A portable device for detecting leakage current in a power distribution area

Abstract

The application belongs to the field of transformer area electric leakage detection, and specifically discloses a portable transformer area electric leakage detection device, which comprises a shell and an electric leakage analyzer, two horizontal frames are arranged in parallel inside the shell, a plurality of clamping wheels are symmetrically arranged on the two horizontal frames, a rotary driver is arranged on the horizontal frame and is used for driving the clamping wheels to move, a clamping driver connected with the horizontal frame is arranged in the machine box at the rear side of the shell, a current transformer is further arranged in the shell, a power supply module and the electric leakage analyzer are arranged in the machine box, an electric contact is further arranged on the horizontal frame, the electric contact is in abutment with a cable and is electrically connected with the electric leakage analyzer. The device has the characteristics of convenient installation, accurate positioning and strong adaptability, can effectively solve the problems of inconvenient installation and inaccurate positioning of the existing detection device, and can effectively improve the efficiency and reliability of transformer area electric leakage detection, reduce operation and maintenance cost, and ensure the safe and stable operation of the low-voltage distribution network.

Description

Technical Field

[0001] This invention belongs to the field of transformer substation leakage current detection, and specifically relates to a portable transformer substation leakage current detection device. Background Technology

[0002] As the final link in the distribution network, low-voltage transformer substations directly connect to various electrical terminals. Their cables are widely distributed and have numerous nodes. Due to geographical limitations and the age of the lines, some substations are prone to problems such as aging and damaged cable insulation, poor insulation at joints, and unauthorized wiring, leading to leakage faults. Leakage faults not only cause energy loss but also easily induce electrical fires, electric shocks, and other safety accidents. They can also cause frequent tripping of residual current circuit breakers (RCCBs) in the substation, affecting power supply reliability, leading to power quality complaints, and causing significant challenges to power supply operation and maintenance. Therefore, leakage detection and accurate fault location in transformer substations are crucial for ensuring the safe operation of low-voltage distribution networks and are one of the core requirements of power supply operation and maintenance.

[0003] Portable leakage current detection devices have become a primary tool for on-site maintenance and troubleshooting due to their advantages of mobility and wide adaptability. However, existing portable transformer substation leakage current detection devices still have many shortcomings in practical applications, making it difficult to meet the needs of efficient and accurate maintenance. The most prominent problems are concentrated in the areas of ease of installation and positioning accuracy. Regarding ease of installation, existing portable devices mostly require connection to the cable under test via test leads and clamps. The installation process often requires power outages, which is not only cumbersome and time-consuming but may also affect normal power supply. At the same time, the installation structure of existing devices has poor adaptability, making it difficult to flexibly adapt to main lines, branch lines, and service connections of different diameters in transformer substations. The installation difficulty is even greater in complex scenarios such as high-altitude cables and dense cables, making rapid deployment and detection impossible. Regarding the accuracy of leakage point location, existing devices are significantly affected by the complex structure of the distribution network in the transformer substation, numerous branches, stray capacitance interference, and the compensation effect of the arc suppression coil. The leakage characteristic signal is weak and prone to signal aliasing, making it difficult to accurately extract effective fault information. The location error is relatively large, often requiring maintenance personnel to make multiple trips to the site and check section by section, which significantly increases the workload of maintenance and fault handling time. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention aims to provide a portable transformer substation leakage current detection device. This device features convenient installation, accurate positioning, and strong adaptability, effectively solving the problems of inconvenient installation and inaccurate positioning of existing detection devices. This portable transformer substation leakage current detection device can effectively improve the efficiency and reliability of transformer substation leakage current detection, reduce operation and maintenance costs, and ensure the safe and stable operation of low-voltage distribution networks.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A portable transformer substation leakage current detection device includes a housing and a leakage current analyzer. The housing has a U-shaped design with the opening facing forward. An upper and lower crossbeam are arranged parallel to each other inside the housing. Both crossbeams are vertically slidably mounted on the inner wall of the housing. Multiple sets of clamping wheels are symmetrically mounted on the two crossbeams. A cable passes horizontally through the middle of the housing and is clamped between the corresponding upper and lower clamping wheels. A rotary actuator for driving the clamping wheels is mounted on the lower crossbeam. A housing is fixed to the rear side of the housing. The clamping actuator is installed inside the housing, and its actuating part passes through the side wall of the housing and is connected to the two crossbeams. A current transformer is also installed inside the housing. A power supply module and the leakage current analyzer are installed inside the housing. Electrical contacts are symmetrically mounted on the upper and lower crossbeams, respectively. The electrical contacts abut against the cable and are electrically connected to the leakage current analyzer. A warning light is installed on the outer wall of the housing. The current transformer and the warning light are both electrically connected to the leakage current analyzer.

[0006] Furthermore, the leakage current analyzer includes a main control module, a signal filtering module, a current signal acquisition module, a leakage current fault location module, a voltage synchronization acquisition module, a local data storage module, and a wireless communication module; The main control module is used to analyze and process the received current and voltage signals and output relevant control electrical signals. The signal filtering module combines hardware filtering with digital filtering algorithms to filter out high-frequency interference, power frequency harmonics and random noise, and purify the real residual leakage current signal. The current signal acquisition module is used to acquire the leakage current signal of the transformer area line in real time. The leakage fault location module is integrated inside the leakage analyzer and used in conjunction with an external pulse signal transmitting unit. After a leakage fault is detected, it injects a detection pulse signal of a specific frequency into the transformer area line, and combines the transmission attenuation and reflection characteristics of the pulse signal to analyze and calculate the location of the leakage fault point, thereby achieving accurate location of the leakage fault. The voltage synchronization acquisition module is electrically connected to the transformer area line through the electrical contact; it is used to synchronously acquire the phase voltage and line voltage signals of the transformer area line. The local data storage module is electrically connected to the storage control interface of the main control module and is expanded using built-in flash memory and external storage cards. It is used to automatically store historical detection data, including detection time, detection area number, leakage current value, voltage value, fault type, and location information. It supports local query, export, and deletion of data. The storage capacity is expandable to meet the data retention requirements of long-term and multiple detection areas. The wireless communication module is electrically connected to the communication interface of the main control module and is integrated inside the device to realize wireless data transmission with the power grid operation and maintenance management platform.

[0007] Furthermore, a front baffle is hinged to the front opening of the housing, and the front baffle is fixedly connected to the housing by a locking structure.

[0008] Furthermore, a counterweight is installed on the front baffle.

[0009] Furthermore, the clamping driver includes a motor, a screw, a moving rod, and two sets of connecting rod assemblies. A notch is provided through the rear side wall of the housing, and the two connecting rod assemblies are respectively connected to the corresponding crossbeams through the notch. The moving rod is vertically movably disposed inside the housing. The connecting rod assembly includes a longitudinal sliding block, a first connecting rod, a second connecting rod, and a sliding sleeve. One end of the longitudinal sliding block is fixed to the corresponding crossbeam, and the other end is movably inserted through the notch into the housing and rotatably connected to one end of the first connecting rod. The other end of the first connecting rod is tilted upward and rotatably connected to the sliding sleeve, which is slidably sleeved on the moving rod. One end of the second connecting rod is rotatably connected to the sliding sleeve, and the other end is tilted upward and rotatably connected to the inner wall of the housing, with the two connecting rods tilted in opposite directions. The screw is horizontally disposed inside the housing and is poweredly connected to the output shaft of the motor outside the housing. The middle part of the moving rod is threaded onto the screw.

[0010] Furthermore, a slide rail is vertically installed on the inner wall of the housing, and two crossbars are vertically slidably installed on the slide rail.

[0011] Furthermore, an insulating rod is horizontally fixed to the side of the electrical contact near the corresponding crossbeam. The corresponding crossbeam has a cavity inside, and a sliding rod is vertically fixed inside the cavity. The insulating rod extends into the cavity through a strip hole opened on the corresponding crossbeam. A vertical hole is opened through the insulating rod, and the insulating rod is slidably sleeved on the sliding rod through the vertical hole. A spring is sleeved on the sliding rod, and the spring is located on the sliding rod away from the cable and abuts against the insulating rod.

[0012] Furthermore, the end of the electrical contact near the cable is provided with an arc-shaped notch that matches the shape of the cable's outer wall.

[0013] The beneficial effects of this invention are as follows: 1. When using this application, after the cable is installed in place, the front baffle on the front side is flipped closed and locked by the latch structure. Since the box is installed on the rear side of the housing, the counterweight balance block on the front side can play an effective counterweight balance role.

[0014] 2. When the screw is rotated by the motor, the moving rod can be driven to move horizontally to the side of the housing. The two upper and lower second connecting rods rotate and swing around the rotating connection point, thereby causing the corresponding sliding sleeve to slide along the moving rod towards the middle. The corresponding first connecting rod pushes the two longitudinal blocks to move closer to the middle, thereby causing the upper and lower cross frames inside the housing to move the clamping wheels on them closer to each other. The clamping wheels, which are symmetrically arranged, clamp the cable that crosses the middle of the housing from top to bottom, realizing the rapid fixing and clamping of the cable. The arc groove on the clamping wheel can adapt to the clamping and fixing of different types of cables.

[0015] 3. When the two crossbars of this application approach each other, they will cause the upper and lower electrical contacts to approach and abut against the cable. As the two crossbars continue to approach each other, under the action of the spring force, the electrical contacts will be driven by the insulating rod to stably abut against the cable, so that this device can be adapted to the contact conduction of cables of different diameters and models.

[0016] 4. The main control module of this application can perform comprehensive analysis by combining leakage current data to determine whether leakage fault is related to line overvoltage, undervoltage, or voltage imbalance. At the same time, it monitors whether the power supply voltage of the transformer area meets the standard, realizing integrated detection of "leakage + voltage" and comprehensively grasping the electrical operating status of the transformer area lines. Attached Figure Description

[0017] Fig. 1 This is a schematic diagram of the structure of the present invention; Fig. 2 This is a schematic diagram of the installation of the clamping driver of the present invention; Fig. 3 This is a schematic diagram of the installation of the electrical contact of the present invention. Detailed Implementation

[0018] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention.

[0019] like Figs. 1-3 As shown, this invention proposes a portable transformer substation leakage current detection device, including a housing 1 and a leakage current analyzer 9. The housing 1 has a U-shaped design with the opening facing forward, and the cable 7 passes through the left and right sides of the housing 1. A front baffle 12 is hinged to the front opening of the housing 1, and the front baffle 12 is fixed to the housing 1 by a locking structure; a counterweight 121 is installed on the front baffle 12.

[0020] When this application is used, after the cable 7 is installed in place, the front baffle 12 on the front side is flipped to close and locked by the locking structure. Since the box is installed on the rear side of the housing 1, the counterweight balance block 121 on the front side can play an effective counterweight balance role.

[0021] The housing 1 has an upper horizontal frame 21 and a lower horizontal frame 22 arranged vertically and parallel to each other inside, both of which are vertically slidably mounted on the inner wall of the housing 1. Specifically, a slide rail 11 is vertically mounted on the inner side wall of the housing 1, and the two horizontal frames are vertically slidably mounted on the slide rail 11. The sliding mounting of the upper horizontal frame 21 and the lower horizontal frame 22 on the slide rail 11 can significantly improve the stability of the two horizontal frames when moving vertically. Multiple sets of clamping wheels 3 are symmetrically mounted on the two horizontal frames, and the cable 7 passes horizontally through the middle of the housing 1 and is clamped between the two corresponding clamping wheels 3. The lower horizontal frame 22 is provided with a rotary driver 31 that drives the clamping wheels 3 to move. The rotary driver 31 can adopt a drive motor structure commonly used in the prior art. The drive motor can provide power to the clamping wheels 3 on the lower horizontal frame 22. The clamping wheels 3 on the lower horizontal frame 22 are the driving wheels, and the clamping wheels 3 on the upper horizontal frame 21 are the driven wheels. Under the clamping of the upper and lower clamping wheels 3, the device is driven to move on the cable 7.

[0022] A housing 1 is fixedly mounted on its rear side, and a clamping driver is installed inside the housing. The actuating part of the clamping driver penetrates the side wall of the housing 1 and is connected to two crossbeams. Specifically, the clamping driver includes a motor 87, a screw 86, a moving rod 85, and two sets of vertically symmetrically arranged linkage assemblies. A notch 10 is provided through the rear side wall of the housing 1, and the two linkage assemblies penetrate the notch 10 and are respectively connected to the corresponding crossbeams. The moving rod 85 is vertically movable inside the housing. The linkage assembly includes a longitudinal moving block 81, a first connecting rod 82, a second connecting rod 83, and a sliding sleeve 84. One end of the longitudinal moving block 81 is fixed to the corresponding crossbeam, and the other end movably extends through the notch 10. The first connecting rod 83 is inserted into the housing and rotatably connected to one end of the first connecting rod 82. The other end of the first connecting rod 82 is rotatably connected to the sliding sleeve 84 at an upward tilt. The sliding sleeve 84 is slidably fitted onto the moving rod 85. One end of the second connecting rod 83 is rotatably connected to the sliding sleeve 84, and the other end is rotatably connected to the inner wall of the housing at an upward tilt. The two connecting rods are tilted in opposite directions. The screw 86 is horizontally installed inside the housing and is poweredly connected to the output shaft of the motor 87 outside the housing. The middle part of the moving rod 85 is threaded onto the screw 86.

[0023] When the screw 86 is rotated by the motor 87, the moving rod 85 can be driven to move horizontally to the side of the housing 1. The two upper and lower second connecting rods 83 rotate and swing around the rotating connection, thereby causing the corresponding sliding sleeve 84 to slide along the moving rod 85 towards the middle. The corresponding first connecting rod 82 pushes the two longitudinal blocks 81 to move closer to the middle, thereby causing the upper crossbeam 21 and lower crossbeam 22 inside the housing 1 to drive the clamping wheels 3 on them to move closer to each other. The clamping wheels 3, which are symmetrically arranged, clamp the cable 7 that passes through the middle of the housing 1 from top to bottom, realizing the rapid fixing and clamping of the cable 7. The arc groove on the clamping wheel 3 can adapt to the clamping and fixing of different types of cables 7.

[0024] A current transformer 5 is also installed inside the housing 1. The power supply module and leakage current analyzer 9 are installed inside the housing. Electrical contacts 4 are symmetrically installed on the upper crossbeam 21 and the lower crossbeam 22, respectively. The electrical contacts 4 abut against the cable 7 and are electrically connected to the leakage current analyzer 9. An insulating rod is horizontally fixed to the side of the electrical contact 4 near the corresponding crossbeam. The corresponding crossbeam has a cavity inside, and a sliding rod 42 is vertically fixed in the cavity. The insulating rod extends into the cavity through a strip hole 20 opened on the corresponding crossbeam. A vertical hole is opened through the insulating rod, and the insulating rod slides on the sliding rod 42 through the vertical hole. A spring 421 is fitted on the sliding rod 42. The spring 421 is located on the side of the sliding rod 42 away from the cable 7 and abuts against the insulating rod. The end of the electrical contact 4 near the cable 7 has an arc-shaped notch that matches the shape of the outer wall of the cable 7.

[0025] When the two crossbars of this application approach each other, they will cause the upper and lower electrical contacts 4 to approach and abut against the cable 7. As the two crossbars continue to approach each other, under the elastic force of the spring 421, the electrical contacts 4 will be driven by the insulating rod to stably abut against the cable 7, so that this device can be adapted to the contact conduction of cables 7 of different diameters and models.

[0026] A warning light 6 is installed on the outer wall of the housing 1. Both the current transformer 5 and the warning light 6 are electrically connected to the leakage current analyzer 9. When a leakage current is detected in the cable 7, the leakage current analyzer 9 sends an electrical signal to the warning light 6, illuminating the light and providing information to the operator for timely marking and location. The leakage current analyzer 9 includes a main control module, a signal filtering module, a current signal acquisition module, a leakage fault location module, a voltage synchronization acquisition module, a local data storage module, and a wireless communication module.

[0027] The main control module analyzes and processes the received current and voltage signals and outputs relevant control electrical signals. The signal filtering module combines hardware filtering with digital filtering algorithms to filter out high-frequency interference, power frequency harmonics, and random noise, purifying the true residual leakage current signal. This avoids data distortion and false alarms caused by interference, significantly improving the accuracy and anti-interference capability of leakage detection, and adapting to the complex electromagnetic environment of the transformer substation.

[0028] The current signal acquisition module is used to acquire leakage current signals of transformer substation lines in real time.

[0029] The leakage fault location module is integrated inside the leakage analyzer 9 and used in conjunction with an external pulse signal transmitting unit. After detecting a leakage fault, it injects a detection pulse signal of a specific frequency into the transformer area line. Combining the transmission attenuation and reflection characteristics of the pulse signal, it analyzes and calculates the location of the leakage fault point, achieving accurate location of the leakage fault. This replaces the traditional manual segment-by-segment inspection method, shortens the fault inspection time, and is especially suitable for finding leakage faults in concealed lines and long-distance transformer area lines.

[0030] The voltage synchronization acquisition module is electrically connected to the transformer substation lines via electrical contact 4. It is used to synchronously acquire the phase voltage and line voltage signals of the transformer substation lines. The main control module combines the leakage current data for comprehensive analysis to determine whether the leakage fault is related to overvoltage, undervoltage, or voltage imbalance of the lines. At the same time, it monitors whether the power supply voltage of the transformer substation meets the standard, realizing integrated detection of "leakage current + voltage" to fully understand the electrical operating status of the transformer substation lines.

[0031] The local data storage module is electrically connected to the storage control interface of the main control module, and is expanded using built-in flash memory and external storage cards. It is used to automatically store historical detection data, including detection time, detection area number, leakage current value, voltage value, fault type, and location information. It supports local query, export, and deletion of data. The storage capacity is expandable to meet the data retention needs of long-term and multiple detection areas, providing raw data support for fault analysis and maintenance report generation, and realizing traceability of the detection process.

[0032] The wireless communication module, electrically connected to the communication interface of the main control module, is integrated inside the device and is used to realize wireless data transmission with the power grid operation and maintenance management platform.

[0033] It can integrate one or more of the following modules as needed: Bluetooth module, Wi-Fi module, LoRa module, and 4G / 5G cellular communication module: Bluetooth / Wi-Fi module: enables short-range wireless connection with mobile phones, tablets, and laptops on site, transmitting test data to mobile terminals in real time for easy on-site data viewing, sharing, and preliminary analysis; LoRa module: suitable for long-range low-power data transmission in remote transformer areas, enabling centralized uploading of test data from multiple transformer areas; 4G / 5G module: uploads test data and fault information to the power grid operation and maintenance management platform in real time, enabling remote monitoring and fault alarms. Maintenance personnel can remotely monitor the leakage status of transformer areas and promptly dispatch maintenance personnel to handle faults.

[0034] When using this invention, the front baffle 12 is opened so that the cable 7 passes horizontally through the housing 1 and the current transformer 5. The clamping driver is then activated, causing the upper crossbar 21 and the lower crossbar 22 to move closer to each other, which in turn drives the corresponding clamping wheels 3 to clamp the cable 7. The two electrical contacts 4 then come into contact with the cable 7. After that, the front baffle 12 is closed to lock the locking structure. The rotating driver 31 provides power for the movement of the clamping wheels 3, allowing the device to move along the cable 7. During this process, the main control module, signal filtering module, current signal acquisition module, leakage fault location module, and other functional modules integrated within the device work together to accurately locate and warn of leakage points in the cable 7.

[0035] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. A portable transformer substation leakage current detection device, comprising a housing and a leakage current analyzer, characterized in that: The housing is a U-shaped design with the opening facing forward. Inside the housing, there are two parallel upper and lower crossbars, both vertically sliding on the inner wall of the housing. Multiple sets of clamping wheels are symmetrically mounted on the two crossbars. The cable passes horizontally through the middle of the housing and is clamped between the corresponding upper and lower clamping wheels. A rotary actuator is mounted on the lower crossbar to drive the clamping wheels. A housing is fixed to the rear side of the housing. The clamping actuator is installed inside the housing, and its actuating part passes through the side wall of the housing and is connected to the two crossbars. A current transformer is also installed inside the housing, along with the power supply module and the leakage current analyzer. Electrical contacts are symmetrically mounted on the upper and lower crossbars, respectively. These contacts abut against the cable and are electrically connected to the leakage current analyzer. A warning light is mounted on the outer wall of the housing, and both the current transformer and the warning light are electrically connected to the leakage current analyzer.

2. The portable transformer substation leakage current detection device according to claim 1, characterized in that: The leakage current analyzer includes a main control module, a signal filtering module, a current signal acquisition module, a leakage current fault location module, a voltage synchronization acquisition module, a local data storage module, and a wireless communication module. The main control module is used to analyze and process the received current and voltage signals and output relevant control electrical signals. The signal filtering module combines hardware filtering with digital filtering algorithms to filter out high-frequency interference, power frequency harmonics and random noise, and purify the real residual leakage current signal. The current signal acquisition module is used to acquire the leakage current signal of the transformer area line in real time. The leakage fault location module is integrated inside the leakage analyzer and used in conjunction with an external pulse signal transmitting unit; This is used to accurately locate a leakage fault by injecting a specific frequency detection pulse signal into the transformer area line after a leakage fault is detected, and by combining the transmission attenuation and reflection characteristics of the pulse signal, the location of the leakage fault point is analyzed and calculated. The voltage synchronization acquisition module is electrically connected to the transformer area line through the electrical contact; it is used to synchronously acquire the phase voltage and line voltage signals of the transformer area line. The local data storage module is electrically connected to the storage control interface of the main control module, and is expanded using built-in flash memory and external storage cards. It is used to automatically store historical test data, including test time, test area number, leakage current value, voltage value, fault type, and location information. It supports local query, export, and deletion of data; the storage capacity is expandable to meet the data retention needs of long-term and multiple test areas. The wireless communication module is electrically connected to the communication interface of the main control module and is integrated inside the device to realize wireless data transmission with the power grid operation and maintenance management platform.

3. The portable transformer substation leakage current detection device according to claim 1, characterized in that: A front baffle is hinged to the front opening of the housing, and the front baffle is fixed to the housing by a locking structure.

4. The portable transformer substation leakage current detection device according to claim 3, characterized in that: A counterweight is installed on the front baffle.

5. The portable transformer substation leakage current detection device according to claim 1, characterized in that: The clamping driver includes a motor, a screw, a moving rod, and two sets of connecting rod assemblies. A through-hole is provided on the rear sidewall of the housing, and the two connecting rod assemblies are respectively connected to corresponding crossbars through the through-hole. The moving rod is vertically movably disposed inside the housing. The connecting rod assembly includes a longitudinal sliding block, a first connecting rod, a second connecting rod, and a sliding sleeve. One end of the longitudinal sliding block is fixed to the corresponding crossbar, and the other end extends movably through the through-hole into the housing and is rotatably connected to one end of the first connecting rod. The other end of the first connecting rod is rotatably connected to the sliding sleeve at an upward tilt, and the sliding sleeve is slidably fitted onto the moving rod. One end of the second connecting rod is rotatably connected to the sliding sleeve, and the other end is rotatably connected to the inner wall of the housing at an upward tilt, with the two connecting rods tilted in opposite directions. The screw is horizontally disposed inside the housing and is poweredly connected to the output shaft of the motor outside the housing. The middle part of the moving rod is threaded onto the screw.

6. The portable transformer substation leakage current detection device according to claim 5, characterized in that: A slide rail is vertically installed on the inner wall of the housing, and two crossbars are vertically slidably installed on the slide rail.

7. The portable transformer substation leakage current detection device according to claim 5, characterized in that: An insulating rod is horizontally fixed to the side of the electrical contact near the corresponding crossbeam. The corresponding crossbeam has a cavity inside, and a sliding rod is vertically fixed inside the cavity. The insulating rod extends into the cavity through a strip hole opened on the corresponding crossbeam. A vertical hole is opened on the insulating rod, and the insulating rod is slidably sleeved on the sliding rod through the vertical hole. A spring is sleeved on the sliding rod, and the spring is located on the sliding rod away from the cable and abuts against the insulating rod.

8. The portable transformer substation leakage current detection device according to claim 1, characterized in that: The end of the electrical contact near the cable has an arc-shaped notch that matches the shape of the cable's outer wall.

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