WO2015196743A1

WO2015196743A1 - Active distribution network reconfiguration method and apparatus

Info

Publication number: WO2015196743A1
Application number: PCT/CN2014/093191
Authority: WO
Inventors: 舒彬; 韩晓鹏; 张凯; 刘兆燕; 李雪男; 吴振升
Original assignee: 国家电网公司; 国网北京市电力公司; 北京电力经济技术研究院; 中电高科（北京）科技有限公司; 华北电力大学
Priority date: 2014-06-25
Filing date: 2014-12-05
Publication date: 2015-12-30
Also published as: CN105225163A

Abstract

The present invention discloses an active distribution network reconfiguration method and apparatus. The active distribution network reconfiguration method comprises: a target function of a minimum power generation charge is obtained; calculations are performed according to the target function of the minimum power generation charge to obtain a first electricity purchase scheme; in the first electricity purchase scheme, a main grid power and a first distributed supply power are obtained; a target function of a minimum grid loss charge is obtained; the first main grid power and first distributed supply power are substituted into the target function of the minimum grid loss charge, and a first topology is calculated and obtained; it is determined whether the sum of the power generation charge under the first electricity purchase scheme and the grid loss charge under the first topology satisfies a preset condition; if the preset condition is satisfied, then the first electricity purchase scheme and the first topology serve as the reconfiguration scheme of the active distribution network. The present invention solves the problem of it being impossible to give consideration to both the electricity purchase charge and the active distribution network topology when performing active distribution network reconfiguration.

Description

Active distribution network reconfiguration method and device

Technical field

The present invention relates to the field of distribution networks, and in particular to a method and apparatus for reconstructing an active distribution network.

Background technique

In the active distribution network, there are a large number of distributed power sources, such as gas turbines, photovoltaic power generation, and wind power generation. The distribution network arranges the power generation plan. Under the current network structure, it satisfies the power balance constraint, the branch overload constraint, etc., with the goal of minimizing the purchase cost, and reasonably arranging the share of the main network purchase and the distributed power purchase. Distribution network reconfiguration is to find the network topology with the smallest network loss. Both are to get the best economic indicators, that is, the sum of the electricity purchase cost and the network loss cost is the lowest. The purchase cost and the network loss cost are mutually influential. The output of distributed power generation in the power purchase scheme affects the distribution network reconstruction; the network topology structure after the network reconstruction has affected the network loss, which in turn affects the power purchase plan.

Active distribution network technology can solve large-scale intermittent renewable energy in power grid applications, improve green energy utilization, and optimize primary energy structure. The active distribution network is a distribution network with the ability to combine and control various distributed power sources, controllable loads, energy storage, and demand side management. Its purpose is to increase the capacity of the distribution network for renewable energy, improve the utilization of distribution network assets, delay the upgrade investment of the distribution network, and improve the user's power quality and power supply reliability.

Renewable energy and clean fossil energy are increasingly distributed in active distribution networks in the form of distributed generation. The distribution network plans to fully consider the purchase power of the distributed power supply and the purchase ratio of the main network, so that the total purchase cost is the least. At the same time, the measurement, control and information transmission of the active distribution network provide conditions for the realization of the distribution network reconstruction. Distribution network reconfiguration is also a part of the active distribution network economic operation. In the prior art, when the active distribution network is reconstructed, the problem of the cost of purchasing electricity and the topology of the active distribution network cannot be considered.

In view of the problem of the power purchase cost and the topology of the active distribution network in the prior art when the active distribution network is reconstructed, an effective solution has not been proposed yet.

Summary of the invention

The main object of the present invention is to provide a method and a device for reconstructing an active distribution network, so as to solve the problem that the power purchase cost and the topology of the active distribution network cannot be taken into account when performing active distribution network reconstruction.

In order to achieve the above object, according to an aspect of the present invention, a method of reconstructing an active distribution network is provided. The method for reconstructing an active distribution network according to the present invention includes: obtaining an objective function of a minimum power generation cost; performing calculation according to an objective function of the minimum power generation cost to obtain a first power purchase plan; and in the first power purchase plan Obtaining a first primary network power and a first distributed power; obtaining an objective function of a minimum network loss cost; and substituting the first primary network power and the first distributed power into the minimum network loss cost An objective function, calculating a first topology; determining whether a sum of a power generation cost under the first power purchase plan and a network loss cost under the first topology satisfies a preset condition; and if a preset condition is met And the first power purchasing scheme and the first topology are used as a reconstruction scheme of the active power distribution network.

Further, before determining whether the sum of the power generation cost under the first power purchase plan and the network loss cost under the first topology meets a preset condition, the method further includes: at the first Under the topology, the calculation is performed according to the objective function of the minimum power generation cost to obtain a second power purchase plan; the second main network power and the second distributed power source when the second power purchase plan is acquired; The second main network power and the second distributed power supply are substituted into the objective function of the minimum network loss cost to obtain a second topology; determining the power generation cost under the second power purchase scheme and the second Whether the difference between the sum of the network loss costs of the topology and the sum of the power generation cost under the first power purchase plan and the network loss cost of the first topology meets a preset accuracy value; if the preset accuracy is met a value, the second power purchase scheme and the second topology are used as a reconstruction scheme of the active distribution network; and if the preset accuracy value is not met, under the second topology Continue to be based on The minimum cost of power purchase program to calculate the objective function.

Further, the objective function of the minimum power generation cost is

Where f ₁ is the cost of power generation, c _sysV is the price of electricity purchased from the grid in a single period, p _sys is the actual active power purchased from the grid in a single period, n is the number of nodes in the distribution network, and c _DGVi is distributed on the i-node. The price of the power source, p _DGi is the power _generated by the distributed power source at the i-node.

Further, the active power of the single-segment power purchase from the power grid follows the following constraints: p _sys ≤ p _sysmax ,

Among them, p _sys is the actual active power purchased from the main network in a single period, and p _sysmax is the maximum active power purchased from the main network in a single period.

Further, the power generation power of the distributed power source on the i-node follows the following constraint: p _DGi ≤ p _DGimax ,

Where p _DGi is the actual power generated by the distributed power source on the i-node in a single period, and the rated power of the distributed power source on the i-node of P _DGimax .

Further, the objective function of the minimum network loss cost is:

Where f ₂ is the network loss, b is the number of branches, k _j is the state variable of switch j, is 0 to 1 discrete, 0 is open, 1 is closed, r _j is the resistance of branch j, P _lj , Q _lj is the active power and reactive power flowing through the j-end of the branch, and U _j is the node voltage at the end of the branch j.

Further, the method further includes obtaining the calculated active power and the reactive power by:

Wherein, P _{_i,} Q _i to node i are injection of active power, reactive power; U _i, U _j are nodes i, j of the voltage; Gi _{_j,} Bi _j and [Delta] I _j are nodes i, j conductance, Susceptance and phase angle difference

Further, the voltage of the node i follows the following constraint condition: U _imin ≤ U _i ≤ U _imax

Where U _imax and U _imin are the upper and lower limits of the effective value of the node i voltage, respectively.

Further, the power of the branch satisfies the following constraint condition: S _j ≤S _jmax ,

Where S _j is the actual flow power of the j-th branch; S _jmax is the maximum transmission power of the j-th branch.

In order to achieve the above object, according to another aspect of the present invention, an apparatus for reconfiguring an active distribution network is provided. The apparatus for reconfiguring an active distribution network according to the present invention includes: a first acquisition unit for acquiring an objective function of a minimum power generation cost; and a first calculation unit configured to perform calculation according to an objective function of the minimum power generation cost a power purchasing solution, the second acquiring unit, configured to acquire the first main network power and the first distributed power source during the first power purchasing scheme, and the third acquiring unit, configured to acquire the minimum network loss cost target a second computing unit, configured to substitute the first primary network power and the first distributed power supply into an objective function of the minimum network loss cost, to obtain a first topology structure; and a determining unit, configured to: Determining whether a sum of a power generation cost under the first power purchase scheme and a network loss fee under the first topology satisfies a preset condition; and determining a unit, when the preset condition is met, The first power purchasing scheme and the first topology are used as a reconstruction scheme of the active power distribution network.

According to the present invention, the objective function of obtaining the minimum power generation cost is adopted; the calculation is performed according to the objective function of the minimum power generation cost, and the first power purchase plan is obtained; in the first power purchase plan, the first main network power and the first distributed power source are acquired. Power; the objective function of obtaining the minimum network loss cost; the first main network power and the first distributed power source are substituted into the objective function of the minimum network loss cost, and the first topology is calculated; the judgment is made under the first power purchase plan Whether the sum of the power generation cost and the network loss cost under the first topology satisfies a preset condition; and if the preset condition is met, the first power purchase plan and the first topology are used as a reconstruction scheme of the active distribution network, It solves the problem that when the active distribution network is reconstructed, the cost of purchasing electricity and the topology of the active distribution network cannot be taken into account, and the cost of purchasing electricity and the active distribution network are realized in the reconstruction of the active distribution network. The effect of the topology.

DRAWINGS

The accompanying drawings, which are incorporated in the claims In the drawing:

1 is a flow chart of a method for reconstructing an active distribution network according to an embodiment of the present invention;

2 is a bi-level plan view in accordance with an embodiment of the present invention;

3 is a flow chart of a method of reconstructing an active distribution network in accordance with a preferred embodiment of the present invention;

4 is a schematic diagram of a reconfiguration apparatus of an active distribution network in accordance with an embodiment of the present invention.

Detailed ways

It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. The invention will be described in detail below with reference to the drawings in conjunction with the embodiments.

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is an embodiment of the invention, but not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of the present invention.

It is to be understood that the terms "first", "second" and the like in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a particular order or order. It is to be understood that the data so used may be interchanged where appropriate, so that the embodiments of the invention described herein can be implemented in a sequence other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variants thereof are intended to cover a non-exclusive inclusion, for example, a process that includes a series of steps or units. The method, system, product, or device is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not explicitly listed or are inherent to such processes, methods, products, or devices.

Embodiments of the present invention provide a method for reconstructing an active distribution network.

1 is a flow chart of a method of reconstructing an active distribution network in accordance with an embodiment of the present invention. As shown in the figure, the method for reconstructing the active distribution network includes the following steps:

Step S102, obtaining an objective function of a minimum power generation cost.

Step S104, performing calculation according to the objective function of the minimum power generation cost, to obtain a first power purchase plan.

Step S106: Acquire the first primary network power and the first distributed power supply power during the first power purchase plan.

Step S108, obtaining an objective function of the minimum network loss cost.

Step S110, the first main network power and the first distributed power supply are substituted into an objective function of the minimum network loss cost, and the first topology is calculated.

Step S112, determining whether the sum of the power generation cost under the first power purchase plan and the network loss cost under the first topology structure meets a preset condition.

Step S114, if the preset condition is met, the first power purchasing scheme and the first topology are used as a reconstruction scheme of the active distribution network.

According to the objective function of the minimum power generation cost, the power purchase plan when the power generation cost is minimum is calculated. Since the active distribution network includes the main network power generation and the distributed power supply, when the minimum power purchase scheme is obtained, the primary network power and the distributed power supply of the active distribution network can be determined, that is, the first primary network power and the first distribution. Power supply.

Then, according to the objective function of the minimum network loss cost, the first main network power and the second distributed power source are substituted into the objective function of the minimum network loss cost, and the topology structure of the active distribution network when the network loss is minimum is calculated. That is the first topology.

Then, whether the pre-set condition is satisfied after the purchase cost of the first power purchase plan and the network loss cost of the first topology is used, and if the preset condition is met, the first power purchase plan and the first topology are used as Active distribution network reconfiguration solution.

The first power purchase plan and the first topology are calculated by the objective function of the minimum power generation cost objective function and the minimum network loss cost. Since the first topology structure is calculated in the case of the first power purchase plan, the calculation is performed. The topology also takes into account the cost of purchasing electricity. Therefore, the final reconstruction plan takes into account the cost of electricity purchase and the cost of network loss, and obtains the optimal reconstruction scheme of the active distribution network, which not only solves the problem of active distribution network. When refactoring, it is impossible to balance the cost of purchasing electricity and the topology of the active distribution network, and it can also reduce the cost of active distribution network reconstruction.

Preferably, in order to determine the topology structure more accurately, not only the power purchase cost and the network loss cost are minimized, but also the active distribution network can be operated under the optimal scheme, and the power generation cost under the first power purchase scheme is judged. Before the sum of the network loss charges under the first topology meets the preset condition, the method further includes:

Under the first topology, the calculation is again performed according to the objective function of the minimum power generation cost to obtain a second power purchase plan.

Obtaining the second primary network power and the second distributed power supply when the second power purchase plan is obtained.

A second topology is obtained by substituting the second primary network power and the second distributed power to the objective function of the minimum network loss cost.

Determining whether the difference between the power generation cost under the second power purchase plan and the network loss cost in the second topology and the sum of the power generation cost under the first power purchase plan and the network loss cost in the first topology structure satisfies Set the precision value.

If the preset accuracy value is met, the second power purchase scheme and the second topology are used as a reconstruction scheme of the active distribution network.

If the preset accuracy value is not met, then under the second topology, the power purchase plan is continued to be calculated based on the objective function of the minimum power generation cost.

Under the first topology, the second power purchase scheme is obtained again according to the objective function of the minimum power generation cost. Obtaining the primary network power and the distributed power of the active distribution network in the case of the second power purchase scheme, that is, the second primary network power and the second distributed power.

The second primary network power and the second distributed power supply are then substituted into the objective function of the minimum network loss cost to calculate the second topology.

The second power purchase scheme is determined by the first topology, and the second topology structure is obtained by the second power purchase scheme, so that the power purchase scheme and the topology structure are mutually verified, and therefore, the power purchase cost and the first power purchase scheme The difference between the sum of the network loss costs of a topology structure and the sum of the power purchase cost of the second power purchase plan and the network loss of the second topology structure determines whether the difference satisfies the preset accuracy value, and if the accuracy value is satisfied And determining the second power purchasing scheme and the second topology as the reconstruction scheme of the active power distribution network. If the accuracy value is not met, the power purchase may be recalculated according to the objective function of the minimum power generation cost in the second topology. Program.

2 is a bi-level plan diagram in accordance with an embodiment of the present invention. If shown, the first layer passes the optimal power flow to obtain distributed power and mains power. The two variables are passed to the second layer plan, and the genetic algorithm is used to reconstruct the distribution network to obtain the distribution network topology under the minimum network loss. Under this structure, the network loss ratio is changed, causing the power of the main network to change, and the power purchase plan of the first layer is no longer optimal. This structure may cause the original power purchase plan to be overloaded on some branches. Therefore, the network topology of the second layer calculation result is transmitted to the first layer, and the optimal power flow calculation is performed again.

Preferably, the objective function of the minimum power generation cost is

Where f ₁ is the cost of power generation, c _sysV is the price of electricity purchased from the grid in a single period, p _sys is the actual active power purchased from the grid in a single period, n is the number of nodes in the distribution network, and c _DGVi is distributed on the i-node. The price of the power source, p _DGi is the actual power generated by the distributed power source at the i-node.

Using the electricity price purchased from the grid and the active power purchased from the grid to determine the main network purchase cost, using the distributed power source and the distributed power generation power to determine the power generation cost of the distributed power source, the purchase of electricity costs and distributed power The minimum cost of power generation is used as the cost of electricity purchase under the first power purchase plan. After the minimum purchase cost is determined, the active power of the purchased electricity and the active power of the generated electricity can be determined. The sum of the cost of purchasing electricity from the main network and the power generation cost of the distributed power source is the minimum power generation cost.

Preferably, in order to avoid the power overload of the active distribution network caused by excessive active power purchased from the main network, the active power purchased from the grid in a single period of time complies with the following constraints:

p _sys ≤p _sysmax ,

That is, the actual active power purchased from the main network in a single period is less than or equal to the maximum active power purchased from the main network in a single period.

Preferably, the power generated by the distributed power source on the i-node follows the following constraints:

p _DGi ≤p _DGimax ,

That is, the actual power generation of the distributed power source on the i-node in a single time period is less than or equal to the rated power of the distributed power source.

Under the constraint of the above two constraints, the minimum power generation cost is calculated by the objective function of the minimum power generation cost, and the power purchase power of the active distribution network from the main network and the power generation of the distributed power source are determined when the minimum power generation cost is obtained. .

That is, under the current topology, the internal point method is used to calculate the power flow, and the power balance constraint, the node voltage constraint, the branch power constraint, and the power supply power constraint are satisfied, and the power purchased from the main network and the power generated by the distributed power source are obtained.

Preferably, in order to minimize the network loss of the active distribution network, the minimum network loss is determined by the objective function of the minimum network loss cost:

Calculate the network loss of each branch in the active distribution network to determine the network loss cost of the entire active distribution network. When the switch is closed, the branch has a network loss. When the switch is opened, the branch has no network loss.

Preferably, the calculated active power and reactive power are obtained by:

Among them, P _i and Q _i respectively inject active power and reactive power into the node i. U _i and U _j are the voltages of nodes i and j, respectively. G _ij , B _ij and δ _ij are the conductance, susceptance and phase angle difference of nodes i and j, respectively

Based on the purchased power and the power generation of the distributed power source, the genetic algorithm is used to reconstruct the network, and the power balance constraint, node voltage constraint and branch power constraint are satisfied, and the network topology with the smallest network loss is obtained.

Preferably, the voltage of node i follows the following constraints:

U _imin ≤ U _i ≤ U _imax

Where U _imax and U _imin are the upper and lower limits of the effective value of the node i voltage, respectively. That is, the voltage of the node i is greater than or equal to the lower limit of the voltage effective value of the node i, and is less than or equal to the upper limit of the voltage effective value of the node i.

Preferably, the power of the branch satisfies the following constraint condition: S _j ≤ S _jmax , where S _j is the actual flow of power of the j-th branch. S _jmax is the maximum transmission power of the j-th branch.

That is, the actual flow power of the branch is less than or equal to the maximum value of the transmission power of the branch to ensure that the branch is not overloaded.

Hereinafter, a method for reconstructing an active distribution network according to a preferred embodiment of the present invention will be described with reference to FIG.

As shown in the figure, the optimal power flow calculates the power purchase cost of the active distribution network from the main network and the power generation cost of the distributed power supply. The known data required for calculation are: (1) node class: node type (load node) , generator node, distributed power node), active power and reactive power; (2) branch type: end node number, branch type (transformer, line) impedance, admittance, ratio; (3) economy Class: main network power generation cost curve, power generation cost curve of distributed power supply; (4) Constraint conditions: power balance constraint, node voltage constraint, branch power constraint, power supply power constraint; (5) calculation control variable: accuracy of iterative calculation The number of iterations, the number of populations in the genetic algorithm, the number of genetic iterations, the crossover and the probability of mutation.

Under the current topology, the internal point method is used to calculate the power flow, which satisfies the power balance constraint, the node voltage constraint, the branch power, and the power supply constraints. The power purchased from the main network and the power generated by the distributed power are obtained. Node injection power. The node injection power is substituted into the objective function of the distribution network reconstruction to obtain the network loss cost. The power generation cost is calculated by the optimal power flow calculation. The difference between the power generation cost and the network loss cost calculated by two adjacent iterations is obtained by two iterations, and it is judged whether the difference satisfies the accuracy requirement, and when the accuracy requirement is met, the calculation is ended, and when the accuracy requirement is not met, the continuation is continued. The optimal power flow calculation is performed, that is, the power generation cost of the active distribution network is calculated.

The embodiment of the invention takes into consideration the comprehensive optimal solution of the electricity purchase fee and the network loss fee. Establish a two-layer planning model, jointly optimize the power generation cost and network loss of the active distribution network. Apply the two-layer programming theory: the first layer planning, establish the optimal power flow model with the minimum purchase cost as the target, and solve the model with the interior point method. The power purchase strategy, the power purchase power under the power purchase strategy and the power generation power of the distributed power source are transmitted to the second layer plan; the second layer plan, the distribution network reconstruction model is established with the minimum network loss as the target, and the genetic algorithm is used to solve this problem. The model obtains the network topology, passes the network topology to the first-level planning model, re-purchases the power strategy, solves it through multiple iterations, and finally ends the iterative calculation when the preset accuracy is met, and obtains the power purchase plan and network topology structure. The cost of the active distribution network is balanced with the power generated.

The embodiment of the invention also provides a reconstruction device for an active distribution network.

The method for reconfiguring the active distribution network in the embodiment of the present invention can be performed by the reconfiguration device of the active distribution network provided by the embodiment of the present invention. The reconfiguration device of the active distribution network in the embodiment of the present invention can also be used. A method for reconstructing an active distribution network provided by an embodiment of the present invention is performed.

4 is a schematic diagram of a reconfiguration apparatus of an active distribution network in accordance with an embodiment of the present invention. As shown, the reconfiguration device of the active distribution network includes

The first acquisition unit 10 is configured to acquire an objective function of a minimum power generation cost.

The first calculating unit 20 is configured to perform calculation according to an objective function of the minimum power generation cost to obtain a first power purchasing plan.

The second obtaining unit 30 is configured to acquire the first primary network power and the first distributed power supply when the first power purchasing solution is used.

The third obtaining unit 40 is configured to acquire an objective function of the minimum network loss cost.

The second calculating unit 50 is configured to substitute the first primary network power and the first distributed power to the objective function of the minimum network loss cost, and calculate the first topology.

The determining unit 60 is configured to determine whether the sum of the power generation cost under the first power purchase plan and the network loss fee under the first topology structure meets a preset condition.

The determining unit 70 is configured to use the first power purchasing scheme and the first topology as a reconstruction scheme of the active distribution network when the preset condition is met.

The first power purchase plan and the first topology structure are calculated by the objective function of the minimum power generation cost objective function and the minimum network loss cost, since the first topology structure is calculated in the case of the first power purchase plan, in the calculation topology The structure also takes into account the cost of purchasing electricity. Therefore, the final reconstruction plan takes into account the cost of electricity purchase and the cost of network loss, and obtains the optimal reconstruction scheme of the active distribution network.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

An active distribution network reconfiguration method, comprising:

Obtain an objective function of the minimum power generation cost;

Calculating according to the objective function of the minimum power generation cost, to obtain a first power purchase plan;

Obtaining the first primary network power and the first distributed power supply power during the first power purchase plan;

Obtain the objective function of the minimum network loss cost;

Substituting the first primary network power and the first distributed power supply into an objective function of the minimum network loss cost, and calculating a first topology;

Determining whether a sum of a power generation cost under the first power purchase plan and a network loss cost under the first topology structure satisfies a preset condition;

If the preset condition is met, the first power purchasing scheme and the first topology are used as a reconstruction scheme of the active power distribution network.
The method according to claim 1, wherein before determining whether the sum of the power generation cost under the first power purchase plan and the network loss cost under the first topology structure satisfies a preset condition, The method also includes:

Under the first topology, calculating again according to the objective function of the minimum power generation cost, to obtain a second power purchase plan;

Obtaining a second primary network power and a second distributed power supply when the second power purchasing solution is obtained;

Substituting the second primary network power and the second distributed power supply into an objective function of the minimum network loss cost to obtain a second topology;

Determining a sum of a power generation cost under the second power purchase plan and a network loss cost in the second topology and a power generation cost under the first power purchase plan and a network loss in the first topology Whether the difference in the sum of the fees satisfies the preset accuracy value;

If the preset accuracy value is met, the second power purchasing scheme and the second topology are used as a reconstruction scheme of the active distribution network;

If the preset accuracy value is not satisfied, then under the second topology, the power purchase scheme is continued to be calculated according to the objective function of the minimum power generation cost.
The method of claim 1 wherein said objective function of said minimum power generation cost is

Where f 1 is the cost of power generation, c sysV is the price of electricity purchased from the grid in a single period, p sys is the actual active power purchased from the grid in a single period, n is the number of nodes in the distribution network, and c DGVi is distributed on the i-node. The price of the power source, p DGi is the power generated by the distributed power source at the i-node.
The method according to claim 3, wherein the active power purchased from the grid in a single period of time follows the following constraints:

p sys ≤p sysmax ,

Among them, p sys is the actual active power purchased from the main network in a single period, and p sysmax is the maximum active power purchased from the main network in a single period.
The method of claim 3 wherein the power generation of the distributed power source at the i-node follows the following constraints:

p DGi ≤p DGimax ,

Where p DGi is the actual power generated by the distributed power source on the i-node in a single period, and the rated power of the distributed power source on the i-node of P DGimax .
The method of claim 1 wherein the objective function of the minimum network loss cost is:

Where f 2 is the network loss, b is the number of branches, k j is the state variable of switch j, is 0 to 1 discrete, 0 is open, 1 is closed, r j is the resistance of branch j, P lj , Q lj is the active power and reactive power flowing through the j-end of the branch, and U j is the node voltage at the end of the branch j.
The method according to claim 6, wherein the method further comprises: calculating the active power and the reactive power by:

Wherein, P i and Q i respectively inject active power and reactive power into node i; U i and U j are voltages of nodes i and j, respectively; G ij , B ij and δ ij are conductances of nodes i and j, respectively. Susceptance and phase angle difference
The method of claim 7 wherein the voltage of the node i follows the following constraints:

U imin ≤ U i ≤ U imax

Where U imax and U imin are the upper and lower limits of the effective value of the node i voltage, respectively.
The method of claim 6 wherein the power of the branch satisfies the following constraints:

S j ≤S jmax ,

Where S j is the actual flow power of the j-th branch; S jmax is the maximum transmission power of the j-th branch.
An apparatus for reconfiguring an active distribution network, comprising:

a first obtaining unit, configured to acquire an objective function of a minimum power generation cost;

a first calculating unit, configured to perform calculation according to an objective function of the minimum power generation cost, to obtain a first power purchasing plan;

a second acquiring unit, configured to acquire, when the first power purchasing solution, the first primary network power and the first distributed power supply;

a third obtaining unit, configured to acquire an objective function of a minimum network loss fee;

a second calculating unit, configured to substitute the first primary network power and the first distributed power supply into an objective function of the minimum network loss cost, to calculate a first topology;

a determining unit, configured to determine whether a sum of a power generation cost under the first power purchase plan and a network loss fee under the first topology structure meets a preset condition;

And a determining unit, configured to use the first power purchasing scheme and the first topology as a reconstruction scheme of the active distribution network when a preset condition is met.