Some standard content:
JB/T8958--1999
This standard is prepared with reference to GB/T3983.2--1989 "High Voltage Shunt Capacitors", GB/T12747-1991 "Self-healing Low Voltage Shunt Capacitors" and related materials. This standard is consistent with the relevant standards and conforms to the provisions of GB/T1.1-1993 in the format of preparation. Appendix A of this standard is the standard appendix.
Appendix B of this standard is the reminder appendix.
This standard is proposed and managed by the National Technical Committee for Standardization of Power Capacitors. The drafting unit of this standard: Guilin Power Capacitor General Factory. The main drafter of this standard: Guo Dade.
This standard is entrusted to the National Technical Committee for Standardization of Power Capacitors for interpretation. 433
1 Scope
Machinery Industry Standard of the People's Republic of China
High voltage shunt capacitor of the self-healingtypeJB/T8958--1999
This standard specifies the technical requirements, test methods, inspection rules and markings of self-healing high voltage shunt capacitors. This standard applies to self-healing high voltage shunt capacitors connected in parallel in AC power systems with a rated voltage of more than 1000V and a frequency of 50Hz to improve the power factor. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, 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/T3983.2--1989 High voltage parallel capacitors (eqvIEC60871-1:1987) GB/T16927.1-1997 High voltage test technology Part 1: General test requirements (eqvIEC60060-1:1989) GB50227-1995 Parallel capacitor device design specification JB/T7613-1994 General technical conditions for power capacitor product packaging 3 Definitions
This standard adopts the following definitions.
3.1 Capacitor element (or element) capacitorelement (orelement) A component consisting of a dielectric and electrodes separated by it. 3.2 Capacitor unit (or unit) capacitorunit (orunit) An assembly composed of one or more capacitor elements assembled in a single housing and having lead terminals. 3.3 Capacitor bank capacitorbank
A group of capacitor units electrically connected together. 3.4 Capacitor
In this standard, the term "capacitor" is used when there is no need to emphasize "capacitor unit" or "capacitor bank". 3.5 Line terminals
Terminals used to connect to transmission lines or busbars. Note: In multi-phase capacitors, the terminals intended to be connected to the neutral line are not called line terminals. 3.6 Discharge device
A device installed inside or outside the capacitor that can reduce the voltage on the capacitor terminals to a specified value within a specified time when the capacitor is disconnected from the power supply.
3.7 Internal fuse internal fuse
A fuse connected in series with the component inside the capacitor unit. 3.8 Rated frequency (f.) ratedfrequency (f.) The frequency specified when designing the capacitor.
Approved by the State Bureau of Machinery Industry on August 6, 1999 434
Implemented on January 1, 2000
3.9 Rated voltage (U.) ratedvoltage (U.) JB/T8958—1999
The voltage (RMS value) specified when designing capacitors. Note: When a capacitor consists of one or more independent circuits, U. refers to the rated voltage of each circuit. For multi-phase capacitors with the same internal connections, and multi-phase capacitor banks, U. refers to the line voltage. 3.10 Rated capacitance (C.) ratedcapacitance (C,) The capacitance value specified when designing capacitors. 3.11 Rated current (I.) ratedcurrent (I.) The current (RMS value) specified when designing capacitors. 3.12 Rated capacity (Q) ratedoutput (Q.) The reactive power calculated from the rated frequency, rated voltage (or rated current) and rated capacitance. 3.13 Loss loss
The active power consumed by the capacitor.
Note: The loss of the capacitor should include the loss generated by all components. For example: for the unit, it should include the loss generated by the dielectric, internal fuse, internal discharge device, connector, etc.; for the capacitor bank, it should include the loss generated by the unit, external fuse, busbar, discharge resistor and damping reactor, etc. 3.14 The ratio of the loss angle (tano) tangent of the loss angle (tand) The ratio of the loss of the capacitor to the reactive power. 3.15 Maximum allowable voltage maximum per missible voltage Under specified conditions, the maximum AC voltage (root mean square value) that the capacitor can withstand for a given time 3.16 Maximum allowable current maximum per missible current Under specified conditions, the maximum AC current (root mean square value) that the capacitor can withstand for a given time 3.17 Steady-state steady-state condition The thermal equilibrium state reached by the capacitor at a constant output and a constant ambient air temperature. 3.18 Ambient air temperature ambient air temperature The air temperature at the location where the capacitor is to be installed. 3.19 Cooling air temperature cooling air temperature The air temperature at the midpoint of the hottest point of the shell between the two units in the hottest area of the capacitor bank under stable conditions. If there is only one unit, it refers to the temperature at 0.1m from the hottest point of the capacitor shell. 3.20 Residual voltage residual voltage
The voltage remaining between the capacitor terminals after a period of disconnection. 3.21 Self-healing capacitor self-healing capacitor A capacitor with self-healing properties.
4 Classification
4.1 Ambient air temperature category
The ambient air temperature range in the installation and operation area is: -50 to +55℃. Capacitors are classified according to temperature categories, and each temperature category is represented by the lower limit temperature value and the letter code of 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. Its value is selected from the five values of +5℃, 5℃, 25℃, -40℃, and -50C. The upper limit temperature is the highest ambient air temperature at which the capacitor can operate continuously. The relationship between the letter code and the upper limit of the ambient air temperature 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: -40/A, -25/A, -25/B, -5/A and -5/C. The cooling air temperature during the operation of the capacitor should not exceed the highest ambient air temperature of the corresponding temperature category plus 5°C. 435
JB/T8958—1999
Table 1 is determined based on the use conditions where the ambient air temperature is not affected by the capacitor (such as outdoor devices). If the capacitor affects the ambient air temperature during operation, ventilation should be strengthened and/or capacitors should be selected so that the highest value in Table 1 is not exceeded. In such an installation, the cooling air temperature should not exceed the highest value in Table 1 plus 5°C. Special specifications negotiated by the manufacturer and the purchaser may be higher than the highest temperature value listed in Table 1. Its temperature category is expressed by the minimum and maximum temperature values, such as -40/60.
Table 1 Relationship between letter codes and upper limit of ambient air temperature
Note: The temperature values in the table can be obtained from meteorological data. 4.2 Rated voltage
The preferred values of the rated voltage of capacitors are as follows: ambient air temperature, ℃
24h average maximum
1.05, 3.15, 6.6/3, 6.3, 10.5, 11/3, 11, 12/3, 12, 19kV. Note: The manufacturer is allowed to manufacture capacitors with other rated voltages according to the needs of the purchaser. 4.3 Rated capacity
The preferred values of the rated capacity of capacitors are as follows: 50, 100, 150, 200, 250, 300, 334, 400, 500kvar. Note: The manufacturer is allowed to manufacture capacitors with other rated capacities according to the requirements of the purchaser. 5 Requirements
5.1 Usage requirements
5.1.1 Altitude
The altitude of the installation and operation area shall not exceed 1000m. 5.1.2 Ambient air temperature
The ambient air temperature of the installation site shall comply with the temperature category corresponding to the capacitor. 5.1.3 Earthquake
The earthquake intensity of the installation and operation area shall not exceed 8 degrees. 5.1.4 Pollution
The annual average maximum
The atmospheric pollution level of the installation and operation area shall not exceed level I, and the creepage distance of the corresponding capacitor terminals shall not be less than 25mm/kV. 5.1.5 Chemical conditions
The installation and operation site shall be free of harmful gases and vapors, and conductive or explosive dust. 5.1.6 Mechanical conditions
The installation and operation site shall be free of severe mechanical vibration. 5.1.7 Allowable overload
5.1.7.1 Steady-state overvoltage
The capacitor shall be able to operate at the voltage level shown in Table 2. The overvoltage amplitude that the capacitor can withstand without significant damage depends on the duration of the overvoltage, the number of times it is applied and the temperature of the capacitor. The overvoltages above 1.15U in Table 2 are determined on the premise that they will not exceed 200 times in total during the entire service life of the capacitor. 436
Power frequency plus harmonics
Voltage factor XU,
(Root mean square value)
JB/T8958--1999
Table 2 Permissible voltage level in use
Maximum duration
The highest average value during any period of capacitor energization For continuous energization
12h in every 24h
30min in every 24h
The current does not 5.1.7.2 Operating overvoltage and overcurrent
Exceptional cases where the duration is less than 24 h, the following values apply (see also A4)
Regulation and fluctuation of system voltage
Voltage rise at light load
When switching capacitors with switches that do not break down, a transient overvoltage with a first peak value not exceeding 22 times the applied voltage (rms value) and a duration not exceeding 1/2 cycle may occur. The corresponding transient overcurrent peak value may reach 100I. In this case, 1000 operations per year are allowed. When the capacitor needs to be operated more frequently, the magnitude and duration of the steady-state overvoltage and the transient overcurrent should be limited to a lower level. The limit values are determined by negotiation between the manufacturer and the purchaser. 5.1.7.3 Steady-state overcurrent
Capacitors shall be suitable for continuous operation at a steady-state overcurrent 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 1.10Ca, this overcurrent may reach about 1.43I. This overcurrent is the result of the combined effect of harmonics and overvoltages up to 1.10U. 5.1.7.4 Maximum allowable capacity
The total capacity of the capacitor shall not exceed 1.35Q, taking into account the steady-state overvoltage, steady-state overcurrent and positive deviation of capacitance.
5.1.7.5 Power frequency plus harmonic overvoltage
The power frequency plus harmonic overvoltage during capacitor operation shall not cause the overcurrent to exceed the value specified in 5.1.7.3. If the capacitor is operated for a long time at not more than 1.10U, the voltage peak value including all harmonic components shall not exceed 1.22Un.
Note: When the capacitor needs to be installed in an environment that does not comply with the provisions of this article, the purchaser should negotiate with the manufacturer. 5.2 Performance and structural requirements
5.2.1 Discharge device
If a discharge device is installed inside the capacitor, the discharge device should be able to reduce the residual voltage on the capacitor from /2U to below 75V within 10min.
Note: According to the needs of the purchaser, a discharge device that can reduce to a lower voltage in a shorter time can be installed. 5.2.2 Appearance and anti-corrosion layer
The appearance of the capacitor should meet the requirements of the product drawings. Its exposed metal parts should have a good anti-corrosion layer. 5.2.3 Grounding terminal
Metal shell capacitors should have a terminal for grounding the shell or fixing the potential. 5.2.4 Sealing performance
Fully sealed capacitors should have good sealing performance. 5.2.5 Capacitance deviation
The deviation between the capacitor capacitance measured in accordance with 6.3 and its rated value should not exceed: 0~10%. 437
JB/T8958—1999
The ratio of the maximum capacitance to the minimum capacitance measured between any two line terminals of a three-phase capacitor: for a capacitor unit, it should not exceed 1.06; for a capacitor bank, it should not exceed 1.02.5.2.6 Loss tangent (tangent)
The loss tangent of the capacitor at 20°C under the rated power frequency AC voltage should not be greater than 0.0005.5.2.7 Dielectric strength of dielectric
The insulation between the capacitor line terminals must be able to withstand the test voltage specified in Table 3 for 10S, and no permanent breakdown or flashover should occur, but self-healing breakdown is allowed.
Table 3 Test voltage between terminals
Test voltage type
Power frequency AC voltage
Type test
If you want to re-perform the withstand voltage test on the capacitor that has been sent. It is recommended to use 75% of the above specified value. For multi-phase capacitors, the test voltage should be adjusted so that each phase can be subjected to the specified voltage. Type
Factory test
When the impedance of the unit or capacitor bank with grounded neutral point is too high to effectively mitigate the overvoltage of the system, and the capacitor bank is not protected against lightning and switching overvoltage, the power test voltage should be the value of the withstand voltage of the terminal to the shell (ground). If the units are connected in series in the capacitor bank, the test voltage is determined proportionally.
5.2.8 Insulation level
5.2.8.1 The insulation between all terminals of the capacitor and the shell (ground) should be able to withstand the withstand voltage listed in Table 4. The short-term power frequency withstand voltage is applied for 1 minute. When the outdoor products are tested, they should be tested under rain. Table 4 Insulation level
Insulation level of capacitors
Short-time rated withstand voltage\
Root mean square value
1) The data under the slash line in this column is the external insulation withstand voltage of this type of capacitor. 5.2.8.2 The corresponding insulation level of the rated voltage of the capacitor is shown in Table 5. Insulation
Table 5 The corresponding insulation level of the rated voltage of the capacitor Rated voltage of the capacitor
Insulation level
5.2.9 Short-circuit discharge withstand capability
6.6/3,6.3
Lightning impulse withstand voltage
(1.2~5)/50μs Peak value
10.5,11/3,11,12/3,12
The capacitor must be able to withstand short-circuit discharge caused by external faults at the allowable operating voltage. 5.2.10 Internal fuse
If the capacitor is equipped with an internal fuse, the fuse should be able to isolate the damaged component or unit when the capacitor breaks down within the range of u and u2, where u1 and u2 are the lowest and highest instantaneous values of the voltage between the capacitor terminals at the moment of the fault. The recommended values of u1 and u2 are 0.92U. and 2.02U. respectively.
JB/T8958-1999
The fuse gap after the action must be able to withstand the steady-state voltage and normal short-time transient overvoltage that may appear on the component it isolates. During the entire life of the capacitor, the fuse should be able to continuously bear a current equal to or greater than the maximum allowable value of the capacitor current divided by the number of parallel fuse paths, the discharge current when other internal components or units are damaged and the external short circuit occurs. 5.2.11 Self-healing performance
The capacitor should have good self-healing performance. The capacitance before and after the test should not change significantly. 5.2.12 Aging resistance
The capacitor should be able to withstand the aging test specified in 6.11. The change in capacitance before and after the test should not be greater than 3%; the loss increment should not be greater than 0.02%.
5.2.13 Ability to withstand damage
After failure, the capacitor should not have hazards such as combustion and explosion. 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 between +5 and +35°C. If correction is required, the value at +20°C shall prevail. The temperature of the capacitor should not be significantly different from the ambient air temperature. After being placed in a constant ambient air temperature for an appropriate period of time without power, the temperature of the capacitor's dielectric is considered to be the same as the ambient temperature;
b) The waveform of the AC voltage used for testing and measurement should be an actual sinusoidal waveform (see GB/T16927.1). 6.2 Sealing test
This test is only carried out on fully sealed capacitors. During the test, all parts of the capacitor are heated to the maximum allowable operating temperature of the dielectric and maintained for at least 2 hours. No leakage should occur. It can also be carried out by an equivalent method that has been verified to be effective. If the capacitor does not contain a liquid medium, this test can be omitted. 6.3 Measurement of capacitance
The capacitance measurement should be carried out in a method that is sufficient to eliminate the error caused by harmonics and accessories in the circuit other than the capacitor being tested. The measured capacitance should meet the requirements of 5.2.5.
In order to reveal whether there is a capacitance change caused by the breakdown of a component or the blowing of an internal fuse, the initial capacitance measurement should be carried out with a voltage not higher than 0.15U before other electrical tests; after the withstand voltage test, the capacitance should be re-measured with a voltage of (0.8~1.2)f. and (0.9~1.1)U.
If the manufacturer and the purchaser agree on appropriate correction factors, the capacitance measurement can be carried out at other voltages. Notes
1 For multi-phase capacitors, the measuring voltage should be adjusted so that each component or unit can be subjected to (0.9~1.1) times the rated voltage. 2 When obtaining an agreement, the manufacturer should provide a curve or table showing the following relationships: a) The functional relationship between the capacitance and the ambient temperature (within the temperature category range) under steady-state conditions when the output of the capacitor is rated capacity; b) The functional relationship between the capacitance and the dielectric temperature (within the range of the lower limit of the temperature category to 100C). 6.4 Withstand voltage test
6.4.1 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. 6.4.2 When conducting the power frequency withstand voltage test, the voltage should start from half of the rated voltage of the capacitor or lower. It should be evenly increased to the test value within 210s and maintained at the test voltage for the required time. 6.4.3 In the withstand voltage test of the terminal to the shell (ground), the terminals on the capacitor that are insulated from the shell (ground) should be connected together, and the voltage should be applied between the common joint and the shell (ground). Capacitors with one terminal fixed to the shell (ground) are not subject to this test. For multi-phase capacitors whose phases are not connected, the phase insulation should be subjected to the same voltage test as that between the terminal and the shell (ground). This test is only a dry test for indoor capacitors; for outdoor capacitors, a dry test is performed during the export 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, outdoor capacitors can also be tested only during the type test. 6.4.4 The impulse test is performed between the connected line terminals and the shell (ground), and the impulse test voltage and waveform are selected from Table 4. Each polarity is applied 15 times. If no more than two flashovers and no breakdown occur in the 15 consecutive impacts, the test is considered to have been passed.
6.4.5 During the test, the capacitor shall be checked for damage according to the indication of the instrument, the discharge sound, observation or repeated capacitance measurement. 6.5 Inspection of discharge device
The discharge efficiency of the discharge device installed in the capacitor can be measured by the actual discharge method. The calculation after measurement is shown in B5. If the discharge device is a resistor type, it can also be carried out by measuring the resistance. This test should be carried out after the withstand voltage test.
6.6 Measurement of loss tangent
The loss tangent of the capacitor should be measured at a voltage of (0.8～1.2) to (0.9～1.1) U. The measurement accuracy should not be less than 0.02%, and the measured loss tangent should meet the requirements of 5.2.6. 6.7 Thermal stability test
This test is carried out on the unit.
During the test, the unit under test shall be placed between two other identical units (companion test units). The distance between them shall be equal to or less than the minimum value that the manufacturer wishes the purchaser to adopt. The same voltage shall be applied during the test. The companion test unit may also be a simulation unit with a resistor installed in the same housing. The power consumed by the resistor shall be adjusted to make the temperature near the top of the wide surface of the simulation unit housing equal to or slightly higher than the temperature at the corresponding part of the unit under test.
The test group shall be placed in a closed constant temperature box with still air. The air temperature in the box shall comply with the provisions of Table 6 and remain constant. This temperature shall be detected by a thermometer with a thermal time constant of about 1h. The thermometer shall be shielded so that the heat radiation disks of the three energized units are minimized. When all parts of the unit have reached the corresponding temperatures specified in Table 6, an actual sinusoidal AC voltage shall be applied to the unit for 48h. During the entire test process, the capacity of the unit shall be equal to 1.58Q. and remain constant. In the last 6 hours of the test process, the temperature near the top of the housing should be measured at least 4 times (once every 2 hours). The increment of temperature rise in this 6 hours shall not exceed 1°C. If exceeded, the test shall be continued until the above requirements are met for 4 consecutive measurements within 6 hours. When testing outdoor products, the ambient air temperature shall be 5°C higher than the corresponding value in Table 6. Table 6 Ambient air temperature of test piece during thermal stability test Number
Ambient air temperature of test piece
Temperature deviation
Before and after the thermal stability test, the capacitance shall be measured within the standard test temperature range (see 6.1) and calibrated to the same dielectric temperature. The difference between the two values shall not exceed 2%.
When interpreting the test results, the following two factors should be noted: a) Reproducibility of measurement:
b) In the absence of component breakdown or fuse blowing, the inherent changes in the dielectric may cause slight changes in capacitance. During the test, the fluctuation of voltage, power and the air temperature around the test object shall be considered. For this purpose, it is recommended to draw the function curve of these parameters and the unit loss tangent value or the shell temperature to time. It is recommended to draw the function curve of the unit loss tangent value to the shell or dielectric temperature. 6.8 Discharge test
The capacitor is charged to 2U with direct current, and then discharged through the gap as close to the capacitor as possible. Such a test should be completed 5 times within 10min440
JB/T8958-1999
, followed by an inter-electrode withstand voltage test according to 5.2.7 within 5min. The capacitance is measured before the discharge test and after the withstand voltage test. The difference between the two measured values should be less than 2%. If the first peak value of the test current exceeds 2001. (root mean square value), the external coil method can be used to maintain this limit value.
6.9 Internal fuse test
This test is carried out on the unit and the test is carried out in accordance with the relevant provisions of the internal fuse test of high-voltage shunt capacitors. 6.10 Self-healing test
This test is carried out on the unit or its components. The unit or component shall be subjected to an AC voltage of 1.75U. for 10°s. If less than 5 breakdowns occur during this period, the voltage shall be increased slowly until 5 breakdowns occur from the start of the test or the voltage rises to 3.5U. If the voltage has reached 3.5U. and less than 5 breakdowns occur, the voltage application time is extended until 5 breakdowns are obtained or the test is interrupted and repeated on another identical unit or component. The capacitance measured before and after the test shall not have any significant change in value. Note
1 Breakdowns during the test can be detected by an oscilloscope, the sound method or the high-frequency test method. 2 For multi-phase units, the test voltage should be appropriately adjusted accordingly. 3 When comparing the capacitance measurement results before and after the test, two factors should be considered: a) the reproducibility of the measurement;
b) internal changes in the dielectric may cause small capacitance changes that are not harmful to the unit. 6.11 Aging Test
This test is conducted on units.
6.11.1 Test Conditions
During the aging test, the temperature of the unit housing shall be the average maximum temperature for 24 hours (see Table 1 of 4.1) plus the difference between the housing temperature and the cooling air temperature recorded for the same unit at the end of the thermal stability test. The two methods described below are both used to ensure that the unit housing temperature remains constant during the test. The two methods are considered to be equivalent.
6.11.1.1 Test in forced circulating air Place the unit under test in a constant temperature chamber with hot air circulating at a rate that causes the temperature change at any point in the constant temperature chamber to not exceed ±2°C. The temperature sensitive element of the constant temperature chamber shall be placed at three quarters of the distance from the center line of the wide side of the housing of the unit under test from bottom to top. The unit shall be placed vertically with the lead-out terminal pointing vertically upward. When more than two units are tested together, the gap between them shall be not less than twice the width of the narrow side to ensure sufficient temperature uniformity. After placing the unit in an unheated thermostat, adjust the temperature controller so that the temperature in the thermostat is equal to the value specified in 6.11.1. When all parts of the unit have reached the specified temperature, perform the test according to the test procedure in 6.11.2. 6.11.1.2 Test in a liquid tank
Immerse the unit in a container filled with liquid and heat the liquid in an appropriate manner so that the temperature of the heated liquid remains at the value specified in 6.11.1 throughout the test.
When all parts of the unit have reached the specified temperature, perform the test according to 6.11.2 Test procedure Carry out the test. Note: When the line terminals or connecting cables on the unit are likely to be damaged by the heated liquid, they are allowed to just be exposed to the liquid surface. 6.11.2 Test procedure
6.11.2.1 During the entire test, the temperature of the housing should be maintained at the value specified in 6.11.1. 6.11.2.2 See Table 7 for the test voltage and duration. Table 7
Test voltage
Duration, h
Test voltage and duration
JB/T8958—1999
6.11.2.3 When the test reaches 1/2 of the specified duration, the unit should be taken out and cooled to ambient temperature, and then the following charge and discharge test should be carried out.
Charge the unit to √2U (DC), and then discharge it through an inductor of L=(1000/C)pH±20% (C is the measured capacitance, μF). The time interval between two discharges should be at least 30s, and it should be carried out 500 times. If the capacitance change of the unit after the charge and discharge test is equal to or greater than 2%, the test is terminated. If the capacitance change is less than 2%, continue to conduct the power-on test according to Table 7 until the specified duration is accumulated. 6.11.3 Test requirements
After the test, measure the capacitance and tgo and compare them with the test values before the test. They should meet the requirements of 5.2.12. 6.12 Destruction test
6.12.1 Test conditions
This test should be carried out on the unit, and the unit that has passed the aging test can be used. The principle of the test is to cause the component to fail with a DC voltage, and then apply an AC voltage to test its characteristics. 6.12.2 Test procedure
Figure 1 Circuit for destructive test
Place the unit in a constant temperature box, and the ambient air temperature in the box is the upper limit temperature of the temperature category of the unit being tested. The temperature should be kept as stable as possible during the whole test. The temperature should be measured with a thermometer with a thermal time constant of about 1h. When all parts of the unit have reached the temperature in the constant temperature box, complete the following test procedure according to the circuit in Figure 1. 6.12.2.1 Set the selector switches H and K to the "1" and "a" positions respectively, and set the AC power supply voltage to 1.3U. And record the current of the unit.
6.12.2.2 Set the DC power supply voltage to 10U. Then set switch H to the "2\ position, and adjust the variable resistor to make the DC short-circuit current 300mA.
6.12.2.3 Set switch H to the "*3" position and switch K to the "b" position, and apply a DC test voltage to the unit until the voltmeter indicates approximately zero, and keep it for 3 to 5s.
6.12.2.4 Then set switch K to the "a" position, apply an AC voltage to the unit for 3min, and record its current value again. The following situations may occur:
a) Both the ammeter and the voltmeter U indicate "zero". At this time, the fuse should be checked. If it has blown, it should be replaced and the AC voltage should be continued. If the fuse blows again, the test should be interrupted. If the fuse does not blow, the test of 6.12.2.5 should be carried out. b) If the current indicated by the ammeter I is higher than 66% of the initial value (the voltage meter U indicates the value is still 1.3U.), the test of 6.12.2.5 should be carried out.
6.12.2.5 Only switch K should be used to continue the DC-AC voltage test procedure specified in 6.12.2.3 and 6.12.2.4 for the unit, and the test should be repeated until the current indicated by the ammeter 1 drops below 66% of the initial value (the voltage meter indicates 1.3U.), and the test should be interrupted. 6.12.2.6 After the test is interrupted, the unit is allowed to cool naturally to the ambient temperature, and the withstand voltage test between the line terminal and the housing (ground) is carried out. Apply 1500V AC voltage for 10s.
6.12.3 Power supply and fuse
JB/T8958—1999
The short-circuit current of the AC test power supply should not be less than 2000A. A time-delay fuse should be used. The rated current of the fuse is 1, calculated as follows: I=KI10%
Where: K=100/Q (K should be within the range of 2 to 10 in any case); Q=Q. (single-phase capacitor), kvar;
I=In.A.
6.12.4 Requirements
After the test, the housing of the unit should be intact. Only if the following conditions are met, the exhaust hole is allowed to operate normally or the housing has minor damage (such as cracks).
a) The escaping liquid material can wet the outer surface of the unit, but shall not drop; b) The unit shell may be deformed and damaged, but shall not be broken; c) There shall be no flames and/or sparks (i.e. burning particles) ejected from the opening. This can be checked by wrapping the unit with gauze (cheesecloth), and the burning or scorching of the gauze shall be used as the criterion for failure; d) The withstand voltage test between the terminal and the shell (ground) (see 6.12.2.6) shall be passed. Note: Excessive smoke may be dangerous during the test. 7
Inspection rules
The capacitor test is divided into factory test, type test and acceptance test. 7.1 Factory test
The factory test is carried out by the manufacturer on each capacitor produced. See Table 8 for the test items. Table 8 Test items
Test category
Factory test
Type test
Appearance inspection
Test items
Sealing test
Capacitance measurement
Inter-electrode withstand voltage test
Pole-to-shell (earth) power frequency withstand voltage test (dry test) Remeasurement of capacitance
Discharge device inspection
Loss tangent measurement
Thermal stability test
Pole-to-shell (earth) power frequency withstand voltage test (mixed test) Lightning impulse withstand voltage test
Discharge test
Internal fuse test
Self-healing test
Aging test
Destruction test
The listed order is the recommended order, and the manufacturer can choose the best order according to its own characteristics. Technical requirements Article No.
5.1.4 and 5.1.7
2 For capacitor banks, the tests in Items 9 and 13 to 16 are to be conducted on the unit, and the remaining tests are to be conducted on the capacitor bank. Test method Article No.4 Then put switch K in position "a", apply AC voltage to the unit for 3 minutes, and record its current value again. The following situations may occur:
a) Both the ammeter and the voltmeter U indicate "zero". At this time, the fuse should be checked. If it has blown, replace it and then continue to apply AC voltage. If the fuse blows again, interrupt the test: If the fuse does not blow, perform the test in 6.12.2.5; b) The current indicated by the ammeter I is higher than 66% of the initial value (the voltmeter U indicates the value is still 1.3U.), then perform the test in 6.12.2.5.
6.12.2.5 Only use switch K to continue to perform the DC-AC voltage test procedures specified in 6.12.2.3 and 6.12.2.4 on the unit, and repeat until the current indicated by the ammeter I drops below 66% of the initial value (the voltmeter indicates 1.3U.), then interrupt the test. 6.12.2.6 After the test is interrupted, the unit is allowed to cool naturally to the ambient temperature, and a withstand voltage test is performed between the line terminal and the housing (ground). Apply 1500V AC voltage for 10s.
6.12.3 Power supply and fuse
JB/T8958—1999
The short-circuit current of the AC test power supply should not be less than 2000A. A time-delay fuse should be used. The rated current of the fuse is 1, calculated as follows: I=KI10%
Where: K=100/Q (K should be within the range of 2 to 10 in any case); Q=Q. (single-phase capacitor), kvar;
I=In.A.
6.12.4 Requirements
After the test, the housing of the unit should be intact. Only if the following conditions are met, the exhaust hole is allowed to operate normally or the housing has minor damage (such as cracks).
a) The escaping liquid material can wet the outer surface of the unit, but shall not drop; b) The unit shell may be deformed and damaged, but shall not be broken; c) There shall be no flames and/or sparks (i.e. burning particles) ejected from the opening. This can be checked by wrapping the unit with gauze (cheesecloth), and the burning or scorching of the gauze shall be used as the criterion for failure; d) The withstand voltage test between the terminal and the shell (ground) (see 6.12.2.6) shall be passed. Note: Excessive smoke may be dangerous during the test. 7
Inspection rules
The capacitor test is divided into factory test, type test and acceptance test. 7.1 Factory test
The factory test is carried out by the manufacturer on each capacitor produced. See Table 8 for the test items. Table 8 Test items
Test category
Factory test
Type test
Appearance inspection
Test items
Sealing test
Capacitance measurement
Inter-electrode withstand voltage test
Pole-to-shell (earth) power frequency withstand voltage test (dry test) Remeasurement of capacitance
Discharge device inspection
Loss tangent measurement
Thermal stability test
Pole-to-shell (earth) power frequency withstand voltage test (mixed test) Lightning impulse withstand voltage test
Discharge test
Internal fuse test
Self-healing test
Aging test
Destruction test
The listed order is the recommended order, and the manufacturer can choose the best order according to its own characteristics. Technical requirements Article No.
5.1.4 and 5.1.7
2 For capacitor banks, the tests in Items 9 and 13 to 16 are to be conducted on the unit, and the remaining tests are to be conducted on the capacitor bank. Test method Article No.4 Then put switch K in position "a", apply AC voltage to the unit for 3 minutes, and record its current value again. The following situations may occur:
a) Both the ammeter and the voltmeter U indicate "zero". At this time, the fuse should be checked. If it has blown, replace it and then continue to apply AC voltage. If the fuse blows again, interrupt the test: If the fuse does not blow, perform the test in 6.12.2.5; b) The current indicated by the ammeter I is higher than 66% of the initial value (the voltmeter U indicates the value is still 1.3U.), then perform the test in 6.12.2.5.
6.12.2.5 Only use switch K to continue to perform the DC-AC voltage test procedures specified in 6.12.2.3 and 6.12.2.4 on the unit, and repeat until the current indicated by the ammeter I drops below 66% of the initial value (the voltmeter indicates 1.3U.), then interrupt the test. 6.12.2.6 After the test is interrupted, the unit is allowed to cool naturally to the ambient temperature, and a withstand voltage test is performed between the line terminal and the housing (ground). Apply 1500V AC voltage for 10s.
6.12.3 Power supply and fusebzxz.net
JB/T8958—1999
The short-circuit current of the AC test power supply should not be less than 2000A. A time-delay fuse should be used. The rated current of the fuse is 1, calculated as follows: I=KI10%
Where: K=100/Q (K should be within the range of 2 to 10 in any case); Q=Q. (single-phase capacitor), kvar;
I=In.A.
6.12.4 Requirements
After the test, the housing of the unit should be intact. Only if the following conditions are met, the exhaust hole is allowed to operate normally or the housing has minor damage (such as cracks).
a) The escaping liquid material can wet the outer surface of the unit, but shall not drop; b) The unit shell may be deformed and damaged, but shall not be broken; c) There shall be no flames and/or sparks (i.e. burning particles) ejected from the opening. This can be checked by wrapping the unit with gauze (cheesecloth), and the burning or scorching of the gauze shall be used as the criterion for failure; d) The withstand voltage test between the terminal and the shell (ground) (see 6.12.2.6) shall be passed. Note: Excessive smoke may be dangerous during the test. 7
Inspection rules
The capacitor test is divided into factory test, type test and acceptance test. 7.1 Factory test
The factory test is carried out by the manufacturer on each capacitor produced. See Table 8 for the test items. Table 8 Test items
Test category
Factory test
Type test
Appearance inspection
Test items
Sealing test
Capacitance measurement
Inter-electrode withstand voltage test
Pole-to-shell (earth) power frequency withstand voltage test (dry test) Remeasurement of capacitance
Discharge device inspection
Loss tangent measurement
Thermal stability test
Pole-to-shell (earth) power frequency withstand voltage test (mixed test) Lightning impulse withstand voltage test
Discharge test
Internal fuse test
Self-healing test
Aging test
Destruction test
The listed order is the recommended order, and the manufacturer can choose the best order according to its own characteristics. Technical requirements Article No.
5.1.4 and 5.1.7
2 For capacitor banks, the tests in Items 9 and 13 to 16 are to be conducted on the unit, and the remaining tests are to be conducted on the capacitor bank. Test method Article No.
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