CN-122026310-A - Active power distribution network reconstruction method and system considering multistage loop grid structure

CN122026310ACN 122026310 ACN122026310 ACN 122026310ACN-122026310-A

Abstract

The method comprises the steps of extracting all the double-ring networks and the single-ring networks in the multi-stage loop network structure, collecting data required by network reconstruction calculation, constructing a constraint condition of an active power distribution network reconstruction process by taking the minimum load balance degree among feeder lines as an optimization target and the power distribution network switching state as an optimization variable, determining an objective function of the active power distribution network reconstruction to obtain a network reconstruction model, calculating the load equivalent power of the active power distribution network, and carrying out hierarchical network reconstruction on the double-ring networks and the single-ring networks by adopting an optimizing algorithm according to the network reconstruction model and the load equivalent power of the active power distribution network to obtain an active power distribution network reconstruction scheme. Aiming at a multi-stage loop grid structure with complex topology, the invention reduces the situations of misjudgment and misexecution of a dispatcher, accurately describes the load flow distribution and the load state of the multi-stage loop distribution network, and reduces the calculation complexity by layering optimization.

Inventors

ZHANG RUIXUE
ZHANG FANBIN
ZHU KAIFU
XIONG YING
Lang Zhenchuan
HOU ZHEFAN
MA ZHIBIN
NI YONGFENG
BAO WEI

Assignees

国家电网有限公司
国网电力科学研究院有限公司
北京科东电力控制系统有限责任公司

Dates

Publication Date: 20260512
Application Date: 20251229

Claims (10)

1. The active power distribution network reconstruction method considering the multistage loop network structure is characterized by comprising the following steps of: Step 1, extracting all the double-loop networks and single-loop networks in a multi-loop network frame structure, and collecting data required by network reconstruction calculation, wherein the data comprise feeder capacity of a feeder to be analyzed, a maximum allowable current value of a line and automatic switch measurement data; Step 2, constructing constraint conditions of a power distribution network reconstruction process by taking the minimum load balance among feeder lines as an optimization target and taking the switching state of a power distribution network as an optimization variable according to the feeder line capacity of the feeder lines to be analyzed and the maximum allowable current value of the lines, and determining an objective function of the active power distribution network reconstruction to obtain a network reconstruction model; Step 3, calculating the load equivalent power of the active power distribution network by using the automatic switch measurement data; and 4, carrying out hierarchical network reconstruction on the dual-ring network and the single-ring network by adopting an optimizing algorithm according to the network reconstruction model and the load equivalent power of the active power distribution network, so as to obtain an active power distribution network reconstruction scheme.
2. The method for reconstructing an active power distribution network taking into account a multistage loop network architecture according to claim 1, wherein: In step 1, a loop of a main line in a double-loop network line is found through hierarchical loop searching, a switch in each double-loop network switching station is recorded, an outgoing line switch in each double-loop network switching station is used as a power supply point, a single loop at the downstream is analyzed, power supply points are respectively found from two sides of each disconnected contact switch at the downstream of the double-loop network switching station, a connected branch is recorded, a public branch is removed, and the rest branch is used as a loop formed by closing the contact switches.
3. The method for reconstructing an active power distribution network taking into account a multistage loop network architecture according to claim 1, wherein: in the step 1, the acquired data required by network reconstruction calculation further comprises line length, wire type and feeder line inlet switch voltage, wherein the line length and the wire type are used for carrying out power flow calculation, and the feeder line inlet switch voltage is used as the voltage of an equivalent power supply point.
4. The method for reconstructing an active power distribution network taking into account a multistage loop network architecture according to claim 1, wherein: The step 2 comprises the following steps: Step 2.1, generating an electric island by taking a bus outlet switch as a power supply and a low-voltage side of a distribution transformer as an equivalent load, setting an optimal variable of a distribution network reconstruction as a distribution network switch state, and setting an optimal target of the distribution network reconstruction as load balancing; Step 2.2, constructing constraint conditions of a power distribution network reconstruction process, wherein the constraint conditions comprise node voltage constraint and line current constraint; Step 2.3, judging whether the feeder power is positive or negative, and calculating the load balance degree between the feeders; Step 2.4, constructing an objective function of active power distribution network reconstruction according to the constraint condition of the step 2.2 and the load balance degree among the feeder lines of the step 2.3; and 2.5, constructing additional constraint conditions including network reconstruction topology constraints.
5. The method for reconstructing an active power distribution network taking into account a multistage loop network architecture according to claim 4, wherein: judging whether the feeder power is positive or negative, and calculating the load balance degree between the feeders comprises the following steps: Accumulating all load active power under all feeder lines to be optimized, calculating total active power P of a feeder line group, and then respectively calculating load balance degree among the feeder lines according to positive and negative of the sum P k of the total active power P of the feeder line group and the load active power carried by the feeder lines Expressed by the following formula: (P k <0, total active power of feeder group P is greater than or equal to 0) (P k is more than or equal to 0, and the total active power P of the feeder group is more than or equal to 0) (P k <0, total active power of feeder group P < 0) (P k is more than or equal to 0, the total active power of the feeder group P < 0) Wherein P k 、Q k is the sum of active power and reactive power carried by the feeder k, and S kmax is the maximum capacity of the feeder k.
6. The method for reconstructing an active power distribution network taking into account a multistage loop network architecture according to claim 5, wherein: adding node voltage constraint and line current constraint into an objective function through a boundary crossing penalty function, wherein the objective function of active power distribution network reconstruction is expressed by the following formula: wherein, l is the number of feeder lines to be optimized, f1 is the voltage out-of-limit penalty coefficient, f2 is the line current out-of-limit penalty coefficient, As the voltage value of the node i, For the voltage limit value of node i, For the kth line current, Is the kth line current limit.
7. The method for reconstructing an active power distribution network taking into account a multistage loop network architecture according to claim 4, wherein: The network reconfiguration topology constraint includes: the open-loop points of the two looped netowrk in the double looped netowrk are the switches of the same open-close station, each looped netowrk has one open-loop point, the condition of loop closing operation does not occur, and the incoming line switch of each looped netowrk is in a closed state and can not be operated.
8. The method for reconstructing an active power distribution network taking into account a multistage loop network architecture according to claim 1, wherein: The step 3 comprises the following steps: Step 3.1, for a switch in a power distribution station room, determining a power direction by taking a station room bus as a reference direction, and for a load at the downstream of an outgoing line switch in a ring main unit, determining the power direction according to the positive and negative values of the power of the outgoing line switch; and 3.2, taking the reference direction of the switching power outside the station room as the reference direction of the feeder bus in the static model relation, and calculating the power value of the load by subtracting the power value of the downstream switch from the upstream switch of the interval-associated automatic switch.
9. The method for reconstructing an active power distribution network taking into account a multistage loop network architecture according to claim 1, wherein: step 4 comprises: Step 4.1, converting the split result of the double loop network and the single loop network in the step 1 into chromosome coding, wherein a branch which is not contained by all loops is used as an inoperable branch, a switch connected with the inoperable branch is used as an inoperable switch, a public switch among all gene templates is recorded, only one gene template is limited to operate the public switch at the same time, genes of feeder line inlet switches are removed from the gene templates, the switch connected with the rest branch is found, and repeated switches are removed, so that a chromosome coding result is obtained, wherein a switch state is used as a gene, and a switch combination on each loop is used as a group of gene templates; step 4.2, obtaining a next generation population by using hierarchical genetic operations, wherein the hierarchical genetic operations comprise hierarchical coding and initial population generation, hierarchical selection and replication operations, hierarchical crossing operations, hierarchical mutation operations and hierarchical inversion operations; Step 4.3, calculating chromosome adaptation values of each generation of population; And 4.4, selecting an optimal solution as a final active power distribution network reconstruction scheme, and outputting a power flow comparison result before and after reconstruction, node voltage out-of-limit times before and after reconstruction, line current out-of-limit times before and after reconstruction and load balance degree change.
10. An active power distribution network reconstruction system taking into account a multi-stage loop grid structure, operating the active power distribution network reconstruction method taking into account a multi-stage loop grid structure as set forth in any one of claims 1-9, comprising: The loop analysis module is used for extracting all the double-loop networks and the single-loop networks in the multi-stage loop network frame structure and collecting data required by network reconstruction calculation; the model construction module is used for constructing constraint conditions in a power distribution network reconstruction process by taking the minimum load balance degree among feeder lines as an optimization target and taking the switching state of the power distribution network as an optimization variable, and determining an objective function of the active power distribution network reconstruction to obtain a network reconstruction model; the load calculation module is used for calculating the load equivalent power of the active power distribution network; and the model optimizing module is used for carrying out hierarchical network reconstruction on the double-ring network and the single-ring network by adopting an optimizing algorithm according to the network reconstruction model and the load equivalent power of the active power distribution network, so as to obtain an active power distribution network reconstruction scheme.

Description

Active power distribution network reconstruction method and system considering multistage loop grid structure Technical Field The invention belongs to the technical field of distribution network optimization, and particularly relates to an active power distribution network reconstruction method and system considering a multistage loop network frame structure. Background With the increasing of distribution network scale and increasing of town level, the grid structure of the current distribution network is more and more complex, the power supply reliability provided by a single radiation line, a multi-section single-contact line and a multi-section moderate contact line in the urban distribution network with more and more dense load distribution can not meet the requirement, and the construction of the complex grid structure of a double-ring network line, a double-petal line and the like which can meet the N-2 safety criterion can provide higher power supply reliability. Meanwhile, a distributed power supply (including photovoltaic, wind power, energy storage and the like) is connected into the power distribution network in a large scale, so that an active power distribution network system consisting of the distributed power supply, a load, an energy storage system and a control device is formed, and bidirectional power flow is realized. With the continuous development of complex grid structures and active power distribution networks, the problem of unbalanced feeder load and power distribution is accompanied, and a scheduler is difficult to control increasingly complex power distribution network systems, so that a new analysis method for reconstructing an active power distribution network with a multistage complex loop grid structure is needed to reduce the analysis amount of scheduling staff. The network reconstruction of the power distribution network is an optimization method for eliminating branch overload and voltage out-of-limit, balancing feeder load and power supply and reducing line loss by changing the operation mode of a power distribution line through switch operation on the premise of meeting safety constraint. At present, some technical researches are carried out on the reconstruction of a power distribution network without considering the direction of power flow, and the method is mainly used on lines of a simple grid structure of a multi-section single-contact line and a multi-section moderate-contact line, and aims to reduce the line loss of the power distribution network, balance the load, eliminate overload and improve the quality of power supply voltage. After the topological structure of the power grid model is generated, analysis is carried out through a mathematical optimization theory algorithm, an optimal flow mode algorithm, a branch exchange algorithm or an artificial intelligent algorithm, and an information function scheduling operator such as a switching operation optimization scheme, network loss change before and after optimization and power flow change and the like is generated for analysis operation. Prior art document 1 (CN 120810622 a) discloses a distributed photovoltaic digestion capability enhancing method and system based on network reconstruction. The disadvantage of the prior art document 1 is that the key topological constraint in the actual engineering is not involved, the optimization target is not distinguished, the load flow direction is only used as a criterion by taking the average load rate deviation of all feeder lines, and the reconstruction calculation requirement of the active power distribution network of the multistage ring network grid structure cannot be met. Disclosure of Invention In order to solve the defects in the prior art, the invention provides an active power distribution network reconstruction method and system considering a multistage loop network frame structure, which assist a dispatcher in solving the problems of feeder load and power balance under a complex network frame structure. The invention adopts the following technical scheme. The first aspect of the invention provides an active power distribution network reconstruction method considering a multistage loop grid structure, which comprises the following steps: Step 1, extracting all the double-loop networks and single-loop networks in a multi-loop network frame structure, and collecting data required by network reconstruction calculation, wherein the data comprise feeder capacity of a feeder to be analyzed, a maximum allowable current value of a line and automatic switch measurement data; Step 2, constructing constraint conditions of a power distribution network reconstruction process by taking the minimum load balance among feeder lines as an optimization target and taking the switching state of a power distribution network as an optimization variable according to the feeder line capacity of the feeder lines to be analyzed and the maximum allowable current value of the lines, and