CN102510071A - Power grid system emergency control method and device - Google Patents

Abstract

The invention discloses a power grid emergency control method which is applicable to a power grid dispatching and control center provided with a wide area measuring system. The method comprises the following steps: utilizing unit transient state kinetic energy before and after failure to analyze interference degree of the unit; weighting the regulation of an electric distance meter in a failure center and the unit; considering an economy and influence factor via a unit important factor, and integrally obtaining unit controllable factors; and carrying out emergency switching operation according to the unit controllable factors in an order from big to small, and improving the efficiency and the validity of the power grid emergency control. In the invention, the efficiency and the real time performance of the emergency control to the power grid are further improved by simplifying power grid system topology, and validity of system transient state destabilization judgment is improved by adopting an energy changing tract geometrical transient state judgment method. The invention also discloses a power grid system emergency control device. Compared with the prior art, the emergency control method provided by the invention can achieve an accurate, reliable and efficient control effect.

Description

A kind of network system emergency control method and device

Technical field

The present invention relates to a kind of network system emergency control method, be applicable to the dispatching of power netwoks control centre of having wide area measurement system (WAMS).

Background technology

Along with economy and technical development, the scale of electric power system progressively increases, and suffers big disturbance such as short trouble and to lose the possibility of transient state angle stability bigger, need take various control measure to make it recover stable.The control of its middle filling machine can change the distribute power in the inertia of being cut node and kinetic energy, the reconfiguration system, is one of major measure of controlling of electrical power system transient angle stability.

The cutter control strategy needs the clear and definite cutter moment, cutter place and cutter amount.Its middle filling machine is set at the control time the earliest that engineering allows constantly, generally depends on the differentiation of transient state unstability constantly.The cutter amount is then closely related with the cutter place, so the cutter place selection is the most important thing.

At present the cutter place selection mainly contains based on the quantity of state index and changes and analyze two classes greatly based on time-domain-simulation.

The first kind is based on time-domain-simulation and engineering experience; Document one " Predicting unstable modes in power systems:theory and computations " (IEEE Trans on Power Systems, 1993 the 8th volume the 1429th page of the 4th phase) select fault clearance constantly or critical excision constantly when the maximum generator of maximum generator, the kinetic energy of acceleration or system's unstability the maximum generator of angular speed as the cutter place.This method has only been analyzed the disturbed degree of unit, does not consider the controllability of units factor, can't provide the validity ordering in cutter place.

Second type depends on stability analysis and associated sensitivity calculating.Like document two " fast algorithm of optimum cutter cutting load scheme under the emergency control " (electric power network technique; 2011 the 35th volume the 82nd page of the 6th phase) be a kind of optimal control problem of nonlinear integer programming with the cutter problem description, according to the Calculation of Sensitivity control place and the controlled quentity controlled variable of generator's power and angle in the time-domain-simulation to control variables.These class methods depend on electrical network rapid modeling analysis after the fault, and fault type, stability analysis and cutter select three big problems to intercouple, and have further increased the complexity of calculating, ageing relatively poor, accuracy is not high.

Vast in territory, the complex structure of large-scale interconnected power system can't fast and effeciently carry out parameter reconstruct and stable emulation after breaking down.For this reason, be badly in need of a kind of rapid and reliable electrical network controllability of units sort method,, reach the purpose of POWER SYSTEM EMERGENCY CONTROL, effectively keep power network safety operation so that combine with existing wide area measurement system (WAMS) effectively.

Summary of the invention

Technical problem to be solved by this invention is to overcome the existing in prior technology deficiency; A kind of network system emergency control method is provided; Can, the transient state unstability, thereby make system return to steady operation apace when appearring in network system for urgent cutter operation provides accurate foundation.

Particularly, the present invention adopts following technical scheme to solve the problems of the technologies described above:

A kind of network system emergency control method is characterized in that, may further comprise the steps:

Steps A, set up network system in advance and simplify topological database;

Step B, when network system breaks down, the geographical position of locking fault point, and mate the distance of fault point fast to each generating set through the simplification topological database that steps A makes up; Whether the real time discriminating network system transient state unstability occurs simultaneously;

Step C, according to the controllability factor gamma of each generating set under the computes fault _i:

${\mathrm{\γ}}_i=\underset{\mathrm{num}\∈\mathrm{Fault}}{\mathrm{\Σ}}{c}_i\·\mathrm{\Δ}{V}_{\mathrm{KE}}\left(\mathrm{num}\right)/d_i,$

Wherein, Δ V _KE(num) be fault moment generating set energy variation, Δ V _KE(num)=V _KE(t _Num+ T)-V _KE(t _Num); Fault differentiates the failure collection that has taken place before the electrical network unstability, c for constantly playing from disturbance identification _iBe the importance factor of i group generating set, num is the fault numbering, t _NumFor fault num takes place constantly, d _iBe the distance of fault point to i group generating set, T is the sampling time;

Step D, like network system the transient state unstability appears, then according to the controllability factor gamma _iOrder is from big to small carried out the cutter operation to each generating set successively, returns stable state until system.

Further, in order to reduce computation complexity, improve the efficient and the real-time of emergency control, the said network system of setting up in advance of steps A is simplified topological database, specifically according to following method:

Steps A 1, according to the difference of region and the dense degree of generating set, the whole network generating set is contracted in main several key node, carry out subregion and simplify the operation, and set up new topology diagram based on the generator subregion;

Steps A 2, through system operation mode and tidal current chart, analyze the main transmission line of network system, and the geographical location information of record important line, do further to simplify to handle;

Steps A 3, utilize the above topology structure chart,, record in the database through the equivalent electrical distance of estimating each bar important line to each generator zone key node of simulation software;

Steps A 4, if during electric network composition generation significant variations, repeat above-mentioned steps.

Whether the network system of real time discriminating described in the step B transient state unstability occurs, can adopt existing the whole bag of tricks.The present invention has adopted a kind of how much transient state unstabilitys of track method of discrimination of taking into account energy variation; This method is on the basis of the unstable method of discrimination of existing transient state based on the phase plane trajectory geometric properties (referring to document " based on the unstable Study of recognition of the transient state of track geometric properties " (Proceedings of the CSEE was rolled up the 16th page of the 4th phase in 2008 the 28th)); The transient state kinetic energy of system and the microvariations amount of transient state gross energy are introduced distinguishing rule, thereby improve the accuracy of differentiating the result.Specifically according to following method:

Step 1, judge that whether network system has disturbance to take place, and in this way, then changes step 2;

Step 2, the generating set in the network system is polymerized to one machine infinity bus system; And make up the merit angle-angular speed of one machine infinity bus system and the phase plane of merit angle-imbalance power, calculate merit angle-angular speed planar obit simulation concavity and convexity index and merit angle-imbalance power planar obit simulation concavity and convexity index;

Step 3, the transient state kinetic energy microvariations amount of calculating one machine infinity bus system and the uneven energy microvariations of transient state amount;

Step 4, judge whether following formula is met, in this way, then judge network system transient state unstability,

$\left\{\begin{array}{c}\mathrm{\τ}\left(t\right)>0\\ \mathrm{\μ}\left(t\right)>0\\ \frac{{\mathrm{dV}}_{\mathrm{KE}}\left(t\right)}{\mathrm{dt}}>0\\ \frac{\mathrm{d\ΔV}\left(t\right)}{\mathrm{dt}}>0\end{array}\right.,$

In the formula, τ (t), μ (t), Merit angle-angular speed planar obit simulation concavity and convexity index, merit angle-imbalance power planar obit simulation concavity and convexity index, transient state kinetic energy microvariations amount, the uneven energy microvariations of the transient state amount of representing one machine infinity bus system respectively, V _KEBe the transient state kinetic energy of one machine infinity bus system, Δ V is the uneven energy of one machine infinity bus system transient state.

Preferably, said generating set in the network system is polymerized to one machine infinity bus system, specifically according to following method:

Step 201, according to the computes disturbance composite power-angle of each generator constantly:

${\mathrm{\δ}}_{\mathrm{com}}={\mathrm{\δ}}_0\left(t\right)+100\mathrm{\π}[\mathrm{\ω}\left(t\right)+\frac{\mathrm{\ΔP}\left(t\right)}{2{\mathrm{\τ}}_g}\mathrm{\Δ}{t}_{\mathrm{set}}]\mathrm{\Δ}{t}_{\mathrm{set}},$

In the formula, δ ₀(t) for generator's power and angle constantly takes place in disturbance, generator imbalance power constantly, τ take place for disturbance in Δ P (t) _gBe the inertia time constant of generator, Δ t _SetBe the time set value;

Step 202, with the ordering of each generator composite power-angle, carry out the difference computing of adjacent composite power-angle according to following formula, obtain clearance angle Δ δ _Comij:

Δδ _comij(t+kT)＝|δ _comi(t+kT)-δ _comj(t+kT)|，

In the formula, i, j are the generator numbering, and k is a positive integer;

Step 203, the clearance angle that step 202 is obtained carry out sorting operation again, get place, angle, maximal clearance as hiving off the interval, and the operation of hiving off is divided into the leading crowd and the crowd that lags behind with the generator in the network system;

Step 204, respectively the leading crowd and the crowd that lags behind are carried out polymerization, it is following to merge formula:

$\left\{\begin{array}{c}{M}_A=\underset{i\∈S}{\mathrm{\Σ}}{M}_i\\ {\mathrm{\δ}}_A(t+\mathrm{kT})=\frac{\underset{i\∈A}{\mathrm{\Σ}}{H}_i{\mathrm{\δ}}_i(t+\mathrm{kT})}{\underset{i\∈A}{\mathrm{\Σ}}{H}_i}\\ P_{\mathrm{mA}}(t+\mathrm{kT})=\frac{\underset{i\∈A}{\mathrm{\Σ}}{H}_i{P}_{\mathrm{mi}}(t+\mathrm{kT})}{\underset{i\∈A}{\mathrm{\Σ}}{H}_i}\\ P_{\mathrm{eA}}(t+\mathrm{kT})=\frac{\underset{i\∈A}{\mathrm{\Σ}}{H}_i{P}_{\mathrm{ei}}(t+\mathrm{kT})}{\underset{i\∈A}{\mathrm{\Σ}}{H}_i}\end{array}\right.$ $\left\{\begin{array}{c}{M}_S=\underset{i\∈S}{\mathrm{\Σ}}{M}_j\\ {\mathrm{\δ}}_S(t+\mathrm{kT})=\frac{\underset{i\∈S}{\mathrm{\Σ}}{H}_j{\mathrm{\δ}}_j(t+\mathrm{kT})}{\underset{i\∈S}{\mathrm{\Σ}}{H}_j}\\ P_{\mathrm{mS}}(t+\mathrm{kT})=\frac{\underset{i\∈S}{\mathrm{\Σ}}{H}_j{P}_{\mathrm{mj}}(t+\mathrm{kT})}{\underset{i\∈S}{\mathrm{\Σ}}{H}_j}\\ P_{\mathrm{eA}}(t+\mathrm{kT})=\frac{\underset{i\∈A}{\mathrm{\Σ}}{H}_j{P}_{\mathrm{ej}}(t+\mathrm{kT})}{\underset{i\∈A}{\mathrm{\Σ}}{H}_j}\end{array}\right.$

In the formula, M _A, δ _A(t+kT), P _MA(t+kT), P _EA(t+kT) be respectively the equivalent unit moment of inertia of leading crowd, merit angle, equivalent mechanical output, equivalent electromagnetic power, M _S, δ _S(t+kT), P _MS(t+kT), P _ES(t+kT) be respectively the lag behind equivalent moment of inertia of crowd, unit merit angle, equivalent mechanical output, equivalent electromagnetic power, A and S are respectively the leading crowd and the crowd's that lags behind generator set, H _iThe inertia of i platform generator among the leading crowd of expression, H _jThe inertia of j platform generator among the expression hysteresis crowd;

Step 205, by the following formula high-ranking military officer earlier crowd and the equivalent unit of crowd that lags behind be transformed to one machine infinity bus system:

$\left\{\begin{array}{c}M=\frac{M_S{M}_A}{M_S+M_A}\\ {\mathrm{\δ}}_{\mathrm{OMIB}}(t+\mathrm{kT})={\mathrm{\δ}}_S(t+\mathrm{kT})-{\mathrm{\δ}}_A(t+\mathrm{kT})\\ P_{\mathrm{mOMIB}}(t+\mathrm{kT})=P_{\mathrm{mS}}(t+\mathrm{kT})-P_{\mathrm{mA}}(t+\mathrm{kT})\\ P_{\mathrm{eOMIB}}(t+\mathrm{kT})=P_{\mathrm{eS}}(t+\mathrm{kT})-P_{\mathrm{eA}}(t+\mathrm{kT})\end{array}\right.$

In the formula, M, δ _OMIB(t+kT), P _MOMIB(t+kT), P _EOMIB(t+kT) be respectively moment of inertia, merit angle, mechanical output, the electromagnetic power of one machine infinity bus system;

The angular velocity omega of step 206, judgement one machine infinity bus system _OMIBWhether satisfy following formula, in this way, then with current time generator's power and angle and imbalance power numerical value substitution step 201, hiving off reevaluates; As not, then continue next step,

ω _OMIB(t+kT)＝δ _OMIB(t+kT)-δ _OMIB(t+(k-1)T)＝0。

Further, the merit angle-angular speed of said structure one machine infinity bus system and the phase plane of merit angle-imbalance power are calculated merit angle-angular speed planar obit simulation concavity and convexity index and merit angle-imbalance power planar obit simulation concavity and convexity index; Specifically according to following method:

Step 207, according to said one machine infinity bus system angular speed continuously constantly, set up observation vector:

Y=[ω _OMIB(t), ω _OMIB(t+T), L, ω _OMIB(t+ (b-1) T)] ^T, as the match input, b is the match point number;

Step 208, to set up one machine infinity bus system angular speed polynomial function following:

ω(t)＝a ₀+a ₁t+a ₂t ²+L+a _nt ⁿ，

In the formula, n is the polynomial fitting exponent number, A _N=[a ₀, a ₁, a ₂, L, a _n] ^TBe model parameter vector;

Step 209, utilize least square method to calculate the parameter vector A of above-mentioned polynomial function _N:

A _N＝[H ^TH] ^-1H ^T·Y

In the formula: $H=\left[\begin{array}{ccccc}1& 0& 0& \mathrm{<figure-callout\; id="0"\; label="L"\; filenames="111114175624.png,111114175639.png"\; state="\{\{state\}\}">L</figure-callout>}& 0\\ 1& T& T^2& L& T^n\\ L& L& L& L& L\\ 1& (b-1)T& (b-1)T^2& L& (b-1)T^n\end{array}\right];$

Step 2010, utilize the angular speed polynomial function of match, merit angle-angular speed planar obit simulation concavity and convexity index τ, the merit angle-imbalance power planar obit simulation concavity and convexity index μ of calculating one machine infinity bus system according to following formula respectively:

$\mathrm{\&tau;}\left(t\right)={\left(\frac{{\mathrm{\&omega;}}^{\&prime;}\left(t\right)}{\mathrm{\&omega;}\left(t\right)}\right)}^{\&prime;},$

$\left\{\begin{array}{c}\frac{\mathrm{d\&Delta;P}\left(t\right)}{d{\mathrm{\&delta;}}_{\mathrm{OMIB}}\left(t\right)}=\frac{\mathrm{\&Delta;P}\left(t\right)-\mathrm{\&Delta;P}(t-T)}{{\mathrm{\&delta;}}_{\mathrm{OMIB}}\left(t\right)-{\mathrm{\&delta;}}_{\mathrm{OMIB}}(t-T)}=\mathrm{\&Delta;}{P}^{\&prime;}\left(t\right)\\ \mathrm{\&mu;}\left(t\right)=\frac{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="111114175629.png,111114175639.png"\; state="\{\{state\}\}">d</figure-callout>}}^2\mathrm{\&Delta;P}\left(t\right)}{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="111114175629.png,111114175639.png"\; state="\{\{state\}\}">d</figure-callout>}}^2{\mathrm{\&delta;}}_{\mathrm{OMIB}}\left(t\right)}=\frac{\mathrm{\&Delta;}{P}^{\&prime;}\left(t\right)-\mathrm{\&Delta;}{P}^{\&prime;}(t-T)}{{\mathrm{\&delta;}}_{\mathrm{OMIB}}\left(t\right)-{\mathrm{\&delta;}}_{\mathrm{OMIB}}(t-T)}\end{array}\right.,$

In the formula, Δ P (t) is that one machine infinity bus system is at t imbalance power constantly, Δ P (t)=P _MOMIB(t)-P _EOMIB(t).

Preferably, saidly judge whether network system has disturbance to take place, specifically according to following method:

Step 101, utilize phasor measurement unit to gather in real time each generator electromagnetic power in the said network system;

Step 102, respectively according to the continuous constantly microvariations amount Δ P of each generator electromagnetic power of computes _e, obtain each generator electromagnetic power microvariations time series { Δ P _e(t+T), Δ P _e(t+2T) L}:

ΔP _e(t+T)＝P _e(t+T)-P _e(t)，

In the formula, P _e(t) be t generator electromagnetic power constantly, T is the sampling time;

Step 103, whether be met to judge whether network system has disturbance to take place,, judge that then network system has disturbance to take place as satisfying according to following formula:

|ΔP _e(t+mT)|＞K|ΔP _e(t+(m-1)T)|

In the formula: greater than 1 sudden change threshold coefficient, m is the integer greater than 1 to K for preset.

According to invention thinking of the present invention, also can obtain a kind of network system emergence control, this device comprises: the disturbance identification module, according to the real-time measuring data of phasor measurement unit output in the said network system, judge whether network system has disturbance to take place;

The polymerization module of hiving off; When the disturbance identification module judges that network system has disturbance to take place,, finally aggregate into one machine infinity bus system to the operation of hiving off of each unit of electrical network; And, differentiate the operation of whether need hiving off again through polymerization unit track real-time assessment group information;

The transient stability identification module; The one machine infinity bus system that provides according to the polymerization module of hiving off; Calculate the uneven energy microvariations of its merit angle-angular speed planar obit simulation concavity and convexity index, merit angle-imbalance power planar obit simulation concavity and convexity index, transient state kinetic energy microvariations amount, transient state amount, and whether be met whether transient state unstability of real-time analysis network system according to following condition:

$\left\{\begin{array}{c}\mathrm{\&tau;}\left(t\right)>0\\ \mathrm{\&mu;}\left(t\right)>0\\ \frac{{\mathrm{dV}}_{\mathrm{KE}}\left(t\right)}{\mathrm{dt}}>0\\ \frac{\mathrm{d\&Delta;V}\left(t\right)}{\mathrm{dt}}>0\end{array}\right.,$

In the formula, τ (t), μ (t),

Merit angle-angular speed planar obit simulation concavity and convexity index, merit angle-imbalance power planar obit simulation concavity and convexity index, transient state kinetic energy microvariations amount, the uneven energy microvariations of the transient state amount of representing one machine infinity bus system respectively, V _KEBe the transient state kinetic energy of one machine infinity bus system, Δ V is the uneven energy of one machine infinity bus system transient state;

The fault location module when the disturbance identification module judges that network system has disturbance to take place, is caught the coherent signal of relay protection device on each circuit of electrical network, locking fault scene;

Disturbed unit order module is according to the controllability factor gamma of each generating set under the computes fault _i, and according to the controllability factor gamma _iOrder from big to small sorts to generating set:

${\mathrm{\&gamma;}}_i=\underset{\mathrm{num}\&Element;\mathrm{Fault}}{\mathrm{\&Sigma;}}{c}_i\&CenterDot;\mathrm{\&Delta;}{V}_{\mathrm{KE}}\left(\mathrm{num}\right)/d_i,$

Wherein, Δ V _KE(num) be fault moment generating set energy variation, Δ V _KE(num)=V _KE(t _Num+ T)-V _KE(t _Num); Fault differentiates the failure collection that has taken place before the electrical network unstability, c for constantly playing from disturbance identification _iBe the importance factor of i group generating set, num is the fault numbering, t _NumFor fault num takes place constantly, d _iBe the distance of fault point to i group generating set;

The emergency control module, when transient stability identification module decision-making system transient state unstability, the clooating sequence of exporting according to disturbed unit order module carries out the cutter operation, and is stable until system restoration.

Unit transient state kinetic energy was analyzed the disturbed degree of unit before and after the present invention utilized fault, and the electrical distance of weighting and defect center is taken into account the controlled of unit, and considers economy and influencing factor through the unit importance factor, comprehensively obtains the controllability of units factor; And carry out urgent cutter according to controllability factor order from big to small and operate, improved the efficient and the validity of electrical network emergency control.The present invention is also through simplifying further efficient and the real-time that has improved emergency control to the network system topology; And adopt how much transient state unstabilitys of track method of discrimination of taking into account energy variation, improved the validity that system's transient state unstability is differentiated.

Description of drawings

Fig. 1 is the structural representation of network system emergence control of the present invention;

Fig. 2 is the workflow diagram of disturbance identification module in the network system emergence control of the present invention;

Fig. 3 is the workflow diagram of transient state unstability identification module in the network system emergence control of the present invention;

Fig. 4 is the IEEE39 node system that adopts in the emulation experiment;

Fig. 5 is that the IEEE39 node system is stablized the example analogous diagram;

Fig. 6 is an IEEE39 node system unstability example analogous diagram;

Fig. 7 is the IEEE39 node system unstability example analogous diagram after the inventive method differentiation and the control.

Embodiment

Below in conjunction with accompanying drawing technical scheme of the present invention is elaborated:

The stable control technology of the incident that is based on that adopt in conventional defence line, electric power system second road if the accident that predefined fault is concentrated takes place in the system of monitoring, is then carried out corresponding safety and stability control operation according to the priori Policy Table.Its advantage be with strong points, reliability is high, but if the outer degradation failure of anticipation takes place in system, will can not take safeguard measure, cause large area blackout then.The present invention is based on the merit angle and the power information of the wide area measurement of PMU (phasor measurement unit)/WAMS (wide area measurement system); Purpose is to take precautions against system's transient state unstability that the big disturbance beyond the control range of defence line, two roads causes; And, instruct cutter operation in emergency circumstances through to disturbed unit ordering.

Network system emergence control structure of the present invention is as shown in Figure 1, comprising:

The disturbance identification module according to each generator electromagnetic power real-time measuring data of phasor measurement unit output, judges whether network system has disturbance to take place;

The polymerization module of hiving off; When the disturbance identification module judges that network system has disturbance to take place,, and finally aggregate into one machine infinity bus system to the operation of hiving off of each unit of electrical network; And, differentiate the operation of whether need hiving off again through polymerization unit track real-time assessment group information;

The transient stability identification module according to the equivalent one-of-a-kind system that the polymerization module of hiving off provides, calculates the stability indicator that comprises that track is concavo-convex and transient state energy is relevant, the transient stability characteristic of real-time analyzer;

The fault location module when the disturbance identification module judges that network system has disturbance to take place, is caught the coherent signal of relay protection device on each circuit of electrical network, locking fault scene;

Disturbed unit order module, the abort situation information that obtains according to the fault location module, through estimating the electrical distance at each unit distance fault center based on the network topological diagram of unit subregion, and the weighting Considering Energy changes and importance degree sorts;

The emergency control module, when transient stability identification module decision-making system transient state unstability, the clooating sequence of exporting according to disturbed unit order module carries out the cutter operation, and is stable until system restoration.

Below, the overall operation structure chart according to Fig. 1 is described in detail concrete steps of the present invention.

(1) judge whether network system has disturbance to take place:

Utilize phasor measurement unit (PMU) to gather each generator electromagnetic power in real time, continuous moment electromagnetic power numerical value is carried out calculus of differences, obtain microvariations amount Δ P _e, as the input of disturbance identification module:

ΔP _e(t+T)＝P _e(t+T)-P _e(t)

In the formula: P _e(t) be t generator electromagnetic power constantly, T is the sampling time.

If electromagnetic power microvariations time series { Δ P _e(t+T), Δ P _e(t+2T) saltus step takes place in L}, and then illustrative system receives big disturbing influence, and the power-balance of generator is destroyed.Used criterion is:

|ΔP _e(t+mT)|＞K|ΔP _e(t+(m-1)T)|

In the formula: K is sudden change threshold coefficient, and preferably value is 5, and m is the integer greater than 1.

Disturbance identification dependence diagram is as shown in Figure 2.

(2) the electrical network unit hive off polymerization with reevaluate:

After disturbance identification module judgement system breaks down, get into the polymerization module of hiving off.

At first according to the computes disturbance composite power-angle of each generator constantly:

${\mathrm{\&delta;}}_{\mathrm{com}}={\mathrm{\&delta;}}_0\left(t\right)+100\mathrm{\&pi;}[\mathrm{\&omega;}\left(t\right)+\frac{\mathrm{\&Delta;P}\left(t\right)}{2{\mathrm{\&tau;}}_g}\mathrm{\&Delta;}{t}_{\mathrm{set}}]\mathrm{\&Delta;}{t}_{\mathrm{set}}$

In the formula: δ ₀(t) for generator's power and angle constantly takes place in disturbance, generator imbalance power constantly, τ take place for disturbance in Δ P (t) _gBe the inertia time constant of generator, Δ t _SetBe the time set value, preferably value is 100 milliseconds.

The difference computing of adjacent composite power-angle is carried out according to following formula in composite power-angle ordering back, obtain clearance angle Δ δ _Comij:

Δδ _comij(t+kT)＝|δ _comi(t+kT)-δ _comj(t+kT)|

In the formula, i, j are the generator numbering, and k is a positive integer.

The clearance angle that aforementioned calculation is obtained carries out sorting operation again, gets place, angle, maximal clearance as hiving off the interval, and the operation of hiving off is divided into the leading crowd and the crowd that lags behind with the generator in the network system.

Carry out polymerization to two groups respectively, the merging formula is:

$\left\{\begin{array}{c}{M}_A=\underset{i\&Element;S}{\mathrm{\&Sigma;}}{M}_i\\ {\mathrm{\&delta;}}_A(t+\mathrm{kT})=\frac{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_i{\mathrm{\&delta;}}_i(t+\mathrm{kT})}{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_i}\\ P_{\mathrm{mA}}(t+\mathrm{kT})=\frac{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_i{P}_{\mathrm{mi}}(t+\mathrm{kT})}{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_i}\\ P_{\mathrm{eA}}(t+\mathrm{kT})=\frac{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_i{P}_{\mathrm{ei}}(t+\mathrm{kT})}{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_i}\end{array}\right.$ $\left\{\begin{array}{c}{M}_S=\underset{i\&Element;S}{\mathrm{\&Sigma;}}{M}_j\\ {\mathrm{\&delta;}}_S(t+\mathrm{kT})=\frac{\underset{i\&Element;S}{\mathrm{\&Sigma;}}{H}_j{\mathrm{\&delta;}}_j(t+\mathrm{kT})}{\underset{i\&Element;S}{\mathrm{\&Sigma;}}{H}_j}\\ P_{\mathrm{mS}}(t+\mathrm{kT})=\frac{\underset{i\&Element;S}{\mathrm{\&Sigma;}}{H}_j{P}_{\mathrm{mj}}(t+\mathrm{kT})}{\underset{i\&Element;S}{\mathrm{\&Sigma;}}{H}_j}\\ P_{\mathrm{eA}}(t+\mathrm{kT})=\frac{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_j{P}_{\mathrm{ej}}(t+\mathrm{kT})}{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_j}\end{array}\right.$

In the formula: M _A, δ _A(t+kT), P _MA(t+kT), P _EA(t+kT) be respectively the equivalent unit moment of inertia of leading crowd, merit angle, equivalent mechanical output, equivalent electromagnetic power, M _S, δ _S(t+kT), P _MS(t+kT), P _Es(t+kT) be respectively the lag behind equivalent moment of inertia of crowd, unit merit angle, equivalent mechanical output, equivalent electromagnetic power, A and S are respectively the leading crowd and the crowd's that lags behind generator set, H _iBe the inertia of i platform generator among the leading crowd, H _jInertia for j platform generator among the crowd that lags behind.

After the complex electric network system equivalent is two machine systems, further it is transformed to one machine infinity bus system (OMIB) by following formula.

$\left\{\begin{array}{c}M=\frac{M_S{M}_A}{M_S+M_A}\\ {\mathrm{\&delta;}}_{\mathrm{OMIB}}(t+\mathrm{kT})={\mathrm{\&delta;}}_S(t+\mathrm{kT})-{\mathrm{\&delta;}}_A(t+\mathrm{kT})\\ P_{\mathrm{mOMIB}}(t+\mathrm{kT})=P_{\mathrm{mS}}(t+\mathrm{kT})-P_{\mathrm{mA}}(t+\mathrm{kT})\\ P_{\mathrm{eOMIB}}(t+\mathrm{kT})=P_{\mathrm{eS}}(t+\mathrm{kT})-P_{\mathrm{eA}}(t+\mathrm{kT})\end{array}\right.$

In the formula: M, δ _OMIB(t+kT), P _MOMIB(t+kT), P _EOMIB(t+kT) be respectively moment of inertia, the merit angle of equivalent unit, mechanical output, electromagnetic power.

According to above-mentioned equivalent unit merit angle track, if equivalent unit angular velocity omega _OMIBSatisfy following formula:

ω _OMIB(t+kT)＝δ _OMIB(t+kT)-δ _OMIB(t+(k-1)T)＝0

Judgement polymerization merit angle finishes once to wave process, need reappraise to the situation of hiving off, and utilizes each generator's power and angle numerical value of current time to carry out the above-mentioned operation of hiving off, and carries out the one machine infinity bus system equivalence again; If do not satisfy, then keep the information of hiving off.

(3) the electrical network transient stability is analyzed:

The utilization equivalent one-of-a-kind system that the polymerization module obtains of hiving off is calculated continuously equivalent unit angular speed constantly, sets up observation vector: Y=[ω _OMIB(t), ω _OMIB(t+T), L, ω _OMIB(t+ (b-1) T)] ^T, import as match; B is the match point number, preferably gets 5-10.

Set up equivalent unit angular speed polynomial function:

ω(t)＝a ₀+a ₁t+a ₂t ²+L+a _nt ⁿ

In the formula: n is the polynomial fitting exponent number, preferably gets 2, A _N=[a ₀, a ₁, a ₂, L, a _n] ^TBe model parameter vector.

Utilize least square method evaluator function parameters vector A _N:

A _N＝[H ^TH] ^-1H ^T·Y

In the formula: $H=\left[\begin{array}{ccccc}1& 0& 0& \mathrm{<figure-callout\; id="0"\; label="L"\; filenames="111114175624.png,111114175639.png"\; state="\{\{state\}\}">L</figure-callout>}& 0\\ 1& T& T^2& L& T^n\\ L& L& L& L& L\\ 1& (b-1)T& (b-1)T^2& L& (b-1)T^n\end{array}\right]$

Utilize the angular speed polynomial function of match, calculate merit angle-angular speed planar obit simulation concavity and convexity index τ:

$\mathrm{\&tau;}\left(t\right)={\left(\frac{{\mathrm{\&omega;}}^{\&prime;}\left(t\right)}{\mathrm{\&omega;}\left(t\right)}\right)}^{\&prime;}$

Computing system imbalance power sequence Δ P (t), and Δ P (t+T), L}:

ΔP(t)＝P _mOMIB(t)-P _eOMIB(t)

Through calculus of differences, calculate merit angle-imbalance power planar obit simulation concavity and convexity index μ:

$\left\{\begin{array}{c}\frac{\mathrm{d\&Delta;P}\left(t\right)}{d{\mathrm{\&delta;}}_{\mathrm{OMIB}}\left(t\right)}=\frac{\mathrm{\&Delta;P}\left(t\right)-\mathrm{\&Delta;P}(t-T)}{{\mathrm{\&delta;}}_{\mathrm{OMIB}}\left(t\right)-{\mathrm{\&delta;}}_{\mathrm{OMIB}}(t-T)}=\mathrm{\&Delta;}{P}^{\&prime;}\left(t\right)\\ \mathrm{\&mu;}\left(t\right)=\frac{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="111114175629.png,111114175639.png"\; state="\{\{state\}\}">d</figure-callout>}}^2\mathrm{\&Delta;P}\left(t\right)}{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="111114175629.png,111114175639.png"\; state="\{\{state\}\}">d</figure-callout>}}^2{\mathrm{\&delta;}}_{\mathrm{OMIB}}\left(t\right)}=\frac{\mathrm{\&Delta;}{P}^{\&prime;}\left(t\right)-\mathrm{\&Delta;}{P}^{\&prime;}(t-T)}{{\mathrm{\&delta;}}_{\mathrm{OMIB}}\left(t\right)-{\mathrm{\&delta;}}_{\mathrm{OMIB}}(t-T)}\end{array}\right.$

Computing system kinetic energy microvariations amount:

$\frac{{\mathrm{dV}}_{\mathrm{KE}}\left(t\right)}{\mathrm{dt}}=M{\mathrm{\&omega;}}^{\&prime;}\left(t\right)\mathrm{\&omega;}\left(t\right)$

In the formula: V _KEBe system's transient state kinetic energy.

The uneven energy microvariations of computing system transient state numerical value:

$\frac{\mathrm{d\&Delta;V}\left(t\right)}{\mathrm{dt}}=\mathrm{M\&omega;}\left(t\right){\mathrm{\&omega;}}^{\&prime;}\left(t\right)-\mathrm{\&Delta;P\&omega;}\left(t\right)$

In the formula: Δ V is the uneven energy of system's transient state.

Transient state unstability condition for identification is:

$\left\{\begin{array}{c}\mathrm{\&tau;}\left(t\right)>0\\ \mathrm{\&mu;}\left(t\right)>0\\ \frac{{\mathrm{dV}}_{\mathrm{KE}}\left(t\right)}{\mathrm{dt}}>0\\ \frac{\mathrm{d\&Delta;V}\left(t\right)}{\mathrm{dt}}>0\end{array}\right.,$

If satisfy following formula, then judge etching system transient state unstability this moment.Above-mentioned transient state unstability identification process is as shown in Figure 3.

(4) the electrical distance topology is calculated:

After disturbance identification module judgement system breaks down, get into the fault location module, utilize the relay protection device of installing on the circuit, the topology location of monitoring fault origination point.

When electrical network receives big disturbing influence, through catching the coherent signal of circuit protective relaying device, the geographical position of locking fault point.Call the network system of setting up in advance and simplify topological database: according to the difference of region and the dense degree of generator; The whole network unit is carried out subregion to simplify the operation; And analyze important transmission line through tidal current chart, calculated off-line obtains the electrical distance of Area Node to important line.

Carry out matching operation with circuit geographical position in the database, extract the electrical distance of this line scan pickup coil side to each Area Node.

If the fault point is j, geographical recently coupling is circuit k, and then the electrical distance estimated value in generator i ∈ p zone is:

d _ij＝d _kp

d _KpCan from database, extract, be used for the electrical distance weighted calculation.

It is pointed out that the fault match point is positioned at direct current and send end as if network generation direct current transmission fault.

(5) disturbed unit is integrated ordered:

Calculate fault moment unit energy variation:

ΔV _KE(num)＝V _KE(t _num+T)-V _KE(t _num)

In the formula: num is the fault numbering, t _NumFor fault num takes place constantly.

Take into account fault location module output earth fault distance and think the factors such as unit importance that define, calculate the controllability factor gamma of disturbed unit i under the cascading failure _i:

${\mathrm{\&gamma;}}_i=\underset{\mathrm{num}\&Element;\mathrm{Fault}}{\mathrm{\&Sigma;}}{c}_i\&CenterDot;\mathrm{\&Delta;}{V}_{\mathrm{KE}}\left(\mathrm{num}\right)/d_i$

In the formula: Fault differentiates the failure collection that has taken place before the electrical network unstability for constantly playing from disturbance identification, and c is the unit importance factor.

Sort according to the disturbed order of severity of each generating set, promptly according to the controllability factor gamma _iOrder from big to small sorts to each generating set.

(6) emergency control operation:

When transient stability identification module decision-making system transient state unstability, the clooating sequence of exporting according to disturbed unit order module carries out the cutter operation successively, and is stable until system restoration.

Compliance test result:

In order to test the validity of institute of the present invention extracting method, use the inventive method IEEE39 node system different faults situation has been carried out simulating, verifying.

At first, the IEEE39 node system is carried out division operation, 10 generators are divided into 5 sections, as shown in Figure 4.And do topology and simplify processing: each generator is contracted on the nearest Area Node.It is following that fault is set:

Fault 1: circuit 3-4 bus 3 side generation three-phase shortcircuits, trouble duration is 0-0.2s.(stablizing example)

Merit angular response curve is as shown in Figure 5, utilizes the inventive method real-time analyzer transient stability, in the simulation process of 2s, does not differentiate the transient state unstability, is consistent with actual conditions.

Fault 2: circuit 11-10 bus 11 side generation three-phase shortcircuits, trouble duration is 0-0.3s.(unstability example)

Merit angular response curve is as shown in Figure 6; The transient stability identification module of the inventive method is in 1.15s judgement system transient state unstability; Utilize the disturbed unit order module output result of the inventive method; At the maximum unit of above-mentioned moment excision controllability is unit under 39 nodes in the subregion 1, and system returns stable state, and is as shown in Figure 7.Reached the purpose of accurate identification and correct control.

The present invention can be used for the dispatching control center of electrical networks at different levels, based on wide area measurement system, realizes real time discriminating and emergency control to electric power system transient stability.

Claims (10)

1. a network system emergency control method is characterized in that, may further comprise the steps:

Steps A, set up network system in advance and simplify topological database;

Step B, when network system breaks down, the geographical position of locking fault point, and mate the distance of fault point fast to each generating set through the simplification topological database that steps A makes up; Whether the real time discriminating network system transient state unstability occurs simultaneously;

Step C, according to the controllability factor gamma of each generating set under the computes fault _i:

${\mathrm{\&gamma;}}_i=\underset{\mathrm{num}\&Element;\mathrm{Fault}}{\mathrm{\&Sigma;}}{c}_i\&CenterDot;\mathrm{\&Delta;}{V}_{\mathrm{KE}}\left(\mathrm{num}\right)/d_i,$

Wherein, Δ V _KE(num) be fault moment generating set energy variation, Δ V _KE(num)=V _KE(t _Num+ T)-V _KE(t _Num);

Fault differentiates the failure collection that has taken place before the electrical network unstability, c for constantly playing from disturbance identification _iBe the importance factor of i group generating set, num is the fault numbering, t _NumFor fault num takes place constantly, d _iBe the distance of fault point to i group generating set, T is the sampling time;

Step D, like network system the transient state unstability appears, then according to the controllability factor gamma _iOrder is from big to small carried out the cutter operation to each generating set successively, returns stable state until system.

2. network system emergency control method according to claim 1 is characterized in that, the said network system of setting up in advance of steps A is simplified topological database, specifically according to following method:

Steps A 1, according to the difference of region and the dense degree of generating set, the whole network generating set is contracted in main several key node, carry out subregion and simplify the operation, and set up new topology diagram based on the generator subregion;

Steps A 2, through system operation mode and tidal current chart, analyze the main transmission line of network system, and the geographical location information of record important line, do further to simplify to handle;

Steps A 3, utilize the above topology structure chart,, record in the database through the equivalent electrical distance of estimating each bar important line to each generator zone key node of simulation software;

Steps A 4, if during electric network composition generation significant variations, repeat above-mentioned steps.

3. network system emergency control method according to claim 1 is characterized in that whether the network system of real time discriminating described in the step B transient state unstability occurs, specifically according to following method:

Step 1, judge that whether network system has disturbance to take place, and in this way, then changes step 2;

Step 2, the generating set in the network system is polymerized to one machine infinity bus system; And make up the merit angle-angular speed of one machine infinity bus system and the phase plane of merit angle-imbalance power, calculate merit angle-angular speed planar obit simulation concavity and convexity index and merit angle-imbalance power planar obit simulation concavity and convexity index;

Step 3, the transient state kinetic energy microvariations amount of calculating one machine infinity bus system and the uneven energy microvariations of transient state amount;

Step 4, judge whether following formula is met, in this way, then judge network system transient state unstability,

$\left\{\begin{array}{c}\mathrm{\&tau;}\left(t\right)>0\\ \mathrm{\&mu;}\left(t\right)>0\\ \frac{{\mathrm{dV}}_{\mathrm{KE}}\left(t\right)}{\mathrm{dt}}>0\\ \frac{\mathrm{d\&Delta;V}\left(t\right)}{\mathrm{dt}}>0\end{array}\right.,$

In the formula, τ (t), μ (t),

Merit angle-angular speed planar obit simulation concavity and convexity index, merit angle-imbalance power planar obit simulation concavity and convexity index, transient state kinetic energy microvariations amount, the uneven energy microvariations of the transient state amount of representing one machine infinity bus system respectively, V _KEBe the transient state kinetic energy of one machine infinity bus system, Δ V is the uneven energy of one machine infinity bus system transient state.

4. like the said network system emergency control method of claim 3, it is characterized in that, said generating set in the network system is polymerized to one machine infinity bus system, specifically according to following method:

Step 201, according to the computes disturbance composite power-angle of each generator constantly:

${\mathrm{\&delta;}}_{\mathrm{com}}={\mathrm{\&delta;}}_0\left(t\right)+100\mathrm{\&pi;}[\mathrm{\&omega;}\left(t\right)+\frac{\mathrm{\&Delta;P}\left(t\right)}{2{\mathrm{\&tau;}}_g}\mathrm{\&Delta;}{t}_{\mathrm{set}}]\mathrm{\&Delta;}{t}_{\mathrm{set}},$

In the formula, δ ₀(t) for generator's power and angle constantly takes place in disturbance, generator imbalance power constantly, τ take place for disturbance in Δ P (t) _gBe the inertia time constant of generator, Δ t _SetBe the time set value;

Step 202, with the ordering of each generator composite power-angle, carry out the difference computing of adjacent composite power-angle according to following formula, obtain clearance angle Δ δ _Comij:

Δδ _comij(t+kT)＝|δ _comi(t+kT)-δ _comj(t+kT)|，

In the formula, i, j are the generator numbering, and k is a positive integer;

Step 203, the clearance angle that step 202 is obtained carry out sorting operation again, get place, angle, maximal clearance as hiving off the interval, and the operation of hiving off is divided into the leading crowd and the crowd that lags behind with the generator in the network system;

Step 204, respectively the leading crowd and the crowd that lags behind are carried out polymerization, it is following to merge formula:

$\left\{\begin{array}{c}{M}_A=\underset{i\&Element;S}{\mathrm{\&Sigma;}}{M}_i\\ {\mathrm{\&delta;}}_A(t+\mathrm{kT})=\frac{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_i{\mathrm{\&delta;}}_i(t+\mathrm{kT})}{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_i}\\ P_{\mathrm{mA}}(t+\mathrm{kT})=\frac{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_i{P}_{\mathrm{mi}}(t+\mathrm{kT})}{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_i}\\ P_{\mathrm{eA}}(t+\mathrm{kT})=\frac{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_i{P}_{\mathrm{ei}}(t+\mathrm{kT})}{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_i}\end{array}\right.$ $\left\{\begin{array}{c}{M}_S=\underset{i\&Element;S}{\mathrm{\&Sigma;}}{M}_j\\ {\mathrm{\&delta;}}_S(t+\mathrm{kT})=\frac{\underset{i\&Element;S}{\mathrm{\&Sigma;}}{H}_j{\mathrm{\&delta;}}_j(t+\mathrm{kT})}{\underset{i\&Element;S}{\mathrm{\&Sigma;}}{H}_j}\\ P_{\mathrm{mS}}(t+\mathrm{kT})=\frac{\underset{i\&Element;S}{\mathrm{\&Sigma;}}{H}_j{P}_{\mathrm{mj}}(t+\mathrm{kT})}{\underset{i\&Element;S}{\mathrm{\&Sigma;}}{H}_j}\\ P_{\mathrm{eA}}(t+\mathrm{kT})=\frac{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_j{P}_{\mathrm{ej}}(t+\mathrm{kT})}{\underset{i\&Element;A}{\mathrm{\&Sigma;}}{H}_j}\end{array}\right.$

In the formula, M _A, δ _A(t+kT), P _MA(T+kT), P _EA(t+kT) be respectively the equivalent unit moment of inertia of leading crowd, merit angle, equivalent mechanical output, equivalent electromagnetic power, M _S, δ _S(t+kT), P _MS(T+kT), P _ES(t+kT) be respectively the lag behind equivalent moment of inertia of crowd, unit merit angle, equivalent mechanical output, equivalent electromagnetic power, A and S are respectively the leading crowd and the crowd's that lags behind generator set, H _iThe inertia of i platform generator among the leading crowd of expression, H _jThe inertia of j platform generator among the expression hysteresis crowd;

Step 205, by the following formula high-ranking military officer earlier crowd and the equivalent unit of crowd that lags behind be transformed to one machine infinity bus system:

$\left\{\begin{array}{c}M=\frac{M_S{M}_A}{M_S+M_A}\\ {\mathrm{\&delta;}}_{\mathrm{OMIB}}(t+\mathrm{kT})={\mathrm{\&delta;}}_S(t+\mathrm{kT})-{\mathrm{\&delta;}}_A(t+\mathrm{kT})\\ P_{\mathrm{mOMIB}}(t+\mathrm{kT})=P_{\mathrm{mS}}(t+\mathrm{kT})-P_{\mathrm{mA}}(t+\mathrm{kT})\\ P_{\mathrm{eOMIB}}(t+\mathrm{kT})=P_{\mathrm{eS}}(t+\mathrm{kT})-P_{\mathrm{eA}}(t+\mathrm{kT})\end{array}\right.$

In the formula, M, δ _OMIB(t+kT), P _MOMIB(t+kT), P _EOMIB(t+kT) be respectively moment of inertia, merit angle, mechanical output, the electromagnetic power of one machine infinity bus system;

The angular velocity omega of step 206, judgement one machine infinity bus system _OMIBWhether satisfy following formula, in this way, then with current time generator's power and angle and imbalance power numerical value substitution step 201, hiving off reevaluates; As not, then continue next step,

ω _OMIB(t+kT)＝δ _OMIB(t+kT)-δ _OMIB(t+(k-1)T)＝0。

5. like the said network system emergency control method of claim 4, it is characterized in that said time set value Δ t _SetValue be 100 milliseconds.

6. like the said network system emergency control method of claim 4; It is characterized in that; Merit angle-the angular speed of said structure one machine infinity bus system and the phase plane of merit angle-imbalance power are calculated merit angle-angular speed planar obit simulation concavity and convexity index and merit angle-imbalance power planar obit simulation concavity and convexity index; Specifically according to following method:

Step 207, according to said one machine infinity bus system angular speed continuously constantly, set up observation vector:

Y=[ω _OMIB(t), ω _OMIB(t+T), L, ω _OMIB(t+ (b-1) T)] ^T, as the match input, b is the match point number;

Step 208, to set up one machine infinity bus system angular speed polynomial function following:

ω(t)＝a ₀+a ₁t+a ₂t ²+L+a _nt ⁿ，

In the formula, n is the polynomial fitting exponent number, A _N=[a ₀, a ₁, a ₂, L, a _n] ^TBe model parameter vector;

Step 209, utilize least square method to calculate the parameter vector A of above-mentioned polynomial function _N:

A _N＝[H ^TH] ^-1H ^T·Y

In the formula: $H=\left[\begin{array}{ccccc}1& 0& 0& L& 0\\ 1& T& T^2& L& T^n\\ L& L& L& L& L\\ 1& (b-1)T& (b-1)T^2& L& (b-1)T^n\end{array}\right];$

Step 2010, utilize the angular speed polynomial function of match, merit angle-angular speed planar obit simulation concavity and convexity index τ, the merit angle-imbalance power planar obit simulation concavity and convexity index μ of calculating one machine infinity bus system according to following formula respectively:

$\mathrm{\&tau;}\left(t\right)={\left(\frac{{\mathrm{\&omega;}}^{\&prime;}\left(t\right)}{\mathrm{\&omega;}\left(t\right)}\right)}^{\&prime;},$

$\left\{\begin{array}{c}\frac{\mathrm{d\&Delta;P}\left(t\right)}{d{\mathrm{\&delta;}}_{\mathrm{OMIB}}\left(t\right)}=\frac{\mathrm{\&Delta;P}\left(t\right)-\mathrm{\&Delta;P}(t-T)}{{\mathrm{\&delta;}}_{\mathrm{OMIB}}\left(t\right)-{\mathrm{\&delta;}}_{\mathrm{OMIB}}(t-T)}=\mathrm{\&Delta;}{P}^{\&prime;}\left(t\right)\\ \mathrm{\&mu;}\left(t\right)=\frac{d^2\mathrm{\&Delta;P}\left(t\right)}{d^2{\mathrm{\&delta;}}_{\mathrm{OMIB}}\left(t\right)}=\frac{\mathrm{\&Delta;}{P}^{\&prime;}\left(t\right)-\mathrm{\&Delta;}{P}^{\&prime;}(t-T)}{{\mathrm{\&delta;}}_{\mathrm{OMIB}}\left(t\right)-{\mathrm{\&delta;}}_{\mathrm{OMIB}}(t-T)}\end{array}\right.,$

In the formula, Δ P (t) is that one machine infinity bus system is at t imbalance power constantly, Δ P (t)=P _MOMIB(t)-P _EOMIB(t).

7. like the said network system emergency control method of claim 6, it is characterized in that said polynomial fitting exponent number n gets 2, the span of match point number b is 5-10.

8. like the said network system emergency control method of claim 3, it is characterized in that saidly judge whether network system has disturbance to take place, specifically according to following method:

Step 101, utilize phasor measurement unit to gather in real time each generator electromagnetic power in the said network system;

Step 102, respectively according to the continuous constantly microvariations amount Δ P of each generator electromagnetic power of computes _e, obtain each generator electromagnetic power microvariations time series { Δ P _e(t+T), Δ P _e(t+2T) L}:

ΔP _e(t+T)＝P _e(t+T)-P _e(t)，

In the formula, P _e(t) be t generator electromagnetic power constantly, T is the sampling time;

Step 103, whether be met to judge whether network system has disturbance to take place,, judge that then network system has disturbance to take place as satisfying according to following formula:

|ΔP _e(t+mT)|＞K|ΔP _e(t+(m-1)T)|

In the formula: greater than 1 sudden change threshold coefficient, m is the integer greater than 1 to K for preset.

9. like the said network system emergency control method of claim 8, it is characterized in that the value of said sudden change threshold COEFFICIENT K is 5.

10. a network system emergence control is characterized in that, comprising:

The disturbance identification module according to the real-time measuring data of phasor measurement unit output in the said network system, judges whether network system has disturbance to take place;

The polymerization module of hiving off; When the disturbance identification module judges that network system has disturbance to take place,, finally aggregate into one machine infinity bus system to the operation of hiving off of each unit of electrical network; And, differentiate the operation of whether need hiving off again through polymerization unit track real-time assessment group information;

The transient stability identification module; The one machine infinity bus system that provides according to the polymerization module of hiving off; Calculate the uneven energy microvariations of its merit angle-angular speed planar obit simulation concavity and convexity index, merit angle-imbalance power planar obit simulation concavity and convexity index, transient state kinetic energy microvariations amount, transient state amount, and whether be met whether transient state unstability of real-time analysis network system according to following condition:

$\left\{\begin{array}{c}\mathrm{\&tau;}\left(t\right)>0\\ \mathrm{\&mu;}\left(t\right)>0\\ \frac{{\mathrm{dV}}_{\mathrm{KE}}\left(t\right)}{\mathrm{dt}}>0\\ \frac{\mathrm{d\&Delta;V}\left(t\right)}{\mathrm{dt}}>0\end{array}\right.,$

In the formula, τ (t), μ (t),

Merit angle-angular speed planar obit simulation concavity and convexity index, merit angle-imbalance power planar obit simulation concavity and convexity index, transient state kinetic energy microvariations amount, the uneven energy microvariations of the transient state amount of representing one machine infinity bus system respectively, V _KEBe the transient state kinetic energy of one machine infinity bus system, Δ V is the uneven energy of one machine infinity bus system transient state;

The fault location module when the disturbance identification module judges that network system has disturbance to take place, is caught the coherent signal of relay protection device on each circuit of electrical network, locking fault scene;

Disturbed unit order module is according to the controllability factor gamma of each generating set under the computes fault _i, and according to the controllability factor gamma _iOrder from big to small sorts to generating set:

${\mathrm{\&gamma;}}_i=\underset{\mathrm{num}\&Element;\mathrm{Fault}}{\mathrm{\&Sigma;}}{c}_i\&CenterDot;\mathrm{\&Delta;}{V}_{\mathrm{KE}}\left(\mathrm{num}\right)/d_i,$

Wherein, Δ V _KE(num) be fault moment generating set energy variation, Δ V _KE(num)=V _KE(t _Num+ T)-V _KE(t _Num); Fault differentiates the failure collection that has taken place before the electrical network unstability, c for constantly playing from disturbance identification _iBe the importance factor of i group generating set, num is the fault numbering, t _NumFor fault num takes place constantly, d _iBe the distance of fault point to i group generating set;

The emergency control module, when transient stability identification module decision-making system transient state unstability, the clooating sequence of exporting according to disturbed unit order module carries out the cutter operation, and is stable until system restoration.

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