CN103475010B - Transient stabilization control method for interconnection electrical network after impact disturbance - Google Patents

Abstract

The invention provides a transient stabilization control method for an interconnection electrical network after impact disturbance. The method comprises: based on the transient energy function of the electrical network after the impact disturbance, establishing, according to the energy propagation characteristic of the power fluctuation of a junctor, a junctor cut set potential energy function; through a junctor cut set potential energy curve and the angular phase difference of the busbars at the two ends of the junctor, predicting the angular phase stability of the interconnection electrical network; and calculating the power for removing a unit when there is power angle instability. The method provided by the invention can be applied to the theoretically and simulation analysis of an electric power system. By using the method, the propagation characteristics of transient energy in the electrical network after the impact disturbance can be mastered, the stability of the interconnection electrical network can be predicted, and a controlled variable for maintaining stability can be calculated, thus effective measures can be taken by analysis personnel, and the safe and stable operation level of the electric power system can be improved.

Description

A kind of Transient Stability Control method of interconnected network after shock vibration

Technical field

The invention belongs to technical field of power systems, be specifically related to the Transient Stability Control method of interconnected network after a kind of shock vibration.

Background technology

Along with the increase of degree interconnected between regional power grid, especially the putting into operation of Changzhi ~ Nanyang ~ Jingmen UHV demonstration project, makes the trans-regional interconnected network that China's electrical network becomes the biggest in the world.After shock vibration occurs, usually on interconnection, produce power fluctuation, when shock vibration acquires a certain degree, merit angle step-out will be there is at interconnection transmission cross-section place, cause system merit angle unstability, especially ultra high voltage interconnection can produce substantial power fluctuation, and become transmission cross-section the weakest in electrical network, not only have impact on the maintenance level of North China-Central China interconnected network, limit the raising of ultra high voltage interconnection ability to transmit electricity, have impact on extra high voltage line and give full play to its Social and economic benef@of transmitting electricity on a large scale.

The precautionary measures occurred for shock vibration in current electrical network are restriction interconnection transmission powers, carry out a large amount of n-1 and calculate, and guarantee system can ensure the stability of system after shock vibration occurs.In actual motion, traditional control method is mainly based on the method for calculated off-line Policy Table, On-line matching, but this prediction scheme type control scheme list can not take into account all fault modes of electrical network, the modern power network position of fault and the time changeable, the order of severity is not identical yet, easily because control strategy do not mate cause system unstability or control excessive.Therefore need study forecasting type based on the real-time Transient Stability Control method in line computation.For in the transient stability real-time control method of interconnected network shock vibration, there is not yet relevant report both at home and abroad at present.

Summary of the invention

In order to overcome above-mentioned the deficiencies in the prior art, the invention provides the Transient Stability Control method of interconnected network after a kind of shock vibration, based on the transient energy function of electrical network after shock vibration, according to the energy propagation characteristics of interconnection tie power fluctuation, set up interconnection cut set potential-energy function, by interconnection cut set potential energy curve and interconnection two ends bus phase angle difference, the power-angle stability of prediction interconnected network, calculates the power of excision unit when there is merit angle unstability.The present invention can apply to theory and the simulation analysis of electric power system, the propagation characteristic of transient state energy in electrical network after grasp shock vibration, the stability of prediction interconnected network, calculate and keep stable controlled quentity controlled variable, be beneficial to system cloud gray model, analyst takes effective measures in time, improve the safe and stable operation level of electric power system.

In order to realize foregoing invention object, the present invention takes following technical scheme:

The Transient Stability Control method of interconnected network after a kind of shock vibration is provided, said method comprising the steps of:

Step 1: after shock vibration occurs, interconnected network enters transient process, based on transient energy function method, according to the tie-line power transmission gathered in interconnected network and two ends phase angle difference, calculate the transient potential energy of this interconnection cut set, make this interconnection potential energy curve of cyclical fluctuations in time;

Step 2: according to the interconnection two ends bus phase angle difference gathered, calculates interconnection phase angle change rate, makes phase angle change rate curve;

Step 3: judge whether interconnected network occurs merit angle unstability according to interconnected network angle stability prognostic criteria, if so, then start the calculating of Transient Stability Control strategy, control object is sending generator; If not, then show that interconnected network can keep stable at next pendulum;

Step 4: determine the power excising unit according to the calculating of Transient Stability Control strategy, and return step 3 continuation execution, until merit angle unstability does not appear in interconnected network.

In described step 1, transient energy function have employed the structure-preserved topological Liapunov function model of the multimachine system ignoring damping:

$V=V_{\mathrm{KE}}+V_{\mathrm{PE}}=\frac{1}{2}\underset{g=1}{\overset{m}{\mathrm{\Σ}}}{M}_g{\mathrm{\ω}}_g^2+\underset{a=1}{\overset{l}{\mathrm{\Σ}}}{\∫}_{{\mathrm{\σ}}_a^s}^{{\mathrm{\σ}}_a}[P_a\left(u\right)-P_a^s]\mathrm{du}---\left(1\right)$

Wherein, V is the gross energy of interconnected network, V _kEfor the total kinetic energy of interconnected network, V _pEfor total potential energy of interconnected network, m is total number of units of generator, M _git is the moment of inertia of g platform generator; ω _gbe the angular speed of g platform generator, l is the branch road sum of interconnected network, σ _awith be respectively the phase angle difference of a article of branch road and a article of branch road phase angle difference after a failure under poised state; P _a(u) and be respectively the effective power flow of a article of branch road and a article of branch road relative to the effective power flow under post-fault equilibrium state;

If be a unit by each Coherent Generator Group equivalence, then in formula (1), the transient state energy of interconnected network only can consider the transient state energy of interconnection transmission cross-section; If each transmission cross-section is the separation of an interconnected network pass through cut set, if cut set C is passed through in i-th of interconnected network separation _ihave q loop line road, then after fault, the cut set energy of interconnected network is expressed as:

$V_{\mathrm{Cut}}=\frac{1}{2}\frac{M_A{M}_B}{M_A+M_B}{({\widetilde{\mathrm{\ω}}}_A+{\widetilde{\mathrm{\ω}}}_B)}^2+\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{{\mathrm{\σ}}_k^0}^{{\mathrm{\σ}}_k}(P_k\left(u\right)-P_k^0)\mathrm{du}---\left(2\right)$

Wherein, V _cutfor the cut set energy of interconnected network after fault, with be respectively the center of inertia angular speed of people having the same aspiration and interest unit A and people having the same aspiration and interest B of Unit, σ _kwith be respectively the phase angle difference of the kth bar interconnection when the stable equilibrium point of interconnected network after the phase angle difference of kth bar interconnection and fault; P _k(u) and be respectively the effective power flow of kth bar interconnection and kth bar branch road relative to the effective power flow under post-fault equilibrium state; Q is that cut set C is passed through in separation _iinterconnector number;

The transient potential energy obtaining interconnection cut set according to formula (2) is:

$V_{\mathrm{PEtie}}\left(t\right)=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_s}^t[P_k\left(t\right)-P_k^0]\frac{\mathrm{du}}{\mathrm{dt}}\mathrm{dt}---\left(3\right)$

Wherein, V _pEtiet () is the transient potential energy of interconnection cut set, P _kt () to be gained merit time dependent function for branch road, t _sfor fault reaches the moment of post-fault equilibrium point, for branch road phase angle difference is to the derivative of time;

The moment reaching stable equilibrium point due to interconnected network after fault can only get estimated value according to failure condition, and therefore the transient potential energy of interconnection cut set is the Branch Potential Energy sum of transmission cross-section, and formula (3) can be written as:

$V_{\mathrm{PEtie}}\left(t\right)=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_c}^t[P_k\left(t\right)-P_k^0]\frac{\mathrm{du}}{\mathrm{dt}}\mathrm{dt}+V_{\mathrm{PEtie}}\left(t_c\right)---\left(4\right)$

Wherein, t _crepresent the failure removal moment, V _pEtie(t _c) be:

$V_{\mathrm{PEtie}}\left(t_c\right)=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_s}^{t_c}[P_k\left(t\right)-P_k^0]\frac{\mathrm{du}}{\mathrm{dt}}\mathrm{dt}---\left(5\right)$

Wherein, V _pEtie(t _c) for kth bar interconnection is from the failure removal moment to the cut set potential energy increment fault stable state.

Interconnection phase angle change rate in described step 2 calculates according to Real-time Collection amount σ (t) of interconnection two ends bus phase angle difference, and its expression formula is:

${\mathrm{\ω}}_{\mathrm{tie}}\left(t\right)=\frac{\mathrm{d\σ}\left(t\right)}{\mathrm{dt}}---\left(6\right)$

Wherein, ω _tiet () is interconnection phase angle change rate, it is as the reference quantity of interconnected network angle stability prognostic criteria.

Interconnected network angle stability prognostic criteria in described step 3 is:

$V_{\mathrm{PEtie}}\left(t\right)=V_{\mathrm{PEtie}\max }\left\{\begin{array}{cc}{\mathrm{\ω}}_{\mathrm{tie}}\left(t\right)=0& \mathrm{St}=1\\ {\mathrm{\ω}}_{\mathrm{tie}}\left(t\right)\≠0& \mathrm{St}=0\end{array}\right.---\left(7\right)$

Wherein, V _pEtiemaxfor the transient potential energy extreme value of interconnection cut set; When St is 1, predicts interconnected network and can keep stable at next pendulum; When St is 0, predicts interconnected network and occur merit angle unstability.

There is merit angle unstability in interconnected network, start the calculating of Transient Stability Control strategy, control object is sending generator;

Calculate failure removal moment interconnected network potential energy, the potential energy of Branch Potential Energy kth interconnected network when time to reach extreme value and failure removal moment interconnected network kinetic energy, specifically have:

$V_2=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_0}^{t_c}\mathrm{\Δ}{P}_{\mathrm{tiek}}\left(t\right){\mathrm{\ω}}_{\mathrm{tiek}}\left(t\right)\mathrm{dt}---\left(8\right)$

$V_3=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_0}^{t_{\mathrm{bk}}}\mathrm{\Δ}{P}_{\mathrm{tiek}}\left(t\right){\mathrm{\ω}}_{\mathrm{tiek}}\left(t\right)\mathrm{dt}---\left(9\right)$

$W_2=\frac{1}{2}{M}_q{\widetilde{\mathrm{\ω}}}_q^2---\left(10\right)$

Wherein, V ₂for failure removal moment interconnected network potential energy, V ₃the potential energy of interconnected network during extreme value is reached, W for Branch Potential Energy kth is secondary ₂for failure removal moment interconnected network kinetic energy.

T ₀for fault moment, t _cfor the failure removal moment, t _bkfor Branch Potential Energy kth time reaches the moment of extreme value, Δ P _tiekt () is the power fluctuation value of kth bar interconnection, ω _tiekt () is kth bar interconnection line phase angle change rate, M _qfor equivalent moment of inertia, for center of inertia angular speed.

In described step 4, if t _bkwhen moment Branch Potential Energy kth time reaches extreme value, the kinetic energy of interconnected network is W ₃, excising unit energy when merit angle unstability appears in interconnected network is Δ W _c;

Have according to law of conservation of energy:

V ₂+W ₂=V ₃+W ₃（11）

Excision generated energy Δ W _cfor:

ΔW _c=W ₃=W ₂+V ₂-V ₃（12）

So the power of excision unit is:

$\mathrm{\Δ}{P}_c=\frac{2\mathrm{\Δ}{W}_C}{T_J}---\left(13\right)$

Wherein, Δ P _cfor excising the power of unit.

Compared with prior art, beneficial effect of the present invention is: the transient energy function that the present invention is based on electrical network after shock vibration, according to the energy propagation characteristics of interconnection tie power fluctuation, set up interconnection cut set potential-energy function, by interconnection cut set potential energy curve and interconnection two ends phase angle difference change rate curve, the power-angle stability of prediction interconnected network, calculates the power of excision unit when there is merit angle unstability.The present invention can apply to theory and the simulation analysis of electric power system, the propagation characteristic of transient state energy in electrical network after grasp shock vibration, the stability of prediction interconnected network, calculate and keep stable controlled quentity controlled variable, be beneficial to system cloud gray model, analyst takes effective measures in time, improve the safe and stable operation level of electric power system.

Accompanying drawing explanation

Fig. 1 is the Transient Stability Control method flow diagram of interconnected network after shock vibration in the embodiment of the present invention;

Fig. 2 is North China-Central China power-angle curve figure after the impulse fault of different location in the embodiment of the present invention;

Fig. 3 is bus voltage curve after the impulse fault of different location in the embodiment of the present invention;

Fig. 4 is UHV transmission power after the impulse fault of different location in the embodiment of the present invention;

Fig. 5 is ultra high voltage cut set potential energy, phase angle change rate, phase angle and transmitted power curve chart when prognoses system is stablized in the embodiment of the present invention;

Ultra high voltage cut set potential energy, phase angle change rate, phase angle and transmitted power curve chart when Fig. 6 is prognoses system unstability in the embodiment of the present invention;

Fig. 7 adopts ultra high voltage busbar voltage curve chart after stability contorting measure in the embodiment of the present invention.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in further detail.

As Fig. 1, the invention provides the Transient Stability Control method of interconnected network after a kind of shock vibration, said method comprising the steps of:

Step 1: after shock vibration occurs, interconnected network enters transient process, based on transient energy function method, according to the tie-line power transmission gathered in interconnected network and two ends phase angle difference, calculate the transient potential energy of this interconnection cut set, make this interconnection potential energy curve of cyclical fluctuations in time;

Step 2: according to the interconnection two ends bus phase angle difference gathered, calculates interconnection phase angle change rate, makes phase angle change rate curve;

Step 3: judge whether interconnected network occurs merit angle unstability according to interconnected network angle stability prognostic criteria, if so, then start the calculating of Transient Stability Control strategy, control object is sending generator; If not, then show that interconnected network can keep stable at next pendulum;

Step 4: determine the power excising unit according to the calculating of Transient Stability Control strategy, and return step 3 continuation execution, until merit angle unstability does not appear in interconnected network.

In described step 1, transient energy function have employed the structure-preserved topological Liapunov function model of the multimachine system ignoring damping:

$V=V_{\mathrm{KE}}+V_{\mathrm{PE}}=\frac{1}{2}\underset{g=1}{\overset{m}{\mathrm{\Σ}}}{M}_g{\mathrm{\ω}}_g^2+\underset{a=1}{\overset{l}{\mathrm{\Σ}}}{\∫}_{{\mathrm{\σ}}_a^s}^{{\mathrm{\σ}}_a}[P_a\left(u\right)-P_a^s]\mathrm{du}---\left(1\right)$

Wherein, V is the gross energy of interconnected network, V _kEfor the total kinetic energy of interconnected network, V _pEfor total potential energy of interconnected network, m is total number of units of generator, M _git is the moment of inertia of g platform generator; ω _gbe the angular speed of g platform generator, l is the branch road sum of interconnected network, σ _awith be respectively the phase angle difference of a article of branch road and a article of branch road phase angle difference after a failure under poised state; P _a(u) and be respectively the effective power flow of a article of branch road and a article of branch road relative to the effective power flow under post-fault equilibrium state;

If be a unit by each Coherent Generator Group equivalence, then in formula (1), the transient state energy of interconnected network only can consider the transient state energy of interconnection transmission cross-section; If each transmission cross-section is the separation of an interconnected network pass through cut set, if cut set C is passed through in i-th of interconnected network separation _ihave q loop line road, then after fault, the cut set energy of interconnected network is expressed as:

$V_{\mathrm{Cut}}=\frac{1}{2}\frac{M_A{M}_B}{M_A+M_B}{({\widetilde{\mathrm{\ω}}}_A+{\widetilde{\mathrm{\ω}}}_B)}^2+\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{{\mathrm{\σ}}_k^0}^{{\mathrm{\σ}}_k}(P_k\left(u\right)-P_k^0)\mathrm{du}---\left(2\right)$

Wherein, V _cutfor the cut set energy of interconnected network after fault, with be respectively the center of inertia angular speed of people having the same aspiration and interest unit A and people having the same aspiration and interest B of Unit, σ _kwith be respectively the phase angle difference of the kth bar interconnection when the stable equilibrium point of interconnected network after the phase angle difference of kth bar interconnection and fault; P _k(u) and be respectively the effective power flow of kth bar interconnection and kth bar branch road relative to the effective power flow under post-fault equilibrium state; Q is that cut set C is passed through in separation _iinterconnector number;

The transient potential energy obtaining interconnection cut set according to formula (2) is:

$V_{\mathrm{PEtie}}\left(t\right)=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_s}^t[P_k\left(t\right)-P_k^0]\frac{\mathrm{du}}{\mathrm{dt}}\mathrm{dt}---\left(3\right)$

Wherein, V _pEtiet () is the transient potential energy of interconnection cut set, P _kt () to be gained merit time dependent function for branch road, t _sfor fault reaches the moment of post-fault equilibrium point, for branch road phase angle difference is to the derivative of time;

The moment reaching stable equilibrium point due to interconnected network after fault can only get estimated value according to failure condition, and therefore the transient potential energy of interconnection cut set is the Branch Potential Energy sum of transmission cross-section, and formula (3) can be written as:

$V_{\mathrm{PEtie}}\left(t\right)=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_c}^t[P_k\left(t\right)-P_k^0]\frac{\mathrm{du}}{\mathrm{dt}}\mathrm{dt}+V_{\mathrm{PEtie}}\left(t_c\right)---\left(4\right)$

Wherein, t _crepresent the failure removal moment, V _pEtie(t _c) be:

$V_{\mathrm{PEtie}}\left(t_c\right)=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_s}^t[P_k\left(t\right)-P_k^0]\frac{\mathrm{du}}{\mathrm{dt}}\mathrm{dt}---\left(5\right)$

Wherein, V _pEtie(t _c) for kth bar interconnection is from the failure removal moment to the cut set potential energy increment fault stable state.

Interconnection phase angle change rate in described step 2 calculates according to Real-time Collection amount σ (t) of interconnection two ends bus phase angle difference, and its expression formula is:

${\mathrm{\ω}}_{\mathrm{tie}}\left(t\right)=\frac{\mathrm{d\σ}\left(t\right)}{\mathrm{dt}}---\left(6\right)$

Wherein, ω _tiet () is interconnection phase angle change rate, it is as the reference quantity of interconnected network angle stability prognostic criteria.

In described step 3, interconnected network angle stability prognostic criteria can carry out simple computation according to measurement amount and judge in real time.Theoretical foundation is that after impulse fault occurs, interconnected network is filled with a large amount of transient state energy, the total kinetic energy V of interconnected network _kEwith total potential energy V of interconnected network _pEall start to increase, reach maximum to excision fault moment kinetic energy, after this, transient state energy no longer increases, total conservation of energy, and generator energy is converted into the potential energy of network, and kinetic energy reduces gradually, and potential energy continues to increase, and potential energy reaches the extreme value moment, minimum of kinetic energy.Network potential energy reaches the extreme value moment, is embodied in the transient potential energy V of interconnection cut set _pEtiet () reaches the transient potential energy extreme value V of interconnection cut set equally _pEtiemax, according to interconnection phase angle change rate ω _tiet () predicts stability, in the hunting period, the phase difference of voltage rate of change that cut set transient potential energy reaches extreme value moment branch road two ends is zero as interconnected network angle stability prognostic criteria.Interconnected network angle stability prognostic criteria is:

$V_{\mathrm{PEtie}}\left(t\right)=V_{\mathrm{PEtie}\max }\left\{\begin{array}{cc}{\mathrm{\ω}}_{\mathrm{tie}}\left(t\right)=0& \mathrm{St}=1\\ {\mathrm{\ω}}_{\mathrm{tie}}\left(t\right)\≠0& \mathrm{St}=0\end{array}\right.---\left(7\right)$

Wherein, V _pEtiemaxfor the transient potential energy extreme value of interconnection cut set; When St is 1, predicts interconnected network and can keep stable at next pendulum; When St is 0, predicts interconnected network and occur merit angle unstability.

There is merit angle unstability in interconnected network, start the calculating of Transient Stability Control strategy, control object is sending generator;

Calculate failure removal moment interconnected network potential energy, the potential energy of Branch Potential Energy kth interconnected network when time to reach extreme value and failure removal moment interconnected network kinetic energy, specifically have:

$V_2=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_0}^{t_c}\mathrm{\Δ}{P}_{\mathrm{tiek}}\left(t\right){\mathrm{\ω}}_{\mathrm{tiek}}\left(t\right)\mathrm{dt}---\left(8\right)$

$V_3=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_0}^{t_{\mathrm{bk}}}\mathrm{\Δ}{P}_{\mathrm{tiek}}\left(t\right){\mathrm{\ω}}_{\mathrm{tiek}}\left(t\right)\mathrm{dt}---\left(9\right)$

$W_2=\frac{1}{2}{M}_q{\widetilde{\mathrm{\ω}}}_q^2---\left(10\right)$

Wherein, V ₂for failure removal moment interconnected network potential energy, V ₃the potential energy of interconnected network during extreme value is reached, W for Branch Potential Energy kth is secondary ₂for failure removal moment interconnected network kinetic energy.

T ₀for fault moment, t _cfor the failure removal moment, t _bkfor Branch Potential Energy kth time reaches the moment of extreme value, Δ P _tiekt () is the power fluctuation value of kth bar interconnection, ω _tiekt () is kth bar interconnection line phase angle change rate, M _qfor equivalent moment of inertia, for center of inertia angular speed.

In described step 4, if t _bkwhen moment Branch Potential Energy kth time reaches extreme value, the kinetic energy of interconnected network is W ₃, excising unit energy when merit angle unstability appears in interconnected network is Δ W _c;

Have according to law of conservation of energy:

V ₂+W ₂=V ₃+W ₃（11）

Excision generated energy Δ W _cfor:

ΔW _c=W ₃=W ₂+V ₂-V ₃（12）

So the power of excision unit is:

$\mathrm{\Δ}{P}_c=\frac{2\mathrm{\Δ}{W}_C}{T_J}---\left(13\right)$

Wherein, Δ P _cfor excising the power of unit.

Controlling place is the unit nearest apart from shock vibration point electrical distance, needs the potential energy curve of tracking system, judge the stability at next pendulum merit angle of system, prevent the destabilization problems of interconnected network generation plurality of pendulums multigroup after control.If still there is merit angle unstability, need to proceed to control, if stable, then dynamic process terminates.

The present embodiment is described with North China-Central China Power Grid interconnected network simulation example.

Under large load method is put down in Central China in 2011,2200MW is sent in ultra high voltage north, Chongqing of Sichuan power transmission 2440MW, the powered 2800MW in Hunan, short trouble is set at different faults point and impacts (three-phase transient earthing, 0 second fault, 0.1 second failure vanishes), North China-Central China power-angle curve, station, ultra high voltage Nanyang 1000kV busbar voltage curve and ultra high voltage transmission power curve as shown in figs. 2 to 4, can find with sharp mountain impulse fault the most serious.With the stability prediction of North China-Central China Power Grid behind Jiangling and sharp mountain impulse fault and control as example of the present invention, can recover stable by system after proving the accuracy of stability forecast and stability contorting, verify reasonability of the present invention.

The first step: the main contact section of North China-Central China interconnected network is ultra high voltage section, only ultra high voltage transmission line on this cut set, respectively short-circuit impact disturbance is set at Jiangling 500kV bus and sharp mountain 500kV bus, the calculating of cut set potential energy is as formula (5), potential energy is time dependent parameter, and curve respectively as illustrated in Figures 5 and 6.

Second step: after arranging shock vibration respectively, the phase angle change rate of ultra high voltage two ends bus calculates according to formula (6), and result of calculation is respectively as the phase angle change rate in Figure 4 and 5.

3rd step: stability criteria contrasts according to the method for formula (7), be described from Fig. 5 and Fig. 6, in figure, red dotted line is the moment that potential energy reaches extreme value, and in Fig. 5, potential energy reaches extreme value moment phase angle change rate is zero, so system stability after the bus shock vibration of Jiangling, without the need to controlling; Otherwise potential energy reaches the extreme value moment in Fig. 6, although phase angle difference is now little, phase angle change rate is also non-vanishing, so merit angle unstability will occur system after now can predicting sharp mountain bus shock vibration, predicts the outcome consistent with actual emulation result.

4th step: after predicting sharp mountain bus shock vibration, then start the calculating of control strategy.Calculate ultra high voltage interconnection potential energy to reach extreme value moment unnecessary kinetic energy and be about 6000MWs, the inertia time constant T of unit _j=10, need to excise exerting oneself of 1200MW.Therefore after in excision, Pubugou Project power plant 1200MW exerts oneself, System recover is stable, give in Fig. 7 recover stable after ultra high voltage busbar voltage curve.

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, although with reference to above-described embodiment to invention has been detailed description, those of ordinary skill in the field are to be understood that: still can modify to the specific embodiment of the present invention or equivalent replacement, and not departing from any amendment of spirit and scope of the invention or equivalent replacement, it all should be encompassed in the middle of right of the present invention.

Claims (6)

1. the Transient Stability Control method of interconnected network after shock vibration, is characterized in that: said method comprising the steps of:

Step 1: after shock vibration occurs, interconnected network enters transient process, based on transient energy function method, according to the tie-line power transmission gathered in interconnected network and two ends phase angle difference, calculate the transient potential energy of this interconnection cut set, make this interconnection potential energy curve of cyclical fluctuations in time;

Step 2: according to the interconnection two ends bus phase angle difference gathered, calculates interconnection phase angle change rate, makes phase angle change rate curve;

Step 3: judge whether interconnected network occurs merit angle unstability according to interconnected network angle stability prognostic criteria, if so, then start the calculating of Transient Stability Control strategy, control object is sending generator; If not, then show that interconnected network can keep stable at next pendulum;

Step 4: determine the power excising unit according to the calculating of Transient Stability Control strategy, and return step 3 continuation execution, until merit angle unstability does not appear in interconnected network.

2. the Transient Stability Control method of interconnected network after shock vibration according to claim 1, it is characterized in that: in described step 1, transient energy function have employed the structure-preserved topological Liapunov function model of the multimachine system ignoring damping:

$V=V_{\mathrm{KE}}+V_{\mathrm{PE}}=\frac{1}{2}\underset{g=1}{\overset{m}{\mathrm{\Σ}}}{M}_g{\mathrm{\ω}}_g^2+\underset{a=1}{\overset{l}{\mathrm{\Σ}}}{\∫}_{{\mathrm{\σ}}_a^s}^{{\mathrm{\σ}}_a}[P_a\left(u\right)-P_a^s]\mathrm{du}---\left(1\right)$

Wherein, V is the gross energy of interconnected network, V _kEfor the total kinetic energy of interconnected network, V _pEfor total potential energy of interconnected network, m is total number of units of generator, M _git is the moment of inertia of g platform generator; ω _gbe the angular speed of g platform generator, l is the branch road sum of interconnected network, σ _awith be respectively the phase angle difference of a article of branch road and a article of branch road phase angle difference after a failure under poised state; P _a(u) and be respectively the effective power flow of a article of branch road and a article of branch road relative to the effective power flow under post-fault equilibrium state;

If be a unit by each Coherent Generator Group equivalence, then in formula (1), the transient state energy of interconnected network only can consider the transient state energy of interconnection transmission cross-section; If each transmission cross-section is the separation of an interconnected network pass through cut set, if cut set C is passed through in i-th of interconnected network separation _ihave q loop line road, then after fault, the cut set energy of interconnected network is expressed as:

$V_{\mathrm{Cut}}=\frac{1}{2}\frac{M_A{M}_B}{M_A+M_B}{({\widetilde{\mathrm{\ω}}}_A+{\widetilde{\mathrm{\ω}}}_B)}^2+\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{{\mathrm{\σ}}_k^0}^{{\mathrm{\σ}}_k}(P_k\left(u\right)-P_k^0)\mathrm{du}---\left(2\right)$

Wherein, V _cutfor the cut set energy of interconnected network after fault, M _afor the moment of inertia sum of all generators in people having the same aspiration and interest unit A, M _bfor the moment of inertia sum of generators all in people having the same aspiration and interest B of Unit, with be respectively the center of inertia angular speed of people having the same aspiration and interest unit A and people having the same aspiration and interest B of Unit, σ _kwith be respectively the phase angle difference of the kth bar interconnection when the stable equilibrium point of interconnected network after the phase angle difference of kth bar interconnection and fault; P _k(u) and be respectively the effective power flow of kth bar interconnection and kth bar branch road relative to the effective power flow under post-fault equilibrium state; Q is that cut set C is passed through in separation _iinterconnector number;

The transient potential energy obtaining interconnection cut set according to formula (2) is:

$V_{\mathrm{PEtie}}\left(t\right)=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_s}^t[P_k\left(t\right)-P_k^0]\frac{\mathrm{du}}{\mathrm{dt}}\mathrm{dt}---\left(3\right)$

Wherein, V _pEtiet () is the transient potential energy of interconnection cut set, P _kt () to be gained merit time dependent function for branch road, t _sfor fault reaches the moment of post-fault equilibrium point, for branch road phase angle difference is to the derivative of time;

The moment reaching stable equilibrium point due to interconnected network after fault can only get estimated value according to failure condition, and therefore the transient potential energy of interconnection cut set is the Branch Potential Energy sum of transmission cross-section, and formula (3) can be written as:

$V_{\mathrm{PEtie}}\left(t\right)=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_c}^t[P_k\left(t\right)-P_k^0]\frac{\mathrm{du}}{\mathrm{dt}}\mathrm{dt}+V_{\mathrm{PEtie}}\left(t_c\right)---\left(4\right)$

Wherein, t _crepresent the failure removal moment, V _pEtie(t _c) be:

$V_{\mathrm{PEtie}}\left(t_c\right)=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_s}^{t_c}[P_k\left(t\right)-P_k^0]\frac{\mathrm{du}}{\mathrm{dt}}\mathrm{dt}---\left(5\right)$

Wherein, V _pEtie(t _c) for kth bar interconnection is from the failure removal moment to the cut set potential energy increment fault stable state.

3. the Transient Stability Control method of interconnected network after shock vibration according to claim 1, it is characterized in that: the interconnection phase angle change rate in described step 2 calculates according to Real-time Collection amount σ (t) of interconnection two ends bus phase angle difference, and its expression formula is:

${\mathrm{\ω}}_{\mathrm{tie}}\left(t\right)=\frac{\mathrm{d\σ}\left(t\right)}{\mathrm{dt}}---\left(6\right)$

Wherein, ω _tiet () is interconnection phase angle change rate, it is as the reference quantity of interconnected network angle stability prognostic criteria.

4. the Transient Stability Control method of interconnected network after shock vibration according to claim 1, is characterized in that: the interconnected network angle stability prognostic criteria in described step 3 is:

$V_{\mathrm{PEtie}}\left(t\right)=V_{\mathrm{Petie}\max }\left\{\begin{array}{cc}{\mathrm{\ω}}_{\mathrm{tie}}\left(t\right)=0& \mathrm{St}=1\\ {\mathrm{\ω}}_{\mathrm{tie}}\left(t\right)\≠0& \mathrm{St}=0\end{array}\right.---\left(7\right)$

Wherein, V _pEtiemaxfor the transient potential energy extreme value of interconnection cut set; ω _tiet () is interconnection phase angle change rate; When St is 1, predicts interconnected network and can keep stable at next pendulum; When St is 0, predicts interconnected network and occur merit angle unstability.

5. the Transient Stability Control method of interconnected network after shock vibration according to claim 4, is characterized in that: merit angle unstability appears in interconnected network, and start the calculating of Transient Stability Control strategy, control object is sending generator;

Calculate failure removal moment interconnected network potential energy, the potential energy of Branch Potential Energy kth interconnected network when time to reach extreme value and failure removal moment interconnected network kinetic energy, specifically have:

$V_2=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_0}^{t_c}\mathrm{\Δ}{P}_{\mathrm{tiek}}\left(t\right){\mathrm{\ω}}_{\mathrm{tiek}}\left(t\right)\mathrm{dt}---\left(8\right)$

$V_3=\underset{k=1}{\overset{q}{\mathrm{\Σ}}}{\∫}_{t_0}^{t_{\mathrm{bk}}}\mathrm{\Δ}{P}_{\mathrm{tiek}}\left(t\right){\mathrm{\ω}}_{\mathrm{tiek}}\left(t\right)\mathrm{dt}---\left(9\right)$

$W_2=\frac{1}{2}{M}_q{\widetilde{\mathrm{\ω}}}_q^2---\left(10\right)$

Wherein, V ₂for failure removal moment interconnected network potential energy, V ₃the potential energy of interconnected network during extreme value is reached, W for Branch Potential Energy kth is secondary ₂for failure removal moment interconnected network kinetic energy; t ₀for fault moment, t _cfor the failure removal moment, t _bkfor Branch Potential Energy kth time reaches the moment of extreme value, Δ P _tiekt () is the power fluctuation value of kth bar interconnection, ω _tiekt () is kth bar interconnection phase angle change rate, M _qfor equivalent moment of inertia, for center of inertia angular speed.

6. the Transient Stability Control method of interconnected network after shock vibration according to claim 5, is characterized in that: in described step 4, if t _bkwhen moment Branch Potential Energy kth time reaches extreme value, the kinetic energy of interconnected network is W ₃, excising unit energy when merit angle unstability appears in interconnected network is Δ W _c;

Have according to law of conservation of energy:

V ₂+W ₂＝V ₃+W ₃(11)

Excision generated energy Δ W _cfor:

ΔW _c＝W ₃＝W ₂+V ₂-V ₃(12)

So the power of excision unit is:

${\mathrm{\ΔP}}_c=\frac{2\mathrm{\Δ}{W}_c}{T_J}---\left(13\right)$

Wherein, Δ P _cfor excising the power of unit.