CN103779853A - Grid circuit overload maloperation-preventing relay protection method based on wide-area information - Google Patents

Abstract

The invention discloses a grid circuit overload maloperation-preventing relay protection method based on wide-area information. According to the method, an existing wide-area measuring system of a grid is used for synchronously measuring the phasor quantity of the voltages and the phasor quantity of the currents of all transformer substations at first; if a grid single circuit trips, a wide-area backup protection system sequentially calculates the corrected impedance, the corrected admittance and the compensation voltage; voltages of all nodes of the grid of which the circuit has not tripped and the compensation voltage are superposed to obtain the voltage phasor quantities of all transformer substations of the grid which tripped; the currents flowing through all circuits in the grid are calculated and combined with circuit currents measured by the existing wide-area measuring system to form overload maloperation-preventing protection criteria. According to the grid circuit overload maloperation-preventing relay protection method based on the wide-area information, the protection action speed is high, the circuits can be reliably shut before ciruit overload protection maloperation occurs, other circuits are protected against overload and mistaken cutting, wherein the overload is caused by transferring of the currents after the grid single circuit tripped, and the large-area power failure of the grid is effectively prevented.

Description

Power network line overload faulty action preventing relay protecting method based on Wide-area Measurement Information

Technical field

The present invention relates to Relay Protection Technology in Power System field, specifically relate to a kind of power network line overload faulty action preventing relay protecting method based on Wide-area Measurement Information.

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 invention provides a kind of power network line overload faulty action preventing relay protecting method based on Wide-area Measurement Information; after utilizing the existing WAMS of electrical network to realize the tripping operation of electrical network uniline, trend shifts the relay protection function that causes circuit overload false action-proof, and it has overcome the deficiencies in the prior art described in background technology.

The technical scheme adopting that the present invention solves its technical problem is:

Power network line overload faulty action preventing relay protecting method based on Wide-area Measurement Information, it comprises following sequential steps:

Step 1, wide area backup protection system utilizes the existing WAMS of electrical network to realize the synchro measure of the each transformer substation voltage phasor 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;

Step 2, wide area backup protection system-computed correction impedance M ^ty ^-1m-zi _j; Wherein: zi _jfor the line impedance of circuit ij; Y is electrical network admittance 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; M ^tfor the transposed matrix of Metzler matrix;

Step 3, wide area backup protection system-computed correction admittance M (M ^ty ^-1m-z _ij) ^-1m ^t; Wherein: zi _jfor the line impedance of circuit ij; Y is electrical network admittance 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 all 0; I=1 ..., n; J=1 ..., n; N is electricity grid substation total number; M ^tfor the transposed matrix of Metzler matrix;

Step 4, wide area backup protection system-computed bucking voltage

wherein: n is electricity grid substation total number;

for n × 1 dimension matrix,

be respectively and be numbered the the 1st, 2,3 ..., n-2, n-1, n transformer station Injection Current phasor;

Step 5, the voltage phasor of the each transformer station of electrical network after the circuit breaker tripping at wide area backup protection system-computed circuit ij two ends $\stackrel{\·}{U}=Y^{-1}\stackrel{\·}{I}-Y^{-1}M{\left(M^T{Y}^{-1}{M-z}_{\mathrm{ij}}\right)}^{-1}{M}^T{Y}^{-1}\stackrel{\·}{I};$ Wherein: $\stackrel{\·}{U}{=\left[\begin{array}{ccccccc}{\stackrel{\·}{U}}_1& {\stackrel{\·}{U}}_2& {\stackrel{\·}{U}}_3& ...& {\stackrel{\·}{U}}_{n-2}& {\stackrel{\·}{U}}_{n-1}& {\stackrel{\·}{U}}_n\end{array}\right]}^T$ For n × 1 dimension matrix,

be respectively and be numbered the the 1st, 2,3 after the circuit breaker tripping at circuit ij two ends ..., n-2, n-1, n transformer station voltage phasor;

Step 6, the electric current flowing through on 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, sends block signal to the circuit breaker at circuit lk two ends, prevent circuit overload protection misoperation if judging that circuit lk is regular link; 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;

after circuit breaker tripping for circuit ij two ends, existing WAMS measures the electric current flowing through on circuit lk; Circuit lk connects l transformer station and k transformer station; be respectively the voltage phasor of l transformer station after the circuit breaker tripping at circuit ij two ends, k transformer station.

The technical program is compared with background technology, and its tool has the following advantages:

After the present invention utilizes the existing WAMS of electrical network to realize uniline tripping operation, electric network swim shifts the relay protection function that causes circuit overload false action-proof.The inventive method is when after the tripping of electrical network uniline, topological structure of electric changes, just can directly calculate each the electric current that line flows is crossed after the tripping of electrical network uniline without revising electrical network admittance matrix, 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, effectively prevent the generation of electric grid large area power cut accident.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the invention will be further described.

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

Embodiment

Please refer to Fig. 1,

Wide area backup protection system utilizes the existing WAMS of electrical network to realize the synchro measure of the each transformer substation voltage phasor 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 correction impedance M ^ty ^-1m-zi _j; Wherein: circuit ij connects i transformer station and j transformer station; I=1 ..., n; J=1 ..., n; N is electricity grid substation total number; Zi _jfor the line impedance of circuit ij; Y is electrical network admittance 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; M ^tfor the transposed matrix of Metzler matrix;

And then, wide area backup protection system-computed correction admittance M (M ^ty ^-1m-z _ij) ^-1m ^t; Wherein: zi _jfor the line impedance of circuit ij; Y is electrical network admittance 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 all 0; I=1 ..., n; J=1 ..., n; N is electricity grid substation total number; M ^tfor the transposed matrix of Metzler matrix;

And then, wide area backup protection system-computed bucking voltage wherein: n is electricity grid substation total number;

for n × 1 dimension matrix,

be respectively and be numbered the the 1st, 2,3 ..., n-2, n-1, n transformer station Injection Current phasor;

And then, the voltage phasor of the each transformer station of electrical network after the circuit breaker tripping at wide area backup protection system-computed circuit ij two ends $\stackrel{\·}{U}=Y^{-1}\stackrel{\·}{I}-Y^{-1}M{\left(M^T{Y}^{-1}{M-z}_{\mathrm{ij}}\right)}^{-1}{M}^T{Y}^{-1}\stackrel{\·}{I};$ Wherein: $\stackrel{\·}{U}{=\left[\begin{array}{ccccccc}{\stackrel{\·}{U}}_1& {\stackrel{\·}{U}}_2& {\stackrel{\·}{U}}_3& ...& {\stackrel{\·}{U}}_{n-2}& {\stackrel{\·}{U}}_{n-1}& {\stackrel{\·}{U}}_n\end{array}\right]}^T$ For n × 1 dimension matrix,

be respectively and be numbered the the 1st, 2,3 after the circuit breaker tripping at circuit ij two ends ..., n-2, n-1, n transformer station voltage phasor;

Finally, the electric current flowing through on 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, sends block signal to the circuit breaker at circuit lk two ends, prevent circuit overload protection misoperation if judging that circuit lk is regular link; 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;

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

be respectively the voltage phasor of l transformer station after the circuit breaker tripping at circuit ij two ends, k transformer station.

After the present invention utilizes the existing WAMS of electrical network to realize uniline tripping operation, electric network swim shifts the relay protection function that causes circuit overload faulty action preventing.The inventive method is when after the tripping of electrical network uniline, topological structure of electric changes, just can directly calculate each the electric current that line flows is crossed after the tripping of electrical network uniline without revising electrical network admittance matrix, 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, effectively prevent the generation of electric grid large area power cut accident.

The above, only for preferred embodiment of the present invention, therefore can not limit according to this scope of the invention process, the equivalence of doing according to the scope of the claims of the present invention and description changes and modifies, and all should still belong in the scope that the present invention contains.

Claims (1)

1. the power network line overload faulty action preventing relay protecting method based on Wide-area Measurement Information, is characterized in that, comprises following sequential steps:

Step 1, wide area backup protection system utilizes the existing WAMS of electrical network to realize the synchro measure of the each transformer substation voltage phasor 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;

Step 2, wide area backup protection system-computed correction impedance M ^ty ^-1m-zi _j; Wherein: zi _jfor the line impedance of circuit ij; Y is electrical network admittance 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; M ^tfor the transposed matrix of Metzler matrix;

Step 3, wide area backup protection system-computed correction admittance M (M ^ty ^-1m-z _ij) ^-1m ^t; Wherein: zi _jfor the line impedance of circuit ij; Y is electrical network admittance 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 all 0; I=1 ..., n; J=1 ..., n; N is electricity grid substation total number;

Step 4, wide area backup protection system-computed bucking voltage

wherein: n is electricity grid substation total number;

for n × 1 dimension matrix,

be respectively and be numbered the the 1st, 2,3 ..., n-2, n-1, n transformer station Injection Current phasor;

Step 5, the voltage phasor of the each transformer station of electrical network after the circuit breaker tripping at wide area backup protection system-computed circuit ij two ends $\stackrel{\·}{U}=Y^{-1}\stackrel{\·}{I}-Y^{-1}M{\left(M^T{Y}^{-1}{M-z}_{\mathrm{ij}}\right)}^{-1}{M}^T{Y}^{-1}\stackrel{\·}{I};$ Wherein: $\stackrel{\·}{U}={\left[\begin{array}{ccccccc}{\stackrel{\·}{U}}_1& {\stackrel{\·}{U}}_2& {\stackrel{\·}{U}}_3& ...& {\stackrel{\·}{U}}_{n-2}& {\stackrel{\·}{U}}_{n-1}& {\stackrel{\·}{U}}_n\end{array}\right]}^T$ For n × 1 dimension matrix,

be respectively and be numbered the the 1st, 2,3 after the circuit breaker tripping at circuit ij two ends ..., n-2, n-1, n transformer station voltage phasor;

Step 6, the electric current flowing through on 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, sends block signal to the circuit breaker at circuit lk two ends, prevent circuit overload protection misoperation if judging that circuit lk is regular link; 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;

after circuit breaker tripping for circuit ij two ends, existing WAMS measures the electric current flowing through on circuit lk; Circuit lk connects l transformer station and k transformer station; be respectively the voltage phasor of l transformer station after the circuit breaker tripping at circuit ij two ends, k transformer station.

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