Some standard content:
National Standard of the People's Republic of China
335kV AC metal-enclosed switchgear
ACmetal-enclosed switchgear for rated voltages of 3~35kV
GB3906-91
replaces GB3906—83|| tt||This standard refers to the international standard IEC298 (1990) "AC metal-enclosed switchgear and control equipment above 1kV and 52kV and below".
1 Subject content and scope of application
This standard specifies the requirements for use conditions, ratings, design and structure, type testing and factory testing of metal-enclosed switchgear.
This standard applies to metal-enclosed switchgear with rated voltage 3~35kV, frequency 50Hz, indoor or outdoor. This standard applies to metal-enclosed switchgear with atmosphere as insulation (including composite insulation). It also applies to metal-enclosed switchgear with a design pressure of the inflatable compartment not exceeding 0.3MPa (gauge pressure); for metal-enclosed switchgear with a design pressure exceeding 0.3MPa (gauge pressure) Gauge pressure) inflatable compartments shall be designed and tested in accordance with the provisions of GB7674; for metal-enclosed switchgear above 35kV and below 63kV that is insulated by the atmosphere and the design pressure of the inflatable compartment does not exceed 0.3MPa (gauge pressure), it may Implement with reference to this standard. Special-purpose metal-enclosed switchgear, in addition to complying with the provisions of this standard, special requirements items shall be negotiated between the user and the manufacturer. 2 Reference standards
GB762 Rated current of electrical equipment
GB763 Heat generation of AC high-voltage electrical appliances during long-term operation GB1408. Power frequency electrical strength test method for solid insulating materials GB1984
AC high-voltage circuit breaker| | tt |
GB7354
Mechanical test partial discharge measurement of high-voltage switchgear at normal temperature
GB7674
Sulfur hexafluoride closed combined electrical appliances
GB11022||tt ||GB11023
3 terms
General technical conditions for high-voltage switchgear
Guidelines for sulfur hexafluoride gas sealing test for high-voltage switchgear. In addition to the provisions in 19, the following supplements are made: 3.1 Metal-enclosed switchgear
Switchgear that is completely enclosed by a grounded metal shell, except for the incoming and outgoing wires. Note: There are three types of metal-enclosed switchgear; armored metal-enclosed switchgear;
State Bureau of Technical Supervision approved on 1991-12-14 and implemented on 1992-06-01
interval type metal-enclosed switch Equipment;
Box-type metal enclosed switchgear.
3.1.1 Armored metal-enclosed switchgear
GB3906-91
Metal with certain components installed in grounded compartments separated by metal partitions Enclosed switchgear. Note: The metal partition should comply with the protection level specified in Table 6 of Article 6.12 of GB11022. There should be separate compartments for at least the following components: a. One main switch for each;
b. One side of the connection to the main switch components, such as feed lines; c. Connect to components on the other side of the main switch, such as the busbar. If there are more than one set of busbars, each set of busbars should be located in separate compartments. 3.1.2 Spaced metal-enclosed switchgear (with non-metallic partitions) Spaced metal-enclosed switchgear is the same as armored metal-enclosed switchgear. Some of its components are also located in separate compartments, but have a or multiple non-metallic partitions. The protection level of the partitions should comply with the provisions of Table 6 of Article 6.12 of GB11022. 3.1.3 Box-type metal-enclosed switchgear
Metal-enclosed switchgear other than armored and spaced metal-enclosed switchgear. Note: It applies to switchgear with metal housing and with the following conditions: a. The number of compartments is less than that of armored and compartmented metal-enclosed switchgear; b. The protection level of the partitions is lower than the requirements in Table 6 of Article 6.12 of GB11022; c. There are no partitions.
3.2 Transport unit
A part of a metal-enclosed switchgear suitable for transportation without disassembly. 3.3 Functional unit
The functional unit is part of the metal-enclosed switchgear. It includes all main circuit and other circuit components that jointly complete a function.
Note: Functional units can be distinguished according to predetermined functions, such as incoming line units, feedout units, etc. 3.4 Shell
The shell is part of the metal-enclosed switchgear. Under the specified protection level, it protects the internal equipment from the outside world and prevents the human body and foreign objects from approaching the live parts and touching the moving parts. 3.5 Compartment
A part of a metal-enclosed switchgear that is closed except for openings necessary for interconnection, control or ventilation. Note: ① The compartments can be named after the main components inside, such as circuit breaker compartment, busbar compartment, etc. ② The openings necessary for interconnection between compartments should be closed with sleeves or similar means. ③Busbar compartments can be connected through functional units without using casings or other similar measures. 3.6 Inflatable compartment
A compartment of metal-enclosed switchgear that has one of the following systems (see Appendix C) to maintain gas pressure: a. Controlled pressure system;
b. Closed pressure system;
c. Sealed pressure system
Note: Several gas-filled compartments can be interconnected to a common gas system (gas-tight assembly). 3.7 Components
Main components that perform specified functions in the main circuit and grounding circuit of metal-enclosed switchgear (such as circuit breakers, load switches, contactors, isolating switches, grounding switches, fuses, transformers, bushings , busbar, etc.). 3.8 Partition
Part of a metal-enclosed switchgear which separates one compartment from another. 3.9 Flap
Part of a metal-enclosed switchgear having two switchable positions. In the open position, it allows the movable contact of the removable part to be inserted into the GB3906-91
static contact; in the closed position, it becomes part of the partition or shell, covering the static contact. 3.10 Bushing
It is a structure with one or more conductors passing through the shell or partition and insulating the conductor from the shell or partition, including its fixed accessories.
3.11 Removable parts
Parts that can be completely removed from the metal-enclosed switchgear and can be replaced, even when the main circuit is live. 3.12 Pull-out parts
It is also a removable part. It can be moved to form an isolating break or separation between the separated contacts, while still maintaining mechanical contact with the housing.
3.13 Separation
An arrangement of conductors in which a grounded metal plate is inserted between the conductors so that destructive discharges can only occur between the conductors and the ground.
Separation can be established between conductors or between contacts of the same pole of the switch. 3.14 Working position (switched on position)
In order to complete the intended function, the removable parts are in full contact position. 3.15 Grounding position
A position of removable components. In this position, the grounding switch can be operated to short-circuit the main circuit and ground it. 3.16 Test position (with extractable components) A position in which components can be extracted. In this position, the main circuit forms an isolation break or separation. The control circuit is connected. 3.17 Disconnected position (of extractable components) A position in which components can be withdrawn. In this position, the main circuit forms an isolation break or separation and maintains mechanical contact with the housing (the auxiliary circuit does not need to be disconnected).
3.18 Removable position (of a removable component) A position of a removable component. The removable part is outside the housing and is disconnected mechanically and electrically from the housing. 3.19 Main circuit
All conductive parts used to transmit electrical energy in metal-enclosed switchgear. Note: The connecting wire connected to the voltage transformer is not considered as the main circuit. 3.20 Auxiliary circuit
The conductive part of all control, measurement, signal and regulation circuits in metal-enclosed switchgear except the main circuit. Note: The auxiliary circuit of metal-enclosed switchgear includes the auxiliary circuit of the switch. 3.21 Rating value
The rating value referred to in this standard is the parameter value given by the metal-enclosed switchgear under the specified working conditions, which is generally provided by the manufacturer.
3.22 Protection level
The degree of protection of the casing, partitions and other parts to prevent the human body from approaching live parts and touching moving parts and from external objects intruding into internal equipment.
3.23 Destructive discharge
A discharge accompanied by insulation damage under the action of an electric field. During discharge, the arc crosses the insulating medium and the voltage between the electrodes drops to zero or close to zero.
Note: ① This term applies to discharges of solid, liquid and gaseous media and their combinations. ② Destructive discharge causes the solid medium to permanently lose its insulation strength (non-recovery insulation), while in liquid and gas media, the loss of insulation strength is only temporary (self-recovery insulation).
③ "Spark discharge" refers to the destructive discharge that occurs in gas or liquid media. GB3906-91
"Flashover" refers to the destructive discharge occurring on the surface of a solid medium in a gas or liquid. "Breakdown" refers to a destructive discharge through a solid medium. 3.24 Design pressure (of the inflatable compartment)
is expressed in MPa (gauge pressure) and is used to determine the design pressure of the inflatable compartment. 3.25 Design temperature (of the gas-filled compartment)
The highest temperature that the gas can reach under normal operating conditions. 4Normal use conditions
Normal use conditions are in accordance with Chapter 3 of GB11022. For additional requirements for 3~35kV AC metal-enclosed switchgear under severe conditions, this standard makes corresponding provisions in Appendix E. 5 Ratings
The ratings adopted in this standard, in addition to the provisions of Chapter 5 of GB11022, are supplemented as follows: 5.1 Rated current (of functional units)
Within each functional unit, each The value of the component with the smallest rated current among the main circuit components is the rated current of the functional unit. Its value is selected from the specified values ??in GB762.
5.2 Rated current of the main bus
The maximum rated current that the main bus can pass. Its value is selected from the specified values ??in GB762. 5.3 Rated thermal stable current (of functional unit) In a functional unit, the value of the component with the smallest rated thermal stable current among the components of the main circuit is the rated thermal stable current of the functional unit. Its value is selected from the values ??specified in Article 5.5 of GB11022. 5.4 Rated dynamic and thermal stable current values ??of the ground loop. The rated dynamic and thermal stable current values ??of the ground conductor, ground connection, grounding device and the ground loop should be coordinated with the main circuit parameters, or negotiated between the user and the manufacturer.
5.5 rated short-circuit breaking current
3.15,4.0,5.0,6.3,8.0,10,12.5,16,20,25,31.5,40,50kA. 5.6 Rated closing current
8,10,12.5,16,20,25,31.5,40,50,63,80,100,125kA. 5.7 The rated inflation pressure (for the inflatable compartment) is the pressure value specified by the manufacturer relative to the temperature of 20°C and the atmospheric pressure of 0.1013MPa, expressed in MPa (gauge pressure). This pressure value is specified by the product technical conditions.
6 Design and Structure
The design of metal-enclosed switchgear should enable normal operation, monitoring and maintenance to be carried out safely and conveniently. Maintenance work includes: component inspection, testing, fault finding and handling. Components with the same rated parameters and structure that need to be replaced should be interchangeable. Metal-enclosed switchgear with removable parts shall be interchangeable if the removable parts have the same ratings and construction. If removable parts have several ratings and are interchangeable in metal-enclosed switchgear, then any combination of removable parts and fixed parts shall have the rated insulation level of the fixed part of the equipment. In addition to the components installed in the enclosure should comply with their respective standards, the following factors should be taken into consideration in the design of metal-enclosed switchgear:
a. The casing should have sufficient mechanical strength so that the switches, operating mechanisms and other components installed in the casing have their original mechanical and electrical properties.
GB3906-91
b. If an oil-immersed transformer and other similar components are installed in the casing, it should not affect adjacent equipment when a fault occurs, and it should also be easy to inspect and inspect during operation.
6.1 Shell
6.1.1 General
The shell must be made of metal (except for ventilation windows and exhaust ports) and must not be made of mesh braid or similar materials. The shell must It meets a protection level specified in Table 6 of Article 6.12 of GB11022 and complies with the following conditions to ensure its protective performance. Although the surface of the floor is not made of metal, it can also be used as part of the enclosure. However, if there is a cable trench connected or a cable entering, it must be closed, and it should meet a protection level specified in Table 6 of Article 6.12 of GB11022. The walls of the house cannot be part of the enclosure. Inflatable compartments should be able to withstand normal and transient pressures encountered in use. These compartments are subject to continuous pressure in use. These different conditions are different from containers of compressed air and similar pressure vessels. Yes: a. The inflatable compartment closes the main circuit, not only preventing access to live and moving parts, but also structurally requiring a rated insulation level at (or above) the minimum functional pressure (when determining its shape and selecting materials, priority is given to electrical performance and not mechanical properties). b. The gas-filled compartment is usually filled with dry, stable, inert, non-corrosive gas. In order to ensure reliable operation of the switchgear, measures have been taken so that gases meeting the above conditions have only small pressure fluctuations. And because the inner wall of the compartment will not suffer from corrosion. Therefore, these factors need to be considered when determining the design of the compartment. www.bzxz.net
c. The pressure during operation is relatively low. For outdoor metal-enclosed switchgear, the influence of climate conditions should be taken into consideration when designing. 6.1.2 Design of the inflatable compartment
The inflatable compartment shall be designed according to the design temperature and design pressure defined in this standard. The design temperature of a gas-filled compartment is the upper limit of the ambient air temperature plus the temperature rise of the gas when the rated current flows through it. If solar radiation has a significant effect, this should also be considered.
The calculation method of the thickness and structure of the shell can be selected according to the pressure vessel design regulations. The design pressure of the shell should be at least the upper limit of the pressure that can occur in the shell at the design temperature. Also consider the following issues:
The highest possible pressure difference on either side of the compartment wall or partition, including possible evacuation processes using aeration processes; a.
With different operating pressures Pressure caused by accidental leakage between adjacent compartments; b.
c. Possibility of internal failure (see 6.16). Note: In order to determine the pressure of the shell during type testing and factory testing, the maximum value of the design pressure is expressed by the following formula: Maximum design pressure MPa (gauge pressure) = [rated inflation pressure (gauge pressure) + 0.1) × 1.30.1. 6.1.3 Sealing of the inflatable compartment
The manufacturer should explain what kind of pressure system the inflatable compartment uses and the allowable air leakage rate of the inflatable compartment. According to user requirements, it is necessary to enter the inflatable compartment of a closed pressure system or a controllable pressure system. The allowable leakage amount of gas passing through the partition should also be specified by the manufacturer.
For inflatable compartments where the minimum working pressure exceeds 0.1MPa (gauge pressure), when the ambient air is 20C and the pressure drops below the minimum working pressure, instructions must be given.
The partition between the gas-filled compartment and the liquid-filled compartment (e.g. cable box, voltage transformer) should not have any leakage affecting the insulation properties of the two media between them.
6.1.4 Pressure relief of inflatable compartments
The pressure relief design should minimize the danger that the operator may suffer from the gases and vapors released due to pressure during normal operation.
The pressure relief can be designed so that the arc burns at certain designated points on the shell, and the burned holes allow the pressure generated to be released.
6.1.5 Covers and doors
GB3906--91
When covers and doors are part of the enclosure, they shall be made of metal and shall have a The same protection level as the shell. Covers and doors shall not be constructed of mesh braid, drawn metal mesh, and similar materials. According to the different situations where it is necessary to enter the high-pressure compartment, the covers or doors are divided into two categories: a. For covers that do not need to be opened during normal operation and maintenance (fixed covers), if no tools are used, such covers should be Cannot be opened, disassembled or moved;
b. For covers (removable covers, doors) that need to be opened during normal operation and maintenance, tools should not be required when opening or moving such covers. In order to ensure the safety of the operator, an interlock or locking device should be installed. In armored or compartmented metal-enclosed switchgear, the cover or door may be opened only when the accessible part of the main circuit within the compartment is de-energized. For box-type switchgear, measures should also be taken (inserting safety partitions or other means) to prevent operators from touching live parts. 6.1.6 Observation window
Observation window shall meet the protection level specified by the enclosure. Observation window shall be covered with transparent flame retardant material with mechanical strength similar to that of the enclosure, and shall have sufficient electrical clearance or electrostatic shielding measures to prevent the formation of dangerous electrostatic charge (such as adding a suitable grounding braided mesh inside the observation window). The location of the observation window shall facilitate observation of the equipment in operation inside.
The insulation of the accessible surface between the live part of the main circuit and the observation window shall be able to withstand the test voltage to ground in Table 2 of GB11022.
6.1.7 Ventilation window, exhaust port
The arrangement or protection of ventilation window and exhaust port shall enable them to have the same protection level as the enclosure. Ventilation window can be made of mesh braid or similar material, but it shall have sufficient mechanical strength. The arrangement of ventilation window and exhaust port shall also take into account that the oil gas and steam discharged under pressure will not endanger the operator. 6.1.8 Temperature rise of the casing
In order to ensure that the operator is not burned, the temperature rise of the accessible casing and cover (including the accessible part of the inflatable compartment) should be limited to a level that people can tolerate. For casings or covers that do not need to be touched during normal operation of the equipment, the temperature rise can be appropriately increased. For parts of the casing that cannot be touched, the temperature rise should be limited to the temperature rise of the insulating material inside the casing not exceeding the allowable value. 6.2 Partitions and valves
6.2.1 General
Partitions and valves should meet one of the protection levels specified in Table 6 of Article 6.12 of GB11022. Partitions and valves can be metal or non-metal. If made of insulating materials, the following requirements shall be met: a. The live parts of the main circuit and the accessible surfaces of the insulating partitions and valves shall be able to withstand the test voltage to ground specified in Table 2 of GB11022:
b. In addition to having a certain mechanical strength, the insulating material shall also be able to withstand the power frequency test voltage specified in item a of this article. The test method is shown in GB1408;
The live parts of the main circuit and the inner surfaces of the insulating partitions and valves shall be able to withstand at least 1.5 times the rated voltage; c.
d. If there is a leakage current that can reach the accessible surface of the insulating partition and valve through a continuous path on the insulating surface, or through a path that is only separated by a small air gap or oil gap, then under the specified test conditions (see Article 7.8), this leakage current should not be greater than 0.5mA. Note: Small air gaps or oil gaps should be short-circuited during the test. There are openings for the removable contacts on the enclosure and on the partitions of armored and compartmentalized metal-enclosed switchgear, and the openings should be covered with reliable valves to ensure personal safety. If there are multiple sets of contacts, if one set of non-energized static contacts needs to be repaired, the remaining sets of static contacts should be locked in the closed position or inserted into a safety partition.
Note: The conductor passing through the metal partition can be insulated by bushings or similar methods, and the opening can be provided by bushings or insulating valves. 6.2.2 Partitions
GB390691
The partitions of armored metal-enclosed switchgear are made of metal and grounded. For compartmentalized and box-type metal-enclosed switchgear, if it will not become part of the enclosure in the grounding position, test position, disconnected position, and removed position, the partitions can be non-metallic; if the partitions are to become part of the enclosure in any of the above positions, they should be made of metal and grounded, and have the same degree of protection as the enclosure. Note: ① If it can be easily touched in any of the above positions, the partition becomes part of the enclosure. ② If a door that can be closed is provided in any of the above positions, the partition behind the door cannot be considered as part of the enclosure. Partitions between two gas-filled compartments or between one gas-filled compartment and another compartment, if they do not become part of the enclosure, can be made of insulating materials, but they cannot guarantee the electrical safety of the operator, which can be achieved by other means, such as grounding required by the equipment. Insulating partitions should ensure that the adjacent compartments have sufficient mechanical strength when the gas pressure is normal. 6.2.3 Valves
Valves of the three types of metal-enclosed switchgear can be made of metal or insulating materials. If the valve is made of insulating material, it cannot become part of the enclosure. If the valve is made of metal, it should be grounded. If the valve is to become part of the enclosure, it must be made of metal, completely cover the live parts and insulators and should be grounded, and should also have the same protection level as the enclosure. If a door that can be closed is provided in any of the grounding position, test position, disconnection position and removal position, the valve behind the door is not considered to be part of the enclosure.
6.2.4 Opening and closing of valves
6.2.4.1 If the withdrawable part of the metal-enclosed switchgear is in the test position or disconnection position, if the valve is open, there are two different situations:
a. The conductor of the main circuit of the withdrawable part is inaccessible (the withdrawable part and the fixed part have a protection level specified in Table 6 of Article 6.12 of GB11022). In this case, the design of the isolating break should be a series break composed of two fixed contacts and a movable contact of the same phase:
b. The main circuit conductor of the withdrawable part may be touched. In this case, the design of the isolating break should be between the fixed contact and the movable contact.
6.2.4.2 If the withdrawable parts of the metal-enclosed switchgear are in the test position or the disconnected position, if the valve is closed, then the protection level between the withdrawable parts and the fixed parts is not required. 6.3 Insulation board
In metal-enclosed switchgear, the insulation board added to improve the insulation level between phases and between phases and ground should have sufficient mechanical strength and electrical strength, and have good anti-aging performance and flame retardancy (which can be achieved by using certain coatings). Its setting should still ensure that there is a large air distance between phases and between phases and ground (for example: when the rated voltage is 10kV, the air net distance is not less than 60mm, and the phase-to-phase insulation board should be set in the middle position), otherwise, due to the influence of the electric field strength, the insulation board will be quickly destroyed (this article is not suitable for composite insulation structures with insulation directly installed or coated on live bodies).
6.4 Creepage distance of insulating parts
In order to ensure the insulation between phases and between phases and ground, the main circuit components are equipped with various insulating structural parts. In addition to meeting the corresponding insulation level, these insulating parts should also have a certain creepage distance. For 10kV metal-enclosed switchgear used under normal environmental conditions, the recommended creepage distance is:
Porcelain insulation---creepage distance not less than 12mm/kV Organic insulation--creepage distance not less than 14mm/kV Note: ① Creepage distance = maximum voltage × creepage distance. ② The creepage distance for 35kV metal-enclosed switchgear is under consideration. 6.5 Disconnectors (isolating plugs) and earthing switches Disconnectors and isolating plugs are devices that provide isolation breaks between high-voltage conductors. Disconnectors (isolating plugs) and earthing switches shall comply with the provisions of GB1985 in addition to the mechanical tests in accordance with Articles 7.6 and 8.2 of this standard. The operating position of the disconnector (isolating plug) and the earthing switch should be able to be determined. If one of the following conditions can be met, it is considered to be satisfied;
The isolating break is visible;
a.
b. The position of the removable part relative to the fixed part is clearly visible and has markings for the on and off positions;
6.6 Design of the main circuit
The conductors (including the main busbar and branch busbar) and the series components (excluding the short connection line from the fuse to the voltage transformer or transformer) of the main circuit of each functional unit should take into account the coordination of the parameters of the components of the circuit and the fact that the functional unit should be able to pass the specified rated current and dynamic and thermal stability current.
When considering the allowable temperature or temperature rise of the busbar, it should be determined based on the temperature or temperature rise of the contacts, connections and metal parts in contact with the insulating material.
6.7 Interlocking
In order to ensure reliable operation and operator safety, metal-enclosed switchgear should have the following functions: prevent disconnection and closing of disconnectors (isolating plugs) under load, prevent mis-opening and mis-closing of circuit breakers, load switches and contactors (allow prompting); prevent closing of circuit breakers, load switches and other switches when the grounding switch is in the closed position; prevent mis-closing of the grounding switch when energized; prevent mis-entry into energized compartments, etc. Separate provisions shall be made for metal-enclosed switchgear with removable parts and metal-enclosed switchgear without removable parts. 6.7.1 A metal-enclosed switchgear circuit breaker, load switch or contactor with removable parts that can be withdrawn or inserted only when it is in the open position. Only when the removable parts are in the working position, test position, disconnected position, grounding position, and removed position, the circuit breaker, load switch, and contactor can be opened and closed. Removable parts may only be brought into service position when the earthing switch (if any) is in the open position. The earthing switch is only allowed to be closed when the movable component is withdrawn to the test position and beyond. The removable parts should be extracted or inserted according to the normal operating force exerted by a normal person. The normal operating force is specified by the product technical conditions.
In the working position, if the auxiliary circuit is not connected, the circuit breaker, load switch and contactor cannot be closed, except for the case where the switch can open automatically without the auxiliary circuit.
6.7.2 Metal-enclosed switchgear without removable parts Only when the circuit breaker, load switch, and contactor are in the open position, the isolating switch can be opened and closed. However, if in a double-busbar system, the conversion without interruption of current is to be achieved, the above regulations may not be considered. If the isolating switch itself has a grounding switch, interlocking must be provided to ensure the programmability of their actions. At the same time, whether they can meet the insulation level requirements during movement must also be considered. The circuit breaker, load switch and contactor can only be operated when the isolating switches on both sides of the circuit breaker, load switch and contactor are in the closing, opening or grounding state (if any). 6.7.3 Other requirements for interlocking
a, the door and cover of the compartment can only be opened when the components of the compartment are not electrified and grounded (if any). If interlocking is installed It is inconvenient to allow the use of padlocks,
b. If the short-circuit closing capacity of the grounding switch is less than the rated dynamic stable current of the circuit, it is recommended to install an interlock with the relevant isolating switch.
C. Locking devices should be installed for those main circuit components that may cause damage due to misuse or are used to establish isolation fractures to ensure the safety of maintenance work.
material.
GB3906—91
d． If the user needs other additional interlocks, they can negotiate with the manufacturer for installation. The manufacturer should provide the interlock characteristics and necessary information. When designing, mechanical interlocks should be given priority. 6.8 Grounding
In addition to the grounding of each component on the metal-enclosed switchgear should comply with the provisions of 6.3 and 6.4 in GB11022, this standard makes the following supplements:
Set along the direction of the arrangement of the metal-enclosed switchgear. A grounding conductor. The grounding conductor should be able to meet the dynamic and thermal stable current requirements of the circuit. If it is made of copper, its current density should not exceed 200A/mm2 when a specified grounding fault occurs. Its cross-section should not be less than 30mm. The grounding conductor should not be less than 30mm. Conductors shall be provided with terminals for connection to the earthing system. NOTE: If the grounding conductor is not copper, the same thermal and dynamic stability requirements shall be met. When the passing current causes thermal and mechanical stress, the continuity of the grounding system should be ensured. It should be considered that the maximum value of the ground fault current is related to the form of the neutral point grounding of the operating system, and the user should explain it. When the grounding conductor carries a three-phase short-circuit current (such as a short-circuit connection for a grounding switch), refer to Appendix F to calculate the cross-section of the grounding conductor.
In order to ensure the safety of maintenance work, all accessible main circuit components should be able to be grounded, but this does not include accessible removable parts and extractable parts because they have been disconnected from the main circuit (excluding installation Removable parts with capacitor). Every enclosure shall be connected to a grounding conductor, and all metal parts, except for main and auxiliary circuits, that are designated to be grounded shall also be connected to the grounding conductor, either directly or through metal members. In order to ensure the electrical connection between the frame, door, cover, partition or other structure within the functional unit, screws or welding methods can be used. The door of the compartment should use a soft conductor (section not less than 4mm*) to connect to the frame through the grounding terminal. Connected. Withdrawable parts Metal parts that should be grounded should maintain the ground connection in the test position, the disconnected position and any intermediate position when the auxiliary circuit is not completely disconnected.
Circuit breaker, load switch, contactor If the component is completely disconnected from the main circuit due to the disconnection of the isolating switch and there is a grounded partition so that the compartment has the same protection level as the shell, the partition Maintenance of indoor components eliminates the need for grounding connections. Note: If there is a main circuit in this compartment connected to the components in this compartment, the main circuit must be grounded. 6.9 Auxiliary equipment
According to the provisions of Article 6.6 of GB11022, with the following supplement: Auxiliary equipment (including various instruments and relays) should be able to withstand the vibration caused by the opening and closing of the switch without malfunction. 6.10 The requirements for liquid media in metal-enclosed switchgear shall be in accordance with Article 6.1 of GB11022.
6.11 The requirements for gas media in metal-enclosed switchgear are in accordance with Article 6.2 of GB11022.
6.12 Opening operation
According to the provisions of Article 6.7 in GB11022.
6.13 Closing operation
According to the provisions of 6.8 in GB11022.
The operation of 6.14 tripper
According to the provisions of Article 6.9 in GB11022.
6.15 Protection level
According to the provisions of 6.12 in GB11022, with the following supplement: For armored and spaced metal-enclosed switchgear, the protection level can be specified separately for the shell and partition. For box-type metal-enclosed switchgear, only the protection level of the enclosure needs to be specified. For the main circuit of the inflatable compartment, the degree of protection need not be specified.In addition to the provisions of Article 4, this standard makes the following supplements:
A grounding conductor is set up along the direction in which the metal-enclosed switchgear is arranged. The grounding conductor should be able to meet the dynamic and thermal stable current requirements of the circuit. If it is made of copper , its current density should not exceed 200A/mm2 when a specified ground fault occurs, and its cross-section should not be less than 30mm. The grounding conductor should be equipped with terminals for connecting to the grounding system. NOTE: If the grounding conductor is not copper, the same thermal and dynamic stability requirements shall be met. When the passing current causes thermal and mechanical stress, the continuity of the grounding system should be ensured. It should be considered that the maximum value of the ground fault current is related to the form of the neutral point grounding of the operating system, and the user should explain it. When the grounding conductor carries a three-phase short-circuit current (such as a short-circuit connection for a grounding switch), refer to Appendix F to calculate the cross-section of the grounding conductor.
In order to ensure the safety of maintenance work, all accessible main circuit components should be able to be grounded, but this does not include accessible removable parts and extractable parts because they have been disconnected from the main circuit (excluding installation Removable parts with capacitor). Every enclosure shall be connected to a grounding conductor, and all metal parts, except for main and auxiliary circuits, that are designated to be grounded shall also be connected to the grounding conductor, either directly or through metal members. In order to ensure the electrical connection between the frame, door, cover, partition or other structure within the functional unit, screws or welding methods can be used. The door of the compartment should use a soft conductor (section not less than 4mm*) to connect to the frame through the grounding terminal. Connected. Withdrawable parts Metal parts that should be grounded should maintain the ground connection in the test position, the disconnected position and any intermediate position when the auxiliary circuit is not completely disconnected.
Circuit breaker, load switch, contactor If the component is completely disconnected from the main circuit due to the disconnection of the isolating switch and there is a grounded partition so that the compartment has the same protection level as the shell, the partition Maintenance of indoor components eliminates the need for grounding connections. Note: If there is a main circuit in this compartment connected to the components in this compartment, the main circuit must be grounded. 6.9 Auxiliary equipment
According to the provisions of Article 6.6 of GB11022, with the following supplement: Auxiliary equipment (including various instruments and relays) should be able to withstand the vibration caused by the opening and closing of the switch without malfunction. 6.10 The requirements for liquid media in metal-enclosed switchgear shall be in accordance with Article 6.1 of GB11022.
6.11 The requirements for gas media in metal-enclosed switchgear shall be in accordance with Article 6.2 of GB11022.
6.12 Opening operation
According to the provisions of Article 6.7 in GB11022.
6.13 Closing operation
According to the provisions of 6.8 in GB11022.
The operation of 6.14 tripper
is in accordance with the provisions of Article 6.9 in GB11022.
6.15 Protection level
According to the provisions of 6.12 in GB11022, with the following supplement: For armored and spaced metal-enclosed switchgear, the protection level can be specified separately for the shell and partition. For box-type metal-enclosed switchgear, only the protection level of the enclosure needs to be specified. For the main circuit of the inflatable compartment, the degree of protection need not be specified.In addition to the provisions of Article 4, this standard makes the following supplements:
A grounding conductor is set up along the direction in which the metal-enclosed switchgear is arranged. The grounding conductor should be able to meet the dynamic and thermal stable current requirements of the circuit. If it is made of copper , its current density should not exceed 200A/mm2 when a specified ground fault occurs, and its cross-section should not be less than 30mm. The grounding conductor should be equipped with terminals for connecting to the grounding system. NOTE: If the grounding conductor is not copper, the same thermal and dynamic stability requirements shall be met. When the passing current causes thermal and mechanical stress, the continuity of the grounding system should be ensured. It should be considered that the maximum value of the ground fault current is related to the form of the neutral point grounding of the operating system, and the user should explain it. When the grounding conductor carries a three-phase short-circuit current (such as a short-circuit connection for a grounding switch), refer to Appendix F to calculate the cross-section of the grounding conductor.
In order to ensure the safety of maintenance work, all accessible main circuit components should be able to be grounded, but this does not include accessible removable parts and extractable parts because they have been disconnected from the main circuit (excluding installation Removable parts with capacitor). Every enclosure shall be connected to a grounding conductor, and all metal parts, except for main and auxiliary circuits, that are designated to be grounded shall also be connected to the grounding conductor, either directly or through metal members. In order to ensure the electrical connection between the frame, door, cover, partition or other structure within the functional unit, screws or welding methods can be used. The door of the compartment should use a soft conductor (section not less than 4mm*) to connect to the frame through the grounding terminal. Connected. Withdrawable parts Metal parts that should be grounded should maintain the ground connection in the test position, the disconnected position and any intermediate position when the auxiliary circuit is not completely disconnected.
Circuit breaker, load switch, contactor If the component is completely disconnected from the main circuit due to the disconnection of the isolating switch and there is a grounded partition so that the compartment has the same protection level as the shell, the partition Maintenance of indoor components eliminates the need for grounding connections. Note: If there is a main circuit in this compartment connected to the components in this compartment, the main circuit must be grounded. 6.9 Auxiliary equipment
According to the provisions of Article 6.6 of GB11022, with the following supplement: Auxiliary equipment (including various instruments and relays) should be able to withstand the vibration caused by the opening and closing of the switch without malfunction. 6.10 The requirements for liquid media in metal-enclosed switchgear shall be in accordance with Article 6.1 of GB11022.
6.11 The requirements for gas media in metal-enclosed switchgear shall be in accordance with Article 6.2 of GB11022.
6.12 Opening operation
According to the provisions of Article 6.7 in GB11022.
6.13 Closing operation
According to the provisions of 6.8 in GB11022.
The operation of 6.14 tripper
is in accordance with the provisions of Article 6.9 in GB11022.
6.15 Protection level
According to the provisions of 6.12 in GB11022, with the following supplement: For armored and spaced metal-enclosed switchgear, the protection level can be specified separately for the shell and partition. For box-type metal-enclosed switchgear, only the protection level of the enclosure needs to be specified. For the main circuit of the inflatable compartment, the degree of protection need not be specified.
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