CN103606922A - Approximate judgment method for power angle stability of electric power system based on typical fault set - Google Patents

Abstract

The invention relates to an approximate judgment method for the power angle stability of an electric power system based on a typical fault set. The approximate judgment method comprises the following steps: (1) scanning the typical fault set of the electric power system and obtaining typical operation manner parameters M, Pm, PC0, PCD, PCP, Pmax0, PmaxD, PmaxP, gamma0, gamma D, gamma P, delta0 and PF, and relative data delta cr and tcr of critical stable conditions by utilizing an EEAC (Extend Equal Area Criterion) method; (2) sampling to obtain a fault state and carrying out fault matching; (3) recording power P'F before a fault line has faults and fault actual cutting time tc; (4) sampling to obtain a rotational inertia sum M'S of an acceleration set; (5) sampling to obtain a rotational inertia sum M'A of a deceleration set; (6) calculating an equivalent rotational inertia M'; (7) calculating equivalent ultimate cutting time t'cr; (8) calculating an equivalent mechanical power difference delta Pm before the line has the faults; (9) calculating a difference delta tc between fault actual cutting time and ultimate cutting time of the electric power system; (10) calculating the change delta Aa of an accelerating area; (11) calculating the change delta Ad of a deceleration area; (12) judging whether transient stability exists or not after the line has the faults. The approximate judgment method can be widely applied to risk assessment of the stability of the electric power system.

Description

A kind of Power system stability based on typical fault set is similar to decision method

Technical field

The present invention relates to a kind of power system analysis method, particularly about the approximate decision method of a kind of Power system stability based on typical fault set.

Background technology

Stability of power system refers to that electric power system can operate in generation load poised state under normal operation, can return to the poised state that can allow after being disturbed.Electric power system keeps stable ability to keep safe and reliable power supply significant for electric power system, so the stability analysis of electric power system becomes one of important content of power system analysis.Stability of power system can be divided into angle stability and voltage stability, and wherein angle stability is divided into static angle stability (being called not only " microvariations are stable ") and transient rotor angle stability (but also be called " large disturbance is stable ").Transient rotor angle stability refers to that electric power system suffers to keep each synchronous ability in bus merit angle under serious transient state disturbance, and these disturbances may refer to power transmission line short circuit or lose a high-rating generator etc.After disturbance occurs, due to electric parameters generation instantaneous variation in electrical network, each generator is instantaneous may produce the input power of prime mover and the unbalanced situation of the electromagnetic power of output, and then cause the acceleration or deceleration of generator amature, cause the poor increase of rotor angle between different generators, when rotor angle is poor while being increased to a certain degree, may cause the step-out of generator, and then cause electric power system parallel off and cause large area blackout.The object of electrical power system transient angle stability analysis is the destruction that under the following running status of assessment electric power system, whether possible fault can cause electrical power system transient angle stability, and strengthens the Transient angle stability after electric power system fault by adjusting operation states of electric power system or configuring security and stability control measurement.

At present, stability of power system problem is one of problem of studying more thorough and deeply in power system analysis theory and technology, has possessed comparatively complete theoretical foundation and more perfect analytical method.The analytical method of electric power system transient stability mainly contains time-domain-simulation method, energy function method and extended equal area criterion (ExtendedEqual-Area Criterion, EEAC).Time-domain-simulation method is that generators in power systems, transmission line and load are set up to the differential equation and algebraic equation model, the in the situation that of given disturbance, in time domain, carrying out numerical integration solves, obtain the dynamic response after Power System Disturbances, and carry out based on this judgement of stability of power system.The advantage of time-domain-simulation method is to carry out detailed modeling to complicated electric power system, and very large but its shortcoming is amount of calculation, computational process is very complicated.Energy function method is called again direct method, its basic ideas are according to Liapunov(Liapunov) stability of the character judgement electric power system of function or transient energy function, its advantage is can Quick stability of power system, but has under detailed system model energy function structure difficulty and obtain the too conservative problem of result.Extended equal area criterion is extended to multimachine system by the infinitely great homalographic criterion of unit, set up the concept of accelerating a group of planes and deceleration cluster after fault, the running orbit of multimachine system is mapped as to the two machine groups equivalent track at equivalent inertia center separately, adopts with the infinitely great approximate criterion of unit and calculate neutrality condition.But still there is calculation of complex, problem that amount of calculation is larger in the method.

In the analysiss of uncertainty such as Study of Risk Evaluation Analysis for Power System, often need to carry out the merit angle transient stability sex determination of the possible fault of a large amount of electric power systems, the computational speed of electric power system transient stability decision method is had relatively high expectations.After the electric power system fault that in existing method, sampling obtains each time, all carry out a sequential emulation.Although the theory of existing electric power system transient stability and method are comparatively ripe, but still deposit problem both ways: 1) existing decision method Computing Principle is more complicated and computing cost is larger; 2) existing decision method is all judged for electric power system fault under a certain definite state, for judging each time of a large amount of electric power system faults, all need once complete stable judgement to calculate, therefore when judging a large amount of electric power system fault state, computing time is very long, is difficult to meet the requirement that practical power systems is analyzed.

In Study of Risk Evaluation Analysis for Power System, operation states of electric power system corresponding to the line fault that obtains of sampling is all not identical each time, but for same line fault, in each sampling, operation states of electric power system but has certain similitude, if can, according to electrical power system transient angle stability under all the other atypical states of the approximate judgement of the neutrality condition of electric power system merit angle transient stability under typical operation states of electric power system, can greatly improve computational efficiency.Therefore, be necessary to provide a kind of electrical power system transient angle stability method for rapidly judging, applicable a large amount of electric power system fault state rapid batch is judged, to realize the panorama probabilistic assessment that Transient Security for Power Systems is stable.

Summary of the invention

For the problems referred to above, the object of this invention is to provide the approximate decision method of a kind of Power system stability based on typical fault set.

For achieving the above object, the present invention takes following technical scheme: a kind of Power system stability based on typical fault set is similar to decision method, and it comprises the following steps:

1) scanning electric power system typical fault set, obtains electric power system typical fault set and comprises n typical fault, utilizes EEAC method to obtain electric power system typical operation modes parameter M, the P of all typical faults _m, P _c0, P _cD, P _cP, P _max0, P _maxD, P _maxP, γ ₀, γ _d, γ _p, δ ₀and P _f, and the related data δ of electric power system fault neutrality condition _crand t _cr; Wherein: M is the system equivalent moment of inertia being equivalent to after one machine infinity bus system; P _mfor being equivalent to the equivalent mechanical power after one machine infinity bus system; P _c0for equivalent load angle characteristic initial power before fault; P _cDfor equivalent load angle characteristic initial power in fault; P _cPfor equivalent load angle characteristic initial power after fault; P _max0for equivalent load angle characteristic power magnitude before fault; P _maxDfor equivalent load angle characteristic power magnitude in fault; P _maxPfor equivalent load angle characteristic power magnitude after fault; γ ₀for equivalent load angle characteristic initial phase before fault; γ _dfor equivalent load angle characteristic initial phase in fault; γ _pfor equivalent load angle characteristic initial phase after fault; δ ₀for being equivalent to after one machine infinity bus system the merit angle balance point of equivalence before the system failure; P _ffor power before faulty line fault; δ _crfor being equivalent to critical clearing angle corresponding to system equivalence rotor angle after one machine infinity bus system; t _crfor being equivalent to critical clearing angle corresponding to system equivalence rotor angle after one machine infinity bus system;

2) sampling obtains above-mentioned electric power system fault state, and concentrates typical fault to carry out respectively Trouble Match with above-mentioned electric power system typical fault; If the electric power system fault circuit that sampling obtains is consistent with the faulty line of typical fault, and both fault types are corresponding consistent, think that Trouble Match is successful, on the contrary Trouble Match failure; If the malfunction that obtains of sampling is with the concentrated whole typical fault of typical fault, all the match is successful, thinks after the system failure that this sampling obtains it is transient stability; If the malfunction that obtains of sampling is concentrated any one typical fault with typical fault, the match is successful, enters next step, and whether continuation judges after electric power system fault transient stability;

3) power P before the electric power system fault line fault that record sampling obtains ' _fthe actual mute time t of electric power system fault obtaining with sampling _c;

4) in the electric power system fault state that the acceleration unit in the typical fault that the electric power system fault state that sampling obtains successfully mates obtains in sampling, do not shut down the acceleration unit of the electric power system fault state that being samples obtains; The moment of inertia summation of accelerating unit in the electric power system fault state that sampling obtains is M ' _s;

5) in the electric power system fault state that the deceleration unit in the typical fault that the electric power system fault state that sampling obtains successfully mates obtains in sampling, do not shut down the deceleration unit of the electric power system fault state that being samples obtains; The moment of inertia summation of unit of slowing down in the electric power system fault state that obtains of sampling is M ' _a;

6) press formula M '=M ' _sm ' _a/ (M ' _s+ M ' _a) calculate electric power system equivalent moment of inertia M corresponding to malfunction that electric power system sampling obtains ^';

7) press formula calculate equivalent critical clearing time t ' _cr;

8) press formula Δ P _m=P ' _f-P _fcalculate the difference Δ P of the front equivalent mechanical power of line fault _m;

9) press formula Δ t _c=t _c-t ' _crcalculate the actual mute time t of electric power system fault that sampling obtains _cwith critical clearing time t ' _crdifference Δ t _c;

10) be calculated as follows the changes delta A that accelerates area _a:

$\begin{array}{c}\mathrm{\Δ}{A}_a=\left\{\begin{array}{c}\frac{1}{2M}[P_m-P_{\mathrm{CD}}+P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_D)]\\ \·[2P_m-2P_{\mathrm{CD}}-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_D)-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_P)]t_{\mathrm{cr}}^{\′}\end{array}\right\}\mathrm{\Δ}{t}_c\\ +\left\{\begin{array}{c}({\mathrm{\δ}}_{\mathrm{cr}}-{\sin }^{-1}\frac{P_m-P_{C0}}{P_{\max 0}}+{\mathrm{\γ}}_0)-\frac{P_m-P_{\mathrm{CD}}}{P_{\max 0}\sqrt{1-{[(P_m-P_{C0})/P_{\max 0}]}^2}}\\ +\frac{P_{\max D}\sin \left({\sin }^{-1}\right[(P_m-P_{C0})/P_{\max 0}]+{\mathrm{\γ}}_0-{\mathrm{\γ}}_D)}{P_{\max 0}\sqrt{1-{[(P_m-P_{C0})/P_{\max 0}]}^2}}\end{array}\right\}\mathrm{\Δ}{P}_m\end{array};$

11) be calculated as follows the changes delta A of retardation area _d:

$\begin{array}{c}{\mathrm{\ΔA}}_d=\left\{\begin{array}{c}\frac{1}{2M}[P_{\mathrm{CP}}-P_m+P_{\max P}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_P)]\\ \·[P_m-{2P}_{\mathrm{CD}}-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_D)-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_P)]t_{\mathrm{cr}}^{\′}\end{array}\right\}{\mathrm{\Δt}}_c;\\ +[{\mathrm{\δ}}_{\mathrm{cr}}+{\sin }^{-1}\frac{P_m-P_{\mathrm{CP}}}{P_{\max P}}-{\mathrm{\γ}}_P-\mathrm{\π}]{\mathrm{\ΔP}}_m\end{array}$

12) the area variation relative with retardation area accelerated in judgement: if Δ A _a-Δ A _d> 0, can think after electric power system fault and will produce Transient Instability; If Δ A _a-Δ A _d≤ 0, can think after electric power system fault it is transient stability.

The present invention is owing to taking above technical scheme, it has the following advantages: the present invention under the definite electric power system typicalness of time-domain-simulation after line fault on the basis of the typical fault set of system neutrality, considers the electric power system typical operation modes parameter of all typical faults in EEAC method that sampling obtains: be equivalent to system equivalent moment of inertia M after one machine infinity bus system, be equivalent to the equivalent mechanical power P after one machine infinity bus system _m, equivalent load angle characteristic initial power P before fault _c0, equivalent load angle characteristic initial power P _cD, equivalent load angle characteristic initial power P after fault _cP, equivalent load angle characteristic power magnitude P before fault _max0, equivalent load angle characteristic power magnitude P in fault _maxD, equivalent load angle characteristic power magnitude P after fault _maxP, equivalent load angle characteristic initial phase γ before fault ₀, equivalent load angle characteristic initial phase γ in fault _d, equivalent load angle characteristic initial phase γ after fault _p, be equivalent to after one machine infinity bus system the merit angle balance point δ of equivalence before the system failure ₀, power P before faulty line fault _f, the related data of electric power system fault neutrality condition: be equivalent to critical clearing angle δ corresponding to system equivalence rotor angle after one machine infinity bus system _cr, be equivalent to critical clearing angle t corresponding to system equivalence rotor angle after one machine infinity bus system _crthe difference Δ P of equivalent mechanical power before the line fault obtaining with sampling _m, the actual mute time t of fault _c, critical clearing time t ' _cr, utilize above-mentioned parameter to calculate under atypical state fault phase for the variation delta A of the acceleration energy of fault under typicalness _avariation delta A with deceleration energy _drelative size, judge after electric power system fault whether be transient stability, the present invention takes full advantage of given electric power system neutrality typical fault set, accelerating time and the deceleration time by calculating sampling state, compared with typical fault set save computing time, and then improve the efficiency of stable judgement, impel the validity of the risk assessment of stability of power system to be greatly improved.Therefore, the present invention can be widely used in the risk assessment of stability of power system.

Accompanying drawing explanation

Fig. 1 is IEEE RTS-79 power system network topological diagram in the embodiment of the present invention

Embodiment

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

The present invention includes following steps:

1) first scan electric power system typical fault set, obtain n typical fault of electric power system typical fault set, that is: typical fault 1, typical fault 2, typical fault 3 ..., typical fault n; Then utilize EEAC(Extended Equal-Area Criterion) method obtains the electric power system typical operation modes parameter of all typical faults, that is: M, P _m, P _c0, P _cD, P _cP, P _max0, P _maxD, P _maxP, γ ₀, γ _d, γ _p, δ ₀and P _f, and the related data δ of electric power system fault neutrality condition _crand t _cr.Wherein:

M is the system equivalent moment of inertia being equivalent to after one machine infinity bus system, and unit is Mkgm ²/ s;

P _mfor being equivalent to the equivalent mechanical power after one machine infinity bus system, unit is MW;

P _c0for equivalent load angle characteristic initial power before fault, unit is MW;

P _cDfor equivalent load angle characteristic initial power in fault, unit is MW;

P _cPfor equivalent load angle characteristic initial power after fault, unit is MW;

P _max0for equivalent load angle characteristic power magnitude before fault, unit is MW;

P _maxDfor equivalent load angle characteristic power magnitude in fault, unit is MW;

P _maxPfor equivalent load angle characteristic power magnitude after fault, unit is MW;

γ ₀for equivalent load angle characteristic initial phase before fault, unit is rad;

γ _dfor equivalent load angle characteristic initial phase in fault, unit is rad;

γ _pfor equivalent load angle characteristic initial phase after fault, unit is rad;

δ ₀for being equivalent to after one machine infinity bus system the merit angle balance point of equivalence before the system failure, unit is rad;

P _ffor power before faulty line fault, unit is MW;

δ _crfor being equivalent to critical clearing angle corresponding to system equivalence rotor angle after one machine infinity bus system, unit is rad;

T _crfor being equivalent to critical clearing angle corresponding to system equivalence rotor angle after one machine infinity bus system, unit is s;

2) sampling obtains above-mentioned electric power system fault state, and carries out respectively Trouble Match with concentrated n the typical fault of above-mentioned electric power system typical fault;

If the electric power system fault circuit that sampling obtains is consistent with the faulty line of typical fault, and both fault types are corresponding consistent, think that Trouble Match is successful, on the contrary Trouble Match failure.

If the malfunction that sampling obtains and typical fault are concentrated whole typical faults, all the match is successful, thinks that the electric power system that this sampling obtains is transient stability after fault.

If the malfunction that obtains of sampling is concentrated any one typical fault with typical fault, the match is successful, enters next step, and whether continuation judges after electric power system fault transient stability;

3) power P before the electric power system fault line fault that record sampling obtains ' _fthe actual mute time t of electric power system fault that MW and sampling obtain _cs;

4) in the electric power system fault state that the acceleration unit in the typical fault that the electric power system fault state that sampling obtains successfully mates obtains in sampling, do not shut down the acceleration unit of the electric power system fault state that being samples obtains; The moment of inertia summation of accelerating unit in the electric power system fault state that sampling obtains is M ' _smkgm ²/ s;

5) in the electric power system fault state that the deceleration unit in the typical fault that the electric power system fault state that sampling obtains successfully mates obtains in sampling, do not shut down the deceleration unit of the electric power system fault state that being samples obtains; The moment of inertia summation of unit of slowing down in the electric power system fault state that obtains of sampling is M ' _amkgm ²/ s;

6) press formula M '=M ' _sm ' _a/ (M ' _s+ M ' _a) calculate electric power system equivalent moment of inertia M ' Mkgm corresponding to malfunction that electric power system sampling obtains ²/ s;

7) press formula calculate its equivalent critical clearing time t ' _crs;

8) press formula Δ P _m=P ' _f-P _fcalculate the difference Δ P of the front equivalent mechanical power of line fault _mmW;

9) press formula Δ t _c=t _c-t ' _crcalculate the actual mute time t of electric power system fault that sampling obtains _cs and critical clearing time t ' _crthe difference Δ t of s _cs;

10) be calculated as follows the changes delta A that accelerates area _a:

$\begin{array}{c}\mathrm{\Δ}{A}_a=\left\{\begin{array}{c}\frac{1}{2M}[P_m-P_{\mathrm{CD}}+P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_D)]\\ \·[2P_m-2P_{\mathrm{CD}}-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_D)-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_P)]t_{\mathrm{cr}}^{\′}\end{array}\right\}\mathrm{\Δ}{t}_c\\ +\left\{\begin{array}{c}({\mathrm{\δ}}_{\mathrm{cr}}-{\sin }^{-1}\frac{P_m-P_{C0}}{P_{\max 0}}+{\mathrm{\γ}}_0)-\frac{P_m-P_{\mathrm{CD}}}{P_{\max 0}\sqrt{1-{[(P_m-P_{C0})/P_{\max 0}]}^2}}\\ +\frac{P_{\max D}\sin \left({\sin }^{-1}\right[(P_m-P_{C0})/P_{\max 0}]+{\mathrm{\γ}}_0-{\mathrm{\γ}}_D)}{P_{\max 0}\sqrt{1-{[(P_m-P_{C0})/P_{\max 0}]}^2}}\end{array}\right\}\mathrm{\Δ}{P}_m\end{array};$

From above formula, accelerate the changes delta A of area _aby M, P _m, P _cD, P _maxD, δ _cr, γ _d, γ _p, t ' _cr, Δ t _c, P _c0, P _max0, γ ₀with Δ P _mdetermine.11) be calculated as follows the changes delta A of retardation area _d:

$\begin{array}{c}{\mathrm{\ΔA}}_d=\left\{\begin{array}{c}\frac{1}{2M}[P_{\mathrm{CP}}-P_m+P_{\max P}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_P)]\\ \·[P_m-{2P}_{\mathrm{CD}}-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_D)-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_P)]t_{\mathrm{cr}}^{\′}\end{array}\right\}{\mathrm{\Δt}}_c;\\ +[{\mathrm{\δ}}_{\mathrm{cr}}+{\sin }^{-1}\frac{P_m-P_{\mathrm{CP}}}{P_{\max P}}-{\mathrm{\γ}}_P-\mathrm{\π}]{\mathrm{\ΔP}}_m\end{array}$

From above formula, the changes delta A of retardation area _dby M, P _cP, P _m, P _maxP, δ _cr, γ _p, P _cD, P _maxD, γ _d, t ' _cr, Δ t _cwith Δ P _mdetermine.

12) the area variation relative with retardation area accelerated in judgement, if Δ A _a-Δ A _d> 0, can think after electric power system fault and will produce Transient Instability.If Δ A _a-Δ A _d≤ 0, can think after electric power system fault it is transient stability.

Specific embodiment:

As shown in Figure 1, at IEEE RTS-79(IEEE Reliability Test System-79) in power system network topological diagram,

represent generator, represent load (power consumption equipment),

indication transformer, 138kV and 230kV representative voltage grade.

IEEE RTS-79 electric power system comprises 24 bus Bi altogether, i=1 wherein, and 2 ..., 24; 32 generating set Gi, i=1 wherein, 2 ..., 32; Article 38, branch road Li, i=1 wherein, 2 ..., 38; Maximum load 2850MW, installed capacity is 3405MW.

Region Ri represents that the node at generating set place belongs to certain region, i=1 wherein, and 2 ..., 32; Region R1 comprises Node B 1, B3, B4, B5; Region R2 comprises Node B 2, B6, B7, B8; Region R3 comprises Node B 9, B10, B11, B12; Region R4 comprises Node B 13; Region R5 comprises Node B 19, B20, B23; Region R6 comprises Node B 14, B15, B16, B24; Region R7 comprises Node B 17, B18, B21, B22.Generator 's parameter following (as shown in table 1):

Table 1 generator parameter table

Line parameter circuit value table following (as shown in table 2), wherein Line Flow positive direction is for to flow to circuit terminal node from circuit start node.

Table 2 line parameter circuit value table

1) scanning electric power system typical fault set, utilizes EEAC method to obtain the related data of electric power system typical operation modes parameter and electric power system fault neutrality condition.At this typical fault, concentrate and obtain two typical faults 1,2.Wherein, the circuit that typical fault 1 comprises is L19, and fault type is three-phase shortcircuit, before fault, Line Flow is-150MW, acceleration region comprises R1, R2, R3, R4, and deceleration region comprises R5, R6, R7, electric power system typical operation modes parameter: M=3987.8855Mkg.m ²/ s, P _m=150MW, P _c0=0MW, P _cD=0MW, P _cP=0MW, P _max0=604.0187MW, P _maxD=100MW, P _maxP=400MW, γ ₀=0rad, γ _d=0rad, γ _p=0rad, δ ₀=0.2rad, P _f=150MW, the related data of electric power system fault neutrality condition: δ _cr=1.2rad and t _cr=0.5s.The circuit that typical fault 2 comprises is L21, L22, fault type is three-phase shortcircuit, be respectively-150MW of Line Flow ,-150MW before fault, and acceleration region comprises R1, R2, R3, R4, deceleration region comprises R5, R6, R7, electric power system typical operation modes parameter: M=3987.8855Mkgm ²/ s, P _m=300MW, P _c0=-50MW, P _cD=-60MW, P _cP=-60MW, P _max0=604.0187MW, P _maxD=100MW, P _maxP=400MW, γ ₀=-0.1rad, _{γ D}=-0.09rad, _{γ P}=-0.11rad, δ ₀=0.3267rad, P _f=300MW, the related data of electric power system fault neutrality condition: δ _cr=1.2rad and t _cr=0.5s;

2) sampling obtains electric power system fault state, faulty line is L19, fault type is three-phase shortcircuit, by faulty line, be that the concentrated typical fault set of L19 and electric power system typical fault 1,2 carries out respectively Trouble Match, successfully mated typical fault 1, enter next step, whether continue to judge after electric power system fault transient stability;

3) power P before the electric power system fault circuit L19 fault that record sampling obtains ' _f=-200MW, the actual mute time t of electric power system fault that sampling obtains _c=0.5s;

4) the acceleration unit of the electric power system fault state obtaining for this sampling that G1～G14 unit is not shut down in this sampling; In the electric power system fault state that sampling obtains, accelerate the moment of inertia summation MS '=10650Mkgm of unit ²/ s;

5) the deceleration unit of the electric power system fault state obtaining for this sampling that G15～G32 unit is not shut down in this sampling; The moment of inertia summation M ' of unit slows down in the electric power system fault state that obtains of sampling _a=6275Mkgm ²/ s;

6) press formula M '=M ' _sm ' _a/ (M ' _s+ M ' _a) calculate electric power system equivalent moment of inertia M '=3948.5229Mkgm corresponding to malfunction that electric power system sampling obtains ²/ s;

7) press formula

calculate its equivalent critical clearing time t ' _cr=0.4975s;

8) press formula Δ P _m=P ' _f-P _fcalculate the difference Δ P of the front equivalent mechanical power of line fault L19 fault _m=50MW;

9) press formula Δ t _c=t _c-t ' _crcalculate the actual mute time t of electric power system fault that sampling obtains _cs and critical clearing time t ' _crthe difference Δ t of s _c=0.0025s;

10) be calculated as follows the changes delta A that accelerates area _a=36.7599

11) be calculated as follows the changes delta A of retardation area _d=-77.8559

$\begin{array}{c}{\mathrm{\ΔA}}_d=\left\{\begin{array}{c}\frac{1}{2M}[P_{\mathrm{CP}}-P_m+P_{\max P}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_P)]\\ \·[P_m-{2P}_{\mathrm{CD}}-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_D)-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_P)]t_{\mathrm{cr}}^{\′}\end{array}\right\}{\mathrm{\Δt}}_c;\\ +[{\mathrm{\δ}}_{\mathrm{cr}}+{\sin }^{-1}\frac{P_m-P_{\mathrm{CP}}}{P_{\max P}}-{\mathrm{\γ}}_P-\mathrm{\π}]{\mathrm{\ΔP}}_m\end{array}$

12) due to Δ A _a-Δ A _d> 0, therefore be transient stability after the electric power system fault that judgement sampling obtains.

The various embodiments described above are only for illustrating the present invention; wherein the structure of each parts, connected mode and manufacture craft etc. all can change to some extent; every equivalents of carrying out on the basis of technical solution of the present invention and improvement, all should not get rid of outside protection scope of the present invention.

Claims (1)

1. the Power system stability based on typical fault set is similar to a decision method, and it comprises the following steps:

1) scanning electric power system typical fault set, obtains electric power system typical fault set and comprises n typical fault, utilizes EEAC method to obtain electric power system typical operation modes parameter M, the P of all typical faults _m, P _c0, P _cD, P _cP, P _max0, P _maxD, P _maxP, γ ₀, γ _d, γ _p, δ ₀and P _f, and the related data δ of electric power system fault neutrality condition _crand t _cr; Wherein:

M is the system equivalent moment of inertia being equivalent to after one machine infinity bus system;

P _mfor being equivalent to the equivalent mechanical power after one machine infinity bus system;

P _c0for equivalent load angle characteristic initial power before fault;

P _cDfor equivalent load angle characteristic initial power in fault;

P _cPfor equivalent load angle characteristic initial power after fault;

P _max0for equivalent load angle characteristic power magnitude before fault;

P _maxDfor equivalent load angle characteristic power magnitude in fault;

P _maxPfor equivalent load angle characteristic power magnitude after fault;

γ ₀for equivalent load angle characteristic initial phase before fault;

γ _dfor equivalent load angle characteristic initial phase in fault;

γ _pfor equivalent load angle characteristic initial phase after fault;

δ ₀for being equivalent to after one machine infinity bus system the merit angle balance point of equivalence before the system failure;

P _ffor power before faulty line fault;

δ _crfor being equivalent to critical clearing angle corresponding to system equivalence rotor angle after one machine infinity bus system;

T _crfor being equivalent to critical clearing angle corresponding to system equivalence rotor angle after one machine infinity bus system;

2) sampling obtains above-mentioned electric power system fault state, and concentrates typical fault to carry out respectively Trouble Match with above-mentioned electric power system typical fault;

If the electric power system fault circuit that sampling obtains is consistent with the faulty line of typical fault, and both fault types are corresponding consistent, think that Trouble Match is successful, on the contrary Trouble Match failure;

If the malfunction that obtains of sampling is with the concentrated whole typical fault of typical fault, all the match is successful, thinks after the system failure that this sampling obtains it is transient stability;

If the malfunction that obtains of sampling is concentrated any one typical fault with typical fault, the match is successful, enters next step, and whether continuation judges after electric power system fault transient stability;

3) power P before the electric power system fault line fault that record sampling obtains ' _fthe actual mute time t of electric power system fault obtaining with sampling _c;

4) in the electric power system fault state that the acceleration unit in the typical fault that the electric power system fault state that sampling obtains successfully mates obtains in sampling, do not shut down the acceleration unit of the electric power system fault state that being samples obtains; The moment of inertia summation of accelerating unit in the electric power system fault state that sampling obtains is M ' _s;

5) in the electric power system fault state that the deceleration unit in the typical fault that the electric power system fault state that sampling obtains successfully mates obtains in sampling, do not shut down the deceleration unit of the electric power system fault state that being samples obtains; The moment of inertia summation of unit of slowing down in the electric power system fault state that obtains of sampling is M ' _a;

6) press formula M '=M ' _sm ' _a/ (M ' _s+ M ' _a) calculate electric power system equivalent moment of inertia M corresponding to malfunction that electric power system sampling obtains ^';

7) press formula

calculate equivalent critical clearing time t ' _cr;

8) press formula Δ P _m=P ' _f-P _fcalculate the difference Δ P of the front equivalent mechanical power of line fault _m;

9) press formula Δ t _c=t _c-t ' _crcalculate the actual mute time t of electric power system fault that sampling obtains _cwith critical clearing time t ' _crdifference Δ t _c;

10) be calculated as follows the changes delta A that accelerates area _a:

$\begin{array}{c}\mathrm{\Δ}{A}_a=\left\{\begin{array}{c}\frac{1}{2M}[P_m-P_{\mathrm{CD}}+P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_D)]\\ \·[2P_m-2P_{\mathrm{CD}}-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_D)-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_P)]t_{\mathrm{cr}}^{\′}\end{array}\right\}\mathrm{\Δ}{t}_c\\ +\left\{\begin{array}{c}({\mathrm{\δ}}_{\mathrm{cr}}-{\sin }^{-1}\frac{P_m-P_{C0}}{P_{\max 0}}+{\mathrm{\γ}}_0)-\frac{P_m-P_{\mathrm{CD}}}{P_{\max 0}\sqrt{1-{[(P_m-P_{C0})/P_{\max 0}]}^2}}\\ +\frac{P_{\max D}\sin \left({\sin }^{-1}\right[(P_m-P_{C0})/P_{\max 0}]+{\mathrm{\γ}}_0-{\mathrm{\γ}}_D)}{P_{\max 0}\sqrt{1-{[(P_m-P_{C0})/P_{\max 0}]}^2}}\end{array}\right\}\mathrm{\Δ}{P}_m\end{array};$

11) be calculated as follows the changes delta A of retardation area _d:

$\begin{array}{c}{\mathrm{\ΔA}}_d=\left\{\begin{array}{c}\frac{1}{2M}[P_{\mathrm{CP}}-P_m+P_{\max P}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_P)]\\ .[{2P}_m-{2P}_{\mathrm{CD}}-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_D)-P_{\max D}\sin ({\mathrm{\δ}}_{\mathrm{cr}}-{\mathrm{\γ}}_P)]t_{\mathrm{cr}}^{\′}\end{array}\right\}{\mathrm{\Δt}}_c\\ +[{\mathrm{\δ}}_{\mathrm{cr}}+{\sin }^{-1}\frac{P_m-P_{\mathrm{CP}}}{P_{\max P}}-{\mathrm{\γ}}_P-\mathrm{\π}]{\mathrm{\ΔP}}_m\end{array};$

12) the area variation relative with retardation area accelerated in judgement: if Δ A _a-Δ A _d> 0, can think after electric power system fault and will produce Transient Instability; If Δ A _a-Δ A _d≤ 0, can think after electric power system fault it is transient stability.

Images