Temperature-adjustable basin-type insulator scale model experiment device

Abstract

A temperature-adjustable basin-type insulator scale model experiment device belongs to the technical field of power equipment and comprises a high-pressure experiment tank body, a temperature adjusting device, a temperature monitoring unit, a temperature feedback control unit and a multi-signal detection unit. A plurality of sensors are combined to synchronously detect discharge signals, discharge characteristics of different signals are obtained, the influence of the temperature on the electrical performance of the basin-type insulator can be explored, meanwhile, research on the insulation failure mechanism of power equipment in a low-temperature environment is facilitated, and the simulation detection integrated device is convenient and reliable.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power equipment, and in particular relates to a temperature-adjustable pot-type insulator scaled model experimental device. Background Art

[0002] Basin insulators are widely used in GIS equipment, and their performance directly affects the reliability of GIS operation. GIS is one of the important components of the power system, and SF6 gas is often used as the insulating medium. Its safe and stable operation is of great significance to the reliability of the power system.

[0003] The interface between the center conductor of the pot insulator and the epoxy insulation is the most complex part of the pot insulator. The stress concentration phenomenon is obvious, especially the thermal stress during operation, which can easily cause mechanical damage to the pot insulator, resulting in interface defects and insulation failure, threatening the safe and reliable operation of GIS equipment. The pot insulator works in SF6 gas for a long time. Its overheating failure will cause local temperature rise, which may cause thermal breakdown, affect its insulation strength and cause accidents. In recent years, the lowest winter temperature in northern my country has frequently hit new lows, which may cause the insulating gas to liquefy and the overall insulation capacity to decrease, which has brought severe challenges to the normal operation of GIS. The greenhouse effect potential (GWP) of SF6 gas is 23900 times that of CO2. It is listed as one of the restricted greenhouse gases in the Kyoto Protocol. Since the discharge characteristics and insulation failure mechanisms of these replacement gases are quite different from those of SF6 gas, the research on SF6 environmentally friendly replacement gases has gradually increased. Zhou Wenjun and others from Wuhan University studied the effect of temperature on the insulation strength of C4F7N / CO2 mixed gas. The results show that when the temperature is lower than the liquefaction temperature of the mixed gas, the insulation strength will be significantly reduced. However, there are relatively few studies on the perception and operation of the insulation state of pot-type insulators under different temperature conditions, and there are certain limitations. Most of the studies are limited to simulation analysis of the impact of temperature on its insulation state, and cannot fully explore the impact of various temperature conditions on the operation of pot-type insulators.

[0004] Therefore, the prior art urgently needs a new technical solution to solve the above problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a temperature-adjustable pot-type insulator scale model experimental device, which can simulate the local discharge of pot-type insulators under different temperature conditions from actual experiments, study the influence of temperature on the electrical properties of pot-type insulators, and lay the foundation for the study of low-temperature insulation failure of environmentally friendly replacement gas-insulated pot-type insulators, which is of great significance to the safe and stable operation of the power system.

[0006] A temperature-adjustable pot-type insulator scale model experimental device comprises a high-voltage experimental tank, a temperature regulating device, a temperature monitoring unit, a temperature feedback control unit and a multi-signal detection unit;

[0007] The high-voltage test tank is provided with an insulating sleeve inside and a semicircular ring in the middle of the outer side, which divides the high-voltage test tank into two parts, each of which is provided with a valve and an optical window; one end of the high-voltage test tank is connected to the high-voltage guide rod, and the other end is grounded;

[0008] The temperature regulating device is provided with a sealed vacuum container outside, and a vacuum valve is provided on the vacuum container; the temperature regulating head of the temperature regulating device is connected with the semicircular ring, and is used for heating or cooling the high-pressure experimental tank;

[0009] The temperature monitoring unit is arranged inside the high-voltage test tank, and includes a temperature sensor and an infrared camera, and is used to detect the internal ambient temperature of the tank and the temperature gradient of the pot-type insulator;

[0010] The temperature feedback control unit is connected to the temperature monitoring unit signal and is used to control the output power of the cold source or the heat source;

[0011] The multi-signal detection unit includes an ultra-high frequency (UHF), a pulse current, an optical signal sensor and a multi-channel acquisition card. The optical signal sensor is fixedly arranged at two optical windows of the high-voltage experimental tank body to detect partial discharge optical signals of various bands inside the tank body.

[0012] The semicircular ring is connected to the high pressure test tank through screws and nuts.

[0013] The temperature regulating device adopts a refrigerator for refrigeration, and the refrigeration process is as follows: the temperature regulating head of the refrigerator cools down the semicircular ring, and the semicircular ring cools down the pot-type insulator inside the high-voltage test tank through metal conduction;

[0014] The temperature regulating device adopts a heating resistor for heating, and the heating process is as follows: the resistance heating element heats the semicircular ring, and the semicircular ring heats the pot-type insulator inside the high-voltage test tank through metal conduction.

[0015] The infrared camera monitors the temperature distribution on the surface of the basin insulator. The temperature of a point on the basin insulator is:

[0016] T=a·I+b

[0017] Where T is the actual temperature; I is the pixel intensity in the infrared image; a and b are calibration parameters, which are obtained by linear regression fitting of the actual temperature measured by the standard thermocouple and the infrared image pixels under different temperature conditions; the radial temperature gradient distribution on the surface of the basin insulator is obtained, assuming that the temperature distribution on the same plane of the insulator is the same, and the formula is:

[0018]

[0019] In the formula, is the radial temperature gradient of the insulator, and Δx is the pixel spacing of the infrared image.

[0020] The temperature feedback control unit adopts a PID closed-loop control method, specifically: calculating the local temperature gradient G of the pot-type insulator at each key point or area inside the high-voltage test tank (1), comparing each local temperature gradient G with the corresponding maximum temperature gradient G max Compare and then add up the ΔP values ​​to get the average value.

[0021]

[0022] Where P is the target power; ΔP is the power change value obtained by a single local calculation; is the overall power change value of the cold source or heat source; G is the temperature gradient; G max is the maximum allowable temperature gradient; k is the adjustment coefficient;

[0023] When the maximum temperature gradient monitored exceeds G max When the temperature gradient is lower than G max When the power output is increased, the cooling or heating process of the cold source or heat source is accelerated.

[0024] Through the above-mentioned design scheme, the present invention can bring the following beneficial effects: a temperature-adjustable pot-type insulator scale model experimental device, which combines multiple sensors to synchronously detect discharge signals and obtain discharge characteristics of different signals, can explore the influence of temperature on the electrical properties of pot-type insulators, and at the same time contribute to the study of the mechanism of insulation failure of power equipment in low-temperature environments. It is a convenient and reliable integrated simulation detection device.

[0025] Furthermore, the present invention adopts a PID closed-loop control method to realize the function of automatic feedback adjustment of temperature; by adopting an infrared camera, the change process of the temperature gradient on the surface of the basin-type insulator is timely reflected; by using multiple sensors to synchronously collect partial discharge signals, the discharge characteristics of multiple signals can be obtained, and the development process of the partial discharge signal of the basin-type insulator under different temperature conditions can be studied more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is further described below with reference to the accompanying drawings and specific embodiments:

[0027] Figure 1 The present invention is a schematic structural diagram of a temperature-adjustable pot-type insulator scaled model experimental device.

[0028] Figure 2 The present invention is a schematic diagram of a semicircular ring structure of a scaled model experimental device of a temperature-adjustable pot-type insulator.

[0029] Figure 3 The present invention is a temperature feedback control principle diagram of a temperature-adjustable pot-type insulator scaled model experimental device.

[0030] In the figure, 1-high-voltage test tank, 101-insulating sleeve, 102-semicircular ring, 103-high-voltage guide rod, 104-valve, 105-optical window, 2-temperature regulating device. DETAILED DESCRIPTION

[0031] A temperature-adjustable pot-type insulator scale model experimental device, such as Figure 1 As shown, it includes a high-pressure experimental tank 1 and a temperature regulating device 2, and the control part includes a temperature monitoring unit, a temperature feedback control unit and a multi-signal detection unit.

[0032] A semicircular ring 102 is arranged in the middle of the outer side of the high-voltage test tank 1, dividing the high-voltage test tank 1 into two parts, each part is provided with a valve 104 and an optical window 105; one end of the high-voltage test tank 1 is connected to the high-voltage guide rod 103, and the other end is grounded; an insulating sleeve 101 is arranged in the middle for insulation to prevent breakdown; a basin-type insulator is located in the middle position, and the maximum normal working pressure is 6 atmospheres, and a light guide is placed at the bottom of the upper and lower parts for collecting optical signals.

[0033] The temperature regulating device 2 is located at the semicircular ring 102 of the high-voltage test tank 1, and the pot-type insulator is cooled or heated through the semicircular ring 102. There is a vacuum container outside the device to reduce power and temperature losses.

[0034] The temperature regulating device 2 adopts a refrigerator for cooling, and the cooling process is as follows: the temperature regulating head of the refrigerator cools down the semicircular ring 102, and the semicircular ring 102 cools down the pot-type insulator inside the high-voltage test tank body 1 through metal conduction; a heating resistor is adopted for heating, and the heating process is as follows: the resistance heating element heats the semicircular ring 102, and the semicircular ring 102 heats the pot-type insulator inside the high-voltage test tank body 1 through metal conduction.

[0035] The temperature monitoring unit includes a temperature sensor and an infrared camera. The temperature sensor can detect the ambient temperature, and the infrared camera can reflect the temperature of the pot insulator through images, which can be further processed to obtain the radial temperature gradient of the insulator.

[0036] The temperature feedback control unit is a PID closed-loop control system.

[0037] The temperature feedback control unit calculates the local temperature gradient G of the pot-type insulator at each key point or area inside the high-voltage test tank 1, and compares each local temperature gradient G with the corresponding maximum temperature gradient G max Compare and then add up the ΔP values ​​to get the average value.

[0038]

[0039] Where P is the target power; ΔP is the power change value obtained by a single local calculation; is the overall power change value of the cold source or heat source; G is the temperature gradient; G max is the maximum allowable temperature gradient; k is the adjustment coefficient;

[0040] When the maximum temperature gradient monitored exceeds G max When the temperature gradient is lower than G max When the power output is increased, the cooling or heating process of the cold source or heat source is accelerated.

[0041] Specifically, Figure 3 As shown in the figure, it is the temperature feedback control principle diagram. The deviation value between the set temperature and the temperature sensor is input into the comparator to determine whether the error exceeds 0.1°C. If the deviation exceeds 0.1°C, the output power of the temperature regulating device is jointly determined according to the working mode and the difference between the absolute value of the temperature gradient and the maximum temperature gradient.

[0042] When the maximum temperature gradient monitored exceeds Gmax, the power output will be reduced accordingly to slow down the cooling or heating process of the cold source or heat source; conversely, if the temperature gradient is lower than Gmax, the power output will increase to speed up the cooling or heating process of the cold source or heat source until the difference between the set temperature and the actual temperature is less than 0.1°C. If it is less than 0.1°C and the temperature gradient difference is less than 0.001, the output power will be kept stable.

[0043] If it is in cooling mode, the absolute value of the temperature gradient G is lower than Gmax, the output power of the cold source increases; if the absolute value of the temperature gradient G is higher than Gmax, the output power of the cold source decreases. If it is in heating mode, the absolute value of the temperature gradient G is lower than Gmax, the output power of the heat source increases; if the absolute value of the temperature gradient G is higher than Gmax, the output power of the heat source decreases.

[0044] First, input the deviation between the set temperature and the temperature sensor into the comparator to determine whether the error exceeds 0.1°C. If it exceeds 0.1°C,

[0045] The multi-signal detection part is composed of UHF, pulse current and single-photon optical signal sensors and multi-channel acquisition cards. The optical signal sensor is an array based on SiPM (silicon photomultiplier tube), which is fixed at the windows of the upper and lower parts of the high-voltage tank. The ultraviolet band, infrared band and other optical signals inside the tank can be well transmitted through the fused quartz glass to detect local discharge optical signals in different bands. At the same time, the internal situation of the tank can be observed through the fused quartz glass at the bottom. The UHF sensor is placed inside the high-voltage experimental tank, and the multi-channel acquisition card synchronously collects the signals output by the sensor.

[0046] The application of the temperature-adjustable pot-type insulator scale model experimental device of the present invention is as follows:

[0047] A high-voltage experimental tank 1 that works normally under 220kV AC voltage and 6 atmospheres of internal pressure, a temperature regulating device that can heat or cool the pot-type insulator, a temperature monitoring unit that can observe the temperature gradient distribution of the pot-type insulator, a temperature feedback control unit that regulates the surface temperature of the pot-type insulator, and a multi-signal detection part that synchronously collects multiple photoelectric signals.

[0048] After the device is turned on, the working mode (cooling / heating) of the temperature control device is set, the actual temperature measured by the temperature sensor is compared with the set temperature, and the temperature feedback control unit is input to control the working state of the temperature control device. After the error between the actual temperature of the insulator and the set temperature is stabilized to less than 0.1°C, a high-voltage power supply is applied. The working voltage of the basin insulator is provided by the external power supply of the high-voltage bushing. The partial discharge experiment is carried out according to the experimental requirements, and the discharge signals of various sensors are synchronously collected by the multi-channel acquisition card for recording.

Claims

1. A temperature-adjustable pot-type insulator scale model experimental device, characterized by: It comprises a high-pressure experimental tank (1), a temperature regulating device (2), a temperature monitoring unit, a temperature feedback control unit and a multi-signal detection unit; The high-voltage test tank (1) is provided with an insulating sleeve (101) inside and a semicircular ring (102) in the middle of the outer side, dividing the high-voltage test tank (1) into two parts, each part being provided with a valve (104) and an optical window (105); one end of the high-voltage test tank (1) is connected to a high-voltage guide rod (103), and the other end is grounded; The temperature regulating device (2) is provided with a sealed vacuum container outside, and a vacuum valve is provided on the vacuum container; the temperature regulating head of the temperature regulating device (2) is connected to the semicircular ring (102) and is used for heating or cooling the high-pressure experimental tank (1); The temperature monitoring unit is arranged inside the high-voltage test tank (1), and comprises a temperature sensor and an infrared camera, and is used to detect the internal ambient temperature of the tank and the temperature gradient of the pot-type insulator; The temperature feedback control unit is connected to the temperature monitoring unit signal and is used to control the output power of the cold source or the heat source; The multi-signal detection unit comprises an ultra-high frequency (UHF), a pulse current, an optical signal sensor and a multi-channel acquisition card. The optical signal sensor is fixedly arranged at two optical windows of a high-voltage experimental tank (1) and is used to detect partial discharge optical signals of various bands inside the tank.

2. The temperature-adjustable pot-type insulator scale model experimental device according to claim 1 is characterized in that: The semicircular ring (102) is connected to the high-pressure test tank (1) via screws and nuts.

3. The temperature-adjustable pot-type insulator scale model experimental device according to claim 1 is characterized in that: The temperature regulating device (2) uses a refrigerator for refrigeration, and the refrigeration process is as follows: the temperature regulating head of the refrigerator cools the semicircular ring (102), and the semicircular ring (102) cools the pot-type insulator inside the high-voltage test tank (1) through metal conduction; The temperature regulating device (2) uses a heating resistor for heating, and the heating process is as follows: the resistance heating element heats the semicircular ring (102), and the semicircular ring (102) heats the pot-type insulator inside the high-voltage test tank (1) through metal conduction.

4. The temperature-adjustable pot-type insulator scale model experimental device according to claim 1 is characterized in that: The infrared camera monitors the temperature distribution on the surface of the basin insulator. The temperature of a point on the basin insulator is: T=a·I+b Where T is the actual temperature; I is the pixel intensity in the infrared image; a and b are calibration parameters, which are obtained by linear regression fitting of the actual temperature measured by the standard thermocouple and the infrared image pixels under different temperature conditions; the radial temperature gradient distribution on the surface of the basin insulator is obtained, assuming that the temperature distribution on the same plane of the insulator is the same, and the formula is: In the formula, is the radial temperature gradient of the insulator, and Δx is the pixel spacing of the infrared image.

5. The temperature-adjustable pot-type insulator scale model experimental device according to claim 1 is characterized in that: The temperature feedback control unit calculates the local temperature gradient G of the pot-type insulator at each key point or area inside the high-voltage test tank (1), and compares each local temperature gradient G with the corresponding maximum temperature gradient G. max Compare and then add up the ΔP values ​​to get the average value. Where, P is the target power; ΔP is the power change value obtained by a single local calculation; is the overall power change value of the cold source or heat source; G is the temperature gradient; G max is the maximum allowable temperature gradient; k is the adjustment coefficient; When the maximum temperature gradient monitored exceeds G max When the temperature gradient is lower than G max When the power output is increased, the cooling or heating process of the cold source or heat source is accelerated.

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