CN103762570B - A kind of power network line relay protecting method that is applicable to dual line fault - Google Patents

Abstract

The present invention relates to a kind of power network line relay protecting method that is applicable to dual line fault. The inventive method is when after dual circuit fault trip occurs electrical network, topological structure of electric changes; just can directly calculate each the current change quantity that line flows is crossed after the dual circuit fault trip of electrical network without revising grid branch admittance matrix, grid nodes incidence matrix; computing time is short; 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 protective relaying maloperation is done; can, by other faulty line fast trip isolation, improve safe operation of electric network stability.

Description

A kind of power network line relay protecting method that is applicable to dual line fault

Technical field

The present invention relates to Relay Protection Technology in Power System field, more particularly, relate to a kind of dual line fault that is applicable toPower network line relay protecting method.

Background technology

The task of relay protection be reflection protected element fault and irregular operating state, according to function can be divided into main protection withBack-up protection. Wherein the fast task of excision protected element fault is only being undertaken in main protection, is not substantially subject to system operation modeImpact. 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 back-up protection far away of adjacent electrical equipment is also being undertaken in back-up protection, owing to existing transforming plant DC power-failMay, this responsibility is to cancel. The information of protection installation place is only reacted in existing electrical network back-up protection, connected by power network topologyThe impact of relation and the method for operation. For ensureing its reliability, have to be configured and adjust according to the harshest situation; For protectingDemonstrate,prove that it is selective, have to sacrifice rapidity and the sensitivity of back-up protection. Because electric network composition is increasingly sophisticated, just cause simultaneouslyFollowing potential safety hazard:

1) back-up protection matching relationship complexity, actuation time is long. When serious, likely do not meet stability of power system desiredCritical clearing time, and then become large power grid security hidden danger.

2) back-up 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 occurProtection mismatch or under-sensitive situation.

3) back-up protection can not be distinguished the trend transfer causing after internal fault and failure removal, and this likely causes heavy load situationUnder back-up protection cascading trip.

In the accident of having a power failure on a large scale, although just occurred that power system back-up protection is according to design principle correct operation, objectivelyBut 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 back-up 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, by measurementThe renewal speed of amount tapered to a few tens of milliseconds by several seconds, had created condition for realizing dynamic process of electrical power system control, made from electricityThe design that the angle of net total optimization is carried out back-up protection becomes possibility.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, a kind of power network line relay that is applicable to dual line fault is providedGuard method. Whether the method can occur effectively to identify All other routes in dual circuit fault trip situation at electrical network and break down,Can, by reliable circuit locking before regular link overload protective relaying maloperation is done, other faulty line fast trips can be isolated,Improve safe operation of electric network stability.

Technical scheme of the present invention is as follows:

A power network line relay protecting method that is applicable to dual line fault, comprises following sequential steps:

1) wide area backup protection system utilizes the existing WAMS of electrical network to realize the same of the each transformer substation voltage of electrical network, electric current phasorPacing amount, Real-time Obtaining synchronized data, if after the breaker tripping at circuit i and circuit j two ends, enter step 2);

Wherein, i=1 ..., n; J=1 ..., n; Circuit i and circuit j are different circuits; N is power network line sum;

2) n between each line current of wide area backup protection system-computed electrical network × n dimension incidence matrix ζ=YA^T(AYA^T)^-1A；

Wherein, Y is grid branch admittance matrix; A is grid nodes incidence matrix;

3) variable quantity of circuit k current flowing after the breaker tripping at wide area backup protection system-computed circuit i and circuit j two ends ${\stackrel{\·}{\mathrm{\ΔI}}}_k=\frac{{\mathrm{\ζ}}_{\mathrm{ki}}+{\mathrm{\ζ}}_{\mathrm{ji}}{\mathrm{\ζ}}_{\mathrm{kj}}}{1-{\mathrm{\ζ}}_{\mathrm{ij}}{\mathrm{\ζ}}_{\mathrm{ji}}}{\stackrel{\·}{I}}_i+\frac{{\mathrm{\ζ}}_{\mathrm{kj}}+{\mathrm{\ζ}}_{\mathrm{ij}}{\mathrm{\ζ}}_{\mathrm{ki}}}{1-{\mathrm{\ζ}}_{\mathrm{ji}}{\mathrm{\ζ}}_{\mathrm{ij}}}{\stackrel{\·}{I}}_j;$

Wherein, ζ_kiFor the capable i column element of k of incidence matrix ζ; ζ_kjFor the capable j column element of k of incidence matrix ζ; ζ_ijForThe capable j column element of i of incidence matrix ζ; ζ_jiFor the capable i column element of j of incidence matrix ζ; Circuit k and circuit j be not forSame circuit; Circuit k and circuit i are different circuits; K=1 ..., n;For the breaker at circuit i and circuit j two ends is not jumpedBefore opening, WAMS measures the electric current flowing through on circuit i;For the breaker at circuit i and circuit j two ends is not before tripping,WAMS measures the electric current flowing through on circuit j;

4) wide area backup protection system judgementWhether set up, if set up, judge that circuit k breaks down,Send action trip signal, the breaker at tripping circuit k two ends; IfSet up, judge that circuit k is normal,Breaker to circuit k two ends sends block signal;

Wherein, I_setFor setting current threshold value;After breaker tripping for circuit i and circuit j two ends, WAMSMeasure the electric current that circuit k flows through;For the breaker at circuit i and circuit j two ends is not before tripping, WAMS measuresThe electric current that circuit k flows through.

Beneficial effect of the present invention is as follows:

First the inventive method utilizes voltage, the electric current phasor of the each transformer station of electrical network existing WAMS synchro measure electrical network,Obtain synchronized data; If there is dual circuit fault trip in electrical network, each line electricity of wide area backup protection system-computed electrical networkIncidence matrix between stream, utilizes the incidence matrix between each line current of electrical network to calculate the electric current change that each line flows of electrical network crossedChange amount, then utilizes the line current variable quantity calculating and the line current variable quantity that actual measurement obtains to form relay protection criterion.The inventive method when after dual circuit fault trip occurs electrical network, topological structure of electric changes, is led without revising grid branchReceiving matrix, grid nodes incidence matrix just can directly calculate after the dual circuit fault trip of electrical network the electric current that each line flows cross and becomeChange amount, computing time is short, protection quick action, faster than the existing line backup protection algorithm based on the decision-making of this locality amount, can beBefore circuit overload protective relaying maloperation work, by reliable circuit locking, can, by other faulty line fast trips isolation, improve electricityNetwork operation security and stability.

Brief description of the drawings

Fig. 1 is the flow chart of method of the present invention.

Detailed description of the invention

Below in conjunction with drawings and Examples, the present invention is described in further detail.

Fig. 1 is the application power network line relay protecting method flow chart that is applicable to dual line fault of the present invention. In the present embodiment,Wide area backup protection system is utilized voltage, the electric current phasor of the each transformer station of electrical network existing WAMS synchro measure electrical network, obtainsPower taking net synchrodata.

If after the breaker tripping at circuit i and circuit j two ends, between each line current of wide area backup protection system-computed electrical networkN × n dimension incidence matrix ζ=YA^T(AYA^T)^-1A; Wherein, Y is grid branch admittance matrix; A is grid nodes incidence matrix;I=1 ..., n; J=1 ..., n; Circuit i and circuit j are different circuits; N is power network line sum.

The variable quantity of circuit k current flowing after the breaker tripping at wide area backup protection system-computed circuit i and circuit j two endsWherein, ζ_kiFor the capable i column element of k of incidence matrix ζ; ζ_kjFor incidence matrixThe capable j column element of k of ζ; ζ_ijFor the capable j column element of i of incidence matrix ζ; ζ_jiFor the capable i row of j of incidence matrix ζElement; Circuit k and circuit j are different circuits; Circuit k and circuit i are different circuits; K=1 ..., n;For circuit i andThe breaker at circuit j two ends is not before tripping, and WAMS measures the electric current flowing through on circuit i;For circuit i and circuit jThe breaker at two ends is not before tripping, and WAMS measures the electric current flowing through on circuit j.

The judgement of wide area backup protection systemWhether set up, if set up, judge that circuit k breaks down, send outGo out to move trip signal, the breaker at tripping circuit k two ends.

The judgement of wide area backup protection systemWhether set up, if set up, judge that circuit k is normal, to circuitThe breaker at k two ends sends block signal; Wherein, I_setFor setting current threshold value;For opening circuit of circuit i and circuit j two endsAfter device tripping, WAMS measures the electric current that circuit k flows through;For the not tripping of breaker at circuit i and circuit j two endsBefore, WAMS measures the electric current that circuit k flows through.

The inventive method when after dual circuit fault trip occurs electrical network, topological structure of electric changes, is propped up without revising electrical networkRoad admittance matrix, grid nodes incidence matrix just can directly calculate each the electricity that line flows is crossed after the dual circuit fault trip of electrical networkStream variable quantity, computing time is short, protection quick action, faster than the existing line backup protection algorithm based on this locality amount decision-making,Can, by reliable circuit locking before circuit overload protective relaying maloperation is done, can, by other faulty line fast trip isolation, carryHigh safe operation of electric network stability.

Above-described embodiment is only for the present invention is described, and not as limitation of the invention. As long as foundation skill of the present inventionArt essence, to above-described embodiment change, modification etc. all will drop in the scope of claim of the present invention.

Claims (1)

1. a power network line relay protecting method that is applicable to dual line fault, is characterized in that, comprises following sequential steps:

1) wide area backup protection system utilizes the existing WAMS of electrical network to realize the same of the each transformer substation voltage of electrical network, electric current phasorPacing amount, Real-time Obtaining synchronized data, if after the breaker tripping at circuit i and circuit j two ends, enter step 2);

Wherein, i=1 ..., n; J=1 ..., n; Circuit i and circuit j are different circuits; N is power network line sum;

2) n between each line current of wide area backup protection system-computed electrical network × n dimension incidence matrix ζ=YA^T(AYA^T)^-1A；

Wherein, Y is grid branch admittance matrix; A is grid nodes incidence matrix;

3) variable quantity of circuit k current flowing after the breaker tripping at wide area backup protection system-computed circuit i and circuit j two ends ${\stackrel{\·}{\mathrm{\ΔI}}}_k=\frac{{\mathrm{\ζ}}_{\mathrm{ki}}+{\mathrm{\ζ}}_{\mathrm{ji}}{\mathrm{\ζ}}_{\mathrm{kj}}}{1-{\mathrm{\ζ}}_{\mathrm{ij}}{\mathrm{\ζ}}_{\mathrm{ji}}}{\stackrel{\·}{I}}_i+\frac{{\mathrm{\ζ}}_{\mathrm{kj}}+{\mathrm{\ζ}}_{\mathrm{ij}}{\mathrm{\ζ}}_{\mathrm{ki}}}{1-{\mathrm{\ζ}}_{\mathrm{ji}}{\mathrm{\ζ}}_{\mathrm{ij}}}{\stackrel{\·}{I}}_j;$

Wherein, ζ_kiFor the capable i column element of k of incidence matrix ζ; ζ_kjFor the capable j column element of k of incidence matrix ζ; ζ_ijForThe capable j column element of i of incidence matrix ζ; ζ_jiFor the capable i column element of j of incidence matrix ζ; Circuit k and circuit j be not forSame circuit; Circuit k and circuit i are different circuits; K=1 ..., n;For the breaker at circuit i and circuit j two ends is not jumpedBefore opening, WAMS measures the electric current flowing through on circuit i;For the breaker at circuit i and circuit j two ends is not before tripping,WAMS measures the electric current flowing through on circuit j;

4) wide area backup protection system judgementWhether set up, if set up, judge that circuit k breaks down,Send action trip signal, the breaker at tripping circuit k two ends; IfSet up, judge that circuit k is normal,Breaker to circuit k two ends sends block signal;

Wherein, I_setFor setting current threshold value;After breaker tripping for circuit i and circuit j two ends, WAMSMeasure the electric current that circuit k flows through;For the breaker at circuit i and circuit j two ends is not before tripping, WAMS measuresThe electric current that circuit k flows through.