CN105610161B - Dynamic impedance based stability characteristic estimation method of power system - Google Patents

Abstract

The invention discloses a dynamic impedance based stability characteristic estimation method of a power system. The method comprises the following steps of 1, acquiring connection characteristic of a target network; 2, setting a disturbance mode, and figuring a dynamic equivalence impedance matrix of each moment according to a power flow equation; 3, obtaining dynamic characteristics of a source-network-charge node of the power system according to the dynamic equivalence impedance matrix; and 4, calculating a self-stabilization factor and a stabilization factor of the node according to different source-network-charge dynamic electric characteristics for analyzing the characteristic between the node and the whole network. By the method, the influence characteristic among nodes during the dynamic process can be quantitatively analyzed, and finally, the dynamic characteristic between each node and the whole network is obtained.

Description

A kind of power system stability method of evaluating characteristic based on motional impedance

Technical field

The present invention relates to a kind of power system stability method of evaluating characteristic based on motional impedance.

Background technology

With the fast development of global economy, the scale of electric power networks is also increasing, especially new technology and equipment Constantly application is so that the characteristic between electrical network each several part becomes increasingly complex.The safe and stable operation of electric power networks increasingly relation To national economy and national security.With the continuous expansion of electrical network scale, the dynamic characteristic of electrical network increasingly embodies complexity Nonlinear characteristic, traditional modeling method has been increasingly difficult to calculate the coupling correlation degree between each node. In conventional system call is run, staff often can only pass through the dynamic characteristic of micro-judgment electric power networks, for each Dynamic characteristic between part and its effect played are unable to quantitative analysis, and the whole world all there occurs a lot of things of having a power failure on a large scale in recent years Therefore, and the origin cause of formation for accident and the clear and definite conclusion of the mechanism of transmission all neither ones up to now, by analyzing the dynamic of network The size that influences each other between characteristic and each several part, can deeper into the characteristic understanding electrical network itself.

It is known that in network analysis technique, analyzing often from the angle of network structure for a complex network The index such as degree, such as degree, Jie, these indexs be have ignored network parameter, are not exclusively consistent with electric power networks.Substantial amounts of research shows, In electric power networks, usually there are some nodes to be easier to affect whole network, or have some nodes to be easier by other node institutes Impact, so be targetedly analyzed to whole power system dynamic step response on the basis of needing to consider further that electric parameter.

In conventional network characteristic research, network parameter is often thought that it is static parameter, branch parameters (R, L, C it is) then embodying of element characteristic, further illustrate the relation between source-net-lotus, and from the beginning of before 20 years, just constantly Have the analysis equivalent to power system of document utilization Dai Weinan (Thevenin's) equivalence method；But work as branch parameters (R, L, C) When relevant with electricity, the parameter after equivalence is exactly nonlinear parameter, and interrelationship is also non-linear relation, such net Network is exactly nonlinear network, so for the analysis of source-net-lotus characteristic in power system, needing to consider dynamic branch parameters shadow Ring.

Existing application of net, in Power System Analysis, is also all mainly to analyze one from static angular to have electrically In the network structure of parameter characteristic, the contact that intercouples between each several part is strong and weak, and thinks the mutual shadow between two nodes Sound is identical, but this and actual not in full conformity with power system, the voltage that both there are part of nodes in practical power systems holds It is vulnerable to the impact of other node Injection Currents change, but the node voltage to other nodes for the change of this node Injection Current Impact is less；The voltage that again there is part of nodes is not easy to be affected by the change of other node Injection Currents, but this node note The change entering electric current but has the situation of considerable influence to the node voltage of other nodes, and that is, the degree that influences each other between region is big Little not consistent.It is thus desirable to providing a kind of power system stability method of evaluating characteristic, effectively can analyze from dynamic angle This node impacts size to other nodes, and other nodes impact size to this node.

The dynamic analysing method commonly used at present has little interference analytic approach, time-domain-simulation method and dynamic power flow method etc..Closely several Year also constantly there is new dynamic analysing method to propose, such as set up multiobjective Dynamic Optimization model, calculating dynamic power flow is it is considered to network Structure entropy etc., but mainly it is both for a certain carrying out practically condition so that result has certain limitation it is impossible to measure completely Change the dynamic electrical characteristic between each region and its significance level therefore exigence provides a kind of energy real-time quantization tracking dynamic The appraisal procedure of power system stability characteristic during state.

Content of the invention

Technical problem solved by the invention is, for application of net in the actual deficiency of power system, there is provided A kind of power system stability method of evaluating characteristic based on motional impedance, can analyze in real time source in network-each node of net-lotus it Between dynamic electrical characteristic.

The present invention provide technical scheme be：

A kind of power system stability method of evaluating characteristic based on motional impedance, comprises the following steps：

Step 1：In whole power system, obtain the current power network connection characteristic needing to analyze the moment, power network Network connection performance includes network topology structure and the network topology parameters of power system；

Step 2：Setting perturbation scheme, selects arbitrary real number parameter λ that can reflect system running state, and follows the tracks of disturbance The change of λ afterwards；As long as λ real variable, and operation of power networks state can be reflected it is possible to be suitable for follow-up formula to carry out power system Stability characteristic (quality) appraisal procedure；

Ask for the dynamic equivalent impedance matrix Z in each moment by Load flow calculation_dyn/λ；

In this matrix, the element of the i-th row jth row is：

For the node voltage of i node,For the Injection Current of j node, 1≤i, j≤m+ s+n；M is generator node number, and n is load bus number, and s is connecting node number；

Step 3：According to the dynamic equivalent impedance matrix of step 2 gained, dynamically electric between the source of asking for-net-lotus node Characteristic；Specific as follows：

Wherein：

Subscript G, T and L represent generator node, connecting node and load bus respectively；Table respectively Show the node voltage variable quantity column vector of engine nodal, connecting node and load bus；Represent respectively and send out The Injection Current variable quantity column vector of motivation node, connecting node and load bus；Z_GLRepresent generator node to load bus Dynamic mutual impedance；

Taking the characteristic between load bus and other nodes as a example, the node voltage variable quantity column vector calculation of load bus Formula is as follows：

Wherein have：

E is unit matrix, and N is the system equivalent impedance matrix towards load, and M is load bus voltage and generator node Voltage relationship matrix；

Specific to load bus i, 1≤i≤n, have：

Wherein M_ikIt is matrix M the i-th row k column element, N_iiIt is the element of matrix N the i-th row i row, N_ijIt is matrix N the i-th row j row Element；Order

Then have：

Wherein,Represent the voltage variety of load bus i；△U_GikThe voltage change representing generator node k is to negative The impact of lotus node i voltage；△U_LiiRepresent that the Injection Current of load bus i changes the impact to its voltage；△U_LijRepresent The impact to load bus i voltage for the Injection Current change of load bus j；

For simplifying the analysis it is considered to generator reactive power is not out-of-limit, the power of generator node and section in theoretical research Point voltage is constant, and now the voltage of generator node is constant, so Section 1 is 0, can ignore, then have

Have ignored Section 1 in subsequent calculations from the steady factor with when causing the steady factor, if not ignoring, calculating side Method is also consistent it is only necessary to consider the node voltage of PV node situation when changing in the current situation.

It can be seen that the voltage of load bus i is subject to three below some effects：

1) impact of generator node voltage change.

2) impact of i load current voltage drop change on self-impedance.

3) impact of the voltage drop change in corresponding mutual impedance of other load currents in addition to i.

This three's collective effect makes this node voltage fluctuate it can be seen that the node voltage of load bus i is when current Carve easily affected degree, by further three different piece proportions of comparative analysis, can also obtain affecting load Leading factor in the voltage of node i.Can be derived from the voltage-current relationship formula of generator side in the same manner, by decomposing different impacts Factor, can analyse in depth source-net-lotus mutual dynamic characteristic variation tendency and its leading factor.

When for electric power system source-net-lotus dynamically electrically specificity analysis, according to actual needs, each node can be compared There is characteristic during identical Injection Current variable quantity.By above-mentioned analysis, that is, quantify to have decoupled between load bus and other nodes Dynamic characteristic, dynamic characteristic between other types node can also be pushed away to obtain in the same manner.

Further, the above-mentioned power system stability method of evaluating characteristic based on motional impedance, further comprising the steps of：

Step 4：By dynamic equivalent impedance matrix, analyze the dynamic electrical characteristic of each node further, be mainly reflected in Self-stability and cause stability, respectively with from the steady factor and the steady factor representation of cause；

(3) i-node from the steady factor：

From steady factor ZU_iRepresent, illustrate the self-stability of i-node, embody every other node and shadow is caused to i-node Ring the mean value of size, the dynamic electrical characteristic that is, i-node is affected by whole network；Computing formula is as follows：

Wherein, n represents the number of load bus；

(4) the steady factor of the cause of j node：

Cause steady factor ZI_jRepresent, illustrate the cause stability of j node, embody j node and other nodes are impacted greatly Little mean value, the dynamic electrical characteristic that is, j node affects on whole network；Computing formula is as follows：

Wherein, n represents the number of load bus.

Above-mentioned real number parameter λ is Injection Current real part or the injected system changed power factor of node.

The power system stability method of evaluating characteristic based on motional impedance of the present invention, can be suitably used for all of disturbance side Formula, real variable can select arbitrary real number parameter that can reflect system running state, such as the Injection Current real part of node or note Enter system power changed factor.Except the disturbance moment of large disturbances, because voltage is undergone mutation, node is from steady/steady factor meeting of cause There is Spline smoothing, so inapplicable this method at that moment, do not consider mutation at that moment, the subsequent dynamic of large disturbances is steady Determine characteristic evaluation and can be suitable for this method；If not large disturbances, there is no situation about being mutated, be then suitable for this method.

This method power supply and load injection work(on the basis of conventional linear electric network analysis it is contemplated that in power system Rate, neither voltage source, is not current source, exists compared with the basis of strong nonlinearity characteristic, calculates dynamic equivalent impedance matrix, moves State impedance matrix has clear and definite physical significance, and matrix element can embody the relation that intercouples between any two node, And quantify to follow the tracks of its variation tendency, deeply understand the complicated electrical link between electrical network each several part, decoupling under different service conditions Coupled characteristic between source-net-lotus simultaneously analyzes its leading factor, by passing judgment on the electric stability characteristic (quality) of source-net-lotus node, point Do not analyze its self-stability and cause stability, can be with the stability characteristic (quality) of the whole power system of grasp macroscopical.

The method energy correct amount dissolves the dynamic characteristic in steady-state process or even transient state, can fast and accurately judge source- Net-lotus node is easily by other node effect sizes with easily to other nodes generation effect size, permissible The understanding to the peculiar electric dynamic characteristics of power system for the in-depth, illustrates the validity of the method by time-domain-simulation.

Beneficial effect：

Using this method, creative is incorporated among Electrical Power System Dynamic analysis, by electricity by network analysis technique The assessment of Force system stability characteristic (quality), understanding electric power networks characteristic that can be more deep, for scheduling planning and power grid construction There is directive significance.

1st, intuitively quantitative analysis dynamic characteristic between source-net-lotus node can be gone out using this method, can be from macroscopically Hold the exclusive electrical characteristic of each node in whole network, theoretically illustrate the origin cause of formation of different node electrical characteristics.

2nd, use the method for the present invention, follow the tracks of to source-each node dynamics of net-lotus change, can analyze further Its main affecting parameters and main influence area, and targetedly revise the electricity of source-net-lotus node during management and running Gas characteristic

3rd, in system call running, fast and accurately determine the electrical characteristic that has of source-net-lotus node and divide Analyse its leading factor and there is good realistic meaning, theory support can be provided for the operation of next step.Each source-net-lotus node Electrical characteristic determine simple to operate, calculate quick, solve under current bulk power grid interconnection reality, the electricity that power system is embodied The difficult problem that gas characteristic becomes increasingly complex.

Brief description

Fig. 1 is the inventive method flow chart；

Fig. 2 is the network connection figure of 3 node chained form systems

Fig. 3 is the node of 3 node chained form systems from the steady factor

Fig. 4 is that the node of 3 node chained form systems causes the steady factor

Fig. 5 is IEEE39 node system network connection figure

Fig. 6 be IEEE39 node system not node in the same time from the steady factor

Fig. 7 is that IEEE39 node system node not in the same time causes the steady factor

Fig. 8 wants grid structure schematic diagram for Central China power saving host

Fig. 9 is the node of part of nodes during Central China province electrical network difference moment from the steady factor

Figure 10 is that the node of part of nodes during Central China province electrical network difference moment causes the steady factor

Specific embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in more detail.

Fig. 1 is the inventive method flow chart.

Embodiment 1：

By to the simple chain type system emulation of 3 nodes, illustrating a kind of to comment based on the power system stability characteristic of motional impedance Estimate method, comprise the following steps：

Step 1：In 3 node systems, obtain analyzing the network connection characteristic in moment.Concrete data as shown in Figure 2, is disturbed Flowing mode adopts synchronizing power to increase disturbance.

Step 2：Setting the whole network synchronizing power increases disturbance, and based on PSASP, whole power system is calculated, and obtains The flow data in part moment is as follows：

It is calculated the dynamic equivalent impedance matrix of etching system during part：

During t=1：

During t=1.1：

During t=1.2：

Step 3：Can be seen that in source-net-lotus characteristic now after taking absolute value, with the increase of load level, different Contact characteristic between node is strengthened, and the impact to No. 3 nodes of No. 2 nodes will be weaker than the impact to No. 2 nodes for No. 3 nodes, Here it is the source of power system-dynamic electrical characteristic of net-lotus.

Step 4：Calculate i-node from steady factor Z U_iSteady factor Z I with the cause of j node_jAs shown in Figure 3 and Figure 4.Can see Go out, in single-ended power chain type simple network, index ZU_iAnd ZI_jAll that No. 3 nodes are larger, this show the node of No. 3 nodes from steady/ Cause the steady factor will be more than No. 2 nodes that is to say, that not only No. 2 nodes of voltage ratio of No. 3 nodes will be more susceptible to affect, and And the identical Injection Current change of No. 3 nodes is bigger on whole system impact.From physical significance, above-mentioned phenomenon this be by It is in system end in No. 3 nodes, farther out and whole network is single-ended power chain network from the power supply strong point, meet end electricity The relatively low operating experience of pressure maintenance level.

Dynamic equivalent impedance matrix mainly reflects the dynamic characteristic between different nodes, in actual motion system, by Constantly it is in it is only necessary to the node for emphasis detection is analyzed among change in whole network, so operand is less, by Larger in matrix, so not providing specific dynamic equivalent impedance matrix in follow-up example, mainly for node and whole net Contact characteristic between network has been made to analyze.

Embodiment 2：

By to IEEE39 system emulation, a kind of power system stability method of evaluating characteristic based on motional impedance being described, Comprise the following steps：

Step 1：In IEEE39 node system, obtain analyzing the network connection characteristic in moment.Network connection such as Fig. 5 institute Show, network parameter such as following table, perturbation scheme adopts synchronizing power to increase disturbance.

Step 2：Setting the whole network synchronizing power increases disturbance, based on PSASP, whole system is calculated, and obtains part moment tide Flow data () as follows taking load bus as a example：

During t=0.79

During t=0.8

During t=0.89

During t=0.9

During t=0.99

During t=1

By Load flow calculation, the dynamic equivalent impedance matrix of IEEE39 node system can be calculated in the same manner.

Step 3：Can be seen that in source-net-lotus characteristic now after taking absolute value, with the increase of load level, different Contact characteristic between node first weakens to be strengthened again, illustrates that a certain degree of load growth can be so that under some methods of operation be Contact characteristic between system weakens.

Step 4：Calculate node causes the steady factor as shown in Figure 6 and Figure 7 from the steady factor and node.

As seen from Figure 6, the node of all nodes increases first slow reduction from the steady factor with load, then gradually increases Plus.Illustrate that a certain degree of load growth reduces the electrical couplings characteristic between node and network on the contrary, that is, node is subject to network Effect reduces, but after load growth is more, node is affected be more susceptible to other nodes, this and single-ended power chain Formula network analysis is consistent.

With the growth of load level, exist so that node is interval from the less optimum load of the steady factor, this load setting The each part of interior power system influences each other less, can weaken the propagation of fault.

Again it can be seen that IEEE39 system is under the current method of operation, the node of the larger node of nargin is from the steady factor relatively Little, the voltage of this node is not readily susceptible to affect all the better, and the node close to transmission power limit, such as node 20, its voltage It is easier big ups and downs.

Fig. 7 interior joint causes steady factor variations less, and this increases to electrical network coupling mainly due to the whole network synchronous payloads Characteristic impact is less.During 0.8 to 0.9, node fluctuation has reduced load power parameter λ, and λ is from 0.9 to 1 process In, node fluctuation is increased slightly.Illustrate that a certain degree of load growth reduces the influence degree to other nodes for this node, but After load growth is more, can make this node that other node influence degrees are aggravated, exist so that node causes the steady factor less Optimum load is interval, consistent from steady factorial analysis conclusion with node.It can be seen that although the stability margin of node 13 is larger, Because its node causes the steady factor also larger, so the fault around node 13 is more serious to the impact of whole network, need Pay close attention to.

Comprehensive above analysis understands：

1) in single system, there is the node of small voltage stability margin, typically have larger node from the steady factor, closer to The node of voltage stability limit, voltage is easier fluctuation on the contrary it is easy to be affected by other nodes.

2), in single system, load level and node are in negative correlation from the steady factor all and voltage stability margin between.But Node cause the relation of the steady factor and voltage stability margin then more complicated property for same node, node when load is heavier Voltage stability margin is less, and node is bigger from the steady factor, is more easily affected by other nodes；But node causes the steady factor and electricity It is not simple monotonic relationshi between pressure stability margin.

3) under certain method of operation, there is an optimum load interval, the node of electrical network each several part in here interval All less from the steady factor and the steady factor of node cause, coupled relation is not tight, influences each other weak.

In order to illustrate that node, from the steady factor of the steady factor/cause, has for than more typical example：No. 20 nodes and No. 13 nodes. No. 20 nodes have larger node and cause the steady factor from the steady factor and less node, illustrate that the voltage of this node is easily subject to other The impact in region, but the change of the Injection Current of this node is not easy to affect other nodes, notices that stablizing of this node is abundant simultaneously Degree is also less, so the voltage levvl for this node needs emphasis to monitor.Node 13 has less node from the steady factor, voltage Be not readily susceptible to the impact in other regions, when breaking down when other regions, the fluctuation of node 13 is less, and this node stablize abundant Degree is larger.Although this node distance limits operating point itself is farther out, because node 13 has larger node to cause the steady factor, should When near nodal breaks down, the impact changing to whole network of Injection Current is larger, once fault occurred in this node week When enclosing, and making the Injection Current generation large change of node 13, larger power network fluctuation can be caused and lead to power flow transfer, institute To need emphasis to monitor the fault around node 13.

Electrical couplings relation between each part of electrical network is at every moment changing, and each node is in different fortune Row moment, the different methods of operation, suffer from different electrical couplings characteristic under different service conditions, by observing source The dynamic characteristic of net lotus and its change, can be better understood from the coupling contact between each region of complex electric network, be management and running Instruction is provided.

Embodiment 3：

By to the actual motion system emulation of Central China province, a kind of power system stability characteristic based on motional impedance being described Appraisal procedure, comprises the following steps：

Step 1：Within the system, obtain analyzing the network connection characteristic in moment.Main grid structure as shown in Figure 8, Part major parameter such as following table, perturbation scheme adopts synchronizing power to increase disturbance.

Step 2：Setting the whole network synchronizing power increases disturbance, based on PSASP, whole power system is calculated, obtains portion The flow data in each moment of partial node is as follows：

During t=0.99

During t=1

During t=1.09

During t=1.1

During t=1.19

During t=1.2

By the variable quantity of node voltage and Injection Current, the dynamic equivalent impedance matrix of system can be calculated：

Step 3：Can be seen that in source-net-lotus characteristic now after taking absolute value, with the increase of load level, different Contact characteristic between node is strengthened.

Step 4：Calculate node is from steady factor Z U_iCause steady factor Z I with node_jAs shown in Figure 9 and Figure 10.

Can be seen that node from Fig. 9 and Figure 10 to be proportionate with load level from the steady factor of the steady factor/cause, transport current Increase load level under line mode, the electrical link between source-net-lotus can be made even closer.

Simulation result is analyzed, the coupled characteristic of this province net presents following features：

1) contrast IEEE39 node system understands, the variation tendency of voltage stability margin is basically identical, but node is from surely All downward trend as in IEEE39 node system in the steady factor of the factor/cause, and the uniform increasing with load is described Long, the source-net between each region of electrical network-charged gas coupled characteristic is gradually strengthened, and the degree of influencing each other between zones of different adds Play, under same fault, the impact suffered by the whole network is bigger, is unfavorable for that maintenance voltage is stable.This province's net is in the current method of operation Lower increase load level, can make voltage be more susceptible to affect, fault is easier to propagate.

2) it is directed to typical transformer station LDH and JT analysis.The node of LDH transformer station is maximum from the steady factor, and current operation is described Under the conditions of this transformer station voltage be easiest to fluctuate, easily by other regional effects, load growth simultaneously can make this transformer station Node increases suddenly from the steady factor, and its voltage is easier to fluctuate, and in the transformer station of all supervision, LDH voltage is by being affected Maximum, should monitor the voltage of this transformer station by emphasis during traffic control.And the maximum power transformation of the steady factor is caused for node Stand JT, needs emphasis to monitor the fault in region about.

3) for complication system, under conditions of network structure determines, single margin index can only investigate current operation " distance " between point and utmost operational points, is not enough to accurately comprehensively reflecting voltage stability only by this index.Nargin The big node of index is likely to be of larger node and causes the steady factor/from the steady factor, thus may refer to than nargin under certain condition Mark little node to be easier Voltage Instability to occur it is also possible to the impact to whole network voltage levvl is bigger.

Claims (4)

1. a kind of power system stability method of evaluating characteristic based on motional impedance is it is characterised in that comprise the following steps：

Step 1：In whole power system, obtain the current power network connection characteristic needing to analyze the moment, electric power networks are even Connect network topology structure and the network topology parameters that characteristic includes power system；

Step 2：Setting perturbation scheme, selects arbitrary real number parameter λ that can reflect system running state, and follows the tracks of λ after disturbance Change；

Ask for the dynamic equivalent impedance matrix Z in each moment by Load flow calculation_dyn/λ；

In this matrix, the element of the i-th row jth row is：

For the node voltage of i node,For the Injection Current of j node, 1≤i, j≤m+s+n；m It is generator node number, n is load bus number, s is connecting node number；

Step 3：According to the dynamic equivalent impedance matrix of step 2 gained, the dynamic electrical characteristic between the source of asking for-net-lotus node, Characterized by the node voltage variable quantity of each node；Specific as follows：

$\left[\begin{array}{c}A{\stackrel{\·}{U}}_G\\ A{\stackrel{\·}{U}}_T\\ A{\stackrel{\·}{U}}_L\end{array}\right]=\left[\begin{array}{ccc}{Z}_{GG}& Z_{GT}& Z_{GL}\\ Z_{TG}& Z_{TT}& Z_{TL}\\ Z_{LG}& Z_{LT}& Z_{LL}\end{array}\right]\left[\begin{array}{c}\mathrm{\Δ}{\stackrel{\·}{I}}_G\\ \mathrm{\Δ}{\stackrel{\·}{I}}_T\\ \mathrm{\Δ}{\stackrel{\·}{I}}_L\end{array}\right]$

Wherein：

$\mathrm{\Δ}{\stackrel{\·}{U}}_G=\left[\begin{array}{c}\mathrm{\Δ}{\stackrel{\·}{U}}_{G1}\\ \mathrm{\Δ}{\stackrel{\·}{U}}_{G2}\\ .\\ .\\ .\\ \mathrm{\Δ}{\stackrel{\·}{U}}_{Gm}\end{array}\right],\mathrm{\Δ}{\stackrel{\·}{U}}_T=\left[\begin{array}{c}\mathrm{\Δ}{\stackrel{\·}{U}}_{T1}\\ \mathrm{\Δ}{\stackrel{\·}{U}}_{T2}\\ .\\ .\\ .\\ \mathrm{\Δ}{\stackrel{\·}{U}}_{Ts}\end{array}\right],\mathrm{\Δ}{\stackrel{\·}{U}}_L=\left[\begin{array}{c}\mathrm{\Δ}{\stackrel{\·}{U}}_{L1}\\ \mathrm{\Δ}{\stackrel{\·}{U}}_{L2}\\ .\\ .\\ .\\ \mathrm{\Δ}{\stackrel{\·}{U}}_{Ln}\end{array}\right],$

$\mathrm{\Δ}{\stackrel{\·}{I}}_G=\left[\begin{array}{c}\mathrm{\Δ}{\stackrel{\·}{I}}_{G1}\\ \mathrm{\Δ}{\stackrel{\·}{I}}_{G2}\\ .\\ .\\ .\\ \mathrm{\Δ}{\stackrel{\·}{I}}_{Gm}\end{array}\right],\mathrm{\Δ}{\stackrel{\·}{I}}_T=\left[\begin{array}{c}\mathrm{\Δ}{\stackrel{\·}{I}}_{T1}\\ \mathrm{\Δ}{\stackrel{\·}{I}}_{T2}\\ .\\ .\\ .\\ \mathrm{\Δ}{\stackrel{\·}{I}}_{Ts}\end{array}\right],\mathrm{\Δ}{\stackrel{\·}{I}}_L=\left[\begin{array}{c}\mathrm{\Δ}{\stackrel{\·}{I}}_{L1}\\ \mathrm{\Δ}{\stackrel{\·}{I}}_{L2}\\ .\\ .\\ .\\ \mathrm{\Δ}{\stackrel{\·}{I}}_{Ln}\end{array}\right];$

Subscript G, T and L represent generator node, connecting node and load bus respectively；Represent respectively and send out The node voltage variable quantity column vector of motivation node, connecting node and load bus, the node voltage in order to characterize each node exists Current time easily affected degree；Represent engine nodal, connecting node and load bus respectively Injection Current variable quantity column vector；

The node voltage variable quantity column vector calculation formula of load bus is as follows：

$A{\stackrel{\·}{U}}_L=M\mathrm{\Δ}{\stackrel{\·}{U}}_G+N\mathrm{\Δ}{\stackrel{\·}{I}}_L$

Wherein have：

$\left\{\begin{array}{c}M={(E+{\mathrm{TZ}}_{LL}^{-1})}^{-1}{\mathrm{TZ}}_{GL}^{-1}\\ N={(E+{\mathrm{TZ}}_{LL}^{-1})}^{-1}{Z}_{LL}\\ T=Z_{LG}{(Z_{GL}^{-1}{Z}_{GG}-Z_{LL}^{-1}{Z}_{LG})}^{-1}\end{array}\right.$

E is unit matrix, and N is the system equivalent impedance matrix towards load, and M is load bus voltage and generator node voltage Correlation matrix；

Specific to load bus i, 1≤i≤n, have：

$\mathrm{\Δ}{\stackrel{\·}{U}}_{Li}=\underset{k=1}{\overset{m}{\Σ}}{M}_{ik}\mathrm{\Δ}{\stackrel{\·}{U}}_{Gk}+N_{ii}\mathrm{\Δ}{\stackrel{\·}{I}}_{Li}+\underset{j=1,j\≠i}{\overset{n}{\Σ}}{N}_{ij}\mathrm{\Δ}{\stackrel{\·}{I}}_{Lj}$

Wherein M_ikIt is matrix M the i-th row k column element, N_iiIt is the element of matrix N the i-th row i row, N_ijIt is the unit of matrix N the i-th row j row Element；Order

Then have：

$\mathrm{\Δ}{\stackrel{\·}{U}}_{Li}=\underset{k=1}{\overset{m}{\mathrm{\Δ}}}{\mathrm{\ΔU}}_{Gik}+{\mathrm{\ΔU}}_{Lii}+\underset{j=1,j\≠i}{\overset{n}{\Σ}}{\mathrm{\ΔU}}_{Lij}$

Wherein,Represent the voltage variety of load bus i；ΔU_GikThe voltage change representing generator node k is to load section The impact of point i voltage；ΔU_LiiRepresent that the Injection Current of load bus i changes the impact to its voltage；ΔU_LijRepresent load The impact to load bus i voltage for the Injection Current change of node j；

OrderObtain

2. the power system stability method of evaluating characteristic based on motional impedance according to claim 1 is it is characterised in that divide Do not calculateWithRatio, obtain affect load bus i voltage leading factor.

3. the power system stability method of evaluating characteristic based on motional impedance according to claim 1 is it is characterised in that go back Comprise the following steps：

Step 4：By dynamic equivalent impedance matrix, analyze each node from the steady factor and cause steady factor representation；

(1) i-node from the steady factor：

From steady factor ZU_iRepresent, illustrate the self-stability of i-node, embody every other node and i-node is impacted greatly Little mean value, the dynamic electrical characteristic that is, i-node is affected by whole network；Computing formula is as follows：

${\mathrm{ZU}}_i=\frac{1}{n}|{\mathrm{\ΔU}}_{Lii}+\underset{j=1,j\≠i}{\overset{n}{\Σ}}{\mathrm{\ΔU}}_{Lij}|$

Wherein, n represents the number of load bus；

(2) the steady factor of the cause of j node：

Cause steady factor ZI_jRepresent, illustrate the cause stability of j node, embody j node and size is impacted to other nodes Mean value, the dynamic electrical characteristic that is, j node affects on whole network；Computing formula is as follows：

${\mathrm{ZI}}_j=\frac{1}{n}|{\mathrm{\ΔU}}_{Lii}+\underset{i=1,j\≠i}{\overset{n}{\Σ}}{\mathrm{\ΔU}}_{Lij}|$

Wherein, n represents the number of load bus.

4. the power system stability method of evaluating characteristic based on motional impedance according to any one of claims 1 to 3, its It is characterised by, described real number parameter λ is Injection Current real part or the injected system changed power factor of node.