CN112909942A - Active power distribution network fault recovery method and system based on hybrid solution strategy - Google Patents

Active power distribution network fault recovery method and system based on hybrid solution strategy Download PDF

Info

Publication number
CN112909942A
CN112909942A CN202110436401.1A CN202110436401A CN112909942A CN 112909942 A CN112909942 A CN 112909942A CN 202110436401 A CN202110436401 A CN 202110436401A CN 112909942 A CN112909942 A CN 112909942A
Authority
CN
China
Prior art keywords
distribution network
power distribution
active power
fault recovery
load
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202110436401.1A
Other languages
Chinese (zh)
Other versions
CN112909942B (en
Inventor
张庆平
黄鸣宇
张沈习
闫振华
高博
夏绪卫
李秀广
李学锋
周秀
亓亮
马瑞
朱东歌
罗海荣
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shanghai Jiaotong University
Electric Power Research Institute of State Grid Ningxia Electric Power Co Ltd
Original Assignee
Shanghai Jiaotong University
Electric Power Research Institute of State Grid Ningxia Electric Power Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shanghai Jiaotong University, Electric Power Research Institute of State Grid Ningxia Electric Power Co Ltd filed Critical Shanghai Jiaotong University
Priority to CN202110436401.1A priority Critical patent/CN112909942B/en
Publication of CN112909942A publication Critical patent/CN112909942A/en
Application granted granted Critical
Publication of CN112909942B publication Critical patent/CN112909942B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • H02J3/007—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources
    • H02J3/0073—Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources for providing alternative feeding paths between load and source when the main path fails, e.g. transformers, busbars
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H02H7/28—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for meshed systems
    • 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
    • H02J3/388—Islanding, i.e. disconnection of local power supply from the network
    • 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
    • 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]

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

The invention relates to a method and a system for recovering active power distribution network faults based on a hybrid solution strategy, wherein the method comprises the following steps: step S1, constructing an active power distribution network island division and network reconstruction unified model containing a distributed power supply and energy storage, wherein an objective function of the model considers equivalent power loss load, section switch operation and network loss cost; step S2, solving the unified model by adopting a hybrid solving strategy based on the combination of breadth-first search, depth-first search and second-order cone optimization to obtain a line maintenance scheme; and step S3, realizing the fault recovery of the active power distribution network based on the line maintenance scheme. Compared with the prior art, the method has the advantages of improving the fault recovery rate, being high in solving speed of the maintenance scheme and the like.

Description

Active power distribution network fault recovery method and system based on hybrid solution strategy
Technical Field
The invention relates to an active power distribution network fault recovery technology, in particular to an active power distribution network fault recovery method and system based on a hybrid solution strategy.
Background
The faults of the power distribution network directly affect the production of the society and the daily power supply of residents. In response to sudden natural disasters, compared with the protection of a power distribution network, a power grid side starts to seek a method for rapidly recovering a power distribution system by using a black-start distributed power supply after the disasters occur so as to improve the reliability. An active distribution network (AND) has a Distributed Generation (DG) which can be used as a black start power supply as a backup, AND the characteristic of flexible AND changeable network topology also provides more optimization possibilities for an active distribution network fault recovery strategy. Therefore, a fault recovery strategy for power distribution network topology transformation becomes one of the research hotspots in the field of distribution networks.
After a fault occurs in the active power distribution network, an isolated island operation is generally formed by reasonably and effectively dividing a distributed power supply independently, or the remaining power loss area is connected with a main network by a method of changing a network topological structure independently through network reconstruction to recover power supply. Compared with the traditional power distribution network, the active power distribution network containing the DGs has more factors to be considered for fault recovery, the load and the intermittency and fluctuation of the DG output bring more influence factors to the original fault recovery method, and the problem of insufficient fault recovery rate exists in the conventional fault recovery method.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide the active power distribution network fault recovery method and system based on the hybrid solving strategy, which can improve the fault recovery rate and increase the solving speed of the maintenance scheme.
The purpose of the invention can be realized by the following technical scheme:
a hybrid solution strategy-based active power distribution network fault recovery method comprises the following steps:
step S1, constructing an active power distribution network island division and network reconstruction unified model containing a distributed power supply and energy storage, wherein an objective function of the model considers equivalent power loss load, section switch operation and network loss cost;
step S2, solving the unified model by adopting a hybrid solving strategy based on the combination of breadth-first search, depth-first search and second-order cone optimization to obtain a line maintenance scheme;
and step S3, realizing the fault recovery of the active power distribution network based on the line maintenance scheme.
Further, the objective function is represented as:
Figure BDA0003033320730000021
in the formula: g1,tNetwork loss in a system t period; g2,tThe operation times of the switch are segmented for the t time period of the system; g3,tThe equivalent load recovery quantity of the system in the time period t is obtained; lambda [ alpha ]iIs the load weight of node i; pi,tThe active power of the load node i in the load t period is obtained;
Figure BDA0003033320730000025
representing a set of load nodes; upsilon is1、υ2、υ3Respectively a network loss cost coefficient, a switch operation cost coefficient and an equivalent power loss load cost coefficient, NTFor the number of time periods that the entire fault recovery lasts, Δ t is the duration of a single time period.
Further, the network loss calculation method comprises the following steps:
Figure BDA0003033320730000022
in the formula: i isij,tIs the effective value R of the i-j current of the branch circuit in the t period of the systemijIs the resistance value of branch i-j; omega is a set of all branches of the active power distribution network;
the method for calculating the operation times of the section switch comprises the following steps:
Figure BDA0003033320730000023
in the formula: decision variable alphaij,tFor the switch state of the line i-j in the period t, taking 0 to represent that the line i-j switch is disconnected, and taking 1 to represent that the line i-j switch is closed;
the method for calculating the equivalent load recovery quantity comprises the following steps:
Figure BDA0003033320730000024
in the formula: decision variable yi,tFor the load recovery state of the node i in the period t, takeA1 indicates that the load i has recovered during the time period t, and a 0 indicates that the load i has not recovered during the time period t.
Furthermore, the constraint conditions of the active power distribution network island division and network reconstruction unified model comprise node voltage and branch current constraint, node power balance constraint, DG power constraint, network structure constraint, energy storage charging and discharging state and power constraint, energy storage residual capacity constraint, capacitor switching constraint and fault maintenance strategy constraint.
Further, in step S2, solving the unified model specifically includes:
step S201: reading the planned power failure time T of the fault, the DG output power in the period, the load prediction power and the energy storage charge state;
step S202: traversing each DG and the energy storage access node as root nodes, and determining a power circle by adopting a breadth-first search algorithm to obtain an island feasible solution;
step S203: obtaining an initial island division range by adopting a depth-first search algorithm according to the island feasible solution, and correcting the initial island division range according to an island fusion strategy to obtain an island division result in the time period;
step S204: obtaining a unified model of island division and network reconstruction of the active power distribution network in the time period based on the island division result in the time period, the position of the operable interconnection switch and the network topology structure;
step S205: constructing an intermediate variable, and carrying out linearization treatment on the unified model to convert the unified model into a standard mixed integer second-order cone model;
step S206: solving the standard mixed integer second order cone model by adopting a commercial solver;
step S207: and judging whether the calculation of all time intervals is finished, if so, outputting a final line maintenance scheme, otherwise, returning to the step S201 to calculate the next time interval.
Further, the correcting the initial island division range according to the island fusion strategy specifically includes:
and judging whether each island in the initial island division range has intersection, if so, fusing the islands with the intersection, recording the equivalent DG and equivalent nodes directly connected with the equivalent DG, returning to the step S202, if not, judging whether the adjacent islands meet the fusion constraint condition, if so, fusing, otherwise, canceling the fusion, and executing the step S204.
Further, the business solver comprises a YALMIP tool kit.
In step S205, convex relaxation is performed on the unified model by using a second-order cone relaxation technique, and the unified model is converted into the standard mixed integer second-order cone model.
Further, the feasible domain of the standard mixed integer second-order cone model is relaxed into the whole second-order cone, and the search space is in the convex cone range.
The invention also provides an active power distribution network fault recovery system based on the hybrid solution strategy, which comprises the following steps:
one or more processors, memory, and one or more programs stored in the memory, the one or more programs including instructions for performing the hybrid solution strategy-based proactive power distribution network fault recovery method described above.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the method, the active power distribution network fault recovery unified model considering the matching of island division and network reconstruction is established, the corresponding mixed solving strategy is proposed, all influence factors can be comprehensively considered, the fault recovery of the non-fault power failure area is jointly completed, and the reliability of the maintenance scheme is improved.
2. The objective function of the invention considers equivalent power loss load, section switch operation and network loss cost, and can comprehensively consider and integrate power loss amount during fault, economy corresponding to section switch operation and energy efficiency corresponding to network loss.
3. According to the method, a hybrid solving strategy based on the combination of breadth-first search, depth-first search and second-order cone optimization is adopted for solving, so that accurate and efficient solving of the active power distribution network fault planning model can be realized, and the model solving efficiency is improved.
4. According to the invention, the capacitor switching constraint condition is integrated, so that the fault recovery model can give consideration to both active power and reactive power, and the fault recovery rate is improved.
5. According to the invention, the fault maintenance strategy constraint conditions are integrated, and the fault repair sequence is optimized by adjusting the switch decision variables of the fault line, so that the optimal fault maintenance sequence is determined, and the power supply recovery rate is improved.
Drawings
FIG. 1 illustrates steps of a method for recovering a fault of an active power distribution network according to the present invention;
FIG. 2 is a flow chart of a solution of a unified model of islanding and network reconstruction;
FIG. 3 is an IEEE 33 node active power distribution network with DGs and energy storage;
FIG. 4 shows the result of fault recovery for islanding and network reconfiguration (14:00-15: 00);
FIG. 5 shows the result of fault recovery for islanding and network reconfiguration (15:00-16: 00);
FIG. 6 shows the result of fault recovery for islanding and network reconstruction (16:00-17: 00);
FIG. 7 shows the result of fault recovery for islanding and network reconfiguration (17:00-18: 00);
FIG. 8 is the result of the stored energy ES1 force during a fault;
fig. 9 is the energy storage ES2 contribution during a fault.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
As shown in fig. 1, the present invention provides an active power distribution network fault recovery method based on a hybrid solution strategy, which includes the following steps:
step S1, constructing an active power distribution network island division and network reconstruction unified model containing a distributed power supply and energy storage, wherein an objective function of the model considers equivalent power loss load, section switch operation and network loss cost;
step S2, solving the unified model by adopting a hybrid solving strategy based on the combination of breadth-first search, depth-first search and second-order cone optimization to obtain a line maintenance scheme;
and step S3, realizing the fault recovery of the active power distribution network based on the line maintenance scheme.
Step S1, a fault recovery strategy of matching island division and network reconstruction is adopted, after the active power distribution network fault occurs, on the basis of considering the load importance degree, the power supply requirement of a part of important loads is preferentially met through the island division, and meanwhile, a large number of unrecoverable nodes are prevented from being generated after the island division as much as possible, namely, the nodes which cannot recover the power supply through the network reconstruction; and then, based on a network topology structure after island division, power supply recovery is carried out on the residual load nodes by adopting network reconstruction, the system load flow and the network loss are optimized, and meanwhile, the operation times of switching are reduced as much as possible. The established target function of the unified model of the island division and the network reconstruction of the active power distribution network is the minimum comprehensive operation cost during the fault period of the active power distribution network, wherein equivalent power loss load, section switch operation and network loss cost are considered, and the target function is specifically expressed as follows:
Figure BDA0003033320730000051
in the formula: g1,tNetwork loss in a system t period; g2,tThe operation times of the switch are segmented for the t time period of the system; g3,tThe equivalent load recovery quantity of the system in the time period t is obtained; lambda [ alpha ]iIs the load weight of node i; pi,tThe active power of the load node i in the load t period is obtained;
Figure BDA0003033320730000055
representing a set of load nodes; upsilon is1、υ2、υ3Respectively a network loss cost coefficient, a switch operation cost coefficient and an equivalent power loss load cost coefficient, NTFor the number of time periods that the entire fault recovery lasts, Δ t is the duration of a single time period.
The network loss calculation method comprises the following steps:
Figure BDA0003033320730000052
in the formula: i isij,tIs the effective value R of the i-j current of the branch circuit in the t period of the systemijIs the resistance value of branch i-j; and omega is the set of all branches of the active power distribution network.
The method for calculating the operation times of the section switch comprises the following steps:
Figure BDA0003033320730000053
in the formula: decision variable alphaij,tFor the switch state of the line i-j in the period t, taking 0 to represent that the line i-j switch is disconnected, and taking 1 to represent that the line i-j switch is closed;
the method for calculating the equivalent load recovery quantity comprises the following steps:
Figure BDA0003033320730000054
in the formula: decision variable yi,tFor the load recovery state of the node i in the period t, taking 1 indicates that the load i is recovered in the period t, and taking 0 indicates that the load i is not recovered in the period t.
The constraint conditions of the active power distribution network islanding and network reconstruction unified model comprise node voltage and branch current constraint, node power balance constraint, DG power constraint, network structure constraint, energy storage charging and discharging state and power constraint, energy storage residual capacity constraint, capacitor switching constraint and fault maintenance strategy constraint.
(1) Node voltage and branch current constraints
After the load is recovered to be connected to the grid through an island division or network reconstruction mode, the system can operate normally and stably, and node voltage and branch current in the network need to meet certain constraint conditions, namely:
Figure BDA0003033320730000061
in the formula: vi max、Vi minRespectively representing the upper limit and the lower limit of the voltage of a node i; i isij,tThe current flowing through the branch i-j in the period t;
Figure BDA0003033320730000063
the maximum value of the current allowed to flow for branch i-j.
(2) Node power balance constraints
The key to meeting the requirement of power balance is the stable operation of the active power distribution network after the island division or the network reconstruction. As is apparent from kirchhoff's law, the sum of the powers flowing into a node must equal the sum of the powers flowing out of that node, and therefore the power balance constraint for the node should be satisfied, namely:
Figure BDA0003033320730000064
in the formula: vi,t、Vj,tThe voltages of the nodes i and j in the period t; gij、BijConductance and susceptance for branches i-j, respectively; deltaij,tThe phase angle difference of the i-j voltage of the branch circuit in the t period; and C (i) is a node set connected with the node i.
(3) DG power constraint
Because the output of Wind Turbine (WT) and Photovoltaic (PV) has strong intermittence and volatility, in order to enable the system to stably operate after island division and network reconstruction, the DG power constraint should be satisfied, that is:
Figure BDA0003033320730000065
in the formula: pDG,i,t、QDG,i,tActive output and reactive output of DG at a node i in a period t;
Figure BDA0003033320730000066
at node i for a period of tThe active and reactive power upper limits of the DG;
Figure BDA0003033320730000067
and the lower limit of the DG active power output and the reactive power output at the node i in the t period is shown.
(4) Network architecture constraints
In the fault recovery process, the active power distribution network needs to meet connectivity constraint and radial constraint by considering the fault recovery strategy of matching of island division and network reconstruction, namely:
Figure BDA0003033320730000068
in the formula: f. ofdiFor the virtual load of the node i, the virtual load function is to ensure that all load nodes meet connectivity constraint in the fault recovery process, and if the load nodes are isolated, the virtual power balance constraint of the node is not met, namely
Figure BDA0003033320730000071
Therefore, if the node virtual power balance constraint needs to be met, all load nodes need to be communicated, and meanwhile, as the number of the network lines of the power distribution network is equal to N-1, N is the number of the nodes, the connectivity constraint is met, namely the radial constraint is met, the virtual load and the virtual flow play a role in ensuring that the network connectivity constraint and the radial constraint are met. Generally, the unit 1, f is takenij,tIs the virtual flow passing through the branch i-j in the period t, NbIs the number of branches, NnIs the number of nodes, NsIs the number of power sources.
(5) Energy storage charging and discharging state and power constraint
The energy storage device can be used in the island division and network reconstruction process, but the charging and discharging power of the stored energy is not larger than the limit value, so that the charging and discharging state and power constraint of the stored energy are required to be met, namely:
Figure BDA0003033320730000072
in the formula: the decision variables are respectively energy storage charging and discharging states ye,i,tAnd energy storage charging and discharging power Pe,i,t。ye,i,tA variable 0-1 representing the charging and discharging state of the energy stored at the node i in the t period, wherein 0 is taken to represent charging, and 1 is taken to represent discharging;
Figure BDA0003033320730000073
respectively representing the maximum power of charging and discharging of the energy stored at the node i; pe,i,tRepresenting the power stored at node i that is charged or discharged during time t.
(6) Constraint of residual capacity of stored energy
The stored energy has certain capacity limitation, can not be excessively charged and discharged, and should satisfy the constraint of the residual capacity of the stored energy, namely:
Figure BDA0003033320730000074
in the formula:
Figure BDA0003033320730000075
the residual capacity of energy stored at the node i in the period t;
Figure BDA0003033320730000076
and
Figure BDA0003033320730000077
maximum and minimum capacity limits of energy storage at node i; etach、ηdisRespectively the charge-discharge efficiency of stored energy.
(7) Capacitor switching constraints
In order to deal with reactive demand of load when an active power distribution network islanding operates and the problem of under-voltage caused by reactive shortage after network reconstruction, a capacitor bank needs to be switched to carry out reactive compensation in the process of islanding division and network reconstruction fault recovery, and the switching constraint of a capacitor is met, namely:
Figure BDA0003033320730000078
in the formula:
Figure BDA0003033320730000081
the reactive compensation capacity of the capacitor at the node i in the period t;
Figure BDA0003033320730000082
representing the reactive compensation capacity put into a single capacitor; decision variables
Figure BDA0003033320730000083
The number of capacitors put into node i for time t;
Figure BDA0003033320730000084
the total number of capacitors available to be charged at node i.
(8) Troubleshooting policy constraints
When a plurality of lines in an active power distribution network have faults, the maintenance sequence of the line faults in each place needs to be reasonably arranged in a planned power failure period, and the specific method is to apply partial constraints to the switching state variables of each fault line in a network reconstruction and island division unified model, namely: and when the island division and the network reconstruction of each time interval are finished, repairing the rest fault lines by optimizing decision variables of the switches of each fault line, indirectly adjusting and optimizing the topological structure of the network, and finally determining the optimal fault maintenance strategy of the line in the whole fault time interval.
Figure BDA0003033320730000085
In the formula: decision variable betaij,tIndicating the state of each faulty line switch; omegaEIs the set of all fault lines; k is the maximum number of lines that can be serviced in a single time period.
As shown in fig. 2, in step S2, solving the unified model specifically includes:
step S201: reading the planned power failure time T of the fault, the DG output power in the period, the load prediction power and the energy storage charge state;
step S202: traversing each DG and the energy storage access node as root nodes, and determining a power circle by adopting a breadth-first search algorithm to obtain an island feasible solution;
step S203: obtaining an initial island division range by adopting a depth-first search algorithm according to the island feasible solution, and correcting the initial island division range according to an island fusion strategy to obtain an island division result in the time period;
the correcting the initial island division range according to the island fusion strategy specifically comprises the following steps: judging whether each island in the initial island division range has an intersection, if so, fusing the islands with the intersection, recording an equivalent DG and equivalent nodes directly connected with the equivalent DG, returning to the step S202, if not, judging whether adjacent islands meet the fusion constraint condition, if so, fusing, otherwise, canceling the fusion, and executing the step S204;
step S204: obtaining a unified model of island division and network reconstruction of the active power distribution network in the time period based on the island division result in the time period, the position of the operable interconnection switch and the network topology structure;
step S205: constructing an intermediate variable, and carrying out linearization treatment on the unified model to convert the unified model into a standard mixed integer second-order cone model;
step S206: solving the standard mixed integer second order cone model by adopting a commercial solver, wherein the commercial solver which can be adopted comprises an MOSEK algorithm package in a YALMIP toolbox and the like;
step S207: and judging whether the calculation of all time intervals is finished, if so, outputting a final line maintenance scheme, otherwise, returning to the step S201 to calculate the next time interval.
In step S205, a great number of quadratic terms and trigonometric function terms exist in the unified model of island division and network reconstruction, which is an MINLP problem, and a second-order cone relaxation technique is adopted to perform convex relaxation on the model. Quadratic terms and trigonometric function terms existing in the active power distribution network island division and network reconstruction unified model, as shown in formulas (4) and (6), are non-convex and are difficult to directly solve mathematically. According to the invention, convex relaxation processing is carried out on the unified model of island division and network reconstruction by introducing an intermediate variable method and utilizing a second-order cone relaxation technology, and further, a global optimal solution can be rapidly obtained by adopting a mature commercial solver. The introduced intermediate variables are shown in formulas (13) to (17).
Figure BDA0003033320730000091
Figure BDA0003033320730000092
Cij,t＝Vi,tVj,tcos(δij,t) (15)
Dij,t＝Vi,tVj,tsin(δij,t) (16)
Figure BDA0003033320730000093
Because the quadratic term is contained in the formula (17), the model still has non-convexity, and the model is further relaxed as shown in the formula (18).
Figure BDA0003033320730000094
The second-order taper form of the modified expression (18) is shown as the expression (19).
Figure BDA0003033320730000095
The network loss formula (4) containing a square term and the node power balance constraint formula (6) containing the square term and a trigonometric function term in the original model are respectively shown in formulas (20) to (22) after second-order cone relaxation.
Figure BDA0003033320730000096
Figure BDA0003033320730000097
Figure BDA0003033320730000101
At the moment, the feasible region is relaxed into a whole second-order cone, the search space is limited in a convex cone range, the feasible region is convex, and the solution can be completed by adopting a commercial solver.
The above functions, if implemented in the form of software functional units and sold or used as a separate product, may be stored in a computer-readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
In another embodiment, an active power distribution network fault recovery system based on a hybrid solution strategy is provided, which includes: one or more processors, memory, and one or more programs stored in the memory, the one or more programs including instructions for performing the hybrid solution strategy-based proactive power distribution network fault recovery method described above.
Examples
In this embodiment, an IEEE 33 node active power distribution network including DG and Energy Storage (ES) is adopted, and the structure thereof is shown in fig. 3, where node numbers are marked in the figure; the maximum load of the system is 3715kW +2300 kvar. The load class parameters are shown in table 1, and the specific access nodes and rated power of each DG and the stored energy are shown in tables 2 and 3.
TABLE 1 node load level parameter
Figure BDA0003033320730000102
TABLE 2 DG rating and Access Point
Figure BDA0003033320730000103
Figure BDA0003033320730000111
Table 3 energy storage access points and parameters
Figure BDA0003033320730000112
In order to verify the effectiveness of the active power distribution network fault recovery method, permanent faults of the lines 6-7, 10-11, 15-16, 22-23 and 26-27 are set when a power distribution network has a major accident that multiple lines have faults simultaneously under an extreme weather condition, and the fault power failure time interval is 14:00-18: 00. In this embodiment, the maximum number of maintenance lines in a single time period is 1, and after island division and network reconstruction in each time period are finished, on the premise that the fault maintenance policy constraint of the formula (12) is satisfied, the fault repair sequence is optimized by adjusting the switching decision variable of the fault line, so as to determine the optimal fault maintenance policy. The main objective of the fault recovery strategy for matching the island division and the network reconstruction is to recover the load power supply as much as possible, and other objective functions are used for assisting in optimizing the network running state.
By adopting the fault recovery strategy of matching the island division and the network reconstruction provided by the invention, and considering the fault overhaul strategy constraint, before the island division and the network reconstruction are carried out in each time period, the switching decision variable of a fault line is firstly adjusted through optimization, the network topology structure is adjusted, the finally determined line overhaul strategies are 22-23, 10-11, 15-16 and 6-7 in sequence, and the fault recovery result in each time period is shown in fig. 4-9 and table 4. It can be seen that the ES1 has a large rated power and is cooperated with the WT2 to participate in islanding, while the ES2 has a small rated capacity and can only play a role in network reconfiguration, and the method of the present invention can realize the restoration of power supply of all the class-1 load nodes 8, 9, 16, 24, 30 and 31.
TABLE 4 time period failure recovery results
Figure BDA0003033320730000113
In order to verify the superiority of the fault recovery strategy provided by the invention, the operation results of the fault recovery strategy, which is not matched with the islanding and the network reconstruction but considers the fault maintenance strategy, and the operation results of the fault recovery strategy, which is matched with the islanding and the network reconstruction but does not have the fault maintenance strategy, are respectively compared, and the results are shown in table 5.
TABLE 5 Fault resilient policy comparison
Figure BDA0003033320730000121
It can be seen that, by using the strategy 1, that is, islanding and network reconstruction are not mutually matched, although the load recovered through islanding reaches the maximum, since islanding and network reconstruction are independently performed, only the local optimal solution of islanding is obtained, so that part of nodes cannot recover power supply through network reconstruction, and the power supply recovery rate is only 87.15%. And a strategy 2 is adopted, namely island division is matched with network reconstruction for power supply recovery, but no fault maintenance strategy is adopted, the sequence of repairing the line is random, and the power supply recovery rate is 92.43%. Compared with the strategy 1, the strategy 2 can obtain that the active power distribution network is subjected to fault recovery together in a mode of considering the matching of the island division and the network reconstruction, the island division and the network reconstruction are carried out simultaneously, namely, the load which cannot be recovered in the reconstruction process is considered, and the result shows that the power loss load electric quantity is reduced by 508.7 kW.h, so that the superiority of the unified model of the island division and network reconstruction is proved. When the strategy 3 is adopted, namely, the power supply recovery is carried out by matching the island division with the network reconstruction and the fault maintenance strategy is considered, the power supply recovery rate can reach 97.27%, and the power loss load electric quantity is respectively reduced by 974.4 kW.h and 465.7 kW.h compared with the strategies 1 and 2, which shows that the fault maintenance strategy adopted by the invention can more reasonably arrange the fault repair process, thereby further improving the power supply recovery rate.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.

Claims (10)

1. A hybrid solution strategy-based active power distribution network fault recovery method is characterized by comprising the following steps:
step S1, constructing an active power distribution network island division and network reconstruction unified model containing a distributed power supply and energy storage, wherein an objective function of the model considers equivalent power loss load, section switch operation and network loss cost;
step S2, solving the unified model by adopting a hybrid solving strategy based on the combination of breadth-first search, depth-first search and second-order cone optimization to obtain a line maintenance scheme;
and step S3, realizing the fault recovery of the active power distribution network based on the line maintenance scheme.
2. The hybrid solution strategy-based active distribution network fault recovery method according to claim 1, wherein the objective function is expressed as:
Figure FDA0003033320720000011
in the formula: g1,tNetwork loss in a system t period; g2,tThe operation times of the switch are segmented for the t time period of the system; g3,tThe equivalent load recovery quantity of the system in the time period t is obtained; lambda [ alpha ]iIs the load weight of node i; pi,tThe active power of the load node i in the load t period is obtained;
Figure FDA0003033320720000012
representing a set of load nodes; upsilon is1、υ2、υ3Respectively a network loss cost coefficient, a switch operation cost coefficient and an equivalent power loss load cost coefficient, NTFor the number of time periods that the entire fault recovery lasts, Δ t is the duration of a single time period.
3. The active power distribution network fault recovery method based on the hybrid solution strategy as claimed in claim 2, wherein the network loss is calculated by:
Figure FDA0003033320720000013
in the formula: i isij,tIs the effective value R of the i-j current of the branch circuit in the t period of the systemijIs the resistance value of branch i-j; omega is a set of all branches of the active power distribution network;
the method for calculating the operation times of the section switch comprises the following steps:
Figure FDA0003033320720000014
in the formula: decision variable alphaij,tFor the switch state of the line i-j in the period t, taking 0 to represent that the line i-j switch is disconnected, and taking 1 to represent that the line i-j switch is disconnectedClosing;
the method for calculating the equivalent load recovery quantity comprises the following steps:
Figure FDA0003033320720000015
in the formula: decision variable yi,tFor the load recovery state of the node i in the period t, taking 1 indicates that the load i is recovered in the period t, and taking 0 indicates that the load i is not recovered in the period t.
4. The active power distribution network fault recovery method based on the hybrid solution strategy of claim 1, wherein the constraint conditions of the active power distribution network island division and network reconstruction unified model comprise node voltage and branch current constraints, node power balance constraints, DG power constraints, network structure constraints, energy storage charge-discharge states and power constraints, energy storage residual capacity constraints, capacitor switching constraints and fault overhaul strategy constraints.
5. The active power distribution network fault recovery method based on the hybrid solution strategy as claimed in claim 1, wherein in step S2, solving the unified model specifically comprises:
step S201: reading the planned power failure time T of the fault, the DG output power in the period, the load prediction power and the energy storage charge state;
step S202: traversing each DG and the energy storage access node as root nodes, and determining a power circle by adopting a breadth-first search algorithm to obtain an island feasible solution;
step S203: obtaining an initial island division range by adopting a depth-first search algorithm according to the island feasible solution, and correcting the initial island division range according to an island fusion strategy to obtain an island division result in the time period;
step S204: obtaining a unified model of island division and network reconstruction of the active power distribution network in the time period based on the island division result in the time period, the position of the operable interconnection switch and the network topology structure;
step S205: constructing an intermediate variable, and carrying out linearization treatment on the unified model to convert the unified model into a standard mixed integer second-order cone model;
step S206: solving the standard mixed integer second order cone model by adopting a commercial solver;
step S207: and judging whether the calculation of all time intervals is finished, if so, outputting a final line maintenance scheme, otherwise, returning to the step S201 to calculate the next time interval.
6. The active power distribution network fault recovery method based on the hybrid solution strategy according to claim 5, wherein the correcting the initial island division range according to the island fusion strategy specifically comprises:
and judging whether each island in the initial island division range has intersection, if so, fusing the islands with the intersection, recording the equivalent DG and equivalent nodes directly connected with the equivalent DG, returning to the step S202, if not, judging whether the adjacent islands meet the fusion constraint condition, if so, fusing, otherwise, canceling the fusion, and executing the step S204.
7. The hybrid solution strategy based active power distribution network fault recovery method of claim 5, wherein the business solver comprises a YALMIP tool box.
8. The active power distribution network fault recovery method based on the hybrid solution strategy as claimed in claim 5, wherein in step S205, convex relaxation is performed on the unified model by using a second-order cone relaxation technique, so as to convert the unified model into the standard mixed integer second-order cone model.
9. The active power distribution network fault recovery method based on the hybrid solution strategy is characterized in that the feasible region of the standard mixed integer second-order cone model is relaxed into an entire second-order cone, and the search space is in the convex cone range.
10. The utility model provides an initiative distribution network fault recovery system based on mix solution strategy which characterized in that includes:
one or more processors, memory, and one or more programs stored in the memory, the one or more programs including instructions for performing the hybrid solution strategy-based proactive power distribution network fault recovery method of any of claims 1-9.
CN202110436401.1A 2021-04-22 2021-04-22 Active power distribution network fault recovery method and system based on hybrid solving strategy Active CN112909942B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110436401.1A CN112909942B (en) 2021-04-22 2021-04-22 Active power distribution network fault recovery method and system based on hybrid solving strategy

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110436401.1A CN112909942B (en) 2021-04-22 2021-04-22 Active power distribution network fault recovery method and system based on hybrid solving strategy

Publications (2)

Publication Number Publication Date
CN112909942A true CN112909942A (en) 2021-06-04
CN112909942B CN112909942B (en) 2023-09-26

Family

ID=76108862

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110436401.1A Active CN112909942B (en) 2021-04-22 2021-04-22 Active power distribution network fault recovery method and system based on hybrid solving strategy

Country Status (1)

Country Link
CN (1) CN112909942B (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113991737A (en) * 2021-11-02 2022-01-28 国网河北省电力有限公司电力科学研究院 Active power distribution network robust optimization fault recovery method for renewable energy grid connection
CN113991671A (en) * 2021-12-02 2022-01-28 永嘉县电力实业有限公司 Fault self-healing recovery method for power distribution network at tail end of mountain area
CN114362155A (en) * 2021-12-29 2022-04-15 国网宁夏电力有限公司电力科学研究院 Active power distribution network reconstruction method considering active management measures and demand response
CN117394353A (en) * 2023-12-08 2024-01-12 国网天津市电力公司电力科学研究院 Power distribution network load transferring and recovering method and device
CN117810996A (en) * 2024-03-01 2024-04-02 南京师范大学 Active power distribution network fault recovery method considering island division and network reconstruction

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170070044A1 (en) * 2015-09-06 2017-03-09 Tsinghua University Robust restoration method for active distribution network
CN109120009A (en) * 2018-09-11 2019-01-01 国网天津市电力公司电力科学研究院 The active distribution network fault recovery method that meter and distributed generation resource power output change at random
CN109586277A (en) * 2018-11-01 2019-04-05 国网新疆电力有限公司检修公司 Multi-agent system distributed and coordinated control system and its distribution network failure restoration methods
CN110350508A (en) * 2019-05-16 2019-10-18 东南大学 Method that is a kind of while considering the active distribution network fault recovery unified model that reconstruct is divided with isolated island
CN111313557A (en) * 2020-03-25 2020-06-19 马瑞 Intelligent self-healing switch cabinet based on 5G internet of things

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170070044A1 (en) * 2015-09-06 2017-03-09 Tsinghua University Robust restoration method for active distribution network
CN109120009A (en) * 2018-09-11 2019-01-01 国网天津市电力公司电力科学研究院 The active distribution network fault recovery method that meter and distributed generation resource power output change at random
CN109586277A (en) * 2018-11-01 2019-04-05 国网新疆电力有限公司检修公司 Multi-agent system distributed and coordinated control system and its distribution network failure restoration methods
CN110350508A (en) * 2019-05-16 2019-10-18 东南大学 Method that is a kind of while considering the active distribution network fault recovery unified model that reconstruct is divided with isolated island
CN111313557A (en) * 2020-03-25 2020-06-19 马瑞 Intelligent self-healing switch cabinet based on 5G internet of things

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113991737A (en) * 2021-11-02 2022-01-28 国网河北省电力有限公司电力科学研究院 Active power distribution network robust optimization fault recovery method for renewable energy grid connection
CN113991737B (en) * 2021-11-02 2023-09-01 国网河北省电力有限公司电力科学研究院 Robust optimization fault recovery method for active power distribution network with renewable energy grid connection
CN113991671A (en) * 2021-12-02 2022-01-28 永嘉县电力实业有限公司 Fault self-healing recovery method for power distribution network at tail end of mountain area
CN114362155A (en) * 2021-12-29 2022-04-15 国网宁夏电力有限公司电力科学研究院 Active power distribution network reconstruction method considering active management measures and demand response
CN114362155B (en) * 2021-12-29 2023-11-07 国网宁夏电力有限公司电力科学研究院 Active power distribution network reconstruction method considering active management measures and demand response
CN117394353A (en) * 2023-12-08 2024-01-12 国网天津市电力公司电力科学研究院 Power distribution network load transferring and recovering method and device
CN117394353B (en) * 2023-12-08 2024-05-14 国网天津市电力公司电力科学研究院 Power distribution network load transferring and recovering method and device
CN117810996A (en) * 2024-03-01 2024-04-02 南京师范大学 Active power distribution network fault recovery method considering island division and network reconstruction
CN117810996B (en) * 2024-03-01 2024-05-17 南京师范大学 Active power distribution network fault recovery method considering island division and network reconstruction

Also Published As

Publication number Publication date
CN112909942B (en) 2023-09-26

Similar Documents

Publication Publication Date Title
Wong et al. Review on the optimal placement, sizing and control of an energy storage system in the distribution network
CN112909942A (en) Active power distribution network fault recovery method and system based on hybrid solution strategy
CN111478358A (en) Power distribution network robust recovery decision method considering distributed power supply uncertainty
CN103904646A (en) Micro-grid multi-objective energy optimization method taking three-phase currents into consideration
Zhang et al. Research on bi-level optimized operation strategy of microgrid cluster based on IABC algorithm
CN110676839A (en) Method and system for evaluating reliability of alternating current-direct current hybrid power distribution network
Kaysal et al. Hierarchical energy management system with multiple operation modes for hybrid DC microgrid
CN114725926A (en) Toughness-improvement-oriented black start strategy for distributed resource-assisted main network key nodes
CN111931355A (en) Power distribution network and energy storage joint planning method considering N-1 safety criterion
CN114865625A (en) Power distribution network fault recovery method comprising microgrid
CN111224422A (en) Reliability-based micro-grid distributed power supply configuration method and system
CN113361078A (en) Power distribution network cloud edge cooperative regulation and control method considering photovoltaic power generation uncertainty
CN112910000A (en) Dynamic island division method for power distribution network comprising distributed power supply
CN116882139A (en) Active power distribution network element repairing method and system considering network reconstruction and fault rush-repair rolling optimization
CN115719967A (en) Active power distribution network energy storage device optimal configuration method for improving power supply reliability
CN112909935B (en) Dynamic reconstruction method for power distribution network fault recovery
Sun et al. Power recovery strategy of distribution network with distributed power
Elgamal et al. Optimal operation of a hybrid-energy microgrid with energy storage system
Kumar et al. Evaluation of DG impacts on distribution networks
Zhou et al. MILP-based splitting strategy searching considering island connectivity and voltage stability margin
Wu et al. A two-step island partition strategy of active distribution system
Zhang et al. Calculation Method for Maximum Accommodation Capacity of Distributed Photovoltaic in Distribution Network Considering Various Electrical Constraints
CN111106622A (en) Active power distribution network power supply recovery method based on RMPC
Wang et al. Fault Recovery Strategy of Distribution Network with Distributed Generation Based on Island Division
Zhang et al. Bi-Level Energy Management Strategy for Microgrid Cluster Considering Multi-Agent Game with Incomplete Information and Source-Load Uncertainty

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant