CN104332972A - Grid line wide-area backup protection method applicable to single-line tripping - Google Patents

Abstract

The invention discloses a grid line wide-area backup protection method applicable to single-line tripping. The grid line wide-area backup protection method adopts an existing wide-area measuring system of a power grid to synchronously measure voltage and current phasor of various transformer substations of the power grid to obtain synchronous data of the power grid. If the grid single line trips, the wide-area backup protection system calculates system equivalent impedance between two nodes of the tripping line and injection current and voltage variation matrixes of various nodes of the power grid and calculates current variables passing each line, and the calculated current variables of the line and the current variable measured by the wide-area measuring system constitute relay protection reference. By the grid line wide-area backup protection method, when the double lines of the power grid trip and the topological structure of the power grid changes, the current passing each line of the power grid can be directly calculated without rectifying the admittance matrix of the power grid after the double lines of the power grid trip at the same time, the integral calculation process can be completed within 200ms, and protection is fast in action.

Description

Be applicable to uniline tripping operation power network line wide area backup protection method

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to one and be applicable to uniline tripping operation power network line wide area backup protection method.

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 main protection is only responsible for the task of excision protected element fault fast, substantially not by the impact of system operation mode.Along with the application of optical-fibre channel, based on high pressure, the extra high voltage system main protection technology maturation day by day of Two-Terminal Electrical Quantities.And backup protection is also responsible for the task of doing the backup protection far away of adjacent electrical element, owing to there is the possibility of transforming plant DC power-fail, this responsibility to cancel.The information of protection installation place is only reacted in existing electrical network backup protection, by the impact of power network topology annexation and operational mode.For ensureing its reliability, have to be configured according to the harshest situation and adjust; For ensureing its selectivity, the rapidity of sacrifice backup protection of having to and sensitivity.Simultaneously because electric network composition is increasingly sophisticated, just cause following potential safety hazard:

1) backup protection matching relationship is complicated, and operate time is long.Likely do not meet the critical clearing time required by stability of power system time serious, and then become bulk power grid potential safety hazard.

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

3) power flow transfer that causes after can not distinguishing internal fault and failure removal of backup protection, this likely causes the backup protection cascading trip in heavy load situation.

In large-scale blackout, although just occurred that electric power system backup protection is according to design principle correct operation, objectively but accelerates the phenomenon of system crash.Therefore, consider that the backup protection system for damping research of electrical network global information is extremely urgent.

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

Summary of the invention

The object of the invention is to the deficiency overcoming prior art existence, provide one to be applicable to uniline tripping operation power network line wide area backup protection method.The method can by reliable for circuit locking before circuit overload protection misoperation; after effectively preventing electrical network uniline from tripping, power flow transfer causes All other routes overload to be excised by mistake; can 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:

Be applicable to uniline tripping operation power network line wide area backup protection method, it is characterized in that, comprise following sequential steps:

(1) wide area backup protection system utilizes the existing WAMS of electrical network to realize the synchro measure of 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, 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) the system equivalent impedance between wide area backup protection system-computed circuit ij two node wherein, z _ijfor the line impedance of circuit ij; M=[0 ... 1 ...-1 ... 0] ^tfor matrix is tieed up in n × 1, in Metzler matrix, the i-th row the 1st column element is 1, and in Metzler matrix, jth row the 1st column element is-1, and other elements are 0; I=1 ..., n; J=1 ..., n; N is electricity grid substation total number; Y is the grid nodes admittance matrix before the non-tripping of circuit breaker at circuit ij and circuit lk two ends, for n × n ties up matrix; Y ^-1for the inverse matrix of node admittance matrix Y, for n × n ties up matrix; M ^tfor the transposed matrix of Metzler matrix, be that 1 × n ties up matrix; it is 1 × 1 dimension matrix;

(3) wide area backup protection system-computed electrical network each node Injection Current variable quantity matrix wherein, $\stackrel{\·}{I}={\left[\begin{array}{ccccccc}{\stackrel{\·}{I}}_1& {\stackrel{\·}{I}}_2& {\stackrel{\·}{I}}_3& ...& {\stackrel{\·}{I}}_{n-2}& {\stackrel{\·}{I}}_{n-1}& {\stackrel{\·}{I}}_n\end{array}\right]}^T$ For matrix is tieed up in n × 1, be respectively and be numbered the 1st, 2,3 ..., n-2, n-1, n transformer station Injection Current; $\mathrm{\Δ}\stackrel{\·}{I}={\left[\begin{array}{ccccccc}\mathrm{\Δ}{\stackrel{\·}{I}}_1& \mathrm{\Δ}{\stackrel{\·}{I}}_2& \mathrm{\Δ}{\stackrel{\·}{I}}_3& ...& \mathrm{\Δ}{\stackrel{\·}{I}}_{n-2}& \mathrm{\Δ}{\stackrel{\·}{I}}_{n-1}& \mathrm{\Δ}{\stackrel{\·}{I}}_n\end{array}\right]}^T$ For matrix is tieed up in n × 1, after being respectively the circuit breaker tripping at circuit ij two ends, be numbered the 1st, 2,3 ..., n-2, n-1, n transformer station Injection Current variable quantity; N is electricity grid substation total number;

(4) wide area backup protection system-computed electrical network each node voltage variable quantity matrix 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 matrix is tieed up in n × 1, after being respectively the circuit breaker tripping at circuit ij two ends, be numbered 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 judge whether set up, if set up, then wide area backup protection system judges that circuit lk is faulty line, and the circuit breaker to circuit lk two ends sends trip signal; 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, get 0.3 times of circuit lk rated current; for before the circuit breaker tripping at circuit ij two ends, existing WAMS measures the electric current that circuit lk flows through; H=[0 ... 1 ...-1 ... 0] ^tfor matrix is tieed up in n × 1, in H matrix, capable 1st column element of l is that in 1, H matrix, row k the 1st column element is-1, and other elements are all 0; H ^tfor H transpose of a matrix matrix, be that 1 × n ties up matrix; for after the circuit breaker tripping at circuit ij two ends, existing WAMS measures the electric current that circuit lk flows through; Circuit lk connects l transformer station and k transformer station; Circuit lk and circuit ij are different circuit.

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

First the inventive method utilizes the existing WAMS of electrical network to realize the synchro measure of each transformer substation voltage of electrical network, electric current phasor, obtains synchronized data; If there is the tripping operation of electrical network uniline; system equivalent impedance between wide area backup protection system-computed tripping operation circuit two node; calculate electrical network each node Injection Current variable quantity matrix; calculate electrical network each node voltage variable quantity matrix; calculate the current change quantity that the every bar circuit of electrical network flows through, the line current variable quantity that utilization calculates and this line current variable quantity that existing WAMS measures form relaying protection criterion.The inventive method is when the rear topological structure of electric of electrical network uniline tripping operation changes, the current change quantity that flows through of each bar circuit after the tripping operation of electrical network uniline just directly can be calculated without the need to revising grid nodes admittance matrix, whole computational process can complete within the 200ms time, protection act speed is fast, faster than the existing line backup protection algorithm based on this locality amount decision-making, can by reliable for circuit locking before circuit overload protection misoperation, after effectively preventing electrical network uniline from tripping, power flow transfer causes All other routes overload to be excised by mistake, can 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 power network line wide area current protection General layout Plan of the present invention.

Embodiment

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

Fig. 1 is application power network line wide area current protection General layout Plan of the present invention.In Fig. 1, PMU is synchronous phasor measurement unit, system when GPS is pair, 1,2,3, T-1, T, T+1, T+2 ..., n-2, n-1, n be electrical network each transformer station numbering.Wide area backup protection system utilizes the existing WAMS of electrical network to realize the synchro measure of each transformer substation voltage of electrical network, electric current phasor, Real-time Obtaining synchronized data.

System equivalent impedance between wide area backup protection system-computed circuit ij two node

Wherein, z _ijfor the line impedance of circuit ij; M=[0 ... 1 ...-1 ... 0] ^tfor matrix is tieed up in n × 1, in Metzler matrix, the i-th row the 1st column element is 1, and in Metzler matrix, jth row the 1st column element is-1, and other elements are 0; I=1 ..., n; J=1 ..., n; N is electricity grid substation total number; Y is the grid nodes admittance matrix before the non-tripping of circuit breaker at circuit ij and circuit lk two ends, for n × n ties up matrix; Y- ¹for the inverse matrix of node admittance matrix Y, for n × n ties up matrix; M ^tfor the transposed matrix of Metzler matrix, be that 1 × n ties up matrix; it is 1 × 1 dimension matrix.

Wide area backup protection system-computed electrical network each node Injection Current variable quantity matrix wherein, $\stackrel{\·}{I}={\left[\begin{array}{ccccccc}{\stackrel{\·}{I}}_1& {\stackrel{\·}{I}}_2& {\stackrel{\·}{I}}_3& ...& {\stackrel{\·}{I}}_{n-2}& {\stackrel{\·}{I}}_{n-1}& {\stackrel{\·}{I}}_n\end{array}\right]}^T$ For matrix is tieed up in n × 1, be respectively and be numbered the 1st, 2,3 ..., n-2, n-1, n transformer station Injection Current; $\mathrm{\Δ}\stackrel{\·}{I}={\left[\begin{array}{ccccccc}\mathrm{\Δ}{\stackrel{\·}{I}}_1& \mathrm{\Δ}{\stackrel{\·}{I}}_2& \mathrm{\Δ}{\stackrel{\·}{I}}_3& ...& \mathrm{\Δ}{\stackrel{\·}{I}}_{n-2}& \mathrm{\Δ}{\stackrel{\·}{I}}_{n-1}& \mathrm{\Δ}{\stackrel{\·}{I}}_n\end{array}\right]}^T$ For matrix is tieed up in n × 1, after being respectively the circuit breaker tripping at circuit ij two ends, be numbered the 1st, 2,3 ..., n-2, n-1, n transformer station Injection Current variable quantity; N is electricity grid substation total number.

Wide area backup protection system-computed electrical network each node voltage variable quantity matrix 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 matrix is tieed up in n × 1, after being respectively the circuit breaker tripping at circuit ij two ends, be numbered the 1st, 2,3 ..., n-2, n-1, n transformer station voltage variety.

The current change quantity of circuit lk after the circuit breaker tripping at wide area backup protection system-computed circuit ij two ends and judge whether set up, if set up, then wide area backup protection system judges that circuit lk is faulty line, and the circuit breaker to circuit lk two ends sends trip signal.

Wide area backup protection system judges whether set up, if set up, then wide area backup protection system judges that circuit lk is regular link, and the circuit breaker to circuit lk two ends sends block signal.

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, get 0.3 times of circuit lk rated current; for before the circuit breaker tripping at circuit ij two ends, existing WAMS measures the electric current that circuit lk flows through; H=[0 ... 1 ...-1 ... 0] ^tfor matrix is tieed up in n × 1, in H matrix, capable 1st column element of l is that in 1, H matrix, row k the 1st column element is-1, and other elements are all 0; H ^tfor H transpose of a matrix matrix, be that 1 × n ties up matrix; for after the circuit breaker tripping at circuit ij two ends, existing WAMS measures the electric current that circuit lk flows through; Circuit lk connects l transformer station and k transformer station; Circuit lk and circuit ij are different circuit.

The inventive method is when the rear topological structure of electric of electrical network uniline tripping operation changes, the current change quantity that flows through of each bar circuit after the tripping operation of electrical network uniline just directly can be calculated without the need to revising grid nodes admittance matrix, whole computational process can complete within the 200ms time, protection act speed is fast, faster than the existing line backup protection algorithm based on this locality amount decision-making, can by reliable for circuit locking before circuit overload protection misoperation, after effectively preventing electrical network uniline from tripping, power flow transfer causes All other routes overload to be excised by mistake, can 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 thereto; anyly be familiar with those skilled in the art in the technical scope that the present invention discloses, the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.

Claims (1)

1. be applicable to uniline tripping operation power network line wide area backup protection method, it is characterized in that, comprise following sequential steps:

(1) wide area backup protection system wide area backup protection system utilizes the existing WAMS of electrical network to realize the synchro measure of 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, 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) the system equivalent impedance between wide area backup protection system-computed circuit ij two node wherein, z _ijfor the line impedance of circuit ij; M=[0 ... 1 ...-1 ... 0] ^tfor matrix is tieed up in n × 1, in Metzler matrix, the i-th row the 1st column element is 1, and in Metzler matrix, jth row the 1st column element is-1, and other elements are 0; I=1 ..., n; J=1 ..., n; N is electricity grid substation total number; Y is the grid nodes admittance matrix before the non-tripping of circuit breaker at circuit ij and circuit lk two ends, for n × n ties up matrix; Y ^-1for the inverse matrix of node admittance matrix Y, for n × n ties up matrix; M ^tfor the transposed matrix of Metzler matrix, be that 1 × n ties up matrix; it is 1 × 1 dimension matrix.

(3) wide area backup protection system-computed electrical network each node Injection Current variable quantity matrix wherein, $\stackrel{\·}{I}={\left[\begin{array}{ccccccc}{\stackrel{\·}{I}}_1& {\stackrel{\·}{I}}_2& {\stackrel{\·}{I}}_3& ...& {\stackrel{\·}{I}}_{n-2}& {\stackrel{\·}{I}}_{n-1}& {\stackrel{\·}{I}}_n\end{array}\right]}^T$ For matrix is tieed up in n × 1, be respectively and be numbered the 1st, 2,3 ..., n-2, n-1, n transformer station Injection Current; $\mathrm{\Δ}\stackrel{\·}{I}={\left[\begin{array}{ccccccc}\mathrm{\Δ}{\stackrel{\·}{I}}_1& \mathrm{\Δ}{\stackrel{\·}{I}}_2& \mathrm{\Δ}{\stackrel{\·}{I}}_3& ...& \mathrm{\Δ}{\stackrel{\·}{I}}_{n-2}& \mathrm{\Δ}{\stackrel{\·}{I}}_{n-1}& \mathrm{\Δ}{\stackrel{\·}{I}}_n\end{array}\right]}^T$ For matrix is tieed up in n × 1, after being respectively the circuit breaker tripping at circuit ij two ends, be numbered the 1st, 2,3 ..., n-2, n-1, n transformer station Injection Current variable quantity; N is electricity grid substation total number.

(4) wide area backup protection system-computed electrical network each node voltage variable quantity matrix 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 matrix is tieed up in n × 1, after being respectively the circuit breaker tripping at circuit ij two ends, be numbered 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 judge whether set up, if set up, then wide area backup protection system judges that circuit lk is faulty line, and the circuit breaker to circuit lk two ends sends trip signal; 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, get 0.3 times of circuit lk rated current; for before the circuit breaker tripping at circuit ij two ends, existing WAMS measures the electric current that circuit lk flows through; H=[0 ... 1 ...-1 ... 0] ^tfor matrix is tieed up in n × 1, in H matrix, capable 1st column element of l is that in 1, H matrix, row k the 1st column element is-1, and other elements are all 0; H ^tfor H transpose of a matrix matrix, be that 1 × n ties up matrix; for after the circuit breaker tripping at circuit ij two ends, existing WAMS measures the electric current that circuit lk flows through; Circuit lk connects l transformer station and k transformer station; Circuit lk and circuit ij are different circuit.