A method and system for detecting the circulating current of coaxial cables with a cross-connected grounding method

Abstract

The present invention discloses a coaxial cable circulating current detection method and system with a cross-connected grounding method. The flexible Rogowski coil is screwed into a forward loop and a reverse loop, so that the forward loop and the reverse loop form an 8-shaped structure. The grounding wire of the phase to be measured and the main grounding wire are simultaneously sleeved in the forward loop, and the grounding wire of the other phase is sleeved in the reverse loop. Finally, by obtaining the current detection value of the flexible Rogowski coil, the actual circulating current of the grounding wire of the phase to be measured is obtained. Based on the relationship between the total grounding current and the circulating current value of each phase in the cross-connected grounding method, this method screws the flexible Rogowski coil into a forward loop and a reverse loop, and directly calculates the actual circulating current of the phase to be measured by reading the current detection value. Using this method can conveniently, quickly, safely and accurately perform the circulating current test, avoid the cumbersome operation of repeatedly opening and closing the circulating current box during the circulating current detection, reduce the safety risk of live working, and can accurately and reliably measure the circulating current value.

Description

Technical Field

[0001] The present invention belongs to the field of cross-connected grounding detection, and particularly relates to a method and system for detecting the circulating current of coaxial cables with a cross-connected grounding method. Background Art

[0002] In the practical application of high-voltage single-core cables, the detection of the circulating current in the cable sheath is an important link to ensure the safe and stable operation of the cable. The cross-connected grounding method is a common grounding method in transmission cables. It connects the metal sheaths of different phases through coaxial cables to form a complex grounding network. Although this grounding method helps to reduce the induced voltage and circulating current on the cable metal sheath, it also increases the difficulty of detecting the circulating current. Since the circulating currents in the inner and outer cores of the coaxial cable are independent of each other and may not be synchronized, traditional detection methods are difficult to accurately distinguish and measure the circulating currents of each phase, resulting in the inability to comprehensively and accurately evaluate the grounding status and operating conditions of the cable.

[0003] Currently, two main methods are generally used in the industry to detect the circulating current: one is to directly clamp the value of the circulating current with a clamp ammeter. The clamp ammeter is widely used because of its simple operation and fast measurement. However, when the cable uses the cross-connected grounding method, the inner and outer cores of the coaxial cable carry the circulating currents of different-phase metal sheaths respectively. At this time, if a clamp ammeter is directly used to clamp the coaxial cable for measurement, the obtained current value is actually the vector superposition value of the circulating currents in the inner and outer cores. Due to the possible cancellation or enhancement effects of vector superposition, the measured value may be greater than or less than the actual current value, resulting in the inability to accurately reflect the true operating condition of the cable. The other is to directly set the value of the circulating current with a Rogowski coil and transmit it back to the remote end through an optical fiber for monitoring. As an AC current sensor, the Rogowski coil has a wide frequency response range and fast instantaneous response ability, and is suitable for the measurement of high-frequency and large currents. However, in the conventional detection method, in a cross-connected grounding system, due to the possible different directions and magnitudes of the circulating currents in the inner and outer cores of the coaxial cable, the Rogowski coil will also be affected by vector superposition when setting the current; it is impossible to give a timely warning against risks such as excessive circulating current, resulting in an impact on the operation of power equipment.

[0004] It can be seen that when using the existing coaxial cable circulating current detection measures for cross-connected grounding, when measuring the coaxial cable in a cross-connected grounding system, the measured actual circulating current value is the vector sum of the inner and outer cores of the phase to be measured, and its value may be greater than or less than the actual current value, making it difficult to reflect the true operating condition of the cable. Due to the influence of the vector superposition effect, the measurement accuracy is difficult to guarantee. Summary of the Invention

[0005] The object of the present invention is to provide a method and system for detecting the circulating current of coaxial cables with a cross-connected grounding method, so as to solve the technical problem that it is difficult to guarantee the measurement accuracy when measuring the coaxial cables in the cross-connected grounding system due to the influence of the vector superposition effect by using the existing coaxial cable circulating current detection measures with the cross-connected grounding method.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A method for detecting the circulating current of coaxial cables with a cross-connected grounding method, comprising:

[0008] Screw the flexible Rogowski coil into a forward loop and a reverse loop, so that the forward loop and the reverse loop form an 8-shaped structure;

[0009] Simultaneously sleeve the ground wire of the phase to be measured and the main ground wire into the forward loop, and sleeve the ground wire of another phase into the reverse loop, wherein the head of the ground wire of another phase is cross-connected with the tail of the ground wire of the phase to be measured;

[0010] Obtain the current detection value of the flexible Rogowski coil at present, and calculate the actual circulating current of the ground wire of the phase to be measured.

[0011] Further, the detection method for the actual circulating current of the ground wire of phase A specifically comprises:

[0012] Simultaneously sleeve the ground wire of phase A and the main ground wire into the forward loop, and sleeve the ground wire of phase B into the reverse loop;

[0013] Obtain the first detection value of the flexible Rogowski coil, and calculate the actual circulating current of the ground wire of phase A.

[0014] Further, the specific formula for the actual circulating current of the ground wire of phase A is:

[0015] The actual circulating current of the ground wire of phase A = the first detection value of the flexible Rogowski coil ÷ 3.

[0016] Further, the detection method for the actual circulating current of the ground wire of phase B specifically comprises:

[0017] Simultaneously sleeve the ground wire of phase B and the main ground wire into the forward loop, and sleeve the ground wire of phase C into the reverse loop;

[0018] Obtain the second detection value of the flexible Rogowski coil, and calculate the actual circulating current of the ground wire of phase B.

[0019] Further, the specific formula for the actual circulating current of the ground wire of phase B is:

[0020] The actual circulating current of the ground wire of phase B = the second detection value of the flexible Rogowski coil ÷ 3.

[0021] Further, the method for detecting the actual circulating current of the phase C grounding wire specifically includes:

[0022] Socket the phase C grounding wire and the main grounding wire into the forward loop at the same time, and socket the phase A grounding wire into the reverse loop;

[0023] Obtain the third detection value of the flexible Rogowski coil and calculate the actual circulating current of the phase C grounding wire.

[0024] Further, the specific formula for the actual circulating current of the phase C grounding wire is:

[0025] Actual circulating current of the phase C grounding wire = Third detection value of the flexible Rogowski coil ÷ 3.

[0026] Further, the flexible Rogowski coil includes a body, and a coil, a power switch button, a data hold button, a liquid crystal display screen, a voltage input socket and an open coil knob are arranged on the body;

[0027] The coil is fixed to the body through the open coil knob;

[0028] The voltage input socket is opened at the tail of the body and is used to supply power to the flexible Rogowski coil;

[0029] The power switch button and the data hold button are symmetrically arranged. The power switch button is used to turn on and off the flexible Rogowski coil, and the data hold button is used to hold the current detection value;

[0030] The liquid crystal display screen is arranged on the handle of the body and is used to display the detection value.

[0031] Further, the specific calculation formula for the actual circulating current of the grounding wire of the phase to be measured is as follows:

[0032]

[0033]

[0034] Among them, I a represents the detection value of phase A; I b represents the detection value of phase B; I c represents the detection value of phase C; I s represents the total grounding current detection value; A i represents the inner core current value of phase A; B i represents the inner core current value of phase B; C i represents the inner core current value of phase C; A0 represents the outer core current value of phase A; B0 represents the outer core current value of phase B; C0 represents the outer core current value of phase C.

[0035] A coaxial cable circulating current detection system with a cross-connected grounding method, which is used to implement the steps of the coaxial cable circulating current detection method with the above-mentioned cross-connected grounding method, includes:

[0036] A detection value acquisition module, which is used to acquire the current detection value of the flexible Rogowski coil;

[0037] A circulating current calculation module, which is used to calculate the actual circulating current of the grounding wire of the phase to be measured according to the current detection value of the flexible Rogowski coil;

[0038] Among them, the current detection value of the flexible Rogowski coil is obtained through the following method, which specifically includes:

[0039] The flexible Rogowski coil is screwed into a forward loop and a reverse loop, and the forward loop and the reverse loop form an 8-shaped structure; the grounding wire of the phase to be measured and the main grounding wire are simultaneously sleeved in the forward loop, and the grounding wire of another phase is sleeved in the reverse loop, wherein the head of the grounding wire of another phase is cross-connected with the tail of the grounding wire of the phase to be measured.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The present invention provides a coaxial cable circulating current detection method with a cross-connected grounding method. In this method, the flexible Rogowski coil is screwed into a forward loop and a reverse loop, so that the forward loop and the reverse loop form an 8-shaped structure; then the grounding wire of the phase to be measured and the main grounding wire are simultaneously sleeved in the forward loop, and the grounding wire of another phase is sleeved in the reverse loop, and the head of the grounding wire of another phase is cross-connected with the tail of the grounding wire of the phase to be measured; finally, the actual circulating current of the grounding wire of the phase to be measured is calculated by acquiring the current detection value of the flexible Rogowski coil; based on the relationship between the total grounding current and the circulating current value of each phase in the cross-connected grounding method, this method screws the flexible Rogowski coil into a forward loop and a reverse loop, and directly calculates the actual circulating current of the phase to be measured by reading the current detection value; this method can conveniently, quickly, safely and accurately perform the circulating current test, avoids the cumbersome operation of repeatedly opening and closing the circulating current box during the circulating current detection, reduces the safety risk of live working, and can accurately and reliably measure the circulating current value.

[0042] Preferably, in the present invention, the phase A grounding wire and the main grounding wire are simultaneously sleeved inside the forward loop, and the phase B grounding wire is sleeved inside the reverse loop. By obtaining the first detection value of the flexible Rogowski coil, the actual circulating current of the phase A grounding wire is calculated. Similarly, the phase B grounding wire and the main grounding wire are simultaneously sleeved inside the forward loop, and the phase C grounding wire is sleeved inside the reverse loop. By obtaining the second detection value of the flexible Rogowski coil, the actual circulating current of the phase B grounding wire is calculated. And the phase C grounding wire and the main grounding wire are simultaneously sleeved inside the forward loop, and the phase A grounding wire is sleeved inside the reverse loop. By obtaining the third detection value of the flexible Rogowski coil, the actual circulating current of the phase C grounding wire is calculated. The specific operation process in practical applications is clarified, which helps the operator quickly and accurately obtain the circulating current data of each phase grounding wire, improving the detection efficiency and accuracy.

[0043] Preferably, in the present invention, the flexible Rogowski coil includes a body, a coil, a power switch button, a data hold button, a liquid crystal display screen, a voltage input socket, and an open coil knob. Such a design makes the flexible Rogowski coil easier to operate and maintain, while also improving its stability and durability. The detection value is displayed in real time through the liquid crystal display screen, further enhancing the user experience and detection efficiency.

[0044] Preferably, in the present invention, based on the principle that in cross-bonding grounding, there is a special relationship between the actual circulating current of the grounding wire of the phase to be measured and the total grounding current. The total grounding current is the sum of the core currents of each phase, and the detected current of each phase is the vector sum of the core current and the sheath current of each phase. And the sheath current of each phase is equal to the reverse core current value of the cross-bonding phase. Thus, the core current of each phase, that is, the actual circulating current value of each phase, can be obtained. Based on this principle, it is possible to conveniently and quickly detect the actual circulating current value of each phase accurately and reliably.

[0045] The present invention also provides a coaxial cable circulating current detection system with a cross-bonding grounding method for implementing the steps of the above coaxial cable circulating current detection method. Using this system can conveniently and quickly complete the measurement of the coaxial cable circulating current value, and can give a timely warning against risks such as excessive circulating current, avoiding affecting the operation of power equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic structural diagram of the flexible Rogowski coil provided by an embodiment of the present invention;

[0047] Figure 2 It is a flowchart of a coaxial cable circulating current detection method with a cross-bonding grounding method provided by an embodiment of the present invention;

[0048] Figure 3 It is a detection principle diagram of a coaxial cable circulating current detection method with a cross-bonding grounding method provided by an embodiment of the present invention;

[0049] Figure 4 Schematic diagram of the internal structure of the cross - connected grounding box provided by the embodiment of the present invention;

[0050] Figure 5 Detection schematic diagram of the actual circulating current of the phase A grounding wire of the coaxial cable circulating current detection method with a cross - connected grounding method provided by the embodiment of the present invention;

[0051] Figure 6 Detection schematic diagram of the actual circulating current of the phase B grounding wire of the coaxial cable circulating current detection method with a cross - connected grounding method provided by the embodiment of the present invention;

[0052] Figure 7 Detection schematic diagram of the actual circulating current of the phase C grounding wire of the coaxial cable circulating current detection method with a cross - connected grounding method provided by the embodiment of the present invention.

[0053] Reference numerals:

[0054] 1 - Coil, 2 - Power switch button, 3 - Data hold button, 4 - Liquid crystal display screen, 5 - Voltage input socket, 6 - Coil opening knob. Detailed implementation manners

[0055] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0056] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only embodiments.

[0057] Embodiment 1

[0058] As mentioned in the background art, currently, two main methods are generally used in the industry to detect the circulating current: one is to directly clamp the value of the circulating current using a clamp ammeter, which is widely used because of its simple operation and fast measurement. However, when the cable adopts the cross-connected grounding method, different-phase metal sheath circulating currents flow in the inner and outer cores of the coaxial cable respectively; at this time, if a clamp ammeter is directly used to clamp the coaxial cable for measurement, the obtained current value is actually the vector superposition value of the inner and outer core circulating currents; due to the possible cancellation or enhancement effects of vector superposition, the measured value may be greater than or less than the actual current value, resulting in the inability to accurately reflect the true operating condition of the cable; the other is to directly set the circulating current value using a Rogowski coil and transmit it back to the remote end through an optical fiber for monitoring. As an alternating current sensor, the Rogowski coil has a wide frequency response range and fast instantaneous response ability, and is suitable for the measurement of high-frequency and large currents. However, in the conventional detection method, in a cross-connected grounding system, due to the possible differences in the direction and magnitude of the circulating currents in the inner and outer cores of the coaxial cable, the Rogowski coil will also be affected by vector superposition when setting the current; it is impossible to give a timely warning of risks such as excessive circulating current, resulting in an impact on the operation of power equipment.

[0059] As Figure 2 shown, in order to achieve the above object and solve the above problems, the present invention provides a method for detecting the circulating current of a coaxial cable with a cross-connected grounding method, including the following steps:

[0060] S1: Twist the flexible Rogowski coil into a forward loop and a reverse loop so that the forward loop and the reverse loop form an 8-shaped structure;

[0061] S2: Simultaneously sleeve the grounding wire of the phase to be measured and the main grounding wire inside the forward loop, and sleeve the grounding wire of another phase inside the reverse loop, wherein the head of the grounding wire of another phase is cross-connected with the tail of the grounding wire of the phase to be measured;

[0062] S3: Obtain the current detection value of the flexible Rogowski coil and calculate the actual circulating current of the grounding wire of the phase to be measured.

[0063] As Figure 1As shown in the figure, in this embodiment, the specific structure of the flexible Rogowski coil includes: a body, and a coil 1, a power switch button 2, a data hold button 3, a liquid crystal display screen 4, a voltage input socket 5, and an open coil knob 6 provided on the body; the coil 1 is fixed to the body through the open coil knob 6; the voltage input socket 5 is opened at the tail of the body and is used to supply power to the flexible Rogowski coil by connecting to a power source; the power switch button 2 and the data hold button 3 are symmetrically arranged. The power switch button 2 is used to turn on and off the flexible Rogowski coil, and the data hold button 3 is used to hold the current detected value and complete the reading of the value in a stable state; the liquid crystal display screen 4 is arranged on the handle of the body and is used to display the detected value. By displaying the detected value in real time through the liquid crystal display screen 4, the user experience and detection efficiency are further improved.

[0064] As Figure 4 shown, Figure 4 is the internal structure diagram of the cross-connected grounding box. It can be seen that the head of phase B is connected to the tail of phase A; the head of phase A is connected to the tail of phase C; the head of phase C is connected to the tail of phase B. Then the principle based on the above method is:

[0065]

[0066]

[0067] Among them, I a represents the detected value of phase A; I b represents the detected value of phase B; I c represents the detected value of phase C; I s represents the detected value of the total grounding current; A i represents the inner core current value of phase A; B i represents the inner core current value of phase B; C i represents the inner core current value of phase C; A0 represents the outer core current value of phase A; B0 represents the outer core current value of phase B; C0 represents the outer core current value of phase C.

[0068] There is a special relationship between the actual circulating current of the grounding wire of the phase to be measured and the total grounding current. The total grounding current is the sum of the inner core currents of each phase. The detected current of each phase is the vector sum of the inner core current and the outer core current of each phase, and the outer core current of each phase is equal to the reverse inner core current value of the cross-connected phase. Furthermore, the inner core current of each phase, that is, the actual circulating current value of each phase, can be obtained. Based on this principle, it is possible to conveniently and quickly detect the actual circulating current value of each phase accurately and reliably.

[0069] Combined with Figure 3 shown, in this embodiment, taking the grounding wire of phase A as an example, the current value I ais the vector sum of the current in the inner core of phase A and the current in the outer core of phase A; in the cross-connected mode, the current in the outer core of phase A is the value of the current in the inner core of phase C in the reverse direction; from this derivation, the value of the current in the inner core of phase A can be obtained, that is, the actual circulating current value of phase A is (total ground current detection value + phase A detection value - phase B detection value) ÷ 3. As Figure 5 shown, here, by screwing the flexible Rogowski coil into a forward loop and a reverse loop, the forward loop and the reverse loop form an 8-shaped structure ( Figure 5 the 8-shaped structure after the flexible Rogowski coil is screwed can be seen in Figure 6 and Figure 7 is the same), and the total ground wire and the ground current of phase A are sleeved in a loop in the forward direction, and the circulating current of phase B is sleeved in the reverse direction. In this way, by directly reading the first detection value of the current flexible Rogowski coil and dividing it by 3 according to the first detection value of the flexible Rogowski coil, the actual circulating current value of phase A can be obtained.

[0070] Similarly, as Figure 6 shown, when measuring the actual circulating current of phase B, the total ground wire and the ground current of phase B are sleeved in a loop in the forward direction, and the circulating current of phase C is sleeved in the reverse direction.

[0071] As Figure 7 shown, when measuring the actual circulating current of phase C, the total ground wire and the ground current of phase C are sleeved in a loop in the forward direction, and the circulating current of phase A is sleeved in the reverse direction.

[0072] It can be seen that a coaxial cable circulating current detection method with a cross-connected grounding method provided in this embodiment realizes the detection of the coaxial cable circulating current by designing a specific flexible Rogowski coil structure (the forward loop and the reverse loop form an 8 shape) and cleverly arranging the sleeving method of the ground wire during the detection process; this design not only improves the detection accuracy but also simplifies the operation process, making the cable circulating current detection in a complex environment more convenient and efficient.

[0073] Embodiment 2

[0074] This embodiment also provides a coaxial cable circulating current detection system with a cross-connected grounding method, which can implement the steps of the coaxial cable circulating current detection method provided in Embodiment 1. Specifically, it includes a detection value acquisition module for acquiring the current detection value of the flexible Rogowski coil; a circulating current calculation module for calculating the actual circulating current of the ground wire of the phase to be measured according to the current detection value of the flexible Rogowski coil; wherein, the current detection value of the flexible Rogowski coil is obtained in the following manner, specifically including: screwing the flexible Rogowski coil into a forward loop and a reverse loop, and the forward loop and the reverse loop form an 8-shaped structure; sleeving the ground wire of the phase to be measured and the total ground wire in the forward loop at the same time, and sleeving the ground wire of another phase in the reverse loop, wherein the head of the ground wire of another phase is cross-connected with the tail of the ground wire of the phase to be measured.

[0075] For the coaxial cable circulating current detection system adopting the cross - connected grounding method provided in this embodiment or the coaxial cable circulating current detection method adopting the cross - connected grounding method mentioned in Embodiment 1, during the detection of the circulating current in the cross - connected box, on - site staff can perform the circulating current test more conveniently, quickly, safely and accurately by using the above - mentioned system or method. It avoids the cumbersome operation of repeatedly opening and closing the circulating current box during the circulating current detection, reduces the safety risk of live work, and can accurately and reliably measure the value of the circulating current. Based on this, it can accurately judge whether the value of the circulating current exceeds the standard. After multiple reliable tests, the detection time is reduced from 26 minutes to 2 minutes, and the measurement error does not exceed 5% of the measured value. At the same time, using this method can improve the economic benefits of the entire industry, as specifically exemplified below:

[0076] It is evaluated mainly from three aspects: the reduction of workload, the reduction of potential safety hazards, and the economic benefits generated by the accurate measurement value of the circulating current.

[0077] I. Economic benefits generated by the reduction of workload

[0078] Annual cost savings=(26 - 2) / 60×1800×3×50.83 yuan = 109,800 yuan

[0079] Explanation: There are 200 groups of 220kV cross - connected boxes and 322 groups of 110kV cross - connected boxes in a certain city. According to the requirements of the operation and maintenance regulations, the circulating current should be measured at least 4 times for 220kV and 2 times for 110kV in one year. Plus special inspections and inspections of newly - put - into - operation equipment, there are more than 1800 times in total.

[0080] II. Economic benefits generated by the reduction of potential safety hazards:

[0081] Annual cost savings = 1800×0.1%×1,000,000 yuan = 1,800,000 yuan

[0082] Explanation: Since the detection of the circulating current in the box is a live operation and there is a risk of directly contacting a current of more than 50A, there may be an accident of serious electric shock. According to the "Regulations on the Reporting, Investigation and Handling of Production Safety Accidents", the economic loss is at least 1,000,000 yuan. According to the risk probability estimate, it occurs once every 1000 times.

[0083] III. Economic benefits generated based on the accurate measurement of the circulating current:

[0084] Annual cost savings = 1800×0.3%×350,000 yuan = 1,890,000 yuan

[0085] Explanation: Directly measuring the circulating current of the coaxial cable can only measure the value of the superimposed circulating current of two phases. Through the coaxial cable circulating current detection method proposed in this embodiment, the true value of the circulating current can be measured, so as to give an early warning of risks such as excessive circulating current to avoid affecting the operation of the equipment.

[0086] IV. Total: The total cost saved each year is: 1,098,000 + 18,000,000 + 18,900,000 = 37,998,000 yuan.

[0087] It can be seen that the coaxial cable circulating current detection method using the cross - connected grounding method provided by the present invention can generate huge economic benefits.

[0088] By using this method, the true value of the circulating current can be measured, ensuring the accuracy of the detection result, thereby warning against risks such as excessive circulating current to avoid affecting the operation of the equipment.

[0089] In summary, the present invention provides a coaxial cable circulating current detection method and system with a cross - connected grounding method, which has the following advantages compared with the existing detection methods:

[0090] First, by designing the flexible Rogowski coil to be screwed into an 8 - shaped structure of a forward loop and a reverse loop, and ingeniously sleeving the grounding wire of the phase to be measured, the main grounding wire, and the grounding wire of another phase into the forward loop and the reverse loop respectively, accurate detection of the coaxial cable circulating current in the cross - connected grounding method is realized. This method overcomes the problem that it is difficult to distinguish and accurately measure the circulating current of each phase in a complex grounding system in traditional detection methods, improving the accuracy and reliability of the detection. Secondly, specific detection methods and calculation formulas are given for the grounding wires of phase A, phase B, and phase C respectively, enabling operators to quickly obtain the actual circulating current value of each grounding wire according to a standardized process. This phase - by - phase detection method not only improves the detection efficiency but also ensures the accuracy and consistency of the data, providing strong support for subsequent cable maintenance and fault troubleshooting. In addition, the design of the flexible Rogowski coil also fully considers the user experience; by integrating components such as a coil, a power switch button, a data hold button, a liquid crystal display screen, a voltage input socket, and an open - coil knob, the detection tool is not only powerful but also easy to operate. Users can view the detection values in real time through the liquid crystal display screen and conveniently control the detection process through the power switch button and the data hold button, greatly improving the convenience and flexibility of the detection work. This method shows significant advantages in the detection of coaxial cable circulating current in the cross - connected grounding method, including improving detection accuracy, simplifying the operation process, and enhancing the user experience, providing strong technical guarantee for the safe and stable operation of the cable.

[0091] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0092] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its disclosed concept, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

[0093] Based on the further detailed description of the disclosure, it cannot be determined that the specific embodiments of the present invention are limited thereto. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope determined by the claims submitted for the present invention.

Claims

1. A method for detecting circulating current of a coaxial cable in a cross-connected grounding mode, characterized in that: include: The flexible Rogowski coil is twisted into a forward loop and a reverse loop, so that the forward loop and the reverse loop form an 8-shaped structure; The phase grounding wire to be tested and the main grounding wire are simultaneously sleeved in the forward loop, and the other phase grounding wire is sleeved in the reverse loop, wherein the head of the other phase grounding wire is cross-connected with the tail of the phase grounding wire to be tested; Obtain the current detection value of the flexible Rogowski coil and calculate the actual circulating current of the phase-to-ground wire to be tested; The specific calculation formula for the actual circulating current of the phase-to-ground wire to be measured is as follows: I a =A i +A o =A i -C i I b =B i +B o =B i -A i I c =C i +C o =C i -A i I s =A i +B i +C i Among them, I a Indicates the detection value of phase A; I b Indicates the detection value of phase B; I c Indicates the C phase detection value; I s Indicates the total ground current detection value; A i Indicates the current value of the core in phase A; B i Indicates the current value of the core in phase B; C i A0 represents the inner core current value of phase C; B0 represents the outer core current value of phase B; C0 represents the outer core current value of phase C.

2. The method for detecting circulating current of a coaxial cable in a cross-connected grounding mode according to claim 1, characterized in that: The detection method of the actual circulating current of the phase A grounding wire specifically includes: Put the A-phase grounding wire and the main grounding wire into the forward ring at the same time, and put the B-phase grounding wire into the reverse ring; The first detection value of the flexible Rogowski coil is obtained, and the actual circulating current of the A-phase grounding wire is calculated.

3. The method for detecting circulating current of a coaxial cable in a cross-connected grounding mode according to claim 2, characterized in that: The specific formula for the actual circulating current of phase A grounding wire is: The actual circulating current of the phase A grounding wire = the first detection value of the flexible Rogowski coil ÷ 3.

4. The method for detecting circulating current of a coaxial cable in a cross-connected grounding mode according to claim 1, characterized in that: The detection method of the actual circulating current of the phase B grounding wire specifically includes: Put the B-phase grounding wire and the main grounding wire into the forward ring at the same time, and put the C-phase grounding wire into the reverse ring; The second detection value of the flexible Rogowski coil is obtained, and the actual circulating current of the B-phase grounding wire is calculated.

5. The method for detecting circulating current of a coaxial cable in a cross-connected grounding mode according to claim 4, characterized in that: The specific formula for the actual circulating current of the phase B grounding wire is: The actual circulating current of the phase B grounding wire = the second detection value of the flexible Rogowski coil ÷ 3.

6. The method for detecting coaxial cable circulating current in a cross-connected grounding mode according to claim 1, characterized in that: The detection method of the actual circulating current of the C phase grounding wire specifically includes: Put the C-phase grounding wire and the main grounding wire into the forward ring at the same time, and put the A-phase grounding wire into the reverse ring; The third detection value of the flexible Rogowski coil is obtained, and the actual circulating current of the C-phase grounding wire is calculated.

7. The method for detecting coaxial cable circulating current in a cross-connected grounding mode according to claim 6, characterized in that: The specific formula for the actual circulating current of the C phase grounding wire is: The actual circulating current of the C phase grounding wire = the third detection value of the flexible Rogowski coil ÷ 3.

8. The method for detecting coaxial cable circulating current in a cross-connected grounding mode according to claim 1, characterized in that: The flexible Rogowski coil comprises a body, on which a coil (1), a power switch button (2), a data hold button (3), a liquid crystal display (4), a voltage input socket (5) and a coil opening knob (6) are arranged; The coil (1) is fixed to the body by opening the coil knob (6); The voltage input socket (5) is provided at the rear of the body and is used to supply power to the flexible Rogowski coil; The power switch button (2) and the data holding button (3) are symmetrically arranged, the power switch button (2) is used to disconnect the flexible Rogowski coil, and the data holding button (3) is used to hold the current detection value; The liquid crystal display screen (4) is arranged on the handle of the main body and is used to display the detected values.

9. A coaxial cable circulation detection system with cross-connected grounding, characterized in that: The steps for implementing the coaxial cable circulating current detection method of the cross-connection grounding method according to any one of claims 1 to 8 include: A detection value acquisition module is used to obtain the current detection value of the flexible Rogowski coil; A circulating current calculation module, used to calculate the actual circulating current of the phase-to-ground wire to be tested according to the current detection value of the flexible Rogowski coil; The current detection value of the flexible Rogowski coil is obtained by the following methods, including: The flexible Rogowski coil is screwed into a forward ring and a reverse ring, wherein the forward ring and the reverse ring form an 8-shaped structure; the phase grounding wire to be tested and the main grounding wire are simultaneously sleeved in the forward ring, and the other phase grounding wire is sleeved in the reverse ring, wherein the head of the other phase grounding wire is cross-connected with the tail of the phase grounding wire to be tested.

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