connected group of units3)
V
A single fuse in a star-connected group without grounded neutral point of units in series2) For this application Examples are:
A single fuse in a star connection group with an ungrounded neutral point and a capacitor bank with a coupling unit
3) A star connection group (set) with an ungrounded neutral point ) Protective fuses must undergo a capacitive breaking test. 7.5 Withstand discharge performance
Single protection fuse
v
V
>
The fuse should be able to withstand the first An inrush current impact with a half-wave amplitude not less than 70 times the rated current of the fuse. 7.6 Anti-corrosion layer
All exposed metal parts of the fuse should have reliable anti-corrosion measures, and their surfaces should be smooth and clean. 7.7 Indicating device
The fuse should have obvious fusing indication and should operate reliably. 7.8 The main matching dimensions and installation dimensions of the same series should be unified and interchangeable. 7.9 The fuse piece of the jet fuse should be provided by the manufacturer or equipped with the specified fuse piece. 8 Test Methods
8.1 Appearance and Dimensions Inspection
The appearance and dimensions should comply with the requirements of technical documents and drawings. 8.2 Resistance measurement
shall be carried out in accordance with Article 9 of GB/T15166.4. 8.3 Insulation test
shall be carried out in accordance with Article 6 of GB/T15166.4. 8.4 Temperature rise test
shall be carried out in accordance with Article 7 of GB/T15166.4. 8.5 Withstand discharge test
The discharge withstand test includes the following two tests: discharge the same fuse 5 times within 10 minutes, and the discharge oscillation frequency is: a.
i) For rated current not greater than The 31.5A fuse is: f(kHz)=1.2U.+2%
i) The fuse with the rated current greater than 31.5A is: f(kHz)=0. 8U.+2%|| tt||In the formula: U.—the highest voltage, measured in kV. When the same fuse is discharged 100 times at the time interval specified by the manufacturer, the discharge oscillation frequency is 8+2°%kHz. h. | | tt | The ratio of adjacent peak values ??of discharge current is 0.8 to 0.95. The metal short-circuit test should replace the fuse under test with a connecting conductor with negligible impedance compared with the test circuit. Adjust the loop to obtain the specified first half-wave current multiple, oscillation frequency and attenuation. This should be checked with an oscillogram. The fuse shall still be conductive after the test.
8.6 Breaking test
8.6.1 Inductive current breaking test
The inductive current breaking test is carried out according to test method 1 and method 2 of GB15166.2 Article 8.7.4 for current-limiting fuses, and according to GB15166.3 Article 2 for spray-type fuses. 7.6.3 Test methods 1 to 3 are carried out. 8.6.2 Capacitive current breaking test
The capacitive current breaking test includes the small capacitive current breaking test and the rated capacitive current breaking test. The test is carried out on a single fuse and the fuse with the maximum rated current value is selected for the same series of fuses. The installation method of spray-type and current-limiting fuses that automatically generates insulation distance after operation shall comply with the design requirements. An energized fuse identical to the one under test should be placed on both sides of the fuse under test to determine whether the ejected gas will cause flashover, which may cause adjacent fuses to operate (see note). Other limitations Flow fuses can be installed in any convenient manner. Note: When the test conditions are not met, energized fuses do not need to be placed on both sides of the test sample. The test parameters are shown in Table 6, the small capacitive current breaking test circuit is shown in Figure 1, and the rated capacitive current breaking test circuit is shown in Figure 2. Table 6
Parameters
Power frequency recovery voltage
Power factor (lead)
Expected current
Connection angle after voltage crosses zero||tt ||Number of tests
Number
Test
Small capacitive current breaking
1.5 times the rated current
Any
31| |tt||Note: 1) For jet fuses, the specified number of breaking tests should be carried out on the same fuse-carrying part. Figure 1 Small capacitive current breaking test circuit
Test item
U.+%
0.15
Item
Rated capacitive current breaking| |tt||Rated capacitive breaking current
0～20°
3)
C
Figure 2 Rated capacitive current breaking test circuit||tt ||G - generator, E, power supply voltage; E - recovery voltage, F - fuse, S - switch; C, a capacitor that generates test current, C, a capacitor equivalent to a parallel connection with the fault capacitor, C, not Less than 300kvarGB15166.5-94
The impedance of the power circuit should be such that the voltage change caused by switching capacitive current does not exceed 10%, the power factor should not exceed 0.15 (lag), and the capacitance to ground should be as low as possible .
During the metal short-circuit test, the fuse under test uses a connecting conductor with negligible impedance instead to adjust the expected current. The voltage E, E reaches the specified power frequency recovery voltage. This should be verified by an oscilloscope. The waveform of the breaking current should be as close to the sinusoidal waveform as possible. The ratio of the effective value of the current to the effective value of the fundamental component does not exceed 1.2, which is considered to meet the conditions.
The breaking current should not cross zero more than once every half cycle. The conditions for qualifying the test are:
No flashover to ground or adjacent capacitors occurs during the breaking process, nor does it cause the action of adjacent fuses. The flame or dust ejected when the current-limiting fuse operates The degree is in accordance with the requirements of GB15166.2. Heavy breakdown must not occur during the breaking process, which can be judged by the oscilloscope. After each operation, only the reinstallation unit is allowed to be replaced according to regulations. Other parts should be kept in good condition and must not be repaired or replaced. After the fuse operates, it should be able to withstand the DC voltage component caused by the power frequency recovery voltage plus the residual charge on the capacitor. The power frequency recovery voltage holding time: 1s for fuses that automatically generate isolation gaps after operation, and for other current-limiting fuses. Type fuse is 60s. 8.6.3 Discharge breaking test
Among the same series of fuses, the fuse with the maximum rated current value is selected for the current-limiting fuse; the fuse with the maximum arcing distance is selected for the injection fuse. If there are several fuses with the same arcing distance, select the fuse with the smallest rated current value (see Figure 3 for the test wiring diagram).
o
Figure 3 Discharge breaking test wiring diagram
White.
D rectifier; F - fuse under test R - current limiting resistor, K - ignition ball gap, C - capacitor; O1 - voltage measurement G power supply; O: current measurement; S - switch
The capacitors used in the test shall be charged with DC to the following voltage values. For current limiting fuses it is 1.822U.
For jet fuses it is 1.102U.
The capacitance of the capacitor should be such that the stored energy has a specified value at the above voltage. The capacitor is discharged through the fuse under test, and the oscillation frequency of the circuit should be the same as the test specified in item a of 8.5. The ratio of adjacent peak values ??of discharge current is 0.8 to 0.95. The metal short-circuit test should replace the fuse under test with a connecting conductor with negligible impedance. The loop is adjusted to obtain the specified discharge energy, oscillation frequency and attenuation, which should be verified with an oscillogram. After the fuse operates, for fuses without obvious air gaps, the voltage should be retained at both ends of the fuse for 10 minutes (this requires that the capacitor used for testing has no discharge resistor). For other fuses, the voltage is not required to be maintained. GB15166.5-94
For current-limiting fuses, the residual voltage on the capacitor should be measured immediately after discharge to determine the energy consumed on the fuse. This residual voltage should be recorded in the test report.
The conditions for passing the test are during and after the fuse is broken. Current-limiting fuses should comply with the regulations of GB15166.2, and spray-type fuses should comply with the regulations of GB15166.3. 8.7 Pre-arc time-current characteristics test
The pre-arc time-current characteristics test shall be carried out in accordance with Article 7.2.2 and GB/T15166.4. 9 Inspection rules
Product inspection is divided into type test and factory inspection. 9.1 Type test
Type test is a test to verify whether the product meets the standards. The test specimens for type testing shall be consistent with the product technical documents and drawings and shall pass the factory inspection.
9.1.1 The fuse shall be type tested under the following circumstances. a.
Trial new products,
b.
Products transferred to factory production;
c.
When the design, process or use of the product When there are changes in materials that may affect the performance of the product d.
When products that are not frequently produced are produced again; for frequently produced products, a temperature rise test and a small capacitive current breaking test should be conducted every 8 to 10 years And pre-arc time-current characteristic test of fuses with maximum and minimum rated e.
constant current values. 9.1.2 Type test items
a.
b.
c.
d.
e.
Appearance and dimensions Inspection:
Resistance measurement of fuse or fuse piece;
Insulation test,
Temperature rise test;
Withstand discharge test;
f.| |tt|| Breaking tests include: inductive current breaking, capacitive current breaking, discharge current breaking; g.
pre-arc time-current characteristic test.
9.2 Factory inspection
The factory inspection items are as follows:
a.
b.
Appearance and dimensions inspection:
Fuse Or fuse resistance measurement:
power frequency 1min withstand voltage test (only for products with phase-to-ground insulation); c.
pre-arc time-current characteristic test. | |tt | For 3 units, products with overload protection characteristics should comply with the requirements of Article 7.2.2.1, and the inspection content of other fuses should comply with factory requirements. All tests should be qualified. If one unit fails, the spot check should be doubled. If there is still one unit that fails, the batch of products will be judged to be unqualified. 10 Marks and Packaging
10.1 Mark
The following content must be firmly and clearly marked on the fuse and fuse-link: 10.1.1 Fuse
Manufacturer's name or trademark;|| tt||a.
b． Fuse model or code;
rated voltage, kV:
c.
d. Rated current, A,
e. Manufacturing date or batch number.
10.1.2 Fuse
a The fuse model or code used,
b. Rated current, A.
10.2 Packaging
GB15166.5-94
The packaging of the fuse should ensure that it is not damaged, deformed and damp during transportation. The outside of the packaging box should be protected during transportation and storage. Obvious signs that must be paid attention to (such as upward, rain-proof, moisture-proof, shock-proof, etc.). The packaging box should contain random documents such as certificates of conformity, packing lists and instructions for use, as well as specified accessories and spare parts. The instructions for use and accompanying documents should include the following: a.
b.
c.
d.
e.
f.
g.
fuse The percentage of cold resistance and resistance tolerance: discharge resistance performance (the first half-wave amplitude of the discharge current is a multiple of the rated current of the fuse); discharge current breaking performance (the maximum energy that can withstand without bursting) , rated inductive breaking current;
rated capacitive breaking current;
insulation level,
pre-arc time-current characteristics and current allowable when the ambient air temperature is 20℃ The difference in percentage. GB15166.5-94
Appendix A
Principles for selecting fuses for single capacitor protection (reference parts)
The rated current of the fuse selected for A1 fuse is generally 1.43 times the rated current of the protected capacitor. Note: Usually the capacitor should be able to operate continuously at 1.3 times the rated current. Considering that the capacitance of the capacitor is allowed to reach 1.1 times the rated capacitance, the maximum allowable current in the capacitor can reach:
1.3 ×1.1=1.43 times rated current
The pre-arc time-current characteristic of A2 fuse should be below the 10% burst probability curve of the protected capacitor shell. The matching principles of the curves shown in Figure A1 are available for reference.
The number of A3 parallel capacitor banks connected in parallel should be determined based on the discharge current breaking parameters of the fuse. A4 In a capacitor bank with series units, the rated voltage, insulation level and breaking parameters of a single parallel capacitor protection fuse should be adapted to the operating conditions. | |tt | |Water Yao is broken
Loss of oil
10%
Second zonebZxz.net
Severe external charge
Damage of oil injection
50%
Danger zone
Severe acid damage to the casing
Damage nearby items
90%
Capacitor
Current, A||tt| |Figure A1 The burst probability curve of the capacitor shell and the fuse pre-arc time-current characteristic curve are combined with additional instructions:
This standard is proposed by the Ministry of Mechanical and Electronics Industry of the People's Republic of China. This standard is under the jurisdiction of the National Switchgear Standardization Technical Committee. This standard is drafted by Xi'an High Voltage Electrical Equipment Research Institute. The main drafters of this standard are Hou Zhongji, Teng Junqing, Xu Guozheng and Li Peng.
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