Optimal configuration method for reactive power compensation equipment of transformer substation with collaborative energy storage value

Abstract

The invention discloses a transformer substation reactive power compensation equipment optimal configuration method cooperating with energy storage value, electronic equipment and a medium, and the method comprises the following steps: depicting the physical characteristics of an energy storage compensator and a reactive power compensator based on a Distflow equation; dividing power flow in the power distribution network considering factors including the type, the quantity, the output power, the access mode and the load of new energy power generation so as to coordinate active power and reactive power; based on the power flow, constructing a target function taking the minimization of the voltage deviation value and the load shedding cost as targets; and according to a preset photovoltaic energy storage capacity constraint, an energy storage charging and discharging constraint, a power flow constraint, a power distribution network branch current constraint, a power distribution network node voltage constraint, a second-order cone constraint and a target function, carrying out collaborative optimization of the energy storage and reactive power compensation device.

Description

Technical Field

[0001] The present invention relates to the field of electrical engineering technology, and in particular to a method for optimizing configuration of reactive power compensation equipment in a transformer substation with coordinated energy storage value, electronic equipment, and a medium. Background Art

[0002] With the development of energy storage system (ESS) technology and the reduction of construction costs, ESS is one of the potential key technologies applied to distribution network operations. The most common operation strategy of ESS is to store the power generation as load during the valley period with small load, and generate power during the peak period with large load. Through this "high storage and low generation" approach, ESS is widely used to shave peaks and fill valleys and reduce the power cost of distribution networks. In addition, ESS can improve voltage stability and active power balancing capabilities by utilizing its flexible operation capabilities to compensate for the uncertainty in the output power of renewable energy generation.

[0003] However, the active power, reactive power and node voltage in the distribution network are coupled with each other, which increases the difficulty of optimizing the coordination strategy. It needs to consider the coordination of the distributed network. Although some studies have explored the planning of distribution networks with energy storage in different scenarios, considering the type, quantity, output power, access method, load conditions of substations and other factors of renewable energy generation, the flexibility of the power system is greatly affected and the risk of load shedding in certain scenarios is reduced. Voltage deviation will limit the effectiveness of energy transfer provided by energy storage. Therefore, the coordinated control of active and reactive power in the distribution network plays an important role in the operation of the distribution network. Summary of the invention

[0004] The purpose of the present invention is to provide a method, electronic equipment and medium for optimizing configuration of reactive power compensation equipment in a substation with coordinated energy storage value in view of the problems existing in the prior art.

[0005] In a first aspect, an embodiment of the present invention provides a method for optimizing configuration of reactive power compensation equipment in a substation in coordination with energy storage value, the method comprising the following steps:

[0006] Based on the Distflow equation, the physical characteristics of energy storage and reactive compensator are characterized, and the power flow is divided in the distribution network considering factors including the type, quantity, output power, access mode and load of renewable energy generation to coordinate active power and reactive power;

[0007] Based on the power flow, an objective function is constructed with the goal of minimizing the voltage deviation and load shedding cost. The energy storage and reactive compensation devices are collaboratively optimized according to the preset photovoltaic energy storage capacity constraints, energy storage charging and discharging constraints, flow constraints, distribution network branch current constraints, distribution network node voltage constraints, second-order cone constraints and objective functions.

[0008] In a second aspect, an embodiment of the present invention provides an electronic device, comprising a memory and a processor, wherein the memory is coupled to the processor; wherein the memory is used to store program data, and the processor is used to execute the program data to realize the above-mentioned method for optimizing the configuration of reactive compensation equipment of a substation with collaborative energy storage value.

[0009] In a third aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for optimizing configuration of reactive compensation equipment in a substation with collaborative energy storage value.

[0010] In a fourth aspect, an embodiment of the present invention provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the above-mentioned method for optimizing the configuration of reactive compensation equipment in a substation with collaborative energy storage value.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. Adopt a multi-objective optimization configuration method for distribution networks including energy storage and reactive power compensation devices, consider the capacity and site selection of new energy access, load changes and other factors, and make reasonable configuration decisions to coordinate active power and reactive power;

[0013] 2. Taking into account the random fluctuations of wind and solar power output, the advantages of random optimization and robust optimization are combined, and typical scenarios of renewable energy output (wind and solar power) and extreme scenarios of load growth are selected for optimization, which improves the calculation efficiency of the solution. In addition, the voltage stability of the distribution network is considered, which is suitable for the configuration and application of reactive power compensation devices in the distribution network and is reasonable.

[0014] 3. As the penetration rate of wind and solar power increases, the system improves its reactive power compensation capability by configuring energy storage and reactive power compensators, while taking into account the voltage deviation of distribution network nodes and load shedding cost indicators for optimization, which not only reduces the operating cost of the system, but also ensures safe and stable operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0016] Figure 1 A flow chart of a method for optimizing configuration of reactive power compensation equipment in a substation with coordinated energy storage value provided by an embodiment of the present invention;

[0017] Figure 2 A schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that, in the absence of conflict, the features in the following embodiments and implementations may be combined with each other. Figure 1 As shown, the present invention provides a method for optimizing configuration of reactive power compensation equipment in a substation with coordinated energy storage value, the method comprising the following steps:

[0020] Step S1, characterizes the physical characteristics of energy storage and reactive power compensator based on Distflow equation, and divides the power flow in the distribution network considering factors including the type, quantity, output power, access mode and load of renewable energy generation to coordinate active power and reactive power.

[0021] Specifically, the step S1 includes:

[0022] Among them, the physical characteristics of energy storage are described as follows:

[0023]

[0024]

[0025] In the formula, is the energy storage discharge power at node j at time t, is the maximum energy storage discharge power at node j at time t, is the energy storage charging power at node j at time t, is the energy storage charging power at node j at time t, is the maximum energy storage discharge energy at node j at time t, is the energy storage discharge energy at node j at time t, u dch is the energy storage discharge state, u ch SOC is the energy storage charging state. ess,min , SOC ess,max is the minimum and maximum value of energy storage capacity, SOC ess (t) is the capacity of energy storage at time t.

[0026] Among them, the reactive power compensation device mainly considers the optimized operation of capacitor bank (CB) and static VAR generator (SVG). The operating characteristics of CB and SVG can be expressed as:

[0027]

[0028] In the formula, Q j,t CB Indicates the compensation reactive power of the capacitor bank. j,t CB is an integer variable representing the number of capacitor banks at node j at time t. j CB,S Indicates the reactive power capacity of each capacitor bank.

[0029] Based on the above formula, the output power of the capacitor bank is a series of discrete values. The output power of SVG can be continuously adjusted within the rated power capacity range and can be expressed as:

[0030]

[0031] Among them, Q j,t SVG Indicates the output reactive power of SVG, It represents the maximum output reactive power of SVG at node j.

[0032] Assuming that CB and SVG are installed on the same node, and they can be combined into a single device, it can be simplified to:

[0033]

[0034] Among them, N j CB Represents the maximum number of capacitor banks installed on node j. The output power of each CB group is a series of discrete values, which depends on the number of CB groups connected. When the rated output power of SVG is greater than half of the rated output power of a single CB group, the output power of the combined device can be continuously adjusted in the full range.

[0035] Step S2, based on the power flow, constructs an objective function with the goal of minimizing the voltage deviation and the load shedding cost, and performs collaborative optimization of the energy storage and reactive power compensation devices according to the preset photovoltaic energy storage capacity constraints, energy storage charging and discharging constraints, flow constraints, distribution network branch current constraints, distribution network node voltage constraints, second-order cone constraints and objective functions.

[0036] Specifically, the step S2 includes:

[0037] Based on the power flow equation constructed in step S1, a multi-objective planning model including energy storage and reactive compensation devices is proposed. In this example, the energy storage and reactive compensation devices are jointly planned with the minimum voltage deviation and load shedding cost of the distribution network as the objective function. The specific form of the objective function is:

[0038] minF=F vol +F mon

[0039] Among them, F vol , F mon is the voltage deviation and load shedding cost of the distribution network. The specific calculation formula is as follows:

[0040]

[0041]

[0042] Among them, ε j,t + and ε j,t - is an auxiliary variable for power quality assessment and represents the positive and negative voltage deviations on node j at time t; C j,t load,shed is the load shedding cost; P j,t load,shed is the load shedding amount at node j at time t; T is the planning period, and N is the total number of distribution network nodes.

[0043] In this example, photovoltaic energy storage capacity constraints, energy storage charging and discharging constraints, power flow constraints, distribution network branch current constraints, distribution network node voltage constraints, and second-order cone constraints are set as follows:

[0044] 1) PV and energy storage capacity constraints: Set the limits on accessible PV and energy storage capacity based on the nature of the distribution network.

[0045]

[0046]

[0047] In the formula, E PVj is the energy storage capacity connected to node j, E ess,j,min , E ess,j,max is the minimum and maximum energy storage capacity that node j can access; E essj is the photovoltaic capacity connected to node j, E PV,j,min , E PV,j,max is the minimum and maximum value of the photovoltaic capacity that can be connected to node j; E is the set of energy storage nodes to be selected.

[0048] 2) Energy storage charge and discharge constraints. Design the charge and discharge constraints according to the conditions of the energy storage equipment itself. The energy storage charge and discharge constraints and energy storage SOC balance constraints are shown below.

[0049]

[0050]

[0051] Where P dch,min , P dch,max is the minimum and maximum value of energy storage discharge power, P dch (t) is the energy storage discharge power at the energy storage time t; P ch,min , P ch,max is the minimum and maximum value of energy storage charging power, P ch (t) is the energy storage charging power at time t; u dch is the energy storage discharge state, u ch It is the energy storage charging state, which limits the energy storage charging and discharging to not be performed at the same time; SOC ess,min , SOC ess,max is the minimum and maximum value of energy storage capacity, SOC ess (t) is the capacity of energy storage at time t; η dch , η ch is the energy storage discharge / charge efficiency.

[0052] 3) Flow constraints. In the distribution network structure, the planning must meet the balance of active power and reactive power. The following formula represents the flow constraint.

[0053]

[0054] Where P ij , Q ij is the active / reactive power of line ij; is the square of the current on line ij; r ij , x ij is the resistance and reactance of line ij; is the load active / reactive power demand of node j; is the load active / reactive power removal amount of node j; P PV,j , P ess,j is the photovoltaic output and energy storage output of node j; B is the set of distribution network nodes, P jk , Q jk is the active / reactive power of line jk, P(j) is the set of distribution network nodes, and k is a distribution network node;

[0055] 4) Distribution network branch current constraints.

[0056]

[0057] In the formula, They are the lower and upper limits of the current in branch ij respectively.

[0058] 5) Distribution network node voltage constraints.

[0059]

[0060] In the formula, ε j,t + and ε j,t - represents the positive and negative voltage deviations on node j at time t, V j,t is the voltage on node j at time t, V rated is the rated voltage;

[0061] 6) Second-order cone constraints. Since the model contains some nonlinear constraints, they are converted into second-order cone constraints as shown below.

[0062]

[0063] in, is the square of the voltage at node j in the distribution network.

[0064] In summary, the present invention discloses a method for optimizing the configuration of reactive power compensation equipment in a substation that synergistically exerts the value of energy storage. A coordination strategy combining various compensation devices (such as energy storage systems and reactive power compensation devices) is adopted to construct a multi-objective optimization model for a distribution network with new energy access to coordinate active power and reactive power. The present invention uses the minimum load shedding cost and the voltage deviation of the distribution network as the objective function to solve the planned capacity and site selection scheme of the reactive power compensation device to improve the flexibility of the distribution network and reduce the risk of load shedding. The present invention optimizes indicators such as load bus voltage deviation, power loss, and load shedding cost, and uses the Distflow equation to couple active power and reactive power, thereby minimizing power loss and effectively coordinating energy storage and reactive power compensation devices. The multi-objective optimization model takes voltage deviation into consideration at the same time, and has a strong credibility for improving the reactive power compensation capability of the power system and ensuring a reliable and stable power supply.

[0065] like Figure 2 As shown, an embodiment of the present application provides an electronic device, which includes a memory 101 for storing one or more programs and a processor 102. When the one or more programs are executed by the processor 102, any method in the first aspect described above is implemented.

[0066] The memory 101, the processor 102 and the communication interface 103 are directly or indirectly electrically connected to each other to achieve data transmission or interaction. For example, these elements can be electrically connected to each other through one or more communication buses or signal lines. The memory 101 can be used to store software programs and modules, and the processor 102 executes various functional applications and data processing by executing the software programs and modules stored in the memory 101. The communication interface 103 can be used to communicate signaling or data with other node devices.

[0067] Among them, the memory 101 can be, but is not limited to, a random access memory 101 (Random Access Memory, RAM), a read only memory 101 (Read Only Memory, ROM), a programmable read-only memory 101 (Programmable Read-Only Memory, PROM), an erasable read-only memory 101 (Erasable Programmable Read-Only Memory, EPROM), an electrically erasable read-only memory 101 (Electric Erasable Programmable Read-Only Memory, EEPROM), etc.

[0068] The processor 102 may be an integrated circuit chip with signal processing capability. The processor 102 may be a general-purpose processor 102, including a central processing unit 102 (CPU), a network processor 102 (NP), etc.; it may also be a digital signal processor 102 (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0069] In the embodiments provided in the present application, it should be understood that the disclosed method and system can also be implemented in other ways. The method and system embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the method and system, method and computer program product according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or the flowchart, and the combination of boxes in the block diagram and / or the flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0070] In addition, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0071] On the other hand, an embodiment of the present application provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by the processor 102, a method as in any one of the first aspects described above is implemented. If the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a U disk, a mobile hard disk, a read-only memory 101 (ROM, Read-Only Memory), a random access memory 101 (RAM, RandomAccess Memory), a disk or an optical disk.

[0072] The above description of the embodiments is to facilitate the understanding and application of the present invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made to the present invention by those skilled in the art based on the disclosure of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for optimizing the configuration of reactive power compensation equipment in a substation with coordinated energy storage value, characterized in that: The method comprises the following steps: Based on the Distflow equation, the physical characteristics of energy storage and reactive compensator are characterized, and the power flow is divided in the distribution network considering factors including the type, quantity, output power, access mode and load of renewable energy generation to coordinate active power and reactive power; Based on the power flow, an objective function is constructed with the goal of minimizing the voltage deviation and load shedding cost. The energy storage and reactive compensation devices are collaboratively optimized according to the preset photovoltaic energy storage capacity constraints, energy storage charging and discharging constraints, flow constraints, distribution network branch current constraints, distribution network node voltage constraints, second-order cone constraints and objective functions.

2. The method for optimizing configuration of reactive power compensation equipment in substations with coordinated energy storage value according to claim 1, characterized in that: The physical characteristics of energy storage are described as follows: In the formula, is the energy storage discharge power at node j at time t, is the maximum energy storage discharge power at node j at time t, is the energy storage charging power at node j at time t, is the energy storage charging power at node j at time t, is the maximum energy storage discharge energy at node j at time t, is the energy storage discharge energy at node j at time t, u dch is the energy storage discharge state, u ch SOC is the energy storage charging state. ess,min , SOC ess,max is the minimum and maximum value of energy storage capacity, SOC ess (t) is the capacity of energy storage at time t.

3. The method for optimizing configuration of reactive power compensation equipment in substations with coordinated energy storage value according to claim 1 is characterized in that: The physical characteristics of the reactive power compensator are described as follows: The reactive power compensation device mainly considers the optimized operation of capacitor banks and static reactive power generators; The operating characteristics of capacitor banks and static VAR generators can be expressed as: In the formula, Q j,t CB Indicates the compensation reactive power of the capacitor bank, D j,t CB represents the number of capacitor banks at node j at time t, Q j CB,S Indicates the reactive power capacity of each capacitor bank; The output power of the static VAR generator can be continuously adjusted within the rated power capacity range and can be expressed as: Among them, Q j,t SVG Represents the output reactive power of the static VAR generator, Q j SVG,max represents the maximum output reactive power of the static VAR generator at node j; Assuming that the capacitor bank and STATCOM are installed at the same node and they can be combined into a single device, it can be simplified to: Among them, N j CB represents the maximum number of capacitor banks installed at node j.

4. The method for optimizing configuration of reactive power compensation equipment in substations with coordinated energy storage value according to claim 1, characterized in that: The specific form of the objective function is: minF=F vol +F mon Among them, F vol , F mon is the voltage deviation and load shedding cost of the distribution network. The specific calculation formula is as follows: Among them, ε j,t + and ε j,t - represents the positive voltage deviation and negative voltage deviation on node j at time t; C j,t load,shed is the load shedding cost; P j,t load,shed is the load shedding amount at node j at time t; T is the planning period, and N is the total number of distribution network nodes.

5. The method for optimizing configuration of reactive power compensation equipment in substations with coordinated energy storage value according to claim 1, characterized in that: The expression of the photovoltaic energy storage capacity constraint is as follows: In the formula, E PVj is the energy storage capacity connected to node j, E ess,j,min , E ess,j,max is the minimum and maximum energy storage capacity that node j can access; E essj is the photovoltaic capacity connected to node j, E PV,j,min , E PV,j,max is the minimum and maximum value of the photovoltaic capacity that can be connected to node j; E is the set of energy storage nodes to be selected; Among them, the expression of energy storage charging and discharging constraint is as follows: Where P dch,min , P dch,max is the minimum and maximum value of energy storage discharge power, P dch (t) is the energy storage discharge power at the energy storage time t; P ch,min , P ch,max is the minimum and maximum value of energy storage charging power, P ch (t) is the energy storage charging power at time t; u dch is the energy storage discharge state, u ch It is the energy storage charging state, which limits the energy storage charging and discharging to not be performed at the same time; SOC ess,min , SOC ess,max is the minimum and maximum value of energy storage capacity, SOC ess (t) is the capacity of energy storage at time t; η dch , η ch is the energy storage discharge / charge efficiency; The expression of power flow constraint is as follows: Where P ij , Q ij is the active / reactive power of line ij; is the square of the current on line ij; r ij , x ij is the resistance and reactance of line ij; is the load active / reactive power demand of node j; is the load active / reactive power removal amount of node j; P PV,j , P ess,j is the photovoltaic output and energy storage output of node j; B is the set of distribution network nodes, P jk , Q jk is the active / reactive power of line jk, P(j) is the set of distribution network nodes, and k is a distribution network node; Among them, the expression of distribution network branch current constraint is as follows: In the formula, are the lower and upper limits of the current of branch ij respectively; The expression of the distribution network node voltage constraint is as follows: In the formula, ε j,t + and ε j,t - represents the positive and negative voltage deviations on node j at time t, V j,t is the voltage on node j at time t, V rated is the rated voltage; The expression of the second-order cone constraint is as follows: in, is the square of the voltage at node j in the distribution network.

6. An electronic device comprising a memory and a processor, characterized in that: The memory is coupled to the processor; wherein the memory is used to store program data, and the processor is used to execute the program data to implement the substation reactive compensation equipment optimization configuration method for coordinated energy storage value as described in any one of claims 1-5 above.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by the processor, the method for optimizing the configuration of reactive power compensation equipment in a substation with coordinated energy storage value as described in any one of claims 1 to 5 is implemented.

8. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the method for optimizing the configuration of reactive power compensation equipment in a substation for collaborative energy storage value as described in any one of claims 1-5 is implemented.

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