Some standard content:
GB16926—1997
This standard is formulated based on the International Electrotechnical Commission IEC420:1990 publication "High Voltage AC Load Switch-Fuse Combination Appliances", and is equivalent to the international standard in terms of technical content. In this way, the technical content and writing rules of this standard are as consistent as possible with the corresponding international standards, so as to adapt to international trade, technical and economic exchanges as soon as possible and promote the development of such products. When this standard was formulated based on the international standard IEC 420, in order to suit my country's national conditions, some contents were slightly different from the international standard, such as voltage levels, environmental conditions, etc., but this does not prevent the overall and substantial equivalent adoption of the international standard. This standard specifies the following contents of AC three-pole load switch-fuse combination electrical appliances with rated voltage (i.e. maximum voltage) of 3.6~40.5kV and frequency of 50Hz, as well as their operating mechanisms and auxiliary equipment: - Scope;
Reference standards;
- Normal use conditions,
Definition;
Rated values;
Design and structure;
- Type test,
Factory test;
Information provided with inquiry, tender and order: - Rules for transportation, storage, installation and maintenance, - Appendix A: Guidelines for the use of load switch-fuse combination electrical appliances; Appendix B: Examples of coordination of fuses, load switches and transformers; Appendix C: Demonstration of methods for determining transfer current and (test) parameters related to test mode 4. Appendix A of this standard is an appendix to the standard. Appendix B and Appendix C of this standard are indicative appendices. This standard is proposed by the Ministry of Machinery Industry of the People's Republic of China: This standard is under the jurisdiction of the National High Voltage Switchgear Standardization Committee. This standard was drafted by Xi'an High Voltage Electric Apparatus Research Institute. The main chapter authors of this standard are Han Xiaoyong, Long Fuwei, Si Enwen, Sha Weihua, Hou Zhongqing, Liu Qingchun and Zhang Chongle. GB16926—1997
IEC Foreword
1. IEC formal resolutions or agreements on technical issues are proposed by technical committees representing all committees that are particularly concerned with these issues. They try their best to express the international consensus on the issues involved. 2. These resolutions or agreements are provided for international use in the form of recommended standards and are accepted by national committees. 3. In order to promote international unification, IEC hopes that all national committees will adopt the contents of IEC recommended standards as their national rules within the scope permitted by their national conditions. Any differences between IEC recommended standards and corresponding national rules should be clearly pointed out in the national rules as much as possible.
This standard was drafted by SC17A\High Voltage Switchgear and Controlgear Sub-Technical Committee\ under IECTC17\Switchgear and Controlgear Technical Committee\.
This second edition of EC Publication 420 replaces the first edition of 1973 and Amendments No. 1 (1973), No. 2 (1977) and No. 3 (1978).
This standard is based on the following documents
Six-month method
17A(CO)209
Voting report
17A(CO)212
Full information on the vote in favor of this standard can be found in the voting report indicated in the table above. 1 Scope 1
National Standard of the People's Republic of China
AC high-voltage load switch-fuse combinationsHigh-voltage alternatlng currentSwitch-fuse combinations
GB16926-1997
eqIEC420:1990
This standard applies to three-pole AC high-voltage load switch-fuse combinations (hereinafter referred to as combination appliances) used in power distribution systems with rated voltage (i.e. maximum voltage) of 3.6~40.5V and frequency of 50Haz. The main components of the combination appliance are AC high-voltage load switches (including isolating load switches) and current-limiting fuses. Each component shall comply with the provisions of its own standard in all relevant aspects. The purpose of installing a fuse is to expand the short-circuit rating of the combination appliance and make it exceed the short-circuit rating when the load switch is used alone. The installation of the striker is to rely on the action of the fuse to automatically separate the three poles of the load switch, and to enable correct operation when the fault current is less than the minimum breaking current of the fuse. In addition to the striker of the fuse, the combination device can also be equipped with an overcurrent release or a parallel release.
The combination device can break:
a) any load current up to the rated breaking current of the load switch b) any current up to the rated short-circuit breaking current of the combination device through overcurrent starting. This standard does not apply to fuse-breaker fuse-contactor combination devices in motor circuits or combination devices containing load switches that open and close a single capacitor bank. , Note
1 In addition to the operation through the fuse and its striker, automatic breaking can also be achieved through an overcurrent release or a self-protection device. 2 Considering the current limiting effect of the fuse, in addition to the short-time current and short-circuit closing requirements, the load switch should comply with GB3804-90. 3 If the combination device is equipped with an earthing switch, the earthing switch should comply with GB1985-89. 4 This standard also applies to load switch-fuse combination devices in ring network units. 2 Referenced standards 31
The following standards contain clauses that constitute standard clauses through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised. Parties using this standard should explore the possibility of using the latest versions of the following standards. GB 156-93 Standard voltage
GB311.1-1997 Insulation coordination of high-voltage transmission and transformation equipment GB/T16927.1 High voltage test technology Part 1: General test requirements GB762-83 Rated current of electrical equipment
Adoption instructions:
11IEC420:1990 1.1, the rated voltage range and frequency are above 1kV and below 52kV and 50Hz or 60Hz respectively. This standard is changed to 3.640.5kV and 50 Hz respectively according to the situation of my country's power system. 2] This standard puts the four "Notes" at the end of this chapter, and the arrangement is different from [IEC 420. 3] 1.2 in IEC 420, 1990. Most of the referenced standards listed in this standard have adopted IEC standards, but the degree of adoption is different. National Technical Supervision and Administration Commission Approved on July 28, 1997 and implemented on August 1, 1998
GB 169261997
GB76390 Heating of AC high-voltage electrical appliances during long-term operation GB 1094.1~1094.5-85 Power transformers GB1984-89 AC high-voltage circuit breakers
GB 1985-89 AC high-voltage isolating switches and earthing switches GB 2900.1—92 Basic terms of electrical engineering GB/T2900.19—94 Electrical terms High voltage test technology and insulation coordination GB/T2900.20—94 Electrical terms High voltage switchgear GB3309—89 Mechanical tests of high voltage switchgear at room temperature GB3804—90 3~63kV AC high voltage load switch GB3906—91 3~35kV AC metal enclosed switchgear GB5273—85 Terminals for transformers, high voltage electrical appliances and bushings GB7354—87 Partial discharge measurement
GB11022-89 General technical conditions for high voltage switchgear GB/T 15166.1—94 AC high voltage fuse terminology GB15166.2-94 AC high voltage fuse current limiting fuse GB/T15166.4-94 AC high voltage fuse general test method 3 Positive belt use conditions 1
According to Chapter 3 of GB1102289.
4 Definitions 2
In addition to the definitions adopted in this standard, the following terms are defined based on the characteristics of the combined electrical appliances. 4.1 Device device
4.1.1 Load switch-fuse combination electrical appliance switch-fuse combinations A combination electrical appliance, which includes a set of three-pole load switches and three fuses with strikers. Any action of the striker should automatically open all three poles of the load switch.
4.1.2 Load switch with fuse
switeh-fuse
A load switch, in which one or more poles are connected in series with the fuse in a composite unit. 4.1.3 Fuse-type load switch fuse-switch-A load switch, whose moving contact is composed of a fuse or a fuse-carrying fuse. 4.1.4 Release-operated combination A combination in which the automatic tripping of the load switch is triggered by an overcurrent release or a shunt release. Note: The release may be operated by an overcurrent relay or an earth-fault relay. 4.2 Characteristic parameters 4.2.1 Prospective-current (circuit and for the combination in it) The current flowing in the circuit if each pole in the combination is replaced by a conductor with negligible impedance. 4.2.2 Maximum prospective-peak current (AC circuit) The maximum prospective-peak current The peak current at the moment of maximum possible value. Instructions for use:
1] That is, Chapter 2 of IEC 420, 1990 According to the provisions of IEC 694, IEC694 stipulates that the lower limit of indoor temperature is -5°C, -25°C and the lower limit of outdoor temperature is -25°C, -40°C: the altitude is 1000m. GB11022-89 stipulates that the lower limit of indoor temperature is -10C, -25C/the lower limit of outdoor temperature is -30C, -40C, and the altitude is 1000, 2000, 3000 m. 2] That is, Chapter 3 of IEC420:1990. The provisions in the relevant national standards are no longer listed in this standard. GB169261997
Note: For multi-pole devices in multi-phase circuits, the maximum expected peak current refers to single phase only. 4.2.3 Prospective breaking current (for load switches or fuses) Prospective breaking current corresponds to the prospective current during the initial moment of the breaking process. Note: For mechanical switch devices or fuses, the initial moment of the breaking process is usually defined as the initial time of the arc during the breaking process. 4.2.4 Breaking current breaking current The current flowing through the load switch or fuse during the initial time of the arc during the breaking process. 4.2.5 Minimum breaking current minimum breaking current minimum value of the prospective current that the fuse can break under the specified conditions of use and performance and the specified voltage. 4.2.6 Short-circuit making capacity shart-circuit making capacity closing capacity under specified conditions (including short circuit of the switchgear terminals). 4.2.7 Transfer current (for combination devices operated by a striker) transfer current three-phase symmetrical current value when the fuse and the load switch switch switch the breaking function. When it is lower than this value, the first breaking current is broken by the fuse, and the subsequent two-phase current is broken by the load switch. When it is greater than this value, the three-phase current is only broken by the fuse. 4.2-8 Take-over current (for combination devices operated by a tripper) take-over current the current value corresponding to the intersection of the time-current characteristics of the two overcurrent protection devices (load switch and fuse). 4.2.9 Minimum take-over current (for trip-operated combination) This value is determined by the intersection of the time-current characteristics of the fuse and load switch corresponding to the following conditions: a) the maximum breaking time, if applicable, plus the maximum operating time of the external overcurrent relay or earth-fault relay; b) the minimum pre-arcing time of the fuse.
4.2.10 Maximum take-over current (for trip-operated combination) This value is determined by the intersection of the time-current characteristics of the fuse and load switch corresponding to the following conditions: a) the minimum interrupting time for the load switch to be actuated by the trip, if applicable, plus 0.029 to represent the minimum operating time of the external overcurrent relay or earth-fault relay; b) the maximum operating time of the fuse with the maximum rated current value. 4.2.11 Maximum acceptable power dissipation This value is determined by the temperature rise test to dissipate the power of the combination when the combination is fitted with a fuse of maximum power dissipation. 4.2.12 Fused short-circuit current The short-circuit current that is limited when the current limiting device is a fuse. 4.2.13 Applied voltage The voltage applied between the terminals of the load switch in the combination electrical appliance just before the load switch closes the current. 4.2.14 Recovery voltage recovery voltage The voltage that appears between the terminals of the load switch or fuse in the combination electrical appliance after the current is interrupted. 4.2.15 Transient recovery voltage (TRV) transient recovery voltage A recovery voltage with significant transient characteristics during the voltage recovery process. Note
The transient recovery voltage can be oscillating or non-oscillating or a combination of both, depending on the characteristics of the circuit and the load switch or fuse in the combination electrical appliance. It 1
includes the offset of the neutral point voltage of a multiphase circuit. 2 In a three-phase circuit, unless otherwise specified, the transient recovery voltage is the voltage on the first pole to be opened, which is higher than the voltage on any of the other two poles. 4.2.16 Power frequency recovery voltage The recovery voltage after the transient voltage phenomenon disappears. 4.2.17 Prospective transient recovery voltage (circuit) The transient recovery voltage that occurs after the prospective symmetrical current is interrupted by an ideal switching device. Note: To obtain the prospective transient recovery voltage, the ideal switching device that replaces the load switch or fuse is defined as: at the instant of the current spontaneous zero point, its resistance changes suddenly from zero to infinity. For a multiphase circuit, the current interruption by the ideal switching device only occurs at one pole under consideration. 4.2.18 Fuse-iniliated opening time (load switch) The time interval from the moment the fuse arcs to the moment all the pole arc contacts of the load switch are separated. 4.2.19 Release-initiated opening time (load switch) The release-initiated opening time of the release is defined according to the following tripping method, when any delay device forming an integral part of the load switch is adjusted to the specified setting value. bzxZ.net
a) For load switches whose tripping power is provided by any form of auxiliary power supply, the release-initiated opening time is the time interval from the moment the opening release of the load switch in the closed position is energized to the moment all the pole contacts are separated. b) For load switches that are tripped by the current in the main circuit rather than by any form of auxiliary power supply (except those triggered by impactors): the release time triggered by the release is the time interval from the moment when the main circuit current of the load switch in the closed position reaches the overcurrent release action value to the time when all pole arc contacts are separated. 4.2.20 Minimum release-initiated opening time triggered by the release (load switch) minimum release-initiated opening time The release time triggered by the release when the setting value of any delay device integrated with the load switch is the minimum of its specified value. 4-2.21 Maximum release-initiated opening time triggered by the release (load switch) maxirnum release-initiated opening time The release time triggered by the release when the setting value of any delay device integrated with the load switch is the maximum of its value. 4.2.22 Breaking time (of the load switch in the combination electrical appliance operated by the release ）breakingtime The time interval from the moment of the load switch breaking time triggered by the tripper to the moment when all the pole arcs are finally extinguished. Note: According to the breaking time and arcing time adopted, the term can be qualified by adding "maximum" or "minimum" in front of it. 5 Rated value
5.7 Rated voltage (i.e. maximum voltage)2
Rated voltage According to the provisions of GB156, the maximum voltage of the electrical equipment is selected, see Table 1. Table 1 AC high-voltage load switch-fuse combination electrical appliance Rated voltage frequency Rated voltage
12(11.5)m
1) The values in brackets are applicable to tests of old products and test stations that cannot meet the specified values of the recovery voltage. 2) The values in brackets are used when the user requires it. 5.2 Rated insulation level3
(2432)
According to the provisions of GB311.1 and GB11022, the rated insulation level of the combination electrical appliance should be selected from Table 2. 5.3 Rated frequency
5.4 Rated current
The rated current value shall be selected from the following values:\kv
1.6,3.15,6.3,8,10.12-5,16,20.25,31.5,40,50,63,80,100,125,160,200.250,315,400A Note
1 The rated current is for the complete combination of load switch and selected fuse. 2 When the rated value of the fuse installed in the combination is different from the rated value of the fuse used in the temperature rise test, the rated current of the combination shall be changed. Note:
11 That is, Chapter 4 of [EC 120:1990. 27 That is, 4.1 of [EC420:1990, the rated voltage is specified to be below 52kV. my country's power system only has the values in Table 1, and there is no 17.5 and 36kV level. 3］ That is, 4.2 of IEC420:1990 is in accordance with the provisions of IEC694. The absolute explosion level specified in Table 2 of this standard is in accordance with GB311.1. The 1mIm power frequency withstand voltage is higher than the provisions of 1EC694.
47 That is, 4. 4.1 of IEC.420,1990 is in accordance with the provisions of IEC 694. This standard gives specific values. ww.bzsoso:comGB169261997
value. For any specific case, the rated current of the load switch-fuse combination shall be as specified by the combination manufacturer. For detailed information, see Appendix A.
Table 2 Rated insulation level of AC high-voltage load switch-fuse combination Rated lightning impulse withstand voltage (bee value)
Rated voltage
To ground, between phases and common break
Series 1
Series 1
Series 1
Rated short-time (1 min) power frequency withstand voltage
To ground, between phases and common break
Series 1\
Series 12
Series 11
1) The continuity level of Series I of the combination corresponding to the rated voltage of 3.6~12 kV is only applicable to the neutral point directly grounded system. 2) The value under the slash line in this column is the withstand voltage of the internal and external insulation of the plastic combined electrical appliance in the dry state. 5.5 Temperature rise
shall be in accordance with the provisions of GB 763, and for fuses, in accordance with the provisions of GB 15166.2. 5.6 The rated power supply voltage of the closing and opening mechanisms and auxiliary circuits shall be in accordance with the provisions of 5.8 in GB11022--89. 5.7 The rated gas pressure of the operating gas source
shall be in accordance with the provisions of 5.9 in GB 11022. 5.8 Rated short-circuit breaking current 2
Series 2)
88/105
The rated short-circuit breaking current refers to the maximum expected short-circuit current that the combined electrical appliance can break under the conditions of use and performance specified in this standard. For the expected short-circuit current, see the note after 5.10. The rated short-circuit breaking current is expressed as the effective value of its AC component. The rated short-circuit breaking current shall be selected from the following values: 6.3, 8, 10, 12.5, 16, 20, 25, 31.5, 40, 50, 63, 80, 100 kA.5.9 Rated transient recovery voltage (TRV)
The rated transient recovery voltage corresponding to the rated short-circuit breaking current (according to 5.8) is a reference voltage. It is the upper limit of the circuit expected to be broken under the short-circuit fault condition of the circuit that the combined electrical equipment should be able to break. Table 3 gives the standard values of the rated break-off recovery voltage of the power supply circuit of test mode 1. The expected transient recovery voltage is often in the form of attenuation, single-frequency oscillation, or something similar to it. This waveform can be represented by an envelope consisting of two sections defined by two parameters (see Figure 1). Adoption instructions:
1] That is, 4.101 of IEC 420:1990. This standard supplements the 6.3 kA level. 2] That is, the TRV values of 17.5 kV and 36 kV in Table 1 of 4.102 of IEC 420:1990 were not adopted, which is not in line with national conditions. Table 3 of this standard supplements the TRV value of 40.5 kV.
Rated positive
First parallel pole coefficient
u,-K-.K,.
GB16926—1997
Table 3 Expected transient recovery voltage specified values expressed by two parameters for rated voltages of 40.5kV and below
TRV peak value
Time coordinate
Labi uu sound
e+—0.15t
Note: The values in brackets are used when required by the user. 5.10 Rated short-circuit making current
Voltage coordinate
Time coordinate
Rise rate
kV/μs
The rated short-circuit making current is the maximum expected peak current that the combination electrical appliance can make under the use and performance conditions specified in this standard. It should be 2.5 times the rated short-circuit breaking current. Note that the series impedance of the combined appliance, the rapid action of the fuse or the load switch may produce one or both of the following effects: a) the short-circuit current is reduced to a value that is significantly lower than the value that can be achieved without the above effects, and b) rapid breaking will cause the waveform of the short-circuit current to deviate from its normal waveform. This is why the term "expected current" is used at any time to evaluate the breaking and closing performance. 5.11 The three-phase symmetrical current value in the test circuit used in the rated transfer current (striker operation) test method 4. Note: In test method 4, the current actually interrupted by the load switch is a two-phase current, and its current value is at least equal to 3/2 (i.e. B7%) times the rated transfer current, and the other phase is flashed by the fuse and disconnected or open. 5.12 The three-phase symmetrical current value in the test circuit used in the rated transfer current (tripper operation) test method 5. 6 Design and structure
6.1 The requirements for liquid in the load switch-fuse combination electrical appliance shall comply with the provisions of 6.1 in GB 11022-89. 6.2 The requirements for gas in the load switch-fuse combination electrical appliance shall comply with the provisions of 6.2 in GB 11022-89. 6.3 The grounding of the load switch-fuse combination electrical appliance shall comply with the provisions of GB 6.4 Auxiliary equipment
According to the provisions of 6.6 in GB 11022-89. 6.5 Power closing
According to the provisions of 6.8.1 in GB11022-89. 6.6 Energy storage closing
According to the provisions of 6.8.2 in GB11022-89. 6.7 Trip operation
According to the provisions of 6.9 in GB11022-89.
6.8 Low pressure and high pressure locking devices
According to the provisions of 6.10 in GB 11022--89. 6.9 Nameplate
GB 16926-1997
According to the provisions of 6.13 in GB 11022-89. In addition to the provisions of the load switch-fuse combination, the nameplate of the load switch-fuse combination shall also include the contents listed in Table 4. Table 4 Nameplate marking
Item name
Manufacturer
No. of the adopted standard
Rated voltage
Rated lightning strike withstand voltage
Rated power frequency withstand voltage
Rated short-circuit breaking current
Maximum rated current of the fuse
Strike type (output energy)
Rated exchange gas pressure
Rated power supply voltage of the auxiliary circuit
Manufacturing year and month
Temperature level
Medium or heavy
Load switch-fuse combination
Table: x - a value that must be marked, A blank space indicates that the value is zero. The value to be marked depends on the conditions in column 6. Operating
condition, only when the combination device is not an integral
or the manufacturer is different, it is necessary to mark
When applicable
When applicable
Different from 10℃ (indoor)
Different from -25℃ (outdoor)
To: The symbols in column (2) can be used instead of the names in column (1). When the names in column (1) are used, the word "rated" can be omitted. 6.10 Combinations
Load switch-fuse combinations shall be designed to be able to interrupt any current value up to the rated short-circuit breaking current at the specified recovery voltage.
The load switch-fuse combination device can close the circuit with rated short-circuit breaking current at rated voltage. 6.11 Load switches used only in combination devices. The load switches used in combination devices shall meet the following test requirements. The mechanical life test shall comply with the provisions of 6.6.3 of GB3804-90. The breaking test methods 1, 3 and 4 shall comply with 6.5. The short-circuit closing test shall comply with the provisions of 6.12 of this standard. The active load breaking capacity of the load switch shall be equal to or greater than the maximum rated current of the combination device. Note: The special load switch in the combination device does not need to meet the requirements of short-time withstand current. Adoption instructions:
1] That is, [5.9 of IEC420:1990 and the corresponding Table I. In Table 4 of this standard, the items "rated frequency", "fuse model and manufacture" and so on are omitted, and the items "number of the adopted standard", "rated power frequency withstand voltage" and "rated short-circuit breaking current" are added. 2] Different from the provisions in Table 1 of IEC 420:1990, this standard re-defines the temperature value to adapt to my country's national conditions. 6.12 Short-circuit closing current of load switch
GB16926-1997
The load switch should be able to close the maximum cut-off current of the fuse that may be used in the combination device. 6.13 Linkage between fuse striker and load switch release The linkage between fuse striker and load switch release should enable the load switch to operate well under both three-phase and single-phase conditions, under the maximum and minimum energy of a given striker model (medium or heavy) and the action mode of the corresponding striker (spring-type or explosion type).
6.14 Interlocking of grounding switch 1
When a grounding switch is installed, the interlocking between the grounding switch and the isolating load switch should meet the requirements of GB1985-89. 6.15 Position indicator
When a position indicating device is installed, the indicating device should be able to correctly indicate the open or closed position of the load switch. Note: See the provisions of 5.3.8.2 in GB 3804-90. 7 Type test
The type test items and requirements of load switch-fuse combination electrical appliances shall comply with the relevant provisions of GB11022-89 and make the following supplements:
It should be clearly pointed out that before the combination electrical appliance undergoes type test, the load switch in the combination electrical appliance shall undergo type test of relevant items in accordance with GB3804-90; the fuse in the combination electrical appliance shall undergo type test in accordance with GB 15166.2-94. Type test items:
a) Insulation test:
b) Temperature rise test;
c) Main circuit resistance measurement:
d) Short-time withstand current and peak withstand current test;
e) Closing and breaking test,
f) Test on the mechanism.
The test product provided shall meet the following conditions:
a) The test product shall be consistent with the product drawings and technical documents; b) When the release operation mode is used, an overcurrent relay or release shall be installed, and its minimum current rating shall match the selected fuse.
c) The test product shall be new and equipped with a fuse that meets the requirements of the combination electrical appliance. The test product shall be fully assembled according to the design requirements (such as filling with specified pressure, specified type and number of liquids and gases, etc.; equipped with specified types of operating mechanisms or auxiliary equipment, etc.). In the following cases, the combination electrical appliances shall be subjected to type tests: 3a) New trial products shall be subjected to all type tests: b) Products that are transferred to trial production shall be subjected to all type tests: c) When the model or specification of the load switch or fuse, operating mechanism or auxiliary equipment used by the combination electrical appliances is changed, the type test of the corresponding items shall be carried out;
d) When the product is significantly changed in design, process or materials used, the type test of the corresponding items shall be carried out: e) When mass-produced products are produced every 8 to 10 years or infrequently produced products (referring to those that stop production for 5 years or more) are produced again, all items of type tests shall be carried out. Instructions for use:
1] IEC420:1990 does not specify this item. Considering that the grounding switch may be a component of the load switch, this standard makes supplementary provisions. 21 In order to facilitate the understanding of the content of the type test and facilitate the implementation of the standard, this standard adds type test items\. 37IEC420:1990 Technical provisions, according to my country's needs for high-voltage switchgear type test management, this standard has been supplemented. GE16926-1997
All type test results should be issued in a formal type test report. The type test report should include sufficient information to prove that the test product complies with this standard and related standards, and should also include technical documents and drawings that the test product should comply with. The type test report should also include relevant information on the main combination components, operating mechanisms or auxiliary equipment of the test product, structural conditions and installation methods. The manufacturer is only responsible for the specified values, but not for the data obtained in the type test that exceeds the specified value range. 7.1 Insulation test
The insulation test shall be carried out according to the withstand voltage values specified in 7.1 of GB 11022-89 and 5.2 of this standard. In addition, the combination electrical appliances with gas-filled compartments shall also be subjected to the rated voltage withstand test of the gas-filled compartment zero gauge pressure for 5 minutes according to 7.1.9 of GB 3906-91. 11 When there are partial discharge test requirements for components in the combination device, partial discharge test should be carried out. The partial discharge test can be carried out on components or parts in accordance with the provisions of GB7354-87, and the allowable discharge amount is specified by other relevant standard product technical documents. During the insulation test, it should be carried out on the combination device where the arrangement of components can provide the most unfavorable insulation conditions. If it cannot be proved, the test should be carried out under various possible arrangement schemes.
7.2 Temperature rise test
The temperature rise test is carried out in accordance with the provisions of 7.3 of GB 11022-89 and relevant standards. During the test, the combination device should be installed with a fuse with the maximum current rating and/or maximum power dissipation. The test current is the rated current value of the load switch-fuse combination device. After the test, the temperature rise of the fuse should comply with the provisions of GB15166.2-94, and the temperature rise of its components and parts should comply with the provisions of GB11022-89. During the test, the following information of the fuse used shall be recorded: a) manufacturer and model:
b) rated voltage,
c) rated current:
d) DC resistance 1
e) power dissipation.
When the fuse is used under poor heat dissipation conditions, the rated value can be reduced. In order to meet the derating value, a special test can be carried out to determine the power dissipation.
These tests shall be carried out under the conditions specified in the temperature rise test. The power dissipation shall be determined when the voltage under consideration reaches a stable value. The test shall be carried out at 50% and 100% of the rated current. The power dissipation is expressed in W.
The power dissipation value measured at the end of the temperature rise test is the maximum power dissipation value acceptable to the combination electrical appliance. 7.3 Main circuit resistance measurement
The main circuit resistance measurement shall be carried out in accordance with the provisions of 7.4 of GB11022-89, and its resistance value shall be specified by the product technical conditions. When the influence of the inherent resistance dispersion of the fuse on the characterization of the loop resistance is eliminated, the DC resistance can be measured after replacing the fuse with a conductive rod with negligible impedance. At this time, the DC resistance of the conductive rod should be recorded. 7.4 Short-time withstand current and peak withstand current test Short-time withstand current and peak withstand current test are not applicable to load switch-fuse combination electrical appliances. However, considering other functional units or branches of the combination electrical appliances (such as grounding switches, grounding loops, etc.), when short-time withstand current and peak withstand current tests are required, they shall be carried out in accordance with 7.5 of GB11022-89 or other relevant standards. 7.5 Closing and breaking test
7.5.1 General
Instructions for use:
1]IEC420 has no corresponding provisions. According to user requirements, this standard adds the content of the sentence after this paragraph. 2]1EC420:1990 uses \Note\ as a reminder, and this standard adds supplementary instructions based on \Note\ as the main text. 3. "1EC420:1990 only explicitly states that it is not applicable." This standard makes specific provisions for certain special cases. GB169261997
The closing and breaking tests specified in this standard are to test and assess the ability and coordination performance of the load switch-fuse combination device to close and break various fault currents.
Since this standard is applicable to three-pole combination devices used in three-phase power systems, any test method is based on the principle of three-phase circuits. 7.5.2 Condition of combination devices before the test
Before the test, the combination device shall meet the general conditions mentioned in Chapter 7 of this standard and the following requirements: a) The combination device under test shall be completely installed on its own bracket or equivalent bracket. b) Its equipped operating mechanism shall be operated in accordance with relevant regulations. If the operating mechanism is a manual or pneumatic operation mode, it shall be operated at the minimum voltage or air pressure specified in 6.8 and 6.9 of GB1311022-89 respectively. If the cut-off affects the test results, the combination device is allowed to be operated at GB 11022-89, 6.8 and 6.9 Operate at a voltage or pressure selected within the specified tolerance range so that the maximum separation speed and maximum arc extinguishing performance are obtained at the moment of contact separation. It should be shown that the combined electrical appliance can reliably perform air-cutting operation under the above conditions. If possible, the travel of the moving contact should be recorded. If it is a combined electrical appliance operated by manual energy storage, it can be remotely operated by a certain device. c) When the actual layout of the power supply side and the load side of the combined electrical appliance are different, and the combined electrical appliance has the possibility of power supply from both sides, the live side of the test circuit should be connected to the side that makes the test conditions of the combined electrical appliance more severe. If there is any doubt about this, the power supply connection should be reversed and the test should be repeated. However, for the test mode that includes the same test in the next two times, the power supply should be connected to one side first, and a test should be carried out, and then the power supply should be connected to the other side for the remaining tests.
d) The combined electrical appliance should be tested with a fuse of the maximum rated current and/or maximum operating value specified by the manufacturer for the combined electrical appliance.
e) For combined electrical appliances equipped with trip operation, the overcurrent relay or trip shall match the minimum current rating of the fuse used.
f) Unless otherwise specified, the test shall be carried out at normal ambient temperature without preloading of the combined electrical appliances. 7.5.3 Test circuit
7.5.3.1 Test frequency
The test circuit frequency deviation shall be ±10% of the rated frequency. 7.5.3.2 Power factor
The test circuit power factor shall be determined by calculating or measuring the circuit decay time constant and taking the average value of the three-phase power factor. During the test, the three-phase average value of the test circuit power factor shall comply with the provisions of 7.5.G.1 to 7.5.5.5 of this standard. 7.5.3.3 Arrangement of the test circuit
For test mode 1 and test mode 2, the combined electrical appliance is preferably a circuit with an insulated neutral point of the power supply, and the two phases of the combined electrical appliance outlet terminal are short-circuited and the neutral point is grounded, as shown in Figure 3a. When the neutral point of the power supply of the test circuit cannot be insulated, it should be grounded: the neutral point of the three-phase short-circuit at the outlet of the combination electrical appliance should be insulated, as shown in Figure 3b. For test method 3, the combination electrical appliance should be connected to a single-phase circuit, and only the neutral point of the power supply or the neutral point of the test product is allowed to be grounded, as shown in Figures 4a and 4b. The power supply neutral point grounding method is the preferred method. For test methods 4 and 5, the combination electrical appliance should be connected to the circuit shown in Figures 5a and 5b. Among them, the load neutral point grounding method is the preferred method.
For combination electrical appliances that may produce flames or metal particle spraying, a metal screen should be installed near the live conductor during the test, and the size of the interval between the metal screen and the live conductor should be specified by the manufacturer. The metal screen, chassis and other normally grounded parts should be insulated from the ground, but grounded through a suitable arm indicating the leakage current to the ground. 7.5.4 Closing and breaking test parameters
7.5.4.1 Test voltage for breaking test
The test voltage should be measured immediately at the location of the switchgear after it is disconnected, and it should be the average value of the line voltage. The test voltage measurement point should be as close to the switchgear terminal as possible, that is, there is no obvious impedance between the measurement point and the switchgear terminal. In three-phase test, the test voltage should be as equal to the rated voltage of the switchgear as possible. ww.bzsoso:com
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