Some standard content:
ICS31.060.70
Standard of the Machinery Industry of the People's Republic of China
JB 7112-2000
Assembly type high voltage shunt capacitor
High voltage shunt capacitor of the assembling type2000-04-24 Issued
National Bureau of Machinery Industry
2000-10-01 Implementation
JB7112-2000
This standard is a revision of JB7112-93 "Assembly type shunt capacitor". This standard is consistent with relevant standards. Compared with JB7112-93, the main technical content of this standard has the following changes: The name of the standard is changed to "Assembly type high voltage shunt capacitor". 2 The provisions that when conducting the inter-electrode withstand voltage test, if limited by the test equipment, the capacitor unit, discharge device, insulation support, etc. can also be tested separately have been deleted.
3 The provisions that if the test conditions are limited, the capacitance can be measured at a voltage lower than the rated voltage after obtaining the consent of the purchaser during the capacitance and loss tangent measurement are deleted; or the capacitance of the internal capacitor unit can be measured only. 4 The provisions that if the test conditions are limited, the test can be conducted at the rated voltage after consultation with the purchaser during the temperature rise test are deleted. 5 The test of the internal capacitor unit and the mechanical strength test of the bushing are added to the test method, and the test requirements of the capacitor unit inside the collective parallel capacitor are clarified. The test voltage is adjusted according to GB311.1-1997 "Insulation Coordination of High-voltage Transmission and Transformation Equipment". 6
The provisions on "warning sign", "chemical conditions" and "mechanical conditions" are deleted, and necessary modifications and supplements are made to the terms "rated voltage", "voltage level" and "insulation level". 8
This standard replaces JB7112-93 from the date of implementation. Appendix A of this standard is the standard appendix; Appendix B is the prompt appendix. This standard is proposed and managed by the National Technical Committee for Standardization of Power Capacitors. This standard was drafted by: Xi'an Power Capacitor Research Institute, Wuxi Power Capacitor Factory. The main drafters of this standard are: Shen Wenqi, Yang Yimin. This standard was first issued in October 1993. This standard is entrusted to the National Power Capacitor Standardization Technical Committee for interpretation. I
1 Scope
Machinery Industry Standard of the People's Republic of China
Assembly type high voltage shunt capacitor
High voltage shunt capacitor of the assembling typeJB7112-2000
Replaces JB7112-93
This standard specifies the scope, definition, classification, technical requirements, test methods, inspection rules, marking, packaging, lifting, transportation and storage, safety requirements, etc. of assembled high voltage shunt capacitors. This standard applies to assembled high voltage shunt capacitors filled with insulating oil (hereinafter referred to as "capacitors") connected in parallel in AC power systems with a frequency of 50Hz or 60Hz and a rated voltage higher than 1kV to improve the power factor. 2
Cited Standards
The clauses contained in the following standards constitute the clauses of this standard through reference in this standard. At the time of publication of the standard, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T16927.1—1997 High Voltage Test Technology Part 1: General Test Requirements (eqvIEC60060—1:1989) GB50227—1995
JB/T5347—1999
3 Definitions
This standard adopts the following definitions.
Design Specifications for Shunt Capacitor Devices
Flake Heat Sink for Transformer
3.1 Internal Capacitor Unit (Internal Unit) internalcapacitorunitinternalunit) An assembly of one or more capacitor elements assembled in a single housing and having lead terminals inside a collective capacitor. 3.2 Capacitor of the assembly type A capacitor consisting of an appropriate number of internal capacitor units assembled in a large box filled with insulating medium. 3.3 Rated voltage (U%)
ratedvoltage (UN)
The root mean square value of the AC voltage specified when designing the capacitor. 3.4 Rated capacitance (Cn) ratedcapacitance (Cn) The capacitance value calculated from the rated capacity, rated voltage and rated frequency of the capacitor. 3.5 Rated current (IN)
rated current (I)
The root mean square value of the AC current specified when designing the capacitor. 3.6 Rated frequency (fn) ratedfrequency (fn) The frequency specified when designing the capacitor.
3.7 Rated capacity (Q%) ratedoutput (Qn) The reactive power specified when designing the capacitor. 3.8 Loss loss
Approved by the State Bureau of Machinery Industry on April 24, 2000, implemented on October 1, 2000bZxz.net
The active power consumed in the capacitor.
JB7112-2000
Note: The loss of the capacitor should include the loss of all components inside the capacitor. The loss angle tangent (tan5)
tangentofthelossangle(tan)
The ratio of the loss of the capacitor to the reactive power under the specified sinusoidal AC voltage and frequency. 3.10 Maximum allowable voltage maximum permissible voltage The maximum AC voltage (RMS value) that the capacitor can withstand for a specified time under specified conditions. 3.11 Maximum allowable current maximum permissible current The maximum AC current (RMS value) that the capacitor can withstand for a specified time under specified conditions. 3.12 Residual voltage residual voltage
The voltage remaining between the terminals of the capacitor after it has been disconnected from the power supply for a certain period of time. 3.13 Internal fuse internal fuse
A fuse connected in series with an element or group of elements in an internal capacitor unit. 3.14 Steady-state condition The thermal equilibrium state reached by the capacitor at a constant output and constant ambient air temperature. 3.15 Ambient air temperature ambient air temperature The air temperature where the capacitor is to be installed. 3.16 Cooling air temperature cooling air temperature The temperature measured at 0.1m from the capacitor casing and 2/3 of the height from the bottom under steady-state conditions. 3.17 Line terminal lineterminal
A terminal used to connect to the power line. Note: In a multi-phase capacitor, the terminal intended to be connected to the neutral line is not called a line cat. 3.18 Auxiliary circuit terminal terminal for the auxiliary circuit A low-voltage terminal on the capacitor used to output voltage and/or current signals for relay protection and measurement. 3.19 Discharge device discharge device
A device installed in an internal capacitor unit or connected across the line terminals of a collective high-voltage shunt capacitor. When the capacitor is disconnected from the power supply, it can reduce the residual voltage on the capacitor to below the specified value within a specified time. 4 Classification
4.1 Ambient air temperature category
The ambient air temperature range of the installation and operation area is: -50℃～+55℃. Within this temperature range, it is divided into several temperature categories according to the ambient air temperature range that the capacitor can adapt to. Each temperature category is represented by a letter code of the lower limit temperature value and the upper limit temperature separated by a slash.
The lower limit temperature is the lowest ambient air temperature at which the capacitor can be put into operation, and its value is selected from +5℃, -5℃, -25℃, -40℃, and -50℃.
The upper limit temperature is the highest ambient air temperature at which the capacitor can operate continuously. The upper limit of the ambient air temperature corresponding to the letter code is shown in Table 1.
Any combination of the lower limit temperature and the upper limit temperature can be selected as the standard temperature category of the capacitor. The preferred standard temperature categories are: 2
40/A, 25/B,
5/A and -5/C.
JB7112-2000
The upper limit of ambient air temperature corresponding to the letter code, code
Note: The temperature values in the table can be obtained from meteorological data4.2 Rated voltage
The priority values of rated voltage are as follows:
Ambient air temperature ℃
24h average maximum
Annual average maximum
3.15, 6.6/V3, 6.6, 11//3, 11, 12//3, 12, 22/V3, 22, 38.5//3, 38.5, 69.3//3kv
4.3 Rated capacity
The priority values of rated capacity are as follows:
Single phase: 1667, 2500, 3334, 5000, 6667, 10000kvar. Three-phase: 1000, 1200, 1500, 1800, 2400, 3000, 3600, 4200, 5000, 7500, 10000, 15000, 20000 kvar.
Note: Capacitors with other ratings can be manufactured according to the needs of the purchaser. 5 Technical requirements
5.1 Usage requirements
5.1.1 Altitude
The altitude of the installation and operation area shall not exceed 1000m. Note: The requirements for capacitors used in areas with an altitude higher than 1000m shall be determined by negotiation between the purchaser and the manufacturer. 5.1.2 Ambient air temperature
Should comply with the temperature category corresponding to the capacitor. 5.1.3 Residual voltage when put into operation
When the capacitor is put into operation, the residual voltage on its terminals shall not exceed 10% of the rated voltage. 5.1.4 Overload
5.1.4.1 Steady-state overvoltage
The continuous operating voltage of the capacitor is 1.00U, and it can operate for a corresponding time under the steady-state overvoltage specified in Table 2. The overvoltage value that can be tolerated by the capacitor without significant damage depends on the duration, the total number of times and the temperature of the capacitor. The overvoltage higher than 1.15U% in Table 2 is determined on the premise that it occurs no more than 200 times in total during the life of the capacitor. 5.1.4.2 Operation overvoltage and overcurrent
When switching capacitors with switches without heavy breakdown and bounce, a transient overvoltage with a peak value of no more than 2√2 times the applied voltage (root mean square value) and a duration of no more than 1/2 cycle may occur. The peak value of the corresponding transient overcurrent may reach 100IN. In this case, 1000 operations per year are allowed. When the capacitor needs to be operated more frequently, the steady-state overvoltage value and duration and the transition overcurrent 3
JB7112-2000
should be limited to a lower level, and the limit value shall be determined by negotiation between the purchaser and the manufacturer. Table 2 Steady-state overvoltage
Power frequency plus harmonics
5.1.4.3 Steady-state overcurrent
Voltage factor XUN
(Root mean square value)
Maximum duration
The highest average value during any period of capacitor operation. Continuous
8h in every 24h
30min in every 24h
So that the current does not exceed the value given in 5.1.6.3. Exceptions occurring during operation for less than 24h are as follows:
System voltage regulation and fluctuations
System voltage regulation and fluctuations
Voltage rise at light load
Capacitors shall be suitable for continuous operation with an RMS value not exceeding 1.30 times the current produced by the capacitor at rated frequency, rated sinusoidal voltage and without transient conditions. Since the actual capacitance may be 1.10C, this overcurrent may reach about 1.43IN. This overcurrent is the result of the combined effect of harmonics and overvoltages up to 1.10UN. 5.1.4.4 Maximum allowable capacity
Taking into account the steady-state overvoltage, steady-state overcurrent and positive capacitance deviation, the total capacity of the capacitor shall not exceed 1.35Qn5.1.4.5 Power frequency plus harmonic overvoltage
The power frequency plus harmonic overvoltage during capacitor operation shall not cause the overcurrent to exceed the specified value in 5.1.4.3. If the capacitor is operated at no more than 1.10U, the voltage peak including all harmonic components shall not exceed 1.2V2UN. Note: When the capacitor needs to be installed in an environment that does not comply with the provisions of this article, the purchaser shall negotiate with the manufacturer. 5.2 Performance and structural requirements
5.2.1 Discharge device
If the discharge device of the capacitor is a discharge coil, the discharge coil shall be able to reduce the residual voltage on the capacitor from √2U to below 50V within 5s. If it is a discharge resistor, it shall be able to reduce from /2U% to below 75V within 10min. The discharge coil or discharge resistor used shall comply with the provisions of the corresponding standards or technical conditions. Note: According to the needs of the purchaser, a discharge device that can drop to a lower voltage in a shorter time can be installed. 5.2.2 Internal capacitor unit
In addition to complying with the requirements of the current standard "Parallel capacitors for AC power systems with nominal voltages above 1kV", the internal capacitor unit shall also meet the following requirements:
The thermal stability test of the internal capacitor unit shall be carried out in accordance with the method of 6.11.1. The discharge test and partial discharge test shall be carried out one by one: the partial discharge test and inter-electrode electrical strength test of the internal capacitor unit can be carried out simultaneously in accordance with the test method of 6.11.2: The internal fuse test is carried out according to the maximum energy allowed for parallel connection. The bushing creepage distance is considered to be used in oil, the outer shell should not rust, and if there is a protective coating, it should not affect the performance of the insulating oil.
5.2.3 Safety protection device
The capacitor should be equipped with an explosion-proof device (such as a pressure release device) that can operate reliably when the internal pressure of the oil tank exceeds 0.05MPa positive pressure. 4
According to the purchaser's requirements, a gas relay can be installed. 5.2.4 Oil compensation device
JB7112-2000
5.2.4.1 Capacitors with non-sealed structures should be equipped with oil storage tanks, and their volume should be able to ensure that the oil does not overflow when the capacity reaches 1.35Qn at the upper limit temperature. One end of the oil storage tank should be equipped with an oil level gauge, and it should indicate three oil level marks when the capacitor is not put into operation, which are equivalent to temperatures of -30℃, +20℃, and +40℃. When the capacitor is not put into operation at the lower limit temperature, oil can be seen on the oil level gauge. The oil storage tank should have oil filling, oil discharge and oil drainage devices. Except for products with ammonia protection, desiccant with oil seals should be installed. 5.2.4.2 Capacitors with sealed structures should be equipped with expanders, which should ensure that when the capacity reaches 1.350% at the upper limit temperature, the oil pressure does not exceed the upper limit of the allowable working pressure of the expander: when the capacitor is not put into operation at the lower limit temperature, the oil pressure does not appear negative. 5.2.5 Oil temperature measuring device
Signal thermometers can be installed to measure oil temperature according to user requirements. The installation position of the thermometer should be convenient for observation. The tube seat of the thermometer should be located at the top of the oil tank and extend into the oil (120±10) mm. The signal contact capacity should not be less than 50VA at AC voltage 220V; not less than 15W at DC inductive load. The accuracy of the thermometer should not be less than Class 2.5. 5.2.6 Oil tank and its accessories
5.2.6.1 An oil sample valve and an oil drain device should be installed on the lower wall of the oil tank. 5.2.6.2 The oil tank should have sufficient mechanical strength and can meet the requirements of no obvious deformation in normal lifting and transportation. 5.2.6.3 The installation position and mutual distance of the bushings should be convenient for wiring, and the air gap of its live parts should comply with the relevant standards. 5.2.6.4 The structure of the oil tank and its accessories should be easy to disassemble, install and replace. 5.2.6.5 The case, bracket and oil tank of the capacitor unit should have reliable electrical connections, and the oil tank should have connecting bolts no smaller than M16. 5.2.7 Radiator
If the capacitor is equipped with a plate radiator, it should comply with the requirements of JB/T5347. 5.2.8 Insulating oil
Before the insulating oil for the capacitor is placed in the oil tank, its various properties should comply with the provisions of the corresponding standards; the withstand voltage value of the oil sample taken from the bottom of the oil tank should be no less than 45kV.
5.2.9 Sealing performance
The sealing performance of the capacitor should be sufficient to ensure that it will not leak for at least 2 hours after all parts have reached the maximum allowable operating temperature of the dielectric.
5.2.10 Appearance and anti-corrosion layer
The appearance of the capacitor should comply with the drawings and technical requirements, and its exposed metal parts should have a good anti-corrosion layer. 5.2.11 Capacitance Deviation
The deviation between the capacitance measured in accordance with 6.4 and its rated value shall not exceed 0~+10%. The ratio of the maximum value to the minimum value of the capacitance between any two line terminals of a three-phase capacitor shall not exceed 1.06 (for type III outlets, it shall not exceed 1.06 when connected in Y shape, and shall not exceed 1.10 when measuring each single phase). Note: A smaller capacitance deviation may be specified upon consultation based on user needs. 5.2.12 Loss Tangent (tanS)
Capacitors are used for 6.7 The loss tangent of the test method specified in 20℃ should not exceed that specified in Table 3. 5
Dielectric structure
Film-paper composite
JB7112-2000
Table 3 Loss tangent
Without internal fuse
Note: The above loss tangent does not include the loss of the internal discharge coil 5.2.13
Electrical strength between poles
Loss tangent
With internal fuse
The capacitor poles must be able to withstand one of the following two test voltages for 10s. The type of voltage used is selected by the manufacturer (AC voltage is preferred):
a) Power frequency AC voltage: 2.15Un;
b) DC voltage: 4.3UN.
Note: For multi-phase capacitors, the test voltage should be adjusted so that each phase can be subjected to the specified voltage. 5.2.14 Insulation level
The insulation between all line terminals of the capacitor insulated from the tank and the tank and between the phases of the internal III-type connected capacitors shall be able to withstand the withstand voltages listed in Table 4. The short-time power frequency withstand voltage is applied for 1 min. The insulation between the auxiliary circuit terminals of the capacitor and the tank shall be able to withstand the 3kV power frequency test voltage for 1 min. Table 4 Insulation level
Insulation level of capacitors
Short-time power frequency withstand voltage
Root mean square value
Lightning impulse withstand voltage
(1.2~5)/50μs peak value
Note: For the same equipment with two insulation levels for the highest voltage, the selection should take into account the grid structure and overvoltage level, the configuration and performance of the overvoltage protection device, the acceptable insulation failure rate, etc. The data under the slash is the dry withstand voltage of the external insulation. The corresponding insulation level of the capacitor rated voltage is shown in Table 5. Table 5 Insulation level
Capacitor
Rated voltage
Insulation level
11/ V3
5.2.15 Short-circuit discharge tolerance
JB71122000
Capacitors must be able to withstand short-circuit discharge caused by external faults at the permitted operating voltage. 5.2.16 Temperature rise
After the test in 6.8, the temperature rise of the upper oil layer of the capacitor should not exceed 15K. 5.2.17 Mechanical strength of the casing
Should be able to withstand a horizontal tensile force of 980N.
6 Test method
6.1 Test conditions
All tests and measurements of capacitors, unless otherwise specified, should be carried out under the following conditions: a) The ambient air temperature is 5℃~35℃. If correction is required, the value at 20℃ shall prevail. The temperature of the capacitor should not be significantly different from the ambient air temperature. If the capacitor has been placed in a constant ambient air temperature for a suitable period of time without power, the dielectric temperature of the capacitor can be considered to be the same as the ambient temperature: b) The waveform of the AC voltage used for testing and measurement should be a true sine wave (see GB/T16927.1). Regardless of the rated frequency of the capacitor, AC testing and measurement can be carried out at 50Hz or 60Hz. 6.2 Inspection of appearance and supporting components
Inspect according to the requirements of 5.2.2~5.2.7 and 5.2.10. The appearance inspection is carried out by visual inspection and measuring tools.
Inspection of supporting components mainly inspects whether the internal capacitor unit has been tested according to the requirements of 5.2.2. Whether other supporting components have certificates of conformity and whether their main technical conditions meet the requirements of this standard and relevant standards, 6.3 Sealing test
The capacitor should be subjected to a test that can effectively detect any leakage on its shell and casing. The test procedure shall be specified by the manufacturer. If the manufacturer does not specify the test procedure, the test should be carried out as follows: Heat the unpowered capacitor so that all parts reach a temperature not lower than the maximum value listed in Table 1 plus 20°C, and keep it at this temperature for at least 2 hours. No leakage should occur, and the permanent deformation of the oil tank should be less than the specified value.
6.4 Capacitance measurement
6.4.1 The capacitance measurement should be carried out in a way that can eliminate the errors caused by harmonics and accessories in the measurement circuit. 6.4.2 After the withstand voltage test, the capacitance should be measured at a voltage of (0.8~1.2)f and (0.9~1.1)U. 6.5 Withstand voltage test
6.5.1 The withstand voltage test of capacitors is generally carried out in accordance with the relevant provisions in GB/T16927.1 and the following supplementary instructions. 6.5.2 When conducting the power frequency withstand voltage test, the voltage should start from half of the rated voltage or lower. It should be evenly increased to the test value within 2s~10s and maintained at the test voltage for the required time. 6.5.3 When conducting the power frequency withstand voltage test of the capacitor’s line terminal to the oil tank, all the terminals of the capacitor insulated from the oil tank except the auxiliary circuit terminals shall be connected together, and the auxiliary circuit terminals shall be connected to the oil tank together, and the voltage shall be applied between the connected terminals and the oil tank. This test is not performed during the factory test for capacitors with one line terminal fixed to the oil tank. During the type test, the model with only the bushing and the internal insulation bracket but no internal capacitor unit may be tested. If the manufacturer can provide a type test report indicating that the product has been tested, this test may not be performed during the type test. 7
JB7112-2000
When conducting the power frequency withstand voltage test of the auxiliary circuit terminal to the oil tank, all the outlet terminals shall be connected together, and the voltage shall be applied between the connected terminals and the oil tank.
For indoor products, this test is only a dry test. For outdoor products, a dry test is performed during the factory test, and a wet test should be performed during the type test. If the manufacturer can provide a type test report indicating that the bushing can withstand a 1-minute power frequency wet test voltage, then outdoor products can also be tested dry only during type testing. 6.5.4 The lightning impulse test is carried out between the terminals other than the auxiliary circuit terminals that are insulated from the oil tank and the oil tank (the auxiliary circuit terminals are connected to the oil tank), and the impulse test voltage and waveform are selected from Table 4. Apply 15 impulses for each polarity. If no more than two flashovers and no breakdown occur in the 15 consecutive impulses, the test is considered to have passed. When changing polarity, it is allowed to apply several impulses with lower amplitudes first, and then apply the specified impulse test. 6.5,5 For multi-phase units where each phase is not connected, the phase-to-phase insulation should be subjected to the same power frequency voltage test between the poles and the oil tank and the (1.2~5)/50μs lightning impulse voltage test, and 3 impulses should be applied for each polarity. 6.5.6 During the test, check whether the capacitor is damaged according to the indication of the instrument, the discharge sound, observation or repeated capacitance measurement. 6.6 Discharge device inspection
The discharge efficiency of the discharge device can be inspected by the discharge method. If the discharge device is a resistor type, it can also be tested by measuring the resistance. The calculation after measurement shall be carried out according to D5 in Appendix D of the standard "Parallel capacitors for AC power systems with nominal voltages above 1kV". This inspection should be carried out after the withstand voltage test.
Note: For the discharge coil, if there is a type test report proving that its discharge performance can meet the requirements, the test is not required. 6.7 Measurement of loss tangent
The loss tangent of the capacitor should be measured at voltages of (0.8~1.2) and (0.9~1.1)U. Note: For capacitors with discharge coils installed inside, the connection wires should be removed before measurement. 6.8 Temperature rise test
The temperature rise test is to connect the whole capacitor to the rated frequency of the actual sine wave voltage at room temperature, and make its capacity reach 1.35QNg
There should be enough time for the temperature rise to stabilize during the test. The upper oil temperature is measured every 1h~2h with a thermometer with a thermal time constant of about 1h. When the change of temperature rise does not exceed 1K for 4 consecutive measurements within 6h, the temperature is considered to be stable. 6.9 Discharge test
The capacitor is charged to 2.5UN with direct current, and then discharged through the gap as close to the capacitor as possible. Such discharge should be completed 5 times within 30min. Then follow the requirements of 5.2.13 to carry out an inter-electrode withstand voltage test. The capacitance is measured before and after the discharge test, and there should be no obvious difference between the two measurements.
Capacitors with internal discharge coils should be tested after the discharge coil is disconnected. 6.10 Insulating oil test
The test is carried out in accordance with the relevant standards.
For the insulating oil before being placed in the oil tank, an oil sample should be taken from the oil storage tank. After the insulating oil is placed in the oil tank, the oil sample should be taken from the oil sample valve at the bottom of the oil tank.
6.11 Test of internal capacitor unit
6.11.1 The thermal stability test of the internal capacitor unit shall be carried out in a constant temperature oil tank, and the oil temperature shall be controlled at the upper limit temperature of the temperature category of the assembled capacitor composed of it plus 15℃ and kept constant. The temperature of the oil shall be measured with a thermometer. When all parts of the test unit have reached the temperature specified in the above 8
JB7112-2000
, an actual sinusoidal AC voltage shall be applied to the test unit for 48 hours. During the entire test process, the capacity of the unit shall be equal to 1.44Qn and kept constant.
During this test, the hottest point temperature inside the core and the temperature of the box shell shall be measured every 2 hours. The hottest point temperature inside the core shall be measured at least 4 times in the last 6 hours of the test process, and the temperature increment within this 6 hours shall not be greater than 1K. If exceeded, the test shall be continued until the values of the four consecutive measurements within 6 hours meet the above requirements. 6.11.2 The partial discharge test of the internal capacitor unit can be carried out simultaneously with the inter-electrode electrical strength test. The test voltage used shall be the actual sine wave power frequency voltage, and the test circuit shall be properly damped to reduce the overvoltage caused by the transition process. During the test, the voltage shall be evenly raised to 2.15Un in the test unit within 2s~10s, and maintained for 10s, then the voltage shall be quickly reduced to 1.2Un and maintained for 1min, and then the voltage shall be increased to 1.5Un and maintained for 1min. No increase in partial discharge shall be observed in the last 1min. 6.11.3 The remaining tests of the internal capacitor unit shall be carried out in accordance with the current standard of "Parallel Capacitors for AC Power Systems with Nominal Voltages of 1kV and Above". If the creepage distance of the external insulation is not enough, it can be carried out in the oil tank. 2 Bushing Mechanical Strength Test
According to the provisions of 5.2.17, a tensile force perpendicular to the central longitudinal axis of the bushing shall be applied to the top of the bushing for 5 times within 10min. 7
Inspection Rules
7.1 Classification of Tests
The tests are divided into factory tests, type tests and acceptance tests. Note: Take typical samples of internal capacitor units for durability test to check their design. 7.2 Factory test Factory test is carried out by the manufacturer on each capacitor produced. See Table 6 for test items. Table 6 Test items
Test category
Factory test
Type test
Test items
Appearance and supporting device inspection
Sealing test
Inter-pole withstand voltage test
Power frequency withstand voltage test between poles and oil tank and between phases (dry test)Capacitance measurement
Discharge device inspection
Loss tangent measurement
Insulating oil test
Discharge test
Power frequency withstand voltage test between poles and oil tank (wet test)Lightning impulse withstand voltage test between poles and oil tank and between phasesTemperature rise test
Test on internal capacitor unit
Bushing mechanical strength test
Note: The listed order is the recommended order. Manufacturers can choose the best order according to their own characteristics. 7.3
Type test
Technical requirement number
5.2.2~5.2.7
Test method number
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