CN104953563A

CN104953563A - Double-circuit non-homonymous phase overline grounding fault relay protection method based on perceptual pressure drop progressive decreasing characteristics

Info

Publication number: CN104953563A
Application number: CN201510336610.3A
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: 2015-06-17
Filing date: 2015-06-17
Publication date: 2015-09-30

Abstract

The invention discloses a relay protection method for non-identical phase cross-line grounding faults of a double-circuit line based on the inductive voltage drop decreasing characteristic. The method of the present invention calculates the zero-sequence compensation current of the I-circuit line of the parallel double-circuit line on the same pole, calculates the imaginary part of the voltage drop from the non-identical phase cross-line grounding fault point to the I-circuit line protection installation of the double-circuit line on the same pole, and calculates The imaginary part of the voltage drop from the protection setting range to the I-circuit line protection installation place of the parallel double-circuit line on the same pole, etc., and then use the non-identical phase cross-line grounding fault point to the I-circuit line protection installation place of the parallel double-circuit line on the same pole The imaginary part of the voltage drop and the imaginary part of the voltage drop from the setting range of the protection to the protection installation of the I-circuit line of the double-circuit line on the same pole constitute the single-end electrical quantity relay protection criterion for the non-identical phase cross-line grounding fault of the double-circuit line, which eliminates the The influence of zero-sequence mutual inductance between lines, transition resistance and load current on the performance of protection action is eliminated, and it has a strong ability to resist the influence of transition resistance and load current.

Description

Relay protection method for non-identical phase-cross-line grounding faults of double-circuit lines based on inductive voltage drop decreasing characteristics

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感性压降递减特性双回线路非同名相跨线接地故障继电保护方法。The invention relates to the technical field of relay protection for electric power systems, in particular to a relay protection method for double-circuit line non-identical phase cross-line grounding faults based on the inductive voltage drop decreasing characteristic.

背景技术Background technique

同杆并架双回线路具有占地面积少、造价成本低，连接电网运行稳定可靠，已成为电力系统一种常见输电线路连接方式。同杆并架双回线路线间存在零序互感，零序互感对零序补偿系数产生影响，进而产生附加阻抗，因零序互感引起的附加阻抗会导致保护装置测量到的故障阻抗大于实际故障阻抗，造成同杆并架双回线路保护区内靠近保护整定范围处发生接地故障时，保护出现误动作，对电网安全稳定运行不利。The double-circuit line paralleled on the same pole has a small footprint, low cost, and stable and reliable operation when connected to the grid. It has become a common transmission line connection method in the power system. There is zero-sequence mutual inductance between double-circuit lines on the same pole, and the zero-sequence mutual inductance affects the zero-sequence compensation coefficient, thereby generating additional impedance. The additional impedance caused by the zero-sequence mutual inductance will cause the fault impedance measured by the protection device to be greater than the actual fault When a ground fault occurs near the protection setting range in the double-circuit line protection area of the same pole, the protection will malfunction, which is not good for the safe and stable operation of the power grid.

同杆并架双回线路即使发生经杆塔直接接地故障，在土壤电阻率较低的地区过渡电阻也在10Ω附近；在电阻率较高的地方过渡电阻可达30Ω，或甚至更高。过渡电阻不为零使得保护装置计算得到的故障阻抗除包含反应真实故障距离的故障阻抗分量外，还包含了因过渡电阻而产生的附加阻抗。过渡电阻产生的附加阻抗呈阻感性或呈阻容性容易造成接地阻抗距离保护拒动或稳态超越。保护误动或拒动，会给电力系统安全运行带来重大的损失，甚至有可能会威胁到电力系统的稳定性。Even if a direct grounding fault occurs on the double-circuit lines paralleled on the same pole, the transition resistance is around 10Ω in areas with low soil resistivity; the transition resistance can reach 30Ω or even higher in areas with high resistivity. The non-zero transition resistance makes the fault impedance calculated by the protection device not only include the fault impedance component reflecting the real fault distance, but also include the additional impedance caused by the transition resistance. The additional impedance generated by the transition resistance is resistive-inductive or resistive-capacitive, which may easily cause the grounding impedance distance protection to refuse to operate or exceed the steady state. Malfunction or refusal to operate the protection will bring significant losses to the safe operation of the power system, and may even threaten the stability of the power system.

现有同杆并架双回线路接地距离保护的动作特性圆边界经过坐标原点，由于坐标原点位于动作特性圆边界上，保护正向出口接地故障时保护存在死区，且随着过渡电阻和负荷电流增大，保护正向出口死区越大。由于坐标原点位于动作特性圆边界上，保护反方向出口接地故障存在误动的可能，且过渡电阻越大，保护反方向出口接地故障时保护越容易误动作。The circle boundary of the action characteristics of the existing double-circuit line grounding distance protection on the same pole passes through the origin of the coordinates. Since the origin of the coordinates is located on the circle boundary of the action characteristics, there is a dead zone in the protection when the forward exit is grounded. As the current increases, the dead zone at the forward exit of the protection increases. Since the origin of the coordinates is located on the boundary of the action characteristic circle, there is a possibility of misoperation due to a ground fault at the outlet in the opposite direction of protection, and the larger the transition resistance is, the easier it is for the protection to malfunction when the ground fault occurs at the outlet in the opposite direction.

由于同杆并架双回线路线间存在很强的零序互感，现有接地距离保护无法获取另一回线路的零序电流，算法模型中无法消除线间零序互感的影响，受线间零序互感的影响，传统单相接地距离保护应用于同杆并架双回线路时其保护范围将大大扩大，在保护整定范围处故障常常存在稳态超越，使得保护区外故障时容易发生误动作，容易造成潮流大转移，引发大面积停电事故发生。Due to the strong zero-sequence mutual inductance between double-circuit lines on the same pole, the existing grounding distance protection cannot obtain the zero-sequence current of the other circuit, and the algorithm model cannot eliminate the influence of zero-sequence mutual inductance between lines. Due to the influence of zero-sequence mutual inductance, when the traditional single-phase grounding distance protection is applied to parallel double-circuit lines on the same pole, its protection range will be greatly expanded. Faults in the protection setting range often have steady-state overshoots, which makes it easy to cause errors when faults outside the protection zone Actions are likely to cause a large shift in power flow and cause large-scale power outages.

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，提供一种基于感性压降递减特性双回线路非同名相跨线接地故障继电保护方法，该方法利用非同名相跨线接地故障点到同杆并架双回线路I回线路保护安装处的电压降虚部与保护整定范围处到同杆并架双回线路I回线路保护安装处的电压降虚部构成单端电气量继电保护判据，消除了线间零序互感、过渡电阻和负荷电流对保护动作性能的影响，具有很强的抗过渡电阻和负荷电流影响的能力。The purpose of the present invention is to overcome the deficiencies in the prior art, and to provide a method for relay protection for double-circuit line non-identical phase-cross-line ground faults based on the inductive voltage drop characteristic. The imaginary part of the voltage drop at the installation place of the I-circuit line protection of the pole-parallel double-circuit line and the imaginary part of the voltage drop from the protection setting range to the installation place of the I-circuit line protection of the parallel-pole double-circuit line constitute the single-ended electrical quantity relay protection judgment According to the data, it eliminates the influence of zero-sequence mutual inductance between lines, transition resistance and load current on the protection action performance, and has a strong ability to resist the influence of transition resistance and load current.

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:

基于感性压降递减特性双回线路非同名相跨线接地故障继电保护方法，其特征在于，包括如下依序步骤：The method for relay protection of non-identical phase-cross-line grounding faults of double-circuit lines based on the inductive voltage drop decreasing characteristic 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、I回线路B相、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, I loop line B phase, I loop line C phase;

(2)保护装置计算同杆并架双回线路II回线路的零序电流相角α＝r₁+r₂-π-β；(2) The protection device calculates the zero-sequence current phase angle α=r ₁ +r ₂ -π-β of the double-circuit line II line on the same pole;

其中， $r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); a_{1} = Re (\frac{{\overset{\cdot}{U}}_{I φ}}{Z_{I 1}}); b_{1} = Im (\frac{{\overset{\cdot}{U}}_{I φ}}{Z_{I 1}});$ $a_{2} = Re ({\overset{\cdot}{I}}_{I φ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0}); b_{2} = I m ({\overset{\cdot}{I}}_{I φ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0}); a_{3} = b_{3} = | \frac{Z_{m}}{3 Z_{I 1}} {\overset{\cdot}{I}}_{I 0} |; β = A r g (\frac{Z_{m}}{3 Z_{I 1}} {\overset{\cdot}{I}}_{I 0});$ 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、I回线路B相、I回线路C相；为的实部；为的虚部；为的实部；为的虚部；为的幅值；为的相角；为的反正弦函数值；为的反正弦函数值。in, $r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); a_{1} = Re (\frac{{\overset{&Center Dot;}{u}}_{I φ}}{Z_{I 1}}); b_{1} = Im (\frac{{\overset{&Center Dot;}{u}}_{I φ}}{Z_{I 1}});$ $a_{2} = Re ({\overset{\cdot}{I}}_{I φ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0}); b_{2} = I m ({\overset{&Center Dot;}{I}}_{I φ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0}); a_{3} = b_{3} = | \frac{Z_{m}}{3 Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0} |; β = A r g (\frac{Z_{m}}{3 Z_{I 1}} {\overset{\cdot}{I}}_{I 0});$ 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 parallel double-circuit line on the same pole; φ=I-circuit line A phase, I-circuit line B phase, and 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 for the amplitude of for the phase angle; for The arcsine function value of ; for The arcsine function value of .

(3)保护装置计算同杆并架双回线路II回线路的零序电流其中，j为复数算子；(3) The protection device calculates the zero-sequence current of the II-circuit line of the parallel double-circuit line on the same pole Among them, j is a complex number operator;

(4)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 (4) The protection device calculates the zero-sequence compensation current of the I-circuit line of the parallel double-circuit line on the same pole

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

(5)保护装置计算非同名相跨线接地故障点到同杆并架双回线路I回线路保护安装处的电压降的虚部 $Im (Δ \overset{\cdot}{U}) = \frac{Re ({\overset{\cdot}{U}}_{I φ}) Im ({\overset{\cdot}{I}}_{I 0} + {\overset{\cdot}{I}}_{I I 0}) - Im ({\overset{\cdot}{U}}_{I φ}) Re ({\overset{\cdot}{I}}_{I 0} + {\overset{\cdot}{I}}_{I I 0})}{R (\frac{Z_{I 1}}{l} Δ \overset{\cdot}{I}) Im ({\overset{\cdot}{I}}_{I 0} + {\overset{\cdot}{I}}_{I I 0}) - I m (\frac{Z_{I 1}}{l} Δ \overset{\cdot}{I}) Re ({\overset{\cdot}{I}}_{I 0} + {\overset{\cdot}{I}}_{I I 0})} Im (\frac{Z_{I 1}}{l} Δ \overset{\cdot}{I});$ 其中，l为同杆并架双回线路I回线路长度；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、I回线路B相、I回线路C相；为的实部；为的虚部；为的实部；为的虚部；为的实部；为的虚部；(5) The protection device calculates the voltage drop from the grounding fault point of the non-identical phase across the line to the protective installation of the I-circuit line of the parallel double-circuit line on the same pole the imaginary part of $Im (Δ \overset{\cdot}{u}) = \frac{Re ({\overset{\cdot}{u}}_{I φ}) Im ({\overset{&Center Dot;}{I}}_{I 0} + {\overset{&Center Dot;}{I}}_{I I 0}) - Im ({\overset{\cdot}{u}}_{I φ}) Re ({\overset{\cdot}{I}}_{I 0} + {\overset{&Center Dot;}{I}}_{I I 0})}{R (\frac{Z_{I 1}}{l} Δ \overset{&Center Dot;}{I}) Im ({\overset{&Center Dot;}{I}}_{I 0} + {\overset{\cdot}{I}}_{I I 0}) - I m (\frac{Z_{I 1}}{l} Δ \overset{\cdot}{I}) Re ({\overset{\cdot}{I}}_{I 0} + {\overset{\cdot}{I}}_{I I 0})} Im (\frac{Z_{I 1}}{l} Δ \overset{&Center Dot;}{I});$ Among them, l is the length of the I circuit of the parallel double circuit line on the same pole; Z _I1 is the positive sequence impedance of the I circuit of the parallel double circuit line on the same pole; φ=I circuit A phase, I circuit B phase, 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 for the real part of for the imaginary part of

(6)保护装置判断是否成立，若成立，则判断非同名相跨线接地故障点位于同杆并架双回线路I回线路保护整定范围之内，发出动作跳闸信号；其中，l_set为同杆并架双回线路I回线路保护整定范围，取0.85倍同杆并架双回线路I回线路长度。(6) Protection device judgment Whether it is established, if it is established, it is judged that the non-identical phase cross-line grounding fault point is within the protection setting range of the I-circuit line of the parallel double-circuit line on the same pole, and an action trip signal is issued; among them, l _set is the parallel double-circuit line on the same pole For the setting range of I-circuit line protection, take 0.85 times the length of the I-circuit line of the double-circuit line on the same pole.

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，动作性能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具有很强的适应能力。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保护动作性能的影响。本发明方法采用集中参数建模，利用非同名相跨线接地故障点到同杆并架双回线路I回线路保护安装处的电压降虚部与保护整定范围处到同杆并架双回线路I回线路保护安装处的电压降虚部构成双回线路非同名相跨线接地故障单端电气量继电保护判据，消除了过渡电阻和负荷电流对保护动作性能的影响，具有很强的抗过渡电阻和负荷电流影响的能力，适用于双回线路非同名相跨线接地故障的整个故障过程的继电保护。The method of the present invention only uses the electrical quantity of the single-ended single-circuit line, and does not need to introduce the electrical quantity of another circuit. The operating performance is not affected by the operation mode of the power system, and it has strong adaptability when the operation mode of the power system changes greatly. ability. The method of the invention takes into account the influence of the zero-sequence mutual inductance between the lines, and eliminates the influence of the zero-sequence mutual inductance between the lines on the protection action performance. The method of the present invention adopts centralized parameter modeling, and utilizes the imaginary part of the voltage drop and the protection setting range of the voltage drop from the non-identical phase cross-line grounding fault point to the parallel double-circuit line on the same pole and the protection installation place of the double-circuit line to the parallel double-circuit line on the same pole The imaginary part of the voltage drop at the installation place of the I-circuit line protection constitutes the single-ended electrical quantity relay protection criterion for the non-identical phase cross-line grounding fault of the double-circuit line, which eliminates the influence of the transition resistance and load current on the protection action performance, and has a strong The ability to resist the influence of transition resistance and load current is suitable for the relay protection of the entire fault process of double-circuit line non-identical phase cross-line ground fault.

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，m、n为同杆并架双回线路的两端编号。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、I回线路B相、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 Figure 1, PT is a voltage transformer, CT is a current transformer, and m and n are the numbers of the two ends of the double-circuit line on the same pole. 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=phase A of the I-circuit line, phase B of the I-circuit line, and phase C of the I-circuit line.

保护装置计算同杆并架双回线路II回线路的零序电流相角α＝r₁+r₂-π-β；The protection device calculates the zero-sequence current phase angle α=r ₁ +r ₂ -π-β of the double-circuit line II line on the same pole;

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、I回线路B相、I回线路C相； $a_{3} = b_{3} = | \frac{Z_{m}}{3 Z_{I 1}} {\overset{\cdot}{I}}_{I 0} |,$ 为的幅值； $β = Arg (\frac{Z_{m}}{3 Z_{I 1}} {\overset{\cdot}{I}}_{I 0}),$ 为的相角；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 double-circuit line I circuit on the same pole; φ=I circuit A phase, I circuit B phase, I circuit C phase; $a_{3} = b_{3} = | \frac{Z_{m}}{3 Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0} |,$ for the amplitude of $β = Arg (\frac{Z_{m}}{3 Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0}),$ for the phase angle;

$a_{2} = Re ({\overset{\cdot}{I}}_{I φ} + \frac{Z_{I 0} - Z_{I 0}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0}),$ 为的实部； $b_{2} = I m ({\overset{\cdot}{I}}_{I φ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0}),$ 为的虚部； $a_{1} = Re (\frac{{\overset{\cdot}{U}}_{I φ}}{Z_{I 1}}),$ 为的实部； $b_{1} = I m (\frac{{\overset{\cdot}{U}}_{I φ}}{Z_{I 1}}),$ 为的虚部；r₁、r₂为中间变量，无物理意义，且 $r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}), r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}})$ 为的反正弦函数值；为的反正弦函数值。 $a_{2} = Re ({\overset{\cdot}{I}}_{I φ} + \frac{Z_{I 0} - Z_{I 0}}{Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0}),$ for the real part of $b_{2} = I m ({\overset{\cdot}{I}}_{I φ} + \frac{Z_{I 0} - Z_{I 1}}{Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0}),$ for the imaginary part of $a_{1} = Re (\frac{{\overset{\cdot}{u}}_{I φ}}{Z_{I 1}}),$ for the real part of $b_{1} = I m (\frac{{\overset{&Center Dot;}{u}}_{I φ}}{Z_{I 1}}),$ for The imaginary part of ; r ₁ , r ₂ are intermediate variables with no physical meaning, and $r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}), r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}})$ for The arcsine function value of ; for The arcsine function value of .

保护装置计算同杆并架双回线路II回线路的零序电流其中，j为复数算子。The protection device calculates the zero-sequence current of the double-circuit line II on the same pole Among them, j is a complex number 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

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

保护装置计算非同名相跨线接地故障点到同杆并架双回线路I回线路保护安装处的电压降的虚部：The protection device calculates the voltage drop from the grounding fault point of the non-identical phase across the line to the protection installation point of the I-circuit line of the parallel double-circuit line on the same pole The imaginary part of :

$Im Im ((Δ Δ \overset{\cdot &Center Dot;}{U u})) = = \frac{Re Re (({\overset{\cdot &Center Dot;}{U u}}_{I I φ φ})) Im Im (({\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + {\overset{\cdot \cdot}{I I}}_{I I I I 00})) - - I I m m (({\overset{\cdot &Center Dot;}{U u}}_{I I φ φ})) Re Re (({\overset{\cdot \cdot}{I I}}_{I I 00} + + {\overset{\cdot &Center Dot;}{I I}}_{I I I I 00}))}{R R ((\frac{{Z Z}_{I I 11}}{l l} Δ Δ \overset{\cdot &Center Dot;}{I I})) Im Im (({\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + {\overset{\cdot &Center Dot;}{I I}}_{I I I I 00})) - - Im Im ((\frac{{Z Z}_{I I 11}}{l l} Δ Δ \overset{\cdot &Center Dot;}{I I})) Re Re (({\overset{\cdot \cdot}{I I}}_{I I 00} + + {\overset{\cdot &Center Dot;}{I I}}_{I I I I 00}))} Im Im ((\frac{{Z Z}_{I I 11}}{l l} Δ Δ \overset{\cdot &Center Dot;}{I I}))$

其中，l为同杆并架双回线路I回线路长度；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、I回线路B相、I回线路C相；为的实部；为的虚部；为的实部；为的虚部；为的实部；为的虚部。Among them, l is the length of the I circuit of the parallel double circuit line on the same pole; Z _I1 is the positive sequence impedance of the I circuit of the parallel double circuit line on the same pole; φ=I circuit A phase, I circuit B phase, 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 for the real part of for the imaginary part of .

若非同名相跨线接地故障点位于同杆并架双回线路I回线路保护整定范围之内，则非同名相跨线接地故障点到同杆并架双回线路I回线路保护安装处的电压降虚部小于保护整定范围处到同杆并架双回线路I回线路保护安装处的电压降虚部；若非同名相跨线接地故障点位于同杆并架双回线路I回线路保护整定范围之外，则非同名相跨线接地故障点到同杆并架双回线路I回线路保护安装处的电压降虚部大于保护整定范围处到同杆并架双回线路I回线路保护安装处的电压降虚部；根据此特性提出双回线路非同名相跨线接地故障的单端电气量继电保护判据如下：If the ground fault point of the non-identical phase across the line is within the setting range of the I-circuit line protection of the parallel double-circuit line on the same pole, the voltage from the ground fault point of the non-identical phase across the line to the I-circuit line protection installation of the parallel double-circuit line on the same pole The imaginary part of the drop is less than the imaginary part of the voltage drop from the protection setting range to the I-circuit line protection installation of the double-circuit line on the same pole; In addition, the imaginary part of the voltage drop from the non-identical phase cross-line grounding fault point to the I-circuit line protection installation of the parallel double-circuit line on the same pole is greater than the protection setting range to the I-circuit line protection installation of the parallel double-circuit line on the same pole The imaginary part of the voltage drop; according to this characteristic, the single-ended electrical quantity relay protection criterion for double-circuit line non-identical phase cross-line ground fault is proposed as follows:

判断是否成立，若成立，则判断非同名相跨线接地故障点位于同杆并架双回线路I回线路保护整定范围之内，保护装置发出动作跳闸信号；其中，l_set为同杆并架双回线路I回线路保护整定范围，取0.85倍同杆并架双回线路I回线路长度。judge Whether it is established, if it is established, it is judged that the non-identical phase cross-line grounding fault point is within the protection setting range of the I- _circuit line of the parallel double-circuit line on the same pole, and the protection device sends out an action trip signal; For the setting range of circuit I circuit protection, take 0.85 times the length of the circuit I of the double circuit line paralleled on the same pole.

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，动作性能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具有很强的适应能力。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保护动作性能的影响。本发明方法采用集中参数建模，利用非同名相跨线接地故障点到同杆并架双回线路I回线路保护安装处的电压降虚部与保护整定范围处到同杆并架双回线路I回线路保护安装处的电压降虚部构成单端电气量继电保护判据，消除了过渡电阻和负荷电流对保护动作性能的影响，具有很强的抗过渡电阻和负荷电流影响的能力，适用于双回线路非同名相跨线接地故障的整个故障过程的继电保护。The method of the present invention only uses the electrical quantity of the single-ended single-circuit line, and does not need to introduce the electrical quantity of another circuit. The operating performance is not affected by the operation mode of the power system, and it has strong adaptability when the operation mode of the power system changes greatly. ability. The method of the invention takes into account the influence of the zero-sequence mutual inductance between the lines, and eliminates the influence of the zero-sequence mutual inductance between the lines on the protection action performance. The method of the present invention adopts centralized parameter modeling, and utilizes the imaginary part of the voltage drop and the protection setting range of the voltage drop from the non-identical phase cross-line grounding fault point to the parallel double-circuit line on the same pole and the protection installation place of the double-circuit line to the parallel double-circuit line on the same pole The imaginary part of the voltage drop at the installation place of the I-circuit line protection constitutes the single-ended electrical quantity relay protection criterion, which eliminates the influence of transition resistance and load current on the protection action performance, and has a strong ability to resist the influence of transition resistance and load current. It is suitable for the relay protection of the whole fault process of the non-identical phase cross-line grounding fault of the double-circuit line.

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 relay protection method for the non-same-name-phase overline ground fault of the double-circuit line based on the inductive voltage drop degressive characteristic is characterized by comprising the following steps in sequence:

(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 zero sequence currentWherein phi is an I loop circuit A phase, an I loop circuit B phase and an I loop circuit C phase;

(2) the protection device calculates the zero sequence current phase angle alpha of the II-loop circuit of the double-loop circuit on the same tower as r₁+r₂-π-β；

Wherein,

Z_mzero sequence mutual inductance between the circuit I of the double-circuit line on the same tower and the circuit II of the double-circuit line on the same tower is achieved; 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 and 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);is composed ofThe amplitude of (d);is composed ofThe phase angle of (d);is composed ofThe arcsine function value of (1);is composed ofThe arcsine function value of (a).

(3) The protection device calculates the zero sequence current of the II-loop line of the double-loop line on the same towerWherein j is a complex operator;

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

(5) The protection device calculates the voltage drop from the non-same-name phase overline ground fault point to the protection installation position of the I-loop circuit of the same-tower double-loop circuitImaginary part of

Wherein l is the length of the I loop of the double-loop line 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 and 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);is composed ofThe real part of (a);is composed ofAn imaginary part of (d);

(6) protection device judgmentIf yes, judging that the non-same-name phase overline ground fault point is located within the I-loop circuit protection setting range of the double-loop circuit on the same tower, and sending an action trip signal; wherein l_setFor double-circuit line I loop on the same towerAnd (4) taking 0.85 time of the I-loop circuit length of the double-loop circuit on the same tower in the circuit protection setting range.