Leakage current detection device for cable

Abstract

The invention relates to the technical field of leakage current detection, in particular to a leakage current detection device for a cable, and the device comprises a leakage current collection module which is used for detecting the leakage current of the cable through the leakage current detection device; the detection module comprises a voltage sensor used for detecting the working voltage of the leakage current detection device; the alarm module is used for giving an alarm when the leakage current exceeds a threshold value; the communication module is used for transmitting the filtered leakage current signal to the display module; the display module is connected with the communication module and is used for displaying the filtered leakage current signal; and the control module is connected with the leakage current acquisition module, the detection module, the alarm module, the communication module and the display module, and is used for determining the sampling frequency of the leakage current according to the variance of the fluctuation amplitude of the leakage current. The detection stability of the leakage current detection device is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of leakage current detection, and in particular to a leakage current detection device for a cable. Background Art

[0002] In order to ensure the safety of electricity use, all electrical equipment used in the field of power electronics technology must be tested for leakage current. The so-called leakage current refers to the conduction current flowing through the conductor when the conductor contacts the circuit of the electrical equipment. If the leakage current is too large, it will cause an electrical safety accident.

[0003] At present, the commonly used leakage current detection method is: let the leakage current detection circuit pass through a magnetic core, and apply positive and negative pulse voltages to the windings of the magnetic core, and then sample the time difference between the positive and negative saturation of the magnetic core, and finally calculate the leakage current on the leakage current detection circuit through the time difference. This detection method is not only cumbersome to operate, but also has a large error in calculating the leakage current value by sampling the time difference between the positive and negative saturation of the magnetic core. At the same time, the detection device circuit of this commonly used method is very complicated.

[0004] In order to solve the above problems, this solution provides a leakage current detection device for performing leakage current detection on electrical equipment. By implementing this product solution, the operation of leakage current detection on electrical equipment can be simplified, and the detection accuracy and reliability can be improved.

[0005] Chinese Patent Publication No.: CN109541287A discloses a leakage current detection device, including: an intermediate tap of the secondary winding of an isolation transformer, a thermistor PTC, a leakage current sampling resistor R2, an adjustment resistor R1, a bidirectional transient suppression tube TVS, a filter capacitor C1 and a bidirectional optical coupler U1, wherein the first end of the bidirectional transient suppression tube TVS is electrically connected to the intermediate tap of the secondary winding of the isolation transformer, the second end of the bidirectional transient suppression tube TVS is electrically connected to the first end of the thermistor PTC, the second end of the thermistor PTC is grounded, and the adjustment The first end of the resistor R1 is electrically connected to the first end of the bidirectional transient suppressor TVS, the second end of the regulating resistor R1 is electrically connected to the first end of the leakage current sampling resistor, the second end of the leakage current sampling resistor is electrically connected to the second end of the thermistor, the first end of the filter capacitor C1 is electrically connected to the first end of the current sampling resistor R2, the second end of the filter capacitor C1 is electrically connected to the second end of the current sampling resistor R2, the primary side of the bidirectional optocoupler U1 is connected in parallel with the filter capacitor C1, and the secondary side of the bidirectional optocoupler U1 generates a detection signal. It can be seen that the leakage current detection device has a problem that the leakage current detection device is interfered by electromagnetic radiation during the start-up and operation of the motor, resulting in a momentary large fluctuation in the leakage current value displayed by the detection device, thereby causing the detection stability of the leakage current detection device to decrease. Summary of the invention

[0006] To this end, the present invention provides a leakage current detection device for a cable line, which is used to overcome the problem in the prior art that the leakage current detection device is installed subject to electromagnetic radiation interference during the startup and operation of the motor, resulting in instantaneous large fluctuations in the leakage current value displayed by the detection device, thereby reducing the detection stability of the leakage current detection device.

[0007] To achieve the above-mentioned purpose, the present invention provides a leakage current detection device for a cable line, comprising: a leakage current acquisition module, which is used to detect the leakage current of the cable line through the leakage current detection device, including a leakage current transformer for sampling the leakage current signal, an amplifier connected to the leakage current transformer for amplifying the leakage current signal, a filter connected to the amplifier for filtering the amplified leakage current signal, and a power supply; a detection module, which is connected to the leakage current acquisition module, including a voltage sensor for detecting the working voltage of the leakage current detection device and a temperature sensor for detecting the temperature of the leakage current detection device; an alarm module, which is connected to the leakage current acquisition module, and is used to issue an alarm when the leakage current exceeds a threshold value, including a filter for filtering the amplified leakage current signal. A comparator for comparing the leakage current with the threshold value and an alarm connected to the comparator for issuing an alarm; a communication module connected to the leakage current acquisition module for transmitting the filtered leakage current signal to the display module; the display module connected to the communication module for displaying the filtered leakage current signal; a control module connected to the leakage current acquisition module, the detection module, the alarm module, the communication module and the display module respectively, for determining the sampling frequency of the leakage current according to the variance of the fluctuation amplitude of the leakage current, or determining the cut-off frequency of the filter according to the average working voltage of the leakage current detection device, and determining the output power of the power supply according to the average working voltage of the leakage current detection device and the temperature rise rate of the leakage current detection device.

[0008] Furthermore, the control module is used to determine whether the detection stability of the leakage current detection device meets the requirements based on the variance of the fluctuation amplitude of the leakage current. If the variance of the fluctuation amplitude of the leakage current is greater than a preset first variance, it is determined that the detection stability of the leakage current detection device does not meet the requirements.

[0009] Furthermore, the control module is used to preliminarily determine that the detection reliability of the leakage current detection device does not meet the requirements when the variance of the fluctuation amplitude of the leakage current is greater than the preset first variance and less than or equal to the preset second variance, and determine whether the detection reliability of the leakage current detection device meets the requirements based on the average operating voltage of the leakage current detection device.

[0010] Furthermore, the control module is used to reduce the sampling frequency of the leakage current when the variance of the fluctuation amplitude of the leakage current is greater than the preset second variance; The reduction range of the sampling frequency of the leakage current is determined by the difference between the variance of the fluctuation amplitude of the leakage current and a preset second variance.

[0011] Furthermore, the control module is used to determine whether the detection reliability of the leakage current detection device meets the requirements based on the average working voltage of the leakage current detection device. If the average working voltage of the leakage current detection device is greater than the preset first working voltage, it is determined that the detection reliability of the leakage current detection device does not meet the requirements.

[0012] Furthermore, the control module is used to reduce the cut-off frequency of the filter when the average operating voltage of the leakage current detection device is greater than the preset first operating voltage and less than or equal to a preset second operating voltage.

[0013] Furthermore, the control module is used to preliminarily determine that the environmental stability detected by the leakage current detection device does not meet the requirements when the average operating voltage of the leakage current detection device is greater than the preset second operating voltage, and determine the environmental stability detected by the leakage current detection device according to the temperature rise rate of the leakage current detection device.

[0014] Furthermore, the reduction range of the cut-off frequency of the filter is determined by the difference between the average working voltage of the leakage current detection device and a preset first working voltage.

[0015] Furthermore, the control module is used to determine whether the environmental stability detected by the leakage current detection device meets the requirements based on the temperature rise rate of the leakage current detection device. If the temperature rise rate of the leakage current detection device is greater than the preset rise rate, it is determined that the environmental stability detected by the leakage current detection device does not meet the requirements, and the output power of the power supply is reduced.

[0016] Furthermore, the reduction range of the output power of the power supply is determined by the difference between the temperature increase rate of the leakage current detection device and a preset increase rate.

[0017] Compared with the prior art, the beneficial effect of the present invention is that the device of the present invention determines the sampling frequency of the leakage current according to the variance of the fluctuation amplitude of the leakage current by setting a leakage current acquisition module, a detection module, an alarm module, a communication module, a display module and a control module. Since there are many large motors in the factory for driving production equipment, when the leakage current detection device is installed near the motor control cabinet, the electromagnetic radiation generated during the start-up and operation of the motor will interfere with the detection device, causing the leakage current value displayed by the detection device to fluctuate greatly in an instant. By reducing the sampling frequency of the leakage current, the amount of interference data collected can be reduced, thereby reducing the burden of data processing and improving data processing efficiency. The filter is adjusted according to the average working voltage of the leakage current detection device. The cut-off frequency is determined. After the power supply line is used for a long time, the insulation layer of the wire may age and break, resulting in leakage. The leakage will change the current in the line, which will cause voltage fluctuations. By reducing the cut-off frequency of the filter, the low-frequency interference components can be better filtered out, making the output voltage more stable, thereby alleviating the voltage fluctuations to a certain extent. The output power of the power supply is determined according to the temperature rise rate of the leakage current detection device. As the use time of the electronic components in the detection device increases, their performance will gradually decline, resulting in an increase in internal resistance and more heat. By reducing the output power of the power supply, the components can be operated at a lower power state, reducing heat generation and improving the detection stability of the leakage current detection device.

[0018] Furthermore, the device described in the present invention determines the sampling frequency of the leakage current by setting a preset first variance and a preset second variance. Since there are many large motors in the factory for driving production equipment, when the leakage current detection device is installed near the motor control cabinet, the electromagnetic radiation generated during the startup and operation of the motor will interfere with the detection device, causing the leakage current value displayed by the detection device to show instantaneous large fluctuations. By reducing the sampling frequency of the leakage current, the amount of interference data collected can be reduced, thereby reducing the burden of data processing, improving data processing efficiency, and further improving the detection stability of the leakage current detection device.

[0019] Furthermore, the device described in the present invention determines the cutoff frequency of the filter by setting a preset first working voltage and a preset second working voltage. After the power line is used for a long time, the insulation layer of the wire may age and be damaged, resulting in leakage. The leakage will cause the current in the line to change, and then cause the voltage to fluctuate. By reducing the cutoff frequency of the filter, the low-frequency interference components can be better filtered out, making the output voltage more stable, thereby reducing the voltage fluctuation to a certain extent and further improving the detection stability of the leakage current detection device.

[0020] Furthermore, the device described in the present invention determines the output power of the power supply by setting a preset increase rate. As the use time of the electronic components in the detection device increases, their performance will gradually decline, resulting in an increase in internal resistance and more heat will be generated. By reducing the output power of the power supply, the components can operate in a lower power state, reducing heat generation, and further improving the detection stability of the leakage current detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the overall structure of a leakage current detection device for a cable according to an embodiment of the present invention; Figure 2 This is an overall structural block diagram of a leakage current detection device for a cable according to an embodiment of the present invention; Figure 3 A logic flow chart of a leakage current detection device for a cable according to an embodiment of the present invention; Figure 4 A specific structural block diagram of a leakage current acquisition module of a leakage current detection device for a cable according to an embodiment of the present invention; The reference numerals are as follows: 1 - alarm, 2 - temperature sensor, 3 - amplifier, 4 - leakage current transformer, 5 - filter, 6 - power supply, 7 - voltage sensor, 8 - comparator. DETAILED DESCRIPTION

[0022] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0024] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0025] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] See also Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, they are respectively an overall structural schematic diagram, an overall structural block diagram, a logic flow chart and a specific structural block diagram of a leakage current acquisition module of a leakage current detection device for a cable line according to an embodiment of the present invention. A leakage current detection device for a cable line according to the present invention comprises: A leakage current acquisition module, used to detect the leakage current of the cable through a leakage current detection device, including a leakage current transformer 4 for sampling the leakage current signal, an amplifier 3 connected to the leakage current transformer 4 for amplifying the leakage current signal, a filter 5 connected to the amplifier 3 for filtering the amplified leakage current signal, and a power supply 6; A detection module, which is connected to the leakage current acquisition module, and includes a voltage sensor 7 for detecting the working voltage of the leakage current detection device and a temperature sensor 2 for detecting the temperature of the leakage current detection device; An alarm module, which is connected to the leakage current acquisition module and is used to issue an alarm when the leakage current exceeds a threshold value, comprising a comparator 8 for comparing the leakage current with the threshold value and an alarm 1 connected to the comparator 8 for issuing an alarm; A communication module, connected to the leakage current acquisition module, for transmitting the filtered leakage current signal to the display module; The display module is connected to the communication module and is used to display the filtered leakage current signal; A control module, which is respectively connected to the leakage current acquisition module, the detection module, the alarm module, the communication module and the display module, and is used to determine the sampling frequency of the leakage current according to the variance of the fluctuation amplitude of the leakage current, or to determine the cutoff frequency of the filter 5 according to the average working voltage of the leakage current detection device, and to determine the output power of the power supply 6 according to the average working voltage of the leakage current detection device and the temperature rise rate of the leakage current detection device.

[0027] Specifically, the amplifier 3 is an instrumentation amplifier, an operational amplifier, or a power amplifier.

[0028] Specifically, the filter 5 is a low-pass filter, a high-pass filter, or a band-pass filter, and a preferred embodiment thereof is a low-pass filter.

[0029] Specifically, the display module is a display screen.

[0030] In practice, the device of the present invention determines the sampling frequency of the leakage current according to the variance of the fluctuation amplitude of the leakage current by setting a leakage current acquisition module, a detection module, an alarm module, a communication module, a display module and a control module. Since there are many large motors in the factory for driving production equipment, when the leakage current detection device is installed near the motor control cabinet, the electromagnetic radiation generated during the start-up and operation of the motor will interfere with the detection device, causing the leakage current value displayed by the detection device to fluctuate greatly in an instant. By reducing the sampling frequency of the leakage current, the amount of interference data collected can be reduced, thereby reducing the burden of data processing and improving data processing efficiency. The cutoff frequency of the filter 5 is determined according to the average working voltage of the leakage current detection device. It is determined that after long-term use of the power supply 6 line, the insulation layer of the wire may age and break, resulting in leakage. The leakage will cause the current in the line to change, which in turn causes voltage fluctuations. By reducing the cut-off frequency of the filter 5, the low-frequency interference components can be better filtered out, making the output voltage more stable, thereby alleviating the voltage fluctuations to a certain extent. The output power of the power supply 6 is determined according to the temperature rise rate of the leakage current detection device. As the use time of the electronic components in the detection device increases, their performance will gradually decline, resulting in an increase in internal resistance and more heat. By reducing the output power of the power supply 6, the components can be operated at a lower power state, reducing heat generation and improving the detection stability of the leakage current detection device.

[0031] Specifically, the control module is used to obtain the magnitude of the leakage current within several detection cycles and calculate the variance of the fluctuation amplitude of the leakage current. If the variance of the fluctuation amplitude of the leakage current is greater than a preset first variance, it is determined that the detection stability of the leakage current detection device does not meet the requirements.

[0032] Specifically, the control module is used to preliminarily determine that the detection reliability of the leakage current detection device does not meet the requirements when the variance of the fluctuation amplitude of the leakage current is greater than the preset first variance and less than or equal to the preset second variance, and determine whether the detection reliability of the leakage current detection device meets the requirements based on the average operating voltage of the leakage current detection device.

[0033] It can be understood that the three intervals corresponding to the preset first variance and the preset second variance correspond to three situations respectively: The first interval is when the variance of the fluctuation amplitude of the leakage current is less than or equal to the preset first variance, corresponding to the situation where the detection stability of the leakage current detection device meets the requirements; The second interval is when the variance of the fluctuation amplitude of the leakage current is greater than the preset first variance and less than or equal to the preset second variance. After the power supply line 6 is used for a long time, the insulation layer of the wire may age and break, resulting in leakage. The leakage will cause the current in the line to change, thereby causing the voltage to fluctuate. The third interval is when the variance of the leakage current fluctuation amplitude is greater than the preset second variance. There are many large motors in the corresponding factory used to drive production equipment. When the leakage current detection device is installed near the motor control cabinet, the electromagnetic radiation generated during the startup and operation of the motor will interfere with the detection device, causing the leakage current value displayed by the detection device to fluctuate greatly in an instant.

[0034] In practice, the preset first variance is generally selected in the range of [8 (mA) 2 , 12 (mA) 2 ], the preset second variance is generally selected in the range of [13 (mA) 2 , 17 (mA) 2 ].

[0035] Preferably, the preferred embodiment of the preset first variance is 10 (mA) 2 , the preferred embodiment of the preset second variance is 15 (mA) 2 .

[0036] Specifically, the variance of the fluctuation amplitude of the leakage current is the variance of the fluctuation amplitude of the leakage current within several detection cycles. The calculation method of the variance of the fluctuation amplitude of the leakage current is a conventional technical means well known to technical personnel in this field, so the calculation process of the variance of the fluctuation amplitude of the leakage current will not be repeated here.

[0037] In implementation, the device described in the present invention determines the detection stability of the leakage current detection device by setting a preset first variance and a preset second variance, thereby reducing the impact of the decrease in detection accuracy of the leakage current detection device due to inaccurate determination of the detection stability of the leakage current detection device, and further improving the detection stability of the leakage current detection device.

[0038] Specifically, the control module is used to reduce the sampling frequency of the leakage current when the variance of the fluctuation amplitude of the leakage current is greater than the preset second variance; The reduction range of the sampling frequency of the leakage current is determined by the difference between the variance of the fluctuation amplitude of the leakage current and a preset second variance.

[0039] Specifically, the difference between the fluctuation amplitude variance of the leakage current and the preset second variance is 3 (mA) 2 When the difference between the fluctuation amplitude of the leakage current and the preset second variance exceeds 3 (mA), the sampling frequency of the leakage current is reduced to 0.95 times of the original value.2 When the current exceeds 1 (mA) 2 , the sampling frequency of the leakage current is reduced by 5Hz. For example, the difference between the variance of the fluctuation amplitude of the leakage current and the preset second variance is 5 (mA) 2 , the sampling frequency of the current leakage current is 60Hz, and the sampling frequency of the reduced leakage current is 60×0.95-5×2=47Hz.

[0040] In implementation, the device of the present invention determines the sampling frequency of the leakage current by setting a preset first variance and a preset second variance. Since there are many large motors in the factory for driving production equipment, when the leakage current detection device is installed near the motor control cabinet, the electromagnetic radiation generated during the startup and operation of the motor will interfere with the detection device, causing the leakage current value displayed by the detection device to fluctuate greatly in an instant. By reducing the sampling frequency of the leakage current, the amount of interference data collected can be reduced, thereby reducing the burden of data processing, improving data processing efficiency, and further improving the detection stability of the leakage current detection device.

[0041] Specifically, the control module is used to obtain the working voltage of the leakage current detection device within several detection cycles and calculate the average working voltage of the leakage current detection device. If the average working voltage of the leakage current detection device is greater than the preset first working voltage, it is determined that the detection reliability of the leakage current detection device does not meet the requirements.

[0042] Specifically, the control module is used to reduce the cutoff frequency of the filter 5 when the average operating voltage of the leakage current detection device is greater than the preset first operating voltage and less than or equal to the preset second operating voltage.

[0043] Specifically, the control module is used to preliminarily determine that the environmental stability detected by the leakage current detection device does not meet the requirements when the average operating voltage of the leakage current detection device is greater than the preset second operating voltage, and to determine the environmental stability detected by the leakage current detection device according to the temperature rise rate of the leakage current detection device.

[0044] It can be understood that the three intervals corresponding to the preset first operating voltage and the preset second operating voltage correspond to three situations respectively: The first interval is when the average working voltage of the leakage current detection device is less than or equal to the preset first working voltage, corresponding to the situation where the detection reliability of the leakage current detection device meets the requirements; The second interval is when the average working voltage of the leakage current detection device is greater than the preset first working voltage and less than or equal to the preset second working voltage. After the power supply line 6 is used for a long time, the insulation layer of the wire may age and break, resulting in leakage. The leakage will cause the current in the line to change, thereby causing the voltage to fluctuate. The third interval is when the average operating voltage of the leakage current detection device is greater than the preset second operating voltage, which corresponds to the situation where as the use time of the electronic components in the detection device increases, their performance will gradually decline, resulting in increased internal resistance and more heat generation.

[0045] In practice, the preset first operating voltage is generally selected from a range of [4.3V, 4.7V], and the preset second operating voltage is generally selected from a range of [4.8V, 5.2V].

[0046] Preferably, the preferred embodiment of the preset first operating voltage is 4.5V, and the preferred embodiment of the preset second operating voltage is 5V.

[0047] Specifically, the average operating voltage of the leakage current detection device is the ratio of the total operating voltage of the leakage current detection device in a number of detection cycles to the number of detection cycles.

[0048] In implementation, the device described in the present invention determines the detection reliability of the leakage current detection device by setting a preset first operating voltage and a preset second operating voltage, thereby reducing the impact of the decreased detection stability of the leakage current detection device due to inaccurate determination of the detection reliability of the leakage current detection device, and further improving the detection stability of the leakage current detection device.

[0049] Specifically, the reduction range of the cut-off frequency of the filter 5 is determined by the difference between the average working voltage of the leakage current detection device and the preset first working voltage.

[0050] Specifically, when the difference between the average working voltage of the leakage current detection device and the preset first working voltage is within 1V, the cutoff frequency of the filter 5 is reduced to 0.92 times the original value; when the difference between the average working voltage of the leakage current detection device and the preset first working voltage exceeds 1V, the cutoff frequency of the filter 5 is reduced by 5Hz for every 0.5V exceeding. For example, the difference between the average working voltage of the leakage current detection device and the preset first working voltage is 2V, the current cutoff frequency of the filter 5 is 50Hz, and the reduced cutoff frequency of the filter 5 is 50×0.92-5×2=36Hz.

[0051] In implementation, the device of the present invention determines the cutoff frequency of the filter 5 by setting a preset first working voltage and a preset second working voltage. After the power supply 6 line is used for a long time, the insulation layer of the wire may age and be damaged, resulting in leakage. The leakage will cause the current in the line to change, and then cause the voltage to fluctuate. By reducing the cutoff frequency of the filter 5, the low-frequency interference components can be better filtered out, making the output voltage more stable, thereby reducing the voltage fluctuation to a certain extent and further improving the detection stability of the leakage current detection device.

[0052] Specifically, the control module is used to obtain the temperature of the leakage current detection device at the initial moment of a single cycle and the temperature of the leakage current detection device at the end moment of a single cycle, and calculate the temperature rise rate of the leakage current detection device. If the temperature rise rate of the leakage current detection device is greater than the preset rise rate, it is determined that the environmental stability detected by the leakage current detection device does not meet the requirements, and the output power of the power supply 6 is reduced.

[0053] It can be understood that the two intervals corresponding to the preset increase rate correspond to two situations: The first interval is when the temperature increase rate of the leakage current detection device is less than or equal to the preset increase rate, corresponding to the situation where the environmental stability detected by the leakage current detection device meets the requirements; The second interval is when the temperature rise rate of the leakage current detection device is greater than the preset rise rate, which corresponds to the situation where as the use time of the electronic components in the detection device increases, their performance will gradually decline, resulting in increased internal resistance and more heat generation.

[0054] In practice, the preset temperature increase rate is generally selected in the range of [2°C / min, 4°C / min].

[0055] Preferably, the preset increasing rate is preferably 3° C. / min.

[0056] Specifically, the temperature increase rate of the leakage current detection device is the ratio of the difference between the temperature of the leakage current detection device at the end of a single cycle and the temperature of the leakage current detection device at the beginning of a single cycle to the duration of the single cycle.

[0057] In implementation, the device described in the present invention determines the environmental stability detected by the leakage current detection device by setting a preset increase rate, thereby reducing the impact of the decreased detection stability of the leakage current detection device due to inaccurate determination of the environmental stability detected by the leakage current detection device, and further improving the detection stability of the leakage current detection device.

[0058] Specifically, the reduction range of the output power of the power supply 6 is determined by the difference between the temperature increase rate of the leakage current detection device and the preset increase rate.

[0059] Specifically, when the difference between the temperature rise rate of the leakage current detection device and the preset temperature rise rate is within 2°C / min, the output power of the power supply 6 is reduced to 0.9 times the original value; when the difference between the temperature rise rate of the leakage current detection device and the preset temperature rise rate exceeds 2°C / min, the output power of the power supply 6 is reduced by 0.5mW for every 0.5°C / min exceeding the preset temperature rise rate. For example, the difference between the temperature rise rate of the leakage current detection device and the preset temperature rise rate is 3°C / min, the current output power of the power supply 6 is 10mW, and the reduced output power of the power supply 6 is 10×0.9-0.5×2=8mW.

[0060] In implementation, the device described in the present invention determines the output power of the power supply 6 by setting a preset increase rate. As the use time of the electronic components in the detection device increases, their performance will gradually decline, resulting in an increase in internal resistance and more heat will be generated. By reducing the output power of the power supply 6, the components can operate in a lower power state, reducing heat generation, and further improving the detection stability of the leakage current detection device.

[0061] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A leakage current detection device for a cable, characterized in that: include: A leakage current acquisition module, used to detect the leakage current of the cable through a leakage current detection device, including a leakage current transformer for sampling the leakage current signal, an amplifier connected to the leakage current transformer for amplifying the leakage current signal, a filter connected to the amplifier for filtering the amplified leakage current signal, and a power supply; A detection module, which is connected to the leakage current acquisition module and includes a voltage sensor for detecting the working voltage of the leakage current detection device and a temperature sensor for detecting the temperature of the leakage current detection device; An alarm module, which is connected to the leakage current acquisition module and is used to issue an alarm when the leakage current exceeds a threshold value, comprising a comparator for comparing the leakage current with the threshold value and an alarm connected to the comparator for issuing an alarm; A communication module, connected to the leakage current acquisition module, for transmitting the filtered leakage current signal to the display module; The display module is connected to the communication module and is used to display the filtered leakage current signal; A control module, which is respectively connected to the leakage current acquisition module, the detection module, the alarm module, the communication module and the display module, and is used to determine the sampling frequency of the leakage current according to the variance of the fluctuation amplitude of the leakage current, or to determine the cut-off frequency of the filter according to the average working voltage of the leakage current detection device, and to determine the output power of the power supply according to the average working voltage of the leakage current detection device and the temperature rise rate of the leakage current detection device.

2. The leakage current detection device for a cable according to claim 1, characterized in that: The control module is used to determine whether the detection stability of the leakage current detection device meets the requirements according to the variance of the fluctuation amplitude of the leakage current. If the variance of the fluctuation amplitude of the leakage current is greater than a preset first variance, it is determined that the detection stability of the leakage current detection device does not meet the requirements.

3. The leakage current detection device for a cable according to claim 2, characterized in that: The control module is used to preliminarily determine that the detection reliability of the leakage current detection device does not meet the requirements when the variance of the fluctuation amplitude of the leakage current is greater than the preset first variance and less than or equal to the preset second variance, and to determine whether the detection reliability of the leakage current detection device meets the requirements based on the average operating voltage of the leakage current detection device.

4. The leakage current detection device for a cable according to claim 3, characterized in that: The control module is used for reducing the sampling frequency of the leakage current when the variance of the fluctuation amplitude of the leakage current is greater than the preset second variance; The reduction range of the sampling frequency of the leakage current is determined by the difference between the variance of the fluctuation amplitude of the leakage current and a preset second variance.

5. The leakage current detection device for a cable according to claim 3, characterized in that: The control module is used to determine whether the detection reliability of the leakage current detection device meets the requirements based on the average working voltage of the leakage current detection device. If the average working voltage of the leakage current detection device is greater than the preset first working voltage, it is determined that the detection reliability of the leakage current detection device does not meet the requirements.

6. The leakage current detection device for a cable according to claim 5, characterized in that: The control module is used to reduce the cut-off frequency of the filter when the average operating voltage of the leakage current detection device is greater than the preset first operating voltage and less than or equal to the preset second operating voltage.

7. The leakage current detection device for a cable according to claim 6, characterized in that: The control module is used to preliminarily determine that the environmental stability detected by the leakage current detection device does not meet the requirements when the average operating voltage of the leakage current detection device is greater than the preset second operating voltage, and determine the environmental stability detected by the leakage current detection device according to the temperature rise rate of the leakage current detection device.

8. The leakage current detection device for a cable according to claim 7, characterized in that: The reduction range of the cut-off frequency of the filter is determined by the difference between the average working voltage of the leakage current detection device and the preset first working voltage.

9. The leakage current detection device for a cable according to claim 8, characterized in that: The control module is used to determine whether the environmental stability detected by the leakage current detection device meets the requirements based on the temperature rise rate of the leakage current detection device. If the temperature rise rate of the leakage current detection device is greater than the preset rise rate, it is determined that the environmental stability detected by the leakage current detection device does not meet the requirements, and the output power of the power supply is reduced.

10. The leakage current detection device for a cable according to claim 9, characterized in that: The reduction range of the output power of the power supply is determined by the difference between the temperature increase rate of the leakage current detection device and a preset increase rate.

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