CN108519545B - High-voltage insulator surface flashover experimental device and method under extremely cold condition - Google Patents

Abstract

An experimental device and method for flashover along the surface of a high-voltage insulator under extremely cold conditions belong to the technical field of high-voltage equipment experiments. The device comprises a closed air chamber, a first conducting rod, an equalizing ring, a protection resistor, a high-voltage power supply, a measuring device, a first low-temperature refrigerating device, a second low-temperature refrigerating device, a resistance-capacitance divider and a high-voltage digital voltmeter.

Description

An experimental device and method for surface flashover of high-voltage insulators under extremely cold conditions

technical field

The invention relates to the technical field of high-voltage equipment experiments, in particular to a high-voltage insulator surface flashover test device and method under extremely cold conditions.

Background technique

GIS/GIL equipment has been applied since the 1960s and 1970s and has been widely used all over the world, and has great application prospects in the fields of UHV power transmission and offshore large-scale wind power transmission. However, GIS/GIL is a composite insulation system composed of solid medium and gas medium, and the internal gas-solid interface is the weakest part of the insulation of the whole system. Under the action of a certain external voltage, the surface discharge at the gas-solid interface inside the GIS/GIL often occurs first; with the increase of the pressure amplitude and time, the surface discharge at the gas-solid interface may develop into a penetrating breakdown, resulting in flashover along the surface, affecting the normal operation of the equipment, and even leading to insulation accidents. Therefore, it is of great significance to study the flashover characteristics of the dielectric gas-solid interface for improving the reliability of gas-insulated electrical equipment.

my country has a vast territory, and the climate varies greatly from place to place. There are extremely cold regions in the northeast and northwest of my country, and the lowest temperature in winter can be as low as below -40°C for a long time. It is inevitable for electrical equipment to operate in extremely cold regions. In order to ensure the reliability of power supply, the insulation materials used in electrical equipment must be able to meet the requirements of long-term reliable operation of the equipment in extremely cold environments. Under the extremely cold conditions of GIS/GIL, there will be subzero temperature inside, resulting in non-uniform temperature distribution of gas and insulators, and a temperature difference will be formed between the guide rod and the shell, which will increase with the increase of current. Under extremely cold conditions, the temperature inside the GIS/GIL equipment will cause the temperature on the surface of the insulator to change, thereby changing the volume conductivity, surface conductivity and dielectric constant of the insulator, further affecting the insulation performance of the insulator and causing the insulator to surface. Flashover. At present, there are few studies on the electrical properties of insulating materials in extremely cold regions in my country. It is not clear how the mechanical and electrical properties of insulating materials change under low temperature conditions. In order to ensure the safe and reliable operation of electrical equipment in extremely cold regions, the insulation materials The electrical performance research under extremely cold conditions has important practical significance, so it is urgent to carry out experimental research on surface flashover of high-voltage insulators under extremely cold conditions.

At present, there are still many deficiencies in the high-voltage insulator surface flashover test device, only the heating device does not have a low-temperature cooling device, which cannot simulate the actual working conditions of GIS under extremely cold conditions, and when the experiment is carried out in a completely closed large air chamber, The amount of gas used is large and the flashover test under different air pressure and gas composition conditions cannot be realized. The flashover material is fixed and cannot be replaced. Experiments under such voltage conditions do not have certain versatility.

Contents of the invention

In order to solve the problems existing in the prior art, the present invention has certain versatility, and the present invention adopts the mixed solution of deionized water and ethylene glycol, referred to as ethylene glycol aqueous solution, as a low-temperature circulating fluid for the electrodes at both ends of the flashover insulator. Cooling is used to simulate various conditions when operating under extremely cold conditions. As a low-temperature circulating fluid, ethylene glycol aqueous solution has an insulating effect, ensuring the insulation when flowing through the high-voltage hollow electrode.

The invention provides a high-voltage insulator surface flashover test device under extremely cold conditions. The device includes a closed air chamber, a first conductive rod and a voltage equalizing ring, a protection resistor, a high-voltage power supply, a measuring device, the first low-temperature refrigeration equipment, and the second 2. Low-temperature refrigeration equipment, resistance-capacitance divider and high-voltage digital voltmeter. One end of the high-voltage power supply is grounded, and the other end is connected to a protective resistor and a voltage equalizing ring in turn. Grounding, the output terminal is connected to a high-voltage digital voltmeter;

The side wall of the closed air chamber is a hollow cylinder, the bottom opening of the hollow cylinder is riveted with a bottom cover, and the bottom cover is grounded, and a sealing insulator is fixed and sealed at the upper port of the hollow cylinder, so The center of the sealing insulator is plugged with a first conductive rod, and the top end of the first conductive rod is sleeved with a pressure equalizing ring,

The measuring device a includes a hollow electrode, a first pressure equalizing cover, a flashover insulator, a cryogenic fluid circulation cylinder, a second pressure equalizing cover, a second conductive rod and a third pressure equalizing cover, and the bottom end of the hollow electrode is fixed A first equalizing cover is installed, the top of the hollow electrode is screwed to the first conductive rod, the lower end of the first equalizing cover is closely attached to the upper surface of the high-voltage end in the middle of the flashover insulator, and the low-voltage end of the flashover insulator is fixedly connected to the round On the inner wall of the barrel, the lower surface of the high-voltage end in the middle of the flashover insulator is sequentially connected to the second equalizing cover, the second conductive rod and the third equalizing cover;

The bottom end of the cylinder is screwed with a support rod, and the lower end of the support rod is welded to the upper surface of the bottom cover plate. The connection between the cylinder and the low-voltage end of the flashover insulator is screwed with a circular hollow ring, and the A low-temperature fluid inlet pipe and a low-temperature fluid outlet pipe are inserted on the outer wall of the circular hollow ring, and the ends of the low-temperature fluid inlet pipe and the low-temperature fluid outlet pipe pass through the bottom cover plate and are connected to the second low-temperature refrigeration device;

Two upper and lower screw holes are opened on the outer wall of the hollow electrode, which are respectively screwed with a high-temperature fluid inlet pipe and a high-temperature fluid outlet pipe. An opening is provided on the side wall of the hollow cylinder, and the opening is plugged with a sealing cover plate For sealing, two horizontal outlet through-holes are opened on the sealing cover, and the high-temperature fluid inlet pipe and the high-temperature fluid outlet pipe are respectively exported to their respective ends through the two outlet through-holes, and the high-temperature fluid inlet pipe and the high-temperature fluid outlet The ends of the outlet pipes are all connected to the first low-temperature refrigeration equipment;

The bottom cover plate is provided with an inflation hole, and an inflation tube is plugged into the hole;

The inner wall of the first low-temperature refrigeration equipment is fixedly installed with a high-temperature fluid tank, the high-temperature fluid tank includes a first water pump and a first temperature sensor, and the first water pump is fixedly connected to the high-temperature fluid inlet pipe, and the first temperature sensor is fixedly connected to the high-temperature fluid Out of the tube;

The inner wall of the second low-temperature refrigeration equipment is fixedly installed with a low-temperature fluid tank, the low-temperature fluid tank includes a second water pump and a second temperature sensor, and the second water pump is fixedly connected to the low-temperature fluid inlet pipe, and the second temperature sensor is fixedly connected to the low-temperature fluid Out of the tube;

The fluid in the high-temperature fluid box and the low-temperature fluid box is a mixture of deionized water and ethylene glycol.

A valve is fixedly installed on the outer wall of the inflation tube.

A surface flashover test method for high-voltage insulators under extreme cold conditions, which is realized by using the high-voltage insulator surface flashover test device under extreme cold conditions according to claim 1, characterized in that the method includes:

Step 1. Vacuumize the air in the closed air chamber, and fill the closed air chamber with gas with a certain pressure, and install the structure in the closed air chamber at the same time, so that the hollow electrode and the high-temperature fluid inlet pipe and high-temperature fluid outlet pipe Connect the flashover insulator to the inner wall of the cylinder, and add defect factors affecting the flashover voltage of the insulator to the flashover insulator;

Step 2. Set the temperature of the high-temperature fluid tank and the low-temperature fluid tank on the first low-temperature refrigeration equipment and the second low-temperature refrigeration equipment respectively. Refrigerating, while using the first temperature sensor and the second temperature sensor to monitor the temperature in the high-temperature fluid tank and the low-temperature fluid tank respectively, when the temperature is higher than the preset value, the first temperature sensor and the second temperature sensor send a refrigeration signal, when When the temperature reaches a preset value, the first temperature sensor and the second temperature sensor transmit temperature signals to the first low-temperature refrigeration device and the second low-temperature refrigeration device respectively, so that the high-temperature fluid tank and the low-temperature fluid tank stop cooling;

Step 3. Turn on the first water pump and the second water pump, and continuously input the ethylene glycol aqueous solution into the hollow electrode to cool the high-voltage end and low-voltage end of the flashover insulator. After the temperature of the electrode of the flashover insulator is stable, use automatic boost Apply voltage to both ends of the flashover insulator by using the method, and monitor the voltage at both ends of the flashover insulator in real time with a high-voltage digital meter;

Step 4. After the flashover insulator flashover, measure and record the flashover voltage, and immediately reduce the high voltage power supply to zero;

Step 5, turn off the first low-temperature refrigeration equipment, the second low-temperature refrigeration equipment, the first water pump, and the second water pump in sequence;

Step 6. Discharging the RC voltage divider;

Step 7. After the temperature of the two ends of the flashover insulator and the hollow electrode returns to normal temperature, disassemble the closed air chamber, observe the traces on the surface of the flashover insulator due to flashover discharge at the defect, and take pictures to confirm the occurrence of flashover along the surface at the defect;

Step 8. Dispose of the traces on the surface of the flashover insulator, then wipe it with absolute ethanol, and then repeat step to step for the next experiment.

The automatic step-up method is based on whether the high-voltage end and low-voltage end of the flashover insulator are at the required temperature. If the temperature of the high-voltage end and low-voltage end of the flashover insulator is not the required temperature, the external transformer is adjusted to stop feeding the two voltages of the flashover insulator. When the high-voltage end and low-voltage end of the flashover insulator meet the required temperature, adjust the external transformer to pressurize the high-voltage end and low-voltage end of the flashover insulator to judge whether the flashover insulator has flashover. If the flashover insulator does not Flashover, then continue to flashover the temperature of the high-voltage end and low-voltage end of the insulator.

Beneficial effects: the present invention can save the consumption of various gases by adopting a smaller closed air chamber, on the other hand, it is easy to install, and can realize flashover experiments under different air pressure and gas composition conditions, including environmental protection gases and other new types of gases. flashover test, and the present invention is applicable to various voltage conditions such as AC, DC, and impact, and the electric insulator model for flashover can increase experimental conditions, such as roughness, surface characteristics, metal particles, etc., so the present invention has certain Versatility, and the present invention uses ethylene glycol aqueous solution as the low-temperature circulating fluid to cool the high-voltage end and low-voltage end of the flashover insulator, while realizing the temperature gradient, it is used to simulate various situations under extremely cold conditions, ethylene glycol As a low-temperature circulating fluid, the alcohol aqueous solution has the function of insulation, which ensures the insulation when flowing through the high-voltage hollow electrode, and protects other facilities such as water pumps, and the low-temperature refrigeration equipment is located outside the closed air chamber, which greatly reduces the impact on the experiment. At the same time, since the boiling point of ethylene glycol is 197.3°C, the device can also perform surface flashover tests of insulators under high temperature conditions.

Description of drawings

Fig. 1 is the structural representation of the high-voltage insulator flashover test device along the surface under extremely cold conditions of the present invention;

Fig. 2 is the structural representation of measuring device in Fig. 1 of the present invention;

Fig. 3 is a schematic diagram of the oil flow in the circular hollow ring of the high-voltage insulator flashover test device along the surface under extremely cold conditions of the present invention;

Fig. 4 is a voltage regulation flow chart of the automatic voltage regulation method of the surface flashover test device for high voltage insulators under extremely cold conditions of the present invention.

In the figure: 1. Closed gas chamber, 2. Sealed insulator, 3. First conductive rod, 4. Pressure equalizing ring, 5. Hollow electrode, 6. First pressure equalizing cover, 7. High temperature fluid inlet pipe, 8. High temperature Fluid outlet pipe, 9, high-temperature fluid tank, 901, first water pump, 902, first temperature sensor, 10, first low-temperature refrigeration equipment, 11, hollow cylinder, 12, sealing cover plate, 13, bottom cover plate, 14 , inflation hole, 15, inflation pipe, 16, air valve, 17, low temperature fluid inlet pipe, 18, low temperature fluid inlet pipe, 19, low temperature fluid tank, 1901, second water pump, 1902, second temperature sensor, 20, the first Two low-temperature refrigeration equipment, 21. Support rod, 22. Cylinder, 23. Round hollow ring, 24. Flashover insulator, 25. Second pressure equalizing cover, 26. Second conductive rod, 27. Third pressure equalizing cover , 28, protective resistor, 29, high-voltage power supply, 30, RC voltage divider, 31, high-voltage digital meter, a, measuring device.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the invention in conjunction with the accompanying drawings in the embodiments of the invention,

As shown in Figure 1, the present invention provides a high-voltage insulator surface flashover experimental device under extremely cold conditions. device a, the first low-temperature refrigeration equipment 10, the second low-temperature refrigeration equipment 20, the resistance-capacity voltage divider 30 and the high-voltage digital voltmeter 31, and the first low-temperature refrigeration equipment 10 and the second low-temperature refrigeration equipment 20 can freely set the temperature range, The digital display shows that the resistance-capacitance voltage divider 30 is a general-purpose high-voltage measuring instrument, which can be used in electric power systems, electrical appliances, and electronic equipment manufacturing departments to measure power frequency AC high voltage and DC high voltage. It is composed of a high-voltage measuring part and a low-voltage display instrument, and the high-voltage digital meter 31 is used together with the resistance-capacitance divider 30. It has the advantages of convenient use, intuitive display, and high measurement accuracy. One end of the high-voltage power supply 29 is grounded, and the other end is in turn Connect the protective resistor 28 and the voltage equalizing ring 4, the high voltage end of the RC voltage divider 30 is connected to the voltage equalizing ring 4, the ground end is grounded, and the output end is connected to a high voltage digital voltmeter 31;

As shown in Figure 2, the side wall of the closed air chamber 1 is a hollow cylinder 11, the lower opening of the hollow cylinder 11 is riveted with a bottom cover 13, and the bottom cover 13 is grounded, the hollow cylinder 11 The upper port is fixed and sealed with a sealing insulator 2, and the center of the sealing insulator 2 is inserted with a first conductive rod 3, and the top end of the first conductive rod 3 is sleeved with a pressure equalizing ring 4;

The measuring device a includes a hollow electrode 5, a first pressure equalizing cover 6, a flashover insulator 24, a cryogenic fluid circulation cylinder 22, a second pressure equalizing cover 25, and the first pressure equalizing cover 6 and the second pressure equalizing cover 25 The material is aluminum material, which can make the voltage evenly distributed on the high voltage side of the flashover insulator 24, the second conductive rod 26 and the third voltage equalizing cover 27, the top of the hollow electrode 5 is screwed to the first conductive rod 3, and the The bottom end of the hollow electrode 5 is fixedly equipped with a first equalizing cover 6, and the lower end of the first equalizing cover 6 is closely attached to the upper surface of the high-voltage end in the middle of the flashover insulator 24, and the low-voltage end of the flashover insulator 24 is fixedly connected to the cylinder 22 On the inner wall of the flashover insulator 24, the lower surface of the middle high-voltage end of the flashover insulator 24 is sequentially connected to the second equalizing cover 25, the second conductive rod 26 and the third equalizing cover 27;

The bottom end of the cylinder 22 is screwed with a support rod 21, and the lower end of the support rod 21 is welded to the upper surface of the bottom cover plate 13, and the connection between the cylinder 22 and the low-voltage end of the flashover insulator 24 is screwed with a circular hollow ring 23 , as shown in Figure 3, and on the outer wall of the circular hollow ring 23 at the joint, a cryogenic fluid inlet pipe 17 and a cryogenic fluid outlet pipe 18 are inserted, and both the cryogenic fluid inlet pipe 17 and the cryogenic fluid outlet pipe 18 are made of PTFE Composed of hard tubes made of materials, it can withstand the temperature of -60°C to +260°C, which is in line with the working temperature of our cryogenic fluid -40°C to 0°C. The ends of the cryogenic fluid inlet pipe 17 and the cryogenic fluid outlet pipe 18 pass through the bottom The cover plate 13 is connected to the second low-temperature refrigeration device 20;

The outer wall of the hollow electrode 5 is provided with two upper and lower screw holes, which are respectively screwed with a high-temperature fluid inlet pipe 7 and a high-temperature fluid outlet pipe 8, which conforms to the law of fluid flow and facilitates the fluid to cool the hollow electrode. The high-temperature fluid inlet pipe 7 and the high-temperature fluid outlet pipe 8 are made of hard tube made of PTFE, which can withstand the temperature of -60 ° C ~ +260 ° C, which is in line with the working temperature of our high-temperature fluid -20 ~ 0 ° C. PTFE can ensure that the high-voltage electrode and the hollow cylinder The cylinder 11 is insulated, and can ensure that the high-temperature fluid inlet pipe 7 and the high-temperature fluid outlet pipe 8 are not deformed and can be bent within a certain range during vacuuming. The side wall of the hollow cylindrical cylinder 11 is provided with an opening, which is inserted through the connected to the sealing cover plate 12 for sealing, the sealing cover plate 12 is provided with two horizontal lead-out through-holes, and the high-temperature fluid inlet pipe 7 and the high-temperature fluid outlet pipe 8 are led out of their respective ends through the two lead-out through-holes, so The ends of the high-temperature fluid inlet pipe 7 and the high-temperature fluid outlet pipe 8 are connected to the first low-temperature refrigeration device 10;

The bottom cover plate 13 is provided with an inflation hole 14, and an inflation tube 15 is plugged into the hole;

The inner wall of the first low-temperature refrigeration device 10 is fixed with a high-temperature fluid box 9, and the high-temperature fluid box 9 is made of polycarbonate PC plastic, which has the characteristics of convenient handling, easy processing, and high temperature resistance, and the working temperature is -20 ~ 0 °C, placing the high-temperature fluid tank 9 in the first low-temperature refrigeration equipment 10 can ensure that the impact of the first low-temperature refrigeration equipment 10 on the experimental results is minimized, and the high-temperature fluid tank 9 includes a first water pump 901 and a first temperature sensor 902, so The first temperature sensor 902 is mainly composed of a thermistor, and the thermistor is composed of metal oxide ceramics, which is a low-cost, high-sensitivity temperature sensor. The temperature measurement range: the temperature range is about -50 to 200 degrees, It meets the design requirements, and has the advantages of small size and fast response time, and the first water pump 901 is fixedly connected to the high-temperature fluid inlet pipe 7, and the first temperature sensor 902 is fixedly connected to the high-temperature fluid outlet pipe 8;

A low-temperature fluid box 19 is fixedly installed on the inner wall of the second low-temperature refrigeration device 20, and the low-temperature fluid box 19 is also made of polycarbonate PC plastic, and the low-temperature fluid box 19 includes a second water pump 1901 and a second temperature sensor 1902. The second temperature sensor 1902 is also composed of a thermistor, and the second water pump 1901 is fixedly connected to the low-temperature fluid inlet pipe 17, and the second temperature sensor 1902 is fixedly connected to the low-temperature fluid outlet pipe 18;

The fluid in the high-temperature fluid box 9 and the low-temperature fluid box 19 is a mixture of deionized water and ethylene glycol, wherein the concentration of ethylene glycol is 60%, and its freezing point temperature can reach -48.3°C. The boiling point of alcohol can reach 197.3°C. This device can also carry out flashover tests of insulators along the surface under high temperature conditions. At the same time, the ethylene glycol aqueous solution has the function of insulation as a low-temperature circulating fluid.

The experimental method of a high-voltage insulator surface flashover experimental device under extremely cold conditions in the present invention includes:

Step 1. Vacuumize the air in the closed air chamber 1, and fill the closed air chamber 1 with gas with a certain pressure to check the airtightness of the device. At the same time, install the structure in the closed air chamber 1 so that The hollow electrode 5 is connected to the high-temperature fluid inlet pipe 7 and the high-temperature fluid outlet pipe 8 to ensure that the interface between the fluid inlet and outlet pipe, the hollow electrode 5 and the circular hollow groove 23 is not leaking, and the flashover insulator 24 is attached to the cylinder 22 inner wall, and add defect factors affecting the flashover voltage of the insulator on the flashover insulator 24;

Step 2, vacuumize the device and fill it with experimental gas, and set the temperature of the high-temperature fluid box 9 and the low-temperature fluid box 19 on the first low-temperature refrigeration equipment 10 and the second low-temperature refrigeration equipment 20 respectively, and set the temperature of the high-temperature fluid box 9 The temperature of the low-temperature fluid box 19 is set at -40-0°C, and the first low-temperature refrigeration equipment 10 and the second low-temperature refrigeration equipment 20 are located outside the closed air chamber 1, so as to reduce the influence on the experiment. It is easy to operate and control. After setting, turn on the refrigeration mode to cool the ethylene glycol aqueous solution in the high-temperature fluid box 9 and the low-temperature fluid box 19. At the same time, the first temperature sensor 902 and the second temperature sensor 1902 are used to monitor the high temperature respectively. The temperature in the fluid box 9 and the low-temperature fluid box 19, when the temperature is higher than the set temperature, the first temperature sensor 902 and the second temperature sensor 1902 send a refrigeration signal, when the temperature reaches the set temperature, the first temperature sensor 902 and the second The temperature sensor 1902 transmits temperature signals to the first low-temperature refrigeration device 10 and the second low-temperature refrigeration device 20 respectively, so that the high-temperature fluid tank 9 and the low-temperature fluid tank 19 stop cooling, thereby ensuring that the high-temperature fluid tank 9 and the low-temperature fluid tank 19 contain two The temperature of the aqueous alcohol solution is the temperature we need. So as to realize the measurement of high-voltage insulator flashover experiment along the surface under extremely cold conditions;

Step 3. Turn on the first water pump 901 and the second water pump 1901, continuously input the ethylene glycol aqueous solution into the hollow electrode, cool the high-voltage end and the low-voltage end of the flashover insulator 24, and monitor the high-temperature fluid tank 9 and the low-temperature fluid tank 19 in real time The temperature of the ethylene glycol aqueous solution in the water and the working status of the first water pump 901 and the second water pump 1901, after the electrode temperature of the flashover insulator 24 is stabilized, the voltage is applied to both ends of the flashover insulator 24 by the automatic boost method, and the digital high voltage is used to The digital meter 31 monitors the voltage at both ends of the flashover insulator 24 in real time;

Step 4. After the flashover insulator 24 flashes over, measure and record the flashover voltage, and immediately reduce the high voltage power supply 29 to zero;

Step 5, turn off the first low-temperature refrigeration equipment 10, the second low-temperature refrigeration equipment 20, the first water pump 901, and the second water pump 1901 in sequence;

Step 6, discharging the RC voltage divider 30;

Step 7. After the temperature of both ends of the flashover insulator 24 and the hollow electrode 5 returns to normal temperature, disassemble the closed air chamber 1, observe the traces on the surface of the flashover insulator 24 due to flashover discharge at the defect, and take pictures to confirm Flashover along the surface occurs at the defect;

Step 8. Remove the traces on the surface of the flashover insulator, wipe it with absolute ethanol, and then repeat steps 1 to 7 for the next experiment.

As shown in Figure 4, the automatic step-up method is based on whether the high-voltage end and the low-voltage end of the flashover insulator 24 are the required temperature, if the temperature of the high-voltage end and the low-voltage end of the flashover insulator 24 is not the required temperature, the external transformer is adjusted to stop Apply pressure to both ends of the flashover insulator 24, when the high voltage end and low voltage end of the flashover insulator 24 are at the required temperature, adjust the external transformer to pressurize the high voltage end and low voltage end of the flashover insulator 24, and judge the flashover insulator 24 Whether flashover occurs, if the flashover insulator 24 does not flashover, then continue to flashover the temperature of the high voltage end and the low voltage end of the insulator 24.

Working principle: the present invention establishes a closed air chamber 1, and installs the first low-temperature refrigeration device 10 on the outer wall of the hollow electrode 5 and the second low-temperature refrigeration device 20 on the outer wall of the cylinder 22, and installs the first low-temperature refrigeration device 20 on the outer wall of the cylinder 22. The high-temperature fluid tank 9 and the low-temperature fluid tank 19 in the refrigeration equipment 10 and the second low-temperature refrigeration equipment 20 heat the fluid ethylene glycol aqueous solution so that it reaches a preset temperature through the first temperature sensor 902 and the second temperature sensor 1902, Now turn on the first water pump 901 and the second water pump 902 to cool the low-voltage end of the flashover insulator 24. The voltage drop at the terminal is zero, and the first low-temperature refrigeration equipment 10, the second low-temperature refrigeration equipment 20, the first water pump 901 and the second water pump 1901 are turned off at the same time, and then the flashover insulator 24 is discharged by the resistance-capacitance divider 30, and the After the temperature of the high-voltage end and low-voltage end of the flashover insulator 24 and the hollow electrode 5 return to normal temperature, disassemble the closed air chamber 1, observe the traces on the surface of the flashover insulator 24 due to flashover discharge at the defect, and take pictures to determine Flashover along the surface occurs at the defect.

Claims (4)

1. A high-voltage insulator surface flashover experimental device under extremely cold conditions, characterized in that: the device includes a closed air chamber (1), a first conductive rod (3) and a voltage equalizing ring (4), a protective resistor (28) , high-voltage power supply (29), measuring device (a), the first low-temperature refrigeration equipment (10), the second low-temperature refrigeration equipment (20), resistance-capacitance voltage divider (30) and high-voltage digital voltmeter (31), described One end of the high-voltage power supply (29) is grounded, and the other end is connected to the protective resistor (28) and the voltage equalizing ring (4) in turn, the high voltage end of the resistance-capacitance voltage divider (30) is connected to the voltage equalizing ring (4), and the grounding end is grounded. The output end is connected with a high-voltage digital voltmeter (31); The side wall of the closed air chamber (1) is a hollow cylinder (11), the bottom opening of the hollow cylinder (11) is riveted with a bottom cover (13), and the bottom cover (13) is grounded, so The upper port of the hollow cylinder (11) is fixed and sealed with a sealing insulator (2), and the center of the sealing insulator (2) is inserted with a first conductive rod (3), and the first conductive rod (3) ) is sleeved with a pressure equalizing ring (4), The measuring device (a) includes a hollow electrode (5), a first pressure equalizing cover (6), a high voltage insulator (24), a low temperature fluid circulation cylinder (22), a second pressure equalizing cover (25), a second conductive Rod (26) and the third pressure equalizing cover (27), the top end of the hollow electrode (5) is screwed to the first conductive rod (3), and the bottom end of the hollow electrode (5) is fixedly installed with the first voltage equalizing cover (27). Cover (6), the lower end of the first equalizing cover (6) is closely attached to the upper surface of the high-voltage end of the middle part of the high-voltage insulator (24), and the low-voltage end of the high-voltage insulator (24) is fixedly connected to the inner wall of the cylinder (22). The lower surface of the middle high-voltage end of the insulator (24) is sequentially connected to the second equalizing cover (25), the second conductive rod (26) and the third equalizing cover (27); The bottom end of the cylinder (22) is screwed with a support rod (21), and the lower end of the support rod (21) is welded to the upper surface of the bottom cover plate (13). The cylinder (22) and the high-voltage insulator (24) The connection of the low-pressure end is screwed with a circular hollow ring (23), and a low-temperature fluid inlet pipe (17) and a low-temperature fluid outlet pipe (18) are inserted on the outer wall of the circular hollow ring (23) at the connection, so The ends of the low-temperature fluid inlet pipe (17) and the low-temperature fluid outlet pipe (18) pass through the bottom cover plate (13) and are connected with the second low-temperature refrigeration equipment (20); The outer wall of the hollow electrode (5) is provided with two upper and lower screw holes, which are respectively screwed with a high-temperature fluid inlet pipe (7) and a high-temperature fluid outlet pipe (8), and on the side wall of the hollow cylinder (11) An opening is provided, and the opening is sealed by inserting a sealing cover (12), and two horizontal outlet through holes are opened on the sealing cover (12), and the high-temperature fluid inlet pipe (7) and the high-temperature fluid outlet pipe (8) leading out respective ends through two leading-out through holes respectively, and the ends of the high-temperature fluid inlet pipe (7) and the high-temperature fluid outlet pipe (8) are all connected to the first low-temperature refrigeration device (10); An inflation hole (14) is opened on the bottom cover plate (13), and an inflation tube (15) is plugged into the hole; A high-temperature fluid tank (9) is fixedly installed on the inner wall of the first low-temperature refrigeration device (10), and the high-temperature fluid tank (9) includes a first water pump (901) and a first temperature sensor (902), and the first water pump (901) is fixedly connected to the high-temperature fluid inlet pipe (7), and the first temperature sensor (902) is fixedly connected to the high-temperature fluid outlet pipe (8); A low-temperature fluid box (19) is fixedly installed on the inner wall of the second low-temperature refrigeration device (20), and the low-temperature fluid box (19) includes a second water pump (1901) and a second temperature sensor (1902), and the second water pump (1901) is fixedly connected to the low-temperature fluid inlet pipe (17), and the second temperature sensor (1902) is fixedly connected to the low-temperature fluid outlet pipe (18); The fluid in the high-temperature fluid box (9) and the low-temperature fluid box (19) is a mixed solution of deionized water and ethylene glycol. 2. A surface flashover test device for high-voltage insulators under extremely cold conditions according to claim 1, characterized in that a valve (16) is fixedly installed on the outer wall of the gas-filled tube (15). 3. An experimental method for surface flashover of high-voltage insulators under extremely cold conditions, which is realized by adopting the experimental device for surface flashover of high-voltage insulators under extremely cold conditions according to claim 1, wherein the method comprises: Step 1. Vacuumize the air in the closed air chamber (1), fill the closed air chamber (1) with gas with a certain pressure, and install the structure in the closed air chamber (1) at the same time, so that the hollow electrode ( 5) Connect the high-temperature fluid inlet pipe (7) and the high-temperature fluid outlet pipe (8), and attach the high-voltage insulator (24) to the inner wall of the cylinder (22), and add the high-voltage insulator (24) to affect the flashover of the insulator Defect factor of voltage; Step 2. Set the temperatures of the high-temperature fluid tank (9) and the low-temperature fluid tank (19) respectively on the first low-temperature refrigeration device (10) and the second low-temperature refrigeration device (20). The ethylene glycol aqueous solution in the fluid box (9) and the low-temperature fluid box (19) is refrigerated, and the first temperature sensor (902) and the second temperature sensor (1902) are used to monitor the high-temperature fluid box (9) and the low-temperature fluid box respectively at the same time The temperature in (19), when the temperature is higher than the preset value, the first temperature sensor (902) and the second temperature sensor (1902) send a refrigeration signal, when the temperature reaches the preset value, the first temperature sensor (902) and the second temperature sensor (1902) respectively transmit temperature signals to the first low-temperature refrigeration equipment (10) and the second low-temperature refrigeration equipment (20), so that the high-temperature fluid box (9) and the low-temperature fluid box (19) stop cooling; Step 3, turn on the first water pump (901) and the second water pump (1901), continuously input the ethylene glycol aqueous solution into the hollow electrode (5), cool the high-voltage end and the low-voltage end of the high-voltage insulator (24), and wait for the high-voltage insulator After the electrode temperature of (24) is stable, adopt automatic step-up method to apply voltage to high voltage insulator (24) two ends, and monitor the voltage at high voltage insulator (24) two ends in real time with high voltage digital meter (31); Step 4. After the high-voltage insulator (24) flashes over, measure and record the flashover voltage, and immediately reduce the high-voltage power supply (29) to zero; Step 5, sequentially shut down the first low-temperature refrigeration equipment (10), the second low-temperature refrigeration equipment (20), the first water pump (901), and the second water pump (1901); Step 6, discharging the RC voltage divider (30); Step 7. After the temperature of the two ends of the high-voltage insulator (24) and the hollow electrode (5) returns to normal temperature, disassemble the closed air chamber (1), and observe the surface of the high-voltage insulator (24) at the defect due to flashover discharge. Traces and photographs are taken to confirm that flashover along the surface occurs at the defect; Step 8: Dispose of traces on the surface of the high-voltage insulator (24), then wipe it with absolute ethanol, and then repeat steps 1 to 7 for the next experiment. 4. the high-voltage insulator flashover test method along the surface under a kind of extremely cold condition according to claim 3, is characterized in that, described automatic step-up method is based on whether the high-voltage end and the low-voltage end of the high-voltage insulator (24) are required Temperature, if the temperature of the high-voltage end and the low-voltage end of the high-voltage insulator (24) is not the required temperature, the external transformer is adjusted to stop pressurizing the two ends of the high-voltage insulator (24), when the high-voltage end and the low-voltage end of the high-voltage insulator (24) are When the temperature is needed, adjust the external transformer to pressurize the high-voltage end and the low-voltage end of the high-voltage insulator (24), and judge whether the high-voltage insulator (24) has a flashover. ) of the high pressure end and the low pressure end temperature.