High-voltage switchgear and phase spacing determination method

Abstract

The invention relates to the technical field of power distribution, in particular to high-voltage switch equipment and a phase spacing determination method. The high-voltage switch equipment comprises a switch cabinet, a lower branch bus, an overhead incoming and outgoing line and a grounding switch, the lower branch bus comprises A, B and C phase branch buses, a grounding switch shaft mechanically connected with the grounding switch is arranged at the C phase branch bus of the lower branch bus in the switch cabinet, and a bus sleeve is arranged at the grounding switch shaft on each phase branch bus of the lower branch bus. A phase distance satisfying a standard air purification distance is formed between adjacent single-phase branch buses in the lower branch buses and between the single-phase branch buses and the switch cabinet shell on the corresponding side, and an insulation distance satisfying the standard air purification distance is formed between a C-phase branch bus in the lower branch buses and the grounding switch shaft. According to the invention, under the condition that the width of the switch cabinet is not changed, the standard air net distance between the adjacent single-phase branch buses in the switch cabinet and between the C-phase branch bus in the lower branch bus and the grounding switch shaft can be satisfied.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution, and particularly to a high-voltage switchgear and a method for determining phase spacing. Background Art

[0002] High-voltage switchgear is an indoor complete set of power distribution equipment, which is used in power plants, substations and industrial and mining enterprises to receive and distribute electric energy, and plays functions such as controlling, protecting and monitoring the circuit. As power distribution equipment, it is required that the air clearance of the equipment meets the corresponding standards.

[0003] The current overhead scheme is that the busbar exits from the top of the high-voltage switchgear, and the outgoing cabinet often has an earthing switch. Due to the operation of the earthing switch, it is easy to cause the insulation distance between the overhead busbar and the earthing switch shaft to be less than 300 mm, which cannot meet the requirements of the standard air clearance. To solve this problem, most existing manufacturers usually lower the earthing switch shaft to about 300 mm above the ground. However, this method is inconvenient to operate because the distance between the operating shaft and the ground is small. Summary of the Invention

[0004] The technical problem to be solved by the embodiments of the present invention is to provide a high-voltage switchgear and a method for determining phase spacing to solve the problem that the overhead scheme of the high-voltage switchgear in the prior art does not meet the requirements of the standard air clearance.

[0005] The present invention discloses a high-voltage switchgear, including a switch cabinet, a lower branch busbar, an overhead incoming and outgoing line, and an earthing switch. A cable chamber is separated in the switch cabinet. The lower branch busbar and the overhead incoming and outgoing line are electrically connected in the cable chamber, and the overhead incoming and outgoing line exits at the top of the cable chamber. The earthing switch is arranged in the cable chamber on the cabinet door of the switch cabinet, and the earthing switch is electrically connected to the lower branch busbar; The lower branch busbar includes phase A, B, and C branch busbars. At the position of the phase C branch busbar of the lower branch busbar in the switch cabinet, an earthing switch shaft mechanically connected to the earthing switch is arranged, and a bushing is arranged on each phase branch busbar of the lower branch busbar at the position of the earthing switch shaft; Between adjacent single-phase branch busbars in the lower branch busbar, and between the single-phase branch busbar and the corresponding side of the switch cabinet housing, a phase spacing that meets the standard air clearance is formed through the corresponding bushing, and an insulation spacing that meets the standard air clearance is formed between the phase C branch busbar in the lower branch busbar and the earthing switch shaft through the corresponding bushing.

[0006] Optionally, a lower contact box and a current transformer are arranged in the cable chamber. One end of the lower branch busbar is fixed through the lower contact box, and the lower contact box, the current transformer, and the earthing switch are sequentially connected through the lower branch busbar.

[0007] Optionally, the phase spacings of the lower contact box, the lower branch busbar, the current transformer, and the earthing switch are the same.

[0008] Optionally, a busbar chamber is partitioned above the cable chamber in the switchgear cabinet. An upper branch busbar and an upper contact box are arranged in the busbar chamber. One end of the upper branch busbar is fixed through the upper contact box. A wall bushing is also arranged in the busbar chamber, and the upper branch busbar is electrically connected to the main busbar through the wall bushing.

[0009] Optionally, a mounting plate spanning the cable chamber and the busbar chamber is arranged in the switchgear cabinet. The upper contact box and the lower contact box are both arranged on the mounting plate.

[0010] Optionally, first insulators corresponding to and connected to each phase branch busbar of the upper branch busbar are arranged in the busbar chamber to electrically isolate each phase branch busbar in the upper branch busbar.

[0011] Optionally, both the upper branch busbar and the lower branch busbar are rounded-corner branch busbars, and overhead inlet and outlet bushings are arranged on the overhead inlet and outlet lines.

[0012] Optionally, both the upper branch busbar and the lower branch busbar include phase A, B, and C branch busbars, and the phase spacings of the upper branch busbar, the upper contact box, and the lower branch busbar are the same.

[0013] Optionally, a circuit breaker chamber is partitioned on the side of the cable chamber in the switchgear cabinet. A circuit breaker trolley is arranged in the circuit breaker chamber. The circuit breaker trolley includes a vehicle body, and an upper contact and a lower contact arranged on the vehicle body. The upper contact is used to connect to the upper branch busbar through the upper contact box, and the lower contact is used to connect to the lower branch busbar through the lower contact box.

[0014] The present invention also discloses a method for determining phase spacing, which is applied to the above-mentioned high-voltage switchgear. The method for determining phase spacing includes: Measuring and obtaining the width of a single-phase branch busbar in the lower branch busbar; Presetting the phase spacing between adjacent single-phase branch busbars in the lower branch busbar. According to the obtained width of the single-phase branch busbar and the phase spacing between adjacent single-phase branch busbars, calculating the air clearance between adjacent single-phase branch busbars. The calculation formula for the air clearance between adjacent single-phase branch busbars is:

[0015] In the formula, represents the air clearance between adjacent single-phase branch busbars, represents the preset phase spacing between adjacent single-phase branch busbars, represents the width of the single-phase branch busbar; Measure and obtain the width of the switchgear and the thickness of the switchgear housing. According to the obtained width of the switchgear, the thickness of the switchgear housing, and the width of the single-phase branch busbar, calculate the air clearance between the single-phase branch busbars on both sides of the lower branch busbar and the switchgear housing. The calculation formula for the air clearance between the single-phase branch busbar and the switchgear housing is:

[0016] In the formula, represents the air clearance between the single-phase branch busbars on both sides of the lower branch busbar and the switchgear housing, represents the width of the switchgear, represents the thickness of the switchgear; If the air clearance between adjacent single-phase branch busbars in the lower branch busbar and the air clearance between the single-phase branch busbars on both sides and the switchgear housing both meet the standard air clearance, then determine that the preset phase spacing between adjacent single-phase branch busbars in the lower branch busbar is the layout parameter of the phase spacing of the lower branch busbar in the switchgear.

[0017] Compared with the prior art, the beneficial effects of the high-voltage switchgear and the phase-spacing determination method provided by the embodiments of the present invention are as follows: A switchgear, a lower branch busbar, overhead incoming and outgoing lines, and an earthing switch are provided. By arranging bushing tubes at the shaft of the earthing switch on each phase branch busbar of the lower branch busbar, the phase spacing that meets the standard air clearance is formed between adjacent single-phase branch busbars in the lower branch busbar and between the single-phase branch busbars on both sides and the corresponding side of the switchgear housing through the corresponding bushing tubes, so as to use three bushing tubes to replace the insulating board between adjacent single-phase branch busbars in the traditional high-voltage switchgear. Thus, on the premise that the width of the switchgear remains unchanged, the air clearance between adjacent single-phase branch busbars in the switchgear is not less than 300 mm, and an insulating spacing that meets the standard air clearance is formed between the C-phase branch busbar in the lower branch busbar and the shaft of the earthing switch through the corresponding bushing tube to meet the requirements of the latest 18 anti-measurements of the State Grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The technical solutions of the present invention will be further described in detail below in conjunction with the drawings. In the drawings: Figure 1 is the overall structural schematic diagram of the high-voltage switchgear provided by the embodiment of the present invention; Figure 2 is the structural schematic diagram corresponding to the phase spacing of the upper branch busbar and the lower branch busbar provided by the embodiment of the present invention; Figure 3 is the structural schematic diagram of the connection line of the lower branch busbar inside the cable chamber provided by the embodiment of the present invention.

[0019] The reference numerals in the figures are as follows: 1. Switchgear cabinet; 11. Cable chamber; 12. Lower contact box; 13. Current transformer; 14. Busbar chamber; 15. Upper branch busbar; 16. Upper contact box; 17. Circuit breaker chamber; 18. Circuit breaker trolley; 181. Upper contact; 182. Lower contact; 2. Lower branch busbar; 21. Busbar bushing; 3. Overhead incoming and outgoing line; 4. Earthing switch; 5. Earthing switch shaft; 6. Mounting plate; 7. First insulator; 8. Overhead incoming and outgoing bushing. Detailed implementation manners

[0020] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. Now, with reference to the accompanying drawings, the preferred embodiments of the present invention will be described in detail.

[0021] The present invention discloses a high-voltage switchgear device, as Figures 1 - 3 shown, which includes a switchgear cabinet 1, a lower branch busbar 2, an overhead incoming and outgoing line 3, and an earthing switch 4. A cable chamber 11 is partitioned in the switchgear cabinet 1. The lower branch busbar 2 and the overhead incoming and outgoing line 3 are electrically connected in the cable chamber 11, and the overhead incoming and outgoing line 3 extends out at the top of the cable chamber 11. The earthing switch 4 is arranged in the cable chamber 11 on the cabinet door of the switchgear cabinet 1, and the earthing switch 4 is electrically connected to the lower branch busbar 2; The lower branch busbar 2 includes phase A, B, and C branch busbars. At the position of the phase C branch busbar of the lower branch busbar 2 in the switchgear cabinet 1, an earthing switch shaft 5 mechanically connected to the earthing switch 4 is provided, and a busbar bushing 21 is provided at the position of each phase branch busbar of the lower branch busbar 2 at the earthing switch shaft 5; Between adjacent single-phase branch busbars in the lower branch busbar 2, and between the single-phase branch busbar and the corresponding side of the switchgear cabinet 1 housing, a phase spacing that meets the standard air clearance is formed through the corresponding busbar bushing 21, and an insulation spacing that meets the standard air clearance is formed between the phase C branch busbar and the earthing switch shaft 5 in the lower branch busbar 2 through the corresponding busbar bushing 21.

[0022] Through the implementation of the above embodiments of the high-voltage switchgear, a switch cabinet 1, a lower branch bus 2, overhead incoming and outgoing lines 3, and an earthing switch 4 are provided. The cable chamber 11 formed by partitioning inside the switch cabinet 1 can protect cables and electrical components from the external environment, and at the same time facilitate maintenance and repair. The overhead incoming and outgoing lines 3 are located at the top of the cable chamber 11, which is convenient for connecting to the overhead line upwards, reducing the occupation of horizontal space. At the same time, the routing is optimized using the top space, so that the external overhead line can be directly connected to the switch cabinet 1 without complex external connections. The lower branch bus 2 (three phases A, B, and C) and the overhead incoming and outgoing lines 3 are electrically connected inside the cable chamber 11 to form a main power supply circuit for power transmission. The earthing switch 4 is installed inside the cabinet door of the switch cabinet 1, and its operating handle is located outside the cabinet door, which is convenient for quick operation during maintenance.

[0023] The shaft of the earthing switch 4 is installed near the C-phase branch bus, and is linked with the earthing switch 4 on the cabinet door through a mechanical transmission mechanism. By providing a bushing 21 at the shaft of the earthing switch 4 on each phase branch bus of the lower branch bus 2, it not only ensures the insulation isolation between the C-phase branch bus and the shaft of the earthing switch 4 in the lower branch bus 2, but also provides mechanical support for each phase branch bus. When the earthing switch 4 is operated, the earthing contact of the lower branch bus 2 is driven to close, forming an earthing circuit with the lower branch bus 2. Since the lower branch bus 2 is a three-phase branch bus and is interconnected through a neutral point or common earthing design in the whole line, when the earthing contact is closed, the three-phase busbars are grounded synchronously through a low-impedance path.

[0024] During normal operation: the lower branch bus 2 is energized, the earthing switch 4 is in the open state, and each bushing 21 maintains the insulation of each phase branch bus.

[0025] When closing the earthing switch 4: operate the earthing switch 4 on the cabinet door, and through the linkage of the earthing switch 4 shaft, the lower branch bus 2 is grounded, and all three phases are grounded due to the system connection.

[0026] As described above, each phase branch bus is wrapped by the bushing 21 with an insulating material to ensure that the phase spacing that meets the standard air clearance is formed between adjacent single-phase branch buses in the lower branch bus 2, and between the single-phase branch buses on both sides and the corresponding side of the switch cabinet 1 housing through the corresponding bushing 21. The phase spacing is preferably 360 mm. And the insulating board between adjacent single-phase branch buses in the traditional high-voltage switch cabinet 1 is cancelled, so as to ensure that the air clearance between adjacent single-phase branch buses in the switch cabinet 1 is not less than 300 mm without changing the width of the switch cabinet 1, and an insulating spacing that meets the standard air clearance is formed between the C-phase branch bus in the lower branch bus 2 and the shaft of the earthing switch 4 through the corresponding bushing 21 to meet the requirements of the latest 18 anti-measures of the State Grid.

[0027] Further, a lower contact box 12 and a current transformer 13 are arranged in the cable chamber 11. One end of the lower branch bus 2 is fixed through the lower contact box 12, and the lower contact box 12, the current transformer 13, and the earthing switch 4 are sequentially connected through the lower branch bus 2.

[0028] Further, the phase spacings of the lower contact box 12, the lower branch bus 2, the current transformer 13, and the earthing switch 4 are all the same.

[0029] Through the implementation of the above embodiments of the high-voltage switchgear, by using the lower contact box 12 to fix one end of the lower branch bus 2, the stability of the lower branch bus 2 and the reliability of the electrical connection can be ensured. Connecting the lower contact box 12, the current transformer 13, and the earthing switch 4 sequentially through the lower branch bus 2 enables the current transformer 13 to be used for providing real-time current monitoring to help detect problems in a timely manner and take measures. The earthing switch 4 ensures that in case of a fault, the current can flow quickly and safely to the ground, reducing the risk of electric shock. Thus, through centralized control in the cable chamber 11, the power system can be monitored and managed more effectively. In addition, since the lower branch bus 2 is a three-phase bus, the matching lower contact box 12, lower branch bus 2, current transformer 13, and earthing switch 4 are set with the same phase spacing, which is preferably 360 mm, to ensure that the air clearance between phases in the switch cabinet 1 is not less than 300 mm, so that the switch cabinet 1 in the embodiment of the present invention meets the requirement in the national grid anti-measure that the relative air clearance is not less than 300 mm.

[0030] Further, a bus chamber 14 is partitioned above the cable chamber 11 in the switch cabinet 1. An upper branch bus 15 and an upper contact box 16 are arranged in the bus chamber 14. One end of the upper branch bus 15 is fixed through the upper contact box, a wall bushing is also arranged in the bus chamber 14, and the upper branch bus 15 is electrically connected to the main bus through the wall bushing.

[0031] Through the implementation of the above embodiments of the high-voltage switchgear, partitioning the bus chamber 14 above the cable chamber 11 realizes electrical isolation between the cable chamber 11 and the bus chamber 14 to prevent external electrical interference. Fixing one end of the upper branch bus 15 through the upper contact box 16 ensures a reliable connection between the upper branch bus 15 inside the bus chamber 14 and other electrical devices or systems. Setting the wall bushing allows the upper branch bus 15 to be electrically connected to the main bus on the other side of the wall, and the use of the wall bushing can provide additional protection against external physical damage and electrical interference. By centrally placing the upper branch bus 15 and the upper contact box 16 in the bus chamber 14, space can be saved and the internal layout of the switch cabinet 1 can be optimized.

[0032] Further, an installation plate 6 spanning the cable chamber 11 and the bus chamber 14 is arranged in the switch cabinet 1. Both the upper contact box 16 and the lower contact box 12 are arranged on the installation plate 6.

[0033] Through the implementation of the above embodiments of the high-voltage switchgear, by providing a mounting plate 6 in the switch cabinet 1, a common platform is utilized, enabling the upper contact box 16 and the lower contact box 12 to be conveniently installed and connected, making more effective use of space, and making the layout of electrical components more reasonable and compact, so as to achieve the continuity and integrity of the electrical system.

[0034] Further, a first insulator 7 is provided in the busbar chamber 14 and is connected to each phase busbar of the upper branch busbar 15 one by one, so as to electrically isolate each phase busbar in the upper branch busbar 15.

[0035] Through the implementation of the above embodiments of the high-voltage switchgear, by providing a first insulator 7 for each phase busbar of the upper branch busbar 15 in the busbar chamber 14, it can ensure that electrical isolation can be achieved between each phase busbar, prevent current from interfering with each other between different phases, maintain phase isolation to help maintain the stable operation of the power system, and avoid system shutdown caused by electrical faults. And it reduces the risk of electric shock caused by phase contact or incorrect connection, making the maintenance work safer.

[0036] Further, both the upper branch busbar 15 and the lower branch busbar 2 are rounded-corner busbars, and an overhead inlet / outlet sleeve 8 is provided on the overhead inlet / outlet line 3.

[0037] Through the implementation of the above embodiments of the high-voltage switchgear, since the single-layer busbar with a busbar specification of TMY60X12 is mostly used in traditional high-voltage switches, the air clearance between phases cannot meet 300 mm after the busbar sleeve is heat-shrunk. Therefore, in the embodiments of the present invention, a rounded-corner busbar with a busbar specification of 2XTMY50X10 is preferably selected to ensure that the air clearance between phases reaches or exceeds 300 mm by increasing the number of layers of the busbar and optimizing the design, thereby helping to combine the layout of the phase spacing and optimizing the layout form of the lower branch busbar 2 to meet safety specifications and reduce the short-circuit risk. In addition, the overhead inlet / outlet sleeve 8 provides an insulating isolation layer between the overhead inlet / outlet line 3 and the internal electrical equipment of the switch cabinet 1, preventing current leakage and electrical short circuits, and ensuring the safety of operators.

[0038] Further, both the upper branch busbar 15 and the lower branch busbar 2 include phase A, B, and C busbars, and the phase spacings of the upper branch busbar 15, the upper contact box, and the lower branch busbar 2 are the same.

[0039] By implementing the above embodiments of the high-voltage switchgear, since the upper branch bus 15 is also a three-phase bus, the same phase spacing is set for the matching upper branch bus 15, upper contact box, and lower branch bus 2. This phase spacing is preferably 360 mm to further ensure that the air clearance between phases in the switchgear 1 is not less than 300 mm, enabling the switchgear 1 of the embodiments of the present invention to meet the requirement in the State Grid anti-measure that the relative air clearance is not less than 300 mm.

[0040] Furthermore, a circuit breaker compartment 17 is separated on the side of the cable compartment 11 in the switchgear 1. A circuit breaker trolley 18 is arranged in the circuit breaker compartment 17. The circuit breaker trolley 18 includes a vehicle body, and an upper contact 181 and a lower contact 182 arranged on the vehicle body. The upper contact 181 is used to connect to the upper branch bus 15 through the upper contact box 16, and the lower contact 182 is used to connect to the lower branch bus 2 through the lower contact box 12.

[0041] By implementing the above embodiments of the high-voltage switchgear, an independent circuit breaker compartment 17 is separated on the side of the cable compartment 11 to achieve physical isolation of electrical components, improve operation safety, and prevent misoperation. The upper contact 181 of the circuit breaker trolley 18 is connected to the upper branch bus 15 through the upper contact box 16, and the lower contact 182 is used to connect to the lower branch bus 2 through the lower contact box 12. When the two contacts of the circuit breaker trolley 18 are in the working position, the upper branch bus 15 and the lower branch bus 2 are conducted to allow current to smoothly pass from the bus compartment 14 through the circuit breaker trolley 18 to the cable compartment 11, thereby achieving the closing of the circuit.

[0042] The present invention also discloses a method for determining the phase spacing, which is applied to the above high-voltage switchgear. The method for determining the phase spacing includes: Measuring and obtaining the width of a single-phase branch bus in the lower branch bus 2; Presetting the phase spacing between adjacent single-phase branch buses in the lower branch bus 2. According to the obtained width of the single-phase branch bus and the phase spacing between adjacent single-phase branch buses, the air clearance between adjacent single-phase branch buses is calculated. The calculation formula for the air clearance between adjacent single-phase branch buses is:

[0043] In the formula, represents the air clearance between adjacent single-phase branch buses, represents the preset phase spacing between adjacent single-phase branch buses, represents the width of the single-phase branch bus; Measure the width of switchgear cabinet 1 and the thickness of the housing of switchgear cabinet 1. According to the obtained width of switchgear cabinet 1, the thickness of the housing of switchgear cabinet 1, and the width of the single-phase branch bus, calculate the air clearance between the single-phase branch buses on both sides in the lower branch bus 2 and the housing of switchgear cabinet 1. The calculation formula for the air clearance between the single-phase branch bus and the housing of switchgear cabinet 1 is:

[0044] In the formula, represents the air clearance between the single-phase branch buses on both sides in the lower branch bus 2 and the housing of switchgear cabinet 1, represents the width of switchgear cabinet 1, represents the thickness of switchgear cabinet 1; If the air clearance between adjacent single-phase branch buses in the lower branch bus 2 and the air clearance between the single-phase branch buses on both sides and the housing of switchgear cabinet 1 both meet the standard air clearance, then determine that the preset phase spacing between adjacent single-phase branch buses in the lower branch bus 2 is the layout parameter of the phase spacing of the lower branch bus 2 in switchgear cabinet 1.

[0045] Through the implementation of the embodiment of the above phase spacing determination method, calculate the air clearance between adjacent single-phase branch buses in the lower branch bus 2 and the air clearance between the single-phase branch buses on both sides and the housing of switchgear cabinet 1 respectively. When both air clearances meet the standard air clearance, determine that the preset phase spacing between adjacent single-phase branch buses in the lower branch bus 2 is the layout parameter of the phase spacing of the lower branch bus 2 in switchgear cabinet 1 to ensure that the air clearance between adjacent single-phase branch buses in switchgear cabinet 1 is not less than 300 mm. If any one of the two calculated air clearances does not meet the standard air clearance, it is necessary to re-preset the phase spacing between adjacent single-phase branch buses in the lower branch bus 2.

[0046] Furthermore, as shown in combination with Figure 2 and Figure 3 for example, with fixed parameters: the width of switchgear cabinet 1 is 1400 mm, the thickness of the housing of switchgear cabinet 1 is 4 mm, and the width of the single-phase branch bus is 50 mm: First, preset the phase spacing between adjacent single-phase branch buses in the lower branch bus 2 to be 360 mm; Calculate the air clearance between adjacent single-phase branch buses in the lower branch bus 2, that is:

[0047] Then calculate the air clearance between the single-phase branch buses on both sides in the lower branch bus 2 and the housing of switchgear cabinet 1, that is:

[0048] As can be seen from the above calculations, the net air distance of 310 mm between adjacent single-phase branch busbars in the lower branch busbar 2 and the net air distance of 311 mm between the single-phase branch busbars on both sides and the cabinet body of the switchgear 1 are not less than 300 mm. Therefore, the preset phase spacing of 360 mm is applicable to the high-voltage switchgear with a width of 1400 mm for the switchgear 1, a cabinet body thickness of 4 mm for the switchgear 1, and a width of 50 mm for the single-phase branch busbar.

[0049] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Those skilled in the art can modify the technical solutions described in the above embodiments or equivalently replace some of the technical features therein; and all such modifications and replacements should fall within the protection scope of the present invention.

Claims

1. A high voltage switchgear, characterized in that: The high-voltage switchgear comprises a switch cabinet, a lower branch busbar, an overhead incoming and outgoing line and a grounding switch. A cable room is formed in the switch cabinet. The lower branch busbar and the overhead incoming and outgoing line are electrically connected in the cable room, and the overhead incoming and outgoing line is located at the top of the cable room. The grounding switch is located in the cable room and is arranged on the cabinet door of the switch cabinet, and the grounding switch is electrically connected to the lower branch busbar. The lower branch busbar includes A, B, and C phase branch busbars. A grounding switch shaft mechanically connected to the grounding switch is provided at the C phase branch busbar of the lower branch busbar in the switch cabinet. A busbar bushing is provided at the grounding switch shaft on each phase branch busbar of the lower branch busbar. Between adjacent single-phase branch busbars in the lower branch busbar, and between the single-phase branch busbars on both sides and the switch cabinet housing on the corresponding side, a phase spacing that meets the standard air clearance distance is formed through the corresponding busbar bushings, and between the C-phase branch busbar in the lower branch busbar and the grounding switch shaft, an insulation spacing that meets the standard air clearance distance is formed through the corresponding busbar bushings.

2. The high voltage switchgear according to claim 1, characterized in that: A lower contact box and a current transformer are arranged in the cable room, one end of the lower branch bus is fixed by the lower contact box, and the lower contact box, the current transformer and the grounding switch are connected in sequence by the lower branch bus.

3. The high voltage switchgear according to claim 2, characterized in that: The phase spacings of the lower contact box, the lower branch bus, the current transformer and the grounding switch are all the same.

4. The high voltage switchgear according to claim 3, characterized in that: A busbar chamber is formed by separating the switch cabinet above the cable chamber, wherein an upper branch busbar and an upper contact box are arranged in the busbar chamber, one end of the upper branch busbar is fixed by the upper contact box, a wall bushing is also arranged in the busbar chamber, and the upper branch busbar is electrically connected to the main busbar through the wall bushing.

5. The high voltage switchgear according to claim 4, characterized in that: A mounting plate spanning the cable chamber and the busbar chamber is arranged in the switch cabinet, and the upper contact box and the lower contact box are both arranged on the mounting plate.

6. The high voltage switchgear according to claim 4, characterized in that: The busbar chamber is provided with a first insulator connected one-to-one with each phase branch busbar of the upper branch busbar, so as to electrically isolate each phase branch busbar in the upper branch busbar.

7. The high voltage switchgear according to claim 4, characterized in that: The upper branch busbar and the lower branch busbar are both rounded branch busbars, and overhead inlet and outlet bushings are arranged on the overhead inlet and outlet lines.

8. The high voltage switchgear according to claim 4, characterized in that: The upper branch busbar and the lower branch busbar both include A-phase, B-phase, and C-phase branch busbars, and the phase spacings of the upper branch busbar, the upper contact box, and the lower branch busbar are all the same.

9. The high voltage switchgear according to claim 8, characterized in that: A circuit breaker chamber is formed by partitioning the switch cabinet on the side of the cable chamber. A circuit breaker trolley is arranged in the circuit breaker chamber. The circuit breaker trolley includes a car body, and upper contacts and lower contacts arranged on the car body. The upper contact is used to connect to the upper branch busbar through the upper contact box, and the lower contact is used to connect to the lower branch busbar through the lower contact box.

10. A method for determining phase spacing, applied to the high-voltage switchgear according to any one of claims 1 to 9, characterized in that: The phase spacing determination method comprises: Measure and obtain the width of the single-phase branch bus in the lower branch bus; The phase spacing between adjacent single-phase branch busbars in the lower branch busbar is preset, and the air clearance between adjacent single-phase branch busbars is calculated according to the acquired width of the single-phase branch busbars and the phase spacing between adjacent single-phase branch busbars. The calculation formula for the air clearance between adjacent single-phase branch busbars is: In the formula, Indicates the air clearance between adjacent single-phase branch busbars. Indicates the preset phase spacing between adjacent single-phase branch buses. Indicates the width of the single-phase branch bus; The width of the switch cabinet and the shell thickness of the switch cabinet are measured and obtained. According to the obtained width of the switch cabinet, the shell thickness of the switch cabinet, and the width of the single-phase branch bus, the air clearance between the single-phase branch busbars on both sides of the lower branch busbar and the switch cabinet shell is calculated. The calculation formula for the air clearance between the single-phase branch busbar and the switch cabinet shell is: In the formula, Indicates the air clearance between the single-phase branch busbars on both sides of the lower branch busbar and the switch cabinet housing. Indicates the width of the switch cabinet, Indicates the thickness of the switchgear; If the air clearance between adjacent single-phase branch busbars in the lower branch busbar, and the air clearance between the single-phase branch busbars on both sides and the switch cabinet housing meet the standard air clearance distance, the preset phase spacing between adjacent single-phase branch busbars in the lower branch busbar is determined as the layout parameter of the phase spacing of the lower branch busbar in the switch cabinet.

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