CN103762574A

CN103762574A - Double-circuit line non-same-name-phase overline grounded impedance distance protection method

Info

Publication number: CN103762574A
Application number: CN201410054043.8A
Authority: CN
Inventors: 林富洪
Original assignee: State Grid Corp of China SGCC; State Grid Fujian Electric Power Co Ltd; Putian Power Supply Co of State Grid Fujian Electric Power Co Ltd
Current assignee: State Grid Corp of China SGCC; State Grid Fujian Electric Power Co Ltd; Putian Power Supply Co of State Grid Fujian Electric Power Co Ltd
Priority date: 2014-02-18
Filing date: 2014-02-18
Publication date: 2014-04-30
Anticipated expiration: 2034-02-18
Also published as: CN103762574B

Abstract

The invention discloses a method for protecting a double-circuit line with non-identical phase-cross-line grounding impedance distance. First, measure 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 paralleled on the same pole, calculate the phase angle of the zero sequence current of the II circuit line of the double circuit line paralleled on the same pole, and calculate the parallel pole of the same pole The zero-sequence current of the second circuit of the double-circuit line, and then calculate the line fault impedance from the protection installation point of the double-circuit line I to the ground fault point, and judge whether the fault impedance amplitude of the line is less than the set impedance amplitude, if If less than, a trip signal is issued. This method only uses the electrical quantity of the single-ended single-circuit line, and does not need to introduce the electrical quantity of another circuit, and the operating performance is not affected by the operation mode of the power system. This method takes into account the influence of the zero-sequence mutual inductance between the lines and the voltage of the ground fault point, and eliminates the influence of the zero-sequence mutual inductance, transition resistance and load current on the performance of the distance protection action of the double-circuit line with the same pole and the same name. Influence.

Description

Protection method of non-identical phase cross-line grounding impedance distance for 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双回线路非同名相跨线接地阻抗距离保护方法。The invention relates to the technical field of electric power system relay protection, in particular to a method for protecting a double-circuit line with non-identical phase-cross-line grounding impedance distance protection.

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，保护出现拒动作，对电网安全稳定运行不利。Parallel double-circuit lines on the same pole have 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 power systems. There is zero-sequence mutual inductance between the double-circuit lines paralleled 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 zone on the same pole, the protection will refuse to operate, 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 there is a direct grounding fault 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.

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，提供一种动作性能不受线间零序互感、过渡电阻和负荷电流影响，适用于双回线路非同名相跨线接地故障的接地阻抗距离方法。The purpose of the present invention is to overcome the deficiencies in the prior art, to provide a grounding impedance distance method that is not affected by the zero-sequence mutual inductance between lines, transition resistance and load current, and is suitable for double-circuit line non-identical phase cross-line grounding faults .

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阻抗距离保护方法，其特征在于，包括如下依序步骤：The double-circuit line non-identical phase cross-line grounding impedance distance protection method 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为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

Among them, φ is the A phase of the I circuit line or the B phase of the I circuit line or the C phase of the I circuit line;

（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：(2) The protection device calculates the zero-sequence current phase angle α of the double-circuit line II line on the same pole parallel:

α=r₁+r₂-π-βα=r ₁ +r ₂ -π-β

其中， $r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); a_{1} = Re (\frac{{\overset{\cdot}{U}}_{Iφ}}{Z_{I 1}});$ $b_{1} = Im (\frac{{\overset{\cdot}{U}}_{Iφ}}{Z_{I 1}}); a_{2} = Re ({\overset{\cdot}{I}}_{Iφ} + \frac{Z_{10} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0}); b_{2} = Im ({\overset{\cdot}{I}}_{Iφ} + \frac{Z_{10} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0}); a_{3} = b_{3} = | \frac{Z_{m}}{{3 Z}_{I 1}} {\overset{\cdot}{I}}_{I 0} |;$ $β = Arg (\frac{Z_{m}}{{3 Z}_{I 1}} {\overset{\cdot}{I}}_{I 0});$ in, $r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); a_{1} = Re (\frac{{\overset{&Center Dot;}{u}}_{Iφ}}{Z_{I 1}});$ $b_{1} = Im (\frac{{\overset{\cdot}{u}}_{Iφ}}{Z_{I 1}}); a_{2} = Re ({\overset{\cdot}{I}}_{Iφ} + \frac{Z_{10} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0}); b_{2} = Im ({\overset{&Center Dot;}{I}}_{Iφ} + \frac{Z_{10} - Z_{I 1}}{Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0}); a_{3} = b_{3} = | \frac{Z_{m}}{{3 Z}_{I 1}} {\overset{&Center Dot;}{I}}_{I 0} |;$ $β = Arg (\frac{Z_{m}}{{3 Z}_{I 1}} {\overset{&Center Dot;}{I}}_{I 0});$

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；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;

（3）保护装置计算同杆并架双回线路II回线路的零序电流 (3) The protection device calculates the zero-sequence current of the II-circuit line of the parallel double-circuit line on the same pole

（4）保护装置计算同杆并架双回线路I回线路保护安装处到接地故障点的线路故障阻抗Z_φ：(4) The protection device calculates the line fault impedance Z _φ from the installation point of the line protection installation of the double-circuit line I to the ground fault point:

${Z Z}_{φ φ} = = \frac{{{Re Re (({\overset{\cdot \cdot}{U u}}_{Iφ Iφ})) Im Im (({\overset{\cdot \cdot}{I I}}_{I I 00} + + {\overset{\cdot \cdot}{I I}}_{II II 00})) - - Im Im (({\overset{\cdot \cdot}{U u}}_{Iφ Iφ})) Re Re (({\overset{\cdot \cdot}{I I}}_{I I 00} + + {\overset{\cdot \cdot}{I I}}_{II II 00}))}} {Z Z}_{I I 11}}{Re Re (({Z Z}_{I I 11} (({\overset{\cdot \cdot}{I I}}_{Iφ Iφ} + + \frac{{Z Z}_{I I 00} - - {Z Z}_{I I 11}}{{Z Z}_{I I 11}} {\overset{\cdot \cdot}{I I}}_{I I 00} + + \frac{{Z Z}_{m m}}{{33 Z Z}_{I I 11}} {\overset{\cdot &Center Dot;}{I I}}_{II II 00})))) Im Im (({\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + {\overset{\cdot &Center Dot;}{I I}}_{II II 00})) - - Re Re (({\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + {\overset{\cdot &Center Dot;}{I I}}_{II II 00})) Im Im (({Z Z}_{I I 11} (({\overset{\cdot &Center Dot;}{I I}}_{Iφ Iφ} + + \frac{{Z Z}_{I I 00} - - {Z Z}_{I I 11}}{{Z Z}_{I I 11}} {\overset{\cdot \cdot}{I I}}_{I I 00} + + \frac{{Z Z}_{m m}}{{33 Z Z}_{I I 11}} {\overset{\cdot \cdot}{I I}}_{II II 00}))))}$

其中，Z_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为回线路A相或I回线路B相或I回线路C相；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；Among them, 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 is the A phase of the circuit line or the B phase of the I circuit line Or phase C of the I-circuit line; 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;

（5）保护装置判断

是否成立，若成立，则判断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；l为同杆并架双回线路I回线路长度。(5) Protection device judgment

Whether it is established, if it is established, it is judged that the ground fault point is located within the setting range of the I-circuit line protection of the double-circuit line paralleled on the same pole, and the protection device sends out an action trip signal; where, l _set is the I-circuit line protection of the double-circuit line paralleled on the same pole The setting range; l is the length of the I-circuit of the parallel 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:

本发明方法首先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，计算同杆并架双回线路II回线路的零序电流相角，计算同杆并架双回线路II回线路的零序电流，然后计算同杆并架双回线路I回线路保护安装处到接地故障点的线路故障阻抗，判断线路故障阻抗幅值小于整定阻抗幅值是否成立，若成立，则发出动作跳闸信号。The method of the present invention firstly measures the fault phase voltage, fault phase current and zero-sequence current of the I-circuit line protection installation place of the double-circuit line paralleled on the same pole, calculates the phase angle of the zero-sequence current of the II-circuit line of the double-circuit line paralleled on the same pole, and calculates The zero-sequence current of the double-circuit line II on the same pole paralleled, and then calculate the line fault impedance from the installation point of the I circuit protection of the parallel double-circuit line on the same pole to the ground fault point, and judge that the amplitude of the fault impedance of the line is less than the set impedance amplitude Whether it is established, if established, an action trip signal will be issued.

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和接地故障点电压的影响，消除了线间零序互感、过渡电阻和负荷电流对同杆并架双回线路非同名相跨线接地阻抗距离保护动作性能的影响，保护范围稳定可靠。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 operation 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 lines and the voltage of the grounding fault point, and eliminates the influence of the zero-sequence mutual inductance, transition resistance and load current on the same-pole parallel double-circuit line and the non-identical phase cross-line grounding impedance distance protection action performance The impact of the protection range is stable and reliable.

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

下文通过结合附图和实施例对本发明做进一步说明。The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

图1为应用本发明的同杆并架双回线路输电系统示意图。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为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. 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 Among them, φ is the phase A of the I-circuit line, the phase B of the I-circuit line, or the 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：The protection device calculates the zero-sequence current phase angle α of the double-circuit line II line on the same pole parallel:

α=r₁+r₂-π-βα=r ₁ +r ₂ -π-β

其中， $r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); a_{1} = Re (\frac{{\overset{\cdot}{U}}_{Iφ}}{Z_{I 1}});$ $b_{1} = Im (\frac{{\overset{\cdot}{U}}_{Iφ}}{Z_{I 1}}); a_{2} = Re ({\overset{\cdot}{I}}_{Iφ} + \frac{Z_{10} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0}); b_{2} = Im ({\overset{\cdot}{I}}_{Iφ} + \frac{Z_{10} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0}); a_{3} = b_{3} = | \frac{Z_{m}}{{3 Z}_{I 1}} {\overset{\cdot}{I}}_{I 0} |;$ $β = Arg (\frac{Z_{m}}{{3 Z}_{I 1}} {\overset{\cdot}{I}}_{I 0});$ in, $r_{1} = \sin^{- 1} (\frac{a_{3} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); r_{2} = \sin^{- 1} (\frac{a_{1} b_{2} - a_{2} b_{1}}{\sqrt{{(a_{3} b_{1})}^{2} + {(a_{1} b_{3})}^{2}}}); a_{1} = Re (\frac{{\overset{\cdot}{u}}_{Iφ}}{Z_{I 1}});$ $b_{1} = Im (\frac{{\overset{&Center Dot;}{u}}_{Iφ}}{Z_{I 1}}); a_{2} = Re ({\overset{\cdot}{I}}_{Iφ} + \frac{Z_{10} - Z_{I 1}}{Z_{I 1}} {\overset{\cdot}{I}}_{I 0}); b_{2} = Im ({\overset{\cdot}{I}}_{Iφ} + \frac{Z_{10} - Z_{I 1}}{Z_{I 1}} {\overset{&Center Dot;}{I}}_{I 0}); a_{3} = b_{3} = | \frac{Z_{m}}{{3 Z}_{I 1}} {\overset{&Center Dot;}{I}}_{I 0} |;$ $β = Arg (\frac{Z_{m}}{{3 Z}_{I 1}} {\overset{&Center Dot;}{I}}_{I 0});$

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为I回线路A相或I回线路B相或I回线路C相。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;

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

保护装置计算同杆并架双回线路I回线路保护安装处到接地故障点的线路故障阻抗Z_φ：The protection device calculates the line fault impedance Z φ from the point where the line protection is installed to the ground fault point for double-circuit lines paralleled on the same pole Z _φ :

${Z Z}_{φ φ} = = \frac{{{Re Re (({\overset{\cdot \cdot}{U u}}_{Iφ Iφ})) Im Im (({\overset{\cdot \cdot}{I I}}_{I I 00} + + {\overset{\cdot \cdot}{I I}}_{II II 00})) - - Im Im (({\overset{\cdot \cdot}{U u}}_{Iφ Iφ})) Re Re (({\overset{\cdot \cdot}{I I}}_{I I 00} + + {\overset{\cdot \cdot}{I I}}_{II II 00}))}} {Z Z}_{I I 11}}{Re Re (({Z Z}_{I I 11} (({\overset{\cdot \cdot}{I I}}_{Iφ Iφ} + + \frac{{Z Z}_{I I 00} - - {Z Z}_{I I 11}}{{Z Z}_{I I 11}} {\overset{\cdot \cdot}{I I}}_{I I 00} + + \frac{{Z Z}_{m m}}{{33 Z Z}_{I I 11}} {\overset{\cdot &Center Dot;}{I I}}_{II II 00})))) Im Im (({\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + {\overset{\cdot &Center Dot;}{I I}}_{II II 00})) - - Re Re (({\overset{\cdot \cdot}{I I}}_{I I 00} + + {\overset{\cdot &Center Dot;}{I I}}_{II II 00})) Im Im (({Z Z}_{I I 11} (({\overset{\cdot &Center Dot;}{I I}}_{Iφ Iφ} + + \frac{{Z Z}_{I I 00} - - {Z Z}_{I I 11}}{{Z Z}_{I I 11}} {\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + \frac{{Z Z}_{m m}}{{33 Z Z}_{I I 11}} {\overset{\cdot &Center Dot;}{I I}}_{II II 00}))))}$

其中，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为I回线路A相或I回线路B相或I回线路C相；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；Among them, 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 is the A phase of the I-circuit line or the I-circuit line B phase or C phase of I-circuit line; 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;

保护装置判断

是否成立，若成立，则判断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；l为同杆并架双回线路I回线路长度。Protection device judgment

本发明方法首先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，计算同杆并架双回线路II回线路的零序电流相角，计算同杆并架双回线路II回线路的零序电流，然后计算同杆并架双回线路I回线路保护安装处到接地故障点的线路故障阻抗，判断线路故障阻抗幅值小于整定阻抗幅值是否成立，若成立，则发出动作跳闸信号。The method of the present invention firstly measures the fault phase voltage, fault phase current and zero-sequence current at the protection installation place of the I-circuit line of the parallel double-circuit line on the same pole, calculates the phase angle of the zero-sequence current of the II-circuit line of the double-circuit line parallel on the same pole, and calculates The zero-sequence current of the double-circuit line II on the same pole, and then calculate the line fault impedance from the protection installation point to the ground fault point of the I-circuit line of the parallel double-circuit line on the same pole, and judge that the amplitude of the fault impedance of the line is less than the set impedance amplitude Whether it is established, if established, an action trip signal will be issued.

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和接地故障点电压的影响，消除了线间零序互感、过渡电阻和负荷电流对同杆并架双回线路非同名相跨线接地阻抗距离保护动作性能的影响，保护范围稳定可靠。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 lines and the voltage of the grounding fault point, and eliminates the influence of the zero-sequence mutual inductance, transition resistance and load current on the double-circuit line with the same pole and the double-circuit line with the same name. The impact of the protection range is stable and reliable.

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 method for protection of double-circuit lines with non-identical phase-cross-line grounding impedance distance, including the following sequential steps:

(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

(2) The protection device calculates the zero-sequence current phase angle α of the double-circuit line II line on the same pole parallel:

α=r ₁ +r ₂ -π-β

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}}_{Iφ}}{Z_{I 1}});

{b b}_{11} = = Im Im ((\frac{{\overset{\cdot &Center Dot;}{U u}}_{Iφ Iφ}}{{Z Z}_{I I 11}}));; {a a}_{22} = = Re Re (({\overset{\cdot &Center Dot;}{I I}}_{Iφ Iφ} + + \frac{{Z Z}_{1010} - - {Z Z}_{I I 11}}{{Z Z}_{I I 11}} {\overset{\cdot &Center Dot;}{I I}}_{I I 00}));; {b b}_{22} = = Im Im (({\overset{\cdot \cdot}{I I}}_{Iφ Iφ} + + \frac{{Z Z}_{1010} - - {Z Z}_{I I 11}}{{Z Z}_{I I 11}} {\overset{\cdot &Center Dot;}{I I}}_{I I 00}));; {a a}_{33} = = {b b}_{33} = = | | \frac{{Z Z}_{m m}}{{33 Z Z}_{I I 11}} {\overset{\cdot &Center Dot;}{I I}}_{I I 00} | |;;

β β = = Arg Arg ((\frac{{Z Z}_{m m}}{{33 Z Z}_{I I 11}} {\overset{\cdot &Center Dot;}{I I}}_{I I 00}));;

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 paralleled on the same pole; φ is the A phase of the I-circuit line or the B-phase of the I-circuit line or the C-phase of the I-circuit line;

(3) The protection device calculates the zero-sequence current of the II-circuit line of the parallel double-circuit line on the same pole

(4) The protection device calculates the line fault impedance Z _φ from the installation point of the line protection installation of the double-circuit line I to the ground fault point:

{Z Z}_{φ φ} = = \frac{{{Re Re (({\overset{\cdot &Center Dot;}{U u}}_{Iφ Iφ})) Im Im (({\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + {\overset{\cdot &Center Dot;}{I I}}_{II II 00})) - - Im Im (({\overset{\cdot &Center Dot;}{U u}}_{Iφ Iφ})) Re Re (({\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + {\overset{\cdot &Center Dot;}{I I}}_{II II 00}))}} {Z Z}_{I I 11}}{Re Re (({Z Z}_{I I 11} (({\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 &Center Dot;}{I I}}_{I I 00} + + \frac{{Z Z}_{m m}}{{33 Z Z}_{I I 11}} {\overset{\cdot &Center Dot;}{I I}}_{II II 00})))) Im Im (({\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + {\overset{\cdot &Center Dot;}{I I}}_{II II 00})) - - Re Re (({\overset{\cdot &Center Dot;}{I I}}_{I I 00} + + {\overset{\cdot \cdot}{I I}}_{II II 00})) Im Im (({Z Z}_{I I 11} (({\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 \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}))))}

Among them, 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= Phase A of the I-circuit line or B of the I-circuit line phase or C phase of I-circuit line; 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;

(5) Protection device judgment