CN102904227A

CN102904227A - A phase difference protection method for double circuit lines on the same pole based on six-sequence components

Info

Publication number: CN102904227A
Application number: CN2012103794598A
Authority: CN
Inventors: 张艳霞; 邓中原; 刘书占
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2012-09-29
Filing date: 2012-09-29
Publication date: 2013-01-30

Abstract

The invention belongs to the field of relay protection of a power system, and relates to a six-sequence component-based double circuit lines on same pole phase difference protection method. The method comprises the following steps of: (1) acquiring six currents on each side of double-circuit lines by using current transformers at the protective installation positions on m and n sides of a circuit; (2) converting the six currents on each side of the double-circuit lines into six sequence current components by six-sequence transformation; (3) respectively subtracting corresponding sequence component a week before a fault from the same positive sequence components on the two sides to obtain respective same positive sequence fault components; (4) constructing composite currents by using the same positive sequence fault components, reverse positive sequence components and the same negative sequence components of the six sequence current components, and respectively solving the phase angles of the composite currents on the two sides; and (5) setting a phase difference protection action angle as Phi OP, determining that an internal fault exists if the absolute value of the difference between the phase angles of composite currents on the two sides of the circuit is smaller than the action angle, and otherwise, judging to be an external fault. By the method, a fault, particularly a cross-line fault, can be judged very well; and the method is easy to implement.

Description

A phase difference protection method for double circuit lines on the same pole based on six-sequence components

技术领域 technical field

本发明涉及电力系统的继电保护领域，具体涉及一种基于六序分量的同杆双回线相差保护的新方法。The invention relates to the field of relay protection of electric power systems, in particular to a new method for phase difference protection of double circuit lines on the same pole based on six-sequence components.

背景技术 Background technique

在220kV及以上电压等级的同杆双回线路上，保护配置一般以分相电流差动作为第一主保护，方向或距离纵联作为第二主保护，三段式距离保护作为后备保护^[1]。但是，同杆双回线的分相电流差动保护需要分别比较六条线路上的两端电流幅值，占用通道数较多，使其因通道故障而降低可靠性的可能性加大，且价格昂贵。作为第二主保护的方向或距离纵联保护受电力系统振荡的影响，在接地故障时反应过渡电阻的能力受接地点位置、故障前负荷电流等因素的影响。On double-circuit lines on the same pole with a voltage level of 220kV and above, the protection configuration generally uses the phase-separated current difference action as the first main protection, the direction or distance longitudinal connection as the second main protection, and the three-stage distance protection as the backup protection ^{[1 ]} . However, the phase-separated current differential protection of the double-circuit line on the same pole needs to compare the current amplitudes at both ends of the six lines, which occupies a large number of channels, making it more likely that the reliability will be reduced due to channel failure, and the price expensive. As the second main protection, the direction or distance longitudinal protection is affected by the power system oscillation, and the ability to respond to the transition resistance in the event of a ground fault is affected by factors such as the position of the ground point and the load current before the fault.

纵联电流相位差动保护比较被保护线路两端的电流相位，与故障电流的幅值无关，不受电力系统振荡影响，能够允许较大的过渡电阻，并且构成简单，工作可靠。三相输电线路的纵联相差保护采用复合电流

作为保护的操作电流，将两侧操作电流的相角差作为保护动作的判据，其优点是把三相电流作为整体考虑，节约传播通道。当把同杆双回线看做两个三相输电线路时，该原理可直接用于同杆双回线路上作为第二主保护，但对同杆双回线的跨线故障难以正确判定^[2、3]。The longitudinal current phase differential protection compares the current phase at both ends of the protected line, has nothing to do with the magnitude of the fault current, is not affected by the power system oscillation, can allow a large transition resistance, and has a simple structure and reliable operation. The longitudinal phase difference protection of three-phase transmission lines adopts composite current

As the operating current of the protection, the phase angle difference of the operating current on both sides is used as the criterion of the protection action. The advantage is that the three-phase current is considered as a whole and the transmission channel is saved. When the double-circuit line on the same pole is regarded as two three-phase transmission lines, this principle can be directly used on the double-circuit line on the same pole as the second main protection, but it is difficult to correctly determine the cross-line fault of the double-circuit line on the same pole ^{[ 2, 3]} .

因此，有必要提出一种新的保护方法，作为同杆双回线路的第二主保护，既能减少占用通道数量，又能提高对故障类型的判别能力。Therefore, it is necessary to propose a new protection method as the second main protection of double-circuit lines on the same pole, which can not only reduce the number of occupied channels, but also improve the ability to distinguish fault types.

参考文献references

[1]贺家李，宋从矩，电力系统继电保护原理（增订版），北京：中国电力出版社，2007.[1] He Jiali, Song Congju, Principles of Power System Relay Protection (Updated Edition), Beijing: China Electric Power Press, 2007.

[2]葛耀中，新型继电保护与故障测距原理与技术，西安交通大学出版社，1996[2] Ge Yaozhong, Principle and Technology of New Relay Protection and Fault Location, Xi'an Jiaotong University Press, 1996

[3]计策,张艳霞,杨钢.相差高频保护中操作元件比相动作判据的研究，电网技术，2006，30（4）：55-59[3] Ji Ce, Zhang Yanxia, Yang Gang. Research on the Criterion of Phase Comparison Action of Operating Elements in Phase Difference High Frequency Protection, Power Grid Technology, 2006, 30(4): 55-59

[4]张艳霞，王艳，伍仕，等，基于六序分量法的六相输电系统故障选相，电力系统自动化，2009，33(24)：1-5[4] Zhang Yanxia, Wang Yan, Wu Shi, etc., Fault Phase Selection of Six-phase Transmission System Based on Six-sequence Component Method, Electric Power System Automation, 2009, 33(24): 1-5

发明内容 Contents of the invention

本发明的目的是克服现有技术的上述不足，提供一种针对同杆双回线的相差保护方法，在各种故障类型下，能更好地判定故障，特别是跨线故障，且易于实现。本发明的技术方案如下：The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art, and provide a phase difference protection method for double-circuit lines on the same pole, which can better determine faults under various fault types, especially cross-line faults, and is easy to implement . Technical scheme of the present invention is as follows:

一种基于六序分量的同杆双回线相差保护方法，包括下列步骤：A method for phase difference protection of double circuit lines on the same pole based on six-sequence components, comprising the following steps:

（1）通过线路m、n两侧保护安装处的电流互感器采集双回线每侧六个电流；(1) Collect six currents on each side of the double-circuit line through the current transformers at the protective installations on both sides of the line m and n;

（2）分别将双回线每侧六个电流通过六序变换转化为六个序电流分量：

和

分别为m侧的同零序分量、同正序分量、同负序分量、反零序分量、反正序分量和反负序分量；

和

分别为n侧的同零序分量、同正序分量、同负序分量、反零序分量、反正序分量和反负序分量；(2) Transform the six currents on each side of the double-circuit line into six sequence current components through six-sequence transformation:

and

are the same zero-sequence component, same positive sequence component, same negative sequence component, anti-zero sequence component, anti-sequence component and anti-negative sequence component of side m, respectively;

and

Respectively, the same zero-sequence component, same positive sequence component, same negative sequence component, anti-zero sequence component, anti-sequence component and anti-negative sequence component of side n;

（3）对m同正序分量

和n两侧的同正序分量

分别减去故障前一周对应的该序分量，得到同正序故障分量 (3) Same positive sequence component for m

and the same positive sequence components on both sides of n

Subtract the sequence component corresponding to the week before the fault respectively to obtain the same positive sequence fault component

（4）利用

和

分别构成的m侧的复合电流和n侧的复合电流

分别求得两侧复合电流的相角；(4) use

and

Recombination currents on the side m and the recombination current on the n-side

Obtain the phase angle of the composite current on both sides respectively;

（5）设相差保护的动作角为

若线路两侧复合电流的相角之差的绝对值小于则判定为内部故障，否则判为外部故障。(5) Let the action angle of the phase difference protection be

If the absolute value of the phase angle difference of the composite current on both sides of the line is less than If it is judged as an internal fault, otherwise it is judged as an external fault.

作为优选实施方式，

l为被保护线路长度，单位：km；K_F1取2～4，K_T2取19～21。As a preferred embodiment,

l is the length of the protected line, unit: km; K _F1 takes 2~4, and K _T2 takes 19~21.

本发明的有益效果如下：The beneficial effects of the present invention are as follows:

1、同杆双回线的相差保护新方法将同杆双回线六个电流作为整体考虑，不受系统振荡的影响，节约了通道数量，提高保护可靠性，简化了保护的配置。1. The new method of phase difference protection for double circuit lines on the same pole considers the six currents of double circuit lines on the same pole as a whole, which is not affected by system oscillation, saves the number of channels, improves protection reliability, and simplifies protection configuration.

2、新方法不受负荷电流影响，耐渡电阻能力强，受电容电流影响小。2. The new method is not affected by load current, has strong ability to withstand resistance, and is less affected by capacitive current.

3、新方法动作原理简单明确，易于在微机保护中实现；3. The action principle of the new method is simple and clear, and it is easy to realize in the microcomputer protection;

附图说明 Description of drawings

图1双回线系统示意图。Figure 1 Schematic diagram of the double circuit system.

具体实施方式 Detailed ways

如图1所示的完全换位双回线的阻抗矩阵是满阵，求解困难。六序变换^[2]的实质是解耦双回线的线间互感和单回线的相间互感。先利用式（1）的P矩阵对完全换位双回线的各相量进行变换，其实质是将六相电流分为两部分：三个同向量（穿越量，以T表示）和三个反向量(环流量，以F表示)。由于三个同向量电流互差120°，在反向量回路中产生的感应电势互相抵消，而三个自成回路的反向穿越量电流各自在同向量回路的感应电势也相互抵消，因此同、反向量回路之间没有了互感，由此把双回线路解耦成两个独立的三相系统——三相同向量系统和三相反向量系统，完成了双回线的线间互感解耦，解耦后的六序分量和双回线电流电压关系用式（2）表达，可见三相同向量系统的各相之间存在互感、三相反向量系统的各相之间也存在互感，但同向量系统和反向量系统之间没有了互感。The impedance matrix of the fully transposed double-circuit line shown in Figure 1 is full and difficult to solve. The essence of the six-sequence transformation ^[2] is to decouple the inter-line mutual inductance of double-circuit lines and the phase-to-phase mutual inductance of single-circuit lines. First use the P matrix of formula (1) to transform the phasors of the fully transposed double-circuit line, the essence of which is to divide the six-phase current into two parts: three same vectors (through the amount, represented by T) and three Reverse amount (circulation flow, represented by F). Since the three same-vector currents differ by 120° from each other, the induced potentials generated in the reverse loops cancel each other out, and the induced potentials of the three self-contained loops in the same-vector loops also cancel each other out, so the same, There is no mutual inductance between the reverse vector circuits, thus decoupling the double circuit line into two independent three-phase systems - three identical vector systems and three opposite vector systems, completing the decoupling of mutual inductance between lines of double circuit lines, decoupling The relationship between the six-sequence components after coupling and the current and voltage of the double circuit is expressed by formula (2). It can be seen that there is mutual inductance between the phases of the three-identical vector system, and there is also mutual inductance between the phases of the three-opposite vector system, but the same vector system There is no mutual inductance between the system and the inverse quantity system.

$P P = = [\begin{matrix} 11 & 00 & 00 & 11 & 00 & 00 \\ 00 & 11 & 00 & 00 & 11 & 00 \\ 00 & 00 & 11 & 00 & 00 & 11 \\ 11 & 00 & 00 & - - 11 & 00 & 00 \\ 00 & 11 & 00 & 00 & - - 11 & 00 \\ 00 & 00 & 11 & 00 & 00 & - - 11 \end{matrix}] - - - - - - ((11))$

$[\begin{matrix} {\overset{\cdot &Center Dot;}{U u}}_{mnTA wxya} \\ {\overset{\cdot \cdot}{U u}}_{mnTB wxya} \\ {\overset{\cdot &Center Dot;}{U u}}_{mnTC wxya} \\ {\overset{\cdot &Center Dot;}{U u}}_{mnFA wxya} \\ {\overset{\cdot \cdot}{U u}}_{mnFB mFB} \\ {\overset{\cdot \cdot}{U u}}_{mnFC mnFC} \end{matrix}] = = [\begin{matrix} {Z Z}_{S S} + + {Z Z}_{M m}^{' '} & {Z Z}_{M m} + + {Z Z}_{M m}^{' '} & {Z Z}_{M m} + + {Z Z}_{M m}^{' '} \\ {Z Z}_{M m} + + {Z Z}_{M m}^{' '} & {Z Z}_{S S} + + {Z Z}_{M m}^{' '} & {Z Z}_{M m} + + {Z Z}_{M m}^{' '} & 00 \\ {Z Z}_{S S} - - {Z Z}_{M m}^{' '} & {Z Z}_{M m} - - {Z Z}_{M m}^{' '} & {Z Z}_{M m} - - {Z Z}_{M m}^{' '} \\ 00 & {Z Z}_{M m} - - {Z Z}_{M m}^{' '} & {Z Z}_{S S} - - {Z Z}_{M m}^{' '} & {Z Z}_{M m} - - {Z Z}_{M m}^{' '} \\ {Z Z}_{M m} - - {Z Z}_{M m}^{' '} & {Z Z}_{M m} - - {Z Z}_{M m}^{' '} & {Z Z}_{S S} - - {Z Z}_{M m}^{' '} \end{matrix}] \cdot &Center Dot; [\begin{matrix} {\overset{\cdot \cdot}{I I}}_{mnTA wxya} \\ {\overset{\cdot &Center Dot;}{I I}}_{mnTB wxya} \\ {\overset{\cdot \cdot}{I I}}_{mnTC wxya} \\ {\overset{\cdot \cdot}{I I}}_{mnFA wxya} \\ {\overset{\cdot \cdot}{I I}}_{mnFB mFB} \\ {\overset{\cdot &Center Dot;}{I I}}_{mnFC mnFC} \end{matrix}] - - - - - - ((22))$

式中，T₀、T₁和T₂分别代表同零序、同正序和同负序量；F₀、F₁和F₂分别代表反零序、反正序和反负序量。In the formula, T ₀ , T ₁ and T ₂ represent the same zero sequence, the same positive sequence and the same negative sequence respectively; F ₀ , F ₁ and F ₂ represent the anti-zero sequence, anti-sequence and anti-negative sequence respectively.

为了消除同向量系统和反向量系统中的各自三相之间的互感，再对同、反相量分别利用公式（3）的对称分量变换矩阵S进行变换，从而形成六序分量式（4）。In order to eliminate the mutual inductance between the three phases in the same vector system and the reverse quantity system, the same and reverse quantities are transformed by the symmetric component transformation matrix S of the formula (3), thus forming the six-sequence component formula (4) .

$S S = = [\begin{matrix} 11 & 11 & 11 & 00 & 00 & 00 \\ 00 & a a & {a a}^{22} & 00 & 00 & 00 \\ 00 & {a a}^{22} & a a & 00 & 00 & 00 \\ 00 & 00 & 00 & 11 & 11 & 11 \\ 00 & 00 & 00 & 11 & a a & {a a}^{22} \\ 00 & 00 & 00 & 11 & {a a}^{22} & a a \end{matrix}] - - - - - - ((33))$

其中，a＝e^j2π/3。Wherein, a=e ^j2π/3 .

$[\begin{matrix} {\overset{\cdot \cdot}{U u}}_{mnT wxya 00} \\ {\overset{\cdot &Center Dot;}{U u}}_{mnF f 00} \\ {\overset{\cdot &Center Dot;}{U u}}_{mnT wxya 11} \\ {\overset{\cdot &Center Dot;}{U u}}_{mnF f 11} \\ {\overset{\cdot &Center Dot;}{U u}}_{mnT wxya 22} \\ {\overset{\cdot &Center Dot;}{U u}}_{mnF f 22} \end{matrix}] = = [\begin{matrix} {Z Z}_{T T 00} \\ {Z Z}_{F f 00} \\ {Z Z}_{T T 11} \\ {Z Z}_{F f 11} \\ {Z Z}_{T T 22} \\ {Z Z}_{F f 22} \end{matrix}] \cdot &Center Dot; [\begin{matrix} {\overset{\cdot &Center Dot;}{I I}}_{mnT wxya 00} \\ {\overset{\cdot &Center Dot;}{I I}}_{mnF f 00} \\ {\overset{\cdot &Center Dot;}{I I}}_{mnT wxya 11} \\ {\overset{\cdot &Center Dot;}{I I}}_{mnF f 11} \\ {\overset{\cdot &Center Dot;}{I I}}_{mnT wxya 22} \\ {\overset{\cdot &Center Dot;}{I I}}_{mnF f 22} \end{matrix}] - - - - - - ((44))$

将上述两种变换过程合起来，就得到双回线解耦的最终变换矩阵M。Combining the above two transformation processes, the final transformation matrix M of double-loop decoupling is obtained.

$M m = = [\begin{matrix} 11 & 11 & 11 & 11 & 11 & 11 \\ 11 & 11 & {a a}^{22} & {a a}^{22} & a a & a a \\ 11 & 11 & a a & a a & {a a}^{22} & {a a}^{22} \\ 11 & - - 11 & 11 & - - 11 & 11 & - - 11 \\ 11 & - - 11 & {a a}^{22} & - - {a a}^{22} & a a & - - a a \\ 11 & - - 11 & a a & - - a a & {a a}^{22} & - - {a a}^{22} \end{matrix}] - - - - - - ((55))$

下面分析总结同杆双回线系统的六序分量故障特征。The following analysis summarizes the six-sequence component fault characteristics of the double-circuit line system on the same pole.

图1的同杆双回线发生单回线三相故障如IABC时，由于两回线各自三相对称，会存在正序量（1序量），且两回线间不平衡，会出现反向量（F向量）。因此，此故障时电流中存在

且故障点满足

单回线的其余故障由于每回线本身的平衡被打破，线间也不再平衡，所以故障电流中同、反向量的各序量均存在。When a single-circuit three-phase fault occurs on the double-circuit line on the same pole in Figure 1, such as IABC, there will be a positive sequence quantity (1 sequence quantity) due to the three-phase symmetry of the two circuit lines, and there will be an imbalance between the two circuit lines, and there will be a negative sequence. vector(F-vector). Therefore, during this fault current exists in the

And the point of failure satisfies

For the remaining faults of the single circuit line, the balance of each circuit line itself is broken, and the balance between lines is no longer, so all sequence quantities of the same and opposite quantities in the fault current exist.

当发生同名相跨线故障如IAIIAG或IBCIIBCG时，双回线间依然平衡，所以故障电流中只存在同向量即

和

非同名的两相、三相、四相和五相跨线故障，同、反向量的各序量均存在。When a phase cross-line fault with the same name occurs, such as IAIIAG or IBCIIBCG, the double-circuit line is still balanced, so there is only the same vector in the fault current, that is,

and

For two-phase, three-phase, four-phase and five-phase cross-line faults with different names, all sequence quantities of the same and opposite quantities exist.

当发生六相故障时，单回线内部平衡，双回线间也平衡，所以故障电流中仅存在

由以上分析可知，能够反应双回线的所有故障，

主要反应同名相跨线故障，

主要反应单回线三相故障。因此，只要三者进行合适的复合，就可以灵敏反应所有类型的故障。为了消除负荷电流的影响，采用

的故障分量

将所构成的复合电流作为相差保护的操作电流，即比较双回线M、N两端的操作电流的相位动作。因此，同杆双回线的纵联相差保护动作判据表示为When a six-phase fault occurs, the single-circuit line is balanced internally, and the double-circuit line is also balanced, so only the fault current exists

From the above analysis, we can see that, Can respond to all faults of the double circuit line,

It mainly reflects the phase crossing fault of the same name,

It mainly responds to single-circuit three-phase faults. Therefore, as long as the three are combined properly, all types of faults can be sensitively responded. In order to eliminate the effect of load current, adopt

fault component of

Will The composite current formed is used as the operating current of the phase difference protection, namely Compare the phase action of the operating current at both ends of the double circuit lines M and N. Therefore, the action criterion of the longitudinal phase difference protection for double circuit lines on the same pole is expressed as

其中

为相差保护的动作角，按照常规整定原则取

l为被保护线路长度，km。in

is the action angle of the phase difference protection, which is selected according to the conventional setting principle

l is the length of the protected line, km.

为防止发生故障时

和

相互抵消,保证操作电流的可靠性，采用下式作为选择K值的原则。To prevent failure

and

To offset each other to ensure the reliability of the operating current, the following formula is used as the principle for selecting the K value.

$| | {K K}_{F f 11} {\overset{\cdot &Center Dot;}{I I}}_{F f 11} + + {K K}_{T T 22} {\overset{\cdot &Center Dot;}{I I}}_{T T 22} | | &GreaterEqual; &Greater Equal; 1.5 1.5 | | Δ Δ {\overset{\cdot &Center Dot;}{I I}}_{T T 11} | | - - - - - - ((77))$

即 $| K_{F 1} {\overset{\cdot}{I}}_{F 1} + K_{T 2} {\overset{\cdot}{I}}_{T 2} | - 1.5 | Δ {\overset{\cdot}{I}}_{T 1} | &GreaterEqual; 0$ Right now $| K_{f 1} {\overset{\cdot}{I}}_{f 1} + K_{T 2} {\overset{&Center Dot;}{I}}_{T 2} | - 1.5 | Δ {\overset{\cdot}{I}}_{T 1} | &Greater Equal; 0$

双回线完全换位情况下，

忽略阻抗中的电阻，实际系统中Z_F0/Z_T0≈6。由此得到各种故障时的动作判据表达式列于表1-1中。In the case of complete transposition of double circuit lines,

Neglecting the resistance in the impedance, Z _F0 /Z _T0 ≈6 in the actual system. The action criterion expressions for various faults are thus listed in Table 1-1.

表1-1双回线各种故障类型K值选择Table 1-1 Selection of K value for various fault types of double circuit lines

Tab 1-1 The selection of K value over a variety of double transmission lines fault patternsTab 1-1 The selection of K value over a variety of double transmission lines fault patterns

为了使表中所列判据满足式（7），建议K_T2取19～21，K_F1取2～4。这种取值在理论上可以保证各种故障时都能使输出的复合电流不为零，正确反应各种故障，并可靠动作。In order to make the criteria listed in the table satisfy formula (7), it is recommended that K _T2 be 19-21, and K _F1 be 2-4. This value can theoretically ensure that the output composite current is not zero in case of various faults, correctly respond to various faults, and operate reliably.

本发明的保护方法可概括如下：Protection method of the present invention can be summarized as follows:

1、保护装置通过输电线路m侧及n侧的CT采集线路两侧的电流，利用序分量变换公式和全波傅立叶算法计算出两侧电流的六个序分量；1. The protection device collects the current on both sides of the line through the CT on the m side and the n side of the transmission line, and uses the sequence component transformation formula and the full-wave Fourier algorithm to calculate the six sequence components of the current on both sides;

2、用

减去正常运行的负荷电流得到故障分量 2, use

Subtract the normal operating load current to get the fault component

3、将构成的复合电流作为相差保护的操作电流代入判定方程（6），若等式成立则判定为内部故障，否则判为外部故障。3. will The composed composite current is substituted into the judgment equation (6) as the operating current of the phase difference protection. If the equation holds true, it is judged as an internal fault, otherwise it is judged as an external fault.

Claims

1. A phase difference protection method for double circuit lines on the same pole based on six-sequence components, comprising the following steps:

(1) Collect six currents on each side of the double-circuit line through the current transformers at the protective installations on both sides of the line m and n;

(2) Transform the six currents on each side of the double-circuit line into six sequence current components through six-sequence transformation:

and are the same zero-sequence component, same positive sequence component, same negative sequence component, anti-zero sequence component, anti-sequence component and anti-negative sequence component of side m, respectively; and

are the same zero-sequence components, same positive sequence components, same negative sequence components, anti-zero-sequence components, anti-sequence components and anti-negative-sequence components of side n, respectively;

(3) Same positive sequence component for m

and the same positive sequence components on both sides of n Subtract the sequence component corresponding to the week before the fault respectively to obtain the same positive sequence fault component

(4) use and

Recombination currents on the side m

and the recombination current on the n-side

Obtain the phase angle of the composite current on both sides respectively;

(5) Let the action angle of the phase difference protection be

If the absolute value of the phase angle difference of the composite current on both sides of the line is less than

If it is judged as an internal fault, otherwise it is judged as an external fault.

2. The phase difference protection method for double circuit lines on the same pole based on six-sequence components according to claim 1, characterized in that,

l is the length of the protected line, unit: km.

3 . The phase difference protection method for double circuit lines on the same pole based on six-sequence components according to claim 1 , wherein K _F1 is 2-4, and K _T2 is 19-21. 4 .