Direct-current cable in-operation checking device

Abstract

The utility model discloses a DC cable in-operation checking device comprising a host and a slave, and the host is in signal connection with the slave through a communication module. The host is arranged at a direct current feeder end of a direct current cable bus, the host comprises a multi-path direct current acquisition module, a first central processor and an A / D conversion module which are electrically connected with one another, and the multi-path current clamp is connected to the direct current feeder end in a clamping manner and is used for acquiring current change signals of the multi-path direct current feeder end; the slave machine is arranged at the load end of the cable to be identified, the slave machine comprises a controllable load switching module and a second central processing unit, and the second central processing unit generates a step signal and is used for controlling the controllable load switching module to perform periodic switching in the direct current loop. The DC cable in-operation checking device automatically judges whether the cable connected in parallel with the slave computer and the cable tested by the host computer are the same cable or not, improves the checking accuracy, and achieves the checking of the DC loop cable.

Description

Technical Field

[0001] This utility model belongs to the field of power grid technology, and specifically relates to a DC cable in-service verification device. Background Technology

[0002] DC power supply systems are widely used in secondary power grid disciplines such as power communication, relay protection, and automation. Before putting DC electrical equipment into operation, decommissioning, undergoing maintenance, or changing its operating mode, the DC wiring of the equipment needs to be verified. For some substations, due to long operating times and inadequate acceptance testing, cable labels may be faded, detached, or contain incorrect information. Verifying DC cables solely based on labels may lead to accidental power outages, causing unplanned power production interruptions or even power accidents. Traditional DC cable verification methods are divided into in-operation verification and out-of-operation verification. Out-of-operation verification is easier but requires shutting down the equipment, affecting normal power grid operations. Furthermore, if wiring errors exist, the risk of accidental equipment shutdown is significant. In-operation verification requires manual visual inspection along the cable laying path from start to finish. This method is not only inefficient, but also extremely difficult when cables pass through cable trays, shafts, and walls. Visual fatigue can easily lead to incorrect verification results, resulting in accidental equipment shutdowns, and even electric shock risks from poorly insulated cables.

[0003] In recent years, various cable cross-connection devices have emerged to improve the efficiency and accuracy of cross-connection. One method involves applying a specific frequency pulse signal to one end of the cable under test using current clamp coupling, and detecting the presence of the signal at the other end to determine the identity of both ends of the cable. However, this method is not very accurate because multi-circuit cables are often bundled together. The pulse signal in the detection circuit can spread to all adjacent circuits through electromagnetic induction, making it impossible to effectively verify the cable. Another method involves installing instruments at both ends of the cable for short-distance cross-connection after shutdown; or applying a specific frequency voltage signal at the load end while the cable is in operation, and detecting and identifying current changes at the other end. This method improves identification efficiency but affects the quality of DC power supply and interferes with the normal operation of the power supply and equipment. Utility Model Content

[0004] To address the aforementioned issues, this invention provides a DC cable in-service verification device that can quickly and accurately verify the condition of straight cables without interrupting operation or affecting DC power supply quality, thereby saving labor costs and reducing workload.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A DC cable in-service verification device is used to verify DC wiring conditions. It includes a master unit and a slave unit. The master unit establishes a signal connection with the slave unit via a communication module. The master unit is located at the DC feeder end of the DC cable busbar. The master unit includes a multi-channel DC current acquisition module, a first central processing unit (CPU), and an A / D conversion module, all electrically connected to each other. The multi-channel DC current acquisition module has a multi-channel current clamp connected to the DC feeder end for acquiring current change signals from multiple DC feeder ends. The A / D conversion module is located between the multi-channel DC current acquisition module and the first CPU for amplifying and converting the acquired current change signals into high-low level change signals. The slave unit is located at the load end of the cable to be identified. The slave unit includes a controllable load switching module and a second CPU. The second CPU generates a step signal to control the controllable load switching module to periodically switch in the DC circuit. The master unit receives the response signal from the slave unit and compares the acquired signal from the master unit with the characteristic current signal from the slave unit through the first CPU.

[0007] Preferably, the controllable load switching module includes a relay and a variable resistor. The relay is used to receive a step signal. The second central processing unit controls the closing and opening actions of the relay and controls the variable resistor to perform periodic switching in the DC circuit.

[0008] Preferably, the slave device further includes an NMOS transistor, which is disposed between the second central processing unit and the relay for controlling the on / off state of the circuit.

[0009] Preferably, the host and the slave are connected via a communication module, which is either carrier communication or wireless communication.

[0010] Preferably, the host computer is provided with a first display module and a first storage module, the first display module and the first storage module being communicatively connected to the first central processing unit, and the slave computer is provided with a second display module and a second storage module, the second display module and the second storage module being communicatively connected to the second central processing unit.

[0011] Compared with existing technologies, the beneficial effects of this utility model are as follows:

[0012] This DC cable verification device automatically determines whether the cable connected to the slave device and the cable measured by the master device are the same cable by comparing the periodicity of the current change signal collected by the master device with that of the characteristic current signal of the slave device. This improves the verification accuracy and enables the verification of DC circuit cables. The device does not require interruption of the power supply circuit, disconnection of the wiring, or change of the equipment power supply voltage, thus improving the safety of the verification operation. It transforms the verification work that requires multiple people into a simple signal measurement task, reducing the complexity and workload of the verification work. Attached Figure Description

[0013] Figure 1 This is a flowchart of the DC cable in-operation verification device of this utility model;

[0014] Figure 2 This is a schematic diagram of the installation of the DC cable in the verification device of this utility model;

[0015] Figure 3 This is a schematic diagram of the main unit process of the DC cable verification device in operation according to this utility model;

[0016] Figure 4 This is a schematic diagram of the process flow of the DC cable in operation verification device of this utility model.

[0017] In the attached diagram, 1-host, 11-multi-channel DC current acquisition module, 12-first central processing unit, 13-A / D conversion module, 14-multi-channel current clamp, 15-first display module, 16-first storage module, 2-slave, 21-controllable load switching module, 211-relay, 212-variable resistor, 22-second central processing unit, 23-second display module, 24-second storage module, 3-communication module. Detailed Implementation

[0018] To make the objectives, technical solutions and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0019] Where the following description relates to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this invention as detailed in the appended claims.

[0020] In the description of this utility model, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of these terms in this utility model based on the specific circumstances. Furthermore, in the description of this utility model, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] To resolve the above issues, please refer to [link / reference]. Figures 1 to 4 This utility model provides a DC cable in-service verification device for verifying DC wiring conditions. It includes a host 1 and a slave 2. The host 1 establishes a signal connection with the slave 2 via a communication module 3. The host 1 is located at the DC feeder end of the DC cable busbar. The host 1 includes a multi-channel DC current acquisition module 11, a first central processing unit 12, and an A / D conversion module 13, all electrically connected to each other. The multi-channel DC current acquisition module 11 has a multi-channel current clamp 14, which is clamped and connected to the DC feeder end for acquiring current change signals from multiple DC feeder ends. The A / D conversion module 13 is configured... Between the multi-channel DC current acquisition module 11 and the first central processing unit 12, the acquired current change signal is amplified and converted into a high-low level change signal; the slave device 2 is located at the load end of the cable to be identified, and the slave device 2 includes a controllable load switching module 21 and a second central processing unit 22. The second central processing unit 22 generates a step signal to control the controllable load switching module 21 to perform periodic switching in the DC circuit; wherein, the host device 1 receives the response signal of the slave device 2 and compares the acquisition signal of the host device 1 and the characteristic current signal of the slave device 2 through the first central processing unit 12.

[0023] In optional embodiments, such as Figure 1As shown, the controllable load switching module 21 includes a relay 211 and a variable resistor 212. The relay 211 is used to receive a step signal. The second central processing unit 22 controls the closing and opening of the relay 211 and controls the variable resistor 212 to perform periodic switching in the DC circuit.

[0024] In an optional embodiment, the slave device 2 further includes an NMOS transistor, which is disposed between the second central processing unit 22 and the relay 211 for controlling the switching of the circuit. An NMOS transistor, or N-type metal-oxide-semiconductor field-effect transistor, primarily functions as a switch and an isolation transistor. When used as a switch, an NMOS transistor can achieve signal switching (high-low level switching) and voltage switching.

[0025] In optional embodiments, such as Figure 1 As shown, the host 1 and the slave 2 are connected via a communication module 3, which can be either carrier communication or wireless communication. In this embodiment, the actual application is not limited to these two communication methods.

[0026] In optional embodiments, such as Figure 1 As shown, the host machine 1 is equipped with a first display module 15 and a first storage module 16, which are communicatively connected to the first central processing unit 12. The slave machine 2 is equipped with a second display module 23 and a second storage module 24, which are communicatively connected to the second central processing unit 22. The host machine 1 and the slave machine 2 can intuitively display the core-line test results through the first display module 15 and the second display module 23, respectively, and simultaneously save the core-line test results using the first storage module 16 and the second storage module 24, respectively, facilitating on-site verification and recording by equipment maintenance personnel.

[0027] like Figures 3 to 4 The verification process of the DC cable verification instrument shown is as follows: Slave unit 2 performs load switching and applies a current sequence; host unit 1 performs multi-channel current detection; host unit 1 and slave unit 2 coordinate their work through communication module 3 to achieve cable verification, identifying the corresponding relationship from multiple feeders at once. Specifically, as shown... Figure 3 As shown, host 1 uses communication module 3 to send a synchronous acquisition command to slave 2, notifying slave 2 to start verification. Host 1 synchronously enters the current acquisition and identification state, and performs current sampling synchronously through multi-channel current clamp 14; as Figure 4As shown, after receiving the instruction, slave device 2 responds to host 1 and enters the test state. After slave device 2 presses the test switch, the second central processing unit 22 generates a 0.5Hz square wave voltage signal to control the on and off of the NMOS transistor, and then controls the relay 211 to perform the closing and opening action, and controls the variable resistor 212 to periodically switch on and off in the DC circuit. After slave device 2 is connected in parallel with the cable load, the DC circuit voltage remains unchanged and the resistance changes periodically. According to Ohm's law, a periodically changing characteristic current signal will be generated on the circuit cable.

[0028] After receiving the response signal sent by the slave device 2, the host device 1 collects the current change signal on the power supply side through the multi-channel current clamp 14, and filters and amplifies it through the A / D conversion module 13, converting it into a high-low level change signal and inputting it into the first central processing unit 12. The first central processing unit 12 determines whether the signal detected by the host device 1 and the characteristic current signal are consistent based on the calculated number of pulses, and automatically determines whether the cable connected in parallel by the slave device 2 and the cable measured by the host device 1 are the same cable. If the periodic changes are the same, they belong to the same cable; if the periodic changes are different, they belong to different cables.

[0029] In summary, this DC cable verification device uses characteristic current signals for cable verification, eliminating the need for visual inspection and overcoming the drawbacks of manual verification in cable shafts and enclosed cable trays. It employs a single wiring and automatic identification system for one-to-many cable verification, reducing manpower requirements; 1-2 people can complete the cable verification, improving work efficiency. Cable verification can be performed directly under energized conditions without shutting down operating equipment, thus not affecting the company's economic benefits. Verification is based on the synchronous current changes of the applied load, increasing the accuracy of the verification without impacting the power supply quality. Both the main unit 1 and the slave unit 2 can visually display the verification results and save them, facilitating on-site verification and recording by equipment maintenance personnel.

[0030] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0031] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A DC cable in-service verification device, used to verify DC wiring conditions, characterized in that, The system includes a master unit and a slave unit. The master unit establishes a signal connection with the slave unit via a communication module. The master unit is located at the DC feeder end of the DC cable busbar. The master unit includes a multi-channel DC current acquisition module, a first central processing unit, and an A / D conversion module that are electrically connected to each other. The multi-channel DC current acquisition module has a multi-channel current clamp connected to the DC feeder end for acquiring current change signals from multiple DC feeder ends. The A / D conversion module is located between the multi-channel DC current acquisition module and the first central processing unit for amplifying and converting the acquired current change signals into high-low level change signals. The slave unit is located at the load end of the cable to be identified. The slave unit includes a controllable load switching module and a second central processing unit. The second central processing unit generates a step signal and controls the controllable load switching module to periodically switch in the DC circuit. The master unit receives the response signal from the slave unit and compares the acquired signal of the master unit with the characteristic current signal of the slave unit through the first central processing unit.

2. The DC cable in-service verification device according to claim 1, characterized in that, The controllable load switching module includes a relay and a variable resistor. The relay is used to receive a step signal. The second central processing unit controls the closing and opening of the relay and controls the variable resistor to periodically switch in the DC circuit.

3. The DC cable in-service verification device according to claim 2, characterized in that, The slave device also includes an NMOS transistor, which is disposed between the second central processing unit and the relay for controlling the on / off state of the circuit.

4. The DC cable in-service verification device according to any one of claims 1 to 3, characterized in that, The host and the slave are connected via a communication module, which can be either carrier communication or wireless communication.

5. The DC cable in-service verification device according to any one of claims 1 to 3, characterized in that, The host computer is equipped with a first display module and a first storage module, the first display module and the first storage module being communicatively connected to the first central processing unit. The slave computer is equipped with a second display module and a second storage module, the second display module and the second storage module being communicatively connected to the second central processing unit.

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