CN103779846A - Power grid line wide-area current protection method based on admittance matrix fast correction - Google Patents

Abstract

The invention discloses a power grid line wide-area current protection method based on admittance matrix fast correction. Synchronous measurement of voltage and current phasors of each transformer substation of a power grid is achieved through an existing power-grid wide-area measurement system of the power grid, and power-grid synchronous data are acquired; if a single circuit of the power grid is opened, a middle matrix, a variable matrix, the voltage variation matrix of each transformer substation of the power grid and the variation of the current passing through each circuit of the power grid will be calculated by a wide-area back-up protection system, and wide-area current protection criteria are constituted by the variation of the current passing through each circuit of the power grid and the variation, measured by the wide-area measurement system, of the current passing through each circuit of the power grid. The whole calculation process is finished within 200 ms, the circuits can be reliably locked before circuit overload protection false operation, the phenomenon that after a single circuit of the power grid is opened, overload of other circuits is generated and the other circuits are cut off by mistake due to flow transferring is effectively avoided, fault circuits can be quickly opened before back-up circuit protection motion so as to be isolated from the power grid, and operation safety and stability of the power grid are improved.

Description

The power network line wide area current protection method of revising fast based on admittance matrix

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to a kind of power network line wide area current protection method of revising fast based on admittance matrix.

Background technology

The task of relaying protection is fault and the irregular operating state of reflection protected element, can be divided into main protection and backup protection according to function.Wherein the task of excision protected element fault fast is only being undertaken in main protection, is not substantially subject to the impact of system operation mode.Along with the application of optical-fibre channel, high pressure, extra high voltage system main protection technology based on Two-Terminal Electrical Quantities are ripe day by day.And the task of doing the backup protection far away of adjacent electric component is also being undertaken in backup protection, owing to existing the possibility of transforming plant DC power-fail, this responsibility is to cancel.The information of protection installation place is only reacted in existing electrical network backup protection, is subject to the impact of power network topology annexation and operational mode.For guaranteeing its reliability, have to be configured and adjust according to the harshest situation; For guaranteeing its selectivity, have to sacrifice rapidity and the sensitivity of backup protection.Because electric network composition is increasingly sophisticated, just cause following potential safety hazard simultaneously:

1) backup protection matching relationship complexity, operate time is long.When serious, likely do not meet the desired critical clearing time of stability of power system, and then become large power grid security hidden danger.

2) backup protection configuration is large with the difficulty of adjusting, and can not follow the tracks of the variation of power system operation mode, even may occur protecting mismatch or under-sensitive situation.

3) backup protection can not be distinguished the trend transfer causing after internal fault and failure removal, and this likely causes the backup protection cascading trip in heavy load situation.

In the accident of having a power failure on a large scale, although just occurred that electric power system backup protection, according to design principle correct operation, objectively but accelerated the phenomenon of system crash.Therefore the backup protection system for damping of, considering electrical network global information is studied extremely urgent.

In recent years, the drawing-in system information in backup protection that appears as of wide area synchronized measurement system (WAMS) provides possibility.WAMS mono-is the electric phasor that can synchronously obtain in the whole network, has realized the monitoring of dynamic process of electrical power system; The 2nd, the renewal speed of measurement amount was tapered to a few tens of milliseconds by several seconds, create condition for realizing dynamic process of electrical power system control, make the design of carrying out backup protection from the angle of electrical network total optimization become possibility.

Summary of the invention

The object of the invention is to overcome the deficiency that prior art exists, a kind of power network line wide area current protection method of revising fast based on admittance matrix is provided.The method can be by reliable circuit locking before circuit overload is protected misoperation; after effectively preventing the tripping operation of electrical network uniline, trend transfer causes that All other routes overload is excised by mistake; can be by faulty line fast trip before line backup protection action; in time faulty line and electrical network are kept apart, improve the security and stability of operation of power networks.

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

The power network line wide area current protection method of revising fast based on admittance matrix, is characterized in that, comprises following sequential steps:

(1) wide area backup protection system utilizes the existing WAMS of electrical network to realize the synchro measure of the each transformer substation voltage of electrical network, electric current phasor, and Real-time Obtaining synchronized data, if after the circuit breaker tripping at circuit ij two ends, enter step (2); Wherein, circuit ij connects i transformer station and j transformer station; I=1 ..., n; J=1 ..., n; N is electricity grid substation total number;

(2) wide area backup protection system-computed intermediary matrix W=Y-1M; Wherein, Y is grid nodes admittance matrix, for n × n ties up matrix; M=[0...1...-1...0] ^tfor n × 1 dimension matrix, in Metzler matrix, capable the 1st column element of i is 1, and in Metzler matrix, capable the 1st column element of j is-1, and other elements are 0; I=1 ..., n; J=1 ..., n; N is electricity grid substation total number;

(3) wide area backup protection system-computed matrix of variables wherein, E is unit matrix, is 1 × 1 dimension matrix;

be 1 × n dimension matrix, in J matrix, the 1st row i column element is-y _ij, in J matrix, the 1st row j column element is y _ij, other elements are 0;

before circuit breaker tripping for circuit ij two ends, the each transformer substation voltage phase of the electrical network moment matrix that WAMS measures, is n × 1 dimension matrix; y _ijfor the line admittance of circuit ij;

(4) after the circuit breaker tripping at wide area backup protection system-computed circuit ij two ends, the each transformer substation voltage variable quantity of electrical network matrix $\mathrm{\Δ}\stackrel{\·}{U}=-\mathrm{WZ};$ Wherein, $\mathrm{\Δ}\stackrel{\·}{U}={\left[\begin{array}{ccccccc}\mathrm{\Δ}{\stackrel{\·}{U}}_1& \mathrm{\Δ}{\stackrel{\·}{U}}_2& \mathrm{\Δ}{\stackrel{\·}{U}}_3& \·\·\·& \mathrm{\Δ}{\stackrel{\·}{U}}_{n-2}& \mathrm{\Δ}{\stackrel{\·}{U}}_{n-1}& \mathrm{\Δ}{\stackrel{\·}{U}}_n\end{array}\right]}^T$ For n × 1 dimension matrix, $\mathrm{\Δ}{\stackrel{\·}{U}}_1,\mathrm{\Δ}{\stackrel{\·}{U}}_3,\·\·\·,\mathrm{\Δ}{\stackrel{\·}{U}}_{n-2},{\mathrm{\Δ}\stackrel{\·}{U}}_{n-1},\mathrm{\Δ}{\stackrel{\·}{U}}_n$ Be respectively after the circuit breaker tripping at circuit ij two ends, be numbered the the 1st, 2,3 ..., the voltage variety of n-2, n-1, n transformer station;

(5) current change quantity of circuit lk after the circuit breaker tripping at wide area backup protection system-computed circuit ij two ends

and judgement

whether set up, if set up, wide area backup protection system judges that circuit lk is faulty line, sends trip signal to the circuit breaker at circuit lk two ends; Wherein, l=1 ..., n; K=1 ..., n; N is electricity grid substation total number; z _lkfor the line impedance of circuit lk; I _setfor setting current threshold value;

before circuit breaker tripping for circuit ij two ends, WAMS measures the electric current flowing through on circuit lk; H=[0...1...-1...0] ^tfor n × 1 dimension matrix, in H matrix, capable the 1st column element of l is 1, and in H matrix, capable the 1st column element of k is-1, and other elements are all 0; after circuit breaker tripping for circuit ij two ends, WAMS measures the electric current flowing through on circuit lk; Circuit lk connects l transformer station and k transformer station; Circuit lk is different circuits from circuit ij.

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

The inventive method utilizes the existing WAMS of electrical network to realize the synchro measure of the each transformer substation voltage of electrical network, electric current phasor, obtains synchronized data; If there is the tripping operation of electrical network uniline; wide area backup protection system-computed intermediary matrix; calculate matrix of variables; calculate the each transformer substation voltage variable quantity of electrical network matrix; calculate the current change quantity that each line flows of electrical network crossed, utilize current change quantity and the WAMS that each the line flows of electrical network calculating crossed to measure each line current variable quantity formation power network line wide area current protection criterion of electrical network.The inventive method is in the time that the rear topological structure of electric of electrical network uniline tripping operation changes, directly calculate rear each the current change quantity that line flows is crossed of electrical network uniline tripping operation, whole computational process can complete within the 200ms time, protection quick action, faster than the existing line backup protection algorithm based on this locality amount decision-making, can be by reliable circuit locking before circuit overload is protected misoperation, after effectively preventing the tripping operation of electrical network uniline, trend transfer causes that All other routes overload is excised by mistake, can be by faulty line fast trip before line backup protection action, in time faulty line and electrical network are kept apart, improve the security and stability of operation of power networks.

Accompanying drawing explanation

Fig. 1 is application circuit transmission system schematic diagram of the present invention.

Embodiment

According to Figure of description, technical scheme of the present invention is expressed in further detail below.

Wide area backup protection system utilizes the existing WAMS of electrical network to realize the synchro measure of the each transformer substation voltage of electrical network, electric current phasor, Real-time Obtaining synchronized data.

If after the circuit breaker tripping at circuit ij two ends, wide area backup protection system-computed intermediary matrix W=Y ^-1m; Wherein, Y is grid nodes admittance matrix, for n × n ties up matrix; M=[0...1...-1...0] ^tfor n × 1 dimension matrix, in Metzler matrix, capable the 1st column element of i is 1, and in Metzler matrix, capable the 1st column element of j is-1, and other elements are 0; I=1 ..., n; J=1 ..., n; N is electricity grid substation total number; Circuit ij connects i transformer station and j transformer station.

Wide area backup protection system-computed matrix of variables

wherein, E is unit matrix, is 1 × 1 dimension matrix;

be 1 × n dimension matrix, in J matrix, the 1st row i column element is-y _ij, in J matrix, the 1st row j column element is yij, other elements are 0;

before circuit breaker tripping for circuit ij two ends, the each transformer substation voltage phase of the electrical network moment matrix that WAMS measures, is n × 1 dimension matrix; y _ijfor the line admittance of circuit ij.

After the circuit breaker tripping at wide area backup protection system-computed circuit ij two ends, the each transformer substation voltage variable quantity of electrical network matrix $\mathrm{\Δ}\stackrel{\·}{U}=-\mathrm{WZ};$ Wherein, $\mathrm{\Δ}\stackrel{\·}{U}={\left[\begin{array}{ccccccc}\mathrm{\Δ}{\stackrel{\·}{U}}_1& \mathrm{\Δ}{\stackrel{\·}{U}}_2& \mathrm{\Δ}{\stackrel{\·}{U}}_3& \·\·\·& \mathrm{\Δ}{\stackrel{\·}{U}}_{n-2}& \mathrm{\Δ}{\stackrel{\·}{U}}_{n-1}& \mathrm{\Δ}{\stackrel{\·}{U}}_n\end{array}\right]}^T$ For n × 1 dimension matrix, $\mathrm{\Δ}{\stackrel{\·}{U}}_1,\mathrm{\Δ}{\stackrel{\·}{U}}_3,\·\·\·,\mathrm{\Δ}{\stackrel{\·}{U}}_{n-2},{\mathrm{\Δ}\stackrel{\·}{U}}_{n-1},\mathrm{\Δ}{\stackrel{\·}{U}}_n$ Be respectively after the circuit breaker tripping at circuit ij two ends, be numbered the the 1st, 2,3 ..., the voltage variety of n-2, n-1, n transformer station.

The current change quantity of circuit lk after the circuit breaker tripping at wide area backup protection system-computed circuit ij two ends

and judgement whether set up, if set up, wide area backup protection system judges that circuit lk is faulty line, sends trip signal to the circuit breaker at circuit lk two ends; Wherein, l=1 ..., n; K=1 ..., n; N is electricity grid substation total number; z _lkfor the line impedance of circuit lk; I _setfor setting current threshold value;

before circuit breaker tripping for circuit ij two ends, WAMS measures the electric current flowing through on circuit lk; H=[0...1.. ...-1...0] ^tfor n × 1 dimension matrix, in H matrix, capable the 1st column element of l is 1, and in H matrix, capable the 1st column element of k is-1, and other elements are all 0;

after circuit breaker tripping for circuit ij two ends, WAMS measures the electric current flowing through on circuit lk; Circuit lk connects l transformer station and k transformer station; Circuit lk is different circuits from circuit ij.

The inventive method utilizes the existing WAMS of electrical network to realize the synchro measure of the each transformer substation voltage of electrical network, electric current phasor, obtains synchronized data; If there is the tripping operation of electrical network uniline; wide area backup protection system-computed intermediary matrix; calculate matrix of variables; calculate the each transformer substation voltage variable quantity of electrical network matrix; calculate the current change quantity that each line flows of electrical network crossed, utilize current change quantity and the WAMS that each the line flows of electrical network calculating crossed to measure each line current variable quantity formation power network line wide area current protection criterion of electrical network.

The inventive method is in the time that the rear topological structure of electric of electrical network uniline tripping operation changes, directly calculate rear each the current change quantity that line flows is crossed of electrical network uniline tripping operation, whole computational process can complete within the 200ms time, protection quick action, faster than the existing line backup protection algorithm based on this locality amount decision-making, can be by reliable circuit locking before circuit overload is protected misoperation, after effectively preventing the tripping operation of electrical network uniline, trend transfer causes that All other routes overload is excised by mistake, can be by faulty line fast trip before line backup protection action, in time faulty line and electrical network are kept apart, improve the security and stability of operation of power networks.

The foregoing is only preferred embodiment of the present invention; but protection scope of the present invention is not limited to this; any be familiar with those skilled in the art the present invention disclose technical scope in, the variation that can expect easily or replacement, within all should being encompassed in protection scope of the present invention.

Claims (1)

1. the power network line wide area current protection method of revising fast based on admittance matrix, comprises following sequential steps:

(1) wide area backup protection system utilizes the existing WAMS of electrical network to realize the synchro measure of the each transformer substation voltage of electrical network, electric current phasor, and Real-time Obtaining synchronized data, if after the circuit breaker tripping at circuit ij two ends, enter step (2); Wherein, circuit ij connects i transformer station and j transformer station; I=1 ..., n; J=1 ..., n; N is electricity grid substation total number;

(2) wide area backup protection system-computed intermediary matrix W=Y ^-1m; Wherein, Y is grid nodes admittance matrix, for n × n ties up matrix; M=[0...1...-1...0] ^tfor n × 1 dimension matrix, in Metzler matrix, capable the 1st column element of i is 1, and in Metzler matrix, capable the 1st column element of j is-1, and other elements are 0; I=1 ..., n; J=1 ..., n; N is electricity grid substation total number;

(3) wide area backup protection system-computed matrix of variables

wherein, E is unit matrix, is 1 × 1 dimension matrix;

be 1 × n dimension matrix, in J matrix, the 1st row i column element is-y _ij, in J matrix, the 1st row j column element is y _ij, other elements are 0;

before circuit breaker tripping for circuit ij two ends, the each transformer substation voltage phase of the electrical network moment matrix that WAMS measures, is n × 1 dimension matrix; y _ijfor the line admittance of circuit ij;

(4) after the circuit breaker tripping at wide area backup protection system-computed circuit ij two ends, the each transformer substation voltage variable quantity of electrical network matrix $\mathrm{\Δ}\stackrel{\·}{U}=-\mathrm{WZ};$ Wherein, $\mathrm{\Δ}\stackrel{\·}{U}={\left[\begin{array}{ccccccc}\mathrm{\Δ}{\stackrel{\·}{U}}_1& \mathrm{\Δ}{\stackrel{\·}{U}}_2& \mathrm{\Δ}{\stackrel{\·}{U}}_3& \·\·\·& \mathrm{\Δ}{\stackrel{\·}{U}}_{n-2}& \mathrm{\Δ}{\stackrel{\·}{U}}_{n-1}& \mathrm{\Δ}{\stackrel{\·}{U}}_n\end{array}\right]}^T$ For n × 1 dimension matrix, $\mathrm{\Δ}{\stackrel{\·}{U}}_1,\mathrm{\Δ}{\stackrel{\·}{U}}_3,\·\·\·,\mathrm{\Δ}{\stackrel{\·}{U}}_{n-2},{\mathrm{\Δ}\stackrel{\·}{U}}_{n-1},\mathrm{\Δ}{\stackrel{\·}{U}}_n$ Be respectively after the circuit breaker tripping at circuit ij two ends, be numbered the the 1st, 2,3 ..., n-2, n-1, n transformer station voltage variety;

(5) current change quantity of circuit lk after the circuit breaker tripping at wide area backup protection system-computed circuit ij two ends

and judgement

whether set up, if set up, wide area backup protection system judges that circuit lk is faulty line, sends trip signal to the circuit breaker at circuit lk two ends; Wherein, l=1 ..., n; K=1 ..., n; N is electricity grid substation total number; z _lkfor the line impedance of circuit lk; I _setfor setting current threshold value;

before circuit breaker tripping for circuit ij two ends, WAMS measures the electric current flowing through on circuit lk; H=[0...1...-1...0] ^tfor n × 1 dimension matrix, in H matrix, capable the 1st column element of l is 1, and in H matrix, capable the 1st column element of k is-1, and other elements are all 0; after circuit breaker tripping for circuit ij two ends, WAMS measures the electric current flowing through on circuit lk; Circuit lk connects l transformer station and k transformer station; Circuit lk is different circuits from circuit ij.

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