JB/T 5871-1991 Line charging current opening and closing test for AC high voltage circuit breakers
Some standard content:
Mechanical Industry Standard of the People's Republic of China
Line Charging Current Opening and Closing Test of AC High Voltage Circuit Breakers JB/T5871-1991
This standard is formulated in accordance with the provisions of GB1984 "AC High Voltage Circuit Breakers" on line charging current opening and closing tests, and with reference to the relevant parts of the International Electrotechnical Commission Standard (IEC) 56 publication "High Voltage AC Circuit Breakers" (1987 Edition) and IEC427 publication "High Voltage AC Circuit Breakers Synthetic Test" (1989 Edition). 1 Subject Content and Scope of Application
This standard specifies the terms, rated parameters, power circuit and capacitive circuit characteristics, test conditions and methods of the line charging current opening and closing test of AC high voltage circuit breakers. This standard is only applicable to the line charging current opening and closing test of AC high voltage circuit breakers with rated voltage of 110kV and above 50IIz under normal conditions and ground fault conditions. This standard is also applicable to the charging current opening and closing test of overhead lines with a short cable in series, but the total charging current of the cable should be less than 20% of the charging current of the overhead line.
The line charging current opening and closing test of other high-voltage switchgear can be used as a reference. Note: If necessary, it can be extended to 63kV and 35kV circuit breakers. 2 Reference standards
GB11022
GB2900.19
GB2900.20
GB1984
3 Terms
General technical conditions for high-voltage switchgear
Electrical terminology Basic terminology
Electrical terminology High voltage test technology and insulation coordination Electrical terminology High voltage switchgear
Insulation coordination of high-voltage power transmission and transformation equipment
AC high-voltage circuit breakers
3.1 Line charging breaking current
Breaking current when breaking an unloaded overhead line under specified conditions. 3.2 Rated line charging breaking current
The maximum normal line charging current that the circuit breaker should be able to break under its highest voltage and the use and performance conditions specified in this standard, and the operating overvoltage does not exceed the provisions of this standard.
3.3 Overvoltage
Peak value exceeds any time-varying phase-to-phase voltage corresponding to the highest phase-to-phase voltage peak value (2
U.) or the highest phase-to-phase voltage peak value (2U.) of the circuit breaker. U. is the effective value of the highest voltage of the circuit breaker. 3.4 Phase-to-phase overvoltage standard value
The ratio of the peak value of the phase-to-phase overvoltage to the peak value of the phase-to-phase voltage corresponding to the highest phase-to-phase voltage of the circuit breaker (3.5 Circuit breaker operation overvoltage
Phase-to-phase overvoltage caused by circuit breaker operation. 3.6 Reignition
Ministry of Machinery and Electronics Industry, 1991-10-24 approved 16
U.).
1992-10-01 implementation
JB/T5871—1991
During the breaking process of the circuit breaker, the recurrence of the current between the contacts within 1/4 power frequency cycle after the current passes through zero. 3.7 Re-breakdown
During the breaking process of the circuit breaker, the recurrence of the current between the contacts within 1/4 power frequency cycle and longer after the current passes through zero. 3.8 Circuit breaker without re-breakdown
A circuit breaker that does not have re-breakdown during the line charging current breaking test of the test method specified in this standard. Rated parameters
Rated line charging breaking current
The rated line charging breaking current values of the circuit breaker are listed in Table 1. Rated line charging breaking current
Rated voltage
Rated line charging breaking current
125(160)
①For single-conductor overhead lines operating at 50H2 AC voltage, the line length value (in km) corresponding to the rated line charging breaking current given in Table 1 is approximately equal to 1.2 times the maximum voltage value of the circuit breaker (in kV). ?
The values in brackets are recommended values.
?35kV rated line charging breaking current value is under consideration. ④When it exceeds the requirements of Table 1, it shall be negotiated by the user and the manufacturer. 4.2 Rated rate
Rated frequency is 50Hz.
4.3 Maximum allowable operating overvoltage
Under the test conditions specified in this standard, the recommended maximum allowable operating overvoltage (relative to ground) when the circuit breaker breaks the specified line charging current is listed in Table 2.
Maximum allowable operating overvoltage when breaking
Maximum allowable operating overvoltage (relative to ground)
Per unit value
Per unit value
The values in this table are only applicable to the test conditions specified in this standard. Other overvoltages, such as overvoltages when closing lines with residual charge, overvoltages when breaking small inductance currents, and phase-to-phase overvoltages are not included in this standard. The values in column A are applicable to circuit breakers for opening and closing unloaded overhead lines in power systems. The values in column B are applicable to circuit breakers in power systems with special requirements for opening and closing unloaded overhead lines. This power system has special insulation coordination issues such as restrictions on the energy absorbed by lightning arresters and the discharge of spark gaps. The maximum allowable operating overvoltage value of a circuit breaker with a rated voltage of 63kV is determined based on a high voltage of 72.5kV. The maximum allowable operating overvoltage value of 35kV is under consideration. 17
5 General principles for testing
5.1 General provisions
JB/T58711991
The circuit charging current opening and closing test of the circuit breaker can be carried out on site or in the laboratory. For field tests, the actual line is used, with a power supply system on the power supply side and an overhead line on the load side. The test results are only valid for circuit breakers operating in the same line as the test circuit. For laboratory tests, the line is partially or completely replaced by an artificial circuit, which consists of concentrated components such as capacitors, reactors and resistors. Laboratory tests are only valid for circuit breakers without heavy breakdown. If the circuit breaker is without heavy breakdown and meets the requirements of Article 5.2, the single-phase test of the three-pole circuit breaker is valid. It is allowed to use concentrated capacitor banks for laboratory unit tests, but the requirements of Articles 5.2 and 5.3 must be met. When the capacity of the direct test equipment in the laboratory is insufficient, or its recovery voltage characteristics cannot meet the test requirements, a synthetic circuit can be used. The test requirements and methods are shown in Appendix A and B.
If the circuit breaker is not non-re-breakdown and the three-phase test cannot be carried out due to the limitation of the test equipment, a single-phase test or a test on the laboratory circuit can be used under the conditions negotiated between the manufacturer and the user. The line charging current opening and closing test under ground fault conditions is a test to break the charging current of the non-fault phase line under the condition of one or two phase ground fault in the line. This is a test item carried out under the conditions negotiated between the manufacturer and the user. Note: ① When using a capacitor bank for single-phase laboratory testing, it is allowed to replace the requirements for the test circuit with the recovery voltage requirements. ② The laboratory test circuit simulating the overhead line is not suitable for determining the overvoltage amplitude when a re-breakdown occurs, but is only suitable for verifying the opening and closing performance of the circuit breaker.
5.2 Single-phase test of three-pole circuit breakers
According to Article 7.11.3.1 of GB1984.
5.3 Unit test
According to Article 7.11.3.2 of GB1984.
Power supply circuit characteristics
Three-phase power supply circuit is used for three-phase test and single-phase field test. Single-phase power supply circuit is used for laboratory single-phase test. Line charging current opening and closing test shall be carried out on the specified two power supply circuits A and B. 6.1 Power supply circuit A
The impedance of power supply circuit A shall make its short-circuit current not exceed 10% of the rated short-circuit breaking current of the circuit breaker. If necessary, the power supply impedance value may be lower than the above requirements. However, the power frequency voltage change caused by the opening and closing capacitive current shall not exceed 10%. The expected transient recovery voltage of the power supply circuit shall be as close as possible to the transient recovery voltage of the outgoing line short-circuit test mode 2 specified in Article 5.13.3 of GB1984, but shall not be more severe than it, and the delay requirement does not need to be considered.
For the single-phase test in the laboratory, the transient recovery voltage parameter of test mode 2 specified in Article 5.13.3 of GB1984 shall be multiplied by the coefficient k/kt.
①k is the coefficient described in Article 11.2 of this standard, and ki is the first-opening phase coefficient quoted in Article 5.13.3 of GB1984 for test mode 2. ②In Table 3 of this standard, the impedance value of power supply circuit A in test mode 2 may be slightly different from that in test mode 1. 6.2 Power supply circuit B
The impedance of power supply circuit B shall be as small as possible, but the short-circuit current of the circuit shall not be greater than the rated short-circuit breaking current of the circuit breaker. The power frequency voltage change caused by the opening and closing capacitive current shall be as small as possible, and shall be less than 5% in any case for test mode 4. The expected transient recovery voltage of the power supply circuit shall not be more stringent than the transient recovery voltage of the outgoing short-circuit test mode 4 specified in Article 5:13.3 of GB1984. For the single-phase test in the laboratory, GB1984 Article 5.13.The transient recovery voltage parameter of test mode 4 specified in Article 3 shall be multiplied by the coefficient k/kt.
①k is the coefficient described in Article 11.2 of this standard, and k is the first-opening phase coefficient cited in Test mode 4 of Article 5.13.3 of GB1984. JB/T5871-1991
②If the circuit breaker is used in a system with a short cable of a certain length connected in series on the power supply side, appropriate additional capacitance should be considered on the power supply side. 7 Grounding of the power supply circuit
7.1 Grounding of the three-phase power supply circuit
The grounding of the power supply circuit shall correspond to the grounding condition of the line when the circuit breaker is used in principle. 7.1.1 The neutral point of the test power supply circuit of the circuit breaker used in the neutral point effective grounding system shall be grounded, and its zero sequence impedance shall be less than the positive sequence impedance of the three-phase power supply side. 7.1.2 The neutral point of the test power supply circuit of the circuit breaker used in the neutral point insulated or arc-extinguishing line grounding system shall be insulated or grounded through the arc-extinguishing line. 7.2 Grounding of single-phase power supply circuits in the laboratory
When single-phase tests are carried out in the laboratory, grounding can be done at either end of the power supply circuit. However, grounding can also be done at other points in the power supply circuit when it is necessary to ensure the correct voltage distribution between the various units of the circuit breaker. 8 Characteristics of the capacitive circuit to be opened
The capacitive circuit to be opened should have such characteristics that when it includes all necessary measuring devices. If a voltage divider is included, the voltage decay shall not be greater than 10% 100ms after the arc is finally extinguished. This can be appropriately relaxed during field tests. However, no device that affects the line voltage decay shall be connected. The following three capacitive circuits are valid for non-re-breakdown circuit breakers. a. When the circuit breaker is tested for three phases, several parallel lines are allowed. It is also allowed to partially or completely replace the actual three-phase line with a concentrated capacitor bank. But the total positive sequence capacitance should be close to twice the zero sequence capacitance; b. On-site single-phase test should use a three-phase power supply circuit, two phases of the capacitive circuit are directly connected to the three-phase power supply circuit, and the other phase is connected to the power supply circuit through the pole of the circuit breaker under test; c. In the laboratory single-phase test, it is allowed to partially or completely replace the actual line with a concentrated capacitor bank. When using a concentrated capacitor bank to simulate an overhead line, a non-inductive resistor can be connected in series with the capacitor, and its maximum resistance is 10% of the capacitive reactance. Higher resistance values will have an inappropriate effect on the recovery voltage. If the resistance is not enough to limit the closing inrush current, as long as the current and voltage conditions at the moment of breaking and the recovery voltage are not significantly different from the specified values, an alternative impedance (such as LR) can be used to replace the non-inductive resistor (regarding the alternative impedance characteristics, it is under consideration). 9 Test circuit frequency
The test circuit frequency should be the rated frequency, with a deviation of ±5%. Test current
The waveform of the test current should be close to a sine waveform, that is, the ratio of the effective value of the current to the effective value of its fundamental component should not be greater than 1.2. The test current shall not cross the zero point more than once in each half-wave of the working question. The test current of the line charging current opening and closing test under fault conditions: a. The neutral point grounding system is 1.25 times the rated line charging breaking current; b. The neutral point ungrounded system is 1.7 times the rated line charging breaking current. 11 Test voltage
11.1 Three-phase and single-phase field test
In three-phase and single-phase field tests, the phase-to-phase test voltage measured at the circuit breaker installation site just before the circuit breaker is tested and opened shall be as close to or equal to the highest voltage of the circuit breaker as possible.
11.2 Single-phase laboratory test
When using a concentrated capacitor bank for single-phase laboratory testing, the test voltage measured just before the circuit breaker is opened shall be as close to or equal to the product of u
JB/T5871-1991
and the following coefficient k, where U. is the maximum effective value of the circuit breaker voltage. 11.2.1 During the line charging current opening and closing test under positive load conditions. Neutral point grounding system k=1.2;
Neutral point ungrounded system k=1.4.
During the line charging current opening and closing test under single-phase or two-phase grounding fault conditions. 11.2.2
Neutral point grounding system k=1.4;
Neutral point ungrounded system k=1.7.
When the phase-to-phase opening of the circuit breaker exceeds 1/6 of the rated rate, the manufacturer and the user shall negotiate to further increase the test voltage. It is recommended that when the phase-to-phase opening is greater than 1/6 of the cycle and less than or equal to 1/4 of the cycle, the test voltage should be as equal to 1.05×k as possible. 11.3 Test voltage duration
After the circuit breaker extinguishes the arc, the power supply test voltage and the DC voltage duration of the disconnected circuit shall not be less than 0.3s. 12 Test methods
The line charging current opening and closing test includes four test modes specified in Table 3. Table 3 Test methods
Test methods
Current drawing
For three-phase tests, each test mode should include 10 tests. 0
The test current is a percentage of the rated line charging breaking current 20~40
For single-phase tests, phase control should be carried out, and each test mode should include 12 tests with the contact separation interval phase distributed by 30 electrical degrees 12.3 Operation sequence
12.3.1 For the line charging current opening and closing test under normal conditions, the last two tests in test modes 2 and 4 are carried out as "close open", and the remaining tests can be carried out as "open" or "close open". When carrying out the "open" and "close open" tests, the contacts of the circuit breaker shall not be separated before the transient charging current has completely decayed. Before the closing operation, there shall be no obvious residual charge on the capacitive circuit. 12.3.2 The operating sequence of the line charging current opening and closing test under ground fault conditions is the same as that specified in 12.3.1. However, for circuit breakers used in three-phase reclosing and neutral point grounding systems, additional tests of the reclosing operation mode under ground fault conditions can be carried out on site. If there are difficulties, the manufacturer can postpone the test after consultation with the user. 12.4 Alternative breaking test
The line charging current breaking test can be tested according to the recovery voltage requirements specified in the following figure and Table 4 instead of the requirements for the power circuit and capacitive circuit. The ratio of the recovery voltage value to the test voltage peak value
time coordinate
is equal to or greater than the value of 30% of the rated short-circuit breaking current in Tables 1 and 2 of GB1984. The value of
is equal to or greater than the value of 100% of the rated short-circuit breaking current in Tables 1 and 2 of GB1984. ≤8.7
13 Requirements for the circuit breaker under test
13.1 Before the test
JB/T5871—1991
Basically
(1--cosot) form
The expected recovery voltage of the line charging current breaking test shall comply with Article 7.11.2 of GB1984.
13.2 During the test
Comply with Article 7.11.6 of GB1984.
In addition, the circuit breaker shall not be adjusted or repaired during each test mode and between the four test modes, but inspection of the circuit breaker is allowed.
Note: For oil circuit breakers, oil change is allowed after two test modes. 13.3 After the test
Comply with Article 7.11.7.4 of GB1984.
14. Test Criteria
Under the test conditions specified in this standard, if the circuit breaker meets the following requirements after the test, it can be considered that the circuit breaker has passed the test. a.
The state of the circuit breaker under test fully complies with the provisions of Article 13. For circuit breakers without heavy breakdown, heavy breakdown should not occur during disconnection; for circuit breakers with heavy breakdown, three-phase tests should be carried out. In each test mode, the maximum operating overvoltage (relative to ground) measured shall not exceed the value specified in Table 2, and external flashover shall not occur. 15 Test report
According to Appendix A of GB1984.
In addition, if the test is conducted on site, the oscillogram should include the overvoltage to ground on the power supply side and the line side. The test report should make clear conclusions in accordance with the provisions of Article 14. Note: During the test, due to the limitations of the test conditions, abnormal overvoltages that are harmful to insulation may occur during the test, so that the provisions of the standard cannot be met.
A1 Introduction
JB/T5871-1991
Appendix A
Synthetic test method for switching capacitive current
(reference)
The closing and breaking tests of capacitive current by synthetic method are usually carried out on a single phase basis. Since the load of the circuit breaker during the capacitive current closing operation is small (except for back-to-back capacitor bank operation), closing and breaking can be carried out separately.
The re-ignition and restrike phenomena cause an interaction between the power supply and the capacitive load, which is currently difficult to simulate reliably with synthetic test circuits. Therefore, the synthetic method is only valid for processes without restrike. After re-ignition or restrike, the synthetic circuit conditions are no longer meaningful and direct testing is required. The pre-breakdown phenomenon that occurs during the closing operation provides the possibility of high-frequency current breaking. After this breaking, the relay occurs, which indicates that the circuit breaker may need to be directly tested. When switching long unloaded lines, traveling wave phenomena may occur, which can be simulated by envelope curves when using synthetic circuits. However, a more accurate simulation can be made by using additional circuits (such circuits are under consideration). Circuit breakers equipped with disconnecting shunt resistors can be tested in two steps according to synthetic test circuits. The parameters of the synthetic test circuit should be adjusted to produce a recovery voltage equivalent to the load of the direct test line. A2 Synthetic breaking test requirements
In order to take into account the phenomena related to breaking capacitive currents, the following items should comply with the provisions of the current standards. a.
The waveform and amplitude of the power frequency test current, especially the last half-wave before breaking. b.
The waveform and amplitude of the power frequency supply voltage.
The voltage on the load side after breaking.
The amplitude, frequency and damping of the transient voltage during the voltage mutation process when testing under conditions simulating high source impedance. e.
The electric field structure at both ends of the break and to the ground.
Synthetic Closing Test Requirements
In order to take into account the phenomena related to closing capacitive current, the following items shall comply with the provisions of the current standards. a. Amplitude and waveform of the voltage on the power supply side,
b. Residual voltage value on the line side (zero when closing under normal circumstances). When closing under residual voltage, the initial conditions on the line side must be considered and the synthetic closing circuit must be appropriately modified. C. Amplitude and waveform of the closing surge current.
A4 Cut-off
The cut-off phenomenon caused by the interaction between the circuit breaker and the test line usually causes a reduction in the voltage on the load side, thereby reducing the dielectric load of the test product.
In direct test circuits, when the capacitive test current is small, cutting may occur. In synthetic test circuits, the possibility of such cutting increases due to the following reasons:
Generally speaking, the characteristic parameters of the main components and the micro components of the test circuit are different, so the current-cutting characteristics of the circuit breaker may change;
b. The influence of the auxiliary circuit breaker in series with the circuit breaker under test; c. The increase in the ratio of arc voltage to working voltage. Therefore, when conducting synthetic tests, it is difficult to determine whether cutting is a significant feature of the circuit breaker. The following methods can be used to reduce the current. Change the capacitance seen from both ends of the circuit breaker; JB/T5871--1991
Use a special auxiliary circuit breaker with a short minimum arcing time and low arc voltage. A5 Synthetic test circuit
A5.1 Basic circuit for breaking test
In principle, the synthetic test circuit consists of two circuits, namely the current circuit and the voltage circuit. For capacitive current switching, these two circuits can be capacitive. As long as the phase angle between the two sources changes accordingly. In some cases, inductive or resistive current loops can be used as an alternative.
The two sources can be transformers fed by generators or charged capacitors, or a combination of the two. The combined circuit uses an auxiliary circuit breaker to isolate the circuit breaker under test from the current circuit. The connection of the two sources to the two circuit breakers can be of the parallel type (the voltage on the auxiliary circuit breaker is equal to the difference between the two source voltages) or of the series type (the voltage on the circuit breaker under test is equal to the sum of the two source voltages). Depending on whether the voltage circuit is permanently connected or connected at a certain moment before or after the zero point of the power frequency current, it can be distinguished as a power frequency current feeding circuit, a current introduction circuit or a voltage introduction circuit. In tests under high source impedance conditions, the sudden voltage of the state is preferably generated by the current or voltage circuit at the end of the circuit breaker where the AC voltage is applied. The other end of the circuit breaker must be loaded with a slowly decaying DC voltage. In some test circuits, the two voltages are applied to one end of the circuit breaker and the other end is grounded. This condition is more stringent in terms of insulation to ground. For metal enclosed circuit breakers, an additional voltage source may be connected to the case to compensate for this effect. There are various circuits with different characteristics, some examples of which are given in Figures A1 to A5. A5.2 Basic synthetic test circuit for making tests For capacitive synthetic making tests, the test voltage is applied by the voltage circuit from the moment the contacts close until dielectric breakdown, followed by the provision of the initial state making current. For this purpose, some special components may be required. After dielectric breakdown, the current circuit must be connected immediately to provide the transient making current and the subsequent power frequency current. For this purpose, the ball is ignited early in order to maintain the pre-breakdown current. In order to provide the required transient making current and power frequency current, a capacitive current source is suitable, while an inductive current source is not suitable because it does not give the correct current waveform. An example of a making circuit can be seen in Figure A6. Note that the formulas in Figures A1 to A6 are not accurate and only give approximate characteristics of the circuit. Symbols in Figures A1 to A6
a) Circuit schematic
b) Qualitative waveforms of current and voltage
c) Mathematical relationship between circuit parameters
Ratio of specified test voltage U. to actual voltage U. of current circuit n
m—Ratio of specified test current I, to voltage circuit current u,—Voltage across tested circuit breaker S. Ux, U.—Voltage to ground at points A and B. tai——Charging voltage of voltage circuit CL—Load capacitance S.—Test product S.—Auxiliary switch
Current circuit
Voltage U.=U./n
Current I=I (1-1/m)
Inductive reactance L<<1/C,
Capacitor C=n(1-
Line charging breaking current
JB/T5871
Breaking over
voltage circuit
voltage Uv=U.
Current Iv=IL/m
Inductive reactance WLv<<1/aC,
Capacitor Cv=Cz/m
Cr—load capacitance||tt ||Figure A1 Synthetic test circuit (parallel type)
The current circuit has a voltage U. and a capacitor C. to provide a capacitive current I. The voltage circuit provides the specified test voltage U, and together with the capacitor C, provides a smaller capacitive current I. 5
Current circuit
Voltage U.=-U./n
Current I. =I1-1/m)
Inductive reactance (L+L,)
n(1-1/m)wC,||tt| |JB/T5871—1991
Breaking process
Voltage circuit
Voltage U.=U.
Current IvI/m
Capacitance Cv=CL/m
Inductive reactance wLy<<1/aCv
Figure A2 Synthetic test circuit with inductive current circuit and voltage mutation regulating device In order to obtain voltage mutation, the circuit elements R., L. and C. must be connected between the circuit breaker under test and the ground. 6
Current circuit
Voltage U. =U./n
Current I. =I,
Inductive reactance L-1/n·oC
JB/T5871—1991
Breaking process
Voltage national road
Voltage U,=U.·2
Current ivO
Inductance Lr=1/C
Figure A3 provides a synthetic circuit for introducing voltage mutation·2
Current ivO
Inductance Lr=1/C
Figure A3 provides a synthetic circuit for introducing voltage mutation·2
Current ivO
Inductance Lr=1/C
Figure A3 provides a synthetic circuit for introducing voltage mutationAmplitude and waveform of closing surge current.
A4 Cut-off
Cut-off phenomenon caused by the interaction between the circuit breaker and the test circuit usually causes a reduction in the voltage on the load side, thereby reducing the dielectric load of the test product.
In the direct test circuit, when the capacitive test current is small, the possibility of cut-off is increased in the synthetic test circuit due to the following reasons;
Generally speaking, the characteristic parameters of the main components and the micro components of the test circuit are different, so the cut-off characteristics of the circuit breaker may change;
b. The influence of the auxiliary circuit breaker in series with the circuit breaker under test; c. The increase in the ratio of arc voltage to working voltage. Therefore, when conducting synthetic tests, it is difficult to determine whether cut-off is a significant feature of the circuit breaker. The following methods can be used to reduce the current. Change the capacitance seen from both ends of the circuit breaker; JB/T5871-—1991
Use a special auxiliary circuit breaker with a short minimum arcing time and low arc voltage. A5 Synthetic test circuit
A5.1 Basic circuit for breaking test
The synthetic test circuit consists of two circuits in principle, namely the current circuit and the voltage circuit. For capacitive current switching, both circuits can be capacitive. As long as the phase angle between the two power sources is changed accordingly. In some cases, an inductive or resistive current circuit can be used as an alternative.
The two power sources can be transformers fed by generators or charged capacitors, or a combination of the two. The synthetic circuit uses an auxiliary circuit breaker to isolate the circuit breaker under test from the current circuit. The connection between the two power sources and the two circuit breakers can be parallel (the voltage on the auxiliary circuit breaker is equal to the difference between the two power supply voltages) or series (the voltage on the circuit breaker under test is equal to the sum of the two power supply voltages). Depending on whether the voltage circuit is permanently connected or connected at a certain moment before or after the zero point of the power frequency current, it can be distinguished as a power frequency current feeding circuit, a current introduction circuit or a voltage introduction circuit. In the test under high power supply impedance conditions, the sudden voltage of the stock state is preferably generated by the current or voltage circuit at the end of the circuit breaker where the AC voltage is applied. The other end of the circuit-breaker must be loaded with a slowly decaying DC voltage. In some test circuits, two voltages are applied to one end of the circuit-breaker and the other end is grounded. This condition is more severe in terms of insulation to earth. For metal-enclosed circuit-breakers, an additional voltage source can be connected to the box to compensate for this effect. There are various circuits with different characteristics. Some examples are given in Figures A1 to A5. A5.2 Basic synthetic test circuit for making tests For capacitive synthetic making tests, the test voltage is applied by the voltage circuit from the moment the contacts close until the dielectric breakdown, followed by the initial state making current. For this purpose, some special components may be required. After the dielectric breakdown, the current circuit must be connected immediately to provide the transient making current and the subsequent power frequency current. For this purpose, the ball is ignited early to maintain the pre-breakdown current. In order to provide the required transient making current and power frequency current, a capacitive current source is suitable, while an inductive current source is not suitable because it does not give the correct current waveform. An example of a making circuit can be seen in Figure A6. Note: the formulas in Figures A1 to A6 are not accurate and only give approximate characteristics of the circuit. Symbols in Figures A1 to A6
a) Circuit schematic
b) Qualitative waveforms of current and voltage
c) Mathematical relationship between circuit parameters
The ratio of the specified test voltage U. to the actual voltage U. of the current circuit n
m—The ratio of the specified test current I, to the current of the voltage circuit u,—The voltage across the tested circuit breaker S.
Ux, U.—The voltage at each point A and B to ground
tai——Charging voltage of the voltage circuit
CL—Load capacitance
S.—Test product
S.—Auxiliary switch
Current circuit
Voltage U.=U./n
Current I=I (1-1/m)
Inductive reactance L<<1/C,
Capacitor C=n(1-
Line charging breaking current
JB/T5871
Breaking over
voltage circuit
voltage Uv=U.
Current Iv=IL/m
Inductive reactance WLv<<1/aC,
Capacitor Cv=Cz/m
Cr—load capacitance||tt ||Figure A1 Synthetic test circuit (parallel type)
The current circuit has a voltage U. and a capacitor C. to provide a capacitive current I. The voltage circuit provides the specified test voltage U and together with the capacitor C provides a smaller capacitive current I. 5
Current circuit
Voltage U.=-U./n
Current I. =I1-1/m)
Inductive reactance (L+L,)
n(1-1/m)wC,||tt| |JB/T5871—1991
Breaking process
Voltage circuit
Voltage U.=U.
Current IvI/m
Capacitance Cv=CL/m
Inductive reactance wLy<<1/aCv
Figure A2 Synthetic test circuit with inductive current circuit and voltage mutation regulating device In order to obtain voltage mutation, the circuit elements R., L. and C. must be connected between the circuit breaker under test and the ground. 6
Current circuit
Voltage U. =U./n
Current I. =I,
Inductive reactance L-1/n·oC
JB/T5871—1991
Breaking process
Voltage national road
Voltage U,=U.·2
Current ivO
Inductance Lr=1/C
Figure A3 provides a synthetic circuit for introducing voltage mutationAmplitude and waveform of closing surge current.
A4 Cut-off
Cut-off phenomenon caused by the interaction between the circuit breaker and the test circuit usually causes a reduction in the voltage on the load side, thereby reducing the dielectric load of the test product.
In the direct test circuit, when the capacitive test current is small, the possibility of cut-off is increased in the synthetic test circuit due to the following reasons;
Generally speaking, the characteristic parameters of the main components and the micro components of the test circuit are different, so the cut-off characteristics of the circuit breaker may change;
b. The influence of the auxiliary circuit breaker in series with the circuit breaker under test; c. The increase in the ratio of arc voltage to working voltage. Therefore, when conducting synthetic tests, it is difficult to determine whether cut-off is a significant feature of the circuit breaker. The following methods can be used to reduce the current. Change the capacitance seen from both ends of the circuit breaker; JB/T5871-—1991
Use a special auxiliary circuit breaker with a short minimum arcing time and low arc voltage. A5 Synthetic test circuit
A5.1 Basic circuit for breaking test
The synthetic test circuit consists of two circuits in principle, namely the current circuit and the voltage circuit. For capacitive current switching, both circuits can be capacitive. As long as the phase angle between the two power sources is changed accordingly. In some cases, an inductive or resistive current circuit can be used as an alternative.
The two power sources can be transformers fed by generators or charged capacitors, or a combination of the two. The synthetic circuit uses an auxiliary circuit breaker to isolate the circuit breaker under test from the current circuit. The connection between the two power sources and the two circuit breakers can be parallel (the voltage on the auxiliary circuit breaker is equal to the difference between the two power supply voltages) or series (the voltage on the circuit breaker under test is equal to the sum of the two power supply voltages). Depending on whether the voltage circuit is permanently connected or connected at a certain moment before or after the zero point of the power frequency current, it can be distinguished as a power frequency current feeding circuit, current introduction circuit or voltage introduction circuit. In the test under high power supply impedance conditions, the sudden voltage of the stock state is preferably generated by the current or voltage circuit at the end of the circuit breaker where the AC voltage is applied. The other end of the circuit-breaker must be loaded with a slowly decaying DC voltage. In some test circuits, two voltages are applied to one end of the circuit-breaker and the other end is grounded. This condition is more severe in terms of insulation to ground. For metal-enclosed circuit-breakers, an additional voltage source can be connected to the box to compensate for this effect. There are various circuits with different characteristics. Some examples are given in Figures A1 to A5. A5.2 Basic synthetic test circuit for making tests For capacitive synthetic making tests, the test voltage is applied by the voltage circuit from the moment the contacts close until the dielectric breakdown, followed by the initial state making current. For this purpose, some special components may be required. After the dielectric breakdown, the current circuit must be connected immediately to provide the transient making current and the subsequent power frequency current. For this purpose, the ball is ignited early to maintain the pre-breakdown current. In order to provide the required transient making current and power frequency current, a capacitive current source is suitable, while an inductive current source is not suitable because it does not give the correct current waveform. An example of a making circuit can be seen in Figure A6. Note: the formulas in Figures A1 to A6 are not accurate and only give approximate characteristics of the circuit. Symbols in Figures A1 to A6
a) Circuit schematic
b) Qualitative waveforms of current and voltage
c) Mathematical relationship between circuit parameters
The ratio of the specified test voltage U. to the actual voltage U. of the current circuit n
m—The ratio of the specified test current I, to the current of the voltage circuit u,—The voltage across the tested circuit breaker S.wwW.bzxz.Net
Ux, U.—The voltage at each point A and B to ground
tai——Charging voltage of the voltage circuit
CL—Load capacitance
S.—Test product
S.—Auxiliary switch
Current circuit
Voltage U.=U./n
Current I=I (1-1/m)
Inductive reactance L<<1/C,
Capacitor C=n(1-
Line charging breaking current
JB/T5871
Breaking over
voltage circuit
voltage Uv=U.
Current Iv=IL/m
Inductive reactance WLv<<1/aC,
Capacitor Cv=Cz/m
Cr—load capacitance||tt ||Figure A1 Synthetic test circuit (parallel type)
The current circuit has a voltage U. and a capacitor C. to provide a capacitive current I. The voltage circuit provides the specified test voltage U, and together with the capacitor C, provides a smaller capacitive current I. 5
Current circuit
Voltage U.=-U./n
Current I. =I1-1/m)
Inductive reactance (L+L,)
n(1-1/m)wC,||tt| |JB/T5871—1991
Breaking process
Voltage circuit
Voltage U.=U.
Current IvI/m
Capacitance Cv=CL/m
Inductive reactance wLy<<1/aCv
Figure A2 Synthetic test circuit with inductive current circuit and voltage mutation regulating device In order to obtain voltage mutation, the circuit elements R., L. and C. must be connected between the circuit breaker under test and the ground. 6
Current circuit
Voltage U. =U./n
Current I. =I,
Inductive reactance L-1/n·oC
JB/T5871—1991
Breaking process
Voltage national road
Voltage U,=U.·2
Current ivO
Inductance Lr=1/C
Figure A3 provides a synthetic circuit for introducing voltage mutation2 Basic synthetic test circuits for making tests For capacitive synthetic making tests, the test voltage is applied by the voltage circuit from the moment the contacts close until dielectric breakdown, followed by the supply of the initial state making current. For this purpose, some special components may be required. After dielectric breakdown, the current circuit must be connected immediately to provide the transient making current and the subsequent power frequency current. For this purpose, the ball should be ignited early in order to maintain the pre-breakdown current. In order to provide the required transient making current and power frequency current, a capacitive current source is suitable, while an inductive current source is not suitable because it does not give the correct current waveform. An example of a making circuit can be seen in Figure A6. Note that the formulas in Figures A1 to A6 are not accurate and only give approximate characteristics of the circuit. Symbols in Figures A1 to A6 a) Circuit schematic b) Qualitative waveforms of current and voltage c) Mathematical relationship between circuit parameters Specified test voltage U. and actual voltage U of the current circuit. The ratio n
m—a specified test current I, and the ratio u of the voltage loop current—the voltage across the tested circuit breaker S.
Ux, U.—the voltage at each point A and B. to ground
tai——the charging voltage of the voltage loop
CL—the load capacitance
S.—the test piece
S.—-the auxiliary switch
the current loop
voltage U.=U./n
current I=I (1-1/m)
Inductive reactance L<<1/C,
Capacitor C=n(1-
Line charging breaking current
JB/T5871
Breaking over
voltage circuit
voltage Uv=U.
Current Iv=IL/m
Inductive reactance WLv<<1/aC,
Capacitor Cv=Cz/m
Cr—load capacitance||tt ||Figure A1 Synthetic test circuit (parallel type)
The current circuit has a voltage U. and a capacitor C. to provide a capacitive current I. The voltage circuit provides the specified test voltage U, and together with the capacitor C, provides a smaller capacitive current I. 5
Current circuit
Voltage U.=-U./n
Current I. =I1-1/m)
Inductive reactance (L+L,)
n(1-1/m)wC,||tt| |JB/T5871—1991
Breaking process
Voltage circuit
Voltage U.=U.
Current IvI/m
Capacitance Cv=CL/m
Inductive reactance wLy<<1/aCv
Figure A2 Synthetic test circuit with inductive current circuit and voltage mutation regulating device In order to obtain voltage mutation, the circuit elements R., L. and C. must be connected between the circuit breaker under test and the ground. 6
Current circuit
Voltage U. =U./n
Current I. =I,
Inductive reactance L-1/n·oC
JB/T5871—1991
Breaking process
Voltage national road
Voltage U,=U.·2
Current ivO
Inductance Lr=1/C
Figure A3 provides a synthetic circuit for introducing voltage mutation2 Basic synthetic test circuits for making tests For capacitive synthetic making tests, the test voltage is applied by the voltage circuit from the moment the contacts close until dielectric breakdown, followed by the supply of the initial state making current. For this purpose, some special components may be required. After dielectric breakdown, the current circuit must be connected immediately to provide the transient making current and the subsequent power frequency current. For this purpose, the ball should be ignited early in order to maintain the pre-breakdown current. In order to provide the required transient making current and power frequency current, a capacitive current source is suitable, while an inductive current source is not suitable because it does not give the correct current waveform. An example of a making circuit can be seen in Figure A6. Note that the formulas in Figures A1 to A6 are not accurate and only give approximate characteristics of the circuit. Symbols in Figures A1 to A6 a) Circuit schematic b) Qualitative waveforms of current and voltage c) Mathematical relationship between circuit parameters Specified test voltage U. and actual voltage U of the current circuit. The ratio n
m—a specified test current I, and the ratio u of the voltage loop current—the voltage across the tested circuit breaker S.
Ux, U.—the voltage at each point A and B. to ground
tai——the charging voltage of the voltage loop
CL—the load capacitance
S.—the test piece
S.—-the auxiliary switch
the current loop
voltage U.=U./n
current I=I (1-1/m)
Inductive reactance L<<1/C,
Capacitor C=n(1-
Line charging breaking current
JB/T5871
Breaking over
voltage circuit
voltage Uv=U.
Current Iv=IL/m
Inductive reactance WLv<<1/aC,
Capacitor Cv=Cz/m
Cr—load capacitance||tt ||Figure A1 Synthetic test circuit (parallel type)
The current circuit has a voltage U. and a capacitor C. to provide a capacitive current I. The voltage circuit provides the specified test voltage U, and together with the capacitor C, provides a smaller capacitive current I. 5
Current circuit
Voltage U.=-U./n
Current I. =I1-1/m)
Inductive reactance (L+L,)
n(1-1/m)wC,||tt| |JB/T5871—1991
Breaking process
Voltage circuit
Voltage U.=U.
Current IvI/m
Capacitance Cv=CL/m
Inductive reactance wLy<<1/aCv
Figure A2 Synthetic test circuit with inductive current circuit and voltage mutation regulating device In order to obtain voltage mutation, the circuit elements R., L. and C. must be connected between the circuit breaker under test and the ground. 6
Current circuit
Voltage U. =U./n
Current I. =I,
Inductive reactance L-1/n·oC
JB/T5871—1991
Breaking process
Voltage national road
Voltage U,=U.·2
Current ivO
Inductance Lr=1/C
Figure A3 provides a synthetic circuit for introducing voltage mutation
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