CN112290547A - Power transmission network line power flow out-of-limit solving method and equipment based on network reconstruction - Google Patents

Power transmission network line power flow out-of-limit solving method and equipment based on network reconstruction Download PDF

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CN112290547A
CN112290547A CN202011194985.8A CN202011194985A CN112290547A CN 112290547 A CN112290547 A CN 112290547A CN 202011194985 A CN202011194985 A CN 202011194985A CN 112290547 A CN112290547 A CN 112290547A
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张应灵
徐郑崎
韩晔
郑立玮
赖永生
李江山
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State Grid Fujian Electric Power Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/04—Circuit arrangements for ac mains or ac distribution networks for connecting networks of the same frequency but supplied from different sources
    • H02J3/06—Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/466—Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2111/00—Details relating to CAD techniques
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    • G—PHYSICS
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    • G06F—ELECTRIC DIGITAL DATA PROCESSING
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    • G06F2111/06—Multi-objective optimisation, e.g. Pareto optimisation using simulated annealing [SA], ant colony algorithms or genetic algorithms [GA]
    • G—PHYSICS
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    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/04—Power grid distribution networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/10—Power transmission or distribution systems management focussing at grid-level, e.g. load flow analysis, node profile computation, meshed network optimisation, active network management or spinning reserve management
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/40—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation wherein a plurality of decentralised, dispersed or local energy generation technologies are operated simultaneously
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
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Abstract

The invention relates to a power transmission network line power flow out-of-limit solving method based on network reconstruction, which comprises the following steps: and establishing a first mathematical model based on the direct current power flow equation, wherein the first mathematical model consists of an objective function and a first constraint condition. And establishing a second mathematical model based on the alternating current power flow equation, wherein the second mathematical model consists of an objective function and a second constraint condition. And solving the first mathematical model by a branch-and-bound method to obtain the optimal solution of the first mathematical model. And taking the optimal solution as an initial solution of the second mathematical model, and solving the second mathematical model by a primal-dual interior point method to obtain the optimal solution of the second mathematical model, wherein the optimal solution of the second mathematical model is used for solving the problem of power flow out-of-limit and comprises a plurality of power transmission lines needing to be disconnected.

Description

Power transmission network line power flow out-of-limit solving method and equipment based on network reconstruction
Technical Field
The invention relates to a power transmission network line power flow out-of-limit solving method and equipment based on network reconstruction, and belongs to the field of power network automation.
Background
The network structure of the transmission network is basically determined during the planning period of the power network. It is also difficult to change the network structure of the grid by changing the electrical equipment during construction and operation of the grid. The transmission line can be opened or closed to reduce line flow only when equipment maintenance or shutdown is required.
The network reconstruction means that the operation state of the power transmission line is changed by selecting the combination state of the section switch and the interconnection switch on the premise of meeting various constraint conditions of the power network, so that the topological structure of the power network is changed. Through network reconstruction, network resources are reintegrated, new cost does not need to be added, and the safety, reliability and economy of the power system can be improved only by depending on the existing scale of the power transmission network. In addition, the network reconfiguration changes the topological structure and the power flow distribution of the system, so the network reconfiguration plays an important role in the aspects of reducing line overload and the like.
The power flow out-of-limit means: the voltage of the transmission network bus, the branch current or the power exceeds the rated value, so that the line is overloaded, and the problems of equipment damage, power failure and the like are caused. The mathematical model for eliminating the power flow out-of-limit through the power transmission network reconstruction mode comprises the following two types: the mathematical model based on the direct current power flow equation and the mathematical model based on the alternating current power flow equation. The former can be converted into a mixed global programming (MIP) problem to solve, but the quality of a relaxation solution of the MIP problem has a remarkable influence on the solving efficiency of the model, and the solved optimal solution is often different from the optimal solution of the actual problem. The latter is a set of nonlinear complex equations, which are generally solved by adopting an iterative method and a heuristic method, but the convergence requirement is high. More descriptions of the two mathematical models can be found in the literature "review and prospect of power grid structure optimization problem research".
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a power transmission network line power flow out-of-limit solving method and equipment based on network reconstruction, and the method and equipment can effectively solve the problem of line power flow out-of-limit by combining the advantages of two mathematical models and can also carry out emergency treatment on the faults of a power transmission network.
The technical scheme of the invention is as follows:
the first technical scheme is as follows:
a power transmission network line power flow out-of-limit solving method based on network reconstruction comprises the following steps:
establishing a first mathematical model based on a direct current power flow equation, wherein the first mathematical model consists of an objective function and a first constraint condition; establishing a second mathematical model based on the alternating current power flow equation, wherein the second mathematical model consists of an objective function and a second constraint condition; the method comprises the following steps:
s1, establishing an objective function: constructing a target function with the aim of adjusting the minimum number of the transmission lines, the minimum active output cost of the set and the minimum load shedding cost; s2, establishing a first constraint condition and a second constraint condition: establishing a candidate set of disconnectable transmission lines consisting of hot standby transmission lines and operating transmission lines according to the line disconnection distribution factors; respectively determining a first constraint condition and a second constraint condition according to the candidate set of the disconnectable power transmission line;
solving the first mathematical model by a branch-and-bound method to obtain an optimal solution of the first mathematical model; and taking the optimal solution as an initial solution of the second mathematical model, and solving the second mathematical model by a primal-dual interior point method to obtain the optimal solution of the second mathematical model, wherein the optimal solution of the second mathematical model is used for solving the problem of power flow out-of-limit and comprises a plurality of power transmission lines needing to be disconnected.
Further, the objective function is:
Figure BDA0002753767020000031
wherein i and j represent nodes at two ends of the transmission line ij respectively; o isijRepresenting the operating state of the transmission line ij: o isijWhen 0 denotes transmission line operation, OijWhen the value is 1, the power transmission line is interrupted; l isonRepresenting all hot standby transmission lines in the disconnectable transmission line candidate set; l isoffRepresenting all the operating transmission lines in the disconnectable transmission line candidate set; sGRepresenting a generator node set; sLRepresenting a set of all load nodes in the power transmission network; wGiExpressing the weight of unit output of the adjusting unit;
Figure BDA0002753767020000032
representing the active output of the generator set in an initial state; pGiRepresenting the active output of the generator set after iterative computation updating; wLiA weight representing an adjustment unit load amount; rLiRepresenting the load shedding rate of a node i in the power transmission network; pLiIndicating the magnitude of the load.
Further, according to the line disconnection distribution factor, the step of establishing the disconnectable power transmission line candidate set is as follows:
establishing a candidate set of the disconnectable power transmission line with an initial state as an empty set;
for hot standby transmission lines, if a certain hot standby transmission line can reduce tidal current overload when put into operation, adding the line into the candidate set of the disconnectable transmission lines;
for the power transmission lines in operation, if the power transmission line in operation is disconnected and the tidal current overload can be reduced, adding the line into the candidate set of the power transmission lines which can be disconnected;
respectively calculating the line breaking distribution factor of each line in the candidate set of the breakable power transmission lines;
sorting the lines in the candidate set of the disconnectable power transmission lines according to the absolute values of the line disconnection distribution factors to obtain the ranking of each line; lines ranked below a threshold are deleted.
Further, according to the candidate set of the disconnectable power transmission line, determining a first constraint condition as follows:
Figure BDA0002753767020000041
Figure BDA0002753767020000042
Figure BDA0002753767020000043
Pijmax(Oij-1)≤Pij≤Pijmax(1-Oij),(i,j)∈Lon∪Loff
Figure BDA0002753767020000044
Figure BDA0002753767020000045
Figure BDA0002753767020000046
wherein the content of the first and second substances,
Figure BDA0002753767020000047
and
Figure BDA0002753767020000048
respectively representing the upper limit and the lower limit of the reactive output of the generator; pGiIndicating generator unit activityForce is exerted; pijRepresenting the active power flow of the transmission line ij; sNRepresenting a set of all generator nodes in the transmission grid; m is a sufficiently large positive number; x is the number ofijRepresenting an impedance parameter of the transmission line ij; thetaiRepresents the phase angle of node i; l represents the set of all transmission lines in the transmission network; j denotes the maximum number of line state adjustments.
Further, according to the candidate set of the disconnectable power transmission line, determining a second constraint condition as follows:
Figure BDA0002753767020000049
Figure BDA0002753767020000051
Figure BDA0002753767020000052
Figure BDA0002753767020000053
Figure BDA0002753767020000054
Figure BDA0002753767020000055
Figure BDA0002753767020000056
Figure BDA0002753767020000057
Figure BDA0002753767020000058
Figure BDA0002753767020000059
wherein the content of the first and second substances,
Figure BDA00027537670200000510
and
Figure BDA00027537670200000511
respectively representing the upper limit and the lower limit of the reactive output of the generator; n represents all node sets of the power transmission network; v. ofnRepresenting the voltage amplitude of node n in the transmission network;
Figure BDA00027537670200000512
and
Figure BDA00027537670200000513
respectively representing the upper limit and the lower limit of the voltage of the node n;
Figure BDA00027537670200000514
and
Figure BDA00027537670200000515
respectively representing the upper limit and the lower limit of the phase angle of the node n; qijRepresenting the reactive power flow of the transmission line ij; sijRepresenting the apparent power flow of the transmission line ij; qLiRepresenting the reactive power load size of the node; gijAnd bijRespectively representing the conductance and susceptance of the power transmission line ij; v. ofi、vjRespectively representing voltage amplitudes of nodes i and j at two ends of the power transmission line ij; qGiAnd the reactive output of the generator set after the network reconstruction is represented.
The second technical scheme is as follows:
a grid line power flow violation solving device based on network reconfiguration, comprising a memory and a processor, the memory storing instructions adapted to be loaded by the processor and to perform the steps of:
establishing a first mathematical model based on a direct current power flow equation, wherein the first mathematical model consists of an objective function and a first constraint condition; establishing a second mathematical model based on the alternating current power flow equation, wherein the second mathematical model consists of an objective function and a second constraint condition; the method comprises the following steps:
s1, establishing an objective function: constructing a target function with the aim of adjusting the minimum number of the transmission lines, the minimum active output cost of the set and the minimum load shedding cost; s2, establishing a first constraint condition and a second constraint condition: establishing a candidate set of disconnectable transmission lines consisting of hot standby transmission lines and operating transmission lines according to the line disconnection distribution factors; respectively determining a first constraint condition and a second constraint condition according to the candidate set of the disconnectable power transmission line;
solving the first mathematical model by a branch-and-bound method to obtain an optimal solution of the first mathematical model; and taking the optimal solution as an initial solution of the second mathematical model, and solving the second mathematical model by a primal-dual interior point method to obtain the optimal solution of the second mathematical model, wherein the optimal solution of the second mathematical model is used for solving the problem of power flow out-of-limit and comprises a plurality of power transmission lines needing to be disconnected.
Further, the objective function is:
Figure BDA0002753767020000061
wherein i and j represent nodes at two ends of the transmission line ij respectively; o isijRepresenting the operating state of the transmission line ij: o isijWhen 0 denotes transmission line operation, OijWhen the value is 1, the power transmission line is interrupted; l isonRepresenting all hot standby transmission lines in the disconnectable transmission line candidate set; l isoffRepresenting all the operating transmission lines in the disconnectable transmission line candidate set; sGRepresenting a generator node set; sLRepresenting a set of all load nodes in the power transmission network; wGiExpressing the weight of unit output of the adjusting unit;
Figure BDA0002753767020000062
representing the active output of the generator set in an initial state; pGiRepresenting the active output of the generator set after iterative computation updating; wLiA weight representing an adjustment unit load amount; rLiRepresenting the load shedding rate of a node i in the power transmission network; pLiIndicating the magnitude of the load.
Further, according to the line disconnection distribution factor, the step of establishing the disconnectable power transmission line candidate set is as follows:
establishing a candidate set of the disconnectable power transmission line with an initial state as an empty set;
for hot standby transmission lines, if a certain hot standby transmission line can reduce tidal current overload when put into operation, adding the line into the candidate set of the disconnectable transmission lines;
for the power transmission lines in operation, if the power transmission line in operation is disconnected and the tidal current overload can be reduced, adding the line into the candidate set of the power transmission lines which can be disconnected;
respectively calculating the line breaking distribution factor of each line in the candidate set of the breakable power transmission lines;
sorting the lines in the candidate set of the disconnectable power transmission lines according to the absolute values of the line disconnection distribution factors to obtain the ranking of each line; lines ranked below a threshold are deleted.
Further, according to the candidate set of the disconnectable power transmission line, determining a first constraint condition as follows:
Figure BDA0002753767020000071
Figure BDA0002753767020000072
Figure BDA0002753767020000073
Pijmax(Oij-1)≤Pij≤Pijmax(1-Oij),(i,j)∈Lon∪Loff
Figure BDA0002753767020000074
Figure BDA0002753767020000081
Figure BDA0002753767020000082
wherein the content of the first and second substances,
Figure BDA0002753767020000083
and
Figure BDA0002753767020000084
respectively representing the upper limit and the lower limit of the reactive output of the generator; pGiRepresenting the active output of the generator set; pijRepresenting the active power flow of the transmission line ij; sNRepresenting a set of all generator nodes in the transmission grid; m is a sufficiently large positive number; x is the number ofijRepresenting an impedance parameter of the transmission line ij; thetaiRepresents the phase angle of node i; l represents the set of all transmission lines in the transmission network; j denotes the maximum number of line state adjustments.
Further, according to the candidate set of the disconnectable power transmission line, determining a second constraint condition as follows:
Figure BDA0002753767020000085
Figure BDA0002753767020000086
Figure BDA0002753767020000087
Figure BDA0002753767020000088
Figure BDA0002753767020000089
Figure BDA00027537670200000810
Figure BDA00027537670200000811
Figure BDA00027537670200000812
Figure BDA00027537670200000813
Figure BDA00027537670200000814
wherein the content of the first and second substances,
Figure BDA00027537670200000815
and
Figure BDA00027537670200000816
respectively representing the upper limit and the lower limit of the reactive output of the generator; n represents all node sets of the power transmission network; v. ofnRepresenting the voltage amplitude of node n in the transmission network;
Figure BDA0002753767020000091
and
Figure BDA0002753767020000092
respectively representing the upper limit and the lower limit of the voltage of the node n;
Figure BDA0002753767020000093
and
Figure BDA0002753767020000094
respectively representing the upper limit and the lower limit of the phase angle of the node n; qijRepresenting the reactive power flow of the transmission line ij; sijRepresenting the apparent power flow of the transmission line ij; qLiRepresenting the reactive power load size of the node; gijAnd bijRespectively representing the conductance and susceptance of the power transmission line ij; v. ofi、vjRespectively representing voltage amplitudes of nodes i and j at two ends of the power transmission line ij; qGiAnd the reactive output of the generator set after the network reconstruction is represented.
The invention has the following beneficial effects:
1. the optimal solution of the first mathematical model is used as the initial solution of the second mathematical model, the advantages of the two mathematical models are combined, the requirement of the second mathematical model on convergence reliability is lowered, the condition that the optimal solution obtained by only using a direct current method power flow equation is too different from the actual optimal solution is avoided, and the condition that the equation is not converged and cannot be solved easily by only using an alternating current method power flow equation is also avoided.
2. According to the invention, through the objective function, lines and equipment which need to be adjusted for network reconstruction are reduced as much as possible, so that negative effects on the operation of a power grid are reduced.
3. The invention sorts according to the absolute value of the distribution factor of the line disconnection, and can intuitively find the transmission line which has larger influence on the distribution of the tidal current in the transmission network. Furthermore, the lines are brought into the candidate set of the disconnectable lines, so that on one hand, the dimension for solving the equation set to be solved in the first mathematical model and the second output model can be greatly reduced, the dimension disaster is avoided, and the calculation efficiency is improved; on the other hand, the accuracy of the optimal solution can be improved.
Drawings
FIG. 1 is a flow chart of the present invention;
FIG. 2 is a flow chart for solving a first mathematical model by branch-and-bound;
FIG. 3 is a diagram of an actual power flow distribution before a fault occurs in a certain area;
FIG. 4 is a power flow distribution diagram after a fault occurs in the region;
FIG. 5 is a power flow distribution diagram for the region after using a common fault emergency handling method;
figure 6 is a power flow distribution diagram of the region after the scheme of the invention is used.
Detailed Description
The invention is described in detail below with reference to the figures and the specific embodiments.
Example one
Referring to fig. 1, a power transmission network line power flow out-of-limit solving method based on network reconstruction includes the following steps:
establishing a first mathematical model based on a direct current power flow equation, wherein the first mathematical model consists of an objective function and a first constraint condition; establishing a second mathematical model based on the alternating current power flow equation, wherein the second mathematical model consists of an objective function and a second constraint condition; the method comprises the following steps:
s1, establishing an objective function: constructing a target function with the aim of adjusting the minimum number of the transmission lines, the minimum active output cost of the set and the minimum load shedding cost; s2, establishing a first constraint condition and a second constraint condition: establishing a candidate set of disconnectable transmission lines consisting of hot standby transmission lines and operating transmission lines according to the line disconnection distribution factors; respectively determining a first constraint condition and a second constraint condition according to the candidate set of the disconnectable power transmission line;
and solving the first mathematical model by a branch-and-bound method to obtain the optimal solution of the first mathematical model. And taking the optimal solution as an initial solution of the second mathematical model, and solving the second mathematical model by a primal-dual interior point method to obtain the optimal solution of the second mathematical model, wherein the optimal solution of the second mathematical model is used for solving the problem of power flow out-of-limit and comprises a plurality of power transmission lines needing to be disconnected.
The beneficial effect of this implementation lies in: the optimal solution of the first mathematical model is used as the initial solution of the second mathematical model, the advantages of the two mathematical models are combined, the requirement of the second mathematical model on convergence reliability is lowered, the condition that the difference between the optimal solution obtained by only using a direct current method power flow equation and the actual optimal solution is too large is avoided, and the condition that the equation is not converged and cannot be solved easily by only using an alternating current method power flow equation is also avoided.
Example two
Further, the objective function is:
Figure BDA0002753767020000111
wherein i and j represent nodes at two ends of the transmission line ij respectively; o isijRepresenting the operating state of the transmission line ij: o isijWhen 0 denotes transmission line operation, OijWhen the value is 1, the power transmission line is interrupted; l isonRepresenting all hot standby transmission lines in the disconnectable transmission line candidate set; l isoffRepresenting all the operating transmission lines in the disconnectable transmission line candidate set; sGRepresenting a generator node set; sLRepresenting a set of all load nodes in the power transmission network; wGiExpressing the weight of unit output of the adjusting unit;
Figure BDA0002753767020000112
representing the active output of the generator set in an initial state; pGiRepresenting the active output of the generator set after iterative computation updating; wLiA weight representing an adjustment unit load amount; rLiRepresenting the load shedding rate of a node i in the power transmission network; pLiIndicating the magnitude of the load.
The improvement of the embodiment is that the objective function aims at adjusting the minimum number of the transmission lines, the minimum active output cost of the set and the minimum load shedding cost, and reduces lines and equipment required to be adjusted for network reconstruction as much as possible, so that the negative influence on the operation of the power grid is reduced.
EXAMPLE III
Further, according to the line disconnection distribution factor, the step of establishing the disconnectable power transmission line candidate set is as follows:
establishing a candidate set of the disconnectable power transmission line with an initial state as an empty set;
and for the hot standby power transmission line, if a certain line is put into operation to reduce the tidal current overload, adding the line into the candidate set of the disconnectable power transmission line.
And for the power transmission line in operation, if one line is disconnected to reduce the power flow overload, adding the line into the candidate set of the disconnectable power transmission line.
And respectively calculating the line disconnection distribution factor of each line in the disconnectable power transmission line candidate set (when the line fails, the power flow transfer in the power transmission network is caused, so that corresponding power flow change is generated on the rest of all lines, and therefore the line disconnection distribution factor of the rest of all lines to the line l needs to be calculated).
Taking line l as an example: and respectively calculating the line disconnection distribution factors of the remaining lines to the line l according to the following formula.
ΔPk,l＝Dk,lPl 0,(k,l)∈L
Figure BDA0002753767020000121
Figure BDA0002753767020000122
Figure BDA0002753767020000123
Wherein, Δ Pk,lRepresenting the power flow variation of the line k; dk,lRepresenting a line break distribution factor of a line k to a line l; pl 0Representing the initial power flow of the line l；Xk,lRepresenting the transimpedance between the pair of port k and port l nodes; xl,lRepresents the self-impedance of line l; x represents an impedance matrix in the nodal power grid; mlAnd MkNode-line association vectors representing lines k and l, respectively; x is the number ofkAnd xlRepresenting the reactance of lines k and l, respectively.
Sorting the lines in the candidate set of the disconnectable power transmission lines according to the absolute values of the line disconnection distribution factors to obtain the ranking of each line; lines ranked below a threshold are deleted. In the present embodiment, the threshold is set to 50% of the total number of lines in the candidate set. For example, 100 lines are collected in the disconnected power transmission line candidate set, and after sorting, the lines with the rank lower than 50 are deleted.
Further, the specific steps of establishing the first constraint condition according to the candidate set of the disconnectable power transmission line are as follows:
Figure BDA0002753767020000131
Figure BDA0002753767020000132
Figure BDA0002753767020000133
Pijmax(Oij-1)≤Pij≤Pijmax(1-Oij),(i,j)∈Lon∪Loff
Figure BDA0002753767020000134
Figure BDA0002753767020000135
Figure BDA0002753767020000136
wherein the content of the first and second substances,
Figure BDA0002753767020000137
and
Figure BDA0002753767020000138
respectively representing the upper limit and the lower limit of the reactive output of the generator; pGiRepresenting the active output of the generator set; pijRepresenting the active power flow of the transmission line ij; sNRepresenting a set of all generator nodes in the transmission grid; m is a sufficiently large positive number; x is the number ofijRepresenting an impedance parameter of the transmission line ij; thetaiRepresents the phase angle of node i; l represents the set of all transmission lines in the transmission network; j denotes the maximum number of line state adjustments.
Further, the specific steps of establishing a second constraint condition according to the candidate set of the disconnectable power transmission line are as follows:
Figure BDA0002753767020000141
Figure BDA0002753767020000142
Figure BDA0002753767020000143
Figure BDA0002753767020000144
Figure BDA0002753767020000145
Figure BDA0002753767020000146
Figure BDA0002753767020000147
Figure BDA0002753767020000148
Figure BDA0002753767020000149
Figure BDA00027537670200001410
wherein the content of the first and second substances,
Figure BDA00027537670200001411
and
Figure BDA00027537670200001412
respectively representing the upper limit and the lower limit of the reactive output of the generator; n represents all node sets of the power transmission network; v. ofnRepresenting the voltage amplitude of node n in the transmission network;
Figure BDA00027537670200001413
and
Figure BDA00027537670200001414
respectively representing the upper limit and the lower limit of the voltage of the node n;
Figure BDA00027537670200001415
and
Figure BDA00027537670200001416
respectively representing the upper limit and the lower limit of the phase angle of the node n; qijRepresenting the reactive power flow of the transmission line ij; sijRepresenting the apparent power flow of the transmission line ij; qLiReactive power load representing a nodeSize; gijAnd bijRespectively representing the conductance and susceptance of the power transmission line ij; v. ofi、vjRespectively representing voltage amplitudes of nodes i and j at two ends of the power transmission line ij; qGiAnd the reactive output of the generator set after the network reconstruction is represented.
The improvement of the embodiment is that the transmission lines with large influence on the moisture distribution in the transmission network can be intuitively found according to the sorting of the absolute values of the line breaking distribution factors. Furthermore, the lines are brought into the candidate set of the disconnectable lines, so that on one hand, the dimension for solving the equation set to be solved in the first mathematical model and the second output model can be greatly reduced, the dimension disaster is avoided, and the calculation efficiency is improved; on the other hand, only the line with larger influence is considered, the range of feasible domains of the solution is reduced, and the accuracy of the optimal solution is improved.
Example four
Specific information of the branch-and-bound method and the primal-dual interior point method can be referred to documents 'application of the primal-dual interior point method and the bound method in reactive power optimization', 'linear mixed integer programming problem optimization algorithm and application thereof in a power system' and 'reactive power optimization mixed algorithm based on the improved genetic algorithm and the primal-dual interior point method'.
Referring to FIG. 2, the steps for solving the first mathematical model by branch-and-bound method are as follows:
(1) and (5) initializing. Upper bound of objective function value
Figure BDA0002753767020000151
Is a sufficiently large number. Relax the original problem (i.e. transform the original problem into a corresponding relaxed linear programming problem). And substituting the candidate set of the disconnectable circuit into the relaxed linear programming problem, and solving the solution of the relaxed linear programming problem by an interior point method.
(2) And (5) if no feasible solution exists, jumping to the step (8).
(3) If the objective function value of the current solution exceeds
Figure BDA0002753767020000152
And (5) jumping to the step (8).
(4) And (7) if the current solution is an integer, jumping to the step (7).
(5) And performing predictive selection of branch variables based on sensitivity analysis, performing branching according to the selected variables, and recording branch information. Where branching refers to splitting the feasible solution space into multiple small subspaces.
(6) And (3) selecting one branch, solving by an interior point method, and then jumping to the step (2).
(7) Updating the optimal solution sum according to the obtained current solution
Figure BDA0002753767020000153
(8) Judging whether branches which are not searched exist, if all the branches are searched, stopping calculation, and obtaining the optimal solution, namely the optimal solution of the original problem; otherwise, backtracking to the latest branch which is not searched along the branch, solving by using an interior point method, and then jumping to the step (2).
The optimal solution of the first mathematical model, namely a plurality of power transmission lines needing to be disconnected, is obtained through the steps. However, the difference between the obtained solution and the actual optimal solution is large, and the problem of power flow out-of-limit cannot be solved well. Therefore, further optimization of the optimal solution of the first mathematical model is required.
Solving the second mathematical model by a primal-dual interior point method to optimize the optimal solution of the first mathematical model, and the steps are as follows:
(1) and introducing a relaxation variable to condition the inequality constraint in the second constraint condition into an equality constraint condition and a variable inequality constraint condition.
(2) Processing the equivalent constraint condition by using a Lagrange multiplier method; and processing the variable inequality constraint conditions by using an interior point barrier function method and a constraint step method.
(3) Defining a Lagrangian function; and (4) deriving a Cohn-Cuck optimality condition according to the Lagrange function, and further forming a Newton-Raphson iteration equation.
(4) And substituting the optimal solution obtained by the first mathematical model as an initial solution into a Newton-Raphson iteration equation to carry out iterative computation. In the iterative calculation process, an initial barrier factor which is large enough to ensure the feasibility of the solution is taken, and then the barrier factor is gradually reduced to ensure the optimality of the solution. And finally obtaining the optimal solution of the second mathematical model until the error reaches an acceptable range.
The optimal solution of the second mathematical model obtained at the moment can well solve the problem of power flow out-of-limit.
EXAMPLE five
Referring to fig. 3 to 6, taking the power transmission network of a certain area as an example:
fig. 3 to 6 include a plurality of transmission lines and a plurality of busbars. For the bus, the thicker bus represents 500kv, the thinner bus represents 220 kv; for the transmission line, a solid line indicates that the transmission line in the running state runs in a double-line mode, and a dotted line indicates that the transmission line in the running state runs in a single-line mode; the dotted line represents the transmission line in the disconnected state; the bold solid line indicates that a tidal current violation has occurred in the line.
The area grid is in normal operation in fig. 3.
In FIG. 4, a power flow violation occurs in line LT-JJ due to the sudden disconnection of the SB-XS line.
Fig. 5 is a power flow distribution diagram of the region after the normal fault emergency treatment method is used, and the total required load shedding amount of XT, ML and SB of the region is 395.8MW (power supply reduction).
Fig. 6 is a power flow distribution diagram of the region after the scheme of the invention is used, and power flow out-of-limit is eliminated BY adjusting the output of the unit and closing the QM-ML and BY-LT two-wire loop.
Obviously, the invention avoids load shedding and ensures the reliability of power supply of a power grid and the normal power consumption of residents by adjusting the power equipment and the power transmission line.
EXAMPLE six
A grid line power flow violation solving device based on network reconfiguration, comprising a memory and a processor, the memory storing instructions adapted to be loaded by the processor and to perform the steps of:
establishing a first mathematical model based on a direct current power flow equation, wherein the first mathematical model consists of an objective function and a first constraint condition; establishing a second mathematical model based on the alternating current power flow equation, wherein the second mathematical model consists of an objective function and a second constraint condition; the method comprises the following steps:
s1, establishing an objective function: constructing a target function with the aim of adjusting the minimum number of the transmission lines, the minimum active output cost of the set and the minimum load shedding cost; s2, establishing a first constraint condition and a second constraint condition: establishing a candidate set of disconnectable transmission lines consisting of hot standby transmission lines and operating transmission lines according to the line disconnection distribution factors; respectively determining a first constraint condition and a second constraint condition according to the candidate set of the disconnectable power transmission line;
and solving the first mathematical model by a branch-and-bound method to obtain the optimal solution of the first mathematical model. And taking the optimal solution as an initial solution of the second mathematical model, and solving the second mathematical model by a primal-dual interior point method to obtain the optimal solution of the second mathematical model, wherein the optimal solution of the second mathematical model is used for solving the problem of power flow out-of-limit and comprises a plurality of power transmission lines needing to be disconnected.
The beneficial effect of this implementation lies in: the optimal solution of the first mathematical model is used as the initial solution of the second mathematical model, the advantages of the two mathematical models are combined, the requirement of the second mathematical model on convergence reliability is lowered, the condition that the difference between the optimal solution obtained by only using a direct current method power flow equation and the actual optimal solution is too large is avoided, and the condition that the equation is not converged and cannot be solved easily by only using an alternating current method power flow equation is also avoided.
EXAMPLE seven
Further, the objective function is:
Figure BDA0002753767020000181
wherein i and j represent nodes at two ends of the transmission line ij respectively; o isijRepresenting the operating state of the transmission line ij: o isijWhen 0 denotes transmission line operation, OijWhen the value is 1, the power transmission line is interrupted; l isonRepresenting all hot standby transmission lines in the disconnectable transmission line candidate set; l isoffRepresenting all the operating transmission lines in the disconnectable transmission line candidate set; sGRepresenting a generator node set; sLRepresenting a set of all load nodes in the power transmission network; wGiExpressing the weight of unit output of the adjusting unit;
Figure BDA0002753767020000182
representing the active output of the generator set in an initial state; pGiRepresenting the active output of the generator set after iterative computation updating; wLiA weight representing an adjustment unit load amount; rLiRepresenting the load shedding rate of a node i in the power transmission network; pLiIndicating the magnitude of the load.
The improvement of the embodiment is that the objective function aims at adjusting the minimum number of the transmission lines, the minimum active output cost of the set and the minimum load shedding cost, and reduces lines and equipment required to be adjusted for network reconstruction as much as possible, so that the negative influence on the operation of the power grid is reduced.
Example eight
Further, according to the line disconnection distribution factor, the step of establishing the disconnectable power transmission line candidate set is as follows:
establishing a candidate set of the disconnectable power transmission line with an initial state as an empty set;
and for the hot standby power transmission line, if a certain line is put into operation to reduce the tidal current overload, adding the line into the candidate set of the disconnectable power transmission line.
And for the power transmission line in operation, if one line is disconnected to reduce the power flow overload, adding the line into the candidate set of the disconnectable power transmission line.
And respectively calculating the line disconnection distribution factor of each line in the disconnectable power transmission line candidate set (when the line fails, the power flow transfer in the power transmission network is caused, so that corresponding power flow change is generated on the rest of all lines, and therefore the line disconnection distribution factor of the rest of all lines to the line l needs to be calculated).
Taking line l as an example: and respectively calculating the line disconnection distribution factors of the remaining lines to the line l according to the following formula.
ΔPk,l＝Dk,lPl 0,(k,l)∈L
Figure BDA0002753767020000191
Figure BDA0002753767020000201
Figure BDA0002753767020000202
Wherein, Δ Pk,lRepresenting the power flow variation of the line k; dk,lRepresenting a line break distribution factor of a line k to a line l; pl 0Represents the initial power flow of the line l; xk,lRepresenting the transimpedance between the pair of port k and port l nodes; xl,lRepresents the self-impedance of line l; x represents an impedance matrix in the nodal power grid; mlAnd MkNode-line association vectors representing lines k and l, respectively; x is the number ofkAnd xlRepresenting the reactance of lines k and l, respectively.
Sorting the lines in the candidate set of the disconnectable power transmission lines according to the absolute values of the line disconnection distribution factors to obtain the ranking of each line; lines ranked below a threshold are deleted. In the present embodiment, the threshold is set to 50% of the total number of lines in the candidate set. For example, 100 lines are collected in the disconnected power transmission line candidate set, and after sorting, the lines with the rank lower than 50 are deleted.
Further, the specific steps of establishing the first constraint condition according to the candidate set of the disconnectable power transmission line are as follows:
Figure BDA0002753767020000203
Figure BDA0002753767020000204
Figure BDA0002753767020000205
Pijmax(Oij-1)≤Pij≤Pijmax(1-Oij),(i,j)∈Lon∪Loff
Figure BDA0002753767020000206
Figure BDA0002753767020000207
Figure BDA0002753767020000208
wherein the content of the first and second substances,
Figure BDA00027537670200002117
and
Figure BDA00027537670200002118
respectively representing the upper limit and the lower limit of the reactive output of the generator; pGiRepresenting the active output of the generator set; pijRepresenting the active power flow of the transmission line ij; sNRepresenting a set of all generator nodes in the transmission grid; m is a sufficiently large positive number; x is the number ofijRepresenting an impedance parameter of the transmission line ij; thetaiRepresents the phase angle of node i; l represents the set of all transmission lines in the transmission network; j denotes the maximum number of line state adjustments.
Further, the specific steps of establishing a second constraint condition according to the candidate set of the disconnectable power transmission line are as follows:
Figure BDA0002753767020000211
Figure BDA0002753767020000212
Figure BDA0002753767020000213
Figure BDA0002753767020000214
Figure BDA0002753767020000215
Figure BDA0002753767020000216
Figure BDA0002753767020000217
Figure BDA0002753767020000218
Figure BDA0002753767020000219
Figure BDA00027537670200002110
wherein the content of the first and second substances,
Figure BDA00027537670200002111
and
Figure BDA00027537670200002112
respectively representing the upper limit and the lower limit of the reactive output of the generator; n represents all node sets of the power transmission network; v. ofnRepresenting the voltage amplitude of node n in the transmission network;
Figure BDA00027537670200002113
and
Figure BDA00027537670200002114
respectively representing the upper limit and the lower limit of the voltage of the node n;
Figure BDA00027537670200002115
and
Figure BDA00027537670200002116
respectively representing the upper limit and the lower limit of the phase angle of the node n; qijRepresenting the reactive power flow of the transmission line ij; sijRepresenting the apparent power flow of the transmission line ij; qLiRepresenting the reactive power load size of the node; gijAnd bijRespectively representing the conductance and susceptance of the power transmission line ij; v. ofi、vjRespectively representing voltage amplitudes of nodes i and j at two ends of the power transmission line ij; qGiAnd the reactive output of the generator set after the network reconstruction is represented.
The improvement of the embodiment is that the transmission lines with large influence on the moisture distribution in the transmission network can be intuitively found according to the sorting of the absolute values of the line breaking distribution factors. Furthermore, the lines are brought into the candidate set of the disconnectable lines, so that on one hand, the dimension for solving the equation set to be solved in the first mathematical model and the second output model can be greatly reduced, the dimension disaster is avoided, and the calculation efficiency is improved; on the other hand, only the line with larger influence is considered, the range of feasible domains of the solution is reduced, and the accuracy of the optimal solution is improved.
Example nine
Specific information of the branch-and-bound method and the primal-dual interior point method can be referred to documents 'application of the primal-dual interior point method and the bound method in reactive power optimization', 'linear mixed integer programming problem optimization algorithm and application thereof in a power system' and 'reactive power optimization mixed algorithm based on the improved genetic algorithm and the primal-dual interior point method'.
Referring to FIG. 2, the steps for solving the first mathematical model by branch-and-bound method are as follows:
(1) and (5) initializing. Upper bound of objective function value
Figure BDA0002753767020000221
Is a sufficiently large number. Relax the original problem (i.e. transform the original problem into a corresponding relaxed linear programming problem). And substituting the candidate set of the disconnectable circuit into the relaxed linear programming problem, and solving the solution of the relaxed linear programming problem by an interior point method.
(2) And (5) if no feasible solution exists, jumping to the step (8).
(3) If the objective function value of the current solution exceeds
Figure BDA0002753767020000222
And (5) jumping to the step (8).
(4) And (7) if the current solution is an integer, jumping to the step (7).
(5) And performing predictive selection of branch variables based on sensitivity analysis, performing branching according to the selected variables, and recording branch information. Where branching refers to splitting the feasible solution space into multiple small subspaces.
(6) And (3) selecting one branch, solving by an interior point method, and then jumping to the step (2).
(7) Updating the optimal solution sum according to the obtained current solution
Figure BDA0002753767020000231
(8) Judging whether branches which are not searched exist, if all the branches are searched, stopping calculation, and obtaining the optimal solution, namely the optimal solution of the original problem; otherwise, backtracking to the latest branch which is not searched along the branch, solving by using an interior point method, and then jumping to the step (2).
The optimal solution of the first mathematical model, namely a plurality of power transmission lines needing to be disconnected, is obtained through the steps. However, the difference between the obtained solution and the actual optimal solution is large, and the problem of power flow out-of-limit cannot be solved well. Therefore, further optimization of the optimal solution of the first mathematical model is required.
Solving the second mathematical model by a primal-dual interior point method to optimize the optimal solution of the first mathematical model, and the steps are as follows:
(1) and introducing a relaxation variable to condition the inequality constraint in the second constraint condition into an equality constraint condition and a variable inequality constraint condition.
(2) Processing the equivalent constraint condition by using a Lagrange multiplier method; and processing the variable inequality constraint conditions by using an interior point barrier function method and a constraint step method.
(3) Defining a Lagrangian function; and (4) deriving a Cohn-Cuck optimality condition according to the Lagrange function, and further forming a Newton-Raphson iteration equation.
(4) And substituting the optimal solution obtained by the first mathematical model as an initial solution into a Newton-Raphson iteration equation to carry out iterative computation. In the iterative calculation process, an initial barrier factor which is large enough to ensure the feasibility of the solution is taken, and then the barrier factor is gradually reduced to ensure the optimality of the solution. And finally obtaining the optimal solution of the second mathematical model until the error reaches an acceptable range.
The optimal solution of the second mathematical model obtained at the moment can well solve the problem of power flow out-of-limit.
Example ten
Referring to fig. 3 to 6, taking the power transmission network of a certain area as an example:
fig. 3 to 6 include a plurality of transmission lines and a plurality of busbars. For the bus, the thicker bus represents 500kv, the thinner bus represents 220 kv; for the transmission line, a solid line indicates that the transmission line in the running state runs in a double-line mode, and a dotted line indicates that the transmission line in the running state runs in a single-line mode; the dotted line represents the transmission line in the disconnected state; the bold solid line indicates that a tidal current violation has occurred in the line.
The area grid is in normal operation in fig. 3.
In FIG. 4, a power flow violation occurs in line LT-JJ due to the sudden disconnection of the SB-XS line.
Fig. 5 is a power flow distribution diagram of the region after the normal fault emergency treatment method is used, and the total required load shedding amount of XT, ML and SB of the region is 395.8MW (power supply reduction).
Fig. 6 is a power flow distribution diagram of the region after the scheme of the invention is used, and power flow out-of-limit is eliminated BY adjusting the output of the unit and closing the QM-ML and BY-LT two-wire loop.
Obviously, the invention avoids load shedding and ensures the reliability of power supply of a power grid and the normal power consumption of residents by adjusting the power equipment and the power transmission line.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (6)

1. A power transmission network line power flow out-of-limit solving method based on network reconstruction is characterized by comprising the following steps:
establishing a first mathematical model based on a direct current power flow equation, wherein the first mathematical model consists of an objective function and a first constraint condition; establishing a second mathematical model based on the alternating current power flow equation, wherein the second mathematical model consists of an objective function and a second constraint condition; the method comprises the following steps:
s1, establishing an objective function: constructing a target function with the aim of adjusting the minimum number of the transmission lines, the minimum active output cost of the set and the minimum load shedding cost; s2, establishing a first constraint condition and a second constraint condition: establishing a candidate set of disconnectable transmission lines consisting of hot standby transmission lines and operating transmission lines according to the line disconnection distribution factors; respectively determining a first constraint condition and a second constraint condition according to the candidate set of the disconnectable power transmission line;
solving the first mathematical model by a branch-and-bound method to obtain an optimal solution of the first mathematical model; and taking the optimal solution as an initial solution of the second mathematical model, and solving the second mathematical model by a primal-dual interior point method to obtain the optimal solution of the second mathematical model, wherein the optimal solution of the second mathematical model is used for solving the problem of power flow out-of-limit and comprises a plurality of power transmission lines needing to be disconnected.
2. The method for solving the out-of-limit power flow of the power transmission network based on the network reconstruction as claimed in claim 1, wherein the objective function is as follows:
Figure FDA0002753767010000011
wherein i and j represent nodes at two ends of the transmission line ij respectively; o isijRepresenting the operating state of the transmission line ij: o isijWhen 0 denotes transmission line operation, OijWhen the value is 1, the power transmission line is interrupted; l isonRepresenting all hot standby transmission lines in the disconnectable transmission line candidate set; l isoffRepresenting all the operating transmission lines in the disconnectable transmission line candidate set; sGRepresenting a generator node set; sLRepresenting a set of all load nodes in the power transmission network; wGiExpressing the weight of unit output of the adjusting unit;
Figure FDA0002753767010000021
representing the active output of the generator set in an initial state; pGiRepresenting the active output of the generator set after iterative computation updating; wLiA weight representing an adjustment unit load amount; rLiRepresenting the load shedding rate of a node i in the power transmission network; pLiIndicating the magnitude of the load.
3. The method for solving the power transmission network line power flow out-of-limit based on the network reconstruction as claimed in claim 2, wherein the step of establishing the candidate set of the disconnectable power transmission line according to the line disconnection distribution factor comprises the following steps:
establishing a candidate set of the disconnectable power transmission line with an initial state as an empty set;
for hot standby transmission lines, if a certain hot standby transmission line can reduce tidal current overload when put into operation, adding the line into the candidate set of the disconnectable transmission lines;
for the power transmission lines in operation, if the power transmission line in operation is disconnected and the tidal current overload can be reduced, adding the line into the candidate set of the power transmission lines which can be disconnected;
respectively calculating the line breaking distribution factor of each line in the candidate set of the breakable power transmission lines;
sorting the lines in the candidate set of the disconnectable power transmission lines according to the absolute values of the line disconnection distribution factors to obtain the ranking of each line; lines ranked below a threshold are deleted.
4. The method for solving the out-of-limit power transmission network line power flow based on network reconstruction as claimed in claim 3, wherein according to the candidate set of breakable power transmission lines, the first constraint condition is determined as follows:
Figure FDA0002753767010000022
Figure FDA0002753767010000023
Figure FDA0002753767010000031
Pijmax(Oij-1)≤Pij≤Pijmax(1-Oij),(i,j)∈Lon∪Loff
Figure FDA0002753767010000032
Figure FDA0002753767010000033
Figure FDA0002753767010000034
wherein the content of the first and second substances,
Figure FDA0002753767010000035
and
Figure FDA0002753767010000036
respectively representing the upper limit and the lower limit of the reactive output of the generator; pGiRepresenting the active output of the generator set; pijRepresenting the active power flow of the transmission line ij; sNRepresenting a set of all generator nodes in the transmission grid; m is a sufficiently large positive number; x is the number ofijRepresenting an impedance parameter of the transmission line ij; thetaiRepresents the phase angle of node i; l represents the set of all transmission lines in the transmission network; j denotes the maximum number of line state adjustments.
5. The method for solving the out-of-limit power transmission network line power flow based on network reconstruction as claimed in claim 4, wherein according to the candidate set of breakable power transmission lines, the second constraint condition is determined as follows:
Figure FDA0002753767010000037
Figure FDA0002753767010000038
Figure FDA0002753767010000039
Figure FDA00027537670100000310
Figure FDA00027537670100000311
Figure FDA00027537670100000312
Figure FDA0002753767010000041
Figure FDA0002753767010000042
Figure FDA0002753767010000043
Figure FDA0002753767010000044
wherein the content of the first and second substances,
Figure FDA0002753767010000045
and
Figure FDA0002753767010000046
respectively representing the upper limit and the lower limit of the reactive output of the generator; n represents all node sets of the power transmission network; v. ofnRepresenting the voltage amplitude of node n in the transmission network;
Figure FDA0002753767010000047
and
Figure FDA0002753767010000048
respectively representing the upper limit and the lower limit of the voltage of the node n;
Figure FDA0002753767010000049
and
Figure FDA00027537670100000410
respectively representing the upper limit and the lower limit of the phase angle of the node n; qijRepresenting the reactive power flow of the transmission line ij; sijRepresenting the apparent power flow of the transmission line ij; qLiRepresenting the reactive power load size of the node; gijAnd bijRespectively representing the conductance and susceptance of the power transmission line ij; v. ofi、vjRespectively representing voltage amplitudes of nodes i and j at two ends of the power transmission line ij; qGiAnd the reactive output of the generator set after the network reconstruction is represented.
6. A network reconfiguration based power transmission network line power flow violation solving device comprising a memory and a processor, wherein the memory stores instructions adapted to be loaded and executed by the processor to perform a network reconfiguration based power transmission network line power flow violation solving method according to any of claims 1-5.
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