Insulation detection safety protection device for electrical maintenance of thermal power plant

Abstract

This invention discloses an insulation testing safety protection device for electrical maintenance in thermal power plants, belonging to the field of electrical maintenance safety protection technology in thermal power plants. The insulation testing safety protection device includes an insulating base, a testing mechanism, a protective cover, an alarm mechanism, a control panel, and a power module. The insulating base serves as the load-bearing structure of the entire device. The testing mechanism, mounted on the insulating base, is used to test the insulation resistance of the equipment under maintenance. The protective cover covers the outside of the testing mechanism, providing physical isolation and protection. The alarm mechanism is electrically connected to the testing mechanism and emits an audible and visual alarm signal when an insulation abnormality is detected. The control panel is located at the front of the insulating base for setting testing parameters and displaying test results. The power module provides operating power to the entire device. In use, the device is placed near the electrical equipment to be maintained. The testing mechanism performs insulation testing on the equipment. When the detected value is lower than a set threshold, the alarm mechanism automatically triggers an alarm. Simultaneously, the protective cover provides physical isolation to prevent accidental activation, thereby effectively protecting the personal safety of maintenance personnel and improving the safety and reliability of electrical maintenance operations. This invention has a compact structure and is easy to operate, making it particularly suitable for insulation testing and safety protection at the maintenance site of electrical equipment in thermal power plants.

Description

Technical Field

[0001] This invention relates to the field of electrical maintenance safety protection technology in thermal power plants, specifically to an insulation testing safety protection device for electrical maintenance in thermal power plants. Background Technology

[0002] A thermal power plant, also known as a coal-fired power plant, is a factory that uses combustible materials as fuel to produce electricity. Its basic working principle involves burning fuel in a boiler to convert chemical energy into heat energy, which heats water to generate high-temperature, high-pressure steam that drives a turbine. The turbine then drives a generator to convert mechanical energy into electrical energy. Thermal power plants bear the important responsibilities of base load control and peak-shaving / frequency regulation; their safe and stable operation is of great significance for ensuring the national economy and people's livelihoods.

[0003] During long-term operation, the insulation performance of electrical equipment in thermal power plants gradually deteriorates. When it drops below a critical value, insulation breakdown accidents are highly likely to occur, leading to safety incidents such as short circuits, electric arcs, and even fires and explosions, endangering the lives of maintenance personnel. Therefore, thermal power plants need to regularly conduct power outage maintenance and insulation resistance testing on electrical equipment.

[0004] Existing insulation testing devices have the following shortcomings: First, handheld testing requires maintenance personnel to hold the probe close to live equipment, posing a risk of electric shock, especially when testing high-voltage equipment where residual charge may not be fully released, causing serious electric shock injuries. Second, they lack effective physical isolation and protection structures, leaving operators directly exposed to danger zones in the event of accidental discharge or arcing. Third, their alarm functions are limited; in the noisy maintenance environment of a thermal power plant, a single digital display is unlikely to attract the attention of operators, easily leading to misjudgments and missed detections. Therefore, this paper proposes an insulation testing safety protection device for electrical maintenance in thermal power plants. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides an insulation testing safety protection device for electrical maintenance in thermal power plants, which solves the technical problems in the prior art, such as the risk of electric shock to operators who are too close to live equipment during testing, the lack of effective physical isolation and protection structures, and the single alarm function that is not easily noticed.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: an insulation testing safety protection device for electrical maintenance in thermal power plants, comprising: an insulation base (1), wherein the insulation base (1) is a rectangular flat plate structure integrally molded from epoxy resin insulation material, and the upper surface of the insulation base (1) is provided with mounting grooves and positioning holes for installing various components. A testing mechanism (2) is fixedly installed in the middle position of the upper surface of the insulation base (1), and the testing mechanism (2) includes an insulation testing probe (21), a reset spring (22), a guide sleeve (23), a connecting seat (24), and a signal transmission line (25). A protective cover (3) is provided on the outside of the testing mechanism (2), and the protective cover (3) includes a transparent cover (31), a hinge (32), a sealing strip (33), a latch (34), and a handle (35). An alarm mechanism (4) is fixedly installed on the right side of the upper surface of the insulation base (1), and the alarm mechanism (4) includes a buzzer (41), an indicator light (42), a controller (43), a voltage comparator (44), and a relay (45). The control panel (5) is embedded on the front surface of the insulating base (1). The control panel (5) is equipped with an LCD screen, function buttons and status indicator lights. The power module (6) is fixedly installed at the rear of the insulating base (1). The power module (6) includes a lithium battery pack and a charge / discharge management circuit.

[0007] When in use, first place the insulation testing safety protection device in the working area of ​​the electrical equipment to be repaired, and start the device by pressing the power switch button on the control panel (5). The power module (6) supplies power to each component. Open the protective cover (3), and align the insulation testing probe (21) of the testing mechanism (2) with the testing point of the equipment under test. The insulation testing probe (21) is in close contact with the surface under test under the action of the reset spring (22), and the detection signal is transmitted to the voltage comparator (44) through the signal transmission line (25). The voltage comparator (44) compares the detection signal with the set threshold. When the detected insulation resistance value is lower than the set threshold, the voltage comparator (44) outputs a high-level signal to trigger the relay (45) to close. After receiving the trigger signal, the controller (43) controls the buzzer (41) to emit a buzzer alarm sound, and at the same time the red LED indicator lights up. When the insulation test value is normal, the green LED indicator stays on. During the test, the transparent cover (31) is in the open state to facilitate probe contact with the object being tested. After the test is completed, the protective cover (3) is closed and locked by the latch (34). The transparent cover (31) provides physical isolation protection to prevent accidental contact with live parts. The entire device achieves reliable insulation isolation from the ground through the insulating base (1).

[0008] Preferred solution Preferably, the insulation detection probe (21) includes a probe body and a detection contact disposed at the front end of the probe body. The detection contact has a hemispherical structure, and its surface is coated with a conductive and wear-resistant layer. An annular limiting boss is disposed at the rear end of the probe body. A reset spring (22) is sleeved on the outside of the probe body. One end of the reset spring (22) abuts against the annular limiting boss, and the other end of the reset spring (22) abuts against the spring seat inside the guide sleeve (23). This structure enables the insulation detection probe (21) to automatically adjust the contact pressure with the surface being tested under the action of the reset spring (22), ensuring that the detection contact and the surface being tested always maintain good electrical contact, thereby improving the accuracy and reliability of the detection.

[0009] Preferably, the guide sleeve (23) is a cylindrical structure, and at least two guide grooves are provided on the inner wall of the guide sleeve (23) along the axial direction. A guide slider is correspondingly provided on the outer wall of the probe body. The guide slider slides in cooperation with the guide grooves. The lower end of the guide sleeve (23) is fixedly connected to the connecting seat (24) by threads. A buffer washer is provided in the connecting seat (24). The cooperation between the guide slider and the guide grooves makes the movement direction of the probe body precisely constrained, avoiding the probe from deflecting during the detection process. At the same time, the buffer washer in the connecting seat (24) can absorb the impact energy when the probe retracts, extending the service life of the device.

[0010] Preferably, the transparent cover (31) is injection molded from transparent polycarbonate engineering plastic, with a wall thickness of 3-5mm. The hinge (32) is a stainless steel hinge structure, with the two blades of the hinge (32) respectively fixed to the transparent cover (31) and the insulating base (1) by screws. The sealing strip (33) is made of silicone rubber, and the cross-section of the sealing strip (33) is an O-shaped structure. The transparent polycarbonate material has excellent light transmittance and impact resistance, making it easy for operators to observe the internal testing status. At the same time, it can withstand a certain degree of accidental impact. The stainless steel hinge ensures a service life of tens of thousands of opening and closing cycles for the protective cover. The silicone rubber sealing strip forms a reliable sealing environment when the protective cover is closed, preventing dust and moisture from entering the internal mechanism.

[0011] Preferably, the latch (34) includes a lock seat and a latch. The lock seat is fixedly installed on the front edge of the transparent cover (31), and the latch is rotatably installed on the lock seat via a pivot. A latch mating seat is fixedly provided on the front side of the insulating base (1) at a corresponding position. The latch engages and locks with the latch mating seat. The handle (35) has a U-shaped structure, and both ends of the handle (35) are rotatably installed on the top of the transparent cover (31) via a pivot. The latch structure is simple and reliable, and the opening and closing operation is convenient. The U-shaped handle conforms to the ergonomic design, making it convenient for operators to hold and carry the entire device.

[0012] Preferably, the buzzer (41) is a piezoelectric buzzer with an operating voltage of 3-12V. The indicator light (42) includes a red LED indicator and a green LED indicator. The red LED indicator lights up when the insulation detection value is lower than the set threshold, and the green LED indicator lights up when the insulation detection value is normal. The piezoelectric buzzer is characterized by its small size, low power consumption, and high sound pressure level. It can emit a clear alarm sound in the noisy maintenance environment of a thermal power plant. The red and green dual-color indicator lights have a clear color contrast, allowing operators to intuitively and quickly judge the insulation status of the equipment.

[0013] Preferably, the controller (43) is a microcontroller chip based on the ARM Cortex-M0 core, the voltage comparator (44) is an LM393 dual voltage comparator chip, the reference voltage of the voltage comparator (44) is provided by the power supply module (6) through a voltage divider resistor network, the relay (45) is a solid-state relay, the coil terminal of the relay (45) is electrically connected to the output terminal of the voltage comparator (44), and the contact terminal of the relay (45) is connected in series between the power supply module (6) and the buzzer (41). The ARM Cortex-M0 microcontroller has the characteristics of low power consumption and high integration, and can realize accurate detection and control logic. The solid-state relay has fast response speed, no contact noise, and long life, ensuring the high reliability of the alarm circuit.

[0014] Preferably, the LCD screen on the control panel (5) is a 128×64 dot matrix LCD screen, and the function buttons include a power switch button, a detection start button, a threshold setting button, and a reset button. The control panel (5) is equipped with a data storage chip for storing detection data and setting parameters. The dot matrix LCD screen can clearly display detection values, units, status information, and battery power, etc. The data storage chip allows the detection data to be stored for a long time, which is convenient for subsequent analysis and traceability.

[0015] Preferably, the lithium battery pack of the power module (6) consists of four 18650 lithium-ion batteries connected in series. The charge and discharge management circuit uses a TP4056 charge and discharge management chip. The output terminal of the power module (6) is equipped with an overcurrent protection circuit and an overvoltage protection circuit. The side of the power module (6) is equipped with a USB charging interface and a power indicator bar. The 18650 lithium battery pack has the advantages of large capacity and long cycle life, which can meet the power demand of continuous detection work for several hours. The charge and discharge management circuit ensures the charging safety of the battery and extends the battery life. The overcurrent protection and overvoltage protection circuits provide reliable power safety for the entire device.

[0016] Preferably, the insulating base (1) has anti-slip rubber pads at the four corners of its lower surface, and a heat dissipation grid is provided on the side of the insulating base (1). The epoxy resin insulating material of the insulating base (1) has an insulation resistance of not less than 1000MΩ and a dielectric strength of not less than 20kV / mm. The anti-slip rubber pads provide reliable friction on smooth surfaces, preventing the device from sliding during use. The heat dissipation grid facilitates the heat dissipation of internal circuit components, ensuring the thermal stability of the device during long-term operation. The epoxy resin material with high insulation resistance and high dielectric strength ensures the safety of the device in high-voltage electrical equipment testing scenarios.

[0017] (III) Beneficial Effects Compared with the prior art, the present invention provides an insulation testing safety protection device for electrical maintenance of thermal power plants, which has the following beneficial effects: The insulation testing safety protection device for electrical maintenance of thermal power plants, through the physical isolation structure with a protective cover (3), allows the transparent cover (31) to be closed and locked after the test is completed, effectively isolating the operator from the test area. Even if an accidental discharge or arc occurs, the transparent cover (31) can provide a reliable protective barrier, avoiding the operator being directly exposed to the dangerous area. At the same time, the transparent polycarbonate material makes it easy for the operator to observe the internal condition without opening the protective cover, which greatly improves the safety of maintenance operations. With the addition of an automatic detection and alarm linkage structure consisting of an insulation detection probe (21), a reset spring (22), a guide sleeve (23), and a voltage comparator (44), the insulation detection probe (21) automatically maintains good contact with the surface being tested under the action of the reset spring (22). The voltage comparator (44) compares the detection signal with the set threshold in real time. Once the detection value is abnormal, the buzzer (41) and indicator light (42) are triggered by the relay (45) to issue an audible and visual alarm. The dual alarm mode ensures that the operator can detect the alarm in a timely manner even in a noisy maintenance site. With the addition of an insulating base (1) made of epoxy resin insulating material and a power module (6) with a charge and discharge management circuit, the insulating base (1) provides high insulation resistance and high dielectric strength insulation isolation, enabling the entire device to work safely and reliably at the high-voltage electrical equipment maintenance site. The overcurrent protection and overvoltage protection circuits of the power module (6) provide multi-level power safety protection for the device, thereby greatly improving the safety and detection efficiency of electrical maintenance operations in thermal power plants. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of an insulation testing and safety protection device for electrical maintenance in thermal power plants according to the present invention. Figure 2 This is a cross-sectional structural diagram of the detection mechanism of the present invention; Figure 3 This is a partial structural schematic diagram of the protective cover of the present invention; Figure 4 This is a cross-sectional structural diagram of the alarm mechanism of the present invention.

[0019] In the diagram: 1. Insulating base; 2. Detection mechanism; 21. Insulation detection probe; 22. Return spring; 23. Guide sleeve; 24. Connecting seat; 25. Signal transmission line; 3. Protective cover; 31. Transparent cover; 32. Hinge; 33. Sealing strip; 34. Lock; 35. Handle; 4. Alarm mechanism; 41. Buzzer; 42. Indicator light; 43. Controller; 44. Voltage comparator; 45. Relay; 5. Control panel; 6. Power module. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figure 1 An insulation testing safety protection device for electrical maintenance in thermal power plants includes an insulating base (1). The insulating base (1) serves as the load-bearing base of the entire device and is made of epoxy resin insulating material through a molding process. Its dimensions are 350mm in length, 240mm in width, and 35mm in height. The upper surface of the insulating base (1) has multiple mounting slots and positioning holes for mounting the testing mechanism (2), the alarm mechanism (4), and the power module (6), respectively. The front end is fitted with a control panel (5), and the four corners of the lower surface are fitted with anti-slip rubber pads. Heat dissipation grilles are provided on both sides. The testing mechanism (2) is fixed to the middle of the upper surface of the base with screws. A protective cover (3) covers the outside of the testing mechanism (2). One side of the cover is connected to the insulating base (1) through a hinge (32), and the other side is locked with a buckle (34). The alarm mechanism (4) is fixed to the right side of the upper surface of the insulating base (1). The control panel (5) is embedded in the groove on the front end of the insulating base (1). The power module (6) is fixed to the rear of the upper surface of the insulating base (1) and is covered with a metal shield. The connecting wires between the electrical components are all made of flame-retardant polyvinyl chloride insulated wires and are routed through the wire grooves inside the base.

[0022] Please see Figure 2The testing mechanism (2) is the core component for insulation resistance testing, mainly including the insulation testing probe (21), the reset spring (22), the guide sleeve (23), the connecting seat (24), and the signal transmission line (25). The insulation testing probe (21) consists of a probe body and a testing contact. The probe body is machined from stainless steel bar with a diameter of 10mm and a length of 120mm. The testing contact is a hemispherical structure with a spherical radius of 8mm and a nickel-based alloy conductive wear-resistant layer plated on the surface. An annular limiting boss is provided at the rear end of the probe body to limit the installation position of the reset spring (22). The reset spring (22) is a cylindrical helical compression spring, made of 65Mn spring steel wire with a wire diameter of 1.2mm, an outer diameter of 12mm, and a free length of 60mm, which can provide an initial elastic force of about 8N. The guide sleeve (23) is a cylindrical nylon 66 injection molded part with a length of 100mm and three trapezoidal guide grooves evenly opened along the circumference of the inner wall. Three guide sliders are provided on the outer wall of the probe body. The guide sliders and guide grooves form a sliding fit with a gap of 0.1-0.2mm, which ensures free sliding and effectively restricts radial movement. The connector (24) is made of brass and has a nitrile rubber buffer washer installed in the central blind hole to absorb the impact energy when the probe retracts. The signal transmission line (25) is a double-shielded coaxial cable with a silver-plated copper wire inner conductor and a polytetrafluoroethylene insulation layer. One end is electrically connected to the probe body and the other end is connected to the input of the voltage comparator (44).

[0023] Please see Figure 3 The protective cover (3) is an important safety protection structure of the present invention, mainly including a transparent cover (31), a hinge (32), a sealing strip (33), a latch (34), and a handle (35). The transparent cover (31) is made of polycarbonate transparent engineering plastic injection molding, with a dome-shaped structure, a maximum length of 200mm, a width of 160mm, a height of 110mm, a wall thickness of 4mm, and a light transmittance of over 90%. The hinge (32) is a 304 stainless steel hinge structure, with two blades fixed to the rear side of the transparent cover (31) and the rear side of the insulating base (1) respectively by self-tapping screws, and a self-lubricating nylon bushing is provided at the pivot. The sealing strip (33) is made of silicone rubber extrusion molding, with an O-shaped cross section, and is set circumferentially along the lower edge of the transparent cover, forming a reliable seal when closed. The latch (34) consists of a nylon 66 lock seat and a 45# steel galvanized lock tongue, which rotates and engages in the slot of the latch mating seat to achieve locking. The handle (35) is made of ABS engineering plastic injection molding and has a U-shaped structure. Both ends are installed on the top of the transparent cover through the rotating shaft, with a rotation angle of 0°-90°.

[0024] Please see Figure 4The alarm mechanism (4) is the core control component for realizing audible and visual alarms in abnormal states. It mainly includes a buzzer (41), indicator lights (42), a controller (43), a voltage comparator (44), and a relay (45). The overall housing is made of die-cast aluminum alloy, with dimensions of 80mm in length, 60mm in width, and 40mm in height. The buzzer (41) is a piezoelectric buzzer, model HYDZ-3210, with a working voltage of 3-12V and a sound pressure level of 85-105dB. The indicator lights (42) include one red (wavelength 625nm) and one green (wavelength 525nm) 5mm high-brightness through-hole LED. The controller (43) is an ARM Cortex-M0 core microcontroller STM32F030F4P6 with 16KB Flash and 4KB SRAM, and a working frequency of 48MHz. The voltage comparator (44) is an LM393 dual voltage comparator chip. The non-inverting input receives the detection signal, and the inverting input obtains the reference voltage through a voltage divider resistor network. The reference voltage value can be adjusted by the operator through the control panel (5). The relay (45) is a solid-state relay AQY212EH. Its input is connected to the output of the voltage comparator (44) through a current-limiting resistor, and its output is connected in series between the power supply module (6) and the buzzer (41). When the detection signal is lower than the reference voltage, the voltage comparator (44) outputs a high level to drive the relay to conduct, the buzzer (41) is powered on and alarms, the red LED lights up, and the green LED turns off, forming a dual alarm of sound and light. When the detection signal recovers, the system automatically resets.

[0025] The working process of this invention is as follows: First, place the device on a flat surface near the electrical equipment to be repaired, start the device through the control panel (5), and the power module (6) starts supplying power. The operator sets the insulation resistance alarm threshold through the threshold setting button. Then, open the protective cover (3), press the detection start button, and the insulation detection probe (21) extends under the elastic force of the reset spring (22), pressing the detection contact onto the insulation surface of the electrical equipment under test. The detection signal is transmitted to the voltage comparator (44) for analysis and comparison through the signal transmission line (25). If the insulation resistance value is normal, the green LED indicator light is always on; if it is lower than the threshold, the voltage comparator (44) triggers the relay (45) to conduct, the buzzer (41) sounds an alarm, and the red LED indicator light flashes. After the test is completed, the insulation detection probe (21) automatically retracts into the guide sleeve (23), the protective cover (3) is closed and locked, and the transparent cover (31) provides physical isolation protection. All test data is automatically stored in the data storage chip and can be viewed through the history function of the LCD screen. Through the close coordination of the above structure and working process, this device achieves a comprehensive safety protection function that integrates insulation detection, audible and visual alarms, and physical isolation protection.

[0026] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0027] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A safety protection device for insulation testing during electrical maintenance in thermal power plants, characterized in that, include: An insulating base (1) is a rectangular flat plate structure integrally molded from epoxy resin insulating material. The upper surface of the insulating base (1) is provided with mounting grooves and positioning holes for installing various components. A detection mechanism (2) is fixedly installed in the middle of the upper surface of the insulating base (1). The detection mechanism (2) includes an insulation detection probe (21), a reset spring (22), a guide sleeve (23), a connecting seat (24), and a signal transmission line (25). The insulation detection probe (21) is slidably mounted on the guide sleeve (23) through the reset spring (22). Inside, the connecting seat (24) is fixedly installed at the bottom of the guide sleeve (23), and one end of the signal transmission line (25) is electrically connected to the insulation detection probe (21); the protective cover (3) is installed on the outside of the detection mechanism (2), and the protective cover (3) includes a transparent cover (31), a hinge (32), a sealing strip (33), a latch (34) and a handle (35). The transparent cover (31) is installed on the insulating base (1) in an openable and closable manner through the hinge (32). The sealing strip (33) is arranged circumferentially along the lower edge of the transparent cover (31), and the latch (34) is installed on the transparent cover. The front side of the transparent cover (31) is locked to the insulating base (1), and the handle (35) is fixedly set on the top of the transparent cover (31); the alarm mechanism (4) is fixedly installed on the right side of the upper surface of the insulating base (1). The alarm mechanism (4) includes a buzzer (41), an indicator light (42), a controller (43), a voltage comparator (44), and a relay (45). The buzzer (41) and the indicator light (42) are electrically connected to the controller (43), and the input terminal of the voltage comparator (44) is electrically connected to the signal transmission line (25) of the detection mechanism (2). The output of the voltage comparator (44) is electrically connected to the controller (43) via a relay (45); the control panel (5) is embedded on the front surface of the insulating base (1), and the control panel (5) is equipped with an LCD screen, function buttons and status indicator lights; the power module (6) is fixedly installed at the rear of the insulating base (1), and the power module (6) includes a lithium battery pack and a charge and discharge management circuit, and the output of the power module (6) is electrically connected to the detection mechanism (2), the alarm mechanism (4) and the control panel (5) respectively.

2. The insulation testing and safety protection device for electrical maintenance in thermal power plants according to claim 1, characterized in that: The insulation detection probe (21) includes a probe body and a detection contact located at the front end of the probe body. The detection contact has a hemispherical structure and a conductive wear-resistant layer is plated on its surface. An annular limiting boss is provided at the rear end of the probe body. A reset spring (22) is sleeved on the outside of the probe body. One end of the reset spring (22) abuts against the annular limiting boss, and the other end of the reset spring (22) abuts against the spring seat inside the guide sleeve (23).

3. The insulation testing and safety protection device for electrical maintenance in thermal power plants according to claim 1, characterized in that: The guide sleeve (23) is a cylindrical structure. The inner wall of the guide sleeve (23) is provided with at least two guide grooves along the axial direction. The outer wall of the probe body is provided with a guide slider. The guide slider slides in cooperation with the guide groove. The lower end of the guide sleeve (23) is fixedly connected to the connecting seat (24) by a thread. A buffer washer is provided inside the connecting seat (24).

4. The insulation testing and safety protection device for electrical maintenance in thermal power plants according to claim 1, characterized in that: The transparent cover (31) is injection molded from polycarbonate transparent engineering plastic. The wall thickness of the transparent cover (31) is 3-5mm. The hinge (32) is a stainless steel hinge structure. The two blades of the hinge (32) are respectively fixed on the transparent cover (31) and the insulating base (1) by screws. The sealing strip (33) is made of silicone rubber and has an O-shaped cross section.

5. The insulation testing and safety protection device for electrical maintenance in thermal power plants according to claim 1, characterized in that: The latch (34) includes a lock seat and a latch. The lock seat is fixedly installed on the front edge of the transparent cover (31). The latch is rotatably installed on the lock seat through a pivot. A latch mating seat is fixedly provided on the front side of the insulating base (1). The latch engages and locks with the latch mating seat. The handle (35) is a U-shaped structure. Both ends of the handle (35) are rotatably installed on the top of the transparent cover (31) through a pivot.

6. The insulation testing and safety protection device for electrical maintenance in thermal power plants according to claim 1, characterized in that: The buzzer (41) is a piezoelectric buzzer with a working voltage of 3-12V. The indicator light (42) includes a red LED indicator and a green LED indicator. The red LED indicator lights up when the insulation detection value is lower than the set threshold, and the green LED indicator lights up when the insulation detection value is normal.

7. The insulation testing and safety protection device for electrical maintenance in thermal power plants according to claim 1, characterized in that: The controller (43) is a microcontroller chip based on the ARM Cortex-M0 core, the voltage comparator (44) is an LM393 dual voltage comparator chip, the reference voltage of the voltage comparator (44) is provided by the power supply module (6) through a voltage divider resistor network, the relay (45) is a solid-state relay, the coil end of the relay (45) is electrically connected to the output end of the voltage comparator (44), and the contact end of the relay (45) is connected in series between the power supply module (6) and the buzzer (41).

8. The insulation testing and safety protection device for electrical maintenance in thermal power plants according to claim 1, characterized in that: The LCD screen on the control panel (5) is a 128×64 dot matrix LCD screen. The function buttons include a power switch button, a detection start button, a threshold setting button, and a reset button. The control panel (5) is equipped with a data storage chip to store detection data and setting parameters.

9. The insulation testing and safety protection device for electrical maintenance in thermal power plants according to claim 1, characterized in that: The lithium battery pack of the power module (6) consists of four 18650 lithium-ion batteries connected in series. The charge and discharge management circuit uses a TP4056 charge and discharge management chip. The output terminal of the power module (6) is equipped with an overcurrent protection circuit and an overvoltage protection circuit. The side of the power module (6) is equipped with a USB charging interface and a power indicator bar.

10. The insulation testing and safety protection device for electrical maintenance in thermal power plants according to claim 1, characterized in that: Anti-slip rubber pads are provided at the four corners of the lower surface of the insulating base (1). A heat dissipation grid is provided on the side of the insulating base (1). The insulation resistance of the epoxy resin insulating material of the insulating base (1) is not less than 1000MΩ and the dielectric strength is not less than 20kV / mm.

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