Midpoint direct current switch (MBTS) for cutting off single-ended converter valve and converter station

Abstract

The invention relates to the technical field of emergency protection circuit devices, in particular to a midpoint direct current switch (MBTS) for cutting off a single-ended converter valve and a converter station. The MMTS for cutting off the single-ended converter valve comprises a pillar sleeve, an arc extinguish chamber arranged on the pillar sleeve, an insulating platform arranged close to the pillar sleeve and a capacitor arranged on the insulating platform, and the pillar sleeve and the insulating platform are respectively used for meeting the ground insulation requirements of the arc extinguish chamber and the capacitor. The arc extinguish chamber is connected with the capacitors to form a series resonance circuit, two ends of the capacitors are connected with nonlinear resistors to prevent overvoltage from damaging the capacitors and fractures and meet the energy release requirement of a direct current system after the direct current switch is switched off, and a plurality of capacitors are connected in series and in parallel to form a capacitor bank. According to the MMTS for cutting off the single-end converter valve, when the fault of the converter valve is detected, the faulted converter valve is cut off, other converter valves in normal operation are not influenced, and the transmission efficiency of a direct-current power transmission system is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of emergency protection circuit devices, and in particular to a midpoint direct current switch (MBTS) for cutting off a single-ended converter valve and a converter station. Background Art

[0002] DC transmission technology occupies an important position in the power system due to its high efficiency, low loss and long-distance transmission capacity. Compared with traditional AC transmission methods, DC transmission has shown significant advantages in reducing energy loss, improving power grid transmission capacity and flexibility. The core of the DC transmission system is the converter valve, which is used to convert DC power into AC power or AC power into DC power at the converter station. The converter valve connects the AC power grid and the DC transmission line like a bridge, and its performance is directly related to the overall efficiency and stability of the transmission system. However, the converter valve is prone to various faults such as short circuit, open circuit or control failure due to long-term exposure to high voltage, high current, lightning strikes, pollution, aging and other external factors, which will directly affect the DC power transmission of the transmission line. In extreme cases, in order to avoid the expansion of the fault or cause more serious damage, the system may need to stop part or even all of the DC power transmission, which will have a huge impact on the transmission efficiency of the DC system.

[0003] When the converter valve is in use, multiple converter valves are usually connected in series or in parallel to form a valve group. The valve group is divided into a high-voltage converter valve group and a low-voltage converter valve group according to the transmission voltage. The high-voltage converter valve group and the low-voltage converter valve group work together to complete the conversion from AC to DC. Figure 1 As shown, the converter valve group on the positive side of the DC bus and the converter valve group on the negative side of the DC bus are connected through the neutral bus switch (NBS), and the connection point is connected to the grounding system through the metal return line transfer switch (MRTS) to achieve single-pole or double-pole metal operation. A ground return line transfer switch (GRTS) for achieving single-pole operation and a neutral bus grounding switch (NBGS) are also provided. When the circuit is in normal operation, it is a double-pole operation. The two neutral bus switches (NBS) are normally closed, the metal return line transfer switch (MRTS) is normally closed, the ground return line transfer switch (GRTS) and the neutral bus grounding switch (NBGS) are normally open, and the DC transmission power is output from the converter valve group on the positive side of the DC bus and the converter valve group on the negative side of the DC bus to the opposite side through the transmission line.

[0004] When any converter valve in the valve group fails, there are two traditional solutions. One is to cut off the valve group where the faulty valve is located from the converter station circuit system, and the other valve groups work normally, forming a single-pole metal operation mode or a single-pole ground operation mode; the other is to cut off all the converter valve groups. Specifically, the neutral bus switch (NBS) in series with the valve group where the faulty valve is located is disconnected, the metal return line transfer switch (MRTS) is closed, and power is transmitted from the normal valve group to the outside. This state is a single-pole metal operation mode; the neutral bus switch (NBS) and the metal return line transfer switch (MRTS) in series with the valve group where the faulty valve is located are disconnected, and the ground return line transfer switch (GRTS) is closed, and power is transmitted from the normal valve group to the outside. This state is a single-pole ground operation mode. During single-pole metal operation, if the grounding system fails, the neutral bus grounding switch (NBGS) is used to achieve temporary grounding in the converter station to avoid overvoltage affecting the overall circuit.

[0005] Whether it is unipolar operation or all converter valves are cut off, it will have a great impact on the transmission of DC power, such as causing voltage fluctuations and other problems, and will also affect the power balance of the entire power grid and the stability and safety of the entire power system. Therefore, improving the transmission power of the DC transmission system under the condition of converter valve failure and reducing the power loss caused by a single converter valve failure has become a key issue in the power industry. Summary of the invention

[0006] The object of the present invention is to provide a midpoint DC switch (MBTS) and a converter station for cutting off a single-ended converter valve, so as to solve the problem of affecting the overall transmission power of a DC transmission system under a converter valve failure condition and reduce the power loss caused by a single converter valve failure.

[0007] In order to solve the above problems, the midpoint DC switch (MBTS) for cutting off the single-ended converter valve of the present invention adopts the following technical solutions: A midpoint DC switch (MBTS) for cutting off a single-ended converter valve comprises a support bushing, an arc extinguishing chamber arranged on the support bushing, an insulating platform arranged near the support bushing and a capacitor arranged on the insulating platform. The support bushing and the insulating platform are respectively used to meet the insulation requirements of the arc extinguishing chamber and the capacitor to the ground. The arc extinguishing chamber is connected with the capacitor to form a series resonant circuit. Nonlinear resistors are connected at both ends of the capacitor to avoid damage to the capacitor and the break caused by excessive voltage on the capacitor and meet the energy release requirements of the DC system after the DC switch is disconnected. There are multiple capacitors connected in series and parallel to form a capacitor bank.

[0008] Furthermore, a mounting bracket is provided at the lower end of the support sleeve for mounting an operating mechanism of the arc extinguishing chamber, and the operating mechanism is used to drive a pull rod provided in the support sleeve to enable the arc extinguishing chamber to perform opening and closing movements.

[0009] Furthermore, a support insulator is provided below the insulating platform, and the support insulator supports the insulating platform through longitudinal beams and transverse beams provided at the bottom of the insulating platform, and a steel bracket is provided at the lower end of the support insulator.

[0010] Furthermore, the arc extinguishing chamber is connected to a current detection device, and the current detection device includes an insulating sleeve and a detector.

[0011] Furthermore, the arc extinguishing chamber and the capacitor, the capacitor and the nonlinear resistor, and the arc extinguishing chamber and the current detection device are all connected via connecting hardware.

[0012] Beneficial effects: The midpoint DC switch (MBTS) for cutting off a single-ended converter valve of the present invention is a pioneering invention. Through this scheme, the capacitor and the arc extinguishing chamber form a series resonant circuit to oscillate the DC current, and the DC arc that passes through zero is extinguished by the strong air blowing of the arc extinguishing chamber. The current is converted from the capacitor circuit to the nonlinear resistor circuit through the nonlinear resistor connected to both ends of the capacitor, thereby completing the DC current breaking process, and also protecting the capacitor from damage by overvoltage, and enhancing the stability and safety of the DC transmission system. The midpoint DC switch (MBTS) for cutting off a single-ended converter valve of the present invention can act immediately when a converter valve fault is detected, cut off the faulty converter valve from the system, prevent the fault from spreading, and does not affect other normally operating converter valves, effectively improving the overall fault resistance and transmission efficiency of the DC transmission system, and providing a strong guarantee for the safe and stable operation of the DC transmission system.

[0013] The converter station of the present invention provides the following solutions: A converter station comprises a valve group, wherein the valve group comprises a high-voltage end converter valve and a low-voltage end converter valve, wherein one end of the low-voltage end converter valve is connected to a grounding system through a neutral bus switch, and the other end is connected to one end of the high-voltage end converter valve through a midpoint DC switch (MBTS), and the other end of the high-voltage end converter valve is connected to a DC transmission line; the line between the high-voltage end converter valve and the midpoint DC switch (MBTS) is directly connected to the grounding system through a bypass line, and the bypass line is connected in series with the bypass switch; the midpoint DC switch (MBTS) comprises a support bushing, an arc extinguishing chamber arranged on the support bushing, an insulating platform arranged near the support bushing, and a capacitor arranged on the insulating platform, wherein the support bushing and the insulating platform are respectively used to meet the insulation requirements of the arc extinguishing chamber and the capacitor to the ground, the arc extinguishing chamber is connected to the capacitor to form a series resonant circuit, and nonlinear resistors are connected at both ends of the capacitor to avoid damage to the capacitor and the break caused by excessive voltage on the capacitor, and to meet the energy release requirements of the DC system after the DC switch is disconnected, and there are multiple capacitors connected in series and parallel to form a capacitor group.

[0014] Furthermore, a mounting bracket is provided at the lower end of the support sleeve for mounting an operating mechanism of the arc extinguishing chamber, and the operating mechanism is used to drive a pull rod provided in the support sleeve to enable the arc extinguishing chamber to perform opening and closing movements.

[0015] Furthermore, a support insulator is provided below the insulating platform, and the support insulator supports the insulating platform through longitudinal beams and transverse beams provided at the bottom of the insulating platform, and a steel bracket is provided at the lower end of the support insulator.

[0016] Furthermore, the arc extinguishing chamber is connected to a current detection device, and the current detection device includes an insulating sleeve and a detector.

[0017] Furthermore, the arc extinguishing chamber and the capacitor, the capacitor and the nonlinear resistor, and the arc extinguishing chamber and the current detection device are all connected via connecting hardware.

[0018] Beneficial effects: The converter station of the present invention is a pioneering invention. Through this scheme, a midpoint DC switch (MBTS) is installed between the high-voltage converter valve and the low-voltage converter valve. When the converter valve is fault-free, it can withstand the rated operating current of the system and the 400kV pole line operating voltage. When the converter valve fails, the DC current flowing through the faulty converter valve can be disconnected, thereby cutting off the faulty converter valve from the DC system, maintaining the power transmission of the DC system, and not completely or partially shutting down the DC system, thereby reducing the loss of DC transmission power. The capacitor and the arc extinguishing chamber form a series resonant circuit to oscillate the DC current, and the strong air blowing of the arc extinguishing chamber is used to extinguish the zero-crossing DC arc. The current is converted from the capacitor circuit to the nonlinear resistor circuit through the nonlinear resistor connected to both ends of the capacitor, thereby completing the DC current disconnection process, protecting the capacitor from overvoltage damage, and enhancing the stability and safety of the DC transmission system. The midpoint DC switch (MBTS) for cutting off a single-ended converter valve of the present invention can be immediately activated upon detecting a converter valve fault, and cut off the faulty converter valve from the system to prevent the fault from spreading without affecting other normally operating converter valves, thereby effectively improving the overall fault resistance and transmission efficiency of the DC power transmission system, and providing a strong guarantee for the safe and stable operation of the DC power transmission system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a partial circuit diagram of a converter station in the prior art; Figure 2 It is a structural schematic diagram of an embodiment of a midpoint DC switch (MBTS) for cutting off a single-ended converter valve according to the present invention; Figure 3 The invention is an application circuit diagram of a midpoint DC switch (MBTS) for cutting off a single-ended converter valve.

[0020] In the figure: 1. Support bushing; 2. Arc extinguishing chamber; 3. Insulating platform; 4. Capacitor; 5. Nonlinear resistor; 6. Mounting bracket; 7. Operating mechanism; 8. Maintenance platform; 9. Support insulator; 10. Steel bracket; 11. Current detection device; 12. Insulating bushing; 13. Detector; 14. Connecting hardware. DETAILED DESCRIPTION

[0021] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0022] The embodiment of the midpoint DC switch (MBTS) for cutting off the single-ended converter valve of the present invention is: The midpoint DC switch (MBTS) for cutting off a single-ended converter valve of the present invention forms a resonant circuit and utilizes the resonance effect to extinguish the DC arc. At this time, the line voltage increases, and then utilizes the principle that the resistance value of a nonlinear resistor changes with the change of an external voltage to convert the current from the capacitor circuit to the nonlinear resistor circuit, thereby achieving the cutting off of the faulty converter valve from the circuit.

[0023] As a basic solution, Figure 2 As shown, the midpoint DC switch (MBTS) for cutting off a single-ended converter valve of the present invention comprises a support bushing 1, an arc extinguishing chamber 2 arranged on the support bushing 1, an insulating platform 3 arranged near the support bushing 1 and a capacitor 4 arranged on the insulating platform 3; the arc extinguishing chamber 2 is used to quickly extinguish the arc during the opening and closing process to prevent the arc from damaging the switch equipment and ensure the safe cutting off of the current; the capacitor 4 and the arc extinguishing chamber 2 form a series resonant circuit for oscillating the DC current and breaking when the oscillation passes through the zero point, which is helpful to smooth the current change during the opening and closing process of the switch, reduce the current impact, and improve the breaking performance of the switch; the two ends of the capacitor 4 are connected with a nonlinear resistor The device 5 is used to avoid the damage of the capacitor and the break caused by the excessive voltage on the capacitor, and to meet the energy release requirements of the DC system after the DC switch is disconnected. The nonlinear resistor 5 converts the current from the capacitor 4 circuit to the nonlinear resistor 5 circuit, and absorbs and suppresses the overvoltage generated during the switch operation, protecting the capacitor 4 and the arc extinguishing chamber 2 from damage by overvoltage; the insulating platform 3 is the installation base of the capacitor 4 and the nonlinear resistor 5, providing the necessary electrical insulation and mechanical support for the capacitor 4 and the nonlinear resistor 5. The capacitor 4 and the nonlinear resistor 5 are separated from other parts of the switch system by the insulating platform 3, thereby ensuring the electrical safety and stability of the entire system. The support bushing 1, as the supporting structure of the arc extinguishing chamber 2, not only meets the insulation requirements of the arc extinguishing chamber 2 to the ground, but also ensures that the arc extinguishing chamber 2 can remain stable during the opening and closing process; since the capacitor 4 has to withstand the voltage between the breaks of the arc extinguishing chamber 2 and meet the requirements of the voltage rise rate, it is difficult for a single capacitor 4 to meet the requirements, and multiple capacitors 4 are connected in series and parallel to form a capacitor group 4 to meet the withstand voltage requirements of the capacitor 4.

[0024] As a preferred embodiment, the lower end of the support sleeve 1 is provided with a mounting bracket 6 for mounting the operating mechanism 7 of the arc extinguishing chamber 2. The operating mechanism 7 converts the external control signal into mechanical motion to drive the arc extinguishing chamber 2 to perform the opening and closing motion, thereby realizing the precise control of the arc extinguishing chamber 2. Specifically, the operating mechanism 7 drives the pull rod provided in the support sleeve 1 to make the arc extinguishing chamber 2 perform the opening and closing motion. The operating mechanism 7 is the power source of the pull rod. When the operating mechanism 7 is activated, the pull rod reciprocates in the support sleeve 1 to transfer the power to the arc extinguishing chamber 2 to realize the opening and closing motion. At the same time, the support sleeve 1 also provides the necessary support and guiding function for the pull rod. The support sleeve 1 provides the pull rod with a movement space, so that the pull rod can smoothly transfer the power of the operating mechanism 7. The guiding function of the support sleeve 1 ensures the accuracy and stability of the pull rod movement. A maintenance platform 8 can also be set under the operating mechanism to facilitate maintenance personnel to inspect the operating mechanism.

[0025] As a preferred embodiment, a post insulator 9 is provided below the insulating platform 3, and the post insulator 9 supports the insulating platform 3 through the longitudinal beam and the cross beam provided at the bottom of the insulating platform 3, and a steel bracket 10 is provided at the lower end of the post insulator 9. The insulating platform 3 is installed above the post insulator 9, and the stability and safety of the insulating platform 3 and the capacitor 4 and the nonlinear resistor thereon are ensured by the support provided by the post insulator 9. The post insulator 9 is connected to the insulating platform 3 through the longitudinal beam and the cross beam provided at the bottom of the insulating platform 3, and the longitudinal beam and the cross beam constitute the support structure below the insulating platform 3. In other embodiments, the post insulator 9 can be directly connected to the insulating platform 3, but the insulating platform 3 needs to be reinforced or a material with sufficient strength is used to meet the supporting function of the insulating platform 3. A steel bracket 10 is provided at the lower end of the post insulator 9, and the steel bracket 10 is fixed on the ground. The connection between the two needs to be ensured to be firm and reliable, and the steel bracket 10 needs to have sufficient strength and rigidity to withstand various forces and vibrations of the switch system during operation to ensure the overall stability of the system.

[0026] As a preferred embodiment, the arc extinguishing chamber 2 is connected to a current detection device 11, and the current detection device 11 includes an insulating sleeve 12 and a detector 13. The detector 13 is connected to the arc extinguishing chamber 2 through an optical fiber in the insulating sleeve 12. The connection between the two must ensure that the electrical connection is good and does not affect the detection accuracy and detection efficiency of the detector 13. The detector 13 provides important electrical parameter information for the switch system by measuring the current in the arc extinguishing chamber 2, which helps to achieve precise control and protection of the switch. During the operation of the arc extinguishing chamber 2, a high-temperature and high-energy arc will be generated. The arc will damage the detector 13 if it contacts the detector 13. The insulating sleeve 12 can maintain a certain safety distance between the detector 13 and the arc extinguishing chamber 2, and also ensure the safe isolation of the optical fiber in the insulating sleeve 12 and the arc extinguishing chamber 2.

[0027] As a preferred embodiment, the arc extinguishing chamber 2 and the capacitor 4, the capacitor 4 and the nonlinear resistor 5, and the arc extinguishing chamber 2 and the current detection device 11 are all connected by connecting fittings 14. The connecting fittings 14 ensure the electrical connection and mechanical fixation between the components, so that the entire switch system can form a stable and reliable whole. The connecting fittings 14 are usually required to have high strength, good conductivity and corrosion resistance to meet the long-term operation requirements of the switch system.

[0028] The specific working process of this embodiment is as follows: the capacitor 4 forms a series resonant circuit with the inductance of the line and the DC arc generated in the arc extinguishing chamber 2, so that the arc in the arc extinguishing chamber 2 generates an oscillation of the current amplitude in the loop due to the resonance of the circuit. After receiving the signal, the operating mechanism 7 drives the connecting rod to push the moving and static contacts of the arc extinguishing chamber 2 to open. After opening, a DC arc is generated. Due to instability and negative resistance effect, the generated DC arc begins to oscillate under the action of the resonant circuit. When the oscillation point reaches the zero point position, the DC arc that crosses zero is extinguished by strong air blowing in the arc extinguishing chamber 2. After the DC arc successfully crosses zero and is disconnected, the voltage on the capacitor 4 will continue to rise. At this time, under the action of the nonlinear resistor 5 connected in parallel at both ends of the capacitor 4 for limiting overvoltage, the current is converted from the capacitor 4 loop to the nonlinear resistor 5 loop, thereby completing the disconnection process of the DC current.

[0029] The specific application process of the midpoint DC switch (MBTS) for cutting off the single-ended converter valve of the present invention is as follows: Figure 3As shown, the midpoint DC switch (MBTS) for cutting off the single-end converter valve of the present invention is installed between the high-voltage converter valve and the low-voltage converter valve in the valve group. One end of the low-voltage converter valve is connected to the grounding system outside the converter station through the neutral bus switch, and the other end is connected to the midpoint DC switch (MBTS); one end of the high-voltage converter valve is connected to the midpoint DC switch (MBTS), and the other end is connected to the DC transmission line. When the valve group works normally, the midpoint DC switch (MBTS) is closed, one end of the low-voltage converter valve is connected to the grounding system outside the converter station through the neutral bus switch, and the low-voltage converter valve and the high-voltage converter valve transmit power to the opposite end through the DC transmission line. When a low-voltage converter valve of a valve group fails, the bypass switch on the bypass circuit is closed, and the low-voltage converter valve is bypassed from the circuit, and the neutral bus switch and midpoint DC switch (MBTS) connected to the faulty valve group are disconnected, thereby cutting off the faulty valve; the high-voltage converter valve and other valve groups in the valve group continue to work normally, and one end of the high-voltage converter valve is connected to the grounding system outside the converter station through the bypass, and the other end continues to connect to the DC transmission line to work normally. When the grounding system outside the converter station fails, temporary in-station grounding can be achieved by closing the neutral bus grounding switch to ensure the safety of the DC transmission system.

[0030] The embodiment of the converter station of the present invention is: The converter station of the present invention includes a valve group, which includes a high-pressure end converter valve and a low-pressure end converter valve. One end of the low-pressure end converter valve is connected to the grounding system through a neutral bus switch, and the other end is connected to one end of the high-pressure end converter valve through a midpoint DC switch (MBTS). The other end of the high-pressure end converter valve is connected to a DC transmission line. The line between the high-pressure end converter valve and the midpoint DC switch (MBTS) is directly connected to the grounding system through a bypass line, and a bypass switch is connected in series on the bypass line. The embodiment of the midpoint DC switch (MBTS) has been described in the previous text and will not be repeated here.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A midpoint DC switch (MBTS) for cutting off a single-ended converter valve, characterized in that: It includes a support bushing, an arc extinguishing chamber arranged on the support bushing, an insulating platform arranged near the support bushing and a capacitor arranged on the insulating platform. The support bushing and the insulating platform are respectively used to meet the insulation requirements of the arc extinguishing chamber and the capacitor to the ground. The arc extinguishing chamber is connected with the capacitor to form a series resonant circuit. Nonlinear resistors are connected at both ends of the capacitor to avoid damage to the capacitor and the fracture caused by excessive voltage on the capacitor and meet the energy release requirements of the DC system after the DC switch is disconnected. There are multiple capacitors connected in series and parallel to form a capacitor group.

2. The midpoint DC switch (MBTS) for cutting off a single-ended converter valve according to claim 1, characterized in that: A mounting bracket is provided at the lower end of the support sleeve for mounting an operating mechanism of the arc extinguishing chamber, and the operating mechanism is used to drive a pull rod provided in the support sleeve to enable the arc extinguishing chamber to perform opening and closing movements.

3. The midpoint DC switch (MBTS) for cutting off a single-ended converter valve according to claim 1, characterized in that: A support insulator is arranged below the insulating platform. The support insulator supports the insulating platform through longitudinal beams and transverse beams arranged at the bottom of the insulating platform. A steel bracket is arranged at the lower end of the support insulator.

4. The midpoint DC switch (MBTS) for cutting off a single-ended converter valve according to any one of claims 1 to 3, characterized in that: The arc extinguishing chamber is connected with a current detection device, and the current detection device comprises an insulating sleeve and a detector.

5. The midpoint DC switch (MBTS) for cutting off a single-ended converter valve according to any one of claims 1 to 3, characterized in that: The arc extinguishing chamber and the capacitor, the capacitor and the nonlinear resistor, and the arc extinguishing chamber and the current detection device are all connected through connecting hardware.

6. A converter station, comprising a valve group, the valve group comprising a high-pressure end converter valve and a low-pressure end converter valve, characterized in that: One end of the low-voltage converter valve is connected to the grounding system through a neutral bus switch, and the other end is connected to one end of the high-voltage converter valve through a midpoint DC switch (MBTS), and the other end of the high-voltage converter valve is connected to a DC transmission line; the line between the high-voltage converter valve and the midpoint DC switch (MBTS) is directly connected to the grounding system through a bypass line, and the bypass line is connected in series with a bypass switch; the midpoint DC switch (MBTS) includes a support bushing, an arc extinguishing chamber arranged on the support bushing, an insulating platform arranged close to the support bushing, and a capacitor arranged on the insulating platform, the support bushing and the insulating platform are respectively used to meet the insulation requirements of the arc extinguishing chamber and the capacitor to the ground, the arc extinguishing chamber is connected to the capacitor to form a series resonant circuit, and nonlinear resistors are connected at both ends of the capacitor to avoid damage to the capacitor and the break caused by excessive voltage on the capacitor, and to meet the energy release requirements of the DC system after the DC switch is disconnected, and there are multiple capacitors connected in series and parallel to form a capacitor bank.

7. The converter station according to claim 6, characterized in that: A mounting bracket is provided at the lower end of the support sleeve for mounting an operating mechanism of the arc extinguishing chamber, and the operating mechanism is used to drive a pull rod provided in the support sleeve to enable the arc extinguishing chamber to perform opening and closing movements.

8. The converter station according to claim 6, characterized in that: A support insulator is arranged below the insulating platform. The support insulator supports the insulating platform through longitudinal beams and transverse beams arranged at the bottom of the insulating platform. A steel bracket is arranged at the lower end of the support insulator.

9. The converter station according to any one of claims 6 to 8, characterized in that: The arc extinguishing chamber is connected with a current detection device, and the current detection device comprises an insulating sleeve and a detector.

10. The converter station according to any one of claims 6 to 8, characterized in that: The arc extinguishing chamber and the capacitor, the capacitor and the nonlinear resistor, and the arc extinguishing chamber and the current detection device are all connected through connecting hardware.

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