CN103245877A - Method for ranging single-phase earth fault of line by using single-end electric quantity - Google Patents

本发明公开了一种利用单端电气量实现线路单相接地故障测距方法。本发明方法测量输电线路保护安装处的故障相电压、故障相负序电流、故障相电流和零序电流，计算故障相电压与故障相负序电流的比值的虚部，计算单位长度输电线路电压降与故障相负序电流的比值的虚部，利用故障相电压与故障相负序电流的比值的虚部除以单位长度输电线路电压降与故障相负序电流的比值的虚部，得到输电线路保护安装处到单相接地故障点的故障距离。本发明方法利用单端电气量实现了输电线路单相接地故障距离的精确测量，克服了过渡电阻和负荷电流对故障距离测量精度的影响，测距原理简单，程序实现容易，运算量少，测距速度快，实时性强。

The invention discloses a single-phase grounding fault distance measurement method for a line by using a single-end electrical quantity. The method of the invention measures the fault phase voltage, fault phase negative sequence current, fault phase current and zero sequence current at the protection installation place of the transmission line, calculates the imaginary part of the ratio of the fault phase voltage to the fault phase negative sequence current, and calculates the unit length transmission line voltage The imaginary part of the ratio of the fault phase voltage drop to the fault phase negative sequence current is divided by the imaginary part of the ratio of the fault phase voltage drop to the fault phase negative sequence current by the ratio of the unit length transmission line voltage drop to the fault phase negative sequence current to obtain the transmission The fault distance from the line protection installation to the single-phase ground fault point. The method of the invention realizes the precise measurement of the single-phase grounding fault distance of the transmission line by using the single-ended electrical quantity, overcomes the influence of the transition resistance and the load current on the measurement accuracy of the fault distance, has simple principle of distance measurement, easy program realization, less calculation amount, and easy measurement. The distance is fast and the real-time performance is strong.

利用单端电气量实现线路单相接地故障测距方法Using Single-End Electrical Quantity to Realize the Distance Measurement Method of Line Single-phase Grounding Fault

技术领域 technical field

本发明涉及电力系统继电保护技术领域，具体地说是涉及一种利用单端电气量实现线路单相接地故障测距方法。The invention relates to the technical field of electric power system relay protection, in particular to a single-phase grounding fault distance measurement method of a line by using single-ended electrical quantities.

背景技术 Background technique

输电线路单端故障测距方法仅利用输电线路一端电气量进行故障定位，无须通讯和数据同步设备，运行费用低且算法稳定，在输电线路中获得广泛应用。The single-end fault location method of transmission lines only uses the electrical quantity at one end of the transmission line for fault location, does not require communication and data synchronization equipment, has low operating costs and stable algorithms, and has been widely used in transmission lines.

单端故障测距方法主要分为行波法和阻抗法。行波法利用故障暂态行波的传送性质进行单端故障测距，精度高，不受运行方式、过度电阻等影响，但对采样率要求很高，需要专门的录波装置，应用成本高。阻抗法利用故障后的电压、电流量计算故障回路阻抗，根据线路长度与阻抗成正比的特性进行单端故障测距，简单可靠，但测距精度受到过渡电阻影响严重，尤其过渡电阻很大时，单端故障测距结果会严重偏离真实故障距离，甚至超出输电线路全长，使得单端故障测距结果失去参考价值，无法为电力系统故障巡线人员提供准确有效的故障位置信息，不利于故障位置迅速查找和故障快速排除。Single-ended fault location methods are mainly divided into traveling wave method and impedance method. The traveling wave method utilizes the transmission properties of fault transient traveling waves to perform single-ended fault location. It has high precision and is not affected by the operation mode and excessive resistance. However, it requires a high sampling rate, requires a special wave recording device, and has high application costs. . The impedance method uses the voltage and current after the fault to calculate the fault loop impedance, and performs single-ended fault distance measurement according to the characteristic that the line length is proportional to the impedance, which is simple and reliable, but the distance measurement accuracy is seriously affected by the transition resistance, especially when the transition resistance is large , the single-ended fault location results will seriously deviate from the real fault distance, and even exceed the total length of the transmission line, making the single-ended fault location results lose their reference value, and cannot provide accurate and effective fault location information for power system fault line inspectors, which is not conducive to The location of the fault can be found quickly and the fault can be quickly eliminated.

发明内容 Contents of the invention

本发明的目的在于克服已有技术存在的不足，提供一种克服了过渡电阻和负荷电流对故障距离测量精度的影响，测距原理简单，程序实现容易，运算量少，测距速度快，实时性强的利用单端电气量实现线路单相接地故障测距方法。The purpose of the present invention is to overcome the deficiencies in the prior art, to provide a method that overcomes the influence of transition resistance and load current on the fault distance measurement accuracy, has a simple principle of distance measurement, easy program implementation, less computation, fast distance measurement speed, real-time It is a powerful method of using single-ended electrical quantity to realize single-phase ground fault location method of line.

利用单端电气量实现线路单相接地故障测距方法，其特征在于，包括如下步骤：The method for realizing single-phase grounding fault distance measurement of lines by using single-ended electrical quantities is characterized in that the method comprises the following steps:

（1）保护装置测量输电线路保护安装处的故障相电压

、故障相负序电流

、故障相电流

和零序电流

；其中，φ=A、B、C相；(1) The protection device measures the fault phase voltage at the protection installation of the transmission line

, fault phase negative sequence current

, fault phase current

and zero sequence current

; Among them, φ=A, B, C phase;

（2）保护装置计算故障相电压

与故障相负序电流

的比值的虚部；(2) The protection device calculates the fault phase voltage

Negative sequence current with fault phase

The imaginary part of the ratio of ;

（3）保护装置计算单位长度输电线路电压降

与故障相负序电流

的比值的虚部(3) The protection device calculates the voltage drop of the transmission line per unit length

Negative sequence current with fault phase

The imaginary part of the ratio of

；其中，z₁、z₀分别为单位长度输电线路正序阻抗、零序阻抗；

; Among them, z ₁ and z ₀ are the positive-sequence impedance and zero-sequence impedance of the transmission line per unit length, respectively;

（4）保护装置计算输电线路保护安装处到单相接地故障点的故障距离

。(4) The protection device calculates the fault distance from the transmission line protection installation to the single-phase ground fault point

.

本发明与现有技术相比较，具有以下积极成果：Compared with the prior art, the present invention has the following positive results:

本发明方法测量输电线路保护安装处的故障相电压、故障相负序电流、故障相电流和零序电流，计算故障相电压与故障相负序电流的比值的虚部，计算单位长度输电线路电压降与故障相负序电流的比值的虚部，利用故障相电压与故障相负序电流的比值的虚部除以单位长度输电线路电压降与故障相负序电流的比值的虚部，得到输电线路保护安装处到单相接地故障点的故障距离。本发明方法利用单端电气量实现了输电线路单相接地故障距离的精确测量，克服了过渡电阻和负荷电流对故障距离测量精度的影响，测距原理简单，程序实现容易，运算量少，测距速度快，实时性强。The method of the invention measures the fault phase voltage, fault phase negative sequence current, fault phase current and zero sequence current at the protection installation place of the transmission line, calculates the imaginary part of the ratio of the fault phase voltage to the fault phase negative sequence current, and calculates the unit length transmission line voltage The imaginary part of the ratio of the fault phase voltage drop to the fault phase negative sequence current is divided by the imaginary part of the ratio of the fault phase voltage drop to the fault phase negative sequence current by the ratio of the unit length transmission line voltage drop to the fault phase negative sequence current to obtain the transmission The fault distance from the line protection installation to the single-phase ground fault point. The method of the invention realizes the precise measurement of the single-phase grounding fault distance of the transmission line by using the single-ended electrical quantity, overcomes the influence of the transition resistance and the load current on the measurement accuracy of the fault distance, has simple principle of distance measurement, easy program realization, less calculation amount, and easy measurement The distance is fast and the real-time performance is strong.

附图说明 Description of drawings

图1为应用本发明的线路输电系统示意图。Fig. 1 is a schematic diagram of a line transmission system applying the present invention.

具体实施方式 Detailed ways

下面根据说明书附图对本发明的技术方案做进一步详细表述。The technical solution of the present invention will be further described in detail according to the accompanying drawings.

图1为应用本发明的线路输电系统示意图。图1中PT为电压互感器、CT为电流互感器。保护装置对输电线路保护安装处的电压互感器PT的电压波形和电流互感器CT的电流波形进行采样得到电压、电流瞬时值。保护装置对其采样得到的电压、电流瞬时值利用傅里叶算法计算输电线路保护安装处的故障相电压

、故障相负序电流

、故障相电流

和零序电流

，作为输入量；其中，φ=A相、B相、C相。Fig. 1 is a schematic diagram of a line transmission system applying the present invention. In Fig. 1, PT is a voltage transformer, and CT is a current transformer. The protection device samples the voltage waveform of the voltage transformer PT and the current waveform of the current transformer CT at the place where the transmission line protection is installed to obtain instantaneous values of voltage and current. The protection device uses the Fourier algorithm to calculate the fault phase voltage at the protection installation of the transmission line using the instantaneous value of the voltage and current sampled

, fault phase negative sequence current

, fault phase current

and zero sequence current

, as the input quantity; among them, φ=A phase, B phase, C phase.

保护装置计算故障相电压

与故障相负序电流

的比值的虚部

。The protection device calculates the fault phase voltage

Negative sequence current with fault phase

The imaginary part of the ratio of

.

保护装置计算单位长度输电线路电压降与故障相负序电流

的比值的虚部Protection device calculation unit length transmission line voltage drop Negative sequence current with fault phase

The imaginary part of the ratio of

；其中，z₁、z₀分别为单位长度输电线路正序阻抗、零序阻抗。 ; Among them, z ₁ and z ₀ are the positive sequence impedance and zero sequence impedance of the transmission line per unit length, respectively.

由于满足

，因此本发明方法计算输电线路保护安装处到单相接地故障点的故障距离为。due to satisfaction

, so the inventive method calculates the fault distance from the transmission line protection installation place to the single-phase ground fault point as .

本发明方法利用单端电气量实现了输电线路单相接地故障距离的精确测量，克服了过渡电阻和负荷电流对故障距离测量精度的影响，测距原理简单，程序实现容易，运算量少，测距速度快，实时性强。The method of the invention realizes the precise measurement of the single-phase grounding fault distance of the transmission line by using the single-ended electrical quantity, overcomes the influence of the transition resistance and the load current on the measurement accuracy of the fault distance, has simple principle of distance measurement, easy program realization, less calculation amount, and easy measurement. The distance is fast and the real-time performance is strong.

以上所述仅为本发明的较佳具体实施例，但本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，可轻易想到的变化或替换，都应涵盖在本发明的保护范围之内。The above descriptions are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto, any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention , should be covered within the protection scope of the present invention.

1. utilize single-end electrical quantity to realize the line single phase grounding failure distance-finding method, it is characterized in that, comprise the steps:

Wherein, z ₁, z ₀Be respectively unit length transmission line of electricity positive sequence impedance, zero sequence impedance;