CN104680323A - Energy stability-domain building system and method for power system - Google Patents

Abstract

The invention provides an energy stability-domain building system and method for a power system. The energy stability-domain building system comprises a data acquisition module, a system dynamic-equation generating module, a damping energy solution module, an energy stability-domain building module and a result output module, wherein the data acquisition module is used for acquiring network structure parameters, and the frequency and the power angle of an engine in the system; the system dynamic-equation generating module is used for obtaining the dynamic equation of the system; the damping energy solution module is used for calculating the damping energy accumulated in the armature reaction of the engine of the system during one cyclic wave oscillation; the energy stability-domain building module is used for building an energy stability domain of the power system, which reflects the dynamic stability and the transient stability of the system; the result output module is used for outputting the energy stability domain of the power system. Through the adoption of the energy stability-domain building system and method for the power system, provided by the invention, the static stability and the dynamic stability of the system can be reflected, and the accuracy is higher.

Description

Electric system energy stabilization territory constructing system and method

Technical field

The present invention relates to technical field of power systems, refer more particularly to stability of power system analytic system and method.

Background technology

Along with the fast development of modern power systems, the features such as grid equipment variation, information diversification, the method for operation changeableization are further obvious, the deficiency such as information dualization, model deterministic that deterministic type security conceives to expose has been difficult to meet people for the more safe and reliable requirement of electric energy, under these circumstances, the analysis means in " territory " becomes the important measures of a kind of power system safety and stability research gradually.

According to the division that IEEE analyzes power system security, the stability of power system research at present based on territory is mainly divided into Steady State Security Region (Steady-State Security Region) and Dynamic Security Region (Dynamic Security Region).Steady State Security Region is the set being defined in node injecting power space, vector is injected for any one in this set, must meet trend can separate and small disturbance stability two constraint conditions, therefore, Steady State Security Region is the common factor of load flow feasible region and Small Signal Stability Region simultaneously.And Dynamic Security Region is in node injecting power space, after making accident system still keep transient stability the set of likely operating point.As can be seen from above-mentioned definition, Steady State Security Region can analytic system stable state time security, but lack consideration to disturbance factor, and Dynamic Security Region can ensure the first pendulum stability of system, but lack the analysis to system subsequent dynamic stability.Visible, single Steady State Security Region or Dynamic Security Region all cannot the dynamic stabilities of system after analysis of failure, how to build that to take into account the two advantage and make up the two not enough comprehensive safety territory be the key solving this problem.

Summary of the invention

In view of this, object of the present invention is intended to overcome deficiency of the prior art, avoids single Steady State Security Region or Dynamic Security Region method all cannot the problem of the dynamic stability of system after analysis of failure, plays the effect building and take into account the two advantage.

First the present invention utilizes the wide area signal data of reading in that system is carried out linearization expansion at non-equilibrium some place, obtains system dynamic equation.Secondly, by generator armature course of reaction time mutative damp component be defined as dynamic antivibration, on this basis, take into full account in oscillatory process time become factor, ask for generator armature in system and react the damping capacity accumulated in a cycle oscillatory process.Then, in parameter-energy hyperspace, according to considering that the power system dynamic stability criterion of disturbance size and system state draws out the electric system energy stabilization territory intuitively can reflecting system dynamic stability and transient stability simultaneously.Simulation result based on four machine two district systems shows that the system capacity stable region constructed by the present invention has higher accuracy.System potential risk, for guidance system management and running, is learned in the energy stabilization territory utilizing the present invention to be formed, and formulates control program, ensures that security of system stable operation is significant.

In order to realize this object, the technical scheme that the present invention takes is as follows.

A kind of electric system energy stabilization territory constructing system, described system comprise connect successively data acquisition module, system dynamic equation generation module, damping capacity solves module, energy stabilization territory builds module and result output module;

Wherein, data acquisition module is used for generator frequency, merit angle in collection network structural parameters, system, and image data is sent to system dynamic equation generation module;

The dynamic equation of system dynamic equation generation module for utilizing the data of reading in system to be launched the system that obtains at non-equilibrium some place;

Damping capacity solves module and reacts for asking for generator armature in system the damping capacity accumulated in a cycle oscillatory process;

Energy stabilization territory builds module for the power system dynamic stability criterion according to disturbance size and system state, builds the electric system energy stabilization territory of reflection system dynamic stability and transient stability;

Result output module is used for output power system capacity stable region.

Wherein, the system dynamic equation that system dynamic equation generation module obtains is:

$\mathrm{\Δ}{\stackrel{\·}{x}}_k=A_k({\mathrm{\Δx}}_k+c),$

Wherein, c=A _k ^-1f (x _k, y _k),

$A_k={\frac{\∂f}{\∂x}|}_k,$

${\stackrel{\·}{x}}_k=f(x_k,y_k),$

X _kand y _kbe respectively quantity of state and the algebraic quantity of point k place system, Δ x _kfor x _kknots modification.

In addition, damping capacity solves the damping capacity that module asks for and is:

$E_{\mathrm{Di}}=\underset{k=0}{\overset{T}{\mathrm{\Σ}}}\frac{1}{2}{\mathrm{\Δ\δ}}_i(K_{\mathrm{ek}}{v}_{\mathrm{\δk}}+D_{\mathrm{ek}}({\mathrm{\Δ\ω}}_i+r_{\mathrm{\ωk}})),$

Wherein, $\left[\begin{array}{c}{r}_{\mathrm{\δk}}+{\mathrm{jv}}_{\mathrm{\δk}}\\ r_{\mathrm{\ωk}}+{\mathrm{jv}}_{\mathrm{\ωk}}\end{array}\right]={A_k}^{-1}\left[\begin{array}{c}{\stackrel{\·}{\mathrm{\δ}}}_k\\ {\stackrel{\·}{\mathrm{\ω}}}_k\end{array}\right],$

Δ δ _i, Δ ω _ibe respectively i-th generator's power and angle variable quantity and rotation speed change amount,

K _ekand D _ekbe respectively t _kmoment generator synchronization factor and ratio of damping.

A kind of electric system energy stabilization territory construction method, described method comprises step:

Generator frequency, merit angle in A, collection time lag system network architecture parameters, system;

System is launched the dynamic equation of the system that obtains by the data that B, utilization gather at non-equilibrium some place;

C, ask for generator armature in system and react the damping capacity accumulated in a cycle oscillatory process;

D, power system dynamic stability criterion according to disturbance size and system state, build the electric system energy stabilization territory of reflection system dynamic stability and transient stability;

E, export described electric system energy stabilization territory.

The system dynamic equation obtained in stepb is:

$\mathrm{\Δ}{\stackrel{\·}{x}}_k=A_k({\mathrm{\Δx}}_k+c),$

Wherein, c=A _k ^-1f (x _k, y _k),

$A_k={\frac{\∂f}{\∂x}|}_k,$

${\stackrel{\·}{x}}_k=f(x_k,y_k),$

X _kand y _kbe respectively quantity of state and the algebraic quantity of point k place system, Δ x _kfor x _kknots modification.。

The damping capacity obtained in step C is in addition:

$E_{\mathrm{Di}}=\underset{k=0}{\overset{T}{\mathrm{\Σ}}}\frac{1}{2}{\mathrm{\Δ\δ}}_i(K_{\mathrm{ek}}{v}_{\mathrm{\δk}}+D_{\mathrm{ek}}({\mathrm{\Δ\ω}}_i+r_{\mathrm{\ωk}})),$

Wherein, $\left[\begin{array}{c}{r}_{\mathrm{\δk}}+{\mathrm{jv}}_{\mathrm{\δk}}\\ r_{\mathrm{\ωk}}+{\mathrm{jv}}_{\mathrm{\ωk}}\end{array}\right]={A_k}^{-1}\left[\begin{array}{c}{\stackrel{\·}{\mathrm{\δ}}}_k\\ {\stackrel{\·}{\mathrm{\ω}}}_k\end{array}\right],$

Δ δ _i, Δ ω _ibe respectively i-th generator's power and angle and rotation speed change amount,

K _ekand D _ekbe respectively t _kmoment generator synchronization factor and ratio of damping.

In step D, the power system dynamic stability criterion of disturbance size and system state comprises:

System ensures that under current operating condition in the damping of equilibrium point be just;

After disturbance in first cycle, the damping capacity that generator armature reaction produces and the damping capacity sum that generator windings, mechanical damping produce are greater than zero;

The transient state energy accumulation that fault causes is no more than the max-thresholds that system can be born.

Determine in step D that electric system energy stabilization territory comprises:

D1, adopt Small Signal Stability Region method for solving determination energy stabilization territory bottom surface D at parameter space, described energy stabilization territory bottom surface D meets system under current operating condition, ensures that in the damping of equilibrium point be positive condition;

D2, to step D1 obtain arbitrary operating point in the bottom surface D of energy stabilization territory, determined the Transient Instability energy threshold E1 of this operating point by direct method, described Transient Instability energy threshold E1 meets the condition that transient state energy accumulation is no more than the max-thresholds that system can be born;

D3, operating point in step D2 is applied within the scope of 0-E1 to the disturbance of different-energy size, ask for and make system damping after disturbance be the energy value of 0, remember that this energy value is E2, E2 meets after disturbance in first cycle, the damping capacity that generator armature reaction produces and the condition that the damping capacity sum that generator windings, mechanical damping produce is greater than zero;

D4, all operating points on traversal energy stabilization territory bottom surface D, repeat step D2 and D3, determine E1 and E2 that all operating points are corresponding, the end face S1 be made up of all E1 is relevant to power system transient stability, if disturbance energy is higher than this end face, system is by Transient Instability, if disturbance energy is lower than this end face, system will keep transient stability, the end face that the end face S2 be made up of all E2 is formed is relevant with the dynamic stability in system oscillation process, if disturbance energy higher than S2 lower than S1, system incites somebody to action divergence instability gradually, if disturbance energy is lower than S2, system oscillation process will decay gradually,

D5, utilize the space that D surrounds, bottom surface, energy stabilization territory determined in the end face S2 and step D1 that determine in step D4 as energy stabilization territory.

In addition in step D1, utilize point by point method or protection mapping method determination energy stabilization territory bottom surface D.

By adopting electric system energy stabilization territory constructing system of the present invention and method, the dynamic equation that can launch the system that obtains at non-equilibrium some place solves damping capacity, on this basis, constructs a kind of novel comprehensive safety territory-energy stabilization territory.Electric system energy stabilization territory constructed by the present invention can reflect static stability and the dynamic stability of system, has higher accuracy.The electric system energy stabilization territory utilizing the present invention to be formed for guidance system management and running, learn system potential risk, formulate control program, ensure that security of system stable operation has beneficial effect.

Accompanying drawing explanation

Fig. 1 is electric system energy stabilization territory of the present invention constructing system structural representation.

The schematic diagram in the energy stabilization territory of Fig. 2 constructed by electric system energy stabilization territory constructing system of the present invention and method.

The IEEE4 machine two district system structural drawing of Fig. 3 for applying in one embodiment of the present invention.

The IEEE4 machine two district system parameter space Small Signal Stability Region schematic diagram of Fig. 4 for applying in one embodiment of the present invention.

Fig. 5 is determined energy stabilization territory in one embodiment of the present invention.

The IEEE4 machine two district system energy stabilization territory schematic cross-section of Fig. 6 for applying in one embodiment of the present invention.

Fig. 7 is the time-domain-simulation figure of point in the IEEE4 machine two district system energy stabilization territory cross section I section applied in one embodiment of the present invention and IV section.

The IEEE4 machine two district system energy stabilization territory cross section II section interior result in time domain figure that put of Fig. 8 for applying in one embodiment of the present invention.

The IEEE4 machine two district system energy stabilization territory cross section III section interior result in time domain figure that put of Fig. 9 for applying in one embodiment of the present invention.

Embodiment

Below in conjunction with accompanying drawing, the present invention is elaborated.

The example embodiment that following discloses are detailed.But concrete structure disclosed herein and function detail are only the objects for describing example embodiment.

But should be appreciated that, the present invention is not limited to disclosed concrete example embodiment, but covers all modifications, equivalent and the alternative that fall within the scope of the disclosure.In the description to whole accompanying drawing, identical Reference numeral represents identical element.

Should be appreciated that, term "and/or" as used in this comprises one or morely relevant lists any of item and all combinations simultaneously.Should be appreciated that in addition, when parts or unit are called as " connection " or " coupling " to another parts or unit, it can be directly connected or coupled to miscellaneous part or unit, or also can there is intermediate member or unit.In addition, other words being used for describing relation between parts or unit should be understood according to identical mode (such as, " between " to " directly ", " adjacent " to " direct neighbor " etc.).

In order to introduce technical scheme of the present invention, first principle of the present invention is described.

The model differential-algebraic equation group of electric system can be expressed as:

$\left\{\begin{array}{c}\stackrel{\·}{x}=f(x,y)\\ 0=g(x,y)\end{array}\right.---\left(1\right)$

In formula, x is quantity of state, and y is algebraic quantity.

The value of x and y at each integration step starting point place is obtained by analyzing.The x=x in this integration step is made at certain point k place _k+ Δ x, y=y _k, substitute into differential equation f (x, y), can obtain:

${\stackrel{\·}{x}}_k+{\mathrm{\Δ}\stackrel{\·}{x}}_k=f(x_k+{\mathrm{\Δx}}_k,y_k)---\left(2\right)$

By on the right side of formula (2) equation at (x _k, y _k) place carries out Taylor expansion:

$\begin{array}{c}{\stackrel{\·}{x}}_k+\mathrm{\Δ}{\stackrel{\·}{x}}_k=f(x_k+\mathrm{\Δ}{x}_k,y_k)\\ =f(x_k,y_k)+{\frac{\∂f}{\∂x}|}_k\mathrm{\Δx}+H.O.T.\end{array}---\left(3\right)$

As enough hour of Δ x, formula (3) can be ignored high-order term H.O.T. and obtain:

${\mathrm{\Δ}\stackrel{\·}{x}}_k=f(x_k,y_k)+A_k{\mathrm{\Δx}}_k---\left(4\right)$

In formula: $A_k={\frac{\∂f}{\∂x}|}_k.$

Formula (4) is done be out of shape as follows:

$\mathrm{\Δ}{\stackrel{\·}{x}}_k=A_k\mathrm{\Δ}{x}_k+A_k{A}_k^{-1}f(x_k,y_k)---\left(5\right)$

Make c=A _k ^-1f (x _k, y _k):

$\mathrm{\Δ}{\stackrel{\·}{x}}_k=A_k({\mathrm{\Δx}}_k+c)---\left(6\right)$

Formula (6) launches the system dynamic equation that obtains for system at non-equilibrium some place.

In addition, in one machine infinity bus system, the t generator amature equation of motion is as follows:

$\left\{\begin{array}{c}\stackrel{\·}{\mathrm{\δ}}\left(t\right)=\mathrm{\ω}\left(t\right)\\ T_J\stackrel{\·}{\mathrm{\ω}}\left(t\right)=P_m-P_e-D_M\mathrm{\ω}\left(t\right)\end{array}\right.---\left(7\right)$

Wherein, P _m, P _ebe respectively and act on epitrochanterian mechanical output and electromagnetic power, P _mto be exerted oneself decision by prime mover, and P _ecome from the interaction of the electromagnetic field that stator and rotor current produces in magnetic gap.D _mafter taking into account D winding, the damping action of Q winding in dynamic process and the mechanical damping in rotor motion, the permanent ratio of damping of introducing.

At [t _k, t _k+1] in time step, adopt second order Runge-Kutta method to calculate the oscillation energy injecting generator branch road by generator interior nodes to be:

$\begin{array}{c}{W}_k\≈-\mathrm{\Δ\δ}(P_{\mathrm{ek}}+\frac{1}{2}\mathrm{\Δ}{P}_{\mathrm{ek}})\\ =T_J\mathrm{\Δ\δ}({\stackrel{\·}{\mathrm{\ω}}}_k+\frac{1}{2}\mathrm{\Δ}{\stackrel{\·}{\mathrm{\ω}}}_k)-P_m\mathrm{\Δ\δ}\\ +D_M\mathrm{\Δ\δ}({\mathrm{\ω}}_k+\frac{1}{2}\mathrm{\Δ}{\mathrm{\ω}}_k)\end{array}---\left(8\right)$

The energy being injected generator branch road by network comprises two parts: one is the change of generator transient state energy, namely its two energy consumed for Generator Damping, namely

The electromagnetic power Δ P of the generator of expressing with Incremental Equation _ekcan be by Heffron-Phillips model representation:

ΔP _ek＝K _ekΔδ+D _ekΔω (9)

Wherein, K _ekand D _ekbe respectively t _kmoment generator synchronization factor and ratio of damping.The damping action size definition of each moment generator armature reaction to generator amature motion is the dynamic antivibration of generator by the present invention, and it is relevant with Δ ω item in electromagnetic power increment linear representation, in one machine infinity bus system, and D _ekbe dynamic antivibration.

Due to D _mperseverance be on the occasion of, in oscillatory process, only send positive damping capacity, to research because of negative damping energy produce Unstable oscillation process do not contact directly, for ease of analyze, generator adopts classical second-order model, makes D _m=0, now, the dynamic equation of system at non-equilibrium some k place is:

$\left[\begin{array}{c}\mathrm{\Δ\δ}\\ \mathrm{\Δ}\stackrel{\·}{\mathrm{\ω}}\end{array}\right]=\left[\begin{array}{cc}0& I\\ {{-T}_J}^{-1}{K}_{\mathrm{ek}}& {{-T}_J}^{-1}{D}_{\mathrm{ek}}\end{array}\right]\left[\begin{array}{c}\mathrm{\Δ\δ}+r_{\mathrm{\δk}}+{\mathrm{jv}}_{\mathrm{\δk}}\\ \mathrm{\Δ\ω}+r_{\mathrm{\ωk}}+{\mathrm{jv}}_{\mathrm{\ωk}}\end{array}\right]---\left(10\right)$

In formula:

$\left[\begin{array}{c}{r}_{\mathrm{\δk}}+{\mathrm{jv}}_{\mathrm{\δk}}\\ r_{\mathrm{\ωk}}+{\mathrm{jv}}_{\mathrm{\ωk}}\end{array}\right]={A_k}^{-1}\left[\begin{array}{c}{\stackrel{\·}{\mathrm{\δ}}}_k\\ {\stackrel{\·}{\mathrm{\ω}}}_k\end{array}\right]---\left(11\right)$

In formula (10), because the damping action of generator armature reaction to generator amature motion is only relevant with Δ ω, extract in this formula and can obtain with the synchronous part of Δ ω:

-T _JΔω＝K _ekv _δk+D _ek(Δω+r _ωk) (12)

Ask for No. i-th generator armature in system by formula (12) and react the damping capacity E accumulated in a cycle oscillatory process _difor:

$E_{\mathrm{Di}}=\underset{k=0}{\overset{T}{\mathrm{\Σ}}}\frac{1}{2}{\mathrm{\Δ\δ}}_i(K_{\mathrm{ek}}{v}_{\mathrm{\δk}}+D_{\mathrm{ek}}({\mathrm{\Δ\ω}}_i+r_{\mathrm{\ωk}}))---\left(13\right)$

Analysis mode (13) is known, certain generator damping capacity E after a failure in multi-computer system _diexcept the impact by other generator speeds in system, also relevant with the merit angle of other generators.After disturbance in system oscillation process, along with the difference of disturbance size, generator parameter K _ekand D _ekpositive and negative values ratio in a cycle also by difference, thus causes the positive negative variance of this machine damping capacity.If in first vibration cycle, the damping capacity that generator produces is negative, and in the motion of follow-up cycle, system incites somebody to action divergence instability gradually; If the damping capacity that generator produces in first vibration cycle is 0, in the motion of follow-up cycle, will there is continuous oscillation phenomenon in system; If the damping capacity that generator produces in first cycle is just, then system tends towards stability gradually by the motion of follow-up cycle.

Therefore, for judging whether a system is stablized under a certain disturbance or fault, only can not be judged by system balancing dotted state, jointly must determine in conjunction with disturbance size.In order to analyze different disturbance size intuitively to the impact of system stability comprehensively, the present invention will build electric system energy stabilization territory at parameter-energy space, for system stability after disturbance judges to provide an instrument fast and accurately.

Energy stabilization territory is defined in all of parameter-energy space can ensure that system keeps the operating point-disturbance energy of dynamic stability to set after disturbance.Electric system can 3 conditions below safe and stable operation demand fulfillment under disturbance:

Condition 1: system must ensure that under current operating condition in the damping of equilibrium point be just, for negative, Unstable oscillation phenomenon can not occur to guarantee system to have certain stability margin when bearing certain disturbance because of damping.

Condition 2: after disturbance in first cycle, the damping capacity that generator armature reaction produces and the damping capacity sum that produces of generator windings, mechanical damping are greater than 0, to guarantee power system dynamic stability after disturbance.

Condition 3: the transient state energy accumulation that fault causes is no more than the max-thresholds that system can be born, to guarantee that Transient Instability problem can not occur system.

Therefore, Fig. 1 is electric system energy stabilization territory of the present invention constructing system structural representation.As shown in Figure 1, in embodiment of the present invention electric system energy stabilization territory constructing system comprise connect successively data acquisition module, system dynamic equation generation module, damping capacity solve module, energy stabilization territory builds module and result output module; Wherein, data acquisition module is used for generator frequency, merit angle in collection network structural parameters, system, and image data is sent to system dynamic equation generation module; The dynamic equation of system dynamic equation generation module for utilizing the data of reading in system to be launched the system that obtains at non-equilibrium some place; Damping capacity solves module and reacts for asking for generator armature in system the damping capacity accumulated in a cycle oscillatory process; Energy stabilization territory builds module for the power system dynamic stability criterion according to disturbance size and system state, builds the electric system energy stabilization territory of reflection system dynamic stability and transient stability; Result output module is used for output power system capacity stable region.

Especially, in the specific embodiment of the invention, the system dynamic equation that system dynamic equation generation module obtains is:

$\mathrm{\Δ}{\stackrel{\·}{x}}_k=A_k({\mathrm{\Δx}}_k+c),$

Wherein, c=A _k ^-1f (x _k, y _k),

$A_k={\frac{\∂f}{\∂x}|}_k,$

${\stackrel{\·}{x}}_k=f(x_k,y_k),$

X _kand y _kbe respectively quantity of state and the algebraic quantity of point k place system.

In addition, in the embodiment of the invention, damping capacity solves the damping capacity that module asks for and is:

$E_{\mathrm{Di}}=\underset{k=0}{\overset{T}{\mathrm{\Σ}}}\frac{1}{2}{\mathrm{\Δ\δ}}_i(K_{\mathrm{ek}}{v}_{\mathrm{\δk}}+D_{\mathrm{ek}}({\mathrm{\Δ\ω}}_i+r_{\mathrm{\ωk}})),$

Wherein, $\left[\begin{array}{c}{r}_{\mathrm{\δk}}+{\mathrm{jv}}_{\mathrm{\δk}}\\ r_{\mathrm{\ωk}}+{\mathrm{jv}}_{\mathrm{\ωk}}\end{array}\right]={A_k}^{-1}\left[\begin{array}{c}{\stackrel{\·}{\mathrm{\δ}}}_k\\ {\stackrel{\·}{\mathrm{\ω}}}_k\end{array}\right],$

Δ δ _i, Δ ω _ibe respectively i-th generator's power and angle variable quantity and rotation speed change amount,

K _ekand D _ekbe respectively t _kmoment generator synchronization factor and ratio of damping.

The present invention also comprises a kind of electric system energy stabilization territory construction method, and described method comprises step:

Generator frequency, merit angle in A, collection time lag system network architecture parameters, system;

System is launched the dynamic equation of the system that obtains by the data that B, utilization gather at non-equilibrium some place;

C, ask for generator armature in system and react the damping capacity accumulated in a cycle oscillatory process;

D, power system dynamic stability criterion according to disturbance size and system state, build the electric system energy stabilization territory of reflection system dynamic stability and transient stability;

E, export described electric system energy stabilization territory.

Correspondingly, the system dynamic equation obtained in step B is:

$\mathrm{\Δ}{\stackrel{\·}{x}}_k=A_k({\mathrm{\Δx}}_k+c),$

Wherein, c=A _k ^-1f (x _k, y _k),

$A_k={\frac{\∂f}{\∂x}|}_k,$

${\stackrel{\·}{x}}_k=f(x_k,y_k),$

X _kand y _kbe respectively quantity of state and the algebraic quantity of point k place system.

In addition, the damping capacity obtained in step C is:

$E_{\mathrm{Di}}=\underset{k=0}{\overset{T}{\mathrm{\Σ}}}\frac{1}{2}{\mathrm{\Δ\δ}}_i(K_{\mathrm{ek}}{v}_{\mathrm{\δk}}+D_{\mathrm{ek}}({\mathrm{\Δ\ω}}_i+r_{\mathrm{\ωk}})),$

Wherein, $\left[\begin{array}{c}{r}_{\mathrm{\δk}}+{\mathrm{jv}}_{\mathrm{\δk}}\\ r_{\mathrm{\ωk}}+{\mathrm{jv}}_{\mathrm{\ωk}}\end{array}\right]={A_k}^{-1}\left[\begin{array}{c}{\stackrel{\·}{\mathrm{\δ}}}_k\\ {\stackrel{\·}{\mathrm{\ω}}}_k\end{array}\right],$

Δ δ _i, Δ ω _ibe respectively i-th generator's power and angle and rotation speed change amount,

K _ekand D _ekbe respectively t _kmoment generator synchronization factor and ratio of damping.

With analyze above corresponding, it is characterized in that the power system dynamic stability criterion of disturbance size and system state in step D comprises:

System ensures that under current operating condition in the damping of equilibrium point be just;

After disturbance in first cycle, the damping capacity that generator armature reaction produces and the damping capacity sum that generator windings, mechanical damping produce are greater than zero;

The transient state energy accumulation that fault causes is no more than the max-thresholds that system can be born.

Correspondingly, determine in step D that electric system energy stabilization territory comprises:

D1, adopt Small Signal Stability Region method for solving determination energy stabilization territory bottom surface D at parameter space, described energy stabilization territory bottom surface D meets system under current operating condition, ensures that in the damping of equilibrium point be positive condition;

D2, to step D1 obtain arbitrary operating point in the bottom surface D of energy stabilization territory, determined the Transient Instability energy threshold E1 of this operating point by direct method, described Transient Instability energy threshold E1 meets the condition that transient state energy accumulation is no more than the max-thresholds that system can be born;

D3, operating point in step D2 is applied within the scope of 0-E1 to the disturbance of different-energy size, ask for and make system damping after disturbance be the energy value of 0, remember that this energy value is E2, E2 meets after disturbance in first cycle, the damping capacity that generator armature reaction produces and the condition that the damping capacity sum that generator windings, mechanical damping produce is greater than zero;

All operating points on D4, traversal energy stabilization territory bottom surface D, repeat step D2-D3, determine E1 and E2 that all operating points are corresponding.The schematic diagram in the energy stabilization territory of Fig. 2 constructed by electric system energy stabilization territory constructing system of the present invention and method, as shown in Figure 2, the end face S1 be made up of all E1 is relevant to power system transient stability, if disturbance energy is higher than this end face, system is by Transient Instability, if disturbance energy is lower than this end face, system will keep transient stability, the end face that the end face S2 be made up of all E2 is formed is relevant with the dynamic stability in system oscillation process, if disturbance energy higher than S2 lower than S1, system incites somebody to action divergence instability gradually, if disturbance energy is lower than S2, system oscillation process will decay gradually,

D5, utilize the space that D surrounds, bottom surface, energy stabilization territory determined in the end face S2 and step D1 that determine in step D4 as energy stabilization territory.

Especially, in an embodiment, in step D1, utilize point by point method or protection mapping method determination energy stabilization territory bottom surface D.

Next by concrete application example, technique effect of the present invention is described.

First IEEE4 machine two district system is as shown in Figure 3 built, with it for analysis foundation.

In system, generator adopts six rank transient Model.Utilize and select model analysis (Selective mode analysis, SMA) method to carry out depression of order to high order system, in the process of depression of order, retain relevant to low-frequency oscillation and be easy to the quantity of state measured.Excitation system adopts high-speed excitation, and the load under benchmark model adopts the constant-impedance of 50% and the continuous current mixture model of 50%.

No. 1 generator energy stable region is set up according to electric system energy stabilization territory of the present invention construction method.

Step 1: with on bus 4 and 14 band burden with power P4 and P14 for parametric variable, utilize protection mapping method to ask for system equilibrium point damping on this parameter space and be greater than the border of 0 as stable region bottom surface, as shown in Figure 4.

Step 2: to the operating point in stable region bottom surface required by step 1, determined the Transient Instability energy threshold of this operating point by direct method, remember that this energy is E1.So that in stable region bottom surface required by step 1, (-0.25,0.25) point is for example, utilizing direct method to obtain this Transient Instability energy is 0.60MW*S, as shown in Figure 5.

Step 3: the disturbance this operating point being applied within the scope of 0-E1 to different-energy size, finds according to formula (13) and makes system damping capacity after disturbance be the value of 0, remember that this energy is E2.With in stable region bottom surface required by step 1 (-0.25,0.25) be example, different disturbance energies between 0-0.60MW*S are applied to system, utilize formula (13) to ask for after disturbance Generator Damping energy size in the first cycle, if damping capacity is less than 0, then reduce initial disturbance energy, if damping capacity is greater than 0, then increase initial disturbance energy, until hunt out the initial disturbance energy value that damping capacity is 0, acquired results is 0.53MW*S.

Step 4: to all operating points on stable region bottom surface required in step 1, with 0.05 for step-length travels through, repeat step 2-3, ask for E1 and E2 that all operating points are corresponding respectively, as shown in the figure of Fig. 6 middle section.

Step 5: get E2 form space that in the end face of energy and step 1, stable region bottom surface surrounds as energy stabilization territory.

In order to verify the correctness in constructed energy stabilization territory further, analysis verification is carried out to the point inside and outside stable region.

With P14=-0.25 cross section for analytic target, as shown in Figure 6.Wherein, P4 is divided into 4 sections by-1.5 to 1, be respectively I section ([-1.5,-0.75]), II section ([-0.75,-0.05]), III section ([-0.05,0.5]), IV section ([0.5,1]), and in III section, end face shown in E2, E1 to be drawn respectively.In II section, end face shown in E2, E1 overlaps.

To A in I section in Fig. 6 _ia in point (-0.25 ,-1,0.1) and section _iV(-0.25,0.6,0.1) point emulates respectively, and result as shown in Figure 7.What reflect in Fig. 7 is generator 1 and generator 3 merit angular difference situation over time.As can be seen from the figure, system is diverging oscillation because of underdamping, and now, system works, at unsafe condition, is therefore got rid of outside energy stabilization territory.

To A in II section in Fig. 6 _iIpoint (-0.25 ,-0.4,0.3) and B _iIpoint (-0.25 ,-0.4,0.4) emulates respectively, and result as shown in Figure 8.What reflect in figure is the merit angular difference situation over time of generator 1 and generator 3.As can be seen from the figure, when system is in A in II section _iIduring dotted state, after there is disturbance, in oscillatory process, damping capacity is just, the merit angular difference of generator 1 and generator 3 tends towards stability, gradually as shown in Fig. 8 (a).And when system is positioned at III section B _iIduring dotted state, because oscillation energy exceedes Transient Instability threshold value, after disturbance occurs, system is by direct Transient Instability, as shown in Fig. 8 (b).

To A in III section in Fig. 6 _iIIpoint (-0.25,0.25,0.48), B _iIIpoint (-0.25,0.25,0.0.53), C _iIIpoint (-0.25,0.25,0.58), D _iIIpoint (-0.25,0.25,0.63) emulates respectively, and result as shown in Figure 9.What reflect in figure is generator 1 and generator 3 merit angular difference situation over time.

As seen from Figure 9, when system is in A in III section _iIIduring dotted state, after there is disturbance, in oscillatory process, damping capacity is just, the merit angular difference of generator 1 and generator 3 tends towards stability, gradually as shown in Fig. 9 (a).And be positioned at III section B _iIIafter disturbance occurs point, in oscillatory process, damping capacity is just 0, and constant amplitude persistent oscillation occurs the merit angle between generator 1 and generator 3, as shown in Fig. 9 (b).When system running state is in C in III section _iIIduring point, after there is disturbance, in oscillatory process, damping capacity is for negative and oscillation energy is no more than Transient Instability threshold value, system is because damping capacity is for bearing ever-diverging oscillations, although system is unlikely to unstability in the short time, but this process lasts goes down final initiating system Transient Instability, as shown in Fig. 9 (c).When system running state is positioned at III section D _iIIduring point, because oscillation energy exceedes Transient Instability threshold value, after disturbance occurs, system is by direct Transient Instability, as shown in Fig. 9 (d).

It can thus be appreciated that, utilize the system capacity stable region constructed by the present invention to have higher accuracy.

It should be noted that; above-mentioned embodiment is only the present invention's preferably embodiment; the restriction to distance protection scope of the present invention can not be understood as, not depart under concept thereof of the present invention, with modification, distance protection scope of the present invention is all belonged to any subtle change that the present invention does.

Claims (9)

1. an electric system energy stabilization territory constructing system, described system comprise connect successively data acquisition module, system dynamic equation generation module, damping capacity solve module, energy stabilization territory builds module and result output module;

Wherein, data acquisition module is used for generator frequency, merit angle in collection network structural parameters, system, and image data is sent to system dynamic equation generation module;

The dynamic equation of system dynamic equation generation module for utilizing the data of reading in system to be launched the system that obtains at non-equilibrium some place;

Damping capacity solves module and reacts for asking for generator armature in system the damping capacity accumulated in a cycle oscillatory process;

Energy stabilization territory builds module for the power system dynamic stability criterion according to disturbance size and system state, builds the electric system energy stabilization territory of reflection system dynamic stability and transient stability;

Result output module is used for output power system capacity stable region.

2. according to the electric system energy stabilization territory constructing system described in claim 1, it is characterized in that, the system dynamic equation that system dynamic equation generation module obtains is:

$\mathrm{\Δ}{\stackrel{\·}{x}}_k=A_k({\mathrm{\Δx}}_k+c),$

Wherein, c=A _k ^-1f (x _k, y _k),

$A_k=\frac{\∂f}{\∂x}{|}_k,$

${\stackrel{\·}{x}}_k=f(x_k,y_k),$

X _kand y _kbe respectively quantity of state and the algebraic quantity of point k place system, Δ x _kfor x _kknots modification.

3. according to the electric system energy stabilization territory constructing system described in claim 2, it is characterized in that, damping capacity solves the damping capacity that module asks for and is:

$E_{\mathrm{Di}}=\underset{k=0}{\overset{T}{\mathrm{\Σ}}}\frac{1}{2}{\mathrm{\Δ\δ}}_i(K_{\mathrm{ek}}{v}_{\mathrm{\δk}}+D_{\mathrm{ek}}({\mathrm{\Δ\ω}}_i+r_{\mathrm{\ωk}})),$

Wherein, $\left[\begin{array}{c}{r}_{\mathrm{\δk}}+{\mathrm{jv}}_{\mathrm{\δk}}\\ r_{\mathrm{\ωk}}+{\mathrm{jv}}_{\mathrm{\ωk}}\end{array}\right]={A_k}^{-1}\left[\begin{array}{c}{\stackrel{\·}{\mathrm{\δ}}}_k\\ {\stackrel{\·}{\mathrm{\ω}}}_k\end{array}\right],$

Δ δ _i, Δ ω _ibe respectively i-th generator's power and angle variable quantity and rotation speed change amount,

K _ekand D _ekbe respectively t _kmoment generator synchronization factor and ratio of damping.

4. an electric system energy stabilization territory construction method, described method comprises step:

Generator frequency, merit angle in A, collection time lag system network architecture parameters, system;

System is launched the dynamic equation of the system that obtains by the data that B, utilization gather at non-equilibrium some place;

C, ask for generator armature in system and react the damping capacity accumulated in a cycle oscillatory process;

D, power system dynamic stability criterion according to disturbance size and system state, build the electric system energy stabilization territory of reflection system dynamic stability and transient stability;

E, export described electric system energy stabilization territory.

5., according to the electric system energy stabilization territory construction method described in claim 4, it is characterized in that the system dynamic equation obtained in step B is:

$\mathrm{\Δ}{\stackrel{\·}{x}}_k=A_k({\mathrm{\Δx}}_k+c),$

Wherein, c=A _k ^-1f (x _k, y _k),

$A_k=\frac{\∂f}{\∂x}{|}_k,$

${\stackrel{\·}{x}}_k=f(x_k,y_k),$

X _kand y _kbe respectively quantity of state and the algebraic quantity of point k place system, Δ x _kfor x _kknots modification.

6., according to the electric system energy stabilization territory construction method described in claim 4, it is characterized in that the damping capacity obtained in step C is:

$E_{\mathrm{Di}}=\underset{k=0}{\overset{T}{\mathrm{\Σ}}}\frac{1}{2}{\mathrm{\Δ\δ}}_i(K_{\mathrm{ek}}{v}_{\mathrm{\δk}}+D_{\mathrm{ek}}({\mathrm{\Δ\ω}}_i+r_{\mathrm{\ωk}})),$

Wherein, $\left[\begin{array}{c}{r}_{\mathrm{\δk}}+{\mathrm{jv}}_{\mathrm{\δk}}\\ r_{\mathrm{\ωk}}+{\mathrm{jv}}_{\mathrm{\ωk}}\end{array}\right]={A_k}^{-1}\left[\begin{array}{c}{\stackrel{\·}{\mathrm{\δ}}}_k\\ {\stackrel{\·}{\mathrm{\ω}}}_k\end{array}\right],$

Δ δ _i, Δ ω _ibe respectively i-th generator's power and angle and rotation speed change amount,

K _ekand D _ekbe respectively t _kmoment generator synchronization factor and ratio of damping.

7., according to the electric system energy stabilization territory construction method described in claim 4, it is characterized in that the power system dynamic stability criterion of disturbance size and system state in step D comprises:

System ensures that under current operating condition in the damping of equilibrium point be just;

After disturbance in first cycle, the damping capacity that generator armature reaction produces and the damping capacity sum that generator windings, mechanical damping produce are greater than zero;

The transient state energy accumulation that fault causes is no more than the max-thresholds that system can be born.

8., according to the electric system energy stabilization territory construction method described in claim 7, it is characterized in that in step D, determining that electric system energy stabilization territory comprises:

D1, adopt Small Signal Stability Region method for solving determination energy stabilization territory bottom surface D at parameter space, described energy stabilization territory bottom surface D meets system under current operating condition, ensures that in the damping of equilibrium point be positive condition;

D2, to step D1 obtain arbitrary operating point in the bottom surface D of energy stabilization territory, determined the Transient Instability energy threshold E1 of this operating point by direct method, described Transient Instability energy threshold E1 meets the condition that transient state energy accumulation is no more than the max-thresholds that system can be born;

D3, operating point in step D2 is applied within the scope of 0-E1 to the disturbance of different-energy size, ask for and make system damping after disturbance be the energy value of 0, remember that this energy value is E2, E2 meets after disturbance in first cycle, the damping capacity that generator armature reaction produces and the condition that the damping capacity sum that generator windings, mechanical damping produce is greater than zero;

D4, all operating points on traversal energy stabilization territory bottom surface D, repeat step D2 and D3, determine E1 and E2 that all operating points are corresponding, the end face S1 be made up of all E1 is relevant to power system transient stability, if disturbance energy is higher than this end face, system is by Transient Instability, if disturbance energy is lower than this end face, system will keep transient stability, the end face that the end face S2 be made up of all E2 is formed is relevant with the dynamic stability in system oscillation process, if disturbance energy higher than S2 lower than S1, system incites somebody to action divergence instability gradually, if disturbance energy is lower than S2, system oscillation process will decay gradually,

D5, utilize the space that D surrounds, bottom surface, energy stabilization territory determined in the end face S2 and step D1 that determine in step D4 as energy stabilization territory.

9. according to Claim 8 described in electric system energy stabilization territory construction method, it is characterized in that in step D1, utilize point by point method or protection mapping method determination energy stabilization territory bottom surface D.