CN103683229B - Method for protecting power grid wide-area relay based on unit output power and load change influence - Google Patents

Abstract

The invention discloses a method for protecting a power grid wide-area relay based on unit output power and load change influence. Firstly, a power grid existing wide area measurement system is used for synchronously measuring the voltages and currents of all transformer substations of a power grid to acquire power grid synchronous data. The incidence matrix between the currents of all circuits of the power grid is calculated through a wide area backup protection system, and the incidence matrix between the currents of all the circuits of the power grid and node injection currents is calculated. When a power grid topological structure is changed after a power grid dual-circuit fault and tripping occur, the admittance matrix of power grid branch circuits and the incidence matrix of power grid nodes do not need to be calculated again, the variation of the transient currents of other circuits of the power grid are calculated directly through power grid parameters before a dual-circuit fault, calculation time is short, and the protection movement speed is high and is higher than that of an existing circuit backup protection algorithm based on local quantity decisions.

Description

Consider unit output and the electrical network wide area relay protection method of load variations impact

Technical field

The present invention relates to Relay Protection Technology in Power System field, concretely relate to a kind of consideration unit output and bear The electrical network wide area relay protection method of lotus change impact.

Background technology

The task of relay protection is fault and the irregular operating state of reflection protected element, can be divided into master according to function Protection and back-up protection.Wherein main protection is only responsible for the task of quickly excising protected element fault, is not transported by system The impact of line mode.Along with the application of optical-fibre channel, high pressure based on Two-Terminal Electrical Quantities, extra high voltage system main protection technology day Attain maturation.And back-up protection is also responsible for the task of doing the remote back-up protection of adjacent electrical element, owing to there is transforming plant DC The possibility of power-fail, this responsibility is to cancel.The information of protection installation place is only reacted in existing electrical network back-up protection, by electricity Net topology annexation and the impact of the method for operation.For ensureing its reliability, it has to configure according to the harshest situation With adjust；For ensureing its selectivity, it has to sacrifice rapidity and the susceptiveness of back-up protection.Simultaneously because electric network composition is increasingly Complexity, results in following potential safety hazard:

1) back-up protection matching relationship is complicated, and movement time is long.Stability of power system institute likely it is unsatisfactory for time serious The critical clearing time required, and then become bulk power grid potential safety hazard.

2) back-up protection configuration is big with the difficulty adjusted, and can not follow the tracks of the change of power system operation mode, even may be used Protection mismatch or under-sensitive situation can occur.

3) power flow transfer that back-up protection causes after cannot distinguish between internal fault and failure removal, this is likely to result in heavy burden Back-up protection cascading trip in the case of lotus.

In large-scale blackout, although having occurred as soon as power system back-up protection according to design principle correct operation, but The most but the phenomenon of system crash is accelerated.Accordingly, it is considered to the backup protection system for damping research of electrical network global information is extremely urgent.

In recent years, wide area measurement systems (WAMS) appear as in back-up protection, introduce system information provide can Energy.WAMS mono-is can to synchronize to obtain the electrical phasor in the whole network, it is achieved that the monitoring of dynamic process of electrical power system；Two is to measure The renewal speed measured was tapered to a few tens of milliseconds by several seconds, controlled to create condition for realizing dynamic process of electrical power system so that It is designed to possibility from what the angle of electrical network total optimization carried out back-up protection.

Summary of the invention

It is an object of the invention to the deficiency overcoming prior art to exist, it is provided that a kind of consideration unit output and load variations The electrical network wide area relay protection method of impact.The inventive method topological structure of electric after electrical network dual circuit fault trip occurs During change, it is not necessary to recalculate grid branch admittance matrix, grid nodes incidence matrix, directly utilize electricity before dual circuit fault Network parameters calculates the transient current variable quantity of electrical network All other routes, calculates the time short, and protection act speed is fast, be faster than existing based on The line backup protection algorithm of local amount decision-making.Before and after the inventive method considers dual circuit fault trip in algorithm model Unit output and the load variations impact on electrical network All other routes transient current variable quantity, can in circuit overload back-up protection by mistake By reliable for circuit locking before action, other faulty line fast trips can be isolated, strengthen safe operation of electric network stability.

It is an object of the invention to be achieved through the following technical solutions:

Consider unit output and the electrical network wide area relay protection method of load variations impact, it is characterised in that include as follows Sequential steps:

(1) wide area backup protection system utilize the electrical network existing WAMS each transformer substation voltage of synchro measure electrical network, Electric current, obtains synchronized data in real time；Incidence matrix ζ between wide area backup protection system-computed electrical network each bar line current =YA^T(AYA^T)^-1A；Wherein, Y is grid branch admittance matrix；A is grid nodes incidence matrix；A^TSquare is associated for grid nodes The transposed matrix of battle array A；

(2) the incidence matrix λ between wide area backup protection system-computed electrical network each bar line current and node injection current =YA^T(AYA^T)^-1；Wherein, Y is grid branch admittance matrix；A is grid nodes incidence matrix；A^TFor grid nodes incidence matrix The transposed matrix of A；

(3) if after circuit i and the chopper tripping of circuit j two ends, wide area backup protection system-computed unit is exerted oneself and load The change contribution amount to circuit k transient current variable quantity

$\mathrm{\Δ}{\stackrel{\·}{I}}_k^{\′}=({\mathrm{\λ}}_k+\frac{{\mathrm{\ζ}}_{\mathrm{ki}}+{\mathrm{\ζ}}_{\mathrm{kj}}{\mathrm{\ζ}}_{\mathrm{ji}}}{1-{\mathrm{\ζ}}_{\mathrm{ij}}{\mathrm{\ζ}}_{\mathrm{ji}}}{\mathrm{\λ}}_i+\frac{{\mathrm{\ζ}}_{\mathrm{kj}}+{\mathrm{\ζ}}_{\mathrm{ki}}{\mathrm{\ζ}}_{\mathrm{ij}}}{1-{\mathrm{\ζ}}_{\mathrm{ji}}{\mathrm{\ζ}}_{\mathrm{ij}}}{\mathrm{\λ}}_j)({\stackrel{\·}{I}}^{\′}-\stackrel{\·}{I})$

Wherein, i is circuit number；J is circuit number；K is circuit number；Circuit k, circuit i and circuit j different circuits each other； N is electricity grid substation sum；ζ_kiRow k the i-th column element for incidence matrix ζ；ζ_kjRow k jth column element for incidence matrix ζ； ζ_jiJth row the i-th column element for incidence matrix ζ；ζ_ijThe i-th row jth column element for incidence matrix ζ；I=1,2,3 ..., n-2, n- 1、n；J=1,2,3 ..., n-2, n-1, n；K=1,2,3 ..., n-2, n-1, n； $\stackrel{\·}{I}={\left[\begin{array}{ccccccc}{\stackrel{\·}{I}}_1& {\stackrel{\·}{I}}_2& {\stackrel{\·}{I}}_3& ...& {\stackrel{\·}{I}}_{n-2}& {\stackrel{\·}{I}}_{n-1}& {\stackrel{\·}{I}}_n\end{array}\right]}^T$ Matrix is tieed up for n × 1,Before being respectively circuit i and the chopper tripping of circuit j two ends, numbered 1st, 2,3 ..., the injection current of n-2, n-1, n transformer station；λ_kRow k for incidence matrix λ； ${\stackrel{\·}{I}}^{\′}={\left[\begin{array}{ccccccc}{\stackrel{\·}{I}}_1^{\′}& {\stackrel{\·}{I}}_2^{\′}& {\stackrel{\·}{I}}_3^{\′}& ...& {\stackrel{\·}{I}}_{n-2}^{\′}& {\stackrel{\·}{I}}_{n-1}^{\′}& {\stackrel{\·}{I}}_n^{\′}\end{array}\right]}^T$ Matrix is tieed up for n × 1,It is respectively circuit i After the chopper tripping of circuit j two ends, numbered 1st, 2,3 ..., the injection current of n-2, n-1, n transformer station；λ_iFor association square I-th row of battle array λ；λ_jJth row for incidence matrix λ；

(4) circuit i and the electric current of circuit j before wide area backup protection system-computed circuit i and the chopper tripping of circuit j two ends Contribution amount to circuit k transient current variable quantity

$\mathrm{\Δ}{\stackrel{\·}{I}}_k^{\′\′}=\frac{{\mathrm{\ζ}}_{\mathrm{ki}}+{\mathrm{\ζ}}_{\mathrm{kj}}{\mathrm{\ζ}}_{\mathrm{ji}}}{1-{\mathrm{\ζ}}_{\mathrm{ij}}{\mathrm{\ζ}}_{\mathrm{ji}}}{\stackrel{\·}{I}}_i+\frac{{\mathrm{\ζ}}_{\mathrm{kj}}+{\mathrm{\ζ}}_{\mathrm{ki}}{\mathrm{\ζ}}_{\mathrm{ij}}}{1-{\mathrm{\ζ}}_{\mathrm{ji}}{\mathrm{\ζ}}_{\mathrm{ij}}}{\stackrel{\·}{I}}_j$

Wherein,Before circuit i and the chopper tripping of circuit j two ends, WAMS measures the electric current of circuit i；Before circuit i and the chopper tripping of circuit j two ends, WAMS measures the electric current of circuit j；

(5) ifSet up, then wide area backup protection system judges that circuit k is normal, to circuit k two ends Chopper sends block signal；IfSet up, then wide area backup protection system judges that circuit k occurs event Barrier, sends action trip signal, tripping circuit k two ends chopper；Wherein,For circuit i and the chopper tripping of circuit j two ends After, WAMS measures the transient current variable quantity on circuit k.

The present invention compared with prior art, has a following positive achievement:

The inventive method is first with the voltage of each transformer station of electrical network existing WAMS synchro measure electrical network, electricity Stream, obtains synchronized data；Incidence matrix between wide area backup protection system-computed electrical network each bar line current, calculates electricity Net the incidence matrix between each bar line current and node injection current；If electrical network generation dual circuit fault trip, after wide area Standby protection system-computed unit is exerted oneself and the load variations contribution amount to electrical network All other routes transient current variable quantity, calculates dual Before line fault tripping operation, the contribution amount of the Current on Grid All other routes transient current variable quantity on dual circuit, calculates doublet Electrical network All other routes transient current variable quantity after the fault trip of road, then utilizes and is calculated circuit transient current variable quantity with wide Domain measurement systematic survey constitutes relay protection criterion to circuit transient current variable quantity.The inventive method is in the event of electrical network dual circuit When after barrier tripping operation, topological structure of electric changes, it is not necessary to recalculate grid branch admittance matrix, grid nodes incidence matrix, Before directly utilizing dual circuit fault, electrical network parameter calculates the transient current variable quantity of electrical network All other routes, calculates the time short, protects Protect quick action, be faster than existing line backup protection algorithm based on this locality amount decision-making.The inventive method is in algorithm model Consider unit output and the load variations shadow to electrical network All other routes transient current variable quantity before and after dual circuit fault trip Ring, can by reliable for circuit locking before circuit overload back-up protection misoperation, can by other faulty line fast trips every From, strengthen safe operation of electric network stability.

Accompanying drawing explanation

Fig. 1 is consideration unit output and the electrical network wide area relay protection method flow process of load variations impact of the application present invention Figure.

Detailed description of the invention

Below according to Figure of description, technical scheme is expressed in further detail.

Fig. 1 is consideration unit output and the electrical network wide area relay protection method flow process of load variations impact of the application present invention Figure.In the present embodiment, wide area backup protection system utilizes each transformer station of electrical network existing WAMS synchro measure electrical network Voltage, electric current phasor, obtain synchronized data.

Incidence matrix ζ=YA between wide area backup protection system-computed electrical network each bar line current^T(AYA^T)^-1A；Its In, Y is grid branch admittance matrix；A is grid nodes incidence matrix；A^TTransposed matrix for grid nodes incidence matrix A.

Incidence matrix λ between wide area backup protection system-computed electrical network each bar line current and node injection current= YA^T(AYA^T)^-1。

If after circuit i and the chopper tripping of circuit j two ends, wide area backup protection system-computed unit is exerted oneself and load variations Contribution amount to circuit k transient current variable quantity

$\mathrm{\Δ}{\stackrel{\·}{I}}_k^{\′}=({\mathrm{\λ}}_k+\frac{{\mathrm{\ζ}}_{\mathrm{ki}}+{\mathrm{\ζ}}_{\mathrm{kj}}{\mathrm{\ζ}}_{\mathrm{ji}}}{1-{\mathrm{\ζ}}_{\mathrm{ij}}{\mathrm{\ζ}}_{\mathrm{ji}}}{\mathrm{\λ}}_i+\frac{{\mathrm{\ζ}}_{\mathrm{kj}}+{\mathrm{\ζ}}_{\mathrm{ki}}{\mathrm{\ζ}}_{\mathrm{ij}}}{1-{\mathrm{\ζ}}_{\mathrm{ji}}{\mathrm{\ζ}}_{\mathrm{ij}}}{\mathrm{\λ}}_j)({\stackrel{\·}{I}}^{\′}-\stackrel{\·}{I})$

Wherein, i is circuit number；J is circuit number；K is circuit number；Circuit k, circuit i and circuit j different circuits each other； N is electricity grid substation sum；ζ_kiRow k the i-th column element for incidence matrix ζ；ζ_kjRow k jth column element for incidence matrix ζ； ζ_jiJth row the i-th column element for incidence matrix ζ；ζ_ijThe i-th row jth column element for incidence matrix ζ；I=1,2,3 ..., n-2, n- 1、n；J=1,2,3 ..., n-2, n-1, n；K=1,2,3 ..., n-2, n-1, n； $\stackrel{\·}{I}={\left[\begin{array}{ccccccc}{\stackrel{\·}{I}}_1& {\stackrel{\·}{I}}_2& {\stackrel{\·}{I}}_3& ...& {\stackrel{\·}{I}}_{n-2}& {\stackrel{\·}{I}}_{n-1}& {\stackrel{\·}{I}}_n\end{array}\right]}^T$ Matrix is tieed up for n × 1,Before being respectively circuit i and the chopper tripping of circuit j two ends, numbered 1st, 2,3 ..., the injection current of n-2, n-1, n transformer station；λ_kRow k for incidence matrix λ； ${\stackrel{\·}{I}}^{\′}={\left[\begin{array}{ccccccc}{\stackrel{\·}{I}}_1^{\′}& {\stackrel{\·}{I}}_2^{\′}& {\stackrel{\·}{I}}_3^{\′}& ...& {\stackrel{\·}{I}}_{n-2}^{\′}& {\stackrel{\·}{I}}_{n-1}^{\′}& {\stackrel{\·}{I}}_n^{\′}\end{array}\right]}^T$ Matrix is tieed up for n × 1,It is respectively circuit i After the chopper tripping of circuit j two ends, numbered 1st, 2,3 ..., the injection current of n-2, n-1, n transformer station；λ_iFor association square I-th row of battle array λ；λ_jJth row for incidence matrix λ.

Circuit i and the electric current pair of circuit j before wide area backup protection system-computed circuit i and the chopper tripping of circuit j two ends The contribution amount of circuit k transient current variable quantity

$\mathrm{\Δ}{\stackrel{\·}{I}}_k^{\′\′}=\frac{{\mathrm{\ζ}}_{\mathrm{ki}}+{\mathrm{\ζ}}_{\mathrm{kj}}{\mathrm{\ζ}}_{\mathrm{ji}}}{1-{\mathrm{\ζ}}_{\mathrm{ij}}{\mathrm{\ζ}}_{\mathrm{ji}}}{\stackrel{\·}{I}}_i+\frac{{\mathrm{\ζ}}_{\mathrm{kj}}+{\mathrm{\ζ}}_{\mathrm{ki}}{\mathrm{\ζ}}_{\mathrm{ij}}}{1-{\mathrm{\ζ}}_{\mathrm{ji}}{\mathrm{\ζ}}_{\mathrm{ij}}}{\stackrel{\·}{I}}_j$

Wherein,Before circuit i and the chopper tripping of circuit j two ends, WAMS measures the electric current of circuit i；Before circuit i and the chopper tripping of circuit j two ends, WAMS measures the electric current of circuit j.

IfSet up, then wide area backup protection system judges that circuit k is normal, disconnected to circuit k two ends Road device sends block signal.

IfSet up, then wide area backup protection system judges that circuit k breaks down, and sends action and jumps Lock signal, tripping circuit k two ends chopper；Wherein,After circuit i and the chopper tripping of circuit j two ends, wide area measurement system Unified test amount is to the transient current variable quantity on circuit k.

The inventive method is time after electrical network dual circuit fault trip, topological structure of electric changes, it is not necessary to recalculate Grid branch admittance matrix, grid nodes incidence matrix, directly utilize electrical network parameter before dual circuit fault calculate electrical network other The transient current variable quantity of circuit, calculates the time short, and protection act speed is fast, after being faster than existing circuit based on this locality amount decision-making Standby protection algorism.The inventive method considers unit output and load variations before and after dual circuit fault trip in algorithm model Impact on electrical network All other routes transient current variable quantity, can be reliable by circuit before circuit overload back-up protection misoperation Locking, can isolate other faulty line fast trips, strengthens safe operation of electric network stability.

The foregoing is only the preferred embodiment of the present invention, but protection scope of the present invention is not limited thereto, appoint How those familiar with the art is in the technical scope that the invention discloses, the change that can readily occur in or replacement, all Should contain within protection scope of the present invention.

Claims (1)

1. consider unit output and the electrical network wide area relay protection method of load variations impact, it is characterised in that: include depending on as follows Sequence step:

(1) wide area backup protection system utilizes the electrical network existing WAMS each transformer substation voltage of synchro measure electrical network, electric current, Obtain synchronized data in real time；Incidence matrix ζ=YA between wide area backup protection system-computed electrical network each bar line current^T (AYA^T)^-1A；Wherein, Y is grid branch admittance matrix；A is grid nodes incidence matrix；A^TFor grid nodes incidence matrix A's Transposed matrix；

(2) the incidence matrix λ=YA between wide area backup protection system-computed electrical network each bar line current and node injection current^T (AYA^T)^-1；Wherein, Y is grid branch admittance matrix；A is grid nodes incidence matrix；A^TFor grid nodes incidence matrix A's Transposed matrix；

(3) if after circuit i and the chopper tripping of circuit j two ends, wide area backup protection system-computed unit is exerted oneself and load variations Contribution amount to circuit k transient current variable quantity

$\mathrm{\Δ}{\stackrel{\·}{I}}_k^{\′}=\left({\mathrm{\λ}}_k+\frac{{\mathrm{\ζ}}_{ki}+{\mathrm{\ζ}}_{kj}{\mathrm{\ζ}}_{ji}}{1-{\mathrm{\ζ}}_{ij}{\mathrm{\ζ}}_{ji}}{\mathrm{\λ}}_i+\frac{{\mathrm{\ζ}}_{kj}+{\mathrm{\ζ}}_{ki}{\mathrm{\ζ}}_{ij}}{1-{\mathrm{\ζ}}_{ji}{\mathrm{\ζ}}_{ij}}{\mathrm{\λ}}_j\right)\left({\stackrel{\·}{I}}^{\′}-\stackrel{\·}{I}\right)$

Wherein, i is circuit number；J is circuit number；K is circuit number；Circuit k, circuit i and circuit j different circuits each other；n For electricity grid substation sum；ζ_kiRow k the i-th column element for incidence matrix ζ；ζ_kjRow k jth column element for incidence matrix ζ； ζ_jiJth row the i-th column element for incidence matrix ζ；ζ_ijThe i-th row jth column element for incidence matrix ζ；I=1,2,3 ..., n-2, n-1, n；J=1,2,3 ..., n-2, n-1, n；K=1,2,3 ..., n-2, n-1, n； Matrix is tieed up for n × 1,Before being respectively circuit i and the chopper tripping of circuit j two ends, numbered 1st, 2,3 ..., the injection current of n-2, n-1, n transformer station；λ_kRow k for incidence matrix λ；Matrix is tieed up for n × 1,It is respectively circuit i After the chopper tripping of circuit j two ends, numbered 1st, 2,3 ..., the injection current of transformer station of n-2, n-1, n；λ_iFor closing I-th row of connection matrix λ；λ_jJth row for incidence matrix λ；

(4) before wide area backup protection system-computed circuit i and the chopper tripping of circuit j two ends the electric current of circuit i and circuit j to line The contribution amount of road k transient current variable quantity

$\mathrm{\Δ}{\stackrel{\·}{I}}_k^{\′\′}=\frac{{\mathrm{\ζ}}_{ki}+{\mathrm{\ζ}}_{kj}{\mathrm{\ζ}}_{ji}}{1-{\mathrm{\ζ}}_{ij}{\mathrm{\ζ}}_{ji}}{\stackrel{\·}{I}}_i+\frac{{\mathrm{\ζ}}_{kj}+{\mathrm{\ζ}}_{ki}{\mathrm{\ζ}}_{ij}}{1-{\mathrm{\ζ}}_{ji}{\mathrm{\ζ}}_{ij}}{\stackrel{\·}{I}}_j$

Wherein,Before circuit i and the chopper tripping of circuit j two ends, WAMS measures the electric current of circuit i；For line Before road i and the chopper tripping of circuit j two ends, WAMS measures the electric current of circuit j；

(5) ifSet up, then wide area backup protection system judges that circuit k is normal, to circuit k two ends open circuit Device sends block signal；IfSet up, then wide area backup protection system judges that circuit k breaks down, and sends out Go out action trip signal, tripping circuit k two ends chopper；Wherein,After circuit i and the chopper tripping of circuit j two ends, extensively Domain measurement systematic survey is to the transient current variable quantity on circuit k.