CN101895116B - Online available transmission capacity computing method based on distribution factor - Google Patents

Abstract

The invention discloses an online available transmission capacity computing method based on distribution factor, including the following steps: (1) a basic section is acquired and generated; (2) load flow calculation on the basic section is carried out; (3) sensitivity of branch active power to node active power injection is calculated; (4) a breaking line fault set is formed; (5) sensitivity of branch active power to engine active power is calculated, when engine of a computer is under ATC condition of N-1 breaking, sensitivity of branch active power to engine active power is calculated, and correction is carried out on the sensitivity of branch active power to engine active power calculated in the step (3); (6) point-to-point available transmission capacity is calculated; (7) available transmission capacity of important section is calculated. The method of the invention has small calculated amount and improves calculating speed.

Description

Online Calculation of Available Transfer Capability method based on distribution factor

Technical field

The invention belongs to technical field of power systems, the present invention relates to a kind of Calculation of Available Transfer Capability method that is applied in the online network analysis based on distribution factor more precisely.

Background technology

Power market reform has also proposed stern challenge to the fail safe and the stability of electric power system when bringing great economic benefit and social benefit.U.S.A adds to have a power failure on a large scale makes increasing people recognize, must satisfy the economy that improves electrical network under the stable prerequisite of safe operation of electric network.Electric power system available transmission capacity (ATC) is the rich ability to transmit electricity that on existing transmission of electricity agreement basis, can be used for further business activity.ATC has very big influence in line computation for the security reliability of whole electric power system; Its interregional ability to transmit electricity that calculates is the important references information of system call person when dispatching; It can make the dispatcher understand the distance of the various constraints of system current operating state distance, prevents the generation of situation such as branch road overload, section transient stability be out-of-limit.

The calculating of ATC comprises two big class methods: randomness method for solving and certainty method for solving.So-called randomness method for solving is also claimed the computational methods based on probabilistic model, promptly utilizes the relevant knowledge analysis of probability theory and mathematical statistics and finds the solution the interregional available transmission capacity of electric power system.Concrete computational process is divided into following three steps: random fault and the Load distribution of 1, sending out transmission facility through the probabilistic method simulation; 2, utilize optimized Algorithm to find the solution the ATC under each running status respectively; 3, utilize statistical analysis technique to calculate desired value and the probability distribution thereof of ATC under each running status, and confirm to consider the optimum ATC value of economic benefit maximum thus.Probabilistic model can be taken into account the influence of various uncertain factors to ATC rationally, effectively, but computational process is complicated, computational speed is slow, is not suitable for online application.The certainty method for solving is also claimed the ATC computational methods based on deterministic models, promptly is the basis with known system mode, through the fault screening, uses appropriate method calculating then and satisfies the ATC under the various malfunction constraintss.Deterministic models are easy to realize, computational speed is very fast, be fit to ATC in line computation.The certainty method for solving generally is divided into: distribution factor method, continuous tide method, optimal load flow method, sensitivity method etc.

The linear distribution factorization method of in the document one " calculating the method commentary of available transfer capacity of transmission network " (relay was rolled up 45 pages of the 10th phases in 2003 the 31st) ATC being calculated has been carried out simple argumentation; Consider that the processing method of frequency modulation characteristic fully studies when the modification method of line sensitivity, the screening technique that cut-offs the fault collection, the generator outage but concrete computational methods, the equipment of distribution factor is not cut-off the back, seem too rough.

Document two " research of transmission system available transmission capacity " (Power System and its Automation journal 2005 the 17th volume the 5th phase 42 pages) is from the model of practicability, three directions of consideration of computational speed, more uncertain factor are set forth Calculation of Available Transfer Capability faster, but to use linear distribution factor method carry out online ATC calculate discuss less.

Document three " based on the available transmission capacity sensitivity analysis of direct current distribution factor " (electric power network technique was rolled up 45 pages of the 18th phases in 2006 the 30th) passes through the analysis based on the Calculation of Available Transfer Capability process of direct current distribution factor; Key restrain circuit or the situation of change of constraint section tidal current after node power changes according to the decision available transmission capacity obtain the sensitivity between available transmission capacity and the node power; This sensitivity can provide the variation tendency that node power changes the back available transmission capacity, and then is used for the available transmission capacity of concluding the business after the computing node variable power.This article has been discussed emphatically and has been utilized distribution factor correction branch road that generator is injected sensitivity of method after circuit N-1 cut-offs, but the ATC computational methods after screening technique, the generator N-1 of fault collection cut-off, the quick acquiring method of distribution factor are not specifically mentioned.

Document four " based on Calculation of Available Transfer Capability between the node of dc sensitivities method " (North China power technology 2008 No.10 the 1st page) calculates and has carried out detailed description using the linear distribution factorization method to carry out ATC; The derived computing formula of power delivery breadth coefficient, branch breaking breadth coefficient, branch breaking transmission breadth coefficient; For using the linear distribution factorization method to carry out ATC calculating the necessary technology basis is provided; But in article, use example to be merely IEEE5 node example; In computational process, do not consider the fault screening; Thereby whether can meet the demands for the large scale system computational speed and not mention, simultaneously, the ATC computational methods after cut-offfing for generator N-1 are not specifically mentioned yet.

Summary of the invention

Goal of the invention of the present invention is: a kind of online Calculation of Available Transfer Capability method is provided, can reduces amount of calculation, improve computational speed, and can improve the ATC computational accuracy of generator N-1.

To achieve these goals, the technical scheme below the present invention has taked realizes:

A kind of online Calculation of Available Transfer Capability method based on distribution factor may further comprise the steps:

1) basic section obtains, generates: from the EMS of control centre, obtain in real time or the data section under the research mode, the information of online acquisition comprises the operational mode and the measurement of grid equipment parameter, electrical network, forms the basic section that ATC calculates;

2) basic section tidal current calculates: basic section is carried out trend calculate, have only the basic section of convergence just to carry out ATC calculating, if basic section is not restrained, then provide warning information, point out initial section unreasonable, no longer carry out following calculating;

3) branch road is meritorious to the meritorious Calculation of Sensitivity of injecting of node: it is meritorious to the meritorious Sensitivity calculation of injecting of node that the B ' matrix that utilizes trend to calculate the generation of PQ decoupling method carries out branch road;

4) cut-offfing the line fault collection forms: needs are carried out generator node and the load bus (section ATC, interregional ATC can handle equally) that ATC calculates; Utilize its shortest logical path of BFS method search; Be made as fault collection A; Utilize that branch road in the step 3) is meritorious to be injected sensitivity and ask for the cut-off distribution factor of every circuit of fault collection A to all the other circuits of system node is meritorious; Distribution factor is made as fault collection B greater than the circuit of giving set threshold, the union of fault collection A and fault collection B be asked cut-off the line fault collection;

5) calculate to consider that the branch road of frequency modulation characteristic is meritorious to the meritorious sensitivity of generator: during ATC calculating generator N-1 cut-offs under, the variation of each branch road trend when needing calculating generator to cut-off, this just needs to calculate the meritorious sensitivity that generator is gained merit of branch road; When actual motion; Behind the generator outage; The generator trend is not to transfer on the balancing machine of setting; But share in many generators of system and load according to frequency modulation characteristic, so the branch road that step 3) is calculated meritorious to generator meritorious sensitivity rationally revise according to frequency modulation characteristic;

6) calculate point-to-point available transmission capacity: calculating the process of ATC between specified node, promptly is to seek the process that influences transmission capacity available bottleneck branch road between node; If supply node is A, receiving electrical nodes is B, to any transmission of electricity branch road that is moved in the system; Calculate when the power flow on it and be in when allowing the transmission capacity limit value, and specified node (A, the power variation that is allowed on B) is available transmission capacity; When considering circuit N-1, only need to concentrate circuit to cut-off one by one to the fault that obtains in the step 4), calculate its available transmission capacity respectively; Get minimum value at last, in asking for the process of ATC, must consider the energy-conservation power of maximum adjustable of generator simultaneously;

7) available transmission capacity of the important section of calculating: according to the composition of section; Automatically confirm the composition of feeder ear A ' and receiving end B ' generator; Confirm generator set A ' and energy-conservation power of maximum adjustable of B ',, calculate the power variation of permission from the section feeder ear to receiving end with reference to step 6); The power variation that at last node is injected is converted into the power variation of stable cross section, is the available transmission capacity of stable cross section;

8) available transmission capacity between the zoning: according to the definition in zone; Automatically confirm that power supply area A " and receiving electric area B " reaches the composition of interconnection between them; With reference to step 7), calculate permission power variation from regional A " to area B ", be interregional available transmission capacity.

The beneficial effect that the present invention reached:

The present invention utilizes ground state trend section, uses linear distribution factor method to realize that ATC is in line computation.When carrying out ATC in line computation, through confirming the relevant fault collection in quick supply path search and distribution factor quick calculation method, a circuit of only fault being concentrated carries out N-1 to be handled, to reach the purpose that reduces amount of calculation, raising computational speed.When the ATC that carries out generator N-1 calculates, the influence of system's frequency modulation characteristic when considering generator outage, the ATC computational accuracy of raising generator N-1.

Description of drawings

Fig. 1 is a branch breaking penalty method sketch map of the present invention.

Embodiment

In the present invention, disclosed and utilize the sensitivity information computational scheme to cut-off the method for distribution factor.In said step 4), when the ATC that considers circuit N-1 calculates, need computational scheme to cut-off influence to other circuit trend, and the variation of cut-offfing the original sensitivity number in back.And before distribution factor was cut-off in calculating, Calculation of Sensitivity had been accomplished, and like this, can utilize existing sensitivity analysis result to cut-off the calculating of distribution factor.

By the DC power flow equation:

Write formula (1) as matrix form: P=B θ (2)

In the formula (2), P--node injecting power vector;

θ--node voltage phase angle vector;

The imaginary part of B--node admittance matrix.

Write formula (2) as another kind of form: θ=B ^-1P (3)

Equally, according to the simplified condition of P-Q decomposition method, can get the branch road power flow equation and be:

$P_{\mathrm{ij}}=-B_{\mathrm{ij}}{\mathrm{\θ}}_{\mathrm{ij}}=\frac{{\mathrm{\θ}}_i-{\mathrm{\θ}}_j}{x_{\mathrm{ij}}}---\left(4\right)$

Being write formula (4) as matrix form has: P _l=B _lΦ (5)

In the formula (5), P _l--the vector that the meritorious trend of each branch road constitutes;

B _l--the diagonal matrix that each branch road admittance is formed, a way of the system of setting up departments is l, then B _lBe l rank square formation.

Φ--each branch road two ends phase angle difference vector;

If the branch node incidence matrices of network is A, A is the capable n column matrix of l, and wherein, each row is corresponding to a branch road.In the row element of branch road ij correspondence, i classifies 1, the j as and classifies-1 as, and other element all is 0.

Then have: P _l=B _lΦ=B _lA θ=B _lAB ^-1P (6)

Can get by formula (6): Δ P _l=B _lAB ^-1Δ P (7)

If S=B _lAB ^-1, Δ P is then arranged _l=S Δ P, and matrix S is the meritorious sensitivity matrix that node is injected of branch road.Certainly, in Practical Calculation, need to consider the situation of balance node.After selected balance node, need matrix B be removed balance node corresponding row and row, be made as B ' matrix; Remove the corresponding column element of balance node among the incidence matrices A, be made as A ' matrix, then sensitivity matrix becomes:

S′＝B _lA′(B′) ^-1 (8)

B ' has generated when basic section tidal current calculates, and in the Calculation of Sensitivity process, need not to form once more.And can utilize B ' matrix after the triangle decomposition by column count to the inversion process of B ' matrix, every column count only needs a former generation back substitution, thereby computational speed is very fast.

After sensitivity information calculates end, can use following method to calculate a branch road l fast and cut-off the distribution factor of cut-offfing another branch road k.

If B ' inverse of a matrix matrix is X; Cut-off the first terminal point of branch road and be respectively i, j, suppose that branch road l, k are respectively

to the sensitivity of node i, j and then can be got by formula (8):

Wherein, X _Ii, X _IjFor inverse matrix is a respective element among the X, X _lImpedance for branch road l.Similar getting:

When branch road l cut-offs, the principle of using compensation method, think between node i, the j parallel connection reactance be-X _lParallel branch, regard original system as see into equivalent network from i, j port, as shown in Figure 1, equivalent impedance X then _TWith equivalent power supply θ ₀Be respectively:

X _T＝X _ii+X _jj-X _ij-X _ji (11)

${\mathrm{\θ}}_0={\mathrm{\θ}}_i^{\left(0\right)}-{\mathrm{\θ}}_j^{\left(0\right)}=P_l^{\left(0\right)}*X_l---\left(12\right)$

The active power that flows through on the branch road l when is for ground state in the formula (12), the active power that then flows through the negative impedance branch road is:

${\mathrm{\ΔP}}_l=\frac{{\mathrm{\θ}}_0}{X_T-X_l}=\frac{X_l}{X_T-X_l}{P}_l^{\left(0\right)}---\left(13\right)$

Use has increased injection-Δ P newly in node i _l, node j has increased injection Δ P newly _lCome equivalent branch road l to cut-off influence to other branch road trend of system, when then branch road l cut-offs, the trend variation delta P of branch road k _kFor:

${\mathrm{\ΔP}}_k=-{\mathrm{\ΔP}}_l*(S_k^i-S_k^j)=-\frac{X_l}{X_T-X_l}{P}_l^{\left(0\right)}*(S_k^i-S_k^j)=-\frac{(S_k^i-S_k^j)}{\frac{X_T}{X_l}-1}{P}_l^{\left(0\right)}---\left(14\right)$

$\frac{X_T}{X_l}=\frac{X_{\mathrm{ii}}+X_{\mathrm{jj}}-X_{\mathrm{ij}}-X_{\mathrm{ji}}}{X_l}=\frac{X_{\mathrm{ii}}-X_{\mathrm{ij}}}{X_l}+\frac{X_{\mathrm{jj}}-X_{\mathrm{ji}}}{X_l}=S_l^i-S_l^j---\left(15\right)$

Formula (15) substitution formula (14) can be got:

${\mathrm{\ΔP}}_k=-\frac{(S_k^i-S_k^j)}{(S_l^i-S_l^j)-1.0}{P}_l^{\left(0\right)}=\frac{(S_k^i-S_k^j)}{1.0-(S_l^i-S_l^j)}{P}_l^{\left(0\right)}---\left(16\right)$

Branch road l cut-offs branch road k is cut-off distribution factor D _K-lBe:

Like this, according to the sensitivity information that has calculated, utilize formula (17) just can calculate of the cut-off distribution factor of arbitrary branch breaking fast to the meritorious trend of another branch road.Certainly; When being 1.0, formula (17) can't be calculated as

.In fact, this branch breaking of this situation explanation will cause system splitting.

In the present invention, the line fault collection that cut-offs that has disclosed a kind of ATC of being applied to calculating is confirmed method automatically.In said step 4), when the ATC that considers circuit N-1 calculates, need not carry out N-1 and cut-off simulation all circuits in the model, cut-off simulation and only need carry out N-1 to the tighter circuit of object association that carries out ATC calculating.When confirming related tighter sets of lines with calculating object; The present invention at first utilize the BFS decision search from supply terminals to the shortest logical path that receives electricity point; Be made as fault collection A; Calculate among the fault collection A circuit branch breaking to the distribution factor of cut-offfing of all the other circuits of system, be made as fault collection B to cut-offfing distribution factor greater than the circuit of given threshold value, the union of fault collection A and fault collection B is the line fault collection of being asked.

Automatically the step of confirming to cut-off the line fault collection is following:

1) set up 2 vector containers and a chained list, the table 1 of seeing Appendix:

Branch road structure vector container is called container 1.Comprise branch road number, branch type, branch road name and first node number, minor details period totally 5 members, be called member 1, member 2, member 3, member 4, the member 5 of container 1 respectively.

Electrical node structure vector container is called container 2.Structure vector container totally 2 members that comprise the female wire size of logic and this node connected node collection of node are called member 1, the member 2 of container 2 respectively.For the element of each container 2, the element number among the member 2 is more than or equal to 1.Corresponding electric power system notion, the electrical node of a work links to each other with one or more electrical nodes.

The searching route chained list is called chained list 1.The type of the branch road that comprise the female wire size of the female wire size of logic, father node logic of node, the logic branch road that links to each other with its parent record logic bus number, links to each other with father node and the branch road title that links to each other with father node be totally 5 members, is called member 1, member 2, member 3, member 4, the member 5 of chained list 1 respectively.

2) to basic flow data section.Closed circuits all in the model and closed transformer branch road are traveled through; These branch roads are numbered, and the branch road of each branch road number, branch type, branch road name and first node number, minor details period are stored in respectively among member 1, member 2, member 3, member 4 and the member 5 of container 1.

3) member to each branch road structure vector travels through; After finding new electrical node; Set up new container 2 elements, the member 1 that the female wire size of the logic of this node is put into container 2, and node number of this traversal branch road opposite end added among the member 2 of container 2; If find the head of this branch road or the value that the minor details period equals a certain element member 1 in the existing container 2 when traveling through other branch road, then among the member 2 with this element in the peer node adding container 2 of this traversal branch road.

4) node number of establishing supply node is a start node, and the node number that receives electrical nodes is a terminal node, and the node number of start node is changed to chained list 1 member's 1 value and member 2 value; Utilize the BFS method then; To deposit in from the nodal information the searching route that start node begins in the chained list 1, wherein, chained list 1 member 1 storage branch road peer node number; Member's 2 storage branch road local terminal node numbers; The branch road of branch road in container 1 that member 3 storage members 1 link to each other with member 2 number, the branch type of branch road in container 1 that member 4 storage members 1 link to each other with member 2, member 5 stores the branch road title of branch road in container 1 that members 1 link to each other with member 2.If can't find terminal node through this search method, then drawing supply node is not 0 conclusion in the electric island of same work, ATC result of calculation with receiving electrical nodes; If can find terminal node through this search method, then light by terminal node, seek the upper strata father node until start node, obtain from supply node to form fault collection A by chained list 1 to a supply path information that passed through by electrical nodes.

5) all circuits to fault collection A carry out other line disconnection distribution factor calculating to system, will cut-off the circuit adding fault collection B of distribution factor greater than threshold value.

6) circuit of merging fault collection A and fault collection B is removed the part that wherein repeats, and forms and cut-offs the line fault collection.

In the present invention, it is meritorious to the meritorious sensitivity computing method of generator to have disclosed a kind of branch road of considering frequency modulation characteristic.In said step 5); In the electrical network actual motion; After the generator outage or the variation of exerting oneself; The generator trend that changes not is all to transfer on the balancing machine of setting, but shares in many generators of system and load according to frequency modulation characteristic, this just need to branch road meritorious to generator the sensitivity of gaining merit rationally revise according to frequency modulation characteristic.

In system, after certain generator outage or the variation of exerting oneself, suppose that vacancy power Δ P can be by a distribution coefficient vectors=[α when power shortage Δ P appearred gaining merit in system ₁, α ₂..., α _n] ^T(n is the number of logical node in the system, and distribution coefficient satisfies ) in total system, distribute between all units, load.The choosing method of distribution coefficient α generally has: the Capacity Ratio by the unit of participate in reconciling chooses, by the merit of unit, load frequently the static characteristic coefficient choose, on average choose, choose etc. by artificial prescribed coefficient by every generator.

Setting the sensitivity correction matrix is:

$C=\left[\begin{array}{cccc}1-{\mathrm{\α}}_1& -{\mathrm{\α}}_1& \·\·\·& -{\mathrm{\α}}_1\\ -{\mathrm{\α}}_2& 1-{\mathrm{\α}}_2& \·\·\·& -{\mathrm{\α}}_2\\ .& .& .& .\\ .& .& .& .\\ .& .& .& .\\ -{\mathrm{\α}}_n& -{\mathrm{\α}}_n& \·\·\·& 1-{\mathrm{\α}}_n\end{array}\right]---\left(18\right)$

The physical significance of sensitivity correction matrix is: if on node i, increase the injecting power of a unit, then under this perturbation action, electric power system will reach a new poised state after through one section transient process.Under this state because each bus injecting power increment that the variation of system frequency really acts in the electric power system is [α ₁1-α _i-α _n] ^T

Thereby obtain the meritorious Calculation of Sensitivity formula of new branch road be: S ^M=[S 0] * C (19)

S in the formula (19) ^MBe new sensitivity matrix; Promptly on the basis of conventional sensitivity matrix, increase by a row neutral element, row that increase newly are the sensitivity of reference node in the conventional method.S ^MMiddle element

Be illustrated in the sensitivity of the meritorious meritorious injection to bus i of branch road l when considering the generator frequency modulation characteristic, its computing formula is:

α _iAccount for the proportionality coefficient of the total regulating power of system for the meritorious regulating power of bus i.The sensitivity of revising through formula (20) has considered that effectively meritorious the exerting oneself of generator regulate or when cut-offfing, the respective change of other node injection rate of system, and the result is more accurate, reasonable, approaches the actual conditions of power system operation.

In the present invention, disclosed a kind of interregional Calculation of Available Transfer Capability method.In said step 8), according to the definition in zone, confirm power supply area automatically and receive electricity composition regional and interconnection between them that calculating to the permission power variation that receives the electricity zone, can be tried to achieve interregional available transmission capacity from power supply area.

The step of carrying out interregional Calculation of Available Transfer Capability is following:

1) confirms power supply area and receive interconnection collection between the electric zone.All circuits in the Ergodic Theory, if the first stub area of a circuit belongs to power supply area respectively and receives the electricity zone, then this circuit belongs to the interconnection collection;

2) confirm the generator maximal regulated ability of power supply area.To the generator (comprising this zone boundary interconnection) of power supply area current exert oneself, EIAJ adds up, and calculates the generator maximal regulated ability of this power supply area.According to the adjustment mode of exerting oneself of appointment, increase exerting oneself of power supply area generator, reduce to receive exert oneself (or increasing the load that receives electric zone) of electric regional generator, calculate meritorious regulated quantity and the definite bottleneck equipment of allowing of each node;

3) to every circuit of interregional interconnector collection, utilize branch road meritorious to the meritorious sensitivity information that injects of node, calculate its meritorious variation after the meritorious adjusting of node, and sue for peace, can try to achieve interregional available transmission capacity.

Table 1 available transmission capacity supply path search structure of container table

The present invention is illustrated according to the preferred embodiment, should be appreciated that but the foregoing description does not limit the present invention in any form, and all employings are equal to the technical scheme that form obtained of replacement or equivalent transformation, all drop within protection scope of the present invention.

Claims (5)

1. the online Calculation of Available Transfer Capability method based on distribution factor is characterized in that, may further comprise the steps:

1) basic section obtains, generates: from the EMS of control centre, obtain in real time or the data section under the research mode; The information of online acquisition comprises the operational mode and the measurement of grid equipment parameter, electrical network, forms the basic section of electric power system Calculation of Available Transfer Capability;

2) basic section tidal current calculates: basic section is carried out trend calculate; Have only the basic section of convergence just to carry out the electric power system Calculation of Available Transfer Capability,, then provide warning information if basic section is not restrained; Point out initial section unreasonable, no longer carry out following calculating;

3) branch road is meritorious to the meritorious Calculation of Sensitivity of injecting of node: it is meritorious to the meritorious Sensitivity calculation of injecting of node that the B ' matrix that utilizes trend to calculate the generation of PQ decoupling method carries out branch road; B ' matrix is removed balance node corresponding row and row for the B matrix, and the B matrix is the imaginary part of node admittance matrix;

4) cut-offfing the line fault collection forms: the generator node and the load bus that needs are carried out the electric power system Calculation of Available Transfer Capability; Utilize its shortest logical path of BFS method search; Be made as fault collection A; Utilize that branch road in the step 3) is meritorious to be injected sensitivity and ask for the cut-off distribution factor of every circuit of fault collection A to all the other circuits of system node is meritorious; Distribution factor is made as fault collection B greater than the circuit of giving set threshold, the union of fault collection A and fault collection B be asked cut-off the line fault collection;

5) calculate to consider that the branch road of frequency modulation characteristic is meritorious to the meritorious sensitivity of generator: during electric power system available transmission capacity under calculating generator N-1 cut-offs; It is meritorious to the meritorious sensitivity of generator to calculate branch road, and the branch road that step 3) is calculated meritorious to generator meritorious sensitivity revise according to frequency modulation characteristic;

6) calculate point-to-point available transmission capacity: calculating the process of electric power system available transmission capacity between specified node, promptly is to seek the process that influences transmission capacity available bottleneck branch road between node; If supply node is A, receiving electrical nodes is B, to any transmission of electricity branch road that is moved in the system; Calculate when the power flow on it and be in when allowing the transmission capacity limit value, and specified node (A, the power variation that is allowed on B) is available transmission capacity; When considering circuit N-1; Only concentrate circuit to cut-off one by one, calculate its available transmission capacity respectively, get minimum value at last the fault that obtains in the step 4);

7) available transmission capacity of the important section of calculating: according to the composition of section; Automatically confirm the composition of feeder ear A ' and receiving end B ' generator; Confirm generator set A ' and energy-conservation power of maximum adjustable of B ',, calculate the power variation of permission from the section feeder ear to receiving end with reference to step 6); The power variation that at last node is injected is converted into the power variation of stable cross section, is the available transmission capacity of stable cross section;

8) available transmission capacity between the zoning: according to the definition in zone; Automatically confirm that power supply area A " and receiving electric area B " reaches the composition of interconnection between them; With reference to step 7), calculate permission power variation from regional A " to area B ", be interregional available transmission capacity.

2. the online Calculation of Available Transfer Capability method based on distribution factor according to claim 1 is characterized in that: in said step 4), the computational methods of utilizing existing sensitivity analysis result to cut-off distribution factor are:

Branch road l cut-offs branch road k is cut-off distribution factor D _K-lFor: $D_{k-l}=\frac{S_k^i-S_k^j}{1.0-(S_l^i-S_l^j)}---\left(17\right)$

Wherein,

is respectively branch road l, the k sensitivity to node i, j.

3. the online Calculation of Available Transfer Capability method based on distribution factor according to claim 1 is characterized in that: in said step 4), the step of confirming to cut-off the line fault collection automatically is following:

1) set up 2 vector containers and a chained list:

Branch road structure vector container is called container 1, comprises branch road number, branch type, branch road name and first node number, minor details period totally 5 members, is called member 1, member 2, member 3, member 4, the member 5 of container 1 respectively;

Electrical node structure vector container is called container 2, comprises structure vector container totally 2 members of the female wire size of logic and this node connected node collection of node, is called member 1, the member 2 of container 2 respectively;

The searching route chained list; Be called chained list 1; The type of the branch road that comprise the female wire size of the female wire size of logic, father node logic of node, the logic branch road that links to each other with its parent record logic bus number, links to each other with father node and the branch road title that links to each other with father node be totally 5 members, is called member 1, member 2, member 3, member 4, the member 5 of chained list 1 respectively;

2) to basic flow data section; Closed circuits all in the model and closed transformer branch road are traveled through; These branch roads are numbered, and the branch road of each branch road number, branch type, branch road name and first node number, minor details period are stored in respectively among member 1, member 2, member 3, member 4 and the member 5 of container 1;

3) member to each branch road structure vector travels through; After finding new electrical node; Set up new container 2 elements, the member 1 that the female wire size of the logic of this node is put into container 2, and node number of this traversal branch road opposite end added among the member 2 of container 2; If find the head of this branch road or the value that the minor details period equals a certain element member 1 in the existing container 2 when traveling through other branch road, then among the member 2 with this element in the peer node adding container 2 of this traversal branch road;

4) node number of establishing supply node is a start node; The node number that receives electrical nodes is a terminal node; The node number of start node is changed to chained list 1 member's 1 value and member 2 value, utilizes the BFS method then, will deposit in from the nodal information the searching route that start node begins in the chained list 1; Wherein, Chained list 1 member 1 storage branch road peer node number, member's 2 storage branch road local terminal node numbers, the branch road of branch road in container 1 that member 3 storage members 1 link to each other with member 2 number; The branch type of branch road in container 1 that member 4 storage members 1 link to each other with member 2; The branch road title of branch road in container 1 that member 5 storage members 1 link to each other with member 2, if can't find terminal node through this search method, then draw supply node and receive electrical nodes not on the electric island of same work, electric power system Calculation of Available Transfer Capability result is 0 conclusion; If can find terminal node through this search method, then light by terminal node, seek the upper strata father node until start node, obtain from supply node to form fault collection A by chained list 1 to a supply path information that passed through by electrical nodes;

5) all circuits to fault collection A carry out other line disconnection distribution factor calculating to system, will cut-off the circuit adding fault collection B of distribution factor greater than threshold value;

6) circuit of merging fault collection A and fault collection B is removed the part that wherein repeats, and forms and cut-offs the line fault collection.

4. the online Calculation of Available Transfer Capability method based on distribution factor according to claim 1 is characterized in that: in said step 5), to the meritorious method that meritorious sensitivity is revised according to frequency modulation characteristic to generator of branch road be:

${\left(S_l^i\right)}^M=S_l^i-\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\α}}_i{S}_l^j---\left(20\right)$

Be illustrated in the sensitivity of the meritorious meritorious injection to bus i of branch road l when considering the generator frequency modulation characteristic, α _iAccount for the proportionality coefficient of the total regulating power of system for the meritorious regulating power of bus i.

5. the online Calculation of Available Transfer Capability method based on distribution factor according to claim 1 is characterized in that: in said step 8), interregional Calculation of Available Transfer Capability method is:

1) confirm power supply area and receive interconnection collection between the electric zone, all circuits in the Ergodic Theory, if the first stub area of a circuit belongs to power supply area respectively and receives the electricity zone, then this circuit belongs to the interconnection collection;

2) confirm the generator maximal regulated ability of power supply area; To the generator of power supply area current exert oneself, EIAJ adds up; Calculate the generator maximal regulated ability of this power supply area,, increase exerting oneself of power supply area generator according to the adjustment mode of exerting oneself of appointment; Reduce to receive exerting oneself of electric regional generator, calculate meritorious regulated quantity and the definite bottleneck equipment of allowing of each node;

3) to every circuit of interregional interconnector collection, utilize branch road meritorious to the meritorious sensitivity information that injects of node, calculate its meritorious variation after the meritorious adjusting of node, and sue for peace, can try to achieve interregional available transmission capacity.

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