A roebel coil applied to distribution network traveling wave current acquisition

Abstract

A Rogowski coil applied to distribution network traveling wave current acquisition belongs to the field of traveling wave current acquisition equipment. It comprises a ring-shaped winding framework (2), a secondary side coil (3) is wound on the winding framework (2), and a primary side coil (4) is further arranged at the winding framework (2), characterized in that a magnetic core (6) is arranged in the winding framework (2), at least one opening is arranged on the circumference of the magnetic core (6), and the winding angle of the secondary side coil (3) along the circumference of the winding framework (2) is less than 360°. In the Rogowski coil applied to distribution network traveling wave current acquisition, at least one opening is arranged on the circumference of the magnetic core, so that the magnetic core meets the mutual inductance coefficient of the distribution network traveling wave current, and the magnetic saturation during measurement is avoided, meanwhile, the two coil joints of the secondary side coil do not overlap on the surface of the winding framework, which is more helpful to meet the requirement of inter-turn capacitance and further meet the frequency bandwidth during sampling.

Description

Technical Field

[0001] A Rogowski coil for collecting traveling wave current in distribution networks belongs to the field of traveling wave current acquisition equipment. Background Technology

[0002] With the rapid development of the power industry, it has shifted from traditional power distribution to automated power distribution. Monitoring the operational status of primary equipment along overhead cables is crucial, ensuring the reliability of power supply in automated distribution systems. This significantly reduces the workload of line inspections and saves on engineering maintenance costs. It also facilitates the rapid identification of fault points, enabling timely handling of on-site problems and rapid restoration of power.

[0003] When monitoring the operating status of overhead cables, traveling wave current signals are crucial parameters. In existing technologies, using Rogowski coils for power frequency current acquisition is a common method. However, the traveling wave current signal in distribution networks differs significantly from that in power transmission and transformation networks. Specifically, the full-scale values ​​of the distribution network traveling wave current signal and the power frequency current signal differ considerably. For example, the full-scale current on the primary side of an overhead line in a distribution network is approximately 100A, while the full-scale value of the power frequency current signal is much larger, around 600A. This leads to the problem that traditional Rogowski coils, due to limitations in mutual inductance and core bandwidth, are prone to power frequency magnetic saturation when directly acquiring distribution network traveling wave currents, making acquisition difficult. Therefore, designing a Rogowski coil capable of acquiring distribution network traveling wave currents has become a pressing issue in this field. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a Rogowski coil for distribution network traveling wave current acquisition that enables the magnetic core to meet the mutual inductance coefficient of the distribution network traveling wave current, avoid magnetic saturation, and at the same time help the inter-turn capacitance meet the requirements, further satisfying the bandwidth during sampling.

[0005] The technical solution adopted by this utility model to solve its technical problem is as follows: the Rogowski coil used for collecting traveling wave current in distribution networks includes an annular winding frame, a secondary coil wound on the winding frame, and a primary coil that is mutually inductive with the secondary coil at the winding frame. The feature is that a magnetic core is provided inside the winding frame, at least one opening is provided around the periphery of the magnetic core, and the winding angle of the secondary coil along the periphery of the winding frame is less than 360°.

[0006] Preferably, the magnetic core includes two symmetrically arranged magnetic core units, which are arranged opposite to each other in the winding frame, and an opening is formed between the ports on the same side of the two magnetic core units.

[0007] Preferably, the width of the opening is 0.8mm to 1.2mm.

[0008] Preferably, the width of the opening is 1 mm.

[0009] Preferably, the primary coil passes through the center hole of the winding bobbin or is evenly wound on the winding bobbin.

[0010] Preferably, the winding frame includes a housing, and the magnetic core is located inside the housing.

[0011] Preferably, the number of turns of the secondary coil is 200 to 400.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] In the Rogowski coil used for distribution network traveling wave current acquisition in this application, at least one opening is provided around the periphery of the magnetic core. This allows the magnetic core to meet the mutual inductance coefficient of the distribution network traveling wave current, avoid magnetic saturation during measurement, and further help the inter-turn capacitance meet the requirements, thereby satisfying the bandwidth during sampling and enabling the acquisition of distribution network traveling wave current.

[0014] In the Rogowski coil used for distribution network traveling wave current acquisition in this application, the width of the opening is 0.8mm~1.2mm, preferably 1.0mm, which ensures a high magnetic flux density and prevents distortion of the power frequency current signal waveform caused by magnetic saturation.

[0015] The two coil terminals of the secondary coil do not overlap on the surface of the winding frame, which helps to meet the requirements of inter-turn capacitance and prevents severe attenuation of high-frequency signals. At the same time, setting the number of turns of the secondary coil to 200~400 turns helps to meet the requirements of equivalent inductance and further helps to meet the bandwidth requirements during sampling. Attached Figure Description

[0016] Figure 1 This is a front view of a Rogowski coil used for collecting traveling wave current in a distribution network.

[0017] Figure 2 This is a right view of the magnetic core in a Rogowski coil used for collecting traveling wave current in a distribution network.

[0018] Figure 3 for Figure 2 Sectional view along the AA direction.

[0019] Figure 4 This is the equivalent circuit diagram of a Rogowski coil used for traveling wave current acquisition in distribution networks.

[0020] The components are: 1. Coil connector; 2. Winding frame; 3. Secondary coil; 4. Primary coil; 5. Housing; 6. Magnetic core. Detailed Implementation

[0021] Figures 1-4 This is the preferred embodiment of the present invention, which is described below in conjunction with the appendix. Figures 1-4 The present invention will be further described below.

[0022] like Figure 1 As shown, a Rogowski coil (hereinafter referred to as this Rogowski coil) for collecting traveling wave current in a distribution network includes a circular winding frame 2, on which a secondary coil 3 is wound. A primary coil 4 is also provided. When the primary coil 4 has one turn, it can pass directly through the central hole of the winding frame 2. If the primary coil 4 has multiple turns, it is also wound on the winding frame 2, and in this case, the primary coil 4 is symmetrically or evenly wound on the winding frame 2.

[0023] like Figures 2-3 As shown, the winding frame 2 includes a housing 5 and a magnetic core 6 disposed within the housing 5. The magnetic core 6 includes magnetic core units symmetrically disposed at both ends of the housing 5, and each magnetic core unit at both ends is semi-circular. The housing 5 can be a one-piece structure or a structure in which two sections are joined together and fixed as one piece.

[0024] A groove for accommodating the magnetic core 6 is provided inside the housing 5. The two magnetic core segments are arranged opposite each other inside the housing 5, and after the two magnetic core segments are fixed inside the housing 5, an opening is formed between the ports on the same side of the two magnetic core segments. In this Rogowski coil, the width of the opening is 0.8mm to 1.2mm, preferably 1.0mm, which ensures a high magnetic flux and prevents distortion of the power frequency current signal waveform caused by magnetic saturation.

[0025] The magnetic core 6 is made of a microcrystalline material known in the art, and is magnetized using conventional methods in the art to improve the mutual inductance coefficient of the Rogowski coil core 6, making the relative permeability of the core 6 approximately 20,000. Setting the relative permeability of the core 6 to 20,000 avoids magnetic saturation problems while also meeting the mutual inductance coefficient required between the primary coil 4 and the secondary coil 3 in the Rogowski coil. This is more suitable for the characteristics of the small amplitude of the traveling wave current signal in the distribution network line and is more conducive to the acquisition of the traveling wave current signal.

[0026] Combination Figure 4 The equivalent circuit of the Rogowski coil shown has coil L1 (primary coil 4) and coil L2 (secondary coil 3) mutually inducted with a mutual inductance coefficient of M. One end of coil L2 is connected in series with the equivalent inductance L0 and the internal resistance R0, and is simultaneously connected to one end of the inter-turn capacitance C0 and one end of the load R1. The other end of coil L2 is simultaneously connected to the other end of the inter-turn capacitance C0 and the other end of the load R1.

[0027] To ensure that this Rogowski coil can achieve a sampling range of 5kHz to 500kHz when acquiring traveling wave current in the distribution network, the bandwidth of the transformer is adjusted by modifying the self-inductance of the equivalent inductance L0, the resistance of the internal resistance R0, and the capacitance of the inter-turn capacitance C0. Specifically, the number of turns of the secondary coil is adjusted to 200-400 turns, so that the self-inductance of the equivalent inductance L0 is approximately 10mH; the resistance of the internal resistance R0 is approximately 10Ω; and the capacitance of the inter-turn capacitance C0 is set to 40pF to prevent severe attenuation of high-frequency signals.

[0028] To ensure the inter-turn capacitance C0 is approximately 40pF, when winding the secondary coil 3 onto the surface of the winding frame 2, the two coil joints 1 of the secondary coil 3 should not overlap on the circumference of the winding frame 2. That is, when winding the secondary coil 3, after identifying one coil joint 1 as the starting point and beginning winding along the circumference of the winding frame 2 from that starting point, the coil joint 1 at the end point should not cross over the coil joint 1 at the starting point. If, before winding, it is confirmed through the wire diameter and the circumference of the winding frame 2 that a single layer cannot achieve the preset number of turns, multiple layers can be wound radially along the winding frame 2 during the circumference winding process to ensure that the two coil joints 1 do not overlap on the circumference of the winding frame 2.

[0029] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from its technical solution shall still fall within the protection scope of this utility model.

Claims

1. A Rogowski coil applied to distribution network traveling wave current acquisition, comprising a ring-shaped winding skeleton (2), a secondary side coil (3) is wound on the winding skeleton (2), and a primary side coil (4) is further arranged at the winding skeleton (2) and is mutually inductive with the secondary side coil (3), characterized in that: A magnetic core (6) is provided inside the winding frame (2), and at least one opening is provided around the magnetic core (6), and the winding angle of the secondary coil (3) along the circumference of the winding frame (2) is less than 360°.

2. The Rogowski coil for collecting traveling wave current in network configuration according to claim 1, characterized in that: The magnetic core (6) includes two symmetrically arranged magnetic core units. The two magnetic core units are arranged opposite to each other in the winding frame (2), and an opening is formed between the ports on the same side of the two magnetic core units.

3. The Rogowski coil for network traveling wave current acquisition according to claim 1 or 2, characterized in that: The width of the opening is 0.8mm~1.2mm.

4. The Rogowski coil for network traveling wave current acquisition of claim 3, wherein: The width of the opening is 1mm.

5. The Rogowski coil for power network traveling wave current acquisition according to claim 1, characterized in that: The primary coil (4) passes through the center hole of the winding skeleton (2) or is evenly wound on the winding skeleton (2).

6. The Rogowski coil for power network traveling wave current acquisition of claim 1, wherein: The winding frame (2) includes a housing (5) and a magnetic core (6) located inside the housing (5).

7. The Rogowski coil for power network traveling wave current acquisition according to claim 1, characterized in that: The secondary coil (3) has 200 to 400 turns.

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