CN103606952B - A kind of machine of cutting control measure quantization method based on system acceleration energy - Google Patents

Abstract

The invention provides a kind of machine of cutting control measure quantization method based on system acceleration energy, cut machine control measure for transient stability and decision-making foundation is provided, comprising: determine critical machine during multimachine interconnected electric power system unstability; According to critical machine, set up the equivalent one machine infinity bus system model of multimachine interconnected electric power system based on actual measured amount measurement information; The acceleration energy of computing system; Build sets up cutting machine measure quantize solving equation and solve, obtain cutting machine amount calculated value; According to cutting machine amount calculated value, in conjunction with actual generator capacity, cutting machine amount calculated value carries out consolidation process, obtains final actually cutting machine amount; Continue to monitor the dynamic behaviour taking to cut system after machine measure, if system is still tending towards instability status, then calculate next round cut machine amount based on up-to-date measurement information; The method has taken into full account the dynamic characteristic of system, and solution procedure is simple, has good future in engineering applications.

Description

A kind of machine of cutting control measure quantization method based on system acceleration energy

Technical field

The present invention relates to field of power, be specifically related to a kind of machine of cutting control measure quantization method based on system acceleration energy.

Background technology

Transient Stability Control is the important means ensureing power network safety operation, and during transient state merit angle unstability, usually cut machine to sending and control to ensure that System recover is stablized, reasonably cutting machine amount is the key guaranteeing that System recover is stable.Therefore, the quantitative research of cutting machine control measure is the focus that people pay close attention to always.Along with interconnected network scale is increasing, Transient Stability Control is gradually to the future development of " Real-time Decision controls in real time ", and fast quantization method is the prerequisite realizing " controlling in real time ".The development of WAMS in recent years, for " the controlling in real time " realizing transient stability provides technical guarantee.In current existing fast quantization method, no matter be energy function method or extended equal area criterion method, all can make an explanation by homalographic criterion.Use homalographic criterion to ask for based on disturbed geometric locus and cut machine amount, the unstable equilibrium point and taking that must solve system before taking to cut machine control measure cuts the new unstable equilibrium point of system after machine control measure, and then reference area anomalous integral is critical cuts machine amount.Described unstable equilibrium point, respectively by taking before control measure and power balance equation after control measure determines.In order to ask for this two unstable equilibrium points, needing to predict electromagnetic power curve, usually adopting trigonometric function fitting technique to set up power balance equation.

This machine of the cutting quantization method based on homalographic criterion, in the control strategy of " real-time analysis; Real-time Decision ", there is the problem of two aspects: the initial conditions and the end condition that need to determine area integral on the one hand, thus calculate maximum acceleration area and maximum deceleration area.This proposes requirements at the higher level to real-time analysis, needs comprehensive the whole network real time information to judge; Path of integration is difficult to determine on the other hand, the especially calculating of unstable equilibrium point.Usually the trigonometric function fitting technique adopted can not Accurate Prediction electromagnetic power, especially for multimachine Failure Model.This is mainly due under multimachine Failure Model, and the moment that different generator passes through unstable equilibrium point is different.Particularly near unstable equilibrium point, can there is strong distortion in equivalent electromagnetic power.In addition, its cycle of oscillation also there occurs change, is thus difficult to carry out matching with class sine curve.Visible, use law of equal areas to carry out when control measure quantize to solve computationally also inconvenient, in the urgent need to studying easier machine of cutting amount computational methods in engineering reality.

Summary of the invention

The present invention relates to a kind of machine of cutting control measure quantization method based on system acceleration energy, provide decision-making foundation for cutting machine control measure for transient stability, the method comprises:

Step S1, the critical machine after the information determination fault measured by WAMS measurement system during multimachine interconnected electric power system unstability;

Step S2 is the sampling period periodically obtain the multidate information of critical machine by described WAMS measurement system with T, sets up the equivalent one machine infinity bus system model of described multimachine interconnected electric power system;

Step S3, according to described equivalent one machine infinity bus system model, calculates the acceleration energy of described multimachine interconnected electric power system;

Step S4, according to the acceleration energy of described multimachine interconnected electric power system, builds sets up cutting machine measure and quantizes solving equation and solve, obtain cutting machine amount calculated value;

Step S5, cuts machine amount calculated value according to described, and in conjunction with actual generator capacity, cutting machine amount calculated value carries out consolidation process, obtains final actually cutting machine amount;

Step S6, continue to monitor the dynamic behaviour taking to cut multimachine interconnected electric power system after machine control measure, if system is still tending towards instability status, then calculate next round cut machine amount based on up-to-date measurement information, the value arranging i is i=i+T, performs step S1.

Further, in described step S1, the critical machine after the information determination fault measured by WAMS measurement system during multimachine system unstability, needs the power-angle curve based on the whole network generator to judge.

Further, in described step S2, after fault, begin through the dynamic feature information that described WAMS measurement system periodically obtains critical machine, the sampling period T of described contact section dynamic feature information is identical with the sampling period of the PMU measuring unit in described WAMS measurement system;

The dynamic feature information of described critical machine comprises not the mechanical output of generator input in the same time, the active power of output, generator's power and angle and speed discrepancy; Wherein, after fault, the mechanical output of the i-th moment kth platform generator input is the active power exported is generator's power and angle is speed discrepancy is

Further, in described step S2, according to the dynamic feature information of critical machine, set up the equivalent one machine infinity bus system model of multimachine interconnected electric power system, its method is:

Suppose that critical machine is leading group S and delayed group A, then equivalent two machine systems are:

$\frac{{\mathrm{d\δ}}_S}{\mathrm{dt}}={\mathrm{\ω}}_S$ And $M_S\frac{{\mathrm{d\ω}}_S}{\mathrm{dt}}=P_{\mathrm{mS}}-P_{\mathrm{eS}}$

$\frac{{\mathrm{d\δ}}_A}{\mathrm{dt}}={\mathrm{\ω}}_A$ And $M_A\frac{{\mathrm{d\ω}}_A}{\mathrm{dt}}=P_{\mathrm{mA}}-P_{\mathrm{eA}}$

Wherein: ${\mathrm{\δ}}_S=\frac{\mathrm{\Σ}{M}_i{\mathrm{\δ}}_i}{\mathrm{\Σ}{M}_i};\frac{d{\mathrm{\ω}}_S}{\mathrm{dt}}=\frac{\mathrm{\Σ}{M}_i({\mathrm{d\ω}}_i/\mathrm{dt})}{\mathrm{\Σ}{M}_i};M_S=\mathrm{\Σ}{M}_i;P_{\mathrm{mS}}=\mathrm{\Σ}{P}_{\mathrm{mi}};P_{\mathrm{eS}}=\mathrm{\Σ}{P}_{\mathrm{ei}}(i\∈S);$

${\mathrm{\δ}}_A=\frac{\mathrm{\Σ}{M}_k{\mathrm{\δ}}_k}{\mathrm{\Σ}{M}_k};\frac{d{\mathrm{\ω}}_A}{\mathrm{dt}}=\frac{\mathrm{\Σ}{M}_k({\mathrm{d\ω}}_k/\mathrm{dt})}{\mathrm{\Σ}{M}_k};M_A=\mathrm{\Σ}{M}_k;P_{\mathrm{mA}}=\mathrm{\Σ}{P}_{\mathrm{mk}};P_{\mathrm{eA}}=\mathrm{\Σ}{P}_{\mathrm{ek}}(k\∈A);$

Definition:

δ=δ _S-δ _A；ω=ω _S-ω _A；

$P_m=\frac{M_A{P}_{\mathrm{mS}}-M_S{P}_{\mathrm{mA}}}{M_S+M_A};$ $P_e=\frac{M_A{P}_{\mathrm{eS}}-M_S{P}_{\mathrm{eA}}}{M_S+M_A}$

Then equivalent one machine infinity bus system is:

$\left\{\begin{array}{c}\frac{\mathrm{d\δ}}{\mathrm{dt}}=\mathrm{\ω}\\ M\frac{\mathrm{d\ω}}{\mathrm{dt}}=P_m-P_e\end{array}\right.$

Wherein, δ represents merit angle, P _mrepresent equivalent mechanical output, P _erepresent equivalent electromagnetic power.

Further, in described step S3, according to equivalent one machine infinity bus system model, the acceleration energy of computing system, its method is:

Based on equivalent one machine infinity bus system model, the correction transient state kinetic energy E of multimachine interconnected electric power system _{k_co}, revise transient potential energy E _{p_co}and total system correction transient state energy E _corelation can be defined as follows:

$E_{\mathrm{co}}=E_{k\_\mathrm{co}}+E_{p\_\mathrm{co}}=\frac{1}{2}M{\mathrm{\ω}}^2+{\∫}_{{\mathrm{\δ}}_s}^{{\mathrm{\δ}}_e}(P_e-P_m)\mathrm{d\δ}$

Due to the transient state energy E revised _cobe conservation in process after a failure, therefore have:

E _{k_co}+E _{p_co}=C

Wherein C is a constant.

According to the imbalance power of equation of rotor motion, the acceleration energy of definable i moment multimachine interconnected systems is as follows:

$E_{\mathrm{acc}}^i={\∫}_{{\mathrm{\δ}}_0}^{{\mathrm{\δ}}_i}(P_m-P_e)\mathrm{d\δ}$

Wherein δ ₀represent merit angle during stable state, δ _irepresent the merit angle in i moment.

Further, in described step S4, according to the acceleration energy of system, build sets up cutting machine measure and quantize solving equation and solve, obtain cutting machine amount calculated value, its method is:

If cutting the machine measure enforcement moment is t _k, the machine amount of cutting is △ P _m, System recover is stablized, then:

${\∫}_{{\mathrm{\δ}}_0}^{{\mathrm{\δ}}_k}(P_m-P_e)\mathrm{d\δ}+{\∫}_{{\mathrm{\δ}}_k}^{{\mathrm{\δ}}_{\max }^{\′}}(P_m-\mathrm{\Δ}{P}_m-P_e)\mathrm{d\δ}=0$

Wherein δ ₀(t during expression stable state ₀moment) merit angle, for t _kin place cycle of oscillation, system is at the merit angle at solstics place, then can obtain cutting machine amount and quantize solving equation:

${\∫}_{{\mathrm{\δ}}_k}^{{\mathrm{\δ}}_{\max }^{\′}}(P_e-(P_m-\mathrm{\Δ}{P}_m))\mathrm{d\δ}=\frac{1}{2}M{\mathrm{\ω}}_k^2$

Have according to area integral formula:

$\frac{1}{2}\underset{i=k}{\overset{n}{\mathrm{\Σ}}}\left\{\right[(P_e^i-P_m^i+\mathrm{\Δ}{P}_m)+(P_e^{(i+1)}-P_m^{(i+1)}+\mathrm{\Δ}{P}_m)]\×({\mathrm{\δ}}^i-{\mathrm{\δ}}^{i+1})\}=\frac{1}{2}M{\mathrm{\ω}}_k^2$

In formula, n is determined by following integration end condition:

or δ ⁿ>=δ ^n-1aMP.AMp.Amp δ ⁿ>=δ ⁿ⁺¹

represent and cut the instantaneous correction kinetic energy in machine moment, this instantaneous correction kinetic energy both tried to achieve (integration can from the arbitrary stable state moment before system is disturbed) by integration, also can calculate in real time based on the measurement information of WAMS.Electromagnetic power curve after integration track can adopt Self-regression Forecast Model to dope respectively to cut machine measure and power-angle curve then, given initial value △ P _m=0, and adopt the method for iterative computation to try to achieve to cut machine amount calculated value.

Further, in described step S5, according to actual generator capacity, " upwards consolidation " method cutting machine amount calculated value is taked to carry out consolidation process, namely select to be greater than the smallest discrete value of cutting machine amount calculated value and to cut machine amount as actual, with ensure actual cut machine time excise the combination of whole generator or several generators.The electrical network main force of current China generator capacity, mainly contains 125MW, 200MW, 300MW, 600MW, 1000MW equal-specification.。

Beneficial effect of the present invention comprises:

A kind of machine of cutting control measure Quantitative Calculation Method based on system acceleration energy provided by the invention, the critical machine of the information identification multimachine interconnected electric power system measured by WAMS measurement system also sets up the equivalent one machine infinity bus system model of multimachine interconnected electric power system, the acceleration energy of computing system, acceleration energy based on system is built sets up cutting machine measure and is quantized solving equation and solve, obtain cutting machine amount calculated value, in conjunction with actual generator capacity, cutting machine amount calculated value carries out consolidation process, obtains final actually cutting machine amount.Continue to monitor the dynamic behaviour taking to cut system after machine measure, if system is still tending towards instability status, then calculate next round cut machine amount, for transient stability emergency control provides decision-making foundation based on up-to-date measurement information.

The method is completely based on real-time measurement information, and the real-time response information that wherein mechanical output, electromagnetic power, merit angle all can be measured by WAMS measurement system directly obtains, and makes integral and calculating process simple, makes the method have more practicality.

Accompanying drawing explanation

Fig. 1 is a kind of machine of cutting control measure quantization method flow chart based on system acceleration energy provided by the invention;

Fig. 2 is New England 10 provided by the invention machine 39 node system winding diagram;

Fig. 3 is the whole network generator's power and angle curve after fault provided by the invention;

Fig. 4 is equivalent one machine infinity bus system system mechanics power provided by the invention, electromagnetic power curve;

Fig. 5 is the whole network generator's power and angle curve after the first round cut machine measure provided by the invention;

Fig. 6 is equivalent generator's power and angle curve after the first round cut machine measure provided by the invention;

Fig. 7 is the whole network generator's power and angle curve after the second round cut machine measure provided by the invention;

Fig. 8 is equivalent generator's power and angle curve after the second round cut machine measure provided by the invention;

Fig. 9 is the voltage curve after the second round cut machine measure provided by the invention near fault point.

Embodiment

A kind of machine of cutting control measure quantization method based on system acceleration energy provided by the invention, pass through WAMS(WideAreaMeasurementSystem, wide-area monitoring systems) critical machine of information identification multimachine interconnected electric power system measured of measurement system set up the equivalent one machine infinity bus system model of multimachine interconnected electric power system, the acceleration energy of computing system, acceleration energy based on system is built sets up cutting machine measure and is quantized solving equation and solve, obtain cutting machine amount calculated value, in conjunction with actual generator capacity, cutting machine amount calculated value carries out consolidation process, obtain final actually cutting machine amount.Concrete, as shown in Figure 1, as shown in Figure 1, the method comprises the flow chart of the method:

Step S1, the critical machine after the information determination fault measured by WAMS measurement system during described multimachine interconnected electric power system unstability;

Step S2 is the sampling period periodically obtain the multidate information of critical machine by described WAMS measurement system with T, sets up the equivalent one machine infinity bus system model of multimachine interconnected electric power system;

Step S3, according to equivalent one machine infinity bus system model, the acceleration energy of computing system;

Step S4, according to the acceleration energy of system, builds sets up cutting machine measure and quantizes solving equation and solve, obtain cutting machine amount calculated value;

Step S5, according to cutting machine amount calculated value, in conjunction with actual generator capacity, cutting machine amount calculated value carries out consolidation process, obtains final actually cutting machine amount;

Step S6, continue to monitor the dynamic behaviour taking to cut system after machine measure, if system is still tending towards instability status, then calculate next round cut machine amount based on up-to-date measurement information, the value arranging i is i=i+T, performs step S1.

Embodiment one:

Embodiment one provided by the invention is the embodiment of a kind of machine of cutting control measure Quantitative Calculation Method based on system acceleration energy provided by the invention.

Concrete, based on machine of the cutting control measure quantum chemical method of system acceleration energy in this embodiment, after fault, begin through WAMS system measure.

In step S1, by the critical machine of multimachine interconnected electric power system after the metrical information determination fault of WAMS systematic survey.

In step S2, after fault, begin through WAMS measurement system periodically obtain critical machine dynamic feature information, PMU (PhasorMeasurementUnit in the sampling period T of this contact section dynamic feature information and WAMS measurement system, synchronous phase angle measuring unit) sampling period of measuring unit is identical, comprises not the mechanical output of generator input in the same time, the active power of output, generator's power and angle and speed discrepancy; Wherein, after fault, the mechanical output of the i-th moment kth platform generator input is the active power exported is generator's power and angle is speed discrepancy is

According to critical machine actual measurement response message based on the principle of machine of the cutting control measure quantum chemical method of system acceleration energy and method be:

According to the multidate information of critical machine, set up the equivalent one machine infinity bus system model of multimachine interconnected electric power system.Suppose that critical machine is leading group S and delayed group A, then equivalent two machine systems are:

$\frac{{\mathrm{d\δ}}_S}{\mathrm{dt}}={\mathrm{\ω}}_S$ And $M_S\frac{{\mathrm{d\ω}}_S}{\mathrm{dt}}=P_{\mathrm{mS}}-P_{\mathrm{eS}}$

$\frac{{\mathrm{d\δ}}_A}{\mathrm{dt}}={\mathrm{\ω}}_A$ And $M_A\frac{{\mathrm{d\ω}}_A}{\mathrm{dt}}=P_{\mathrm{mA}}-P_{\mathrm{eA}}$

Wherein: ${\mathrm{\δ}}_S=\frac{\mathrm{\Σ}{M}_i{\mathrm{\δ}}_i}{\mathrm{\Σ}{M}_i};\frac{d{\mathrm{\ω}}_S}{\mathrm{dt}}=\frac{\mathrm{\Σ}{M}_i({\mathrm{d\ω}}_i/\mathrm{dt})}{\mathrm{\Σ}{M}_i};M_S=\mathrm{\Σ}{M}_i;P_{\mathrm{mS}}=\mathrm{\Σ}{P}_{\mathrm{mi}};P_{\mathrm{eS}}=\mathrm{\Σ}{P}_{\mathrm{ei}}(i\∈S);$

${\mathrm{\δ}}_A=\frac{\mathrm{\Σ}{M}_k{\mathrm{\δ}}_k}{\mathrm{\Σ}{M}_k};\frac{d{\mathrm{\ω}}_A}{\mathrm{dt}}=\frac{\mathrm{\Σ}{M}_k({\mathrm{d\ω}}_k/\mathrm{dt})}{\mathrm{\Σ}{M}_k};M_A=\mathrm{\Σ}{M}_k;P_{\mathrm{mA}}=\mathrm{\Σ}{P}_{\mathrm{mk}};P_{\mathrm{eA}}=\mathrm{\Σ}{P}_{\mathrm{ek}}(k\∈A);$

Definition:

δ=δ _S-δ _A；ω=ω _S-ω _A；

$P_m=\frac{M_A{P}_{\mathrm{mS}}-M_S{P}_{\mathrm{mA}}}{M_S+M_A};$ $P_e=\frac{M_A{P}_{\mathrm{eS}}-M_S{P}_{\mathrm{eA}}}{M_S+M_A}$

Then equivalent one machine infinity bus system is:

$\left\{\begin{array}{c}\frac{\mathrm{d\δ}}{\mathrm{dt}}=\mathrm{\ω}\\ M\frac{\mathrm{d\ω}}{\mathrm{dt}}=P_m-P_e\end{array}\right.$

In step S3, according to equivalent one machine infinity bus system model, the acceleration energy of computing system, its method is:

Based on equivalent one machine infinity bus system model, the correction transient state kinetic energy E of multimachine interconnected systems _{k_co}, revise transient potential energy E _{p_co}and total system correction transient state energy E _cocan be defined as follows:

$E_{\mathrm{co}}=E_{k\_\mathrm{co}}+E_{p\_\mathrm{co}}=\frac{1}{2}M{\mathrm{\ω}}^2+{\∫}_{{\mathrm{\δ}}_s}^{{\mathrm{\δ}}_e}(P_e-P_m)\mathrm{d\δ}$

Because the transient state energy revised is conservation in process after a failure, therefore have:

E _{k_co}+E _{p_co}=C

Wherein C is a constant.

According to the imbalance power of equation of rotor motion, the acceleration energy of definable i moment multimachine interconnected systems is as follows:

$E_{\mathrm{acc}}^i={\∫}_{{\mathrm{\δ}}_0}^{{\mathrm{\δ}}_i}(P_m-P_e)\mathrm{d\δ}$

Wherein δ ₀represent merit angle during stable state, δ _irepresent the merit angle in i moment.

In step S4, according to the acceleration energy of system, build sets up cutting machine measure and quantize solving equation and solve, obtain cutting machine amount calculated value, its method is:

If cutting the machine measure enforcement moment is t _k, the machine amount of cutting is △ P _m, System recover is stablized, then:

${\∫}_{{\mathrm{\δ}}_0}^{{\mathrm{\δ}}_k}(P_m-P_e)\mathrm{d\δ}+{\∫}_{{\mathrm{\δ}}_k}^{{\mathrm{\δ}}_{\max }^{\′}}(P_m-\mathrm{\Δ}{P}_m-P_e)\mathrm{d\δ}=0$

Wherein δ ₀represent t ₀the merit angle in moment, for t _kin place cycle of oscillation, system is at the merit angle at solstics place, then can obtain cutting machine amount and quantize solving equation:

${\∫}_{{\mathrm{\δ}}_k}^{{\mathrm{\δ}}_{\max }^{\′}}(P_e-(P_m-\mathrm{\Δ}{P}_m))\mathrm{d\δ}=\frac{1}{2}M{\mathrm{\ω}}_k^2$

Have according to area integral formula:

$\frac{1}{2}\underset{i=k}{\overset{n}{\mathrm{\Σ}}}\left\{\right[(P_e^i-P_m^i+\mathrm{\Δ}{P}_m)+(P_e^{(i+1)}-P_m^{(i+1)}+\mathrm{\Δ}{P}_m)]\×({\mathrm{\δ}}^i-{\mathrm{\δ}}^{i+1})\}=\frac{1}{2}M{\mathrm{\ω}}_k^2$

In formula, n is determined by following integration end condition:

or δ ⁿ>=δ ^n-1aMP.AMp.Amp δ ⁿ>=δ ⁿ⁺¹

Cut the instantaneous correction kinetic energy in machine moment on the right side of formula, both by integration try to achieve (integration can from system disturbed before arbitrary stable state moment), also can calculate in real time based on the measurement information of WAMS.Electromagnetic power curve after integration track can adopt Self-regression Forecast Model to dope respectively to cut machine measure and power-angle curve.On this basis, given initial value △ P _m=0, adopt the method for iterative computation can try to achieve final machine of cutting amount.

In step S5, according to cutting machine amount calculated value, in conjunction with actual generator capacity, cutting machine amount calculated value carries out consolidation process, obtains final actually cutting machine amount; The electrical network main force of current China generator capacity, mainly contains 125MW, 200MW, 300MW, 600MW, 1000MW equal-specification.Take the principle of " upwards consolidation " to carry out consolidation, select the smallest discrete value being greater than amount of calculation to cut machine amount as actual, with ensure actual cut machine time excise the combination of whole generator or several generators.

In step S6, continue to monitor the dynamic behaviour taking to cut system after machine measure, if system is still tending towards instability status, then calculate next round cut machine amount based on up-to-date measurement information, the value arranging i is i=i+T, performs step S1.

Embodiment two:

The embodiment two of a kind of machine of cutting control measure Quantitative Calculation Method based on system acceleration energy provided by the invention is with machine of cutting control measure Quantitative Calculation Method embodiment during New England 10 machine 39 node system unstability, adopt the Based on Power System Analysis Software Package (PSASP) of China Electric Power Research Institute's exploitation, the disturbance response data obtained with simulated program simulate the real-time measurement data of WAMS.Generator adopts classical second-order model, and load adopts constant-impedance model.Fault condition is that three-phase ground short circuit occurs bus16-bus17, and trouble duration is 0.20s, excises this circuit afterwards, system unstability.According to initial trend, this system can be divided into three region control subsystem, and wherein sending end region is Area1, be Area3, Area2 is self-balancing subsystem by end regions, as shown in Figure 2.

Step S1': the disturbance response data obtained by simulated program simulate the real-time measurement data of wide area measurement system, determine critical machine.In this example, the whole network generator's power and angle curve as shown in Figure 3, can obtain leading group S and delayed group A is respectively: S={G33, G34, G35, G36}, A={G30, G31, G32, G37, G38, G39}.

Step S2': be the sampling period periodically obtain the multidate information of critical machine by described WAMS measurement system with T, sets up the equivalent one machine infinity bus system model of multimachine interconnected electric power system.The mechanical output of the equivalent one machine infinity bus system model of gained and electromagnetic power are as shown in Figure 4.

Step S3': according to equivalent one machine infinity bus system model, the acceleration energy of computing system.System acceleration energy computing formula is as follows:

$E_{\mathrm{acc}}^i={\∫}_{{\mathrm{\δ}}_0}^{{\mathrm{\δ}}_i}(P_m-P_e)\mathrm{d\δ}$

Integral and calculating from moment 0s occurs fault, end time is 1.87s.

Step S4': according to the acceleration energy of system, builds sets up cutting machine measure and quantizes solving equation and solve, obtain cutting machine amount calculated value.Cutting the machine measure enforcement moment is 1.87s, and the machine amount of cutting is △ P _mif System recover is stablized, then:

${\∫}_{{\mathrm{\δ}}_k}^{{\mathrm{\δ}}_{\max }^{\′}}(P_e-(P_m-\mathrm{\Δ}{P}_m))\mathrm{d\δ}=\frac{1}{2}M{\mathrm{\ω}}_k^2$

Have according to area integral formula:

$\frac{1}{2}\underset{i=k}{\overset{n}{\mathrm{\Σ}}}\left\{\right[(P_e^i-P_m^i+\mathrm{\Δ}{P}_m)+(P_e^{(i+1)}-P_m^{(i+1)}+\mathrm{\Δ}{P}_m)]\×({\mathrm{\δ}}^i-{\mathrm{\δ}}^{i+1})\}=\frac{1}{2}M{\mathrm{\ω}}_k^2$

As shown in Figure 4, cut machine amount calculated value is 0.7511 (p.u.) to electromagnetic power prediction curve.

Step S5': according to cutting machine amount calculated value, in conjunction with actual generator capacity, cutting machine amount calculated value carries out consolidation process, obtains final actually cutting machine amount.Getting fiducial value is 1000MVA, then cutting machine amount calculated value is 751.1MW, and upwards consolidation is 800MW, can excise two 300MW generators and a 200MW generator, or a 600MW generator and a 200MW generator.

Step S6': the first round cut machine can be cut machine to G36 generator and controls and continue to monitor the dynamic behaviour taking to cut system after machine measure, and discovery system is still tending towards instability status, and generator's power and angle curve and equivalent power-angle curve are as shown in Figure 5, Figure 6.Calculate the second round cut machine amount based on up-to-date measurement information, the second round cut machine time was 1.97s, and calculated value is 0.4812 (p.u.).Upwards consolidation is 500MW, can excise a 300MW generator and a 200MW generator.Second round cut machine can be cut machine to G35 generator and control, and cut voltage curve near the generator's power and angle curve after machine, equivalent power-angle curve and defect center as shown in figs. 7 to 9, known system tends towards stability.

Finally should be noted that: above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit; in conjunction with above-described embodiment to invention has been detailed description; those of ordinary skill in the field are to be understood that: various equivalent, the deformation process that those skilled in the art carries out according to this concrete technical scheme, also within protection scope of the present invention.

Claims (7)

1., based on machine of cutting a control measure quantization method for system acceleration energy, it is characterized in that, described method comprises:

Step S1, the critical machine after the information determination fault measured by WAMS measurement system during multimachine interconnected electric power system unstability;

Step S2 is the sampling period periodically obtain the dynamic feature information of critical machine by described WAMS measurement system with T, sets up the equivalent one machine infinity bus system model of multimachine interconnected electric power system;

Step S3, according to described equivalent one machine infinity bus system model, calculates the acceleration energy of multimachine interconnected electric power system;

Step S4, according to the acceleration energy of described multimachine interconnected electric power system, builds sets up cutting machine measure and quantizes solving equation and solve, obtain cutting machine amount calculated value;

Step S5, cuts machine amount calculated value according to described, and in conjunction with actual generator capacity, cutting machine amount calculated value carries out consolidation process, obtains final actually cutting machine amount;

Step S6, continue to monitor the dynamic behaviour taking to cut multimachine interconnected electric power system after machine control measure, if system is still tending towards instability status, then calculate next round cut machine amount based on up-to-date measurement information, the value arranging for the i-th moment is i=i+T, performs step S1.

2. the method for claim 1, is characterized in that, in described step S1, based on the critical machine after the power-angle curve of the whole network generator, the information determination fault measured by WAMS measurement system during multimachine system unstability.

3. the method for claim 1, it is characterized in that, in described step S2, after fault, begin through the dynamic feature information that described WAMS measurement system periodically obtains critical machine, the sampling period T of described critical machine dynamic feature information is identical with the sampling period of the PMU measuring unit in described WAMS measurement system;

The dynamic feature information of described critical machine comprises not the mechanical output of generator input in the same time, the active power of output, generator's power and angle and speed discrepancy; Wherein, after fault, the mechanical output of the i-th moment kth platform generator input is the active power exported is generator's power and angle is speed discrepancy is

4. method as claimed in claim 3, it is characterized in that, in described step S2, according to the dynamic feature information of critical machine, set up the equivalent one machine infinity bus system model of multimachine interconnected electric power system, its method is:

Suppose that critical machine is leading group S and delayed group A, then equivalent two machine systems are:

$\frac{{\mathrm{d\δ}}_S}{dt}={\mathrm{\ω}}_S$ And $M_S\frac{{\mathrm{d\ω}}_S}{dt}=P_{mS}-P_{eS}$

$\frac{{\mathrm{d\δ}}_A}{dt}={\mathrm{\ω}}_A$ And $M_A\frac{{\mathrm{d\ω}}_A}{dt}=P_{mA}-P_{eA}$

Wherein, m _s=Σ M _i; P _mS=Σ P _mi; P _eS=Σ P _ei(i ∈ S);

M _A＝ΣM _k；P _mA＝ΣP _mk；P _eA＝ΣP _ek(k∈A)；

Definition:

δ＝δ _S-δ _A；ω＝ω _S-ω _A；

$P_m=\frac{M_A{P}_{mS}-M_S{P}_{mA}}{M_S+M_A};P_e=\frac{M_A{P}_{eS}-M_S{P}_{eA}}{M_S+M_A}$

Then equivalent one machine infinity bus system is:

$\left\{\begin{array}{c}\frac{d\mathrm{\δ}}{dt}=\mathrm{\ω}\\ M\frac{d\mathrm{\ω}}{dt}=P_m-P_e\end{array}\right.$

Wherein, δ represents merit angle, P _mrepresent equivalent mechanical output, P _erepresent equivalent electromagnetic power.

5. method as claimed in claim 4, is characterized in that, in described step S3, according to equivalent one machine infinity bus system model, and the acceleration energy of computing system, its method is:

Based on equivalent one machine infinity bus system model, the correction transient state kinetic energy E of multimachine interconnected electric power system _{k_co}, revise transient potential energy E _{p_co}and total system correction transient state energy E _cocontextual definition as follows:

$E_{co}=E_{k\_co}+E_{p\_co}=\frac{1}{2}{\mathrm{M\ω}}^2+{\∫}_{\mathrm{\δ}s}^{{\mathrm{\δ}}_e}(P_e-P_m)d\mathrm{\δ}$

Owing to revising transient state energy E _cobe conservation in process after a failure, therefore have:

$E_{k\_co}+E_{p\_co}=C$

Wherein C is a constant;

According to the imbalance power of equation of rotor motion, the acceleration energy of definition i moment multimachine interconnected electric power system is as follows:

$E_{acc}^i={\∫}_{{\mathrm{\δ}}_0}^{{\mathrm{\δ}}_i}(P_m-P_e)d\mathrm{\δ}$

Wherein, δ ₀represent merit angle during stable state, δ _irepresent the merit angle in i moment.

6. method as claimed in claim 5, is characterized in that, in described step S4, according to the acceleration energy of system, build sets up cutting machine measure and quantize solving equation and solve, obtain cutting machine amount calculated value, its method is:

If cutting the machine measure enforcement moment is t _k, the machine amount of cutting is Δ P _m, System recover is stablized, then:

${\∫}_{{\mathrm{\δ}}_0}^{{\mathrm{\δ}}_k}(P_m-P_e)d\mathrm{\δ}+{\∫}_{{\mathrm{\δ}}_k}^{{\mathrm{\δ}}_{\max }^{\′}}(P_m-{\mathrm{\ΔP}}_m-P_e)d\mathrm{\δ}=0$

Wherein, δ ₀represent merit angle during stable state, δ ' _maxfor t _kin place cycle of oscillation, system is at the merit angle at solstics place, then obtain cutting machine amount and quantize solving equation:

${\∫}_{{\mathrm{\δ}}_k}^{{\mathrm{\δ}}_{\max }^{\′}}(P_e-(P_m-{\mathrm{\ΔP}}_m\left)\right)d\mathrm{\δ}=\frac{1}{2}{\mathrm{M\ω}}_k^2$

Have according to area integral formula:

$\frac{1}{2}\underset{i=k}{\overset{n}{\Σ}}\{\[(P_e^i-P_m^i+{\mathrm{\ΔP}}_m)+(P_e^{(i+1)}-P_m^{(i+1)}+{\mathrm{\ΔP}}_m)\]\×({\mathrm{\δ}}^i-{\mathrm{\δ}}^{i+1})\}=\frac{1}{2}{\mathrm{M\ω}}_k^2$

In formula, n is determined by following integration end condition:

for cutting the instantaneous correction kinetic energy in machine moment, the information that this instantaneous correction kinetic energy is tried to achieve by integral algorithm or measured based on WAMS measurement system from the arbitrary stable state moment before system is disturbed is tried to achieve in real time;

First, adopt Self-regression Forecast Model to dope the electromagnetic power curve after cutting machine measure and power-angle curve respectively as integration track, then, given initial value Δ P _m=0, adopt iterative calculation method to try to achieve and cut machine amount calculated value.

7. method as claimed in claim 3, it is characterized in that, in described step S5, according to actual generator capacity, take upwards consolidation method cutting machine amount calculated value to carry out consolidation process, namely select to be greater than the smallest discrete value of cutting machine amount calculated value and cut machine amount as actual.