CN102723712A - Method for improving transient stability analysis efficiency of electric power system - Google Patents

Abstract

The invention discloses a method for improving a transient stability analysis efficiency of an electric power system and relates to the field of the electric power system. The method comprises the following steps of: initializing element parameters of the electric power system and inputting data of the electric power system; selecting a network topology state, a generator state and a load level of the electric power system, and determining an operation state of the electric power system; carrying out Monte Carlo sampling selection on the operation state of the electric power system to form a fault sampling sequence; utilizing a task distribution method facing to a multiprocessor parallel system and distributing the fault sampling sequence; carrying out transient stability analysis on a fault sample based on an energy function method by each processor; receiving a result returned by a processor by a main processor and storing the result into a database; and when the fault sampling sequence X is finished, calculating the possibility index of the transient stability of the electric power system and outputting the result. The method disclosed by the invention meets the requirements of instantaneity of information of the electric power system and improves the analysis efficiency and the safety of the electric power system.

Description

A kind of method that improves the power system transient stability analysis efficiency

Technical field

The present invention relates to field of power, relate in particular to a kind of method that improves the power system transient stability analysis efficiency.Specifically, relate to strategy and the implementation method that adopts transient energy function and Monte-Carlo method to improve large-scale electrical power system transient stability analysis efficiency.

Background technology

After power system transient stability was meant that system stands large disturbance suddenly, can each synchronous machine continue to keep the ability of synchronous operation.Usually the disturbance of being considered comprises the unexpected variation of the various short troubles of generation, excision heavy-duty generator or transmission facility and some load etc.Electric power system is a various dimensions system at random; Not only to suffer the type of fault, the place of generation etc. be at random in system; And there is randomness in the action situation of protecting behind the state, fault of system during fault and operations staff to Fault Processing result etc., and the great majority in the electric power system lose load condition all with system dynamically or transient behavior relevant.Because Deterministic Methods is only paid attention to the most seriously, the most believable accident, it is too conservative that result of calculation seems.From the angle of operation, existing equipment is not fully utilized; From point of planning view, cause unnecessary repeated construction.Therefore, in the fail-safe analysis field of electric power system, receive great concern based on uncertain transient stability analytical method.

The transient stability analytical method is the key of carrying out electric power system transient stability, has determined precision of analysis and analysis efficiency.The hybrid algorithm that existing power power system transient stability property analytical method adopts time-domain-simulation method and direct method to combine mostly, this hybrid algorithm is a kind of practical power system transient stability analytical method that recent two decades grows up ^[1]

The inventor finds to exist at least in the prior art following shortcoming and defect in realizing process of the present invention:

Existing transient stability analytical method realizes complicated in the Computer Simulation of large-scale electrical power system; Though accuracy is higher; But owing to be difficult in advance when know when carrying out system emulation and need restart system emulation in the fault, consuming time longer usually, and analysis efficiency is low ^[2]Make and to find the fault that electric power system exists timely, reduced the fail safe of electric power system.

Summary of the invention

The invention provides a kind of method that improves the power system transient stability analysis efficiency; The present invention has satisfied the analysis of electric power system safety on line and the warning aspect demand to information real-time property; Improved the fail safe of analysis efficiency and electric power system, seen hereinafter for details and describe:

A kind of method that improves the power system transient stability analysis efficiency said method comprising the steps of:

(1) the power system component parameter is carried out initialization, the input electric power system data;

(2) network topology state, generator state and the load level of electric power system are selected, confirmed operation states of electric power system;

(3) carry out the Monte Carlo sampling through said operation states of electric power system and select, form fault sampled sequence X=(x ₁, x ₂..., x _n);

(4) employing is towards the method for allocating tasks of parallel multiprocessor system, to said fault sampled sequence X=(x ₁, x ₂..., x _n) distribute;

(5) each is sampled to fault based on energy function from processor and carries out the transient stability analysis;

(6) primary processor receives to each said result who passes back from processor, and the result is saved in database;

(7) judge whether said fault sampled sequence X accomplishes, if, execution in step (8); If not, execution in step (4);

(8) calculate the probability level of electric power system transient stability, and export the result.

Saidly carry out Monte Carlo sampling through said operation states of electric power system and select, form fault sampled sequence X=(x ₁, x ₂..., x _n) specifically comprise:

1) using the Monte Carlo samples to fault element, fault type and fault clearing time;

2) obtain the fault sample mode x of the k time electric power system _k, 1≤k≤n;

3) judge said fault sample mode x _kWhether be included among the existing said fault sampled sequence X, if, to said fault sample mode x _kAgain the selection of sampling; If, do not add among the said fault sampled sequence X, and make k=k+1;

4) judge whether k equals n, if, execution in step (4); If not, execution in step 1), wherein, n representes the simulation times of sampling.

Said each based on energy function the transient stability analysis is carried out in fault sampling from processor and is specifically comprised:

1) current system running state being carried out trend calculates; Judge whether and to cross the border because of element fault causes the operation constraint; Comprise that generator reactive crosses the border, busbar voltage is crossed the border, circuit overload or trend do not restrain; If, adjustment generator output or change of load level, and carry out the adjusted trend of running status again and calculate; If not, execution in step 2);

2) said operation states of electric power system is carried out stability analysis, with said fault sample mode x _kCarry out emulation for disturbance, judge whether electric power system is stable, if, then being designated as type one, implication is said fault sample mode x _kFollowing power system stability, and change step 5); If, do not calculate the transient state energy nargin NEM (P of electric power system ₀), execution in step 3);

3) from preset stabilizing measures, select said fault sample mode x _kStabilizing measures scheme P ₁, carry out stability analysis emulation, and calculate the transient state energy nargin NEM (P of electric power system ₁);

4) based on total injecting power balance principle, through energy function method calculation stability measure control cutting load amount;

5) with said fault sample mode x _kSend to said primary processor with the transient stability types results.

Said transient state energy nargin NEM (P ₀) be specially:

$\mathrm{NEM}\left(P_0\right)=\frac{1}{2}\underset{i=1}{\overset{m}{\mathrm{\Σ}}}{\widetilde{\mathrm{\ω}}}_i^2-\frac{1}{2}\underset{j=1}{\overset{T-1}{\mathrm{\Σ}}}\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\left\{\right[{\mathrm{\θ}}_i\left(t_{j+1}\right)-{\mathrm{\θ}}_i\left(t_j\right)]\×[a_i\left(\mathrm{\θ}\left(t_{j+1}\right)\right)+a_i\left(\mathrm{\θ}\left(t_j\right)\right)\left]\right\}$

M is the generator number of participating in operation in the system;

For taking under the P stabilizing measures controlled quentity controlled variable situation i platform generator with respect to the angular speed in the center of inertia; T constantly takes place from fault in T _ClTo failure removal moment t _ClThe transient stability analysis emulation step number of+Δ t; θ _i(t _j) expression with the transient stability simulation process in t _jCorresponding constantly i platform generator's power and angle; θ _i(t _J+1) expression with the transient stability simulation process in t _J+1Corresponding constantly i platform generator's power and angle; a _i(θ (t _j)) expression t _jThe angular acceleration of moment i platform generator; a _i(θ (t _J+1)) expression t _J+1The angular acceleration of moment i platform generator.

Said based on total injecting power balance principle, through energy function method calculation stability measure control cutting load amount, specifically comprise:

4a) according to said transient state energy nargin NEM (P ₀) and NEM (P ₁), adopt interpolation method of energy margin to ask for best cutter capacity P _{2, gen}

Wherein, ${\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA00001824835200051.png"\; state="\{\{state\}\}">P</figure-callout>}}_{2,\mathrm{Gen}}=0.5[P_1+\frac{-\mathrm{NEM}\left(P_1\right)(P_0-P_1)}{\mathrm{NEM}\left(P_0\right)-\mathrm{NEM}\left(P_1\right)}]$

P ₀Stabilizing measures is not adopted in expression;

4b) based on total injecting power balance principle, according to said best cutter capacity P _{2, gen}, calculation stability measure scheme P ₂In corresponding cutting load amount P _{2, load}=P _{2, gen}

4c) based on the maximum stabilizing measures amount P that allows of fault under said preset stabilizing measures and the current state _Max, judge whether P _{2, gen}+ P _{2, load}>=P _Max, if then get P _{2, gen}=P _{2, load}=0.5P _MaxIf not, do not adjust;

4d) according to the said stabilizing measures scheme P that obtains ₂, electric power system is contained the stability simulation that the cutter cutting load is operated, judge whether electric power system is stable, if, being designated as type two, implication is that electric power system is in controlled instability status; If not, be designated as type three, implication is that uncontrollable unstability takes place in electric power system.

The beneficial effect of technical scheme provided by the invention is:

(1) employing is based on the energy function method of angle mould plate technique; Avoided the pseudo-fault that energy margin is asked in the hybrid algorithm in the past to continue the track integral process; Greatly accelerated the estimating velocity of transient stability, and maintenance level that provides each sample states transient stability and margin of safety that can be quantitative.

(2) Monte-Carlo method and energy function method and management and running rule are combined closely, promptly can simulate the ruuning situation of electric power system conscientiously, can accelerate estimating velocity through ignoring secondary cause again.

(3) the transient stability risk evaluation result that is obtained has and can quantize, convenient characteristic relatively.This method can not only provide the power failure probability; System cuts down the electric weight index, and system's unstability probability and frequency can also provide the power system transient stability degree; Actual physics variablees such as system stability measure amount, power failure cost can be described from levels such as system, user's (load point), elements.

(4) make full use of the parallel computing that has multiprocessor and multithreading now; Analyze under the very many situation of this uncertain parameter at power system transient stability; Accelerate simulation velocity; And in the realization of energy function appraisal procedure, taken into full account the relation of computational speed, result of calculation accuracy, memory requirements and four aspects of programming realization difficulty, the accuracy of result of calculation should be fully guaranteed.

(5) satisfied demand, improved the fail safe of analysis efficiency and electric power system the power system information real-time.

Description of drawings

Fig. 1 is the transient stability security evaluation flow chart based on risk provided by the invention;

Fig. 2 is provided by the invention based on Monte-Carlo sampling formation fault sampled sequence flow chart;

Fig. 3 a is the interpolation method sketch map that calculates cutter controlled quentity controlled variable principle based on the energy function method provided by the invention;

Fig. 3 b is the extrapolation sketch map that calculates cutter controlled quentity controlled variable principle based on the energy function method provided by the invention;

Fig. 4 is the sketch map of the transient stability analytical method based on energy function provided by the invention;

Fig. 5 is the sketch map of the calculating of stable trajectory nargin provided by the invention;

The sketch map of the Task Distribution topological structure that Fig. 6 combines with the transient energy function method for DSMC provided by the invention.

Embodiment

For making the object of the invention, technical scheme and advantage clearer, embodiment of the present invention is done to describe in detail further below in conjunction with accompanying drawing.

In order to satisfy demand to the power system information real-time; Improve the fail safe of analysis efficiency and electric power system; The embodiment of the invention provides a kind of method that improves the power system transient stability analysis efficiency, referring to Fig. 1, Fig. 2, Fig. 3 a, Fig. 3 b, Fig. 4, Fig. 5 and Fig. 6, sees hereinafter for details and describes:

101: the power system component parameter is carried out initialization, the input electric power system data;

Wherein, electric power system data comprises: bus, circuit, generator data and component reliability parameter.

102: network topology state, generator state and load level to electric power system are selected, and confirm operation states of electric power system;

Wherein, the preceding operation states of electric power system of fault is by network topology, generator state and the load level definition of electric power system.The purpose that depends on research, these three factors perhaps can be specified on being determined property ground, perhaps can be extracted randomly.

If search time is longer, it has comprised different operation states of electric power system, and the purpose of research is to analyze the average risk of electric power system in the preset time scope, and POWER SYSTEM STATE should extract according to the probabilistic ground that occurs before the fault.

If search time is shorter, can specify on being determined property ground, power system network topology, generation mode and the load level corresponding with this short time interval can obtain from electric power system EMS (EMS), thereby can specify on being determined property ground.

103: carry out the Monte Carlo sampling through operation states of electric power system and select, form fault sampled sequence X=(x ₁, x ₂..., x _n);

This method has been considered the characteristic of the enchancement factor of the big disturbance fault of electric power system, and this step is specially:

1) using the Monte Carlo samples to fault element, fault type and fault clearing time;

Wherein, when fault element is circuit, also need sample to abort situation.

2) obtain k (the inferior electric power system fault sample mode x of 1≤k≤n) _k

3) failure judgement sample mode x _kWhether be included among the existing fault sampled sequence X, if, to the k time electric power system fault sample mode x _kAgain the selection of sampling; If not, add among the fault sampled sequence X, and make k=k+1;

4) judge whether k equals n, if, execution in step 104; If not, execution in step 1).

Wherein, the sampling simulation times set for satisfying the Monte Carlo sampling precision of n.Fault element, fault type and fault clearing time sampled can adopt like drag:

(1) probabilistic model of fault element

The embodiment of the invention has only been considered the main random factor to the bigger element of transient stability influence, for example: circuit and transformer.Below with circuit B _iProbability P r (the B that breaks down for example explanation _i):

$\mathrm{Pr}\left(B_i\right)=\mathrm{Pr}(N=1|{\mathrm{\&lambda;}}_i)=\frac{e^{-\mathrm{\&lambda;}}{{\mathrm{\&lambda;}}_i}^N}{N!}={\mathrm{\&lambda;}}_i{e}^{-{\mathrm{\&lambda;}}_i}(i=\mathrm{1,2},...,n_l)---\left(1\right)$

λ in the formula _iRepresent (for example 1 year) interior circuit B of observed time _iFailure-frequency; n _lBe circuit sum in the electric power system.On the basis of supposition power system component state (operation states of electric power system and fault sample mode) duration obeys index distribution; Adopt inverse transformation method to simulate each element state duration of electric power system, thereby obtain operation states of electric power system and state duration.

(2) probabilistic model of fault type

The probability that dissimilar faults takes place is relevant with line voltage distribution grade, network configuration and weather conditions.To certain bar specific circuit, type is C _iThe frequency that takes place of fault be f _i, probability of happening Pr (C then _i) be:

$\mathrm{Pr}\left(C_i\right)=\frac{f_i}{\underset{i=1}{\overset{n_t}{\mathrm{\&Sigma;}}}{f}_i}(i=1,...,n_t)---\left(2\right)$

N in the formula _tExpression fault type sum, and have,

$\underset{i=1}{\overset{n_t}{\mathrm{\&Sigma;}}}\mathrm{Pr}\left(C_i\right)=1---\left(3\right)$

(3) probabilistic model of abort situation

Be primarily aimed at line fault, the abort situation on circuit is generally disobeyed even distribution, can use based on the discrete probability distribution of historical statistics and simulate.Article one, circuit is divided into the M section.Fault occurs in the probability P r (D of i section _i) do

$\mathrm{Pr}\left(D_i\right)=\frac{f_i}{\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{f}_i}(i=1,...,M)---\left(4\right)$

F in the formula _iIt is the number of faults that in historical data, occurs in the i section.

(4) probabilistic model of fault clearing time

Describe fault clearing time at random, can adopt formula:

t _cl=xσ+u (5）

μ and σ are respectively the desired value and the standard variance of the normal distribution of fault clearing time stochastic variable in the formula.

104: adopt method for allocating tasks, to fault sampled sequence X=(x towards the parallel multiprocessor system ₁, x ₂..., x _n) distribute;

Wherein, this step specifically comprises:

Primary processor is with fault sampled sequence X=(x when 1) initial ₁, x ₂..., x _n) uniform distribution gives respectively from processor;

2) when primary processor receive calculate end signal and assessment result from processor after, to fault sampling of current processor reallocation, and send the continuation fill order.

105: each is sampled to fault based on energy function from processor and carries out the transient stability analysis;

As the reference point of calculating potential energy, the kinetic energy of the transient state energy of definable electric power system and potential energy are used following formulate respectively with the origin of coordinates:

$\mathrm{NKE}=\frac{1}{2}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{\widetilde{\mathrm{\&omega;}}}_i^2=\frac{1}{2}{\widetilde{\mathrm{\&omega;}}}^T\widetilde{\mathrm{\&omega;}}=\frac{1}{2}{\left|\widetilde{\mathrm{\&omega;}}\right|}^2---\left(6\right)$

$\mathrm{NPE}=-\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}\underset{0}{\overset{{\mathrm{\&theta;}}_i}{\&Integral;}}{a}_{i}d{\mathrm{\&theta;}}_i---\left(7\right)$

Wherein m is the generator number of participating in operation in the system; θ _iWith

Be respectively angle and the angular speed of generator with respect to the center of inertia, and δ _i(rad) and ω _i(rad/s) represent angle and the angular speed of generator amature respectively with respect to synchronous rotating shaft; M _i(s ²/ rad) expression generator inertia time constant, and

${\mathrm{\&theta;}}_i={\mathrm{\&delta;}}_i-\frac{1}{M_T}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{M}_i{\mathrm{\&delta;}}_i$ ,i=1,2,…,n （8）

${\widetilde{\mathrm{\&omega;}}}_i={\stackrel{\&CenterDot;}{\mathrm{\&delta;}}}_i-\frac{1}{M_T}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{M}_i{\mathrm{\&omega;}}_i$

Can get by the energy function relation

$\mathrm{NEF}\&equiv;\mathrm{NKE}+\mathrm{NPE}\&equiv;\frac{1}{2}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{\widetilde{\mathrm{\&omega;}}}_i^2+\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}\underset{0}{\overset{{\mathrm{\&theta;}}_i}{\&Integral;}}-a_{i}d{\mathrm{\&theta;}}_i---\left(9\right)$

Wherein, this step specifically comprises:

1) current system running state being carried out trend calculates; Judge whether and to cross the border because of element fault causes the operation constraint; Comprise that generator reactive crosses the border, busbar voltage is crossed the border, circuit overload or trend do not restrain; If, adjustment generator output or change of load level, and carry out the adjusted trend of running status again and calculate; If not, execution in step 2);

Wherein, the embodiment of the invention adopts the BPA business software to carry out electric power system tide and calculates and step 2) stability analysis, when specifically realizing, can also adopt other business software to calculate, this does not limit the embodiment of the invention again.

The energy margin computational methods of tradition stable trajectory ^[2-3]Be the sustained fault track that adds again along at the P point, calculating P point to this track is the transient state energy nargin under the stable case at the potential energy increment of the effusion point B on the NPEBS.It is complicated that but this method realizes in the Computer Simulation of large-scale electrical power system, consuming time longer because be difficult in advance know when this track has passed through its backswing point and need restart emulation when carrying out electric system simulation, and analysis efficiency is low ^[4-5]For fear of pseudo-fault track emulation, adopt angle mould plate technique calculation stability track t in the embodiment of the invention _R2Energy margin.This technology is at first along unstable track t _R1The P ' such as potential energy point such as grade of P is put in the search of march line integral.Suppose that the potential energy interface is smooth, can be similar to by P ' on the unstable track of expression to e according to the potential energy increment of P to B on the conservation of energy principle stable trajectory ₁The kinetic energy decrement represent:

$\mathrm{NEM}=\underset{i=1}{\overset{\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="HDA00001824835200052.png"\; state="\{\{state\}\}">m</figure-callout>}}{\mathrm{\&Sigma;}}}\frac{1}{2}{\widetilde{\mathrm{\&omega;}}}_i^2\left(P^{\&prime;}\right)-\underset{i=1}{\overset{\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="HDA00001824835200052.png"\; state="\{\{state\}\}">m</figure-callout>}}{\mathrm{\&Sigma;}}}\frac{1}{2}{\widetilde{\mathrm{\&omega;}}}_i^2\left(e_1\right)---\left(10\right)$

In the formula

Be the angular speed of generator with respect to the center of inertia,

δ _i(rad) and ω _i(rad/s) represent angle and the angular speed of generator amature with respect to synchronous rotating shaft, the angular speed δ of generator respectively _i(rad) be the data of transient stability emulation pilot process, obtain easily in the analysis software;

And M _i(s ²/ rad) be the inertia time constant of generator, be the input parameter of system element.

Because the curvilinear integral starting point is a stable equilibrium point after the fault, and integration is relevant with the path, bring certain difficulty thereby give to calculate.In order to remedy above-mentioned deficiency, the embodiment of the invention adopts a kind of new method of calculation stability track energy margin on angle template basis.

If t _ClConstantly excise this fault, transient state energy nargin can be by computes:

NEM=NPE(B)-[NPE(t _cl)+NKE(t _cl)] （11）

In the formula: first is transition energy, representes with an energy at B place; Second portion is the energy on the track after the fault; Because the normalized energy of whole system is a conservation after the fault; So the normalized energy at some P place can replace with fault clearance energy constantly; Be an A place normalization potential energy and normalization kinetic energy sum, wherein kinetic energy only comprises the live part that contributes to system's unstability.Formula (11) is equivalent to:

NEM=ΔNPE(t _cl)-NKE(t _cl) （12）

NKE (t wherein _Cl) can obtain by formula (6), and Δ NPE (t _Cl) be illustrated in t _ClConstantly excise electric power system after the fault and absorb the ability of effective NKE, promptly among Fig. 5 by t _R2Fault clearance moment point A passes through the potential energy increment of the spill point B of NPEBS to pseudo-fault track.The result of calculation of practical power systems shows, is more or less the same if stablize with the jitterbug track mute time, then at R ⁿIn the angular region, e during jitterbug track ride through system potential energy interface ₁The potential energy that B was ordered when the potential energy of point and pseudo-fault track passed through the potential energy interface is close, and promptly the potential energy interface is smooth near the B point, therefore can suppose NPE (B)=NPE (e ₁).Can use on the sustained fault track point A to potential energy increment and the unstable track t of some C according to the conservativeness point A of track energy after the NEF fault to the potential energy increment of putting B _R1Last some C is to putting e ₁The kinetic energy decrement add up to come approximate.So, Δ NPE (t in the formula (12) _Cl) can obtain by computes:

$\mathrm{\&Delta;NPE}\left(t_{\mathrm{cl}}\right)=-\frac{1}{2}\underset{j=1}{\overset{T-1}{\mathrm{\&Sigma;}}}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}\left\{\right[{\mathrm{\&theta;}}_i\left(t_{j+1}\right)-{\mathrm{\&theta;}}_i\left(t_j\right)]\&times;[a_i\left(\mathrm{\&theta;}\left(t_{j+1}\right)\right)+a_i\left(\mathrm{\&theta;}\left(t_j\right)\right)\left]\right\}---\left(13\right)$

In the formula: first is that the malfunction of trying to achieve with trapezoid formula is by t _ClTo t _Cl+ Δ t normalization potential energy increment constantly, wherein T is from t _ClTo t _ClThe transient stability analysis emulation step number of+Δ t; θ _i(t _j) expression with the transient stability simulation process in t _jCorresponding constantly i platform generator's power and angle; a _i(θ (t _j)) angular acceleration of the i platform generator that obtains by system-computed after the fault.

Above-mentioned information is analyzed the process variable that mediates in the business simulation software at the BPA power system stability, obtains easily, when specifically realizing, can also adopt other business software to calculate, and this does not limit the embodiment of the invention again.

2) operation states of electric power system is carried out stability analysis, with fault sample mode x _kCarry out emulation for disturbance, judge whether electric power system is stable, if, then being designated as type one, implication is fault sample mode x _kFollowing power system stability, and change step 5); If, do not calculate the transient state energy nargin NEM (P of electric power system ₀), execution in step 3);

$\mathrm{NEM}\left(P\right)=\frac{1}{2}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{\widetilde{\mathrm{\&omega;}}}_i^2-\frac{1}{2}\underset{j=1}{\overset{T-1}{\mathrm{\&Sigma;}}}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}\left\{\right[{\mathrm{\&theta;}}_i\left(t_{j+1}\right)-{\mathrm{\&theta;}}_i\left(t_j\right)]\&times;[a_i\left(\mathrm{\&theta;}\left(t_{j+1}\right)\right)+a_i\left(\mathrm{\&theta;}\left(t_j\right)\right)\left]\right\}---\left(14\right)$

T is from t _ClTo t _ClThe transient stability analysis emulation step number of+Δ t; θ _i(t _j) expression take after the P stabilizing measures controlled quentity controlled variable with the transient stability simulation process in t _jCorresponding constantly i platform generator's power and angle; a _i(θ (t _j)) expression t _jThe angular acceleration of moment i platform generator; a _i(θ (t _J+1)) expression t _J+1The angular acceleration of moment i platform generator.

3) from preset stabilizing measures, select fault sample mode x _kStabilizing measures scheme P ₁, carry out stability analysis emulation, and calculate the transient state energy nargin NEM (P of electric power system ₁);

Wherein, preset stabilizing measures is set based on the needs in the practical application, and when specifically realizing, the embodiment of the invention does not limit this.The concrete computational process of this step is referring to step 2), the embodiment of the invention is not done at this and is given unnecessary details.

4) based on total injecting power balance principle, through energy function method calculation stability measure controlled quentity controlled variable.

Wherein, this step specifically comprises:

4a) according to transient state energy nargin NEM (P ₀) and NEM (P ₁), adopt interpolation method of energy margin to ask for best cutter capacity P _{2, gen}

Wherein, best cutter capacity is by computes:

${\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA00001824835200051.png"\; state="\{\{state\}\}">P</figure-callout>}}_{2,\mathrm{gen}}=0.5[{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA00001824835200052.png"\; state="\{\{state\}\}">P</figure-callout>}}_1+\frac{-\mathrm{NEM}\left(P_1\right)(P_0-P_1)}{\mathrm{NEM}\left(P_0\right)-\mathrm{NEM}\left(P_1\right)}]---\left(15\right)$

Wherein, P ₀Stabilizing measures, i.e. P are not adopted in expression ₀Equal 0.

4b) based on total injecting power balance principle, according to best cutter capacity P _{2, gen}, calculation stability measure scheme P ₂In corresponding cutting load amount P _{2, load}=P _{2, gen}

4c) based on the maximum stabilizing measures controlled quentity controlled variable P that allows of fault under preset stabilizing measures and the current state _Max, judge whether P _{2, gen}+ P _{2, load}>=P _Max, if then get P _{2, gen}=P _{2, load}=0.5P _MaxIf not, do not adjust;

Wherein the fault maximum allows stabilizing measures amount P under the current state _MaxGood by power system operation department advance planning, also can decide by the maximum cutter amount that current system allows, the embodiment of the invention does not limit this when specifically realizing.

4d) according to the stabilizing measures scheme P that obtains ₂, electric power system is contained the stability simulation that the cutter cutting load is operated, judge whether electric power system is stable, if, being designated as type two, implication is that electric power system is in controlled instability status; If not, be designated as type three, implication is that uncontrollable unstability takes place in electric power system;

5) with fault sample mode x _kSend to primary processor with the transient stability types results.

If wherein type two or three also need comprise the stabilizing measures amount of being taked.For improving the intuitive of analysis result; And then provide support for the risk assessment of whole electric power system; Can this transient stability analysis result further be formed the risk quantification index; This index may be defined as: the transient stability risk loss quantizating index of type one is zero, and the transient stability risk loss quantizating index of type two is a stabilizing measures amount of avoiding the transient state unstability to take.The loss of outage of transient stability risk loss quantizating index for causing of type three owing to system's unstability.Stability analysis result and transient stability risk thereof through each fault that obtains in this transient stability analysis implementation process is sampled are lost quantizating index; Can ask for the economic loss risk under the current running status of electric power system, and can walk crosswise comparison the different electric power running status.

Step 105 is the transient stability analysis processes based on energy function of carrying out from processor single, can calculate through multiprocessor (or many kernels) is parallel.For fully excavating existing PC multiprocessor (kernel) and multithreading, developed the Task Distribution topological structure that Monte-Carlo state sampling method combines with the transient energy function convergence criterion, as shown in Figure 6: at initial work I ₀After the completion, primary processor gives the Monte-Carlo simulation Task Distribution of n state respectively from processor, and these tasks are represented as T ₁, T ₂T _P-1After respectively receiving an assignment, at first obtain n system mode, then each similar malfunction is accomplished network analysis, then form the stability indicator under n the system mode based on the transient energy function method through the Monte-Carlo simulation from processor.After accomplishing the simulation task, primary processor is passed to the result from processor immediately, and proceeds the Monte-Carlo simulation task of next n state.Refresh reliability index immediately and restrain control C behind the result that primary processor (kernel) obtains respectively passing back from processor (kernel) ₀, do not reach precision as if thinking, then continue to wait for and pass new result back from processor, restrain as if thinking, send the order S that stops to simulate then for from processor all ₀Primary processor is carried out F ₀Accomplish the index of this transient stability analysis and export final result.

106: primary processor receives the result who passes back from processor to respectively, and the result is saved in database.

107: whether failure judgement sampled sequence X accomplishes, if, execution in step 108; If not, execution in step 104;

108: calculate the probability level of electric power system transient stability, and the output result.

Realized the power system transient stability rapid analysis under the uncertain condition through above-mentioned steps; Improved the efficient of power system transient stability assessment greatly, this method is that the transient stability analytical applications under the uncertain condition creates conditions to analysis of electric power system safety on line and warning aspect.

In sum; The embodiment of the invention provides a kind of method that improves the power system transient stability analysis efficiency; This method adopts the energy function method based on the angle mould plate technique; Avoid the lasting track integral process of pseudo-fault of hybrid algorithm in the past, greatly accelerated the estimating velocity of transient stability, and maintenance level that provides each sample states transient stability and margin of safety that can be quantitative; Satisfied demand, improved the fail safe of analysis efficiency and electric power system the power system information real-time.

List of references:

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[2]Fang?D?Z,Chung?T?S,David?A?K.Improved?Techniques?for?Hybrid?Method?in?Fast?Transient?Stability?Assessment?[J],IEE?Proceedings-Generation,Transmission?and?Distribution,1998,144(2):107-112.

[3]Tang?C?K,Graham?C?E,El-Kady?M,et?al.Transient?Stability?Index?from?Conventional?Time?Domain?Simulation[J].IEEE?Transactions?on?Power?Systems,1994,9(3):1524-1530.

[4]Fang?D?Z,Chung?T?S,Zhang?Y,et?al.Transient?Stability?Limit?Conditions?Analysis?Using?a?Corrected?Transient?Energy?Function?Approach?[J].IEEE?Transaction?on?Power?systems,200015(2):804-810.

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It will be appreciated by those skilled in the art that accompanying drawing is the sketch map of a preferred embodiment, the invention described above embodiment sequence number is not represented the quality of embodiment just to description.

The above is merely preferred embodiment of the present invention, and is in order to restriction the present invention, not all within spirit of the present invention and principle, any modification of being done, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (5)

1. a method that improves the power system transient stability analysis efficiency is characterized in that, said method comprising the steps of:

(1) the power system component parameter is carried out initialization, the input electric power system data;

(2) network topology state, generator state and the load level of electric power system are selected, confirmed operation states of electric power system;

(3) carry out the Monte Carlo sampling through said operation states of electric power system and select, form fault sampled sequence X=(x ₁, x ₂..., x _n);

(4) employing is towards the method for allocating tasks of parallel multiprocessor system, to said fault sampled sequence X=(x ₁, x ₂..., x _n) distribute;

(5) each is sampled to fault based on energy function from processor and carries out the transient stability analysis;

(6) primary processor receives to each said result who passes back from processor, and the result is saved in database;

(7) judge whether said fault sampled sequence X accomplishes, if, execution in step (8); If not, execution in step (4);

(8) calculate the probability level of electric power system transient stability, and export the result.

2. a kind of method that improves the power system transient stability analysis efficiency according to claim 1 is characterized in that, saidly carries out Monte Carlo sampling through said operation states of electric power system and selects, and forms fault sampled sequence X=(x ₁, x ₂..., x _n) specifically comprise:

1) using the Monte Carlo samples to fault element, fault type and fault clearing time;

2) obtain the fault sample mode x of the k time electric power system _k, 1≤k≤n;

3) judge said fault sample mode x _kWhether be included among the existing said fault sampled sequence X, if, to said fault sample mode x _kAgain the selection of sampling; If, do not add among the said fault sampled sequence X, and make k=k+1;

4) judge whether k equals n, if, execution in step (4); If not, execution in step 1), wherein, n representes the simulation times of sampling.

3. a kind of method that improves the power system transient stability analysis efficiency according to claim 2 is characterized in that, said each based on energy function the transient stability analysis is carried out in fault sampling from processor and is specifically comprised:

1) current system running state being carried out trend calculates; Judge whether and to cross the border because of element fault causes the operation constraint; Comprise that generator reactive crosses the border, busbar voltage is crossed the border, circuit overload or trend do not restrain; If, adjustment generator output or change of load level, and carry out the adjusted trend of running status again and calculate; If not, execution in step 2);

2) said operation states of electric power system is carried out stability analysis, with said fault sample mode x _kCarry out emulation for disturbance, judge whether electric power system is stable, if, then being designated as type one, implication is said fault sample mode x _kFollowing power system stability, and change step 5); If, do not calculate the transient state energy nargin NEM (P of electric power system ₀), execution in step 3);

3) from preset stabilizing measures, select said fault sample mode x _kStabilizing measures scheme P ₁, carry out stability analysis emulation, and calculate the transient state energy nargin NEM (P of electric power system ₁);

4) based on total injecting power balance principle, through energy function method calculation stability measure controlled quentity controlled variable;

5) with said fault sample mode x _kSend to said primary processor with the transient stability types results.

4. a kind of method that improves the power system transient stability analysis efficiency according to claim 3 is characterized in that, said transient state energy nargin NEM (P) is specially:

$\mathrm{NEM}\left(P\right)=\frac{1}{2}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{\widetilde{\mathrm{\&omega;}}}_i^2-\frac{1}{2}\underset{j=1}{\overset{T-1}{\mathrm{\&Sigma;}}}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}\left\{\right[{\mathrm{\&theta;}}_i\left(t_{j+1}\right)-{\mathrm{\&theta;}}_i\left(t_j\right)]\&times;[a_i\left(\mathrm{\&theta;}\left(t_{j+1}\right)\right)+a_i\left(\mathrm{\&theta;}\left(t_j\right)\right)\left]\right\}$

M is the generator number of participating in operation in the system;

For taking under the P stabilizing measures controlled quentity controlled variable situation i platform generator with respect to the angular speed in the center of inertia; T constantly takes place from fault in T _ClTo failure removal moment t _ClThe transient stability analysis emulation step number of+Δ t; θ _i(t _j) expression with the transient stability simulation process in t _jCorresponding constantly i platform generator's power and angle; θ _i(t _J+1) expression with the transient stability simulation process in t _J+1Corresponding constantly i platform generator's power and angle; a _i(θ (t _j)) expression t _jThe angular acceleration of moment i platform generator; a _i(θ (t _J+1)) expression t _J+1The angular acceleration of moment i platform generator.

5. a kind of method that improves the power system transient stability analysis efficiency according to claim 4 is characterized in that, and is said based on total injecting power balance principle, through energy function method calculation stability measure controlled quentity controlled variable, specifically comprises:

4a) according to said transient state energy nargin NEM (P ₀) and NEM (P ₁), adopt interpolation method of energy margin to ask for best cutter capacity P _{2, gen}

Wherein, $P_{2,\mathrm{Gen}}=0.5[P_1+\frac{-\mathrm{NEM}\left(P_1\right)(P_0-P_1)}{\mathrm{NEM}\left(P_0\right)-\mathrm{NEM}\left(P_1\right)}]$

P ₀Stabilizing measures is not adopted in expression;

4b) based on total injecting power balance principle, according to said best cutter capacity P _{2, gen}, calculation stability measure scheme P ₂In corresponding cutting load amount P _{2, load}=P _{2, gen}

4c) based on the maximum stabilizing measures amount P that allows of fault under said preset stabilizing measures and the current state _Max, judge whether P _{2, gen}+ P _{2, load}>=P _Max, if then get P _{2, gen}=P _{2, load}=0.5P _MaxIf not, do not adjust;

4d) according to the said stabilizing measures scheme P that obtains ₂, electric power system is contained the stability simulation that the cutter cutting load is operated, judge whether electric power system is stable, if, being designated as type two, implication is that electric power system is in controlled instability status; If not, be designated as type three, implication is that uncontrollable unstability takes place in electric power system.

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