Cable insulation test circuit and test method thereof

Abstract

The invention provides a cable insulation test circuit and a test method thereof, and the circuit comprises a main control module, a line state inspection module, an insulation test module, a discharge module, a signal indication module, a touch screen module and a line control module, the output end of the main control module is respectively connected with the line state inspection module, the insulation test module, the discharge module, the signal indication module, the touch screen module and the line control module; the main control module is used for sending control instructions to the line state inspection module, the insulation test module, the discharge module, the signal indication module, the touch screen module and the line control module; receiving test data and state information of the line state inspection module, the insulation test module, the discharge module, the signal indication module, the touch screen module and the line control module, and processing the data; and a line state checking module.

Description

Technical Field

[0001] The invention belongs to the technical field of cable insulation testing, and in particular relates to a cable insulation testing circuit and a testing method thereof. Background Art

[0002] After the aircraft cables have completed the scheduled installation and wiring, they must be tested for electrical properties in accordance with relevant standards (HB6438-2005 "General Requirements for Aircraft Wiring Harness Processing" and technical requirements, among which insulation testing is an indispensable part.

[0003] The insulation resistance test mainly refers to the quantitative detection of the insulation performance between the corresponding wire cable and the helicopter shell. The insulation reliability is judged based on the test results. The principle is to apply a 500V DC high voltage between the corresponding wire cable and the helicopter shell to measure the resistance formed by the leakage current due to imperfect insulation. Insulation resistance is a limiting factor in designing high impedance. Reduced insulation resistance means increased leakage current, forming a feedback loop, which will destroy the normal operation of the circuit. The heat or DC current generated by excessive leakage current will cause insulation damage or deterioration of electrical performance. Therefore, insulation resistance is an important indicator for judging its insulation performance.

[0004] However, when measuring the insulation resistance of aircraft cables, the applied DC voltage is usually high, and existing measuring equipment lacks protection measures and alarm circuits. When the operation is not standardized or the measured line is not well insulated, the continuous high-voltage output of the insulation megohmmeter poses the risk of damaging electronic components in the line or causing casualties. Summary of the invention

[0005] The present application provides a cable insulation test circuit, which is used to solve the problem that existing measuring equipment lacks protection measures and alarm circuits.

[0006] In a first aspect, the present application provides a cable insulation test circuit, including a main control module, a line status check module, an insulation test module, a discharge module, a signal indication module, a touch screen module, and a line control module, wherein:

[0007] The input end of the main control module is connected to the touch screen module, and the output end of the main control module is respectively connected to the line status inspection module, the insulation test module, the discharge module, the signal indication module, the touch screen module and the line control module;

[0008] The main control module is used to send control instructions to the line status check module, insulation test module, discharge module, signal indication module, touch screen module and line control module; receive test data and status information of the line status check module, insulation test module, discharge module, signal indication module, touch screen module and line control module, and process data;

[0009] The circuit status check module is used to check whether the circuit under test has power supply access, whether the test circuit is short-circuited, and whether the discharge is completed after the test is completed;

[0010] The insulation test module is used to output high voltage for insulation testing. The output voltage is stepped from V1, V2, V3, V4 to V5, and the leakage current is monitored in real time. The insulation test module has a built-in current limiting unit.

[0011] The discharge module is used to discharge the tested circuit before and after the insulation test to prevent the capacitor in the circuit from being charged and causing electric shock accidents;

[0012] Signal indication module, used to indicate insulation test status, high voltage output or test abnormality;

[0013] Touch screen module, used to display test information, receive and send control instructions;

[0014] The line control module is composed of multiple relays and is used to control the connection and disconnection of related lines.

[0015] Specifically, the main control module includes a minimum system with a microcontroller ATMEGA328 as the core and a digital-to-analog conversion unit. Pins 1, 2, 9, 10, and 11 of the microcontroller are respectively connected to five relay control terminals of the line control module, pins 7 and 8 of the microcontroller are connected to a 7.3728MHZ crystal oscillator, pins 12 and 13 of the microcontroller are connected to an indicator light and a buzzer drive circuit of a signal indication module, pins 14, 15, and 17 of the microcontroller are connected to a DAC8853 of the digital-to-analog conversion unit, pins 23 and 24 of the microcontroller are connected to a signal acquisition unit ADS1112 of a line status check module, pin 29 of the microcontroller is connected to a reset circuit, and pins 30 and 31 of the microcontroller are connected to a touch screen module.

[0016] Specifically, the digital-to-analog conversion unit of the main control module mainly includes DAC8830 and OPA277, which are used to convert the microcontroller digital signal instructions into 0-5V analog voltage instructions to the high-voltage module, that is, the output end is connected to the high-voltage output circuit of the insulation test module.

[0017] Specifically, the signal acquisition unit of the line status check module includes ADS1112 and TL081, the acquisition port AIN0 of ADS1112 is connected to the emitter follower formed by TL081 for acquiring insulation test results, the acquisition port AIN1 of ADS1112 is connected to the resistance test circuit of the resistance detection unit for acquiring line resistance, the acquisition port AIN2 of ADS1112 is connected to the internal voltage detection unit of the insulation test module for acquiring high voltage output, and the acquisition port AIN3 of ADS1112 is connected to the voltage test circuit of the voltage detection unit for acquiring line voltage.

[0018] Specifically, the line control module includes relay 1, relay 2, relay 3, relay 4, and relay 5, all of which are normally open relays with the same control circuit and control ends connected to the microcontroller; one of the two contacts of relay 1 is connected to the voltage inspection unit of the line status inspection module, and the other is connected to the line under test; one of the two contacts of relay 2 is connected to the discharge module, and the other is connected to the line under test; the two contacts of relay 3 are connected to the power supply of the insulation test module; one of the two contacts of relay 4 is connected to the high-voltage output circuit of the insulation test module, and the other is connected to the insulation resistance measurement circuit; one of the two contacts of relay 4 is connected to the resistance inspection unit of the line status inspection module, and the other is connected to the line under test.

[0019] Specifically, the signal indication module includes an indicator light and a buzzer, and its driving circuit is similar to a relay control circuit, and the control end is connected to a microcontroller.

[0020] Specifically, the built-in current limiting unit of the insulation test module limits the maximum output current to 5mA; the ratio of the high voltage output circuit of the insulation test module to the input control signal voltage is 100; the action response time of the line control module relay closing and opening should be less than 3ms.

[0021] 8. The cable insulation test circuit according to claim 1, characterized in that the voltage range of V1 is 40-60V, the voltage range of V2 is 90-110V, the voltage range of V3 is 190-210V, the voltage range of V4 is 340-360V, and the voltage range of V5 is 490-510V.

[0022] In a second aspect, the present application provides a cable insulation testing method, the method comprising:

[0023] Step 1: After connecting the tested circuit to the test circuit, send instructions to the main control module through the touch screen, and the touch screen jumps to the circuit inspection interface and displays the inspection information;

[0024] Step 2: The main control module sends a control signal to the line status check module and the line control module, the line control module relay 1 is energized, and the voltage check unit of the line status check module is connected to the line under test;

[0025] Step 3: If the voltage of the tested line is normal or the voltage of the tested line can drop to zero after discharge, relay 1 and relay 2 are disconnected, relay 5 is connected, and the resistance inspection unit of the line status inspection module is connected to the tested line. If the tested line is short-circuited, the main control module sends a command to the line control module, relay 5 is disconnected, and the main control module sends a command to the signal indication module. The signal indicator light flashes and the buzzer sounds. The operator needs to check and restart the test;

[0026] Step 4: If the resistance inspection unit is normal, the main control module sends a command to the line control module, and relay 1 and relay 2 are energized to complete the circuit discharge;

[0027] Step 5: The main control module sends a command to the touch screen module, and the touch screen jumps to the insulation test interface and displays the status information; the main control module sends a command to the line control module, relay 1 and relay 2 are disconnected, relay 3 is closed, and the insulation test module is powered on;

[0028] Step 6: The main control module sends an instruction to the insulation test module, and the insulation test module starts to output V1 voltage. The internal voltage monitoring unit of the insulation test module monitors the real-time output voltage. After confirming that the accuracy is met, a feedback signal is sent to the main control module. The main control module sends an instruction to the line control module, relay 4 is energized, and the high-voltage output circuit of the insulation test module is connected to the measured line. The internal voltage monitoring unit and the leakage current monitoring unit of the insulation test module monitor in real time. If the line is normal, the voltage of V1, V2, V3, V4, and V5 is increased in sequence in a step-by-step manner. Once an abnormality occurs, a feedback signal is immediately sent to the main control module. The main control module sends an instruction to the line control module, relay 3 and relay 4 are disconnected, and the main control module sends an instruction to the signal indication module. The signal indicator light flashes and the buzzer sounds.

[0029] Step 7: After the insulation test is completed, the main control module sends instructions to the line control module, relay 1 and relay 2 are energized, and relay 3 and relay 4 are disconnected. After the circuit discharge is completed, the main control module sends the test results to the touch screen for display.

[0030] Specifically, step 2 also includes:

[0031] If the voltage of the tested line is found to be abnormal, a signal is sent to the main control module. After receiving the signal, the main control module sends an instruction to the line control module, relay 2 is energized, and the discharge module circuit is connected to the tested line. The voltage of the tested line does not drop, indicating whether there is an external power supply in the tested line that is not disconnected. The main control module sends an instruction to the line control module, relay 1 and relay 2 are disconnected, and the main control module sends an instruction to the signal indication module. The signal indicator light flashes and the buzzer sounds. The operator needs to check and restart the test.

[0032] In summary, the present application provides a cable insulation test circuit. The line inspection and automatic discharge before and after the insulation test can effectively reduce the line damage caused by operator errors. The stepped boost high voltage output of the insulation test and the real-time monitoring of the leakage current and output voltage can effectively reduce the line damage caused by poor insulation of the tested line or wiring errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of a cable insulation test circuit provided in this application;

[0034] Figure 2 A minimum system schematic diagram of a main control module provided for this application;

[0035] Figure 3 A schematic diagram of a digital-to-analog conversion unit of a main control module provided in this application;

[0036] Figure 4 A schematic diagram of a signal acquisition unit of a line status check module provided in this application;

[0037] Figure 5 A relay control schematic diagram of a line control module provided in this application;

[0038] Figure 6 A buzzer control schematic diagram of a signal indication module provided in this application;

[0039] Figure 7 A schematic diagram of the indicator light control principle of a signal indication module provided in this application. DETAILED DESCRIPTION

[0040] Purpose of the invention: The present invention provides an insulation test circuit and a test method for aircraft cables, which can identify test risks and avoid the continuous high voltage output of the insulation test from damaging electronic components in the circuit.

[0041] Embodiment 1

[0042] like Figure 1As shown, the present application provides a cable insulation test circuit, including a main control module, a line status check module, an insulation test module, a discharge module, a signal indication module, a touch screen module, and a line control module, wherein:

[0043] The input end of the main control module is connected to the touch screen module, and the output end of the main control module is respectively connected to the line status inspection module, the insulation test module, the discharge module, the signal indication module, the touch screen module and the line control module;

[0044] The main control module is used to send control instructions to the line status check module, insulation test module, discharge module, signal indication module, touch screen module and line control module; receive test data and status information of the line status check module, insulation test module, discharge module, signal indication module, touch screen module and line control module, and process data;

[0045] The circuit status check module is used to check whether the circuit under test has power supply access, whether the test circuit is short-circuited, and whether the discharge is completed after the test is completed;

[0046] The insulation test module is used to output high voltage for insulation testing. The output voltage is stepped from V1, V2, V3, V4 to V5, and the leakage current is monitored in real time. The insulation test module has a built-in current limiting unit.

[0047] The discharge module is used to discharge the tested circuit before and after the insulation test to prevent the capacitor in the circuit from being charged and causing electric shock accidents;

[0048] Signal indication module, used to indicate insulation test status, high voltage output or test abnormality;

[0049] The touch screen module is used to display test information, receive and send control instructions.

[0050] The line control module is composed of multiple relays and is used to control the connection and disconnection of related lines.

[0051] Specifically, Figure 2As shown, the main control module includes a minimum system with a microcontroller ATMEGA328 as the core and a digital-to-analog conversion unit, pins 1, 2, 9, 10, and 11 of the microcontroller are respectively connected to 5 relay control terminals of the line control module, pins 7 and 8 of the microcontroller are connected to a 7.3728MHZ crystal oscillator, pins 12 and 13 of the microcontroller are connected to the indicator light and buzzer drive circuit of the signal indication module, pins 14, 15, and 17 of the microcontroller are connected to DAC8853 of the digital-to-analog conversion unit, pins 23 and 24 of the microcontroller are connected to a signal acquisition unit ADS1112 of a line status check module, pin 29 of the microcontroller is connected to a reset circuit, and pins 30 and 31 of the microcontroller are connected to a touch screen module.

[0052] Specifically, Figure 3 As shown, the digital-to-analog conversion unit of the main control module mainly includes DAC8830 and OPA277, which are used to convert the microcontroller digital signal instructions into 0-5V analog voltage instructions to the high-voltage module, that is, the output end is connected to the high-voltage output circuit of the insulation test module.

[0053] Specifically, Figure 4 As shown, the signal acquisition unit of the line status check module includes ADS1112 and TL081, the acquisition port AI N0 of ADS1112 is connected to the emitter follower formed by TL081, and is used to collect insulation test results, the acquisition port AI N1 of ADS1112 is connected to the resistance test circuit of the resistance detection unit, and is used to collect line resistance, the acquisition port AI N2 of ADS1112 is connected to the internal voltage detection unit of the insulation test module, and is used to collect high voltage output, and the acquisition port AI N3 of ADS1112 is connected to the voltage test circuit of the voltage detection unit, and is used to collect line voltage.

[0054] Specifically, Figure 5 As shown, the line control module includes relay 1, relay 2, relay 3, relay 4, and relay 5, all of which are normally open relays, and their control circuits are the same, and the control ends are all connected to the microcontroller. One of the two contacts of relay 1 is connected to the voltage inspection unit of the line status inspection module, and the other is connected to the line under test. One of the two contacts of relay 2 is connected to the discharge module, and the other is connected to the line under test. The two contacts of relay 3 are connected to the power supply of the insulation test module. One of the two contacts of relay 4 is connected to the high-voltage output circuit of the insulation test module, and the other is connected to the insulation resistance measurement circuit. One of the two contacts of relay 4 is connected to the resistance inspection unit of the line status inspection module, and the other is connected to the line under test.

[0055] Specifically, Figure 6-7As shown, the signal indication module includes an indicator light and a buzzer, and its driving circuit is similar to a relay control circuit, and the control ends are connected to a microcontroller.

[0056] Specifically, the insulation test module has a built-in current limiting unit that can limit the maximum output current to 5 mA.

[0057] Specifically, the ratio of the high voltage output of the high voltage output circuit of the insulation test module to the input control signal voltage is 100.

[0058] Specifically, the action response time of the line control module relay closing and opening should be less than 3ms.

[0059] Specifically, the voltage range of V1 is 40-60V, the voltage range of V2 is 90-110V, the voltage range of V3 is 190-210V, the voltage range of V4 is 340-360V, and the voltage range of V5 is 490-510V.

[0060] Specifically, the touch screen module can display the current working status of the circuit, the inspection results of the line status inspection module, the insulation test results, the working status of the high-voltage output circuit in the insulation test mode, the on-off status of the five relays of the line control module, whether the test is abnormal, etc.

[0061] In summary, the present application provides a cable insulation test circuit. The line inspection and automatic discharge before and after the insulation test can effectively reduce the line damage caused by operator errors. The stepped boost high voltage output of the insulation test and the real-time monitoring of the leakage current and output voltage can effectively reduce the line damage caused by poor insulation of the tested line or wiring errors.

[0062] Embodiment 2

[0063] The present application provides a cable insulation testing method, which is implemented using the cable insulation testing circuit provided in the above embodiment, and the method includes:

[0064] Step 1: After connecting the tested circuit to the test circuit, send instructions to the main control module through the touch screen, and the touch screen jumps to the circuit inspection interface and displays the inspection information;

[0065] Step 2: The main control module sends a control signal to the line status check module and the line control module, the line control module relay 1 is energized, and the voltage check unit of the line status check module is connected to the line under test;

[0066] If the voltage of the tested line is found to be abnormal, a signal is sent to the main control module. After receiving the signal, the main control module sends an instruction to the line control module, relay 2 is energized, and the discharge module circuit is connected to the tested line. The voltage of the tested line does not drop, indicating whether there is an external power supply in the tested line that is not disconnected. The main control module sends an instruction to the line control module, relay 1 and relay 2 are disconnected, and the main control module sends an instruction to the signal indication module. The signal indicator light flashes and the buzzer sounds. The operator needs to check and restart the test.

[0067] Step 3: If there is no abnormality in the voltage of the measured line or the voltage of the measured line can drop to zero after discharge, relay 1 and relay 2 are disconnected, relay 5 is connected, and the resistance inspection unit of the line status inspection module is connected to the measured line. If the measured line is short-circuited, the main control module sends a command to the line control module, relay 5 is disconnected, and the main control module sends a command to the signal indication module. The signal indicator light flashes and the buzzer sounds. The operator needs to check and restart the test.

[0068] Step 4: If the resistance inspection unit is normal, the main control module sends a command to the line control module, and relay 1 and relay 2 are energized to complete the circuit discharge.

[0069] Step 5: The main control module sends a command to the touch screen module, and the touch screen jumps to the insulation test interface and displays the status information. The main control module sends a command to the line control module, relays 1 and 2 are disconnected, relay 3 is closed, and the insulation test module is powered on.

[0070] Step 6: The main control module sends an instruction to the insulation test module, and the insulation test module starts to output V1 voltage. The internal voltage monitoring unit of the insulation test module monitors the real-time output voltage. After confirming that the accuracy is met, a feedback signal is sent to the main control module. The main control module sends an instruction to the line control module, relay 4 is energized, and the high-voltage output circuit of the insulation test module is connected to the measured line. The internal voltage monitoring unit and leakage current monitoring unit of the insulation test module monitor in real time. If the line is normal, the voltage of V1, V2, V3, V4, and V5 increases in sequence in a step-by-step manner. Once an abnormality occurs, a feedback signal is immediately sent to the main control module. The main control module sends an instruction to the line control module, relay 3 and relay 4 are disconnected, and the main control module sends an instruction to the signal indication module. The signal indicator light flashes and the buzzer sounds.

[0071] Step 7: After the insulation test is completed, the main control module sends instructions to the line control module, relay 1 and relay 2 are energized, and relay 3 and relay 4 are disconnected. After the circuit discharge is completed, the main control module sends the test results to the touch screen for display.

[0072] In summary, the present application provides a cable insulation test circuit. The line inspection and automatic discharge before and after the insulation test can effectively reduce the line damage caused by operator errors. The stepped boost high voltage output of the insulation test and the real-time monitoring of the leakage current and output voltage can effectively reduce the line damage caused by poor insulation of the tested line or wiring errors.

Claims

1. A cable insulation test circuit, characterized in that: It includes a main control module, a line status inspection module, an insulation test module, a discharge module, a signal indication module, a touch screen module, and a line control module, among which: The input end of the main control module is connected to the touch screen module, and the output end of the main control module is respectively connected to the line status inspection module, the insulation test module, the discharge module, the signal indication module, the touch screen module and the line control module; The main control module is used to send control instructions to the line status check module, insulation test module, discharge module, signal indication module, touch screen module and line control module; receive test data and status information of the line status check module, insulation test module, discharge module, signal indication module, touch screen module and line control module, and process data; The circuit status check module is used to check whether the circuit under test has power supply access, whether the test circuit is short-circuited, and whether the discharge is completed after the test is completed; The insulation test module is used to output high voltage for insulation testing. The output voltage is stepped from V1, V2, V3, V4 to V5, and the leakage current is monitored in real time. The insulation test module has a built-in current limiting unit. The discharge module is used to discharge the tested circuit before and after the insulation test to prevent the capacitor in the circuit from being charged and causing electric shock accidents; Signal indication module, used to indicate insulation test status, high voltage output or test abnormality; Touch screen module, used to display test information, receive and send control instructions; The line control module is composed of multiple relays and is used to control the connection and disconnection of related lines.

2. The cable insulation test circuit according to claim 1, characterized in that: The main control module includes a minimum system with a microcontroller ATMEGA328 as the core and a digital-to-analog conversion unit. Pins 1, 2, 9, 10, and 11 of the microcontroller are respectively connected to five relay control terminals of the line control module, pins 7 and 8 of the microcontroller are connected to a 7.3728MHZ crystal oscillator, pins 12 and 13 of the microcontroller are connected to an indicator light and a buzzer drive circuit of a signal indication module, pins 14, 15, and 17 of the microcontroller are connected to a DAC8853 of the digital-to-analog conversion unit, pins 23 and 24 of the microcontroller are connected to a signal acquisition unit ADS1112 of a line status check module, pin 29 of the microcontroller is connected to a reset circuit, and pins 30 and 31 of the microcontroller are connected to a touch screen module.

3. The cable insulation test circuit according to claim 1, characterized in that: The digital-to-analog conversion unit of the main control module mainly includes DAC8830 and OPA277, which are used to convert the microcontroller digital signal instructions into 0-5V analog voltage instructions to the high-voltage module, that is, the output end is connected to the high-voltage output circuit of the insulation test module.

4. The cable insulation test circuit according to claim 1, characterized in that: The signal acquisition unit of the line status inspection module includes ADS1112 and TL081. The acquisition port AIN0 of the ADS1112 is connected to the emitter follower formed by TL081 for acquiring insulation test results. The acquisition port AIN1 of the ADS1112 is connected to the resistance test circuit of the resistance detection unit for acquiring line resistance. The acquisition port AIN2 of the ADS1112 is connected to the internal voltage detection unit of the insulation test module for acquiring high voltage output. The acquisition port AIN3 of the ADS1112 is connected to the voltage test circuit of the voltage detection unit for acquiring line voltage.

5. The cable insulation test circuit according to claim 1, characterized in that: The line control module includes relay 1, relay 2, relay 3, relay 4, and relay 5, all of which are normally open relays, have the same control circuit, and control ends are all connected to the microcontroller; one of the two contacts of relay 1 is connected to the voltage inspection unit of the line status inspection module, and the other is connected to the measured line; one of the two contacts of relay 2 is connected to the discharge module, and the other is connected to the measured line; the two contacts of relay 3 are connected to the power supply of the insulation test module; one of the two contacts of relay 4 is connected to the high-voltage output circuit of the insulation test module, and the other is connected to the insulation resistance measurement circuit; one of the two contacts of relay 4 is connected to the resistance inspection unit of the line status inspection module, and the other is connected to the measured line.

6. The cable insulation test circuit according to claim 1, characterized in that: The signal indication module comprises an indicator light and a buzzer, and its driving circuit is similar to a relay control circuit, and the control ends are connected to a microcontroller.

7. The cable insulation test circuit according to claim 1, characterized in that: The built-in current limiting unit of the insulation test module limits the maximum output current to 5mA; the ratio of the high voltage output circuit of the insulation test module to the input control signal voltage is 100; the action response time of the line control module relay closing and opening should be less than 3ms.

8. The cable insulation test circuit according to claim 1, characterized in that: The voltage range of V1 is 40-60V, the voltage range of V2 is 90-110V, the voltage range of V3 is 190-210V, the voltage range of V4 is 340-360V, and the voltage range of V5 is 490-510V.

9. A cable insulation testing method, characterized in that: Methods include: Step 1: After connecting the circuit under test to the test circuit, send instructions to the main control module through the touch screen, and the touch screen jumps to the circuit inspection interface and displays the inspection information; Step 2: The main control module sends a control signal to the line status check module and the line control module, the line control module relay 1 is energized, and the voltage check unit of the line status check module is connected to the line under test; Step 3: If the voltage of the tested line is normal or the voltage of the tested line can drop to zero after discharge, relay 1 and relay 2 are disconnected, relay 5 is connected, and the resistance inspection unit of the line status inspection module is connected to the tested line. If the tested line is short-circuited, the main control module sends a command to the line control module, relay 5 is disconnected, and the main control module sends a command to the signal indication module. The signal indicator light flashes and the buzzer sounds. The operator needs to check and restart the test; Step 4: If the resistance inspection unit is normal, the main control module sends a command to the line control module, and relay 1 and relay 2 are energized to complete the circuit discharge; Step 5: The main control module sends a command to the touch screen module, and the touch screen jumps to the insulation test interface and displays the status information; the main control module sends a command to the line control module, relay 1 and relay 2 are disconnected, relay 3 is closed, and the insulation test module is powered on; Step 6: The main control module sends an instruction to the insulation test module, and the insulation test module starts to output V1 voltage. The internal voltage monitoring unit of the insulation test module monitors the real-time output voltage. After confirming that the accuracy is met, a feedback signal is sent to the main control module. The main control module sends an instruction to the line control module, relay 4 is energized, and the high-voltage output circuit of the insulation test module is connected to the measured line. The internal voltage monitoring unit and the leakage current monitoring unit of the insulation test module monitor in real time. If the line is normal, the voltage of V1, V2, V3, V4, and V5 is increased in sequence in a step-by-step manner. Once an abnormality occurs, a feedback signal is immediately sent to the main control module. The main control module sends an instruction to the line control module, relay 3 and relay 4 are disconnected, and the main control module sends an instruction to the signal indication module. The signal indicator light flashes and the buzzer sounds. Step 7: After the insulation test is completed, the main control module sends instructions to the line control module, relay 1 and relay 2 are energized, and relay 3 and relay 4 are disconnected. After the circuit discharge is completed, the main control module sends the test results to the touch screen for display.

10. The method according to claim 9, characterized in that Step 2 also includes: If the voltage of the tested line is found to be abnormal, a signal is sent to the main control module. After receiving the signal, the main control module sends an instruction to the line control module, relay 2 is energized, and the discharge module circuit is connected to the tested line. The voltage of the tested line does not drop, indicating whether there is an external power supply in the tested line that is not disconnected. The main control module sends an instruction to the line control module, relay 1 and relay 2 are disconnected, and the main control module sends an instruction to the signal indication module. The signal indicator light flashes and the buzzer sounds. The operator needs to check and restart the test.

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