CN105242174A

CN105242174A - Impedance location function amplitude characteristic-based line single-phase grounding fault location method

Info

Publication number: CN105242174A
Application number: CN201510581628.XA
Authority: CN
Inventors: 曾惠敏
Original assignee: State Grid Corp of China SGCC; State Grid Fujian Electric Power Co Ltd; Maintenance Branch of State Grid Fujian Electric Power Co Ltd
Current assignee: State Grid Corp of China SGCC; State Grid Fujian Electric Power Co Ltd; Maintenance Branch of State Grid Fujian Electric Power Co Ltd
Priority date: 2015-09-14
Filing date: 2015-09-14
Publication date: 2016-01-13
Anticipated expiration: 2035-09-14
Also published as: CN105242174B

Abstract

The invention discloses a distance measuring method for a single-phase grounding fault of a line based on the amplitude characteristic of an impedance positioning function. The method of the present invention firstly measures the fault phase voltage, fault phase current, fault phase negative sequence current and zero sequence current at the protection installation place of the transmission line, calculates the boundary impedance, adopts a one-dimensional search method to sequentially calculate the comprehensive impedance at each point on the transmission line, and then Calculate the impedance location function value at each point on the transmission line in turn, and then select the distance between the point where the impedance location function value reaches the minimum on the transmission line and the transmission line protection installation as the fault distance. The method of the present invention utilizes the characteristic that the impedance positioning function value at the single-phase ground fault point of the transmission line reaches the minimum to realize the single-end accurate distance measurement of the single-phase ground fault point of the transmission line, and eliminates the transition resistance, load current and power system operation mode in principle. impact, with high ranging accuracy.

Description

Single-phase-to-earth fault location method for line based on amplitude characteristic of impedance location function

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基于阻抗定位函数幅值特性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 measuring method based on the amplitude characteristic of impedance positioning function.

背景技术Background technique

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。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，但故障测距精度受到过渡电阻和负荷电流等因素影响严重，尤其过渡电阻较大时，阻抗法测距结果会严重偏离真实故障距离，甚至出现故障测距失败或故障测距结果超出线路全长，无法提供准确的故障位置信息，导致故障巡线困难，不利于输电线路故障快速排除和线路供电快速恢复。The single-ended fault location method 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. 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 location based on the characteristic that the line length is proportional to the impedance. It is simple and reliable, but the fault location accuracy is seriously affected by factors such as transition resistance and load current. Especially when the transition resistance is large, the result of the impedance method distance measurement will seriously deviate from the real fault distance, and even the fault distance measurement fails or the fault distance measurement result exceeds the entire length of the line, which cannot provide accurate fault location information, making it difficult to inspect the fault line. It is conducive to the rapid elimination of transmission line faults and the rapid restoration of line power supply.

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，提供一种基于阻抗定位函数幅值特性线路单相接地故障测距方法。该方法采用集总参数建模，算法原理简单，程序实现容易，计算量小，故障测距速度快。该方法利用输电线路单相接地故障点处的阻抗定位函数值达到最小这一特性实现输电线路单相接地故障单端精确测距，原理上消除了过渡电阻和负荷电流及电力系统运行方式的影响，具有很高的测距精度，适用于实现500kV、220kV及110kV输电线路单相接地故障的单端测距功能。The purpose of the present invention is to overcome the deficiencies in the prior art, and provide a single-phase ground fault distance measurement method based on the amplitude characteristic of the impedance location function. The method adopts lumped parameter modeling, the algorithm principle is simple, the program is easy to implement, the calculation amount is small, and the fault distance measurement speed is fast. This method utilizes the characteristic that the impedance location function value at the single-phase-to-ground fault point of the transmission line reaches the minimum to realize single-end accurate distance measurement of the single-phase-to-ground fault of the transmission line, and eliminates the influence of transition resistance, load current and power system operation mode in principle , with high ranging accuracy, suitable for realizing single-ended ranging function of single-phase ground fault of 500kV, 220kV and 110kV transmission lines.

为完成上述目的，本发明采用如下技术方案：For accomplishing above-mentioned object, the present invention adopts following technical scheme:

基于阻抗定位函数幅值特性线路单相接地故障测距方法，其特征在于，包括如下步骤：The single-phase grounding fault distance measuring method based on the amplitude characteristic of the impedance positioning function is characterized in that it 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)保护装置计算边界阻抗 $Δ Z = \frac{{\overset{\cdot}{I}}_{φ 2}}{{\overset{\cdot}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{\cdot}{I}}_{0}} \frac{Im (\frac{{\overset{\cdot}{U}}_{φ}}{z_{1} ({\overset{\cdot}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{\cdot}{I}}_{0})})}{Im (\frac{{\overset{\cdot}{I}}_{φ 2}}{z_{1} ({\overset{\cdot}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{\cdot}{I}}_{0})})};$ (2) The protection device calculates the boundary impedance $Δ Z = \frac{{\overset{\cdot}{I}}_{φ 2}}{{\overset{&Center Dot;}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{&Center Dot;}{I}}_{0}} \frac{Im (\frac{{\overset{&Center Dot;}{u}}_{φ}}{z_{1} ({\overset{\cdot}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{&Center Dot;}{I}}_{0})})}{Im (\frac{{\overset{&Center Dot;}{I}}_{φ 2}}{z_{1} ({\overset{\cdot}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{\cdot}{I}}_{0})})};$

其中，z₁、z₀分别为单位长度输电线路正序阻抗、零序阻抗；为的虚部；为的虚部；φ＝A、B、C相；Among them, z ₁ and z ₀ are the positive-sequence impedance and zero-sequence impedance of the transmission line per unit length, respectively; for the imaginary part of for The imaginary part of ; φ = A, B, C phase;

(3)保护装置选取故障距离初始值为l_x，计算距离输电线路保护安装处的l_x点的综合阻抗ΔZ+z₁l_x；(3) The protection device selects the initial value of the fault distance as lx, and calculates the comprehensive impedance ΔZ+ _z ₁ lx at the lx point where the transmission line protection _is installed _;

(4)保护装置计算距离输电线路保护安装处的l_x点的阻抗定位函数值(4) The protection device calculates the impedance positioning function value of the point l _x point away from the transmission line protection installation

$| | \frac{{\overset{\cdot \cdot}{U u}}_{φ φ}}{{\overset{\cdot \cdot}{I I}}_{φ φ} + + \frac{{z z}_{00} - - {z z}_{11}}{{z z}_{11}} {\overset{\cdot \cdot}{I I}}_{00}} - - ((Δ Δ Z Z + + {z z}_{11} {l l}_{x x})) | |;;$

(5)故障距离l_x以固定步长Δl递增，返回步骤(3)，依次计算输电线路上每一l_x点的阻抗定位函数值直至输电线路全长；(5) The fault distance l _x increases with a fixed step size Δl, return to step (3), and calculate the impedance location function value of each l _x point on the transmission line in turn up to the full length of the transmission line;

(6)保护装置选取输电线路上阻抗定位函数值最小对应的点距输电线路保护安装处的距离为故障距离；其中，固定步长Δl取0.001l，l为输电线路长度。(6) The protection device selects the impedance positioning function value on the transmission line The distance between the minimum corresponding point and the installation place of transmission line protection is the fault distance; among them, the fixed step size Δl is taken as 0.001l, and l is the length of the transmission line.

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:

本发明方法首先测量输电线路保护安装处故障相电压、故障相电流、故障相负序电流和零序电流，计算边界阻抗，采用一维搜索方法依次计算输电线路上每一点处的综合阻抗，进而依次计算输电线路上每一点处的阻抗定位函数值，然后选取输电线路上阻抗定位函数值达到最小的点距输电线路保护安装处的距离为故障距离。本发明方法采用集总参数建模，算法原理简单，程序实现容易，计算量小，故障测距速度快。本发明方法利用输电线路单相接地故障点处的阻抗定位函数值达到最小这一特性实现输电线路单相接地故障单端精确测距，原理上消除了过渡电阻和负荷电流及电力系统运行方式的影响，具有很高的测距精度，适用于实现500kV、220kV及110kV输电线路单相接地故障的单端测距功能。The method of the present invention first measures the fault phase voltage, fault phase current, fault phase negative sequence current and zero sequence current at the protection installation of the transmission line, calculates the boundary impedance, and uses a one-dimensional search method to calculate the comprehensive impedance at each point on the transmission line in sequence, and then Calculate the impedance location function value at each point on the transmission line in turn, and then select the distance between the point where the impedance location function value reaches the minimum on the transmission line and the transmission line protection installation as the fault distance. The method of the invention adopts lumped parameter modeling, the algorithm principle is simple, the program is easy to realize, the calculation amount is small, and the fault distance measurement speed is fast. The method of the present invention utilizes the characteristic that the impedance positioning function value at the single-phase ground fault point of the transmission line reaches the minimum to realize the single-end precise distance measurement of the single-phase ground fault point of the transmission line, and eliminates the transition resistance, load current and power system operation mode in principle. It has high ranging accuracy and is suitable for single-end ranging function of single-phase ground fault of 500kV, 220kV and 110kV transmission lines.

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 description

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，并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 transmission line protection installation to obtain the instantaneous voltage and current values, and calculates the fault phase voltage at the transmission line protection installation by using the Fourier algorithm Fault phase negative sequence current fault phase current and zero sequence current As an input quantity; where, φ=A phase, B phase, C phase;

保护装置计算边界阻抗 $Δ Z = \frac{{\overset{\cdot}{I}}_{φ 2}}{{\overset{\cdot}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{\cdot}{I}}_{0}} \frac{Im (\frac{{\overset{\cdot}{U}}_{φ}}{z_{1} ({\overset{\cdot}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{\cdot}{I}}_{0})})}{Im (\frac{{\overset{\cdot}{I}}_{φ 2}}{z_{1} ({\overset{\cdot}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{\cdot}{I}}_{0})})};$ The protection device calculates the boundary impedance $Δ Z = \frac{{\overset{\cdot}{I}}_{φ 2}}{{\overset{&Center Dot;}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{&Center Dot;}{I}}_{0}} \frac{Im (\frac{{\overset{&Center Dot;}{u}}_{φ}}{z_{1} ({\overset{&Center Dot;}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{&Center Dot;}{I}}_{0})})}{Im (\frac{{\overset{\cdot}{I}}_{φ 2}}{z_{1} ({\overset{&Center Dot;}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{&Center Dot;}{I}}_{0})})};$

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

保护装置利用故障相电压除以零序补偿电流得到测量阻抗The protection device utilizes the fault phase voltage Divided by the zero-sequence compensation current get measured impedance

$\frac{{\overset{\cdot &Center Dot;}{U u}}_{φ φ}}{{\overset{\cdot \cdot}{I I}}_{φ φ} + + \frac{{z z}_{00} - - {z z}_{11}}{{z z}_{11}} {\overset{\cdot &Center Dot;}{I I}}_{00}} . .$

保护装置选取故障距离初始值为l_x，计算距离输电线路保护安装处的l_x点的综合阻抗ΔZ+z₁l_x。The protection device selects the initial value of the fault distance as l _x , and calculates the comprehensive impedance ΔZ+z ₁ l _x at the point l _x from where the transmission line protection is installed.

保护装置计算距离输电线路保护安装处的l_x点的阻抗定位函数值The protection device calculates the impedance positioning function value of the l _x point from where the transmission line protection is installed

$| | \frac{{\overset{\cdot \cdot}{U u}}_{φ φ}}{{\overset{\cdot \cdot}{I I}}_{φ φ} + + \frac{{z z}_{00} - - {z z}_{11}}{{z z}_{11}} {\overset{\cdot &Center Dot;}{I I}}_{00}} - - ((Δ Δ Z Z + + {z z}_{11} {l l}_{x x})) | | . .$

故障距离l_x以固定步长Δl递增，依次计算输电线路上每一l_x点的阻抗定位函数值直至输电线路全长；其中，固定步长Δl取0.001l，l为输电线路长度。The fault distance l _x increases with a fixed step size Δl, and the impedance location function value of each l _x point on the transmission line is calculated sequentially Up to the full length of the transmission line; where, the fixed step size Δl is 0.001l, and l is the length of the transmission line.

上述过程中，故障距离l_x从0开始并以固定步长Δl递增，直至输电线路全长结束完成输电线路上每一l_x点处的阻抗定位函数值计算。In the above process, the fault distance _lx starts from 0 and increases with a fixed step size Δl until the end of the entire length of the transmission line to complete the calculation of the impedance positioning function value at each _lx point on the transmission line.

最后，保护装置选取输电线路上阻抗定位函数值最小对应的点距输电线路保护安装处的距离为故障距离。Finally, the protection device selects the impedance positioning function value on the transmission line The distance from the minimum corresponding point to the installation of transmission line protection is the fault distance.

本发明方法采用集总参数建模，算法原理简单，程序实现容易，计算量小，故障测距速度快。本发明方法利用输电线路单相接地故障点处的阻抗定位函数值达到最小这一特性实现输电线路单相接地故障单端测距，原理上消除了过渡电阻和负荷电流及电力系统运行方式的影响，具有很高的测距精度。The method of the invention adopts lumped parameter modeling, the algorithm principle is simple, the program is easy to realize, the calculation amount is small, and the fault distance measurement speed is fast. The method of the invention utilizes the characteristic that the impedance positioning function value at the single-phase ground fault point of the transmission line reaches the minimum to realize the single-end distance measurement of the single-phase ground fault point of the transmission line, and eliminates the influence of the transition resistance, load current and power system operation mode in principle , with high ranging accuracy.

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.

Claims

1., based on impedance mapping function amplitude characteristic line single phase grounding failure distance-finding method, it is characterized in that, comprise the steps:

(1) faulted phase voltage of protector measuring line protection installation place fault phase negative-sequence current faulted phase current and zero-sequence current wherein, φ=A, B, C phase;

(2) protective device computation bound impedance

Δ Z = \frac{{\overset{\cdot}{I}}_{φ 2}}{{\overset{\cdot}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{\cdot}{I}}_{0}} \frac{Im (\frac{{\overset{\cdot}{U}}_{φ}}{z_{1} ({\overset{\cdot}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{\cdot}{I}}_{0})})}{I m (\frac{{\overset{\cdot}{I}}_{φ 2}}{z_{1} ({\overset{\cdot}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{\cdot}{I}}_{0})})};

Wherein, z ₁, z ₀be respectively the impedance of unit length electric transmission line positive sequence, zero sequence impedance; for imaginary part; for imaginary part; φ=A, B, C phase;

(3) fault distance initial value chosen by protective device is l _x, calculate the l of distance line protection installation place _xthe comprehensive impedance Δ Z+z of point ₁l _x;

(4) protective device calculates the l of distance line protection installation place _xthe impedance mapping function value of point

| \frac{{\overset{\cdot}{U}}_{φ}}{{\overset{\cdot}{I}}_{φ} + \frac{z_{0} - z_{1}}{z_{1}} {\overset{\cdot}{I}}_{0}} - (Δ Z + z_{1} l_{x}) |;

(5) fault distance l _xincrease progressively with fixed step size Δ l, return step (3), successively each l on computing electric power line _xthe impedance mapping function value of point until transmission line of electricity total length;

(6) impedance mapping function value on transmission line of electricity chosen by protective device the distance of the some distance line protection installation place of minimum correspondence is fault distance; Wherein, fixed step size Δ l gets 0.001l, and l is transmission line length.