Anti-reverse power transmission insulation resistance testing device

Abstract

The utility model discloses an anti-reverse power transmission insulation resistance testing device, which comprises a high-voltage switch, an insulation resistance measuring module, an alternating voltage measuring module, an anti-reverse power transmission module and a main control module, wherein the reverse power transmission prevention module is used for judging whether reverse power transmission occurs or not according to the voltage of an alternating current signal acquired by the alternating current voltage measurement module, and controlling the high-voltage switch to cut off a connection path between the high-voltage output end and a measured line when reverse power transmission occurs; the main control module is used for controlling the magnitude of the direct-current high voltage provided by the direct-current high-voltage module, the measuring gear of the insulation resistance measuring module and the opening / closing of the high-voltage switch, and determining the insulation resistance of the measured line according to the insulation resistance measuring data acquired by the insulation resistance measuring module; therefore, the insulation resistance of the tested line can be measured, the reverse power transmission condition can be prevented in the testing process, and the electric shock risk of high-voltage line maintenance workers is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of power distribution maintenance safety, in particular to an insulation resistance test device for preventing reverse power transmission. Background Art

[0002] During line maintenance work, an insulation resistance tester is required to measure the line's insulation resistance to ground. However, since the grounding hook on the line must be removed when using the tester, if abnormal reverse power flow occurs, the high-voltage power supply will directly act on the insulation resistance tester through the test leads, which can easily cause electric shock accidents to operators. Therefore, it is necessary to provide an insulation resistance tester with anti-reverse power flow function to reduce the risk of electric shock for high-voltage line maintenance workers. Utility Model Content

[0003] The purpose of the utility model is to provide an anti-backward power transmission insulation resistance test device, which monitors and prevents the backward power transmission state during the test process while realizing the measurement of the insulation resistance value of the tested line to the ground, thereby reducing the risk of electric shock for high-voltage line maintenance workers.

[0004] In order to achieve the above-mentioned purpose of the utility model, the utility model provides the following technical solutions:

[0005] A device for testing insulation resistance against reverse power transmission, comprising:

[0006] A high-voltage switch is provided on the connection path between the high-voltage output terminal and the circuit under test;

[0007] A DC high voltage module, used for providing DC high voltage to the circuit under test via the high voltage output terminal;

[0008] Insulation resistance measurement module, used to collect insulation resistance measurement data of the measured circuit;

[0009] an AC voltage measurement module, configured to collect the voltage of the AC signal on the connection path;

[0010] an anti-backward power transmission module, configured to determine whether backward power transmission occurs based on the voltage of the AC signal collected by the AC voltage measurement module, and control the high-voltage switch to cut off the connection path between the high-voltage output terminal and the measured circuit when backward power transmission occurs;

[0011] The main control module is used to control the magnitude of the DC high voltage provided by the DC high-voltage module, the measurement position of the insulation resistance measurement module, and the opening / closing of the high-voltage switch, and to determine the insulation resistance of the measured circuit based on the insulation resistance measurement data collected by the insulation resistance measurement module.

[0012] According to a specific embodiment, in the anti-backward power transmission insulation resistance test device provided by the present invention, the DC high-voltage module includes: a battery unit, a PWM modulation unit, an inverter unit, a boost conversion unit, a low-pass filter unit and a voltage feedback unit; wherein,

[0013] The PWM modulation unit is used to output a PWM modulation signal according to the first control signal of the main control module or the feedback signal provided by the voltage feedback unit;

[0014] The inverter unit is configured to convert the direct current provided by the battery unit into alternating current according to the PWM modulation signal output by the PWM modulation unit;

[0015] The boost conversion unit is used to perform voltage doubling and DC conversion operations on the AC power output by the inverter unit to output DC high voltage;

[0016] The low-pass filter unit is used to perform low-pass filtering on the DC high voltage output by the boost conversion unit;

[0017] The voltage feedback unit is used to generate a corresponding feedback signal according to the DC high voltage processed by the low-pass filter unit.

[0018] According to a specific embodiment, in the anti-backflow insulation resistance test device provided by the present invention, the insulation resistance measurement module includes: an AD conversion chip, a multi-way analog switch and a plurality of different sampling bridges; wherein the multi-way analog switch is respectively connected to each of the sampling bridges, and according to the second control signal output by the main control module, the corresponding sampling bridge is selected to be connected to the measurement path; the AD conversion chip is used to convert the voltage signal collected by the sampling bridge into the insulation resistance measurement data.

[0019] According to a specific embodiment, in the anti-backflow insulation resistance testing device provided by the present invention, the AC voltage measurement module includes: a voltage transformer, a rectifier bridge, an LC resonant filter sub-circuit, an operational amplifier sub-circuit, and a voltage clamping sub-circuit; wherein, the high-voltage side of the primary winding of the voltage transformer is connected to the connection path, and the low-voltage side of the primary winding is grounded; the high-voltage side and the low-voltage side of the secondary winding of the voltage transformer are respectively connected to the two AC input ends of the rectifier bridge; the output end of the rectifier bridge is connected to the operational amplifier sub-circuit through the LC resonant filter sub-circuit; the LC resonant filter sub-circuit is configured to have a resonant frequency of 50 Hz to allow the power frequency signal to pass through; the operational amplifier sub-circuit is used to amplify the voltage signal passing through the LC resonant filter sub-circuit; the voltage clamping sub-circuit is connected to the output end of the operational amplifier sub-circuit to clamp the voltage output by the operational amplifier sub-circuit.

[0020] According to a specific embodiment, in the anti-backflow insulation resistance testing device provided by the utility model, the anti-backflow module includes: a microcontroller, which is used to perform AD conversion on the voltage signal output by the operational amplifier sub-circuit to obtain voltage data, and judge whether the voltage data exceeds a set threshold. If the set threshold is reached, a control signal is output to cause the high-voltage switch to cut off the connection path between the high-voltage output end and the circuit under test.

[0021] According to a specific embodiment, in the anti-backward power supply insulation resistance testing device provided by the present invention, the main control module is a single-chip microcomputer; and the single-chip microcomputer is connected to the microcontroller.

[0022] According to a specific embodiment, the anti-backward power supply insulation resistance testing device provided by the present invention also includes: a display interaction module; and the display interaction module is connected to the main control module to display the insulation resistance value, the DC high voltage value, the set threshold and the voltage value of the AC signal, or set the operating parameters of the main control module according to the interactive operation.

[0023] According to a specific embodiment, the anti-backward power supply insulation resistance testing device provided by the present invention also includes: an alarm module; the alarm module is connected to the main control module to issue an alarm based on the device operation status and backward power supply status monitored by the main control module.

[0024] According to a specific embodiment, in the anti-backflow insulation resistance testing device provided by the present invention, the display interaction module is a capacitive touch screen; the alarm module includes: one or more status indicator lights, and / or, one or more buzzers.

[0025] According to a specific embodiment, in the anti-backward power transmission insulation resistance testing device provided by the present invention, the battery unit is also used to provide power for the main control module, the anti-backward power transmission module, the display interaction module and the alarm module.

[0026] In this way, the anti-backward power insulation resistance testing device provided by the utility model, by setting a high-voltage switch, an insulation resistance measurement module, an AC voltage measurement module, an anti-backward power module and a main control module, can not only measure the insulation resistance of the tested line, but also determine whether backward power occurs during the test process, and then prevent backward power, thereby reducing the risk of electric shock for high-voltage line maintenance workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a connection diagram of the anti-backflow insulation resistance test device provided by the utility model;

[0028] Figure 2This is a schematic diagram of the internal connections of the DC high voltage module in the present invention;

[0029] Figure 3 This is a schematic diagram of the internal connections of the insulation resistance measurement module of the present invention;

[0030] Figure 4 This is a circuit connection diagram of the AC voltage measurement module of the present utility model;

[0031] Figure 5 FIG. 1 is a connection diagram of an anti-backward power transmission insulation resistance test device in a specific embodiment. DETAILED DESCRIPTION

[0032] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments. All technologies implemented based on the present invention fall within the scope of the present invention.

[0033] like Figure 1 As shown, the utility model provides an anti-backward power supply insulation resistance test device, which includes:

[0034] A high-voltage switch is provided on the connection path between the high-voltage output terminal and the circuit under test;

[0035] A DC high voltage module, used for providing DC high voltage to the circuit under test via the high voltage output terminal;

[0036] Insulation resistance measurement module, used to collect insulation resistance measurement data of the measured circuit;

[0037] an AC voltage measurement module, configured to collect the voltage of the AC signal on the connection path;

[0038] an anti-backward power transmission module, configured to determine whether backward power transmission occurs based on the voltage of the AC signal collected by the AC voltage measurement module, and control the high-voltage switch to cut off the connection path between the high-voltage output terminal and the measured circuit when backward power transmission occurs;

[0039] The main control module is used to control the magnitude of the DC high voltage provided by the DC high-voltage module, the measurement position of the insulation resistance measurement module, and the opening / closing of the high-voltage switch, and to determine the insulation resistance of the measured circuit based on the insulation resistance measurement data collected by the insulation resistance measurement module.

[0040] Specifically, before measuring the insulation resistance of the circuit under test, first connect the test lead to one end of the high-voltage switch and connect the ground lead to the ground end; then, start the measurement, the main control module controls the high-voltage switch to connect the high-voltage output end and the circuit under test, and at the same time, the main control module controls the DC high-voltage module to generate DC high voltage, and applies it to the circuit under test through the connection path; then, during the measurement process, the main control module controls the measurement gear of the insulation resistance measurement module and selects the appropriate measurement gear to complete the test; at the same time, the anti-backward power supply module determines in real time whether backward power supply occurs, and then takes precautions against backward power supply, that is, disconnects the high-voltage switch, cuts off the connection path between the high-voltage output end and the circuit under test, and stops the test. Among them, the measurement input ends of the insulation resistance measurement module and the AC voltage measurement module are both connected to the high-voltage output end, and the grounding parts are both connected to the ground end of the device, and are grounded through the ground lead.

[0041] like Figure 2 As shown, in the anti-backward power transmission insulation resistance test device provided by the present invention, the DC high-voltage module includes: a battery unit, a PWM modulation unit, an inverter unit, a boost conversion unit, a low-pass filter unit and a voltage feedback unit; wherein,

[0042] The PWM modulation unit is used to output a PWM modulation signal according to the first control signal of the main control module or the feedback signal provided by the voltage feedback unit;

[0043] The inverter unit is configured to convert the direct current provided by the battery unit into alternating current according to the PWM modulation signal output by the PWM modulation unit;

[0044] The boost conversion unit is used to perform voltage doubling and DC conversion operations on the AC power output by the inverter unit to output DC high voltage;

[0045] The low-pass filter unit is used to perform low-pass filtering on the DC high voltage output by the boost conversion unit;

[0046] The voltage feedback unit is used to generate a corresponding feedback signal according to the DC high voltage processed by the low-pass filter unit.

[0047] Therefore, in the anti-backward power supply insulation resistance test device provided by the present invention, the DC high-voltage module can be controlled by the main control module to generate multiple levels of DC voltages such as 250V, 500V, 1000V, and 2500V; at the same time, by setting a suitable cut-off frequency of the low-pass filter unit, the high-frequency interference of the previous stage can be filtered out, thereby obtaining a more stable DC high voltage and improving the measurement accuracy; moreover, the PWM modulation unit can dynamically adjust the PWM pulse width according to the currently output DC high voltage, and then dynamically adjust the output DC voltage, thereby ensuring the stability of the DC high voltage output during the measurement process and effectively improving the accuracy of the insulation resistance test results.

[0048] like Figure 3 In the anti-backflow insulation resistance test device provided by the present invention, the insulation resistance measurement module includes: an AD conversion chip, a multi-way analog switch and a plurality of different sampling bridges; wherein the multi-way analog switch is respectively connected to each of the sampling bridges, and according to the second control signal output by the main control module, the corresponding sampling bridge is selected to be connected to the measurement path, thereby applying the input voltage to the corresponding sampling bridge, and inputting the voltage signal collected by it into the AD conversion chip, and finally, the AD conversion chip converts the voltage signal collected by the sampling bridge into the insulation resistance measurement data.

[0049] like Figure 4 As shown, in the anti-backflow insulation resistance test device provided by the present invention, the AC voltage measurement module includes: a voltage transformer PT, a rectifier bridge B1, an LC resonant filter sub-circuit, an operational amplifier sub-circuit, and a voltage clamping sub-circuit; wherein, the high-voltage side of the primary winding of the voltage transformer PT is connected to the connection path, and the low-voltage side of the primary winding is grounded; the high-voltage side and the low-voltage side of the secondary winding of the voltage transformer PT are respectively connected to the two AC input ends of the rectifier bridge B1; the output end of the rectifier bridge is connected to the operational amplifier sub-circuit through the LC resonant filter sub-circuit; the LC resonant filter sub-circuit is configured to have a resonant frequency of 50 Hz so as to allow the power frequency signal to pass through; the operational amplifier sub-circuit is used to amplify the voltage signal passing through the LC resonant filter sub-circuit; the voltage clamping sub-circuit is connected to the output end of the operational amplifier sub-circuit to clamp the voltage output by the operational amplifier sub-circuit.

[0050] Specifically, the voltage transformer PT is used to sense the line AC voltage and at the same time filter out the DC high voltage used to measure the insulation resistance, ensuring that the measured voltage signal comes from the AC voltage generated by the reverse power transmission; the rectifier bridge B1 converts the AC signal output by the voltage transformer PT into a pulsating DC signal, which is convenient for the subsequent anti-reverse power transmission module to perform sampling; the inductor L1 and the capacitor C1 form an LC resonant filter sub-circuit, and the parameters of the inductor L1 and the capacitor C1 are adjusted to adjust their resonant frequency to 50Hz to allow the power frequency signal to pass, thereby improving measurement accuracy and reducing interference; the operational amplifier sub-circuit composed of the operational amplifier U1, resistors R1 and R2 amplifies the voltage signal at a low magnification and acts as an isolation function at the same time; the resistor R4 and the diode D1 form a voltage clamping sub-circuit, which clamps the output voltage of the AC voltage measurement module to VCC to prevent abnormally high voltage from damaging subsequent modules.

[0051] like Figure 5As shown, in the anti-backflow insulation resistance test device provided by the present invention, the anti-backflow module includes: a microcontroller, which is used to perform AD conversion on the voltage signal output by the operational amplifier sub-circuit to obtain voltage data, and judge whether the voltage data exceeds a set threshold. If the set threshold is reached, a control signal is output to cause the high-voltage switch to cut off the connection path between the high-voltage output end and the circuit under test.

[0052] In this way, the analog voltage signal output by the AC voltage measurement module is continuously converted into analogue-to-digital (AD) by the microcontroller, thereby measuring the dynamic amplitude of the AC voltage. At the same time, after each measurement, it is immediately determined whether it is a valid reverse power supply voltage, thereby disconnecting the high-voltage switch in the shortest possible time after a reverse power supply fault occurs.

[0053] Furthermore, the main control module is a single-chip microcomputer; the single-chip microcomputer is connected to the microcontroller to realize information interaction; and the display interaction module is connected to the main control module to display the insulation resistance value, the DC high voltage value, the set threshold and the voltage value of the AC signal, or set the operating parameters of the main control module according to the interactive operation; the alarm module is connected to the main control module to issue an alarm based on the device operating status and reverse power supply status monitored by the main control module.

[0054] During implementation, the display interaction module is a capacitive touch screen; the alarm module includes: one or more status indicator lights; and / or, one or more buzzers; the battery unit is also used to provide power for the main control module, anti-reverse power supply module, display interaction module and the alarm module.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device for testing insulation resistance against reverse power transmission, characterized in that: include: A high-voltage switch is provided on a connection path between the high-voltage output terminal and the circuit under test; A DC high voltage module, used for providing a DC high voltage to the circuit under test via the high voltage output terminal; Insulation resistance measurement module, used to collect insulation resistance measurement data of the measured circuit; An AC voltage measurement module, used for collecting the voltage of the AC signal on the connection path; an anti-reverse power transmission module, used to determine whether reverse power transmission occurs according to the voltage of the AC signal collected by the AC voltage measurement module, and control the high-voltage switch to cut off the connection path between the high-voltage output terminal and the measured line when reverse power transmission occurs; The main control module is used to control the size of the DC high voltage provided by the DC high voltage module, the measurement gear of the insulation resistance measurement module and the opening / closing of the high voltage switch, and determine the insulation resistance of the measured circuit according to the insulation resistance measurement data collected by the insulation resistance measurement module.

2. The anti-reverse power transmission insulation resistance test device according to claim 1, characterized in that: The DC high voltage module includes: a battery unit, a PWM modulation unit, an inverter unit, a boost conversion unit, a low-pass filter unit and a voltage feedback unit; wherein, The PWM modulation unit is used to output a PWM modulation signal according to the first control signal of the main control module or the feedback signal provided by the voltage feedback unit; The inverter unit is used to convert the direct current provided by the battery unit into alternating current according to the PWM modulation signal output by the PWM modulation unit; The boost conversion unit is used to perform voltage doubling operation and DC conversion operation on the AC power output by the inverter unit to output DC high voltage; The low-pass filter unit is used to perform low-pass filtering on the DC high voltage output by the boost conversion unit; The voltage feedback unit is used to generate a corresponding feedback signal according to the DC high voltage processed by the low-pass filter unit.

3. The anti-reverse power transmission insulation resistance test device according to claim 2, characterized in that: The insulation resistance measurement module includes: an AD conversion chip, a multi-way analog switch and a plurality of different sampling bridges; wherein the multi-way analog switch is respectively connected to each of the sampling bridges, and selects the corresponding sampling bridge to be connected to the measurement path according to the second control signal output by the main control module; the AD conversion chip is used to convert the voltage signal collected by the sampling bridge into the insulation resistance measurement data.

4. The anti-reverse power transmission insulation resistance test device according to claim 3, characterized in that: The AC voltage measurement module includes: a voltage transformer, a rectifier bridge, an LC resonant filter subcircuit, an operational amplifier subcircuit and a voltage clamping subcircuit; wherein, the high voltage side of the primary winding of the voltage transformer is connected to the connection path, and the low voltage side of the primary winding is grounded; the high voltage side and the low voltage side of the secondary winding of the voltage transformer are respectively connected to the two AC input ends of the rectifier bridge; the output end of the rectifier bridge is connected to the operational amplifier subcircuit through the LC resonant filter subcircuit; the LC resonant filter subcircuit is configured to have a resonant frequency of 50 Hz so that the industrial frequency signal can pass through; the operational amplifier subcircuit is used to amplify the voltage signal passing through the LC resonant filter subcircuit; the voltage clamping subcircuit is connected to the output end of the operational amplifier subcircuit to clamp the voltage output by the operational amplifier subcircuit.

5. The anti-reverse power transmission insulation resistance test device according to claim 4, characterized in that: The anti-reverse power transmission module includes: a microcontroller, which is used to perform AD conversion on the voltage signal output by the operational amplifier subcircuit to obtain voltage data, and determine whether the voltage data exceeds a set threshold. If the set threshold is reached, a control signal is output to enable the high-voltage switch to cut off the connection path between the high-voltage output terminal and the circuit under test.

6. The anti-reverse power transmission insulation resistance test device according to claim 5, characterized in that: The main control module is a single chip microcomputer; the single chip microcomputer is connected to the microcontroller.

7. The anti-reverse power transmission insulation resistance test device according to claim 6, characterized in that: Also includes: Display interaction module; moreover, the display interaction module is connected to the main control module to display the insulation resistance value, the DC high voltage value, the set threshold and the voltage value of the AC signal, or set the operating parameters of the main control module according to the interactive operation.

8. The anti-reverse power transmission insulation resistance test device according to claim 7, characterized in that: Also includes: Alarm module; the alarm module is connected to the main control module to issue an alarm based on the device operation status and reverse power supply status monitored by the main control module.

9. The anti-reverse power transmission insulation resistance test device according to claim 8, characterized in that: The display interaction module is a capacitive touch screen; the alarm module includes: one or more status indicator lights, and / or, one or more buzzers.

10. The anti-reverse power transmission insulation resistance test device according to claim 9, characterized in that: The battery unit is also used to provide power for the main control module, the anti-reverse power transmission module, the display interaction module and the alarm module.

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