CN104062552A

CN104062552A - Non-same-phase overline ground fault single-ended distance measurement method for double-circuit lines

Info

Publication number: CN104062552A
Application number: CN201410318837.0A
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; Putian Power Supply Co of State Grid Fujian Electric Power Co Ltd
Priority date: 2014-07-04
Filing date: 2014-07-04
Publication date: 2014-09-24

Abstract

The invention discloses a single-end ranging method for non-identical phase cross-line grounding faults of double-circuit lines: measuring the fault phase voltage, fault phase current and zero-sequence current at the protection installation place of the I-circuit line of the double-circuit line on the same pole, and calculating the same pole The phase angle of the zero-sequence current of the phase angle of the zero-sequence current of the non-identical phase cross-line ground fault point is injected into the fault phase voltage at the installation place of the I-circuit line protection of parallel double-circuit lines, and then the fault phase voltage before and after the non-identical phase cross-line ground fault point is used to lag behind the same pole and parallel The phase angle of the fault phase voltage at the installation place of the I-circuit line protection of the double-circuit line on the double-circuit line will be smaller than the phase angle of the fault phase voltage at the installation place of the I-circuit line protection installation of the double-circuit line on the same pole. The phase angle of the current changes suddenly to be greater than the phase angle of the phase angle of the zero-sequence current of the phase angle of the zero-sequence current at the fault point of the grounding fault point of the non-identical phase at the I-circuit line protection installation of the double-circuit line parallel to the same pole. This vector phase change characteristic realizes the double-circuit line Accurate location of non-identical phase-to-ground faults.

Description

Single-ended ranging method for non-identical phase-cross-line grounding faults of double-circuit lines

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矢量相位比较的双回线路非同名相跨线接地故障单端测距方法。The invention relates to the technical field of electric power system relay protection, in particular to a single-end distance measurement method for non-identical phase cross-line grounding faults of double-circuit lines based on vector phase comparison.

背景技术Background technique

从测距所用电气量来划分，故障测距的方法可分为两大类：双端测距和单端测距。双端故障测距法是利用输电线路两端电气量确定输电线路故障位置的方法，它需要通过通道获取对端电气量，因此对通道的依赖性强，实际使用中还易受双端采样值同步性的影响。单端测距法是仅利用输电线路一端的电压电流数据确定输电线路故障位置的一种方法，由于它仅需要一端数据，无须通讯和数据同步设备，运行费用低且算法稳定，因此在中低压线路中获得了广泛地应用。目前，单端测距方法主要分为两类，一类为行波法，另一类为阻抗法。行波法利用故障暂态行波的传送性质进行测距，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，目前未获得实质性的应用。阻抗法利用故障后的电压、电流量计算故障回路的阻抗，根据线路长度与阻抗成正比的特性进行测距，测距原理简单可靠，但应用于同杆并架双回线路单相接地故障单端故障测距时，测距精度受到故障点过渡电阻和线间零序互感影响严重。同杆并架双回线路线间存在零序互感，零序互感会对零序补偿系数产生影响，进而导致阻抗法测距结果误差偏大。若同杆并架双回线路发生单相高阻接地故障，受线间零序互感和高过渡电阻综合影响，阻抗法测距结果常常超出线路全长或无测距结果，无法提供准确的故障位置信息，导致线路故障巡线困难，不利于故障快速排出和线路供电快速恢复。Divided from the electrical quantity used for distance measurement, fault location methods can be divided into two categories: double-ended ranging and single-ended ranging. The double-terminal fault location method is a method to determine the fault location of the transmission line by using the electrical quantity at both ends of the transmission line. It needs to obtain the electrical quantity of the opposite end through the channel, so it is highly dependent on the channel, and it is also vulnerable to the double-terminal sampling value in actual use. Synchronization effects. The single-ended ranging method is a method that only uses the voltage and current data at one end of the transmission line to determine the fault location of the transmission line. Because it only needs data at one end, does not require communication and data synchronization equipment, and has low operating costs and stable algorithms, it is suitable for medium and low voltage applications. It has been widely used in the line. At present, the single-ended ranging methods are mainly divided into two categories, one is the traveling wave method, and the other is the impedance method. The traveling wave method utilizes the transmission properties of fault transient traveling waves for distance measurement. It has high precision and is not affected by the operation mode and excessive resistance. application. The impedance method uses the voltage and current after the fault to calculate the impedance of the fault loop, and performs distance measurement according to the characteristic that the length of the line is proportional to the impedance. When fault location is performed at the end of the fault, the distance measurement accuracy is seriously affected by the transition resistance of the fault point and the zero-sequence mutual inductance between the lines. There is zero-sequence mutual inductance between double-circuit lines on the same pole, and the zero-sequence mutual inductance will affect the zero-sequence compensation coefficient, which will lead to large errors in the ranging results of the impedance method. If a single-phase high-resistance grounding fault occurs on a parallel double-circuit line on the same pole, due to the comprehensive influence of the zero-sequence mutual inductance and high transition resistance between the lines, the ranging result of the impedance method often exceeds the full length of the line or there is no ranging result, which cannot provide accurate fault information Location information makes it difficult to inspect line faults, which is not conducive to rapid troubleshooting and 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，提供一种基于矢量相位比较的双回线路非同名相跨线接地故障单端测距方法，该方法计算同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的相角，利用非同名相跨线接地故障点前后的故障相电压滞后同杆并架双回线路I回线路保护安装处故障相电压的相角会发生唯一一次的，由小于同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的相角突变为大于同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的相角这一矢量相位变化特性，实现双回线路非同名相跨线接地故障的精确测距，消除了线间零序互感、过渡电阻和负荷电流对故障测距精度的影响，具有很强的抗过渡电阻和负荷电流影响的能力，保护正方向出口发生双回线路非同名相跨线接地故障时无故障测距死区。The purpose of the present invention is to overcome the deficiencies in the prior art, to provide a single-ended distance measurement method for double-circuit line non-identical phase cross-line grounding faults based on vector phase comparison, the method calculates the I-circuit line of the double-circuit line on the same pole The phase angle of zero-sequence current is injected into the phase angle of the zero-sequence current at the ground fault point of the non-identical phase across the line, and the fault phase voltage before and after the ground fault point of the phase of the non-identical phase is lagged behind the same pole parallel double-circuit line. The phase angle of the fault phase voltage at the fault point will occur only once, and the phase angle of the zero-sequence current at the fault point where the fault phase voltage at the I-circuit line protection installation of the parallel double-circuit line on the same pole is leading to injection into a non-identical phase cross-line grounding fault point suddenly changes to a phase angle greater than The phase angle of the phase angle of the zero-sequence current at the fault point of the non-synonymous phase crossing the ground fault point of the phase angle of the phase change characteristic of the phase angle of the zero-sequence current of the non-synonymous phase at the fault phase voltage at the protection installation of the double-circuit line paralleled on the same pole realizes the non-synonymous phase crossing the line grounding fault of the double-circuit line Accurate distance measurement eliminates the influence of zero-sequence mutual inductance between lines, transition resistance and load current on the accuracy of fault distance measurement, and has a strong ability to resist the influence of transition resistance and load current, and protects the double-circuit line with the same name at the exit of the positive direction. There is no dead zone for fault distance measurement when the phase-crossing line is grounded.

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:

双回线路非同名相跨线接地故障单端测距方法，其特征在于，包括如下依序步骤：The single-ended distance measuring method for non-identical phase-cross-line grounding faults of double-circuit lines is characterized in that it includes the following sequential steps:

(1)保护装置测量同杆并架双回线路I回线路保护安装处的故障相电压故障相电流和零序电流其中，φ＝I回线路A相或I回线路B相或I回线路C相；(1) The protection device measures the fault phase voltage at the protection installation of the I-circuit line of the double-circuit line on the same pole fault phase current and zero sequence current Wherein, φ=I loop line A phase or I loop line B phase or I loop line C phase;

(2)保护装置计算同杆并架双回线路I回线路的零序补偿电流 (2) The protection device calculates the zero-sequence compensation current of the I-circuit line of the parallel double-circuit line on the same pole

$Δ Δ \overset{\cdot &Center Dot;}{I I} = = {\overset{\cdot \cdot}{I I}}_{Iφ Iφ} + + \frac{{Z Z}_{I I 00} - - {Z Z}_{I I 11}}{{Z Z}_{I I 11}} {\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + \frac{{Z Z}_{m m}}{{33 Z Z}_{I I 11}} {\overset{\cdot &Center Dot;}{I I}}_{I I 00} ((- - cos cos (({r r}_{11} + + {r r}_{22} - - β β)) - - j j sin sin (({r r}_{11} + + {r r}_{22} - - β β))))$

其中， $r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}});$ $r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}});$ $a_{1} = Re (\frac{{\overset{\cdot}{U}}_{Iφ}}{Z_{I 1}});$ $b_{1} = Im (\frac{{\overset{\cdot}{U}}_{Iφ}}{Z_{I 1}});$ $a_{2} = Re ({\overset{\cdot}{I}}_{Iφ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0});$ $b_{2} = Im ({\overset{\cdot}{I}}_{Iφ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0});$ $a_{3} = b_{3} = | \frac{Z_{m}}{{3 Z}_{I 1}} {\overset{\cdot}{I}}_{I 0} |;$ $β = Arg (\frac{Z_{m}}{{3 Z}_{I 1}} {\overset{\cdot}{I}}_{I 0});$ Z_m为同杆并架双回线路I回线路与同杆并架双回线路II回线路之间的零序互感；Z_I0为同杆并架双回线路I回线路的零序阻抗；Z_I1为同杆并架双回线路I回线路的正序阻抗；φ＝I回线路A相或I回线路B相或I回线路C相；为的实部；为的虚部；为的实部；为的虚部；j为复数算子；in, $r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}});$ $r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}});$ $a_{1} = Re (\frac{{\overset{\cdot}{u}}_{Iφ}}{Z_{I 1}});$ $b_{1} = Im (\frac{{\overset{&Center Dot;}{u}}_{Iφ}}{Z_{I 1}});$ $a_{2} = Re ({\overset{&Center Dot;}{I}}_{Iφ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0});$ $b_{2} = Im ({\overset{&Center Dot;}{I}}_{Iφ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0});$ $a_{3} = b_{3} = | \frac{Z_{m}}{{3 Z}_{I 1}} {\overset{\cdot}{I}}_{I 0} |;$ $β = Arg (\frac{Z_{m}}{{3 Z}_{I 1}} {\overset{&Center Dot;}{I}}_{I 0});$ Z _m is the zero-sequence mutual inductance between the I-circuit line of the parallel double-circuit line on the same pole and the II-circuit line of the parallel double-circuit line on the same pole; Z _I0 is the zero-sequence impedance of the I-circuit line of the parallel double-circuit line on the same pole; Z _I1 is the positive sequence impedance of the I-circuit line of the double-circuit line on the same pole; φ=I-circuit line A phase or I-circuit line B-phase or I-circuit line C-phase; for the real part of for the imaginary part of for the real part of for the imaginary part of ; j is a complex operator;

(3)保护装置计算同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的角度ρ：(3) The protection device calculates the fault phase voltage at the installation place of the I-circuit line protection of the parallel double-circuit line on the same pole Take the lead in injecting the zero-sequence current of the non-identical phase cross-line grounding fault point The angle ρ of:

$ρ ρ = = Arg Arg ((\frac{{\overset{\cdot \cdot}{U u}}_{Iφ Iφ}}{{\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + {\overset{\cdot &Center Dot;}{I I}}_{I I 00} ((- - cos cos (({r r}_{11} + + {r r}_{22} - - β β)) - - j j sin sin (({r r}_{11} + + {r r}_{22} - - β β))))}))$

(4)保护装置选取故障距离初始值为l_x，计算距离同杆并架双回线路I回线路保护安装处l_x点的故障相电压其中，l为同杆并架双回线路I回线路长度；(4) The protection device selects the initial value of the fault distance as l _x , and calculates the fault phase voltage at the point l _x where the protection installation point of the I-circuit line is installed on the double-circuit line on the same pole Among them, l is the length of the I-circuit line of the parallel double-circuit line on the same pole;

(5)保护装置计算领先距离同杆并架双回线路I回线路保护安装处l_x点的故障相电压的相角 $λ (l_{x}) = Arg (\frac{{\overset{\cdot}{U}}_{Iφ}}{\overset{\cdot}{U} (l_{x})});$ (5) Protection device calculation Faulty phase voltage at point l _x where protection is installed for double-circuit line I on the same pole parallel to the leading distance phase angle of $λ (l_{x}) = Arg (\frac{{\overset{&Center Dot;}{u}}_{Iφ}}{\overset{&Center Dot;}{u} (l_{x})});$

(6)故障距离l_x以固定步长Δl递增，返回步骤(4)，依次计算同杆并架双回线路I回线路上每一l_x点的直至同杆并架双回线路I回线路全长；(6) The fault distance l _x increases with a fixed step size Δl, returns to step (4), and calculates the distance of each l _x point on the double-circuit line I of the double-circuit line on the same pole in turn Up to the full length of the I-circuit line of the parallel double-circuit line on the same pole;

(7)保护装置选取同杆并架双回线路I回线路上某一l_x点处满足且其相邻下一个l_x+Δl点处满足则这两个点的中间位置即为同杆并架双回线路的非同名相跨线接地故障点；其中，Δl为固定步长。(7) The protection device selects a certain point l _x on the double-circuit line on the same pole parallel to the I-circuit line to meet the And its adjacent next l _x + Δl point satisfies Then the middle position of these two points is the grounding fault point of the non-synonymous phase-crossing line of the parallel double-circuit line on the same pole; among them, Δl is a fixed step size.

本发明的特点及技术成果：Features and technical achievements of the present invention:

本发明方法只用到单端单回线路电气量，不需要引入另一回线路电气量，保护二次回路相互独立不互串，增强故障测距结果准确性，且故障测距精度不受电力系统运行方式的影响，在电力系统运行方式发生较大改变时仍具有很高的测距精度。本发明方法计及线间零序互感的影响，消除了线间零序互感对故障测距精度的影响。The method of the present invention only uses the electrical quantity of the single-ended single-circuit circuit, and does not need to introduce the electrical quantity of another circuit, so as to protect the secondary circuits from being independent from each other and not intersecting each other, thereby enhancing the accuracy of fault location results, and the accuracy of fault location measurement is not affected by electric power. Influenced by the operation mode of the system, it still has a high ranging accuracy when the operation mode of the power system changes greatly. The method of the invention takes into account the influence of zero-sequence mutual inductance between lines, and eliminates the influence of zero-sequence mutual inductance between lines on the accuracy of fault distance measurement.

本发明方法计算同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的相角，利用非同名相跨线接地故障点前后的故障相电压滞后同杆并架双回线路I回线路保护安装处故障相电压的相角会发生唯一一次的，由小于同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的相角突变为大于同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的相角这一矢量相位变化特性，实现双回线路非同名相跨线接地故障的精确测距，消除线间零序互感、过渡电阻和负荷电流对故障测距精度的影响，具有很强的抗过渡电阻和负荷电流影响的能力，保护正方向出口发生双回线路非同名相跨线接地故障时无故障测距死区。The method of the present invention calculates the phase angle of the zero-sequence current of the fault phase voltage at the I-circuit line protection installation place of the double-circuit line paralleled on the same pole and injects the phase angle of the zero-sequence current at the ground fault point of the non-identical phase across the line, and utilizes the fault phase before and after the ground fault point of the non-identical phase across the line Voltage lag The phase angle of the fault phase voltage at the installation place of the I-circuit line protection of the double-circuit line paralleled on the same pole will occur only once, and the phase angle of the fault phase voltage at the installation place of the I-circuit line protection of the double-circuit line paralleled on the same pole will be lower than that of the phase angle of the fault phase voltage at the installation place of the I-circuit line protection of the double-circuit line paralleled on the same pole. The phase angle of the zero-sequence current at the cross-line grounding fault point suddenly becomes larger than the phase angle of the phase angle of the zero-sequence current at the cross-line grounding fault point of the same-pole parallel double-circuit line I-circuit line protection installation. Variation characteristics, realize accurate distance measurement of non-identical phase cross-line grounding faults of double-circuit lines, eliminate the influence of zero-sequence mutual inductance, transition resistance and load current on fault location accuracy, and have strong resistance to transition resistance and load current influence The ability to protect the positive direction exit without fault ranging dead zone when a double-circuit line with a non-identical phase cross-line ground fault occurs.

附图说明Description of drawings

图1为应用本发明的同杆并架双回线路输电系统示意图。Fig. 1 is a schematic diagram of a double-circuit line power transmission system on the same pole parallel to the rack applying the present invention.

具体实施方式Detailed ways

图1为应用本发明的同杆并架双回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。保护装置测量同杆并架双回线路I回线路保护安装处的故障相电压故障相电流和零序电流其中，φ＝I回线路A相或I回线路B相或I回线路C相。Fig. 1 is a schematic diagram of a double-circuit line power transmission system on the same pole parallel to the rack applying the present invention. In Fig. 1, PT is a voltage transformer; CT is a current transformer. The protection device measures the fault phase voltage at the protection installation place of the I-circuit line of double-circuit lines paralleled on the same pole fault phase current and zero sequence current Wherein, φ=I circuit line A phase or I circuit line B phase or I circuit line C phase.

保护装置计算同杆并架双回线路II回线路的零序电流 The protection device calculates the zero-sequence current of the double-circuit line II on the same pole

其中， $r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}});$ $r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}});$ $a_{1} = Re (\frac{{\overset{\cdot}{U}}_{Iφ}}{Z_{I 1}});$ $b_{1} = Im (\frac{{\overset{\cdot}{U}}_{Iφ}}{Z_{I 1}});$ $a_{2} = Re ({\overset{\cdot}{I}}_{Iφ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0});$ $b_{2} = Im ({\overset{\cdot}{I}}_{Iφ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0});$ $a_{3} = b_{3} = | \frac{Z_{m}}{{3 Z}_{I 1}} {\overset{\cdot}{I}}_{I 0} |;$ $β = Arg (\frac{Z_{m}}{{3 Z}_{I 1}} {\overset{\cdot}{I}}_{I 0});$ Z_m为同杆并架双回线路I回线路与同杆并架双回线路II回线路之间的零序互感；Z_I0为同杆并架双回线路I回线路的零序阻抗；Z_I1为同杆并架双回线路I回线路的正序阻抗；φ＝I回线路A相或I回线路B相或I回线路C相；为的实部；为的虚部；为的实部；为的虚部；j为复数算子。in, $r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}});$ $r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}});$ $a_{1} = Re (\frac{{\overset{\cdot}{u}}_{Iφ}}{Z_{I 1}});$ $b_{1} = Im (\frac{{\overset{&Center Dot;}{u}}_{Iφ}}{Z_{I 1}});$ $a_{2} = Re ({\overset{\cdot}{I}}_{Iφ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0});$ $b_{2} = Im ({\overset{&Center Dot;}{I}}_{Iφ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0});$ $a_{3} = b_{3} = | \frac{Z_{m}}{{3 Z}_{I 1}} {\overset{\cdot}{I}}_{I 0} |;$ $β = Arg (\frac{Z_{m}}{{3 Z}_{I 1}} {\overset{&Center Dot;}{I}}_{I 0});$ Z _m is the zero-sequence mutual inductance between the I-circuit line of the parallel double-circuit line on the same pole and the II-circuit line of the parallel double-circuit line on the same pole; Z _I0 is the zero-sequence impedance of the I-circuit line of the parallel double-circuit line on the same pole; Z _I1 is the positive sequence impedance of the I-circuit line of the double-circuit line on the same pole; φ=I-circuit line A phase or I-circuit line B-phase or I-circuit line C-phase; for the real part of for the imaginary part of for the real part of for The imaginary part of ; j is a complex operator.

保护装置计算同杆并架双回线路I回线路的零序补偿电流 The protection device calculates the zero-sequence compensation current of the I-circuit line of the parallel double-circuit line on the same pole

$Δ Δ \overset{\cdot &Center Dot;}{I I} = = {\overset{\cdot &Center Dot;}{I I}}_{Iφ Iφ} + + \frac{{Z Z}_{I I 00} - - {Z Z}_{I I 11}}{{Z Z}_{I I 11}} {\overset{\cdot \cdot}{I I}}_{I I 00} + + \frac{{Z Z}_{m m}}{{33 Z Z}_{I I 11}} {\overset{\cdot \cdot}{I I}}_{II II 00}$

其中，Z_m为同杆并架双回线路I回线路与同杆并架双回线路II回线路之间的零序互感；Z_I0为同杆并架双回线路I回线路的零序阻抗；Z_I1为同杆并架双回线路I回线路的正序阻抗；φ＝I回线路A相或I回线路B相或I回线路C相。Among them, Z _m is the zero-sequence mutual inductance between the I-circuit line of the parallel double-circuit line on the same pole and the II-circuit line of the parallel double-circuit line on the same pole; Z _I0 is the zero-sequence impedance of the I-circuit line of the parallel double-circuit line on the same pole ; Z _I1 is the positive sequence impedance of the I-circuit line of the double-circuit line on the same pole; φ=I-circuit line A phase or I-circuit line B-phase or I-circuit line C-phase.

保护装置计算同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的角度ρ：The protection device calculates the fault phase voltage at the installation place of the I-circuit line protection of double-circuit lines paralleled on the same pole Take the lead in injecting the zero-sequence current of the non-identical phase cross-line grounding fault point The angle ρ of:

$ρ ρ = = Arg Arg ((\frac{{\overset{\cdot &Center Dot;}{U u}}_{Iφ Iφ}}{{\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + {\overset{\cdot \cdot}{I I}}_{I I 00} ((- - cos cos (({r r}_{11} + + {r r}_{22} - - β β)) - - j j sin sin (({r r}_{11} + + {r r}_{22} - - β β))))}))$

利用非同名相跨线接地故障点前后的故障相电压滞后同杆并架双回线路I回线路保护安装处故障相电压的相角会发生唯一一次的，由小于同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的相角突变为大于同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的相角这一矢量相位变化特性，实现双回线路非同名相跨线接地故障的精确测距，具体测距搜索步骤如下：The phase angle of the fault phase voltage at the installation place of the double-circuit line I-circuit line protection on the same pole will only occur once when the phase angle of the fault phase voltage is smaller than that of the double-circuit line I line on the same pole. The phase angle of the zero-sequence current at the point of the zero-sequence current suddenly becomes greater than that of the double-circuit line on the same pole, and the fault phase voltage at the protection installation of the circuit line is injected into the non-identical phase across the line. The vector phase change characteristic of the phase angle of the zero-sequence current at the ground fault point realizes the accurate distance measurement of the non-identical phase cross-line ground fault of the double-circuit line. The specific distance measurement search steps are as follows:

(1)保护装置选取故障距离初始值为l_x，计算距离同杆并架双回线路I回线路保护安装处l_x点的故障相电压其中，l为同杆并架双回线路I回线路长度；(1) The protection device selects the initial value of the fault distance as l _x , and calculates the fault phase voltage at the point l _x where the protection installation point of the I-circuit line is installed on the double-circuit line on the same pole Among them, l is the length of the I-circuit line of the parallel double-circuit line on the same pole;

(2)保护装置计算领先距离同杆并架双回线路I回线路保护安装处l_x点的故障相电压的相角 $λ (l_{x}) = Arg (\frac{{\overset{\cdot}{U}}_{Iφ}}{\overset{\cdot}{U} (l_{x})});$ (2) Protection device calculation Faulty phase voltage at point l _x where protection is installed for double-circuit line I on the same pole parallel to the leading distance phase angle of $λ (l_{x}) = Arg (\frac{{\overset{\cdot}{u}}_{Iφ}}{\overset{\cdot}{u} (l_{x})});$

(3)故障距离l_x以固定步长Δl递增，返回步骤(1)，依次计算同杆并架双回线路I回线路上每一l_x点的直至同杆并架双回线路I回线路全长；其中，Δl为固定步长；(3) The fault distance l _x increases with a fixed step size Δl, and returns to step (1), and calculates the distance of each l _x point on the double-circuit line I of the double-circuit line on the same pole in turn Up to the full length of the I-circuit line of the parallel double-circuit line on the same pole; where, Δl is a fixed step length;

(4)保护装置选取同杆并架双回线路I回线路上某一l_x点处满足且其相邻下一个l_x+Δl点处满足则这两个点的中间位置即为同杆并架双回线路的非同名相跨线接地故障点；其中， $\overset{\cdot}{U} (Δl + l_{x}) = {\overset{\cdot}{U}}_{Iφ} - \frac{Δl + l_{x}}{l} Z_{I 1} Δ \overset{\cdot}{I} .$ (4) The protection device selects a certain point l _x on the double-circuit line on the same pole and erects the double-circuit line to satisfy And its adjacent next l _x + Δl point satisfies Then the middle position of these two points is the grounding fault point of the non-synonymous phase-crossing line of the parallel double-circuit line on the same pole; among them, $\overset{\cdot}{u} (Δl + l_{x}) = {\overset{&Center Dot;}{u}}_{Iφ} - \frac{Δl + l_{x}}{l} Z_{I 1} Δ \overset{\cdot}{I} .$

本发明方法只用到单端单回线路电气量，不需要引入另一回线路电气量，保护二次回路相互独立不互串，增强故障测距结果准确性，且故障测距精度不受电力系统运行方式的影响，在电力系统运行方式发生较大改变时仍具有很高的测距精度。本发明方法计及线间零序互感的影响，消除了线间零序互感对故障测距精度的影响。The method of the invention only uses the electrical quantity of the single-ended single-circuit circuit, and does not need to introduce the electrical quantity of another circuit, so as to protect the secondary circuits from being independent from each other and not intersecting each other, thereby enhancing the accuracy of fault location results, and the accuracy of fault location measurement is not affected by electric power. Influenced by the operation mode of the system, it still has a high ranging accuracy when the operation mode of the power system changes greatly. The method of the invention takes into account the influence of zero-sequence mutual inductance between lines, and eliminates the influence of zero-sequence mutual inductance between lines on the accuracy of fault distance measurement.

本发明方法计算同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的相角，利用非同名相跨线接地故障点前后的故障相电压滞后同杆并架双回线路I回线路保护安装处故障相电压的相角会发生唯一一次的，由小于同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的相角突变为大于同杆并架双回线路I回线路保护安装处故障相电压领先注入非同名相跨线接地故障点零序电流的相角这一矢量相位变化特性，实现双回线路非同名相跨线接地故障的精确测距，消除了线间零序互感、过渡电阻和负荷电流对故障测距精度的影响，具有很强的抗过渡电阻和负荷电流影响的能力，保护正方向出口发生双回线路非同名相跨线接地故障时无故障测距死区。The method of the present invention calculates the phase angle of the zero-sequence current of the fault phase voltage at the I-circuit line protection installation place of the double-circuit line paralleled on the same pole and injects the phase angle of the zero-sequence current at the ground fault point of the non-identical phase across the line, and utilizes the fault phase before and after the ground fault point of the non-identical phase across the line Voltage lag The phase angle of the fault phase voltage at the installation place of the I-circuit line protection of the double-circuit line paralleled on the same pole will occur only once, and the phase angle of the fault phase voltage at the installation place of the I-circuit line protection of the double-circuit line paralleled on the same pole will be lower than that of the phase angle of the fault phase voltage at the installation place of the I-circuit line protection of the double-circuit line paralleled on the same pole. The phase angle of the zero-sequence current at the cross-line grounding fault point suddenly becomes larger than the phase angle of the phase angle of the zero-sequence current at the cross-line grounding fault point of the same-pole parallel double-circuit line I-circuit line protection installation. Change characteristics, realize accurate distance measurement of non-identical phase cross-line grounding faults of double-circuit lines, eliminate the influence of zero-sequence mutual inductance between lines, transition resistance and load current on fault location accuracy, and have strong resistance to transition resistance and load current Ability to protect the positive direction exit without fault ranging dead zone when a double-circuit line with a non-identical phase cross-line ground fault occurs.

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. The double-circuit line non-same-name-phase overline ground fault single-end distance measurement method is characterized by comprising the following sequential steps of:

(1) the protection device measures the fault phase voltage at the protection installation position of the I-loop circuit of the double-loop circuit on the same towerFault phase currentAnd zeroSequence currentWherein, phi is an I loop line A phase, an I loop line B phase or an I loop line C phase;

(2) the protection device calculates the zero sequence compensation current of the I-loop line of the double-loop line on the same tower

Wherein,

r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}});

r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}});

Z_mfor the same tower double-circuit line I circuit line and the same towerZero sequence mutual inductance between the parallel double-circuit line II circuit lines is established; z_I0Zero sequence impedance of I-loop circuit of double-loop circuit on the same tower; z_I1The positive sequence impedance of the I-loop line of the double-loop line on the same tower is obtained; phi is an I loop line A phase, an I loop line B phase or an I loop line C phase;is composed ofThe real part of (a);is composed ofAn imaginary part of (d);is composed ofThe real part of (a);is composed ofAn imaginary part of (d); j is a complex operator;

(3) the protection device calculates the fault phase voltage of the I-loop circuit protection installation position of the double-loop circuit on the same towerZero-sequence current of leading injection non-same-name-phase overline ground fault pointAngle ρ:

(4) the protection device selects the initial value of the fault distance as l_xCalculating the distance of I-loop protection installation position l of the double-loop line on the same tower_xFaulted phase voltage of a pointWherein l is the length of the I loop of the double-loop line on the same tower;

(5) protection device computingProtection installation site l for I-type circuit of leading-distance double-circuit line on same tower_xFaulted phase voltage of a pointPhase angle of

(6) Distance of failure l_xIncreasing by a fixed step length delta l, returning to the step (4), and calculating each loop on the same-tower double-loop line I in turn_xOf dotsUntil the total length of the I-loop circuit of the double-loop circuit on the same tower is reached;

(7) the protection device selects one loop of the same-tower double-loop line I_xPoint satisfiesAnd it is next to_xAt + Δ l point satisfiesThe middle position of the two points is a non-same-name phase overline grounding fault point of the double-circuit line on the same tower; wherein,Δ l is a fixed step size.