CN112910000B - Dynamic island division method for power distribution network comprising distributed power supply - Google Patents

Dynamic island division method for power distribution network comprising distributed power supply Download PDF

Info

Publication number
CN112910000B
CN112910000B CN202110148677.XA CN202110148677A CN112910000B CN 112910000 B CN112910000 B CN 112910000B CN 202110148677 A CN202110148677 A CN 202110148677A CN 112910000 B CN112910000 B CN 112910000B
Authority
CN
China
Prior art keywords
node
island
nodes
period
power
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.)
Active
Application number
CN202110148677.XA
Other languages
Chinese (zh)
Other versions
CN112910000A (en
Inventor
柳卫明
孙玉波
王振春
涂承谦
张林垚
林毅
周城
吴桂联
罗超
吴雄
伍仰金
高勉伟
杨丹丹
许晓亮
林锦灿
张婷婷
倪识远
陈浩
宋倩芸
林婷婷
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.)
State Grid Fujian Electric Power Co Ltd
Economic and Technological Research Institute of State Grid Fujian Electric Power Co Ltd
Ningde Power Supply Co of State Grid Fujian Electric Power Co Ltd
Original Assignee
State Grid Fujian Electric Power Co Ltd
Economic and Technological Research Institute of State Grid Fujian Electric Power Co Ltd
Ningde Power Supply Co of State Grid Fujian 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 State Grid Fujian Electric Power Co Ltd, Economic and Technological Research Institute of State Grid Fujian Electric Power Co Ltd, Ningde Power Supply Co of State Grid Fujian Electric Power Co Ltd filed Critical State Grid Fujian Electric Power Co Ltd
Priority to CN202110148677.XA priority Critical patent/CN112910000B/en
Publication of CN112910000A publication Critical patent/CN112910000A/en
Application granted granted Critical
Publication of CN112910000B publication Critical patent/CN112910000B/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
    • H02J3/38—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
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q10/00—Administration; Management
    • G06Q10/04—Forecasting or optimisation specially adapted for administrative or management purposes, e.g. linear programming or "cutting stock problem"
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q50/00—Systems or methods specially adapted for specific business sectors, e.g. utilities or tourism
    • G06Q50/06—Electricity, gas or water supply
    • 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]
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/70—Smart grids as climate change mitigation technology in the energy generation sector
    • 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
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications

Abstract

The invention relates to a method for dividing a power distribution network dynamic island containing a distributed power supply, which comprises the following steps: acquiring initial data, calculating an island feasible solution in the period of time by adopting a breadth-first search algorithm according to the initial data, dividing an island range by adopting a depth-first search algorithm according to the island feasible solution in the period of time, optimizing the island range by adopting an island fusion inspection strategy, judging whether the optimal island range in all the periods of time is determined, calculating the energy storage charge state in the next period of time if the optimal island range in all the periods of time is not determined, determining the optimal island range in the next period of time until the optimal island range in all the periods of time is determined, outputting the dynamic island division scheme set, and finishing the island division. The method fully considers the balance problem of DG generated energy and load power consumption, and dynamically divides the island so as to ensure the safety and reliability of the island operation; and the island is fused, the utilization rate of the DG is improved, and the power supply recovery range is further expanded.

Description

Dynamic island division method for power distribution network comprising distributed power supply
Technical Field
The invention relates to a dynamic islanding method for a power distribution network comprising distributed power supplies, and belongs to the technical field of islanding of power distribution networks.
Background
In recent years, with the rapid development of economy, the problems of energy shortage, environmental pollution and the like in China are increasingly aggravated, under the support of national policies, the permeability of a distributed power supply in a power distribution network is gradually increased, and after a fault occurs, a part of important loads can be recovered to supply power by forming an isolated island, so that the power supply reliability of the power distribution network is improved. However, the output of the distributed power supply has the characteristics of intermittence and fluctuation, and the safe and stable operation of the power grid is threatened. In summary, it is necessary to research a dynamic islanding strategy of a power distribution network, which comprehensively considers randomness of distributed power output and load fluctuation characteristics.
At present, a plurality of island division researches aiming at fault recovery of an active power distribution network after a fault exist. The island division method mainly uses power balance as a division principle, solves an island range by taking priority to guarantee that important loads are supplied with power and as much as possible load restoration power supply as a target, but mostly adopts a static island division model in the prior art, namely, a Distributed power supply output and a load power consumption fixed value are taken, randomness and volatility are rarely considered, only power balance, electrical safety and the like are taken as constraints, the electric quantity balance problem of DG (Distributed Generation) generated energy and load power consumption is ignored, the safety and reliability of island operation are difficult to guarantee, island fusion is not considered, the island range is not adjusted and optimized, partial feasible solutions are ignored, and the utilization rate of the Distributed power supply is low. Therefore, in order to improve the power supply reliability of the power distribution network, the research on the multi-period dynamic island division strategy of the power distribution network with the distributed power supply is significant.
Disclosure of Invention
In order to overcome the problems, the invention provides a method for dividing a power distribution network dynamic island containing a distributed power supply, which fully considers the balance problem of DG power generation and load power consumption and dynamically divides the island so as to ensure the safety and reliability of island operation; and the island is fused, the utilization rate of the DG is improved, and the power supply recovery range is further expanded.
The technical scheme of the invention is as follows:
a method for dynamic island division of a power distribution network comprising a distributed power supply comprises the following steps:
acquiring initial data, wherein the initial data comprises fault position information, planned power failure time information, power distribution network parameters during fault, load grade parameters, load power prediction and energy storage charge state in the period;
calculating the feasible solution of the island in the period, taking load nodes connected with the distributed power supply and the energy storage as root nodes according to the initial data, and determining the range of each power circle by adopting a breadth-first search algorithm on the premise of meeting related constraints to obtain the feasible solution of the island in the period;
dividing an island range, and searching a preliminary island division range of the time period corresponding to the maximum equivalent load recovery scheme by adopting a depth-first search algorithm on the premise of meeting related constraints according to the feasible island solution of the time period;
optimizing an island division range, and adjusting and optimizing the initial island division range in the period by adopting an island fusion inspection strategy according to the initial island division range in the period to determine the optimal island division range in the period;
and judging whether the optimal islanding ranges of all the time periods are determined, if not, calculating the energy storage charge state of the next time period, determining the optimal islanding ranges of the next time period until the optimal islanding ranges of all the time periods are determined, bringing the optimal islanding ranges of all the time periods into a dynamic islanding scheme set, outputting the dynamic islanding scheme set, and finishing the islanding.
The specific operation of determining the range of each power circle by using the breadth-first search algorithm is as follows:
setting an array a for indicating whether the node is searched; searching all root nodes at the current moment by taking the load nodes connected with the distributed power supply and the energy storage as root nodes, and recording the root nodes as searched nodes in the array a; taking a distributed power supply and energy storage output connected with a root node as a power circle radius of the root node, and if the power circle radius is larger than the load power of the root node, taking the root node as a feasible node and recording the feasible node into a queue A;
searching all lower-layer nodes adjacent to the root node in the network, and recording the lower-layer nodes as searched nodes in the array a; if the sum of the load power of a certain lower-layer node and the load power of a node connected to the upper layer of the node is smaller than the power circle radius of the root node to which the node belongs, recording the node as a feasible node into the queue A, otherwise, not operating the node and stopping searching the node connected to the lower layer of the node;
starting from the lower-layer node recorded in the queue A, searching all nodes of the lower layer which are not searched, recording the nodes of the lower layer as searched nodes in the array a, recording the nodes into the queue A if the sum of the load power of a certain node and the nodes connected with the upper layer is smaller than the power circle radius of the root node to which the node belongs, and otherwise, not operating the nodes and stopping searching the nodes connected with the lower layer; and by analogy, searching layer by layer until all nodes in the network are searched, wherein the nodes contained in the queue A are feasible solutions of island division.
The depth-first search algorithm determines a preliminary island division range by taking the maximum equivalent load recovery quantity as a target; the objective function established with the maximum equivalent load recovery amount is as follows:
Figure BDA0002931256580000021
in the formula, Nt，LRepresenting the total number of load nodes contained in the island system at the time t; x is the number ofiTaking a value of 1 or 0 when xiWhen the value is equal to 1, indicating that the node i participates in the islanding, otherwise, not participating in the islanding; c. CiReflecting the load weight of the node i, wherein the higher the priority level of the load is, the larger the weight is; pL,i,tThe active power loaded by the node i at the moment t.
When the preliminary island division range of the time period corresponding to the maximum equivalent load recovery scheme is searched by adopting the depth-first search algorithm, various electrical constraint conditions are considered, wherein the constraint conditions of the island division comprise,
firstly, node voltage and branch current constraint:
Figure BDA0002931256580000031
in the formula: vi,tIs the voltage at node i at time t,Vi max、Vi minrespectively representing the upper limit and the lower limit of the voltage of a node i; I.C. Aij,tFor the current flowing on branch i-j during time t,
Figure BDA0002931256580000032
allowing the maximum current for branch i-j;
node power balance constraint:
Figure BDA0002931256580000033
in the formula: vi,t、Vj,tThe voltages of the nodes i and j in the period t; alpha is 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; p isis,t、Qis,tRespectively injecting active power and reactive power into a node i at the moment t; gij、BijFor the conductance and susceptance, delta, of the branches i-jij,tThe voltage phase angle difference of the branch i-j is t time period; c (i) is a node set connected with the node i;
③ DG Power constraint:
Figure BDA0002931256580000034
in the formula: pDG,i,t、QDG,i,tActive output and reactive output of DG at a node i in a period t;
Figure BDA0002931256580000035
the upper limit of active output and reactive output of DG at a node i in the t period;
Figure BDA0002931256580000036
the lower limit of active output and reactive output of DG at a node i in the t period;
network structure constraint:
Figure BDA0002931256580000037
in the formula: f. ofdiFor the virtual load of node i, the units 1, f can be 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, NsThe number of power supplies;
energy storage charging and discharging state and power constraint:
Figure BDA0002931256580000041
in the formula:
Figure BDA0002931256580000042
respectively representing 0-1 variables of the charge and discharge state of the energy stored at the node i in the period t;
Figure BDA0002931256580000043
respectively representing the maximum power of charging and discharging of the energy stored at the node i;
Figure BDA0002931256580000044
representing the charging and discharging power of the energy storage at the node i in the t period;
sixthly, energy storage residual capacity constraint:
Figure BDA0002931256580000045
in the formula:
Figure BDA0002931256580000046
the residual capacity of energy stored at the node i in the period t;
Figure BDA0002931256580000047
and
Figure BDA0002931256580000048
maximum and minimum capacity limits of energy storage at node i; etach、ηdisRespectively the charge and discharge efficiency of the stored energy;
seventh, capacitor switching constraint:
Figure BDA0002931256580000049
in the formula:
Figure BDA00029312565800000410
for the reactive compensation capacity of the capacitor at node i during the period t,
Figure BDA00029312565800000411
representing the compensation capacity put into a single capacitor,
Figure BDA00029312565800000412
the number of capacitors switched at node i for the t period,
Figure BDA00029312565800000413
the total number of capacitors available for switching at node i.
The island fusion inspection strategy is adopted to adjust and optimize the island fusion inspection strategy, and the specific operation of determining the optimal island division range in the period is as follows:
judging whether the primary island division range has an intersection or not, and clearing the intersection island division result to obtain an equivalent node; the removing specifically includes that when island division results corresponding to two adjacent distributed power supplies have an intersection, all nodes on a communication path between distributed power supply access nodes in an island are combined into an equivalent node, distributed power supplies in the two islands are combined into an equivalent distributed power supply, and if a branch exists on the communication path between the distributed power supply access nodes, the branch is directly connected with the equivalent node;
determining a preliminary island division range according to breadth-first search and depth-first search by taking the equivalent node as a root node, judging whether the preliminary island division range has an intersection, and removing island division results with the intersection to obtain the equivalent node; repeating the steps until all the islands have no intersection, and obtaining an optimal island division range without intersection;
fusing any two adjacent islands according to the optimal island division range, and outputting an island division result in the time period; the merging is to merge all nodes in the line between the two island ranges into the island range, if the merged island meets the constraint condition of island division, island merging operation is carried out, otherwise, island merging is cancelled, and the optimal island division range of the time period is obtained.
The invention has the following beneficial effects:
1. the island division method considers the randomness and the volatility of the power grid, dynamically divides the power grid according to the electric quantity balance of the generated energy of the distributed power supply and the electric quantity of the load power consumption, obtains island division ranges in different time periods, and ensures the safety and the reliability of island operation.
2. According to the island division method, the island division result is adjusted and optimized by utilizing a fusion inspection strategy in consideration of the condition of island fusion, islands with intersection in island division ranges are fused, and then adjacent islands are fused, so that the utilization rate of the distributed power supply is improved.
Drawings
FIG. 1 is a flow chart of the present invention.
FIG. 2 is a flow chart of an embodiment of the present invention.
FIG. 3 is an island fusion process when the present invention island division has an intersection.
FIG. 4 is an island fusion process when there is no intersection in the island division of the present invention.
Detailed Description
The invention is described in detail below with reference to the figures and the specific embodiments.
A dynamic islanding method for a power distribution network comprising a distributed power supply comprises the following steps:
acquiring initial data, wherein the initial data comprises fault position information, planned power failure time information, power distribution network parameters during fault, load grade parameters, load power prediction and energy storage charge state in the period; the fault position information is network information of a power grid fault; the planned power failure time information comprises total power failure time of a fault plan, a planned average time period and the current time; the load type represents the priority level of the load, and the load type is divided into a first type load, a second type load and a third type load in the embodiment of the invention;
calculating the feasible solution of the island in the period, taking load nodes connected with the distributed power supply and the energy storage as root nodes according to the initial data, and determining the range of each power circle by adopting a breadth-first search algorithm on the premise of meeting related constraints to obtain the feasible solution of the island in the period;
dividing an island range, and searching a preliminary island division range of the time period corresponding to the maximum equivalent load recovery scheme by adopting a depth-first search algorithm on the premise of meeting related constraints according to the feasible island solution of the time period;
optimizing an island division range, and adjusting and optimizing the initial island division range in the period by adopting an island fusion inspection strategy according to the initial island division range in the period to determine the optimal island division range in the period;
and judging whether the optimal islanding ranges of all the time periods are determined, if not, calculating the energy storage charge state of the next time period, determining the optimal islanding ranges of the next time period until the optimal islanding ranges of all the time periods are determined, bringing the optimal islanding ranges of all the time periods into a dynamic islanding scheme set, outputting the dynamic islanding scheme set, and finishing the islanding.
The specific operation of determining the range of each power circle by using the breadth-first search algorithm is as follows:
setting an array a for indicating whether the node is searched; searching all root nodes at the current moment by taking the load nodes connected with the distributed power supply and the energy storage as root nodes, and recording the root nodes as searched nodes in the array a; taking a distributed power supply and energy storage output connected with a root node as a power circle radius of the root node, and if the power circle radius is larger than the load power of the root node, taking the root node as a feasible node and recording the feasible node into a queue A;
searching all lower-layer nodes adjacent to the root node in the network, and recording the lower-layer nodes as searched nodes in the array a; if the sum of the load power of a certain lower-layer node and the load power of the node connected to the upper layer is smaller than the power circle radius of the root node to which the node belongs, recording the node as a feasible node into the queue A, otherwise, not operating the node and stopping searching the node connected to the lower layer;
starting from the lower node recorded in the queue A, searching all nodes of which the lower layer is not searched, recording the nodes of the lower layer as searched nodes in the array a, recording the nodes of the lower layer into the queue A if the sum of the load power of a certain node and the nodes connected to the upper layer is smaller than the power circle radius of the root node to which the node belongs, and otherwise, not operating the nodes and stopping searching the nodes connected to the lower layer; and by analogy, searching layer by layer until all nodes in the network are searched, wherein the nodes contained in the queue A are feasible solutions of island division.
The depth-first search algorithm determines a preliminary island division range by taking the maximum equivalent load recovery quantity as a target; the objective function established with the maximum equivalent load recovery amount is as follows:
Figure BDA0002931256580000061
in the formula, Nt，LRepresenting the total number of load nodes contained in the island system at the time t; x is the number ofiTaking a value of 1 or 0 when xiWhen the number is 1, indicating that the node i participates in the islanding, otherwise, not participating in the islanding; c. CiThe load weight of the node i is reflected, the higher the priority level of the load is, the larger the weight is, the first-class load weight is 1, the second-class load weight is 0.5, and the third-class load weight is 0.1 in the embodiment of the invention; pL,i,tThe active power loaded by the node i at the moment t.
When the preliminary island division range of the time period corresponding to the maximum equivalent load recovery scheme is searched by adopting the depth-first search algorithm, various electrical constraint conditions are considered, wherein the constraint conditions of the island division comprise,
firstly, node voltage and branch current are constrained, and after a load is recovered and connected to the grid in an island and reconstruction mode, in order to ensure that a system can normally and stably operate, the node voltage and the branch current in a network need to meet certain constraint conditions, namely:
Figure BDA0002931256580000062
in the formula: vi,tIs the voltage of node i at time t, Vi max、Vi minRespectively representing the upper limit and the lower limit of the voltage of a node i; i isij,tFor the current flowing on branch i-j during time t,
Figure BDA0002931256580000071
allowing the maximum current for branch i-j;
secondly, node power balance constraint is carried out, and the key of stable operation of an island and an active power distribution network after reconstruction is to meet the requirement of power balance. As known from kirchhoff's law, the sum of the powers flowing into a node must be equal to the sum of the powers flowing out of the node, and therefore the power balance constraint of the node should be satisfied, namely:
Figure BDA0002931256580000072
in the formula: vi,t、Vj,tThe voltages of the nodes i and j in the period t; alpha (alpha) ("alpha")ij,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; pis,t、Qis,tRespectively injecting active power and reactive power into a node i at the moment t; gij、BijFor the conductance and susceptance, delta, of the branches i-jij,tThe voltage phase angle difference of the branch i-j in the period t; c (i) is a node set connected with the node i;
DG power restraint, because wind-powered electricity generation and photovoltaic's the output has stronger intermittent type nature and volatility, want to make the system can the steady operation after island division and network reconstruction, should satisfy DG power restraint, promptly:
Figure BDA0002931256580000073
in the formula: pDG,i,t、QDG,i,tActive output and reactive output of DG at a node i in a period t;
Figure BDA0002931256580000074
the upper limit of active output and reactive output of DG at a node i in the t period;
Figure BDA0002931256580000075
the lower limit of active output and reactive output of DG at a node i in the t period;
and fourthly, network structure constraint, wherein the active power distribution network is generally in closed-loop design and open-loop operation. Therefore, in the fault recovery process, considering the fault recovery strategy that island division is matched with network reconstruction, the active power distribution network needs to satisfy connectivity constraint and radial constraint, that is:
Figure BDA0002931256580000076
in the formula: f. ofdiFor the virtual load of node i, the units 1, f can be 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, NsThe number of power supplies;
energy storage charge-discharge state and power constraint, energy storage devices can be used in the process of island division and network reconstruction, but the charge-discharge power of energy storage is not greater than the limit value, so that the energy storage charge-discharge state and power constraint are required to be met, namely:
Figure BDA0002931256580000081
in the formula:
Figure BDA0002931256580000082
respectively representing 0-1 variables of the charge and discharge state of the energy stored at the node i in the period t;
Figure BDA0002931256580000083
respectively representing the maximum power of charging and discharging of the energy stored at the node i;
Figure BDA0002931256580000084
representing the charging and discharging power of the energy storage at the node i in the t period;
sixthly, energy storage residual capacity constraint, wherein the energy storage has certain capacity limitation, cannot be overcharged or discharged, and should meet the energy storage residual capacity constraint, namely:
Figure BDA0002931256580000085
in the formula:
Figure BDA0002931256580000086
the residual capacity of energy stored at the node i in the period t;
Figure BDA0002931256580000087
and
Figure BDA0002931256580000088
maximum and minimum capacity limits of energy storage at node i; etach、ηdisRespectively the charge and discharge efficiency of the stored energy;
and seventhly, carrying out capacitor switching constraint, wherein in order to meet reactive power requirements of loads during the operation of an island of the active power distribution network and an under-voltage problem caused by reactive power shortage after network reconstruction, a capacitor bank needs to be switched for reactive power compensation in the process of recovering the island and reconstruction faults, and the capacitor switching constraint is met, namely:
Figure BDA0002931256580000089
in the formula:
Figure BDA00029312565800000810
for the reactive compensation capacity of the capacitor at node i during the period t,
Figure BDA00029312565800000811
representing the compensation capacity put into a single capacitor,
Figure BDA00029312565800000812
the number of capacitors switched at node i for the t period,
Figure BDA00029312565800000813
the total number of capacitors available for switching at node i.
The island fusion inspection strategy is adopted to adjust and optimize the island fusion inspection strategy, and the specific operation of determining the optimal island division range in the period is as follows:
judging whether the preliminary island division range has intersection or not, and removing the island division result with the intersection to obtain an equivalent node; the removing specifically includes that when island division results corresponding to two adjacent distributed power supplies have an intersection, all nodes on a communication path between distributed power supply access nodes in an island are combined into an equivalent node, distributed power supplies in the two islands are combined into an equivalent distributed power supply, and if a branch exists on the communication path between the distributed power supply access nodes, the branch is directly connected with the equivalent node;
determining a preliminary island division range according to breadth-first search and depth-first search by taking the equivalent node as a root node, judging whether the preliminary island division range has an intersection, and removing island division results with the intersection to obtain the equivalent node; repeating the steps until all the islands have no intersection, and obtaining an optimal island division range without intersection;
fusing any two adjacent islands according to the optimal island division range, and outputting an island division result in the time period; the merging is to merge all nodes in the line between the two island ranges into the island range, if the merged island meets the constraint condition of island division, island merging operation is carried out, otherwise, island merging is cancelled, and the optimal island division range of the time period is obtained.
In an embodiment of the present invention, in an island fusion process when there is an intersection between islands, referring to fig. 3, the island results corresponding to two adjacent distributed power sources have an intersection, nodes (fig. 3, node 6 to node 11) on communication paths between distributed power source access nodes in the island results are merged into an equivalent node (fig. 3, node E), two distributed power sources (fig. 3, DG1, and DG2) are merged into an equivalent distributed power source (fig. 3, DG1+ DG2), and a branch (fig. 3, nodes 15, 16, and 17) exists on a communication path between two distributed power source access nodes, and then the branch is directly connected to the equivalent node.
In an embodiment of the present invention, when there is no intersection in the island division, the island fusion process is, referring to fig. 4, merging all nodes (fig. 4, node 5 to node 11) in the line between any two adjacent island ranges into one island range, if the island meets the constraint condition of the island division, performing island fusion operation, otherwise, canceling the island fusion.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent structures made by using the contents of the specification and the drawings of the present invention or directly or indirectly applied to other related technical fields are included in the scope of the present invention.

Claims (2)

1. A method for dynamic islanding of a power distribution network comprising a distributed power supply is characterized by comprising the following steps:
acquiring initial data, wherein the initial data comprises fault position information, planned power failure time information, power distribution network parameters during fault, load grade parameters, load power prediction and energy storage charge state in the period;
calculating the feasible solution of the island in the period, taking load nodes connected with the distributed power supply and the energy storage as root nodes according to the initial data, and determining the range of each power circle by adopting a breadth-first search algorithm on the premise of meeting related constraints to obtain the feasible solution of the island in the period;
dividing an island range, and searching a preliminary island division range of the time period corresponding to the maximum equivalent load recovery scheme by adopting a depth-first search algorithm on the premise of meeting related constraints according to the island feasible solution of the time period;
optimizing an island division range, and adjusting and optimizing the initial island division range in the period by adopting an island fusion inspection strategy according to the initial island division range in the period to determine the optimal island division range in the period;
judging whether the optimal islanding ranges of all the time periods are determined, if not, calculating the energy storage charge state of the next time period, determining the optimal islanding ranges of the next time period until the optimal islanding ranges of all the time periods are determined, bringing the optimal islanding ranges of all the time periods into a dynamic islanding scheme set, outputting the dynamic islanding scheme set, and finishing the islanding;
the specific operation of determining the range of each power circle by using the breadth-first search algorithm is as follows:
setting an array a for indicating whether the node is searched; searching all root nodes at the current moment by taking the load nodes connected with the distributed power supply and the energy storage as root nodes, and recording the root nodes as searched nodes in the array a; taking a distributed power supply and energy storage output connected with a root node as a power circle radius of the root node, and if the power circle radius is larger than the load power of the root node, taking the root node as a feasible node and recording the feasible node into a queue A;
searching all lower-layer nodes adjacent to the root node in the network, and recording the lower-layer nodes as searched nodes in the array a; if the sum of the load power of a certain lower-layer node and the load power of the node connected to the upper layer is smaller than the power circle radius of the root node to which the node belongs, recording the node as a feasible node into the queue A, otherwise, not operating the node and stopping searching the node connected to the lower layer;
starting from the lower node recorded in the queue A, searching all nodes of which the lower layer is not searched, recording the nodes of the lower layer as searched nodes in the array a, recording the nodes of the lower layer into the queue A if the sum of the load power of a certain node and the nodes connected to the upper layer is smaller than the power circle radius of the root node to which the node belongs, and otherwise, not operating the nodes and stopping searching the nodes connected to the lower layer; by analogy, searching layer by layer until all nodes in the network are searched, wherein the nodes contained in the queue A are feasible solutions of island division;
the depth-first search algorithm determines a preliminary island division range by taking the maximum equivalent load recovery quantity as a target; the objective function established with the maximum equivalent load recovery amount is as follows:
Figure FDA0003540443610000021
in the formula, Nt，LRepresenting the total number of load nodes contained in the island system at the time t; x is the number ofiTaking a value of 1 or 0 when xiWhen the number is 1, indicating that the node i participates in the islanding, otherwise, not participating in the islanding; c. CiReflecting the load weight of the node i, wherein the higher the priority level of the load is, the larger the weight is; pL,i,tThe active power loaded for the node i at the moment t;
the island fusion inspection strategy is adopted to adjust and optimize the island fusion inspection strategy, and the specific operation of determining the optimal island division range in the period is as follows:
judging whether the preliminary island division range has intersection or not, and removing the island division result with the intersection to obtain an equivalent node; the removing specifically includes that when island division results corresponding to two adjacent distributed power supplies have an intersection, all nodes on a communication path between distributed power supply access nodes in an island are combined into an equivalent node, distributed power supplies in the two islands are combined into an equivalent distributed power supply, and if a branch exists on the communication path between the distributed power supply access nodes, the branch is directly connected with the equivalent node;
determining a preliminary island division range according to breadth-first search and depth-first search by taking the equivalent node as a root node, judging whether the preliminary island division range has an intersection, and removing island division results with the intersection to obtain the equivalent node; repeating the steps until all the islands have no intersection, and obtaining an optimal island division range without intersection;
fusing any two adjacent islands according to the optimal island division range, and outputting an island division result in the time period; the merging is to merge all nodes in the line between the two island ranges into the island range, if the merged island meets the constraint condition of island division, island merging operation is carried out, otherwise, island merging is cancelled, and the optimal island division range of the time period is obtained.
2. The method for dynamic islanding of a power distribution network including distributed power supplies according to claim 1, wherein each electrical constraint condition is taken into consideration when searching for a preliminary islanding range in the current period corresponding to a maximum equivalent load recovery scheme by using a depth-first search algorithm, the constraint conditions for islanding include,
firstly, node voltage and branch current constraint:
Figure FDA0003540443610000022
in the formula: vi,tIs the voltage of node i at time t, Vi max、Vi minRespectively representing the upper limit and the lower limit of the voltage of a node i; i isij,tFor the current flowing on branch i-j during time t,
Figure FDA0003540443610000023
allowing the maximum current for branch i-j;
node power balance constraint:
Figure FDA0003540443610000031
in the formula: vi,t、Vj,tThe voltages of the nodes i and j in the period t; alpha is 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; pis,t、Qis,tRespectively injecting active power and reactive power into a node i at the moment t;Gij、Bijfor the conductance and susceptance, delta, of the branches i-jij,tThe voltage phase angle difference of the branch i-j is t time period; c (i) is a node set connected with the node i;
③ DG Power constraint:
Figure FDA0003540443610000032
in the formula: pDG,i,t、QDG,i,tActive output and reactive output of DG at a node i in a period t;
Figure FDA0003540443610000033
the upper limit of active output and reactive output of DG at a node i in the t period;
Figure FDA0003540443610000034
the lower limit of active output and reactive output of DG at a node i in the t period;
network structure constraint:
Figure FDA0003540443610000035
in the formula: f. ofdiIs the virtual load of node i, fij,tIs the virtual flow passing through the branch i-j in the period t, NbIs the number of branches, NnIs the number of nodes, NsThe number of power supplies;
energy storage charging and discharging state and power constraint:
Figure FDA0003540443610000036
in the formula:
Figure FDA0003540443610000037
respectively representing 0-1 variables of the charge and discharge state of the energy stored at the node i in the period t;
Figure FDA0003540443610000038
respectively representing the maximum power of charging and discharging of the energy stored at the node i;
Figure FDA0003540443610000039
representing the charging and discharging power of the energy storage at the node i in the t period;
sixthly, energy storage residual capacity constraint:
Figure FDA0003540443610000041
in the formula:
Figure FDA0003540443610000042
the residual capacity of energy stored at the node i in the period t;
Figure FDA0003540443610000043
and
Figure FDA0003540443610000044
maximum and minimum capacity limits of energy storage at node i; etach、ηdisRespectively the charge and discharge efficiency of the stored energy;
seventh, capacitor switching constraint:
Figure FDA0003540443610000045
in the formula:
Figure FDA0003540443610000046
for the reactive compensation capacity of the capacitor at node i during the period t,
Figure FDA0003540443610000047
representing the compensation capacity put into a single capacitor,
Figure FDA0003540443610000048
the number of capacitors switched at node i for the t period,
Figure FDA0003540443610000049
the total number of capacitors available for switching at node i.
CN202110148677.XA 2021-02-03 2021-02-03 Dynamic island division method for power distribution network comprising distributed power supply Active CN112910000B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110148677.XA CN112910000B (en) 2021-02-03 2021-02-03 Dynamic island division method for power distribution network comprising distributed power supply

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110148677.XA CN112910000B (en) 2021-02-03 2021-02-03 Dynamic island division method for power distribution network comprising distributed power supply

Publications (2)

Publication Number Publication Date
CN112910000A CN112910000A (en) 2021-06-04
CN112910000B true CN112910000B (en) 2022-05-13

Family

ID=76121875

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110148677.XA Active CN112910000B (en) 2021-02-03 2021-02-03 Dynamic island division method for power distribution network comprising distributed power supply

Country Status (1)

Country Link
CN (1) CN112910000B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113300376B (en) * 2021-06-09 2023-04-07 河北农业大学 Power distribution terminal optimal configuration method and system
CN113872237B (en) * 2021-09-18 2023-11-10 国家电网有限公司 Island division method for power distribution network
CN117081141A (en) * 2023-07-12 2023-11-17 三峡大学 Micro-grid island division method based on entropy method-set pair analysis

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2600479A1 (en) * 2011-12-02 2013-06-05 ABB Research Ltd. Controlling an electrical grid with islanded operation
CN102738834B (en) * 2012-06-21 2014-08-20 浙江大学 Method for dynamically dividing and operating multiple islands of city micro power grid with photovoltaic power supplies
CN108711882A (en) * 2018-07-19 2018-10-26 国网山东省电力公司青岛供电公司 Active distribution network isolated island division methods containing distributed generation resource and micro-capacitance sensor
CN110492526B (en) * 2019-08-29 2023-04-07 国网上海市电力公司 Island division method based on adjustable load

Also Published As

Publication number Publication date
CN112910000A (en) 2021-06-04

Similar Documents

Publication Publication Date Title
CN112910000B (en) Dynamic island division method for power distribution network comprising distributed power supply
Wong et al. Review on the optimal placement, sizing and control of an energy storage system in the distribution network
US9985438B2 (en) Optimization method for independent micro-grid system
CN109325608B (en) Distributed power supply optimal configuration method considering energy storage and considering photovoltaic randomness
CN108988322B (en) Microgrid operation strategy optimization method considering system time-varying property
Zeng et al. State-of-charge dynamic balancing strategy for distributed energy storage system in DC shipboard microgrid
CN103248064A (en) Composite energy charging energy storage system and method thereof
CN111293718B (en) AC/DC hybrid micro-grid partition two-layer optimization operation method based on scene analysis
CN111817345A (en) Reconstruction method for power distribution network with distributed power supply after serious fault
CN112909942B (en) Active power distribution network fault recovery method and system based on hybrid solving strategy
Sahoo et al. Battery state‐of‐charge‐based control and frequency regulation in the MMG system using fuzzy logic
Zhou et al. Bi-level framework for microgrid capacity planning under dynamic wireless charging of electric vehicles
CN108711882A (en) Active distribution network isolated island division methods containing distributed generation resource and micro-capacitance sensor
CN203839944U (en) Control system for smooth switching of microgrid operation modes based on DG ad-hoc network strategy
Kaysal et al. Hierarchical energy management system with multiple operation modes for hybrid DC microgrid
CN112380694A (en) Power distribution network optimization planning method based on differential reliability requirements
Han et al. Planning and overall economic evaluation of photovoltaic-energy storage station based on game theory and analytic hierarchy process
Bhardwaj et al. Sizing optimization of a stand-alone PV/Wind power supply system with hybrid energy storage
Wang et al. A hybrid transmission network in pelagic islands with submarine cables and all-electric vessel based energy transmission routes
Elkholy et al. Techno-economic configuration of a hybrid backup system within a microgrid considering vehicle-to-grid technology: A case study of a remote area
Faraji et al. Multi-level coordinated control of islanded DC microgrid integrated with electric vehicle charging stations with fault ride-through capability
CN113078633B (en) Method for improving restoring force of power transmission and distribution coupling system containing renewable energy
Krishna et al. A novel algorithm for the loss estimation and minimization of radial distribution system with distributed generation
Razzaq et al. Energy management system for AC/DC HMGS integrated with interconnected renewable sources and interlinking converter
Sun et al. Optimal operation strategy of wind-hydrogen integrated energy system based on NSGA-II algorithm

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
TA01 Transfer of patent application right
TA01 Transfer of patent application right

Effective date of registration: 20220225

Address after: 352100 NO.48 Hefeng Road, Jiaocheng District, Ningde City, Fujian Province

Applicant after: NINGDE POWER SUPPLY COMPANY, STATE GRID FUJIAN ELECTRIC POWER Co.,Ltd.

Applicant after: STATE GRID FUJIAN ECONOMIC Research Institute

Applicant after: STATE GRID FUJIAN ELECTRIC POWER Co.,Ltd.

Address before: 352100 NO.48 Hefeng Road, Jiaocheng District, Ningde City, Fujian Province

Applicant before: NINGDE POWER SUPPLY COMPANY, STATE GRID FUJIAN ELECTRIC POWER Co.,Ltd.

Applicant before: State Grid Fujian Electric Power Co., Ltd

GR01 Patent grant
GR01 Patent grant