CN102436897A - Flexible Rogowski coil used for detecting direct-current system short-circuit current and method for designing same - Google Patents

Abstract

Translated fromChinese

一种用于直流系统短路电流检测的柔性罗氏线圈及其设计方法，该线圈包括均匀绕制在带有开口的圆环形柔性骨架上的线圈及回线，在线圈及回线外套装有外层绝缘套管，圆环形柔性骨架的开口上安装有与线圈及回线相连接的插入式接口，线圈出线经插入式接口的孔引出后与取样电阻模块相连，取样电阻模块引出信号与后级积分电路相连接。本发明所采用的罗氏线圈回线绕线工艺，回线和线圈绕线本身由一条线构成。罗氏线圈首末端通过插入式接口进行连接，采用该工艺能够极大程度的提高罗氏线圈的机械寿命，可靠性高同时便于拆卸和安装；所述的一种用于直流系统短路电流检测的罗氏线圈的设计方法，能够结合直流系统短路的具体情况和现场工况。

A flexible Rogowski coil for DC system short-circuit current detection and its design method. The coil includes a coil and a return wire uniformly wound on a circular flexible frame with an opening, and an outer coil and a return wire are sheathed on the coil and the return wire. The opening of the circular flexible frame is equipped with a plug-in interface connected to the coil and the return line. The coil outlet is connected to the sampling resistor module after being drawn out through the hole of the plug-in interface. The signal from the sampling resistor module is connected to the rear stage integration circuit connected. In the Rogowski coil loop winding process adopted in the present invention, the loop and coil winding itself are composed of one wire. The Rogowski coil head and end are connected through a plug-in interface. This process can greatly improve the mechanical life of the Rogowski coil, has high reliability and is easy to disassemble and install; the described Rogowski coil for short-circuit current detection in DC systems The design method can be combined with the specific situation of the short circuit of the DC system and the working conditions of the site.

Description

Translated fromChinese

一种用于直流系统短路电流检测的柔性罗氏线圈及其设计方法A flexible Rogowski coil for DC system short-circuit current detection and its design method

技术领域technical field

本发明属于电子式电流互感器，具体涉及一种用于直流系统短路电流测量的罗氏线圈及其设计方法，。The invention belongs to electronic current transformers, and in particular relates to a Rogowski coil for short-circuit current measurement in a DC system and a design method thereof.

背景技术Background technique

为了在直流电力系统发生短路故障时能够快速的检测到故障，同时为了更方便的与数字式智能单元相连接以实现数字化测量与保护，基于电磁感应原理的罗氏线圈被广泛应用。In order to quickly detect the fault when a short-circuit fault occurs in the DC power system, and to connect with the digital intelligent unit more conveniently to realize digital measurement and protection, Rogowski coils based on the principle of electromagnetic induction are widely used.

与其他的暂态电流检测方法相比较，空心式罗氏线圈所采用的骨架为非铁磁性绝缘材料，由于其不含铁心，理论上不存在磁饱和问题，几乎不受被测电流大小的限制，非常适合于对大电流的测量。Compared with other transient current detection methods, the skeleton of the air-core Rogowski coil is a non-ferromagnetic insulating material. Since it does not contain an iron core, there is no magnetic saturation problem in theory, and it is almost not limited by the magnitude of the measured current. Very suitable for the measurement of large currents.

在针对暂态大电流的测量中，以往的基于罗氏线圈的测量，一方面工艺上的性能仍有待改进，以往的空心式罗氏线圈，由于绕线所采用漆包线较细，当罗氏线圈受到外力作用时，漆包线容易被拉断，造成罗氏线圈产品的故障；另一方面，缺少一种流程化的设计方法做为指导，以更好的与数字化智能单元相连接以实现数字化测量与保护。In the measurement of transient large currents, the previous measurement based on Rogowski coils, on the one hand, still needs to be improved in terms of technological performance. The previous hollow Rogowski coils, because the enameled wire used for winding is relatively thin, when the Rogowski coils are subjected to external forces At the same time, the enameled wire is easily broken, causing the failure of Rogowski coil products; on the other hand, there is a lack of a process design method as a guide to better connect with the digital intelligent unit to achieve digital measurement and protection.

发明内容Contents of the invention

本发明的目的在于提供一种能够将高幅值暂态电流信号转换成可与后级数字化智能单元相连接的高精度的用于直流系统短路电流检测的柔性罗氏线圈及其设计方法。The purpose of the present invention is to provide a high-precision flexible Rogowski coil for DC system short-circuit current detection and its design method, which can convert high-amplitude transient current signals into a high-precision digital intelligent unit that can be connected to the subsequent stage.

为达到上述目的，本发明的柔性罗氏线圈包括均匀绕制在带有开口的圆环形柔性骨架上的线圈及回线，在线圈及回线外套装有外层绝缘套管，圆环形柔性骨架的开口上安装有与线圈及回线相连接的插入式接口，线圈出线经插入式接口的孔引出后与取样电阻模块相连，取样电阻模块引出信号与后级积分电路相连接。In order to achieve the above object, the flexible Rogowski coil of the present invention includes a coil and a loop uniformly wound on a circular flexible skeleton with an opening, and an outer insulating sleeve is placed on the coil and the loop, and the circular flexible The opening of the frame is equipped with a plug-in interface connected to the coil and the return line. The coil outlet is connected to the sampling resistor module after being drawn out through the hole of the plug-in interface, and the signal drawn from the sampling resistor module is connected to the subsequent integration circuit.

所述的取样电阻模块包括经插入式接口与线圈出线相连接的取样电阻，所述取样电阻的两端同时与保护外壳上的BNC插座相连接。The sampling resistance module includes a sampling resistance connected to the coil outlet through a plug-in interface, and both ends of the sampling resistance are connected to the BNC socket on the protective shell at the same time.

所述的柔性骨架由柔性绝缘材料构成，且该柔性骨架的几何中间部分开设有使回线通过的通孔。The flexible frame is made of flexible insulating material, and a through hole is opened in the geometrically middle part of the flexible frame for the return wire to pass through.

所述的线圈及回线自柔性骨架的一端穿入柔性骨架的通孔，由另一端引出后以单层方式均匀的绕制在柔性骨架上，且在穿过柔性骨架通孔的回线上套装有起紧固和保护作用的聚四氟乙烯绝缘材料。The coils and loops are inserted into the through hole of the flexible frame from one end of the flexible frame, and are evenly wound on the flexible frame in a single layer after being led out from the other end, and on the loop passing through the through hole of the flexible frame The suit has Teflon insulation for fastening and protection.

所述的插入式接口的两端为凹型，插入式接口中间设有螺纹凹槽与取样电阻模块螺纹连接。Both ends of the plug-in interface are concave, and a threaded groove is provided in the middle of the plug-in interface to be threadedly connected to the sampling resistance module.

本发明的设计方法如下：Design method of the present invention is as follows:

1)先根据对直流系统呈指数变化的短路电流的频谱分析，确定罗氏线圈的频率下限，根据所得的频率下限确定外积分电路的时间常数；1) First, determine the lower limit of the frequency of the Rogowski coil according to the frequency spectrum analysis of the exponentially changing short-circuit current of the DC system, and determine the time constant of the outer integrating circuit according to the lower limit of the frequency obtained;

2)然后根据载流母线的尺寸，在保证绝缘条件满足的条件下确定罗氏线圈柔性骨架的尺寸并根据被测电流峰值和外积分电路的时间常数确定罗氏线圈的互感；2) Then, according to the size of the current-carrying busbar, the size of the flexible skeleton of the Rogowski coil is determined under the condition that the insulation condition is satisfied, and the mutual inductance of the Rogowski coil is determined according to the peak value of the measured current and the time constant of the external integration circuit;

3)首先判断单层线圈及回线是否满足罗氏线圈互感大小的要求，如果不能满足，则改变柔性骨架截面直径使单层线圈及回线满足互感大小的要求；3) First judge whether the single-layer coil and loop meet the requirements of the mutual inductance of the Rogowski coil, if not, change the cross-sectional diameter of the flexible skeleton so that the single-layer coil and loop meet the requirements of the mutual inductance;

4)如果满足罗氏线圈互感的要求则制作罗氏线圈并进行参数的测量，根据最佳匹配确定外接电阻的大小。4) If the requirements of the mutual inductance of the Rogowski coil are met, the Rogowski coil is made and the parameters are measured, and the size of the external resistance is determined according to the best match.

本发明所涉及的柔性空心式罗氏线圈，对罗氏线圈的结构工艺进行改进，在保证测量精度的前提下，提高了罗氏线圈的机械寿命。同时，提出了一种通用的设计方法，用于直流电力系统短路条件下电流的检测。The flexible hollow Rogowski coil involved in the present invention improves the structural process of the Rogowski coil, and improves the mechanical life of the Rogowski coil on the premise of ensuring measurement accuracy. At the same time, a general design method is proposed for current detection under short-circuit conditions in DC power systems.

本发明所提出的用于直流系统短路电流检测的柔性罗氏线圈，骨架材料应选取温度特性较好的材料，采用硅橡胶作为罗氏线圈的骨架材料。硅橡胶具有耐高温、耐高压、防水、防腐等性能，可以工作在-60℃～+180℃，具有良好的柔韧性，是柔性罗氏线圈骨架的理想材料。For the flexible Rogowski coil used in the detection of short-circuit current in the DC system proposed by the present invention, the skeleton material should be selected from materials with better temperature characteristics, and silicon rubber is used as the skeleton material of the Rogowski coil. Silicone rubber has the properties of high temperature resistance, high pressure resistance, waterproof, anti-corrosion, etc. It can work at -60°C ~ +180°C, has good flexibility, and is an ideal material for flexible Rogowski coil skeletons.

以往关于柔性罗氏线圈的回线，多是利用电缆本身芯线作为罗氏线圈回线，安装虽然简单，但是需要将芯线和漆包线进行焊接，这种工艺所带来的缺点就是将会增大线圈本身的自分布电容，降低线圈本身的频带宽度，影响测量精度。本发明所采用的罗氏线圈回线绕线工艺，回线和线圈绕线本身由一条线构成，具体是将硅橡胶电缆内芯抽掉，电缆内部套入聚四氟乙烯材料，作为漆包线的保护套管。所述的聚四氟乙烯绝缘材料套在漆包线的外层起紧固和防止断裂的保护作用，这种工艺制作的线圈结构紧凑，牢固性好，同时能保证很高的测量精度，适合工业生产使用。In the past, the return wire of the flexible Rogowski coil mostly used the core wire of the cable itself as the return wire of the Rogowski coil. Although the installation is simple, it needs to weld the core wire and the enameled wire. The disadvantage of this process is that it will increase the size of the coil. The self-distributed capacitance itself reduces the bandwidth of the coil itself and affects the measurement accuracy. In the Rogowski coil loop winding process adopted in the present invention, the loop wire and the coil winding itself are composed of a single wire, specifically, the inner core of the silicone rubber cable is removed, and polytetrafluoroethylene material is inserted inside the cable as a protection for the enameled wire. casing. The polytetrafluoroethylene insulating material is covered on the outer layer of the enameled wire to protect it from fastening and preventing breakage. The coil made by this process has a compact structure and good firmness, and at the same time can ensure high measurement accuracy, which is suitable for industrial production use.

所述的罗氏线圈绕线采用均匀密绕方式，这种绕线方式可以保证很好的抗干扰性能以及极大程度减小了绕线不均匀所带来的测量误差，同时密绕方式可以增大线圈的互感，提高了测量的信噪比。The Rogowski coil is wound in a uniform and dense manner, which can ensure good anti-interference performance and greatly reduce the measurement error caused by uneven winding. At the same time, the dense winding method can increase the The mutual inductance of the large coil improves the signal-to-noise ratio of the measurement.

附图说明Description of drawings

图1是罗氏线圈传感头的结构示意图；Fig. 1 is a structural schematic diagram of a Rogowski coil sensing head;

图2是罗氏线圈传感头取样电阻模块的结构示意图；Fig. 2 is a structural schematic diagram of a Rogowski coil sensing head sampling resistor module;

图3是罗氏线圈外积分电路的结构图；Fig. 3 is the structural diagram of the integrating circuit outside the Rogowski coil;

图4是外积分型罗氏线圈的设计流程图。Fig. 4 is the design flow chart of the outer integral Rogowski coil.

具体实施方式Detailed ways

下面结合附图做进一步详细说明。Further details will be described below in conjunction with the accompanying drawings.

参见图1，本发明包括柔性骨架2、线圈及回线1、外层绝缘套管3、取样电阻模块4及插入式接口5；所述线圈均匀绕制在柔性骨架2上，线圈回线埋置于柔性骨架2的几何中心，绕线两端通过插入式接口5经取样电阻模块4后引出；整个罗氏线圈构成一开口的圆环，首末端在使用时通过插入式接口5进行连接，罗氏线圈引出信号与后级积分电路相连接。本发明所采用的罗氏线圈回线绕线工艺，回线和线圈绕线本身由一条线构成，具体是将硅橡胶电缆内芯抽掉，电缆内部套入聚四氟乙烯材料，作为漆包线的保护套管。所述的聚四氟乙烯绝缘材料套在漆包线的外层起紧固和防止断裂的保护作用，这种工艺制作的线圈结构紧凑，牢固性好，同时能保证很高的测量精度，适合工业生产使用。Referring to Fig. 1, the present invention includes aflexible skeleton 2, a coil and a loop 1, an outerinsulating sleeve 3, asampling resistance module 4 and a plug-in interface 5; the coil is evenly wound on theflexible skeleton 2, and the coil loop is buried Placed at the geometric center of theflexible skeleton 2, the two ends of the winding wire are drawn out after passing through thesampling resistor module 4 through the plug-in interface 5; The signal drawn from the coil is connected with the integration circuit of the rear stage. In the Rogowski coil loop winding process adopted in the present invention, the loop wire and the coil winding itself are composed of one wire, specifically, the inner core of the silicone rubber cable is removed, and the inside of the cable is covered with polytetrafluoroethylene material as a protection for the enameled wire. casing. The polytetrafluoroethylene insulating material is covered on the outer layer of the enameled wire to protect it from fastening and preventing breakage. The coil made by this process has a compact structure and good firmness, and at the same time can ensure high measurement accuracy, which is suitable for industrial production use.

参见图2，线圈引出线经插入式接口5的孔引出后与取样电阻模块4中的取样电阻8焊接连接。取样电阻两端同时与保护外壳7上的BNC插座6焊接连接。BNC插座与屏蔽双绞线相连接，采用屏蔽层对削弱静电耦合和电磁耦合有很明显的作用，同时屏蔽层应保证良好接地。双绞线则通过减小来回线的感应面积来降低感应干扰。Referring to FIG. 2 , the lead wire of the coil is led out through the hole of the plug-in interface 5 and then welded to thesampling resistor 8 in thesampling resistor module 4 . Both ends of the sampling resistor are soldered to theBNC socket 6 on theprotective shell 7 at the same time. The BNC socket is connected to the shielded twisted pair, and the use of the shielding layer has a significant effect on weakening the electrostatic coupling and electromagnetic coupling, and the shielding layer should be well grounded. Twisted pair wires reduce inductive interference by reducing the induction area of the round-trip wires.

参见图3，外接积分电路采用有源积分，包括四个部分：即电压跟随电路、外积分电路、滤波电路、放大电路。Referring to Figure 3, the external integral circuit adopts active integral, which includes four parts: voltage follower circuit, external integral circuit, filter circuit, and amplifier circuit.

参见图4，本发明的外积分型的罗氏线圈的设计流程如下：Referring to Fig. 4, the design process of the Rogowski coil of the outer integral type of the present invention is as follows:

1)先根据对直流系统呈指数变化的短路电流的频谱分析，根据信号频谱特性中能量的分布特性确定罗氏线圈的频率下限，以保证能准确的反映原始信号的频率特性。由于外积分式罗氏线圈的频率下限决定于外积分电路的时间常数，即

(f_l为罗氏线圈的频率下限τ为外积分电路的时间常数)，故根据所得的频率下限即可确定外积分电路的时间常数；1) First, according to the frequency spectrum analysis of the exponentially changing short-circuit current of the DC system, the lower limit of the frequency of the Rogowski coil is determined according to the energy distribution characteristics in the signal spectrum characteristics, so as to ensure that the frequency characteristics of the original signal can be accurately reflected. Since the lower limit of the frequency of the external integrating Rogowski coil is determined by the time constant of the external integrating circuit, that is

(f_l is the frequency lower limit τ of the Rogowski coil and is the time constant of the outer integrating circuit), so the time constant of the outer integrating circuit can be determined according to the obtained frequency lower limit;

2)然后根据载流母线的尺寸，在保证绝缘条件满足的条件下，即保证系统电压在设定距离下空气不被击穿，确定罗氏线圈柔性骨架的尺寸并根据被测电流峰值和外积分电路的时间常数确定罗氏线圈的互感，即根据公式

(其中M为罗氏线圈的互感，u₀为根据系统确定的测量输出电压的最大值，一般为10V或5V等，τ为外积分电路的时间常数，I为所测量电流的峰值)；2) Then, according to the size of the current-carrying busbar, under the condition that the insulation conditions are satisfied, that is, to ensure that the system voltage is not broken down by the air at a set distance, determine the size of the flexible skeleton of the Rogowski coil and according to the peak value of the measured current and the external integral The time constant of the circuit determines the mutual inductance of the Rogowski coil, that is, according to the formula

(wherein M is the mutual inductance of the Rogowski coil,_u0 is the maximum value of the measured output voltage determined according to the system, generally 10V or 5V, etc., τ is the time constant of the external integration circuit, and I is the peak value of the measured current);

3)首先判断线圈及回线单层绕线方式是否满足罗氏线圈互感大小的要求，即判断假设在单层绕线且均匀密绕方式下是否能满足互感要求，这一点可以根据公式互感

(其中μ₀为空气的磁导率，值为4π×10^-7，N为单层绕线方式下的绕线匝数，D为罗氏线圈的直径，d为柔性骨架截面直径)得出，如果不能满足，则改变柔性骨架截面直径使单层线圈及回线满足互感大小的要求；3) First judge whether the single-layer winding method of the coil and the return wire meets the requirements of the mutual inductance of the Rogowski coil, that is, judge whether the mutual inductance requirements can be met under the assumption that the single-layer winding and uniform dense winding method can be used. This can be based on the formula mutual inductance

(where μ₀ is the magnetic permeability of air, the value is 4π×10^-7 , N is the number of winding turns in the single-layer winding mode, D is the diameter of the Rogowski coil, and d is the cross-sectional diameter of the flexible skeleton), If it cannot be met, change the cross-sectional diameter of the flexible skeleton to make the single-layer coil and loop meet the requirements of mutual inductance;

4)如果满足罗氏线圈互感的要求则制作罗氏线圈并进行参数线圈自感L_c、线圈分布电容C_c及线圈内阻R_c的测量，根据最佳匹配，即

确定外接电阻R_s的大小。4) If the requirement of Rogowski coil mutual inductance is met, Rogowski coils are made and the parameters coil self-inductance L_c , coil distributed capacitance C_c and coil internal resistance R_c are measured. According to the best matching, that is

Determine the size of the external resistor R_s .

Claims (6)

1. one kind is used for the flexible Luo-coil that the direct current system short circuit current detects; It is characterized in that: comprise the coil and the loop line (1) that evenly are wound on the annular flexible back bone (2) that has opening; Outside coil and loop line (1), be set with outer layer insulation sleeve pipe (3); The plug-in type interface (5) that is connected with coil and loop line (1) is installed on the opening of annular flexible back bone (2); The coil outlet links to each other with sample resistance module (4) after draw in the hole of plug-in type interface (5), and sample resistance module (4) is drawn signal and is connected with back level integrating circuit.

2. the flexible Luo-coil that is used for the detection of direct current system short circuit current according to claim 1; It is characterized in that: described sample resistance module (4) comprises the sample resistance (8) that is connected with the coil outlet through plug-in type interface (5), and the two ends while of said sample resistance (8) is connected with the BNC socket (6) on the protecting sheathing (7).

3. the flexible Luo-coil that is used for the detection of direct current system short circuit current according to claim 1; It is characterized in that: described flexible back bone (2) is made up of flexible insulating material, and how much mid portions of this flexible back bone (2) offer the through hole that loop line is passed through.

4. the flexible Luo-coil that is used for the detection of direct current system short circuit current according to claim 1; It is characterized in that: described coil and loop line (1) penetrate the through hole of flexible back bone (2) from an end of flexible back bone (2); Draw the back by the other end and be wound on uniformly on the flexible back bone (2), and on the loop line that passes the flexible back bone through hole, be set with fastening and Teflom Insulation Material protective effect with the individual layer mode.

5. the flexible Luo-coil that is used for the detection of direct current system short circuit current according to claim 1; It is characterized in that: the two ends of described plug-in type interface (5) are matrix, are provided with thread groove in the middle of the plug-in type interface (5) and are threaded with sample resistance module (4).

6. method for designing that is used for the flexible Luo-coil that the direct current system short circuit current detects is characterized in that:

1) earlier according to the spectrum analysis that direct current system is the short circuit current of index variation, confirms the lower-frequency limit of Luo-coil, confirm outer integration circuit time constant according to the lower-frequency limit of gained;

2) then according to the size of current carrying bus, under guaranteeing the condition that the insulation condition satisfies, confirm the Luo-coil flexible back bone size and according to tested current peak with outside integration circuit time constant confirm the mutual inductance of Luo-coil;

3) judge at first whether single layer coil and loop line satisfy the requirement of Luo-coil mutual inductance size,, then change the flexible back bone diameter of section and make single layer coil and loop line satisfy the requirement of mutual inductance size if can not satisfy;

4) if satisfy the requirement of Luo-coil mutual inductance then make the go forward side by side measurement of line parameter of Luo-coil, confirm the size of outer meeting resistance according to optimum Match.

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