A circuit for detecting the location of a sparkover leakage

Abstract

This invention aims to provide a fault location detection circuit for arcing and leakage current, capable of accurately locating faulty sections, compatible with AC / DC systems, and dynamically expanding detection nodes according to actual needs to meet the electrical safety detection requirements of different application scenarios. This invention includes a current loop comprising several electrical components connected in series. Current acquisition modules are installed at the beginning and end of the current loop, as well as at the connection points of adjacent electrical components. The current acquisition modules are connected to a control module, which in turn is connected to an alarm output module. The control module calculates the current difference between adjacent nodes and compares it with a dynamic threshold. The alarm output module triggers an alarm or disconnects the faulty circuit. This invention applies to the technical field of electrical safety detection.

Description

Technical Field

[0001] This invention relates to the technical field of electrical safety testing, and in particular to a positioning detection circuit for arcing leakage. Background Technology

[0002] In AC / DC high and low voltage power distribution systems, as cables or equipment age, aging issues become increasingly prominent, easily leading to leakage or arcing faults. For example, electrical fires caused by leakage and arcing due to cable / equipment aging frequently occur in series-connected photovoltaic modules, energy storage batteries, and capacitors and resistors in series in high-voltage circuits. Currently, there is a lack of timely and effective detection solutions to prevent such accidents.

[0003] In the field of electrical safety testing, existing technologies have many shortcomings:

[0004] 1. Although traditional residual current transformers can detect leakage current, they can only determine that there is a leakage current fault in the system, but cannot further locate the specific section where the fault occurred. This makes it like searching for a needle in a haystack for maintenance personnel, resulting in extremely low efficiency.

[0005] 2. DC systems have different characteristics from AC systems. DC systems do not have zero-crossing points, which causes traditional detection methods and devices based on the zero-crossing characteristics of AC systems to completely fail in DC systems, making effective detection impossible.

[0006] 3. For multi-stage series systems, such as battery packs and photovoltaic arrays, when a fault occurs in a certain part, it is difficult to accurately locate the fault due to the complex system structure and lack of effective detection methods, which affects the normal operation and maintenance of the system.

[0007] 4. The existing detection devices have fixed node settings, making it difficult to dynamically expand according to actual needs. They also have poor adaptability when facing systems of different sizes and structures.

[0008] For example, Chinese patent publication number CN104833893B discloses a leakage current detection system and method, and Chinese patent publication number CN208537658U discloses an intelligent alarm leakage current detection terminal.

[0009] For example, Chinese patent CN115631594A discloses a system and method for arcing detection and alarm of combiner boxes. The former two are designed for low-voltage distribution area leakage detection, while the latter is an arcing detection system for photovoltaic power generation. However, it does not report different levels of leakage based on their severity. When multiple devices are tested simultaneously, multiple alarms will occur, and some of the reported data is not relevant to the staff, thus affecting analysis efficiency. Therefore, it is necessary to provide an arcing leakage location detection circuit that can accurately locate the fault section, is compatible with AC / DC systems, and dynamically expands the detection nodes according to actual needs to meet the electrical safety detection requirements of different application scenarios. Utility Model Content

[0010] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a location detection circuit for arcing leakage, which can accurately locate the fault section, is compatible with AC / DC systems, and can dynamically expand the detection nodes according to actual needs to meet the requirements of electrical safety detection in different application scenarios.

[0011] The technical solution adopted by this utility model is as follows: This utility model includes a current loop, the current loop includes a number of electrical components connected in series, and a current acquisition module is provided between the beginning end of the current loop, the end end of the current loop, and the beginning end of the current loop.

[0012] As can be seen from the above scheme, by comparing whether the difference between the current acquisition modules exceeds a preset threshold, it is determined that an arcing or leakage fault has occurred in the current loop. By setting the current acquisition modules between the beginning and end of the current loop, the range in which the arcing or leakage fault occurs in the current loop can be determined. Furthermore, this application has the following advantages:

[0013] Precise location: By setting current detection nodes at multiple key locations in the current loop and analyzing the current difference between adjacent nodes, this circuit can pinpoint the fault section within ±0.5 meters. Compared with traditional detection devices, this greatly improves the accuracy of fault location and provides strong support for maintenance personnel to quickly and accurately troubleshoot faults.

[0014] Dynamic expansion: The number of current detection nodes can be flexibly configured according to actual needs. Whether it is a small electrical system or a large and complex photovoltaic array, energy storage battery pack, etc., effective fault detection can be achieved by increasing or decreasing the number of nodes, which greatly enhances the adaptability of the device to different systems.

[0015] High versatility: This circuit is applicable to both AC and DC systems, and the leakage current detection accuracy reaches the milliampere level (≥10mA). It can reliably detect arcing leakage faults in both AC power distribution systems and DC power supply systems, making it widely applicable.

[0016] Low cost: Through reasonable design and node arrangement, this circuit reduces the need for independent detection devices. Compared with the traditional method of combining multiple independent detection devices, the hardware cost is reduced by about 40%, which has high economic benefits.

[0017] In a preferred embodiment, the current acquisition module is connected to a control module, the control module including an operational amplifier, a comparator, and an MCU module. The current acquisition module is connected to the MCU module via the operational amplifier and the comparator. The MCU module is connected to an alarm output module and an alarm module.

[0018] A preferred embodiment is that, when the current loop is a DC battery pack system, the series structure of the DC battery pack is: battery pack output positive terminal → battery pack (3 cells) → load → battery pack output positive and negative terminals; the current acquisition module is provided at the positive output terminal of the battery pack, the negative terminal of the second cell, and the negative output terminal of the battery pack.

[0019] A preferred embodiment is that when the current loop is a photovoltaic power generation system, the series structure of the photovoltaic power generation system is photovoltaic string → input combiner box; the current acquisition module is provided at the positive terminal of the input combiner box, the positive terminal of the third component, the positive terminal of the sixth component, and the negative terminal of the input combiner box.

[0020] In a preferred embodiment, the control module is connected to the host computer via a communication module, and the control module transmits the fault location results to the host computer.

[0021] In a preferred embodiment, the current acquisition module serves as a current detection node, which is distributed at the connection points of Hall sensors, shunt resistors, or embedded in cables or devices.

[0022] In a preferred embodiment, the control module includes an operational amplifier, a comparator, and an MCU module. The current acquisition module is connected to the MCU module via the operational amplifier and the comparator. The MCU module is connected to the alarm output module and the communication module. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of this utility model applied to a DC battery pack system;

[0024] Figure 2 This is a structural schematic diagram of the application of this utility model in a photovoltaic power generation system;

[0025] Figure 3 This is a schematic diagram of the structural principle of this utility model applied to supercapacitors;

[0026] Figure 4This is a schematic diagram of the structure of this utility model applied to high-voltage filtering and compensation capacitors;

[0027] Figure 5 This is a schematic diagram of the structural principle of this utility model applied to AC communication;

[0028] Figure 6 This is a structural block diagram of the present invention;

[0029] Figure 7 This is the circuit schematic of the comparator amplifier. Detailed Implementation

[0030] like Figure 1-5 The following is an example. Figure 6 As shown in the structural block diagram, in this embodiment, the present invention includes a current loop, which includes several electrical components connected in series. The electrical components include switches, wires, loads, or various electrical components and devices. A current acquisition module 1 is provided at the beginning end of the current loop, the end end of the current loop, and the connection point of adjacent electrical components. The current acquisition module 1 is connected to a control module 2. The control module 2 includes an operational amplifier 5, a comparator 6, and an MCU module 7. The current acquisition module 1 is connected to the MCU module 7 via the operational amplifier 5 and the comparator 6. The MCU module 7 is connected to an alarm output module 3 and an alarm module 4.

[0031] The current acquisition module 1 or two comparison acquisition modules 1 transmit the current signal to the operational amplifier 5 for differential amplification, and then send it to the MCU module 7 and the comparator 6 for data comparison and calculation for data processing. The MCU module 7 outputs to the alarm output module 3 and the alarm module 4. The control module 2 is used to calculate the current difference between adjacent nodes and compare it with a dynamic threshold. The alarm output module 3 is used for communication output, transmitting data to various data processing and transmission devices such as edge computing gateways and communication modules, and finally transmitting the data to the monitoring platform server. The alarm output module 3 is used to trigger an alarm or disconnect a fault circuit. The comparator 6 can output a fast alarm output signal. The alarm module 4 is used to quickly trigger an alarm or disconnect a fault circuit.

[0032] In the embodiment described above, the arcing or leakage fault zone of the current loop is determined by comparing whether the difference between two adjacent current acquisition modules 1 exceeds a preset threshold.

[0033] The current acquisition module 1 is installed at the beginning, end, and connection points of adjacent series electrical components of the current loop. As current detection nodes, these modules, through proper arrangement, can comprehensively collect current information from different locations within the current loop. Each current detection node converts the current signals at different nodes into detectable and processable electrical signals, thereby enabling the acquisition of current values ​​at each node. Data from adjacent current acquisition modules 1 can also be wirelessly transmitted to the MCU module 7. By comparing data with the same timestamp and then digitally filtering to obtain the difference signal, the adaptability to the field is improved.

[0034] The control module 2 is the core of the entire circuit. It receives the current values ​​collected by each current detection node and calculates the current difference between adjacent nodes. When the current difference between adjacent nodes is compared and calculated by the control module 2 through the comparator 6 and the MCU module 7, and the calculated current difference exceeds a preset threshold, the alarm output module 3 is triggered, thereby issuing an alarm signal, or cutting off the faulty circuit according to a preset program to ensure system safety. The alarm module 4 transmits data to the monitoring platform server via digital communication.

[0035] like Figure 1 As shown, in this embodiment, when the current loop is a DC battery pack system, the series structure of the DC battery pack system is positive terminal → 3 battery cells → load → negative terminal; the current acquisition module 1 is provided at the positive output terminal of the battery pack, the negative terminal of the second battery cell, and the negative output terminal of the battery pack.

[0036] Let the detection value at the positive output terminal of the battery pack be I1, the detection value at the negative terminal of the second battery be I2, and the detection value at the negative output terminal of the battery pack be I3. When the casing of the second battery experiences leakage, the difference between I1 and I2 exceeds a threshold, while the current values ​​of I2 and I3 show no significant difference. Based on this, the system locks the fault to be located between the positive output terminal of the battery pack and the positive terminal of the second battery.

[0037] like Figure 2 As shown, in this embodiment, when the current loop is a photovoltaic power generation system, the series structure of the photovoltaic power generation system is a photovoltaic string of N components → input combiner box; the current acquisition module 1 is provided at the positive terminal of the input combiner box, the positive terminal of the 3rd component, the positive terminal of the 6th component, and the negative terminal of the input combiner box.

[0038] Let I1 be the positive terminal of the input combiner box, I2 be the output terminal of the third component, I3 be the output terminal of the sixth component, and I4 be the negative terminal of the input combiner box. If the difference between I1 and I1+n is normal, it indicates that there is no leakage or arcing in this section. When the difference between I1 and I1+n exceeds the threshold, the system locks the fault in the section between I1 and I1+N. In this section, when the difference between In and In+1 exceeds the threshold, it can be determined that there is leakage or arcing in the section between In and In+1, which further triggers the UAV to inspect the line in this section.

[0039] like Figures 1 to 7 As shown, in this embodiment, the data from the control module 2 can be communicated with the host computer via the alarm module 4, and the control module 2 transmits the fault location result to the host computer. The alarm module 4 includes various wired / wireless communication modules; the data from the control module 2 is input to the comparator 6, the comparator 6 compares it with the threshold, and outputs an alarm signal to the alarm output module 3, triggering the alarm module 4 to issue an alarm signal; alternatively, the comparator 6 can directly output an alarm signal according to a preset threshold to quickly disconnect the faulty circuit.

[0040] like Figures 1 to 7 As shown, in this embodiment, the current acquisition module 1 serves as a current detection node. The current acquisition module 1 can be any current detection element such as a Hall sensor, shunt resistor, or current transformer, and is distributed and installed as an acquisition node at the connection of a switch, conductor, or device.

[0041] In this embodiment, the current detection node can also be installed at the cable or equipment connection by embedding the cable. This installation method not only makes the device structure more compact, but also supports dynamic addition or reduction of the number of nodes, which can be flexibly adjusted according to actual detection needs, greatly improving the applicability of the device.

[0042] In this embodiment, the preset threshold is not fixed, but is dynamically adjusted according to the detection section length and rated current, with an adjustment range of 5%-20%. Through this dynamic adjustment mechanism, the device can maintain high detection accuracy in different system environments.

[0043] In this embodiment, this application is applicable to complex systems such as photovoltaic arrays, energy storage battery packs, high-voltage filters, compensation capacitors, and AC / DC converters.

[0044] In this embodiment, the control module 2 connects to the host computer via CAN bus, RS485, or wireless communication, facilitating the timely transmission of detection results and fault information to the upper-level control system, enabling remote monitoring and management by operators. The MCU module 7 uses a high-performance microcontroller (such as ARM or STC series chips) as its core processing unit, coupled with a high-precision A / D conversion circuit, to convert the analog current signal collected by the current detection node into a digital signal for calculation and processing by the microcontroller. Simultaneously, the MCU module 7 also integrates a communication interface circuit, selecting CAN bus, RS485, or a wireless communication module (such as Wi-Fi, Bluetooth, or 4G / 5G communication module) as the alarm module 4 to achieve communication with the host computer. Furthermore, to ensure the stable operation of the control module 2, a corresponding power management circuit is required to provide a stable power supply to each circuit component.

[0045] Although the embodiments of this utility model are described with reference to actual solutions, they do not constitute a limitation on the meaning of this utility model. For those skilled in the art, modifications to the implementation schemes and combinations with other schemes based on this specification are obvious.

Claims

1. A positioning detection circuit for arcing leakage, comprising a current loop, wherein the current loop comprises a plurality of electrical components connected in series, characterized in that: A current acquisition module (1) is provided at the beginning of the current loop, the end of the current loop, and between the beginning and the end of the current loop.

2. The arcing leakage current positioning detection circuit according to claim 1, characterized in that: The current acquisition module (1) is connected to a control module (2). The control module (2) includes an operational amplifier (5), a comparator (6), and an MCU module (7). The current acquisition module (1) is connected to the MCU module (7) via the operational amplifier (5) and the comparator (6). The MCU module (7) is connected to an alarm output module (3) and an alarm module (4).

3. The arcing leakage current positioning detection circuit according to claim 1, characterized in that: When the current loop is a DC battery pack system, the series structure of the DC battery pack is battery pack output positive terminal → battery pack → load → battery pack output positive terminal and negative terminal; the current acquisition module (1) is provided at the positive terminal of the battery pack, the negative terminal of the second battery, and the negative terminal of the battery pack.

4. The arcing leakage current positioning detection circuit according to claim 1, characterized in that: When the current loop is a photovoltaic power generation system, the series structure of the photovoltaic power generation system is photovoltaic string → input combiner box; the current acquisition module (1) is provided at the positive terminal of the input combiner box, the positive terminal of the third component, the positive terminal of the sixth component, and the negative terminal of the input combiner box.

5. The arcing leakage current positioning detection circuit according to claim 2, characterized in that: The control module (2) is connected to the host computer via the communication module, and the control module (2) transmits the fault location results to the host computer.

6. The arcing leakage current positioning detection circuit according to claim 1, characterized in that: The current acquisition module (1) serves as a current detection node, which is distributed at the connection points of Hall sensors, shunt resistors, cables, and equipment. The current detection node is installed at the cable and equipment connection point using an embedded cable method.

Images