CN103714491A - Power grid dispatching operation order optimum sequence generation method based on risk - Google Patents

Abstract

The invention discloses a power grid dispatching operation order optimum sequence generation method based on risk. The method comprises the following steps: performing topology analysis on a power grid electrical connection graph and establishing an electrical power system spanning tree structure with a load node to be transferred being an initial node; utilizing a depth-first search method to search and access the spanning tree structure, and finding all power supply pathways, with goal nodes being power supply nodes; calculating an integrated risk index value of each power supply pathway; and comparing the integrated risk index values of initial power supply schemes, and regarding the power supply pathway corresponding to the minimum integrated risk index value as an operation sequence which enables the power grid to run in the safest state. The method helps to reduce the scheduling personnel participating in decision process, solve the problem of how to select the optimum scheme in a plurality of feasible operation schemes, and ensure a reasonable order, thereby greatly reducing the time consumed by ineffective searching, and improving the operation sequence generation speed.

Description

A kind of operation scheduling on transmission net of electric power optimal sequence generation method based on risk

Technical field

The present invention relates to field of power, particularly a kind of operation scheduling on transmission net of electric power optimal sequence generation method based on risk.

Background technology

Modern power network structure is day by day complicated, and the method for operation is varied, and the safe operation problem of electrical network is paid close attention to widely.In the operational process of electrical network, for improving power supply reliability, inevitably exist load to need to shift the situation of [1].When formulating relevant solution, staff is often from self experience and knowledge, to determining a kind of preferably power supply plan.But it,, not veritably from the structure of electrical network, is preferentially chosen all possible power supply plan, and the transfer scheme that even he formulates may cause the accident of system generation security.Therefore, there is larger subjectivity in the deterministic process of this power supply plan, has limitation.

Certainly also having some researchs to put forth effort on addresses the above problem.Document [2] has proposed to consider in scheduling operation bill system the problem that load shifts, it is first by depth-first search process, search out power supply plan likely, the thought of reconstruct Network Based again, the switching manipulation number of take minimum as objective function, take electrical network static security as constraint condition, in kinds of schemes, find best power supply plan.But it also needs to consider following problem.

(1) electrical network is being carried out in Analysis of Topological Structure process, if adopt single searching algorithm, first finding all possible power supply plans, then according to constraint condition, possibility power supply plan is being screened.The method hour can go out some satisfactory initial supply paths really in electrical network scale, but when electrical network popularization, the efficiency of whole search can be very low;

(2) it only take that switching manipulation number is minimum carries out optimizing as single goal, to searching out best power supply plan.But should be noted that, the power supply plan that meets objective function may not be unique, it possibly cannot provide the most rational result.

Summary of the invention

The invention provides a kind of operation scheduling on transmission net of electric power optimal sequence generation method based on risk, the present invention has shortened the time of expending without efficient search, has improved the speed that the sequence of operation generates, described below:

A kind of operation scheduling on transmission net of electric power optimal sequence generation method based on risk, said method comprising the steps of:

(1) electrical network electrical connection diagram is carried out to topological analysis, the load bus that the needs of take shift is start node structure electric system spanning tree structure;

(2) adopt Depth Priority Searching to search for access to spanning tree structure, finding destination node is all supply accesses of power supply node;

(3) calculate the integrated risk desired value of each supply access;

(4) by the integrated risk desired value of each initial power supply plan relatively, using the corresponding supply path of minimum integrated risk desired value as operation of power networks in the sequence of operation of safe condition.

Being operating as of the integrated risk desired value of described each supply access of calculating:

1) fault rate;

P=K×e ^C×S (1)

In formula: the failure rate of P indication equipment, K represent that scale-up factor, C represent the condition grading of coefficient of curvature, S indication equipment;

2) fault produces consequence;

(1) overload risk severity index

$\mathrm{Sev}\left(\mathrm{OverLoad}\right)=\left\{\begin{array}{cc}0& (I\≤0.8)\\ e^{(I-0.8)}-1& (I>0.8)\end{array}\right.---\left(2\right)$

In formula: I represents the electric current of the equipment of flowing through and the ratio of its rated current;

(2) low-voltage risk severity index

$\mathrm{Sev}\left(\mathrm{LowVoltage}\right)=\left\{\begin{array}{cc}0& (V\&GreaterEqual;0.9)\\ e^{(0.9-V)}-1& (V<0.9)\end{array}\right.---\left(3\right)$

In formula: V represents the voltage perunit value of bus nodes;

(3) cascading failure risk severity index

${\mathrm{Sev}}_{\mathrm{\&beta;}}\left(\mathrm{Cascading}\right)=\underset{i\&Element;M}{\mathrm{\&Sigma;}}{\mathrm{Sev}}_i\left(\mathrm{OverLoad}\right)+\underset{j\&Element;N}{\mathrm{\&Sigma;}}{\mathrm{Sev}}_j\left(\mathrm{LowVoltage}\right)---\left(4\right)$

In formula: β represents the β level of cascading failure reaction, and M is the set of all overload circuits of chain process, and N is all low-voltage bus set of chain process;

3) calculating of integrated risk value

Overload risk: $R\left(\mathrm{OverLoad}\right)=\underset{i}{\mathrm{\&Sigma;}}{P}_i\&times;\mathrm{Sev}\left(\mathrm{OverLoad}\right)---\left(5\right)$

Low-voltage risk: $R\left(\mathrm{LowVoltage}\right)=\underset{i}{\mathrm{\&Sigma;}}{P}_i\&times;\mathrm{Sev}\left(\mathrm{LowVoltage}\right)---\left(6\right)$

In above two formulas: i represents primary fault collection, P _ithe probability that represents the concentrated circuit element fault of this fault.

Cascading failure risk is:

$R\left(\mathrm{Cascading}\right)=\underset{i}{\mathrm{\&Sigma;}}\underset{\mathrm{\&beta;}=0}{\overset{K}{\mathrm{\&Sigma;}}}(R\left(\mathrm{OverLoad}\right)+R\left(\mathrm{LowVoltage}\right))---\left(7\right)$

In formula: i represents primary fault collection, β represents the β level of cascading failure reaction, and K represents maximum cascading failure progression;

Integrated risk desired value is that the weighted stacking of each factor risk value is expressed as:

Risk=α ₁R(OverLoad)+α ₂R(LowVoltage)+α ₃R(Cascading) (8)

α wherein ₁, α ₂, α ₃weights for all types of risk factors, meet α ₁+ α ₂+ α ₃=1.

The beneficial effect of technical scheme provided by the invention is:

(1) in optimum operation sequence generative process, taken into account the requirement of power system economy and security, introduced the static security evaluation index based on risk, reduced the process of dispatcher's participative decision making, and solved how in multiple feasible operation scheme, to carry out problem preferentially, guaranteed the rationality of making out an invoice.

(2) electric system spanning tree is being carried out in the process of depth-first search, adopted heuristic technology of prunning branches, form the security analysis parallel with operation steps, greatly shortened the time of expending without efficient search, improved the speed that the sequence of operation generates.

Accompanying drawing explanation

Fig. 1 is that optimal sequence generates step;

Fig. 2 is the calculation flow chart of power grid cascading failure risk desired value;

Fig. 3 is the structural drawing of somewhere part electrical network.

Embodiment

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing, embodiment of the present invention is described further in detail.

When the present invention needs to consider load to shift in operation of power networks maintenance process, utilize Depth Priority Searching ^[3]electrical network is carried out to Analysis of Topological Structure, introduce heuristic technology of prunning branches ^[4]eliminate in time the invalid transfer path that does not meet operation of power networks requirement, and can cause the operation of topological structure of electric variation to carry out Security Checking to each, obtain some initial supply paths that meet operation of power networks requirement.Initial supply path is being carried out when preferred, using the Contingency Analysis of Power Systems based on Risk Theory ^[5]method, the comparison decision by electric network synthetic risk indicator value generates optimum operation sequence, has guaranteed the uniqueness of formation sequence and the versatility of generting machanism, its whole generative process as shown in Figure 1.

101: electrical network electrical connection diagram is carried out to topological analysis, and the load bus that the needs of take shift is start node structure electric system spanning tree structure;

102: adopt Depth Priority Searching to search for access to spanning tree structure, finding destination node is all supply accesses of power supply node;

For fast searching is to all supply accesses, finding destination node is all supply accesses of power supply node, adopt Depth Priority Searching to search for access to spanning tree, in conjunction with didactic technology of prunning branches, getting rid of in time those does not meet power system static security constraint, violates the basic operations specification of electric system, or economy do not reach the operation of set standard, simplified search procedure, greatly improved the efficiency of search.

The beta pruning principle that this method adopts, comprises macroscopical requirement of economy and two aspects of security of operation of power networks.

From economy criterion, consider, if while searching for to certain node, the number of switches that the supply path that this search path represents need to draw, close too much (is set according to the needs in practical application, during specific implementation, the embodiment of the present invention does not limit this), or when the load of loss surpasses expection limit, think that this supply path operates the economic cost of paying excessive, need carry out beta pruning optimization, therefore can cut off by this node and with undershoot road, avoid without efficient search, then start new depth-first search process.Until while accessing to destination node place, the operation of this searching route representative beta pruning can not occur, can think that this supply path is to meet the initial power supply plan that electrical network economy requires.

From the viewpoint of security criterion, search is during to certain node, whether operation corresponding to judgement this node of access can cause network topology structure to change (this operation can cause the variation of transmission line of electricity or running state of transformer etc.), if can cause variation, carry out the verification of electrical network static security and the verification of electric system fundamental norms, during any verification failure, can in same one-level node, cut off this node, re-start depth-first search next time, avoid proceeding without efficient search; If can not cause variation, by original search principle, continue access next node.If accessed to destination node place, when all operations all meet verification condition in this searching route, can think that the operation of this supply path meets the requirement of security, this supply path can be used as the initial power supply plan that meets electric network security.

Beta pruning principle according to above-mentioned economy and security, when depth-first search process only has the criterion that simultaneously meets economy and security, can obtain the several initial power supply plan that meets operation of power networks requirement.

103: the integrated risk desired value of calculating each supply access;

Power system security appraisal procedure based on risk, probability and serious consequence thereof that while having taken into account system stable operation, fault occurs.The present invention introduces the Contingency Analysis of Power Systems based on risk in the decision process of the best tickets sample of scheduling ticket, has guaranteed to generate the uniqueness of optimal sequence, has reflected the security of operation state of the electrical network after the sequence of operation is carried out simultaneously also more scientificly.In addition, in order to obtain more scientific rational risk assessment index, the integrated risk evaluation index that the present invention adopts has not only comprised overload risk indicator, low-voltage risk indicator, has also comprised cascading failure risk indicator.By the integrated risk desired value of each initial power supply plan relatively, optimize one and can guarantee that operation of power networks is in the sequence of operation of safe condition.

In security analysis of electric power system, risk is defined as: fault rate and fault produce the product of consequence.

1) fault rate;

Fault rate is the failure rate of electrical equipment, and it is an important indicator that characterizes Power System Reliability.The fault rate that this method is set is based on equipment state methods of marking ^[6]determine.

Research shows, between equipment state scoring and failure rate, has following exponential relationship

P=K×e ^C×S (1)

In formula: the failure rate of P indication equipment, K represent that scale-up factor, C represent the condition grading of coefficient of curvature, S indication equipment.

Therefore, only need 2 years above device history condition grading S and the value of equipment failure rate P, just can draw the size of parameter K, C, then can realize the reckoning of equipment failure rate under known state scoring.

2) fault produces consequence

(1) overload risk severity index

Equipment overload risk refers in system when a certain element fault maybe needs to overhaul, and causes the redistributing of trend of electrical network, and the size of current through line electric current may surpass its ratings, cause system risk.According to operations staff's experience, determine: the formula of system overload severity Sev (OverLoad) is:

$\mathrm{Sev}\left(\mathrm{OverLoad}\right)=\left\{\begin{array}{cc}0& (I\&le;0.8)\\ e^{(I-0.8)}-1& (I>0.8)\end{array}\right.---\left(2\right)$

In formula: I represents the electric current of the equipment of flowing through and the ratio of its rated current.

(2) low-voltage risk severity index

Low-voltage risk reflection be system equipment when breaking down or overhauling, busbar voltage drops to the risk to a certain degree causing afterwards.Low-voltage seriousness is mainly to be determined by the voltage swing of bus.According to operations staff's experience, determine: the formula of system low-voltage severity Sev (LowVoltage) is

$\mathrm{Sev}\left(\mathrm{LowVoltage}\right)=\left\{\begin{array}{cc}0& (V\&GreaterEqual;0.9)\\ e^{(0.9-V)}-1& (V<0.9)\end{array}\right.---\left(3\right)$

In formula: V represents the voltage perunit value of bus nodes.

(3) cascading failure risk severity index

What the present invention mainly considered is the cascading failure that system overload and low-voltage cause, and its risk indicator is by the overload value-at-risk in each stage of chain reaction and low-voltage value-at-risk is cumulative obtains.Therefore, obtain cascading failure primary risk seriousness Sev _β(Cascading) computing formula is:

${\mathrm{Sev}}_{\mathrm{\&beta;}}\left(\mathrm{Cascading}\right)=\underset{i\&Element;M}{\mathrm{\&Sigma;}}{\mathrm{Sev}}_i\left(\mathrm{OverLoad}\right)+\underset{j\&Element;N}{\mathrm{\&Sigma;}}{\mathrm{Sev}}_j\left(\mathrm{LowVoltage}\right)---\left(4\right)$

In formula: β represents the β level of cascading failure reaction, and M is the set of all overload circuits of chain process, and N is all low-voltage bus set of chain process, Sev _i(OverLoad), Sev _j(Low Voltage) represents respectively the severity value of chain process overload, low-voltage.

3) calculating of integrated risk value

The computing formula that can be obtained electrical network overload risk, low-voltage risk size by formula (1) is expressed as

Overload risk: $R\left(\mathrm{OverLoad}\right)=\underset{i}{\mathrm{\&Sigma;}}{P}_i\&times;\mathrm{Sev}\left(\mathrm{OverLoad}\right)---\left(5\right)$

Low-voltage risk: $R\left(\mathrm{LowVoltage}\right)=\underset{i}{\mathrm{\&Sigma;}}{P}_i\&times;\mathrm{Sev}\left(\mathrm{LowVoltage}\right)---\left(6\right)$

In above two formulas: i represents primary fault collection, P _ithe probability that represents the concentrated circuit element fault of this fault.

For cascading failure value-at-risk, its detailed computation process is as follows:

Primary fault integrates the set as uniline fault, choose a certain faulty line hypothesis of stopping transport, it is β=1 that chain progression is set, and the electrical network after this line outage is carried out to trend calculating, obtain the value-at-risk of electrical network overload, low-voltage, the cascading failure value-at-risk that additive value is this grade.According to calculation of tidal current, judge the maximal value of the low-voltage value-at-risk of load buses all in electrical network or generator node, whether be greater than certain limit value (Definition Principles of this limit value of default, while representing that in electrical network, node arrives this low-voltage, system protection can move and excise load or generator), if it is in topological structure, remove this node and connected circuit, chain progression β adds 1; If not, continue the original trend result of judgement.It is (the same that trend judges whether to exist the maximal value of certain circuit overload to be greater than limit value; the limit value of adjusting in the time of can causing overload protection action); if it is this circuit of tangent line; chain progression β adds 1; if otherwise represent under this electrical network condition not can initiating system protection action; then there will be no the generation of cascade phenomenon, can simulated failure concentrate the chain reaction situation of next line fault.In said process, if while there is cutting load, generator or circuit, chain progression can increase by 1, represent that chain process continues,, before not reaching maximum chain degree of depth K, proceed the trend of electrical network under this progression and calculate, and it is chain to adopt same standard to determine whether that meeting continues, until chain during to K level, stop this fault collection line outage simulation process, calculate the chain value-at-risk under this primary fault.Continue to judge the situation simulation of next line fault, until all faults concentrate the uniline simulation of stopping transport to finish, then by cascading failure value-at-risk algebraic addition under all initial uniline faults, get final product to obtain the cascading failure value-at-risk of this electrical network.In addition, in said process, if there is situation about not restraining when trend is calculated, also represent that system collapses, think that the severity of fault is 1, calculate the Risk Theory maximal value of this electrical network.The concrete calculation process of power grid cascading failure risk value, as shown in Figure 2.

On the whole, cascading failure Risk Calculation formula can be expressed as:

$R\left(\mathrm{Cascading}\right)=\underset{i}{\mathrm{\&Sigma;}}\underset{\mathrm{\&beta;}=0}{\overset{K}{\mathrm{\&Sigma;}}}(R\left(\mathrm{OverLoad}\right)+R\left(\mathrm{LowVoltage}\right))---\left(7\right)$

In formula: i represents primary fault collection, β represents the β level of cascading failure reaction, and K represents maximum cascading failure progression.

Integrated risk desired value is the weighted stacking of each factor risk value, and the computing formula of integrated risk value can be expressed as

Risk=α ₁R(OverLoad)+α ₂R(LowVoltage)+α ₃R(Cascading) (8)

α wherein ₁, α ₂, α ₃weights for all types of risk factors, meet α ₁+ α ₂+ α ₃=1.Relevant weights carry out selected and adjustment flexibly by dispatcher according to the practical operation situation of local power grid.

104: by the integrated risk desired value of each initial power supply plan relatively, using the corresponding supply path of minimum integrated risk desired value as operation of power networks in the sequence of operation of safe condition.

With concrete example, verify the feasibility of this method below, described below:

Somewhere part configuration of power network as shown in Figure 3.With the line maintenance under two kinds of different situations, be operating as example and illustrate that the present invention is put forward the rationality of sequence of operation generation strategy.

Situation one: when maintenance circuit exists extension wire

Operation task: circuit Zhang Baiyi line turns maintenance by operation, its optimal sequence generative process is as follows.

From topological structure of electric, adopt depth-first search mode, to obtain all possible paths from load bus 6 to power supply node 1 or 2.The supply path that does not adopt technology of prunning branches to search is as shown in table 1.

The supply path that table 1 does not adopt technology of prunning branches to search

From security requirement aspect, consider to carry out beta pruning.First can not there is reverse power supply in system, and node 6 is as load bus, if the next node searching is 9, represents that electric current can flow to node 6 from node 9, and the basic service requirement of the system that obviously do not meet, is got rid of.Therefore, from node 9, carry out beta pruning process, no longer continue search, but be back to last node 6, according to depth-first search principle, continue other node of access, in form, all intended paths of scheme 9～16 can not continued to consider.Secondly, static security analysis is found in real time, when node searching is during according to path 6->3->4->2, can there is low-voltage and overladen phenomenon in system, do not meet electrical network Static Security Constraints, so the represented supply path of scheme 6 is not paid attention to yet.

From electrical network economy requirement aspect.Operating switch number can not be too many, otherwise it is excessive to cause overhauling task economic cost.Therefore, must get rid of the feasible power supply plan that those operating switch numbers surpass desired value, therefore exclusion program 2,3,4,7,8.

Residue possible path according to after electrical network economy and security screening and filtering, only has two schemes as shown in table 2.

The satisfactory supply path of table 2

Supply path	Operating switch number	Supply path from load to power supply
			1	4	6->2
2	3	6->3->1

Supply path 1 represents to need the load that shifts directly by standby and column line---the white two wires power supply of the Zhang Baiyi line overhauling.Supply path 2 represents by closed scape white line, then through in running status defend scape one line, from defending the country, becoming load bus 6 provides power path.

Inspecting state electrical network after these two kinds of supply paths are carried out carries out primary fault hypothesis, sets up primary fault collection.Simulated failure concentrates a certain circuit to disconnect, and obtains the value-at-risk of overload, low-voltage and cascading failure of two schemes through tidal current analysis process repeatedly respectively as shown in table 3, table 4.

1 overload of table 3 scheme, low-voltage and cascading failure value-at-risk

Primary fault	Overload risk	Low-voltage risk	Cascading failure risk
				Defend scape one line	0.0959	0.0178	0.1455
Scape occasion line	0.0028	0.0014	0.0041
				Scape roc line	0.0083	0.0021	0.0104
White roc line	0.2354	0.0326	0.3013
				Open yellow line	0.5371	0.0266	0.5711
Yellow occasion line	0.0000	0.0067	0.0067
				Open white two wires	0.1461	0.0133	0.8800

2 overloads of table 4 scheme, low-voltage and cascading failure value-at-risk

Primary fault	Overload risk	Low-voltage risk	Chain reaction risk
				Defend scape one line	1.0329	0.0080	2.3119
Scape occasion line	0.0000	0.0013	0.0013
				Scape roc line	0.0083	0.0028	0.0111
White roc line	0.0114	0.0008	0.0194
				Open yellow line	0.1327	0.0221	0.1558
Yellow occasion line	0.0000	0.0067	0.0067
				Scape white line	0.1070	0.0023	0.7727

The calculating of the various risks value of electrical network is the algebraically stack that fault is concentrated all primary fault value-at-risks.When calculating integrated risk, three class risk indicators are balanced to be considered, in integrated risk value calculating formula, α 1, α 2, the equal value of α 3 are 1/3.Each value-at-risk that obtains supply path 1,2 is as shown in table 5.

Table 5 scheme 1 and scheme 2 value-at-risks

Scheme	Overload	Low-voltage	Cascading failure	Integrated risk
					1	1.0013	0.0863	1.9191	1.0022
2	1.2923	0.0512	3.2789	1.5408

From integrated risk index, can find out, the value-at-risk of supply path 1 is less than the value-at-risk in path 2, think that the first transfer path more meets the requirement of security of system comparatively speaking, certainly, article one, the switch number of path action required is than second transfer path many one, and the complexity of operation is slightly high.Consider the principle that power system security is preferential, the optimum operation sequence optimizing through generation strategy of the present invention is by disconnection, to transfer the white two wires in stand-by state to operation, replaces maintenance circuit to open white field work.

The process of this line maintenance is the transfer reasoning process when there is extension wire between two nodes.From field operation experiences, if certain circuit will overhaul, and while there is extension wire in this circuit, is all generally temporarily to substitute by dropping into extension wire the line powering normally moving, and the optimum operation sequence that decision-making obtains also just in time meets reality.

Situation two: when maintenance circuit does not exist extension wire

Operation task: circuit scape roc line transfers maintenance to by operation.

Because scape roc line does not have standby circuit, need to go for best supply access by closed other circuit.

In like manner, in depth-first search process, in conjunction with beta pruning optimisation technique, get rid of undesirable possible path, obtain two kinds of alternativess as shown in table 6.

The satisfactory supply path of table 6

Scheme	Operating switch number	Supply path
			1	2	8->9->6->2
2	3	8->9->6->3->1

The load that scheme 1 finger roc exhibition becomes does not need to carry out any jump operation, can directly power through existing path Zhang Baiyi line.Scheme 2 represents that the load that roc exhibition becomes not only becomes power supply by Zhang Guizhuan, and through scape white line, Wei Jing mono-line, becomes power supply by defending the country simultaneously, realizes dual power supply.

After scheme 1,2 is carried out, the electrical network of inspecting state is analyzed, and carries out primary fault hypothesis, obtains overload, low-voltage and cascading failure value-at-risk as shown in table 7, table 8.

1 overload of table 7 scheme, low-voltage and cascading failure value-at-risk

Primary fault	Overload risk	Low-voltage risk	Chain reaction risk
				Defend scape one line	0.4069	0.0501	0.4997
Scape occasion line	0.0049	0.0013	0.0062
				Zhang Baiyi line	0.3778	0.3778	0.7556
White roc line	0.3318	0.3318	0.6636
				Open yellow line	0.1374	0.0221	0.1669
Yellow occasion line	0.0030	0.0067	0.0096

2 overloads of table 8 scheme, low-voltage and cascading failure value-at-risk

Primary fault	Overload risk	Low-voltage risk	Chain reaction risk
				Defend scape one line	0.0122	0.0121	0.0321
Scape occasion line	0.0049	0.0013	0.0062
				Zhang Baiyi line	0.0072	0.0024	0.0097
White roc line	0.3981	0.3981	0.7962
				Open yellow line	0.1433	0.0221	0.1726
Yellow occasion line	0.0029	0.0067	0.0096
				Scape white line	0.0064	0.0016	0.0080

In integrated risk value computing formula, all types of risk weights also equal value are 1/3, and each value-at-risk that obtains scheme 1,2 is as shown in table 9.

Table 9 scheme 1 and scheme 2 value-at-risks

Scheme	Overload	Low-voltage	Cascading failure	Integrated risk
					1	1.2618	0.7898	2.1016	1.3844
2	0.5750	0.4443	1.0344	0.6846

Visible first scheme, by the scape white line in off-state is transferred to running status, the load of realizing roc exhibition change is become the scheme of dual power supply by the change of defending the country, Zhang Guizhuan, and power grid risk value is less, and reliability is higher.Reality is, if certain load is powered by dual power supply, power supply reliability can improve greatly, and this has also proved the rationality of the generation strategy of putting forward.

List of references

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[3] Lin Shangyuan. the depth-first traversal intelligent analysis of figure and realization [J]. the Journal of Hainan University: natural science edition, 2005,23 (2): 150-157

[4]Malerba D,Semeraro G,Esposito F.Choosing the best pruned decision tree:a matter of bias[A].Proc5th Italian Workshop on Machine Learning[C].Parma:University of Parma,1994.33-37

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It will be appreciated by those skilled in the art that accompanying drawing is the schematic diagram of a preferred embodiment, the invention described above embodiment sequence number, just to describing, does not represent the quality of embodiment.

The foregoing is only preferred embodiment of the present invention, in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (2)

1. the operation scheduling on transmission net of electric power optimal sequence generation method based on risk, is characterized in that, said method comprising the steps of:

(1) electrical network electrical connection diagram is carried out to topological analysis, the load bus that the needs of take shift is start node structure electric system spanning tree structure;

(2) adopt Depth Priority Searching to search for access to spanning tree structure, finding destination node is all supply accesses of power supply node;

(3) calculate the integrated risk desired value of each supply access;

(4) by the integrated risk desired value of each initial power supply plan relatively, using the corresponding supply path of minimum integrated risk desired value as operation of power networks in the sequence of operation of safe condition.

2. a kind of operation scheduling on transmission net of electric power optimal sequence generation method based on risk according to claim 1, is characterized in that, being operating as of the integrated risk desired value of described each supply access of calculating:

1) fault rate;

P=K×e ^C×S (1)

In formula: the failure rate of P indication equipment, K represent that scale-up factor, C represent the condition grading of coefficient of curvature, S indication equipment;

2) fault produces consequence;

(1) overload risk severity index

$\mathrm{Sev}\left(\mathrm{OverLoad}\right)=\left\{\begin{array}{cc}0& (I^{\&prime;}\&le;0.8)\\ e^{(I-0.8)}-1& (I^{\&prime;}>0.8)\end{array}\right.---\left(2\right)$

In formula: I ' represents to flow through the electric current of equipment and the ratio of its rated current;

(2) low-voltage risk severity index

$\mathrm{Sev}\left(\mathrm{LowVoltage}\right)=\left\{\begin{array}{cc}0& (U_{*}\&GreaterEqual;0.9)\\ e^{(0.9-U_{*})}-1& (U_{*}<0.9)\end{array}\right.---\left(3\right)$

In formula: U _*the voltage perunit value that represents bus nodes;

(3) cascading failure risk severity index

${\mathrm{Sev}}_{\mathrm{\&beta;}}\left(\mathrm{Cascading}\right)=\underset{i\&Element;M}{\mathrm{\&Sigma;}}{\mathrm{Sev}}_i\left(\mathrm{OverLoad}\right)+\underset{j\&Element;N}{\mathrm{\&Sigma;}}{\mathrm{Sev}}_j\left(\mathrm{LowVoltage}\right)---\left(4\right)$

In formula: β represents the β level of cascading failure reaction, and M is the set of all overload circuits of chain process, and N is all low-voltage bus set of chain process;

3) calculating of integrated risk value

Overload risk: $R\left(\mathrm{OverLoad}\right)=\underset{i}{\mathrm{\&Sigma;}}{P}_i\&times;\mathrm{Sev}\left(\mathrm{OverLoad}\right)---\left(5\right)$

Low-voltage risk: $R\left(\mathrm{LowVoltage}\right)=\underset{i}{\mathrm{\&Sigma;}}{P}_i\&times;\mathrm{Sev}\left(\mathrm{LowVoltage}\right)---\left(6\right)$

In above two formulas: i represents primary fault collection, P _ithe probability that represents the concentrated circuit element fault of this fault.

Cascading failure risk is:

$R\left(\mathrm{Cascading}\right)=\underset{i}{\mathrm{\&Sigma;}}\underset{\mathrm{\&beta;}=0}{\overset{K}{\mathrm{\&Sigma;}}}(R\left(\mathrm{OverLoad}\right)+R\left(\mathrm{LowVoltage}\right))---\left(7\right)$

In formula: i represents primary fault collection, β represents the β level of cascading failure reaction, and K represents maximum cascading failure progression;

Integrated risk desired value is that the weighted stacking of each factor risk value is expressed as:

Risk=α ₁r (OverLoad)+α ₂r (LowVoltage)+α ₃r (Cascading) (8) is α wherein ₁, α ₂, α ₃weights for all types of risk factors, meet α ₁+ α ₂+ α ₃=1.

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