Reactive voltage compensation state evaluation method and device of power distribution network, and electronic equipment

Abstract

The invention discloses a reactive voltage compensation state evaluation method and device of a power distribution network and electronic equipment, and relates to the technical field of power distribution network control, and the method comprises the steps: building a global reactive power optimization model, obtaining a reactive power optimization constraint condition, inputting the real-time operation state of the power distribution network into the global reactive power optimization model, and calculating the reactive power compensation state of the power distribution network. And carrying out global reactive power optimization calculation by the global reactive power optimization model by adopting a cross approximation algorithm to obtain a current reactive power voltage compensation state of the power distribution network, and outputting equipment reactive power compensation configuration schemes of each level and each region of the main and distribution networks of the regional power grid according to the current reactive power voltage compensation state. According to the invention, a technical problem of reactive power imbalance caused by increase of complexity of power flow distribution in a power grid due to high permeability of distributed new energy when reactive voltage control of the power distribution network is carried out in related technologies is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network control or other related fields. Specifically, it relates to a method and device for evaluating the reactive power voltage compensation state of a distribution network, and an electronic device. Background Art

[0002] With the large-scale popularization of renewable energy power generation methods represented by wind energy and solar energy globally, the operating environment of the power system is undergoing fundamental changes. Compared with traditional fossil fuel power generation, the significant feature of new energy power generation is that its output power is greatly affected by natural factors such as weather and sunlight, showing high intermittency and uncertainty. At the same time, the access of a large number of new energy power stations has changed the unidirectional flow characteristics of the power flow in each branch of the power grid, thus changing the voltage distribution of the power grid. Moreover, the output of distributed new energy has strong randomness, which will cause voltage fluctuations at the grid connection point and easily lead to problems such as voltage over-limit. In addition, the existing methods for regulating the voltage of the power grid do not make full use of the reactive power regulation resources of distributed new energy power stations. The volatility of the output of distributed power sources is likely to cause frequent actions and repeated regulations of the reactive power equipment in conventional power stations, affecting the safe operation of the power grid and equipment. Therefore, it is necessary to further strengthen the coordinated control of various reactive power regulation resources, improve the hierarchical distributed reactive power voltage control mode of the power grid, and improve the voltage quality of the power grid after the integration of new energy.

[0003] The reactive power optimization regulation technology takes the reactive power compensation capacity and the adjustable tap of the transformer as control variables, and the load node voltage and the reactive power transmitted by the line as state variables. By applying optimization technology methods, under the condition of meeting the requirements of the reactive power load of the power system, it seeks reasonable reactive power compensation points and the optimal reactive power compensation capacity to ensure that the power grid can supply power to users safely, with high quality and economically.

[0004] In traditional power grids, the control of reactive power voltage mainly relies on equipment such as capacitors, reactors, and transformer taps in substations, as well as the reactive power regulation capabilities of some large power plants. However, when a large number of distributed new energy sources are connected to the power grid, the original reactive power voltage control strategy faces many problems. First, the output fluctuations of distributed new energy will cause the voltage at the grid connection point to be unstable and even exceed the allowable voltage range, affecting the normal operation of power equipment. Second, the high penetration rate of distributed new energy means an increase in the complexity of the power flow distribution inside the power grid. Traditional reactive power compensation resources may be difficult to respond to these changes in a timely manner, resulting in an imbalance of reactive power. Third, the access of a large number of distributed new energy sources makes it more difficult for the power grid control layer to supervise the underlying equipment, increasing the complexity and risk of the overall operation of the power grid.

[0005] When dealing with these problems, related technologies often fail to fully utilize the reactive power regulation potential of distributed new energy sources and tend to rely excessively on conventional reactive power regulation equipment. This not only increases the losses of the equipment and reduces the economic efficiency of system operation, but also may cause frequent operation of conventional equipment when the output of new energy fluctuates violently, affecting its service life and the stability of the power grid.

[0006] In response to the above problems, no effective solution has been proposed yet. Summary of the Invention

[0007] Embodiments of the present invention provide a method and device for evaluating the reactive power voltage compensation state of a distribution network, and an electronic device, so as to at least solve the technical problem that in the reactive power voltage control of a distribution network, the high penetration rate of distributed new energy sources increases the complexity of the power flow distribution inside the power grid, resulting in the imbalance of reactive power balance.

[0008] To achieve the above object, according to one aspect of the present application, a method for evaluating the reactive power voltage compensation state of a distribution network is provided. The distribution network includes the main network and the distribution network of regional power grids at multiple voltage levels, and includes: establishing a global reactive power optimization model, where the global reactive power optimization model includes: a calculation model of capacitors and reactors, a reactive power compensation model of centralized grid-connected new energy power stations, and analyzing the reactive power regulation ability of distributed new energy devices in the regional power grid distribution network through an equivalent model method to form a main network reactive power optimization model including the regional power grid distribution network; obtaining reactive power optimization constraint conditions, where the reactive power optimization constraint conditions include the distribution network bus voltage range, the safe current range of lines and transformers, the tap ratio range of on-load tap changers of transformers, and the reactive power source output range; inputting the real-time operation state of the distribution network into the global reactive power optimization model, and the global reactive power optimization model uses the cross approximation algorithm to perform global reactive power optimization calculation to obtain the current reactive power voltage compensation state of the distribution network. During the global reactive power optimization calculation process, a sparse linear programming solution is used for the active power sub-problem, and the augmented Lagrangian function quadratic approximation solution is used for the reactive power sub-problem to obtain an optimal power flow solution that satisfies the reactive power optimization constraint conditions; according to the current reactive power voltage compensation state, output the reactive power compensation configuration schemes of the equipment at all levels and in all regions of the main and distribution networks of the regional power grid.

[0009] Optionally, the global reactive power optimization for the main network of the regional power grid includes: adopting a coordinated secondary voltage control strategy considering multiple reactive power resources to determine the voltage control strategies for each level of substations and new energy power stations in the main network of the regional power grid, where the voltage control strategy includes: a reactive power optimization control strategy based on multiple time dimensions, switching discrete reactive power devices during the period of load base change in the substation, or adjusting new energy power stations during the period of load fluctuation or new energy device grid connection fluctuation in the substation, and the discrete reactive power devices include at least one of the following: capacitors, reactors.

[0010] Optionally, the step of switching discrete reactive power devices during the period of load base change in the substation based on the reactive power optimization control strategy based on multiple time dimensions includes: adding a virtual synchronous condenser to the busbar where the discrete reactive power device is connected, and the reactive power output of the virtual synchronous condenser represents the reactive power change amount superimposed on the basis of the switching of the discrete reactive power device; where the upper limit of the reactive power output represents the reactive power capacity that can be increased by the busbar where the discrete reactive power device is connected, and the upper limit value of the reactive power output is equal to the sum of all unconnected capacitor capacities and the connected reactor capacities; the lower limit of the reactive power output represents the reactive power capacity that can be reduced by the busbar, and the upper limit value of the reactive power output is equal to the sum of all connected capacitor capacities and the unconnected reactor capacities; using the reactive power output as the generator output, and switching discrete reactive power devices through the virtual synchronous condenser during the period of load base change in the substation.

[0011] According to another aspect of the embodiments of the present invention, there is also provided a reactive voltage compensation state evaluation device for a distribution network. The distribution network includes a main network and a distribution network of regional power grids at multiple voltage levels, and the device includes: a model establishment unit for establishing a global reactive power optimization model, where the global reactive power optimization model includes: a calculation model of capacitors and reactors, a reactive power compensation model of centralized grid-connected new energy power stations, and an analysis of the reactive power regulation capabilities of distributed new energy devices in the regional power grid distribution network through an equivalent model method to form a main network reactive power optimization model including the regional power grid distribution network; a constraint condition acquisition unit for acquiring reactive power optimization constraint conditions, where the reactive power optimization constraint conditions include the distribution network bus voltage range, the safe current range of lines and transformers, the tap ratio range of on-load tap changers of transformers, and the reactive power source output range; a reactive power optimization unit for inputting the real-time operating state of the distribution network into the global reactive power optimization model, and the global reactive power optimization model uses the cross approximation algorithm to perform global reactive power optimization calculations to obtain the current reactive voltage compensation state of the distribution network. During the global reactive power optimization calculation process, the sparse linear programming solution method is used for the active power sub-problem, and the augmented Lagrangian function quadratic approximation solution is used for the reactive power sub-problem to obtain an optimal power flow solution that satisfies the reactive power optimization constraint conditions; a reactive power compensation unit for outputting a reactive power compensation configuration plan for devices at all levels and in all regions of the main and distribution networks of the regional power grid according to the current reactive voltage compensation state.

[0012] According to another aspect of the embodiments of the present invention, there is also provided a computer-readable storage medium. The computer-readable storage medium includes a stored computer program, where when the computer program runs, it controls the device where the computer-readable storage medium is located to execute the reactive voltage compensation state evaluation method for the distribution network in any one of the above.

[0013] According to another aspect of the embodiments of the present invention, there is also provided an electronic device including one or more processors and a memory. The memory is used to store one or more programs, where when the one or more programs are executed by the one or more processors, the one or more processors are caused to implement the reactive voltage compensation state evaluation method for the distribution network in any one of the above.

[0014] According to another aspect of the embodiments of the present invention, there is also provided a computer program product including a computer program. When the computer program is executed by a processor, it implements the steps of the reactive voltage compensation state evaluation method for the distribution network in any one of the above.

[0015] In the present disclosure, a global reactive power optimization model is established. The global reactive power optimization model includes: a calculation model of capacitor reactors, a reactive power compensation model of centralized grid-connected new energy power stations, and an analysis of the reactive power regulation capabilities of distributed new energy devices in the regional power grid distribution network through an equivalent model method to form a main grid reactive power optimization model including the regional power grid distribution network; reactive power optimization constraint conditions are obtained, where the reactive power optimization constraint conditions include the distribution network bus voltage range, the safe current range of lines and transformers, the tap ratio range of on-load tap changers of transformers, and the output range of reactive power sources; the real-time operating state of the distribution network is input into the global reactive power optimization model, and the global reactive power optimization model uses the cross approximation algorithm to perform global reactive power optimization calculations to obtain the current reactive power voltage compensation state of the distribution network. During the global reactive power optimization calculation process, a sparse linear programming solution method is used for the active power sub-problem, and an augmented Lagrangian function quadratic approximation solution is used for the reactive power sub-problem to obtain an optimal power flow solution that satisfies the reactive power optimization constraint conditions; according to the current reactive power voltage compensation state, a reactive power compensation configuration plan for the equipment at all levels and in all regions of the main and distribution networks of the regional power grid is output.

[0016] From the above disclosure content, a reactive power regulation area model for each voltage level can be automatically formed according to the grid structure of the main and distribution networks of the power grid. Considering the original reactive power compensation equipment, dynamic reactive power support equipment, distributed photovoltaics and other reactive power regulation equipment in the area, the reactive power voltage compensation capabilities of the area are dynamically evaluated, and a reactive power compensation configuration plan for the equipment at all levels and in all regions of the main and distribution networks is proposed accordingly, realizing the reactive power balance of the distribution network, solving the problem of inaccurate reactive power compensation configuration on the load side of the power grid, and improving the reliability and security of the power grid operation. Thus, when performing reactive power voltage control on the distribution network in related technologies, the high penetration rate of distributed new energy increases the complexity of the power flow distribution inside the power grid, resulting in the technical problem of reactive power balance disorder. Brief Description of the Drawings

[0017] The drawings described herein are used to provide a further understanding of the present invention and form a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 is a flowchart of an optional method for evaluating the reactive power voltage compensation state of a distribution network according to an embodiment of the present invention;

[0019] Figure 2 is a structural diagram of a four-level global collaborative autonomous optimization control of a main and distribution network of a distribution network according to an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of an equivalent machine model for reactive power regulation of a substation capacitor reactor according to an embodiment of the present invention;

[0021] Figure 4 It is a schematic diagram of a reactive power regulation equivalent machine model for a centralized grid-connected new energy power station in reactive power optimization according to an embodiment of the present invention;

[0022] Figure 5 It is a schematic diagram of a reactive power regulation equivalent machine model for distributed new energy in a distribution network according to an embodiment of the present invention;

[0023] Figure 6 It is a flowchart of an optional cross-approximation optimal power flow algorithm according to an embodiment of the present invention;

[0024] Figure 7 It is a schematic diagram of an optional reactive power and voltage compensation state evaluation device for a distribution network according to an embodiment of the present invention;

[0025] Figure 8 It is a structural block diagram of an electronic device according to an embodiment of the present application. Detailed implementation manners

[0026] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order different from those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0028] To facilitate the understanding of the present invention by those skilled in the art, the following explains some terms or nouns involved in the embodiments of the present invention:

[0029] Distribution Transformer Substation, also known as the distribution transformer in the distribution network and its supporting substation facilities, is a key link between the power system from the substation to the user's power supply line. In the present invention, the Distribution Transformer Substation refers to a small substation in the distribution network responsible for voltage conversion and distribution. These substations are usually equipped with an Automatic Voltage Control (AVC) substation for local monitoring and control of reactive power and voltage levels. In the load-side hybrid active reactive voltage optimization control system, the AVC substation of the transformer can calculate and report its reactive power resource regulation ability in real time, including the status and regulation ability of reactive power devices such as connected distributed photovoltaic inverters, decentralized energy storage batteries, capacitors, etc., so as to participate in the overall reactive voltage optimization calculation and coordinated control.

[0030] Area Control Voltage Control (AVC), that is, the automatic voltage control system at the regional level, is one of the core components of the regional power grid control center. Its main responsibility is to monitor and optimize the control of voltage and reactive power in the jurisdiction area in real time to maintain the grid voltage stable within the allowable range and ensure the safe operation of the power system. The Area Control Voltage Control (AVC) collects the real-time operation data of each substation, new energy power station, distribution network, etc., and uses advanced optimization algorithms to calculate the optimal reactive power compensation state and voltage setting value of each control point, and then issues these control instructions to each substation to adjust the reactive power resources in the grid, such as the reactive power output of generators, the switching state of capacitors / reactors, the tap position of transformers, etc. In the present invention, the Area Control Voltage Control (AVC) is responsible for the global reactive power optimization calculation. According to the reactive power regulation ability sent by the distribution network AVC and the global optimization goal, it calculates the reactive power setting value of each 10kV feeder and cooperates with the distribution network AVC to achieve the voltage coordinated control between the main and distribution networks.

[0031] The augmented Lagrangian function is a mathematical tool used to solve optimization problems with equality and inequality constraints. It is an extension of the Lagrange multiplier method. When solving the reactive voltage optimization problem, the operating state of the power system is restricted by a series of constraints, including but not limited to voltage range constraints, power constraints, equipment operation constraints, etc.

[0032] The dual relaxation simplex method is an optimization algorithm for solving linear programming problems. In the optimization of the power system, especially in the active power sub-problem, due to the number of constraints usually being much larger than the number of variables, the original form of the simplex method may be less efficient.

[0033] Static Var Compensator (SVC), a static device that controls the voltage of the power system by adjusting the reactive power it outputs.

[0034] Static Var Generator, SVG for short, is a reactive power compensation device that generates an AC voltage in phase with the system voltage through a voltage source inverter. By adjusting the amplitude and phase of the inverter output voltage, it can accurately adjust the output reactive power within a wide range and realize the reactive power conversion from inductive to capacitive.

[0035] The following embodiments of the present invention can be applied to systems / applications / devices for reactive voltage compensation status evaluation of various distribution networks. The technical solution adopted by the present invention is as follows: first, a global reactive power optimization calculation model is constructed, which mainly includes a calculation model of a capacitor, a centralized grid-connected new energy station model, and a distribution network distributed new energy model; then reactive power optimization constraints are proposed; then, a cross-approximation algorithm is used for calculation, and a sparse linear programming solution is performed for the active sub-problem, and then an augmented Lagrangian function quadratic approximation solution is performed for the reactive sub-problem. In this way, a dynamic evaluation of the reactive voltage compensation capability of the region is achieved, and a reactive power compensation configuration plan for equipment at all levels and in each region of the main distribution network is proposed in a targeted manner.

[0036] The present invention can provide a comprehensive reactive voltage evaluation method for the hierarchical regions of the power grid covering the high-voltage distribution network on the load side and the medium- and low-voltage distribution network on the medium- and low-voltage sides. It can automatically form reactive control regional models for each voltage level according to the structure of the main distribution network of the power grid, comprehensively consider the original reactive compensation equipment, dynamic reactive support equipment, distributed photovoltaic and other reactive regulation equipment in the region, dynamically evaluate the reactive voltage compensation capability of the region, and propose reactive compensation configuration plans for equipment at all levels and in all regions of the main distribution network.

[0037] The present invention is described in detail below in conjunction with various embodiments.

[0038] Embodiment 1

[0039] According to an embodiment of the present invention, an embodiment of a method for evaluating the reactive voltage compensation status of a distribution network is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0040] According to one aspect of the present application, a method for evaluating reactive voltage compensation status of a distribution network is provided, wherein the distribution network includes a regional main power grid and a regional distribution grid of multiple voltage levels.

[0041] Figure 1 is a flow chart of an optional method for evaluating reactive voltage compensation status of a distribution network according to an embodiment of the present invention, such as Figure 1 As shown, the method comprises the following steps:

[0042] Step S101, establishing a global reactive power optimization model, wherein the global reactive power optimization model includes: a calculation model of capacitors and reactors, a reactive power compensation model of centralized grid-connected new energy stations, and analyzing the reactive power regulation capability of distributed new energy equipment in the regional power distribution network by means of an equivalent model, thereby forming a main network reactive power optimization model including the regional power distribution network.

[0043] In this embodiment, it is necessary to construct a global reactive power optimization model to evaluate and optimize the reactive power distribution of the entire regional power grid. In the process of model establishment, it is necessary to comprehensively consider a variety of reactive power regulation resources, including capacitors and reactors, centralized grid-connected new energy stations, and distributed new energy equipment in the distribution network. For the capacitor reactor calculation model, as a commonly used reactive power compensation device in the power grid, the calculation model of the capacitor reactor should reflect the reactive power contribution of these devices under different states. In the global reactive power optimization model, the calculation model of the capacitor reactor converts the regulation capability of the capacitor reactor into a continuously variable reactive power output by introducing the concept of equivalent virtual phase regulator, so as to facilitate the processing of the optimization algorithm.

[0044] It should be noted that for the reactive power compensation model of the centralized grid-connected new energy station, the new energy station, especially the centralized grid-connected wind turbine and photovoltaic power station, has an important impact on the reactive power voltage control of the power grid due to the volatility of its output power. In this embodiment, the construction of the reactive power compensation model of the centralized grid-connected new energy station takes into account the actual operating status and regulation potential of the dynamic reactive power compensation equipment of the wind farm or photovoltaic power station, such as SVG (static var generator) and inverter array.

[0045] As for the reactive power regulation model of distributed renewable energy in regional power grid distribution network: at the distribution network level, the reactive power regulation capability of distributed photovoltaic and energy storage battery equipment is integrated into the reactive power optimization model of the main distribution network in the form of virtual generators by establishing an equivalent model. The AVC system of the distribution network aggregates the information reported by each AVC substation in real time to form the reactive power regulation capability of the feeder root node, and then transmits this information to the global reactive power optimization model, so that it can perform optimization calculations based on the actual situation of reactive power resources in the distribution network.

[0046] Step S102, obtaining reactive power optimization constraint conditions, wherein the reactive power optimization constraint conditions include the distribution network bus voltage range, the line and transformer safety current range, the transformer on-load tap changer ratio range, and the reactive power output range.

[0047] Reactive power optimization constraints are rules that must be followed to ensure safe and stable operation of the power grid. These constraints usually include bus voltage range, safety current limits of lines and transformers, tap change range of on-load tap-changing transformers, and reactive power output range of generators and new energy stations. The setting of constraints ensures that the optimization process does not exceed the safe operation boundaries of power grid equipment, while also taking into account the economy and reliability of system operation.

[0048] Step S103, input the real-time operating status of the distribution network into the global reactive power optimization model, and the global reactive power optimization model uses a cross approximation algorithm to perform global reactive power optimization calculations to obtain the current reactive voltage compensation state of the distribution network. In the process of performing global reactive power optimization calculations, a sparse linear programming solution is used for the active power sub-problem, and an augmented Lagrangian function quadratic approximation solution is used for the reactive power sub-problem, so as to obtain an optimized power flow solution that meets the reactive power optimization constraints.

[0049] The real-time operating status of the distribution network, including bus voltage, equipment status, power flow and other information, is input into the established global reactive power optimization model, and the cross-approximation algorithm is used to solve it. The cross-approximation algorithm improves the computational efficiency and convergence by decoupling the active sub-problem and the reactive sub-problem and adopting appropriate optimization solutions respectively. Among them, the active sub-problem is simplified to a linear programming problem and solved by the dual relaxation simplex method. This method reduces the amount of calculation and improves the solution efficiency by relaxing the ineffective constraints. The reactive sub-problem usually has a higher nonlinearity, so the augmented Lagrangian function quadratic approximation algorithm is used to solve it. Based on the multiplier penalty function, this algorithm can effectively handle unconstrained minimization problems. Even when the initial conditions are not ideal, it can converge quickly and obtain the optimal solution that meets the reactive power optimization constraints.

[0050] After obtaining the optimal solution of the global reactive power optimization calculation, that is, the current reactive power voltage compensation state, the next step is to output a specific equipment reactive power compensation configuration plan based on this state.

[0051] Step S104: output reactive power compensation configuration plans for equipment at all levels and in all regions of the regional power grid main distribution network according to the current reactive power voltage compensation state.

[0052] The formulation of the reactive power compensation configuration plan needs to comprehensively consider the reactive power voltage compensation conditions at all levels and regions of the power grid, including the reactive power equipment adjustment of substations and new energy stations, the operating status of phase shifters, the switching strategy of capacitors and reactors, and the reactive power regulation instructions of distributed new energy equipment. In this embodiment, the optimization results can be passed down from the regional power grid control center to each substation and distribution network AVC substation step by step through hierarchical control, and finally the precise adjustment of each control point can be achieved to maintain the stability of the power grid voltage and improve the economy of system operation.

[0053] Through the above steps, a global reactive power optimization model can be established, wherein the global reactive power optimization model includes: a calculation model of capacitor reactors, a reactive power compensation model of centralized grid-connected new energy stations, and an analysis of the reactive power regulation capability of distributed new energy equipment in the regional power distribution network by an equivalent model, so as to form a main network reactive power optimization model including the regional power distribution network; obtain reactive power optimization constraints, wherein the reactive power optimization constraints include the distribution network bus voltage range, the line and transformer safety current range, the transformer on-load tap changer ratio range, and the reactive power output range; input the real-time operation state of the distribution network into the global reactive power optimization model, and the global reactive power optimization model uses a cross approximation algorithm to perform global reactive power optimization calculation to obtain the current reactive voltage compensation state of the distribution network, wherein, in the process of performing the global reactive power optimization calculation, a sparse linear programming solution is used for the active sub-problem, and an augmented Lagrangian function quadratic approximation solution is used for the reactive sub-problem, so as to obtain an optimized power flow solution that meets the reactive power optimization constraints; according to the current reactive voltage compensation state, output the reactive power compensation configuration plan for the equipment at all levels and in all regions of the regional power distribution network. In this embodiment, a reactive power control regional model of each voltage level can be automatically formed according to the grid structure of the main distribution network of the power grid, and the reactive power regulation equipment such as the original reactive compensation equipment, dynamic reactive support equipment, distributed photovoltaics, etc. in the region are comprehensively considered to dynamically evaluate the reactive voltage compensation capacity of the region, and targeted reactive power compensation configuration schemes for equipment at all levels and in various regions of the main distribution network are proposed to achieve reactive power balance of the distribution network, solve the problem of inaccurate reactive power compensation configuration of the load-side power grid, and improve the reliability and safety of power grid operation, thereby solving the technical problem that when performing reactive voltage control of the distribution network in related technologies, the high penetration rate of distributed new energy increases the complexity of the power flow distribution inside the power grid, resulting in reactive power imbalance.

[0054] Optionally, the global reactive power optimization of the regional power grid main network includes: adopting a coordinated secondary voltage control strategy that takes into account multiple reactive resources to determine the voltage control strategy for substations and new energy stations at all levels of the regional power grid main network, wherein the voltage control strategy includes: a reactive power optimization control strategy based on multiple time dimensions, switching on and off discrete reactive equipment during the period of load basis changes in the substation, or adjusting new energy stations during the period of load fluctuations in the substation or the period of fluctuations in the access of new energy equipment, and the discrete reactive equipment includes at least one of the following: capacitors and reactors.

[0055] Among them, when the regional power grid performs global reactive power optimization, the reactive resources and voltage levels of substations and new energy stations at all levels can be comprehensively managed by coordinating the secondary voltage control strategy, so as to achieve the optimal configuration and dynamic adjustment of reactive voltage resources in the region, ensure the voltage quality, and maximize the reactive regulation potential of new energy stations. Coordinated secondary voltage control is mainly divided into two levels: the first level is the global reactive power optimization at the regional level, for example, by considering the grid model of 220kV to 35kV voltage levels, evaluating and setting the optimization targets of each voltage level, including the central bus voltage; the second level is the local control at the substation and new energy station level. Based on the optimization targets of the first level, a multi-objective reactive power optimization algorithm is used to ensure that the 10kV to 35kV bus voltage of the substation is qualified, and at the same time optimize the reactive output of the new energy station to assist in system voltage regulation.

[0056] In addition, the reactive power optimization control strategy based on multiple time dimensions adjusts the configuration of reactive resources on different time scales according to the real-time status and forecast information of the power grid. This strategy takes into account the operating characteristics and requirements of the power grid in different time periods, and divides reactive power control into basic change periods and fluctuation periods to adapt to the diverse needs of the power grid.

[0057] It should be noted that two voltage change periods need to be considered in this embodiment. For the basic change period, it refers to the period when the grid load shows a relatively stable trend, such as low load at night or non-peak time on weekends. During this period, due to the relatively stable load, the regulation of discrete reactive equipment (such as capacitors and reactors) becomes the first choice, because the operating cost of such equipment is low, and the effect can be maintained for a considerable period of time after one adjustment. The fluctuation period includes the rapid change period between the peak and trough of the load, and the online power fluctuation period caused by weather changes of new energy equipment (such as wind turbines and photovoltaic power stations). During these periods, the regulation demand of reactive resources is more frequent and dynamic. At this time, the reactive output of the new energy station is adjusted first. By using their rapid response characteristics, the voltage fluctuation of the power grid can be more effectively responded to, and the frequent operation of conventional reactive equipment can be reduced, thereby improving the economy of the system and the service life of the equipment.

[0058] Optionally, based on the reactive power optimization control strategy of multiple time dimensions, the step of switching on discrete reactive equipment during the period of load basis change of the substation includes: adding a virtual phase regulator to the bus to which the discrete reactive equipment is connected, and the reactive output of the virtual phase regulator represents the reactive power change superimposed on the basis of switching on the discrete reactive equipment; wherein the upper limit of the reactive output represents the reactive capacity that can be increased by the bus to which the discrete reactive equipment is connected, and the upper limit value of the reactive output is equal to the sum of all uninvested capacitor capacities and invested reactance capacities; the lower limit of the reactive output represents the reactive capacity that can be reduced by the bus, and the upper limit value of the reactive output is equal to the sum of all invested capacitor capacities and uninvested reactance capacities; the reactive output is used as the generator output, and the discrete reactive equipment is switched on during the period of load basis change of the substation through the virtual phase regulator.

[0059] Virtual phase regulators are used to simulate the regulation capacity of discrete reactive devices in substations, such as capacitors and reactors. The basic principle is to treat the capacitors and reactors of the substation as an adjustable reactive source in the reactive optimization calculation. That is, a virtual phase regulator is added to the busbar of the substation. Its reactive output can be expressed as the reactive change superimposed on the current capacitor and reactor switching state. The upper limit of the reactive output of the virtual phase regulator is calculated as the sum of the total capacity of all unused capacitors and the total capacity of the reactors that have been put into use in the substation. This calculation method reflects the maximum reactive support capacity that the substation can provide to the system by increasing the switching of capacitors when the existing capacitors are not fully utilized and the reactors have played a role. The lower limit of the reactive output of the virtual phase regulator is the sum of the total capacity of all used capacitors and the total capacity of unused reactors. This means that when the capacitors have been put into operation but the reactors have not yet been put into operation, the substation can absorb or reduce the maximum reactive capacity by reducing the switching of capacitors or increasing the use of reactors.

[0060] Optionally, the step of adjusting the new energy station during the period of fluctuation in the access to the grid of new energy equipment includes: obtaining the upper and lower limits of the bus voltage of the new energy station; establishing an equivalent machine model for reactive power regulation on the low-voltage side bus of the new energy station, and inputting the upper and lower limits of the bus voltage of the new energy station into the equivalent machine model to constrain the voltage of the equivalent machine model; adjusting the equivalent machine model according to the operating status of the dynamic reactive power compensation device, the wind turbine and the photovoltaic inverter array, and outputting the reactive power optimization parameters of the new energy station.

[0061] During the period of fluctuations in the access to the Internet of new energy equipment, the output of new energy equipment such as wind turbines and photovoltaic inverters is uncertain, and their reactive power regulation capability is crucial to the stability of the grid voltage. On the low-voltage side busbar of the new energy station, an equivalent machine model of reactive power regulation is established, which can equivalently reflect the reactive power regulation resources of the new energy station, including the reactive power regulation capability of dynamic reactive power compensation devices, wind turbines and photovoltaic inverters.

[0062] Optionally, the global reactive power optimization of the regional power grid main network also includes: when solving the active power sub-problem, using the dual relaxed simplex strategy for global reactive power optimization, wherein all ineffective constraints are relaxed and do not participate in the calculation of the basic constraint equations; when solving the reactive power sub-problem, using the augmented Lagrangian function quadratic approximation algorithm for global reactive power optimization, by constructing an augmented Lagrangian function and iteratively solving the linear equations.

[0063] The dual relaxation simplex strategy and the quadratic approximation algorithm of the augmented Lagrangian function are two commonly used solution methods in optimization calculations. Among them, the dual relaxation simplex strategy is to transform the original problem into a dual problem when facing a large-scale linear programming problem, and to simplify the calculation process and improve the solution efficiency by relaxing the ineffective constraints. In the global reactive power optimization of regional power grids, the reactive subproblem usually has the characteristics of a linear relationship. The dual relaxation simplex strategy makes the basic constraint equation more refined, thereby accelerating the convergence speed and calculation efficiency. The quadratic approximation algorithm of the augmented Lagrangian function is mainly used to solve the reactive subproblem. Since the reactive subproblem usually involves high nonlinearity and complex constraints, the direct application of linear programming methods may not achieve the ideal solution effect. By constructing the augmented Lagrangian function to deal with optimization problems with equality and inequality constraints, the quadratic approximation method can quickly find the optimal solution even when the initial solution is not ideal.

[0064] Optionally, the real-time operating status includes real-time power flow data of the power grid, the bus voltage level, the current output status of the reactive power source and the real-time position of the transformer tap. The reactive voltage compensation status evaluation method of the distribution network also includes: sampling the global reactive optimization model each time the optimized power flow solution is calculated, and adjusting the voltage of the distribution network based on the real-time operating status by adjusting the control voltage variable value, wherein the voltage variable value includes: the reactive output of the generator, the transformer tap position and the switching status of the discrete reactive device.

[0065] In the reactive voltage compensation status evaluation process of the distribution network, the model adjusts the voltage of the distribution network by adjusting the control voltage variable values, which mainly include the reactive output of the generator, the position of the transformer tap, and the switching status of discrete reactive devices (such as capacitors and reactors). During each optimization calculation, the model automatically adjusts these variables based on the current real-time operating status to achieve the optimal voltage compensation effect, ensuring that the power grid can adjust reactive resources in time and maintain voltage stability when facing load fluctuations or changes in equipment status.

[0066] Optionally, for the regional power distribution network, it also includes: a two-stage main distribution network voltage coordination control strategy based on the global reactive power optimization target, which performs voltage coordination control on the regional power main network and the regional power distribution network, wherein the two-stage main distribution network voltage coordination control strategy includes: in the first stage, in the regional dispatching automatic voltage control system AVC, the voltage optimization value of the 10kV bus is targeted, and the global reactive power optimization strategy of the regional power grid main distribution coordination is used to calculate the reactive power regulation strategy of each 10kV feeder; in the second stage, in the automatic voltage control system AVC corresponding to the regional power distribution network, a control model is constructed with the constructed 10kV feeder coordination control area as the object, and the total reactive power setting value of the feeder area root node calculated by the regional dispatching automatic voltage control system AVC is targeted, and the voltage of each load distribution transformer is qualified as a constraint condition, and the reactive power regulation instructions of the adjustable distributed new energy equipment in the 10kV feeder coordination control area are calculated, and the reactive power regulation instructions are sent to the distribution transformer AVC substation for execution.

[0067] Through the two-stage control strategy, the main distribution network voltage coordinated control can ensure the global reactive power optimization target while taking into account the voltage quality control within the distribution network, realizing multi-level reactive power voltage optimization from macro to micro, and improving the economy and reliability of power grid operation. This strategy is particularly suitable for power grids with high penetration of new energy access, and can better cope with the randomness and intermittency of new energy generation, ensuring the stable operation of the power grid under complex conditions.

[0068] Another optional specific implementation is described in detail below.

[0069] This implementation method takes into account the fluctuation of distributed photovoltaic output and the level of system voltage fluctuation, and also takes into account the original reactive compensation equipment on the load side of the power grid. According to the reactive demand of the power grid, a regional voltage automatic adjustment system framework is proposed, and a multi-device reactive compensation configuration plan is proposed. The main technical solutions adopted include: a comprehensive evaluation method for the reactive voltage of the grid layered and zoned covering the high-voltage distribution network on the load side and the medium and low-voltage distribution network, automatically forming a reactive control regional model of each voltage level according to the grid structure of the main distribution network, comprehensively considering the original reactive compensation equipment, dynamic reactive support equipment, distributed photovoltaic and other reactive adjustment equipment in the region, dynamically evaluating the reactive voltage compensation capacity of the region, and proposing reactive compensation configuration plans for equipment at all levels and regions of the main distribution network.

[0070] Figure 2 is a structural diagram of a four-level global coordinated autonomous optimization control of a distribution network main distribution according to an embodiment of the present invention, as shown in the figure. Figure 2 As shown in the overall architecture of hybrid active reactive power and voltage optimization coordinated control on the load side of the regional power grid, Figure 2There are four levels in the system. The first level is: global reactive power optimization of regional power grid main distribution coordination; the second level includes: multiple 220-110-35KV coordination areas; the third level includes: 220kv load center station phase shifter optimization control, substation optimization control and distribution network AVC optimization control; the fourth level includes: phase shifter AVC substation, substation monitoring system and substation AVC substation optimization control. Through the global reactive power optimization technology of main distribution coordination and the coordinated control technology of transmission and distribution voltage of main distribution coordination, the reactive voltage automatic control of regional power grid main distribution coordination is realized.

[0071] First, the overall optimization target of the regional main distribution network is given by the global reactive power optimization calculation of the main distribution network. The power grid model is established with the 220kV-35kV power grid within the scope of the regional power grid as the object, considering the reactive power regulation capabilities of capacitors, reactors and centralized grid-connected new energy stations in the regional power grid, and the reactive power regulation resources such as distributed power sources in the 10kV distribution network are incorporated into the 10kV bus of the regional power grid through the equivalent model, so as to establish the reactive power optimization model of the main distribution network including the distributed power sources of the regional distribution network. By performing the optimal power flow calculation of reactive power optimization, the voltage optimization target value of the busbars at all levels of the regional power grid can be given.

[0072] Secondly, at the level of the regional power grid main grid, a coordinated secondary voltage control method taking into account a variety of reactive resources is used to calculate the voltage control strategies of substations and new energy stations at all levels of the regional power grid main grid. For substations at all levels in the regional power grid, a multi-objective reactive optimization control method is adopted. While ensuring that the voltage of each bus is qualified, the voltage optimization control targets of 220kV, 110kV and 35kV buses given by the global reactive optimization are followed; for the centralized 110kV and 35kV small hydropower and new energy stations in the regional power grid, the bus of the upper substation connected to the grid is used as the central bus, and a coordinated secondary voltage control area is constructed. The central bus voltage given by the global reactive optimization is used as the target to calculate the control strategies of each new energy station. In terms of coordinated control of substations and new energy sites, a multi-time dimension reactive power optimization method is adopted. Through day-ahead and day-intraday rolling reactive power optimization, discrete reactive equipment such as capacitors and reactors in the substation are prioritized for switching on and off during the basic change period of substation load. During the period of load or new energy access fluctuations, new energy sites are prioritized for adjustment, thereby making full use of the new energy site's own adjustment capabilities and reducing the number of reactive equipment operations.

[0073] Third, at the distribution network level of the regional power grid, a two-stage main and distribution network voltage coordinated control decision-making method based on the global reactive power optimization goal is adopted to achieve the coordinated control of the main network and the distribution network voltages. First, the first-stage decision is made. In the local dispatching AVC, taking the optimized value of the 10 kV bus voltage of the substation given by the global reactive power optimization of the main and distribution coordination as the target value, and taking the reactive power regulation capabilities of each 10 kV feeder sent by the distribution network AVC as the regulation means, calculate the reactive power regulation strategies of each 10 kV feeder. Secondly, the second-stage decision is made. In the distribution network AVC, taking the constructed coordinated control area of the 10 kV feeder as the object to build a control model, taking the total reactive power setting value of the root node of the feeder area calculated by the local dispatching AVC as the target, and taking the voltage qualification of each load substation as the constraint condition, calculate the reactive power regulation instructions of the adjustable distributed new energy within the coordinated control area of the 10 kV feeder and send them to the substation AVC substation for execution.

[0074] In the coordinated control of the reactive power and voltage of the regional main network and distribution network in this embodiment, two aspects of reactive power coordination and voltage coordination are mainly considered. At the reactive power coordination level, the main goal is to make full use of the reactive power regulation capabilities of distributed new energy and reduce the operation times of the reactive power equipment in the substation. A reactive power optimization method with multiple time dimensions is adopted. Through day-ahead and intra-day rolling reactive power optimization, during the basic change period of the distribution network load carried by the substation, discrete reactive power equipment such as capacitors and reactors in the substation are preferentially switched; while in other periods, the reactive power regulation resources within the distribution network are preferentially adjusted. At the voltage coordination level, the main goal is to assist the distribution network in voltage regulation when the reactive power regulation capabilities of the distribution network itself are insufficient. An online calculation method for the limit constraints of the main and distribution coordination is adopted. When the reactive power resources within the coordinated control area of the 10 kV feeder are exhausted, the coordinated limit value of the root node voltage is calculated in real time and sent to the local dispatching AVC, and the local dispatching AVC assists in voltage regulation by adjusting the reactive power equipment in the substation.

[0075] The scheme of the global reactive power optimization of the main and distribution coordinated regional power grid is described in detail below.

[0076] The coordinated global reactive power optimization calculation of the regional power grid main distribution gives the voltage optimization control target of the entire network bus, including the 10kV bus of the regional power grid. For example, in the global reactive power optimization calculation, the entire regional power grid model is adopted, and the regulation means such as 110kV hydrothermal power plants, 110kV and 35kV centralized grid-connected new energy sites, and photovoltaic power stations that can be controlled by the regional power grid are comprehensively considered. In addition, through the coordination with the distribution network AVC, the regulation capacity of distributed new energy in the 10kV distribution network in the regional power grid is considered. The voltage control targets given include the voltage optimization targets of 220kV, 110kV, 35kV and 10kV buses within the scope of the regional power grid. The coordinated global reactive power optimization of the main distribution is at the highest level of the regional power grid automatic voltage control of the main distribution coordination. Its main task is: under the premise of meeting the constraints of power grid operation and voltage safety, the reactive power optimization calculation takes the generators and various reactive equipment in the power grid as the regulation means, and the minimum active network loss of the entire power grid as the optimization target, and gives the optimal setting values ​​of the central bus voltage and the reactive power of the key tie line in each partition.

[0077] Reactive power optimization calculation is based on the real-time state estimation results of the power grid. When the state estimation operation quality is not good, the system automatically suspends the reactive power optimization calculation function and makes control decisions based on the voltage plan curve instead.

[0078] Reactive power optimization calculation follows the following principles:

[0079] 1) Select the variables to be optimized, including generator reactive power, phase regulator reactive power, OLTC, capacitor / reactor switching, SVC reactive power, etc.

[0080] 2) The constraints considered include: bus voltage constraints of the entire network, reactive power constraints of each generator, reactive power constraints of each phase regulator and SVC, reactive reserve and threshold power factor constraints of each partition, adjustment range of OLTC, capacitor bank and reactor bank, etc.

[0081] 3) The optimization algorithm ensures convergence and real-time performance.

[0082] 4) The optimization results include: the set values ​​of the central bus voltage and the reactive power of the key tie lines in each zone, the comparison of network losses before and after optimization, the comparison of control variables before and after optimization, and whether various constraints are met before and after optimization.

[0083] 5) When there is no feasible solution, the constraints can be appropriately relaxed and a prompt message can be given.

[0084] As the highest level of the automatic voltage control system of the power grid, the global voltage and reactive power optimization calculation is responsible for the decision-making task of providing the system with the optimization plan for the entire network. It takes the economic operation of the entire system as the optimization goal, comprehensively considers the safety indicators, and gives the set reference value of the bus voltage optimization for control decision-making. In this embodiment, the reactive voltage optimization strategy of the optimal power flow represented by the cross approximation method is adopted to achieve economic dispatch under safety constraints. The optimal power flow and the cross approximation solution are briefly described below.

[0085] The optimal power flow reactive power optimization model (i.e. the optimal operation mode with the smallest network loss under reactive power and voltage constraints) can be written as follows:

[0086]

[0087] in,

[0088] P loss is the grid network loss, unit: MW.

[0089] P ij It is the active power transmitted from branch i to branch j, in MW.

[0090] P ji It is the active power transmitted from branch j to branch i, in MW.

[0091] The following constraints are met:

[0092]

[0093] in:

[0094] Q Gi is the reactive power output of the generator at node i, in Mvar; P Gi is the active output of the generator at node i, in MW; P Di is the active power consumed by the load at node i, in MW.

[0095] Q Di is the reactive load demand of node i, in Mvar; G ij is the branch conductance; B ij is the branch circuit admittance.

[0096] V i is the voltage amplitude of node i. V j is the voltage amplitude at node j. ij is the phase angle between nodes i and j.

[0097]

[0098] Among them, Q Gimin is the minimum output limit of the i-th reactive power source.Gimax is the maximum output limit of the i-th reactive power source.

[0099] Among them, V imin is the safe lower limit of the voltage at the ith node. imax is the safe upper limit of the voltage at the i-th node.

[0100] Among them, t imin is the lower limit of the i-th transformer ratio. imax is the upper limit of the i-th transformer ratio.

[0101] Among them, I ijmax is the reactive power flow limit of the line.

[0102] Where f is the power flow equation.

[0103] The control strategy embodied in this model is to seek the optimal operation mode with the minimum network loss under the reactive power and voltage constraints.

[0104] The above-mentioned reactive power sources include reactive equipment in substations of all levels dispatched by the regional power grid control center, as well as generators or new energy sites and photovoltaic power stations in power plants under the jurisdiction of the control center. The control strategy embodied in the model is to seek the optimal operation mode with the minimum network loss of the entire network under the reactive voltage constraint. The control means of the model include: 1. Generator reactive power / voltage, including hydropower, thermal power, and new energy sites and photovoltaic power stations dispatched by the regional control center, and the model processing method will be described later. 2. Transformer on-load voltage tap changer OLTC. 3. Shunt capacitors and reactors, and the model processing method will be described later. 4. Static VAR compensator (SVC / SVG), including SVC / SVG equipped in power grid substations, and SVC / SVG configured in new energy sites and photovoltaic power stations. 5. Distributed new energy reactive adjustable resources in regional distribution networks, reactive adjustment equipment such as capacitors in distribution networks, etc., and the model processing method will be described later.

[0105] When conducting global reactive power optimization analysis, the goal is to utilize the available reactive power resources in the current power grid and minimize network losses while meeting various feasible safety constraints.

[0106] The following is an explanation of the model of the capacitive reactor in reactive power optimization.

[0107] When performing global reactive power optimization, the goal is to utilize the available reactive power resources in the current power grid and minimize network losses while meeting various feasible safety constraints. Among the reactive power resources, the capacitor reactor of the substation should also be taken into account to achieve coordinated control with the generator. Since the capacitor reactor is a discrete adjustment variable, if it is directly entered into the optimization model, the convergence of the algorithm cannot be guaranteed, and it will not be feasible to use it in an actual closed-loop control system. In fact, at the level of global reactive power optimization, what is more concerned is the optimal distribution of reactive voltage, and there is no need to give a direct control action strategy for the capacitor reactor (its control action strategy is given by the hierarchical substation control calculation module). Therefore, in global reactive power optimization, what needs to be paid attention to is if the reactive regulation capacity of the substation is put together with the reactive regulation capacity of the power plant generator, after comprehensive coordination, under certain constraints, what kind of optimization state the power grid can achieve, and this optimization state is used as the target of subsequent hierarchical voltage control.

[0108] Figure 3 is a schematic diagram of an optional reactive power regulation equivalent machine model of a substation capacitor reactor according to an embodiment of the present invention, such as Figure 3 As shown in the figure, in the global reactive power optimization, a virtual phase regulator can be added to the busbar to which the capacitor reactor is connected, and its reactive power output is recorded as Q c .

[0109] Q c Indicates the reactive power change added on the basis of switching of base state capacitor reactor, initial state is 0. Its upper limit It indicates the reactive capacity that can be added to the busbar, which is numerically equal to the sum of all the unused capacitor capacity and the used reactance capacity. Q c It indicates the reactive capacity that can be reduced for the bus, which is numerically equal to the sum of all the capacitors currently in use and the reactances not in use.

[0110] When performing optimal power flow calculation, Q c As the generator output, expanded to phase Q g And add the following to the constraint condition of formula (4):

[0111]

[0112] in V i are the upper and lower limits of the substation bus voltage, Q Gi is the upper and lower limits of reactive power output. For virtual generators with equivalent values ​​of substations, the upper and lower limits are andQ ci .

[0113] Figure 4 is a schematic diagram of a reactive power regulation equivalent machine model of a centralized grid-connected new energy station in an optional reactive power optimization according to an embodiment of the present invention, such as Figure 4 As shown in the figure, among the reactive resources in the regional power grid, the adjustable reactive equipment in the centralized grid-connected 110kV and 35kV new energy stations and photovoltaic power stations, including dynamic reactive compensation devices and inverters, should also be taken into account to achieve coordinated control with other substations in the power grid. Since new energy stations and photovoltaic power stations contain a large number of wind turbines and inverters, it is impossible to model each wind turbine and inverter separately in the dispatching center. Therefore, it is necessary to establish an equivalent machine model for new energy stations and photovoltaic power stations before they can be included in the global reactive optimization.

[0114] In the new energy station or photovoltaic power station, the dynamic reactive compensation device and photovoltaic array connected to the low voltage side are controlled by the AVC substation in the photovoltaic power station. Therefore, an equivalent machine model of reactive power regulation is established on the 35kV and 10kV busbars on the low voltage side of the new energy station. When performing reactive power optimization optimal power flow calculation, these equivalent generators are expanded to the phase Q g And add the following constraints to the constraints of formula (2):

[0115]

[0116] in V i It is the upper and lower limits of the bus voltage of the new energy station. It is the upper and lower limits of the reactive power output of the new energy equivalent machine. The adjustable reactive power range is calculated and uploaded in real time by the AVC substation in the new energy station / photovoltaic power station according to the operating status of the dynamic reactive compensation device (SVC / SVG) and the wind turbine and photovoltaic inverter array.

[0117] The following explains the model of distributed renewable energy in the distribution network in reactive power optimization.

[0118] In the coordinated global reactive power optimization of the regional power grid, it is necessary to incorporate the regulation capability of the distributed reactive resources in the distribution network of the regional power grid into the global unified reactive power optimization calculation. In order to achieve this goal, based on the voltage coordinated control architecture of the four-level main and distribution networks, a reactive power regulation model of the distribution network is established in the reactive power optimization model of the regional power grid.

[0119] Figure 5 is a schematic diagram of a reactive power regulation equivalent machine model of a distribution network distributed renewable energy according to an embodiment of the present invention, such as Figure 5 As shown, including:

[0120] 1) In the AVC substation of the distribution network transformer, the increase and decrease reactive power regulation capabilities of the reactive resources that can be regulated and controlled by the substation are calculated in real time, including the distributed photovoltaic inverters, distributed energy storage batteries, capacitors and other reactive resources connected to the 10kV transformer and step-up transformer controlled by the substation.

[0121] 2) In the distribution network AVC of the master station, the reactive power regulation capability sent by each substation is received in real time, and according to the 10kV feeder coordination control model established in real time in the distribution network AVC, the reactive power regulation capability is aggregated to the root node of each 10kV feeder, that is, the 10kV busbar outgoing line of the substation.

[0122] 3) In the ground-adjusting AVC of the master station, a reactive power regulation equivalent machine model is established for the outgoing lines with reactive power regulation capability on the 10kV side of the substation.

[0123] When performing optimal power flow calculation for reactive power optimization of regional power grid, these equivalent generators are expanded to phase Q g And add the following constraints to the constraints of formula (3):

[0124]

[0125] in, V i It is the upper and lower limits of the 10kV bus voltage of the substation. It considers the coordination constraint limit of the distribution network AVC transmission based on the planned upper and lower limits. It is the upper and lower limits of reactive power output of 10kV lines with reactive power regulation capability. The adjustable reactive power range is sent by the AVC substation in the substation area and calculated by the distribution network AVC in real time according to the 10kV feeder coordinated control area model.

[0126] The main constraints of the global reactive power optimization analysis and calculation are composed of the equality constraint of formula (2) and the inequality constraint described by formula (3), including: the constraint of the whole network power flow equation (1); the upper and lower limits of the bus voltage: V imin 、V imax ;Safe current range of lines, main transformers and other branches: I ijmax ; Transformer on-load tap changer ratio range: t imax ,t imin ;Regulation range of reactive power sources for conventional power plants, new energy sources and substations: Q Gimin , Q Gimax ; The regulation range of reactive power regulation resources of the 10kV line of the distribution network. On this basis, other related inequality constraints can be added, such as the power limit of the interconnection section and the reactive power coordination limit value of the gateway issued by the superior dispatcher.

[0127] The cross-approximation algorithm for global reactive power optimization is explained below.

[0128] The global reactive power optimization of the regional power grid adopts the cross-approximation algorithm for reactive power optimal power flow. This algorithm utilizes the weak coupling relationship between the active power component and the reactive power component that generally exists in the power system, and according to the convex duality and partial duality theories, adopts the method of active-reactive decoupling cross-approximation to obtain the optimal power flow solution.

[0129] For the convenience of discussion, no distinction is made between the control variables and the state variables, and x P and x Q are used to distinguish the variables closely related to the active power and the reactive power. Then the general optimal power flow problem can be described as follows:

[0130] min f(x P ,x Q )

[0131] s.t.P E (x P ,x Q )=0

[0132] P I (x P ,x Q )≤0

[0133] Q E (x P ,x Q )=0

[0134] Q I (x P ,x Q )≤0 (7)

[0135] where x P includes the active power output P G of the generator and the node voltage phase angle θ; x Q then includes the reactive power output Q G of the reactive power source, the node voltage amplitude V, and the tap ratio t of the adjustable transformer; P E and Q E are the node active and reactive power flow equations respectively; P I and Q I are the inequality constraint conditions closely related to the active power component and the reactive power component respectively.

[0136] Assume that the initial value of Equation (5) is close enough to the optimal value and satisfies the local convexity assumption. Then, according to the conclusions of convex duality and partial duality, Equation (5) is equivalent to:

[0137]

[0138] s.t.P E (x P,x Q ) = 0

[0139] P I (x P ,x Q ) ≤ 0 (8)

[0140] Or equivalently:

[0141]

[0142] s.t. Q E (x P ,x Q ) = 0

[0143] Q I (x P ,x Q ) ≤ 0 (9)

[0144] The λ Q μ Q λ P μ P correspond to the dual variables of equation (5) at the solution point respectively. The constraint conditions of the two sub - problems of equations (6) and (7) are significantly reduced compared with those of the original problem equation (5).

[0145] Since the values of the dual variables at the solution point are not known in advance, a natural method is to alternately solve the two sub - problems of equations (6) and (7) until the x P ,x Q obtained are the same, and the optimal value is solved.

[0146] Note that the reactive power constraint does not appear in equation (6), and the active power constraint does not appear in equation (7). Using the PQ decoupling principle, the variables related to reactive power can be treated as constants in the sub - problem of equation (6), and the variables related to active power can be treated as constants in the sub - problem of equation (7). Therefore, the two sub - problems can be simplified respectively as:

[0147] F Q (x Q ,λ Q ,μ Q ) = min f P (x P )

[0148] s.t. P(x P ) ≤ 0 (10)

[0149] and

[0150] F P (x P ,λ P ,μP ) = min f Q (x Q )

[0151] s.t. Q(x Q ) ≤ 0 (11)

[0152] Solve these two sub - problems. Finally, at the optimal solution, there should be F Q = F P .

[0153] Figure 6 is a flowchart of an optional cross - approximation optimal power flow algorithm according to an embodiment of the present invention. As Figure 6 shown, KPQ is the selection flag for active and reactive power iteration. When it is equal to zero, the active power sub - problem loop iteration is performed; otherwise, the reactive power sub - problem loop iteration is performed. JUDP and JUDQ are the convergence flag bits for active and reactive power respectively, and are set to 1 when converged. When both the active and reactive power sub - problem iterations converge, the sum of JUDP and JUDQ is equal to 2, and the optimal power flow calculation is completed; otherwise, the iteration continues to return.

[0154] In order to make the algorithm achieve the best computational efficiency, according to the characteristics of good linearity of active power optimization in this embodiment, a set of sparse linear programming algorithms is designed for the active power optimization sub - problem; according to the characteristics of strong non - linearity of reactive power voltage, a set of sparse augmented Lagrangian function quadratic approximation algorithms is designed for the reactive power optimization sub - problem. The entire program uses sparse matrices and advanced sparse vector technology, and the computational efficiency is quite high, fully meeting the level of online application.

[0155] The following explains the sparse linear programming solution for the active power sub - problem.

[0156] For the active power sub - problem, considering the good linear relationship between the active power component and the active power flow equation in the power system, the algorithm uses linear programming to approximate the active power sub - problem.

[0157] The objective function of formula (8) is generally expressed as a separable convex function of the active power component x P , and such an active power sub - problem can be approximately regarded as a separable mathematical programming problem that can be solved by the method of dual linear programming.

[0158] The core idea of the dual relaxation LP algorithm: First, the original problem is relaxed. That is, the non - linear or integer constraints are relaxed into continuous linear constraints, and it is transformed into a linear programming (LP) problem. Second, the dual problem is constructed. That is, through the Lagrangian dual theory, the original problem is transformed into a dual problem, and the dual gap is used to guide iterative optimization. Third, the cutting - plane or branch - and - bound method is used. That is, the cutting - plane method (such as Benders decomposition) or branch - and - bound is combined to handle discrete variables, and the optimal solution of the original problem is gradually approximated. The specific steps are as follows: 1. Construct the dual relaxation LP form of the reactive power optimization model; 2. Construct the dual problem; 3. Handle discrete variables (branch - and - bound method); 4. Iteratively solve.

[0159] Linearize the active power sub - problem at the solution point of the K - th approximation, and the resulting incremental model is as follows: at the point, the resulting incremental model is as follows:

[0160]

[0161] s.t.J P Δx P +P(x P )≤0

[0162] |Δx P |≤Δx Pmax (12)

[0163] where the increment J P is the Jacobian matrix of the constraint P(x P ) at , and C P is the cost vector corresponding to the increment Δx P . The second item of the constraint condition is set to prevent the step size of the increment Δx P from being too large, resulting in the failure of the linear relationship to hold.

[0164] Note that most of the elements in the vector Δx P are the increments Δθ of the state variables, and for Δθ, there is no need to directly impose upper and lower bounds; at the same time, similar to the traditional fast decoupled power flow algorithm, the structure and most of the elements of the Jacobian matrix here can be regarded as unchanged during the iterative process, so J P can also be replaced by the constant matrix B′. Re - construct Equation (12) as follows:

[0165]

[0166] s.t.B′Δθ+J G ΔP G =-ΔP L

[0167] L min≤J L Δθ ≤ L max

[0168] ΔP Gmin ≤ ΔP G ≤ ΔP Gmax (13)

[0169] where C θ is the cost vector corresponding to the increment Δθ, and ΔP L is the imbalance of active power. C G is the incremental rate vector of the generator consumption curve. J L is the Jacobian matrix of the line inequality constraint.

[0170] In this embodiment, according to the characteristics of the active sub-problem, a dual relaxation simplex strategy is designed to be implemented by directly applying the duality principle on the basis of the original problem model. All ineffective constraints are relaxed and excluded from the simplex table, so no slack variables appear, and the dimension of the basis matrix is always equal to the total number of variables, which is particularly suitable for dealing with bilateral inequality constraints.

[0171] Specifically, for the dual relaxation LP algorithm of the active sub-problem, it may include: The first step: the program entry of the active sub-problem, first perform the active main iteration, then establish the LP model, find the upper and lower limits of the line constraints, and then establish the basic constraint equation for the initial LP iteration; The second step: establish the monitoring constraint set of the line, and judge whether the monitoring constraint set is empty. If not, determine the incoming constraint in the monitoring set; The third step, judge whether there is an incoming constraint. If so, accumulate LPITER = LPITER + 1. If not, return to the second step; The fourth step: find the sensitivity vector of the incoming constraint and determine the qualified outgoing constraint; The fifth step: judge whether there is an outgoing constraint. If so, calculate the effective Lagrange multiplier, perform a qualification check on the qualified outgoing constraint to find the optimal outgoing constraint, modify the basis matrix, determine its factor table, and find the ΔP G of the generator that does not exceed the limit, select the incoming constraint from the generators, and then continue to judge whether there is an incoming constraint. If not, use forward substitution quickly to solve the new Δθ. For the part without an outgoing constraint, solve the new θ and P G .

[0172] The following describes the quadratic approximation solution method for the augmented Lagrangian function of the reactive sub-problem.

[0173] Compared with the active sub - problem, the non - linearity of the power flow equation in the reactive sub - problem is much higher. In addition, in many cases, the objective function is not a separable convex function with respect to reactive variables. Therefore, the linear programming model is not suitable for dealing with such problems. The augmented Lagrangian function quadratic approximation model is based on the multiplier penalty function, integrating the stability of the penalty function and the rapidity of the Newton method. It has low requirements for initial conditions, is flexible and practical. A large number of actual system examples prove that it is very effective for the approximate solution of the reactive sub - problem.

[0174] Specifically, the solution process of the augmented Lagrangian function quadratic approximation. By transforming the non - linear constraints into a sequential quadratic programming problem, it takes into account both the solution accuracy and the computational efficiency, and is especially suitable for the real - time requirements of reactive power optimization in power systems. In practical applications, parameters need to be adjusted according to the characteristics of the power grid, and a sparse solver is used to accelerate the calculation of the QP sub - problem. The specific steps are as follows: 1. Construct the reactive sub - problem model. 2. Construct the augmented Lagrangian function. (Convert the inequality constraints into equality constraints through the penalty function and construct the augmented Lagrangian function) 3. Quadratic approximation and iterative solution.

[0175] For the reactive sub - problem equation (9), its augmented Lagrangian function can be constructed according to the multiplier penalty function method as follows:

[0176]

[0177] where λ Q is the Lagrangian multiplier vector of the equality constraint Q(x Q ) = 0, and the diagonal matrix R is the penalty coefficient. The augmented Lagrangian function has an important property: if is the multiplier vector at the optimal solution of equation (1.20), and at the same time, the diagonal elements of the penalty coefficient matrix R are sufficiently large, all being Given λ Q and R, this is an unconstrained minimization problem, which can be solved by the Newton method. Through a series of matrix transformations, the solution of equation (12) can ultimately be reduced to the problem of repeatedly iteratively solving the following linear equation system:

[0178]

[0179] where

[0180] Equation (13) has an important characteristic: by reasonably arranging the variable order, the left - hand - side coefficient matrix can have the same structure as the nodal admittance matrix, where each element is a 2×2 block sub - matrix. The algorithm utilizes this characteristic and implements advanced sparse matrix and sparse vector techniques, effectively ensuring the rapidity of the reactive sub - problem calculation and enabling the algorithm to have the ability of online application.

[0181] Through the above embodiments, a hybrid active reactive power voltage optimization and coordination control scheme for the load side is proposed, which comprehensively evaluates the reactive power voltage of the high-voltage distribution network and the medium- and low-voltage distribution network on the load side, automatically forms a reactive power regulation area model for each voltage level according to the grid structure of the main and distribution networks of the power grid, and comprehensively considers the original reactive power compensation equipment, dynamic reactive power support equipment, distributed photovoltaics and other reactive power regulation equipment in the area, dynamically evaluates the reactive power voltage compensation capacity of the area, and proposes a reactive power compensation configuration scheme for the equipment at all levels and in all regions of the main and distribution networks, solving the problem of inaccurate reactive power compensation configuration of the load side power grid and improving the reliability and security of the power grid operation.

[0182] A detailed description will be given below in conjunction with another embodiment.

[0183] Embodiment 2

[0184] A reactive power voltage compensation state evaluation device for a distribution network provided in this embodiment includes a plurality of implementation units, each implementation unit corresponding to each implementation step in the first embodiment above. The specific implementation manner and beneficial effects can refer to the foregoing method embodiment and will not be elaborated here.

[0185] Figure 7 It is a schematic diagram of an optional reactive power voltage compensation state evaluation device for a distribution network according to an embodiment of the present invention. As Figure 7 shown, the reactive power voltage compensation state evaluation device for the distribution network may include: a model establishment unit 71, a constraint condition acquisition unit 72, a reactive power optimization unit 73, and a reactive power compensation unit 74.

[0186] Among them, the model establishment unit 71 is used to establish a global reactive power optimization model. The global reactive power optimization model includes: a calculation model of capacitors and reactors, a reactive power compensation model of centralized grid-connected new energy power stations, and an analysis of the reactive power regulation ability of distributed new energy equipment in the regional power grid through an equivalent model method to form a main network reactive power optimization model including the regional power grid;

[0187] The constraint condition acquisition unit 72 is used to acquire reactive power optimization constraint conditions. The reactive power optimization constraint conditions include the range of distribution network bus voltages, the range of safe currents of lines and transformers, the range of tap ratios of on-load tap changers of transformers, and the range of reactive power source outputs;

[0188] The reactive power optimization unit 73 is used to input the real-time operation state of the distribution network into the global reactive power optimization model, and the global reactive power optimization model uses the cross approximation algorithm to perform global reactive power optimization calculation to obtain the current reactive power voltage compensation state of the distribution network. In the process of performing the global reactive power optimization calculation, the sparse linear programming solution is used for the active power sub-problem, and the augmented Lagrangian function quadratic approximation solution is used for the reactive power sub-problem to obtain the optimal power flow solution that meets the reactive power optimization constraint conditions;

[0189] The reactive power compensation unit 74 is used to output reactive power compensation configuration schemes for equipment at various levels and in various regions of the regional power grid main distribution network according to the current reactive power voltage compensation status.

[0190] The reactive voltage compensation state evaluation device of the above-mentioned distribution network can establish a global reactive power optimization model through the model establishment unit 71, wherein the global reactive power optimization model includes: a calculation model of capacitors and reactors, a reactive power compensation model of centralized grid-connected new energy stations, and an analysis of the reactive power regulation capability of distributed new energy equipment of the regional power distribution network by means of an equivalent model, thereby forming a main network reactive power optimization model including the regional power distribution network, and obtaining reactive power optimization constraints through the constraint condition acquisition unit 72, wherein the reactive power optimization constraints include the distribution network bus voltage range, the line and transformer safety current range, the transformer on-load tap changer ratio range, Reactive power output range, the real-time operating status of the distribution network is input into the global reactive optimization model through the reactive optimization unit 73, and the global reactive optimization model uses the cross approximation algorithm to perform global reactive optimization calculations to obtain the current reactive voltage compensation state of the distribution network. In the process of global reactive optimization calculations, the sparse linear programming solution is used for the active sub-problem, and the augmented Lagrangian function quadratic approximation solution is used for the reactive sub-problem to obtain the optimal flow solution that meets the reactive optimization constraints. The reactive compensation unit 74 outputs the reactive compensation configuration plan for the equipment at all levels and in all regions of the regional power grid main distribution network according to the current reactive voltage compensation state. In this embodiment, a reactive power control regional model of each voltage level can be automatically formed according to the grid structure of the main distribution network of the power grid, and the reactive power regulation equipment such as the original reactive compensation equipment, dynamic reactive support equipment, distributed photovoltaics, etc. in the region are comprehensively considered to dynamically evaluate the reactive voltage compensation capacity of the region, and targeted reactive power compensation configuration schemes for equipment at all levels and in various regions of the main distribution network are proposed to achieve reactive power balance of the distribution network, solve the problem of inaccurate reactive power compensation configuration of the load-side power grid, and improve the reliability and safety of power grid operation, thereby solving the technical problem that when performing reactive voltage control of the distribution network in related technologies, the high penetration rate of distributed new energy increases the complexity of the power flow distribution inside the power grid, resulting in reactive power imbalance.

[0191] Optionally, the reactive voltage compensation state assessment device of the distribution network performs global reactive power optimization on the regional power grid main network, including: a voltage control strategy determination unit, which is used to adopt a coordinated secondary voltage control strategy that takes into account multiple reactive resources, to determine the voltage control strategy for substations and new energy stations at all levels of the regional power grid main network, wherein the voltage control strategy includes: a reactive power optimization control strategy based on multiple time dimensions, switching on and off discrete reactive equipment during the load base change period of the substation, or adjusting the new energy station during the load fluctuation period of the substation or the fluctuation period of the new energy equipment access to the grid, and the discrete reactive equipment includes at least one of the following: capacitors and reactors.

[0192] Optionally, when the reactive voltage compensation state assessment device of the distribution network switches discrete reactive equipment during the load basis change period of the substation, it includes: a phase regulator adding unit, which is used to add a virtual phase regulator to the bus to which the discrete reactive equipment is connected, and the reactive output of the virtual phase regulator represents the reactive change superimposed on the switching of the discrete reactive equipment; wherein the upper limit of the reactive output represents the reactive capacity that can be increased by the bus to which the discrete reactive equipment is connected, and the upper limit value of the reactive output is equal to the sum of all uninvested capacitor capacities and invested reactance capacities; the lower limit of the reactive output represents the reactive capacity that can be reduced by the bus, and the upper limit value of the reactive output is equal to the sum of all invested capacitor capacities and uninvested reactance capacities; a reactive equipment switching unit, which is used to use the reactive output as the generator output, and switch the discrete reactive equipment during the load basis change period of the substation through the virtual phase regulator.

[0193] Optionally, the reactive voltage compensation state assessment device of the distribution network adjusts the new energy station during the period of fluctuation of the new energy equipment access to the grid, and the bus voltage upper and lower limit acquisition unit is used to include: obtaining the upper and lower limits of the bus voltage of the new energy station; establishing an equivalent machine model for reactive power regulation on the low-voltage side bus of the new energy station, and inputting the upper and lower limits of the bus voltage of the new energy station into the equivalent machine model to constrain the voltage of the equivalent machine model; the equivalent machine model adjustment unit is used to adjust the equivalent machine model according to the operating status of the dynamic reactive power compensation device, the wind turbine and the photovoltaic inverter array, and output the reactive power optimization parameters of the new energy station.

[0194] Optionally, when the reactive voltage compensation state assessment device of the distribution network performs global reactive power optimization on the regional power grid main network, it includes: a first optimization unit, which is used to adopt a dual relaxed simplex strategy to perform global reactive power optimization when solving the reactive sub-problem, wherein all ineffective constraints are relaxed and do not participate in the calculation of the basic constraint equations; a second optimization unit, which is used to adopt an augmented Lagrangian function quadratic approximation algorithm to perform global reactive power optimization when solving the reactive sub-problem, by constructing an augmented Lagrangian function and iteratively solving a system of linear equations.

[0195] Optionally, the real-time operating state includes the real-time power flow data of the power grid, the bus voltage level, the current output state of reactive power sources, and the real-time position of transformer tap changers. The reactive power-voltage compensation state evaluation device for the distribution network further includes: a distribution network voltage adjustment unit, configured to sample the global reactive power optimization model. When calculating the optimal power flow solution each time, based on the real-time operating state, adjust the voltage of the distribution network by adjusting the control voltage variable value, where the voltage variable value includes: the reactive power output of the generator, the position of the transformer tap changer, and the switching state of discrete reactive power devices.

[0196] Optionally, for the distribution network of the regional power grid, the reactive power-voltage compensation state evaluation device for the distribution network further includes: a voltage coordinated control unit, configured to perform voltage coordinated control on the regional power grid main network and the regional power grid distribution network based on the two-stage main-distribution network voltage coordinated control strategy of the global reactive power optimization target, where the two-stage main-distribution network voltage coordinated control strategy includes: in the first stage, taking the voltage optimization value of the 10 kV bus as the target in the regional dispatch automatic voltage control system (AVC), using the global reactive power optimization strategy for the main-distribution coordination of the regional power grid, calculate the reactive power regulation strategy for each 10 kV feeder; in the second stage, in the automatic voltage control system (AVC) corresponding to the regional power grid distribution network, taking the constructed 10 kV feeder coordinated control area as the object to construct a control model, taking the total reactive power setting value of the feeder area root node calculated by the regional dispatch automatic voltage control system (AVC) as the target, and taking the voltage qualification of each load distribution network transformer as the constraint condition, calculate the reactive power regulation instructions for the adjustable distributed new energy devices within the 10 kV feeder coordinated control area, and send the reactive power regulation instructions to the AVC substation of the distribution network transformer for execution.

[0197] The above-mentioned reactive power-voltage compensation state evaluation device for the distribution network may further include a processor and a memory. The above-mentioned model establishment unit 71, constraint condition acquisition unit 72, reactive power optimization unit 73, reactive power compensation unit 74, etc. are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to implement corresponding functions.

[0198] The above-mentioned processor includes a kernel, and the kernel retrieves the corresponding program units from the memory. One or more kernels can be set, and the load-side hybrid active reactive power-voltage optimization coordination control is achieved by adjusting the kernel parameters.

[0199] The above-mentioned memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of, for example, read-only memory (ROM) or flash memory (flash RAM), and the memory includes at least one memory chip.

[0200] Embodiment 3

[0201] An embodiment of the present application can provide an electronic deviceFigure 8 is a block diagram of a structure of an electronic device according to an embodiment of the present application. As Figure 8 shown, the electronic device may include: one or more ( Figure 8 only one is shown in the figure) processors 802, a memory 804, a storage controller, and a peripheral interface, where the peripheral interface is connected to a radio frequency module, an audio module, and a display.

[0202] Among them, the memory can be used to store software programs and modules, such as program instructions / modules corresponding to the reactive voltage compensation state evaluation method and device of the distribution network in the embodiment of the present application. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory, that is, implements the above-mentioned reactive voltage compensation state evaluation method of the distribution network. The memory may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memories, or other non-volatile solid-state memories. In some instances, the memory may further include a memory remotely provided with respect to the processor, and these remote memories may be connected to the terminal through a network. Examples of the above network include but are not limited to the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof.

[0203] Those of ordinary skill in the art can understand that Figure 8 the structure shown is only schematic, and the electronic device may also be a terminal device such as a smart phone, a tablet computer, a palm computer, and a mobile Internet device (Mobile Internet Devices, MID), a PAD, etc. Figure 8 It does not limit the structure of the above-mentioned electronic device. For example, the electronic device may further include more or fewer components (such as a network interface, a display device, etc.) than Figure 8 shown in the figure, or have a different configuration from Figure 8 shown in the figure.

[0204] Those of ordinary skill in the art can understand that all or part of the steps in the various reactive voltage compensation state evaluation methods of the distribution network in the above embodiments can be completed by instructing the relevant hardware of the terminal device through a program, and the program can be stored in a computer-readable storage medium. The storage medium may include: a flash drive, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk, or an optical disc, etc.

[0205] Embodiment 4

[0206] The embodiment of the present application also provides a storage medium. Optionally, in this embodiment, the above storage medium may be used to save the program code executed by the reactive voltage compensation state evaluation method provided in Embodiment 1 above.

[0207] According to another aspect of the embodiments of the present invention, there is also provided a computer-readable storage medium, which includes a stored computer program. When the computer program runs, it controls the device where the computer-readable storage medium is located to execute the reactive voltage compensation state evaluation method of the distribution network in any one of the above-mentioned Embodiment 1.

[0208] Optionally, in this embodiment, the above storage medium may be located in any one of the computer terminals in a computer terminal group in a computer network, or in any one of the mobile terminals in a mobile terminal group.

[0209] The present application also provides a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements the steps of the reactive voltage compensation state evaluation method of the distribution network described in various embodiments of the present application.

[0210] The present application also provides a computer program product, which includes a non-volatile computer-readable storage medium. The non-volatile computer-readable storage medium stores a computer program. When the computer program is executed by a processor, it implements the steps of the reactive voltage compensation state evaluation method of the distribution network described in various embodiments of the present application.

[0211] The serial numbers of the above-mentioned embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0212] In the above-mentioned embodiments of the present invention, the descriptions of the various embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0213] In several embodiments provided by the present application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only illustrative. For example, the division of the units can be a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of units or modules can be in an electrical or other form.

[0214] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The foregoing storage medium includes: various media that can store program codes, such as USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks, or optical discs.

[0215] The foregoing are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for evaluating reactive voltage compensation status of a distribution network, characterized in that: The distribution network includes regional power main grids and regional power distribution networks at multiple voltage levels, including: Establishing a global reactive power optimization model, wherein the global reactive power optimization model includes: a calculation model of capacitor reactors, a reactive power compensation model of centralized grid-connected new energy stations, and analyzing the reactive power regulation capability of distributed new energy equipment of the regional power distribution network by means of an equivalent model, so as to form a main network reactive power optimization model including the regional power distribution network; Obtaining reactive power optimization constraint conditions, wherein the reactive power optimization constraint conditions include a distribution network bus voltage range, a line and transformer safety current range, a transformer on-load tap changer ratio range, and a reactive power output range; The real-time operating state of the distribution network is input into the global reactive power optimization model, and the global reactive power optimization model uses a cross approximation algorithm to perform global reactive power optimization calculation to obtain the current reactive voltage compensation state of the distribution network, wherein, in the process of performing the global reactive power optimization calculation, a sparse linear programming solution is used for the active power sub-problem, and an augmented Lagrangian function quadratic approximation solution is used for the reactive power sub-problem to obtain an optimized power flow solution that satisfies the reactive power optimization constraint conditions; According to the current reactive voltage compensation state, reactive power compensation configuration schemes for equipment at all levels and in all regions of the regional power grid main distribution network are output.

2. The state assessment method according to claim 1, characterized in that: The global reactive power optimization for the regional power grid main network includes: A coordinated secondary voltage control strategy taking into account a variety of reactive resources is adopted to determine the voltage control strategies for substations at all levels and new energy stations of the regional power grid main network, wherein the voltage control strategies include: reactive power optimization control strategies based on multiple time dimensions, switching on and off discrete reactive equipment during the period of load basis changes at the substation, or regulating new energy stations during the period of load fluctuations at the substation or the period of new energy equipment access fluctuations, wherein the discrete reactive equipment includes at least one of the following: capacitors and reactors.

3. The state assessment method according to claim 2, characterized in that: Based on the multi-time dimension reactive power optimization control strategy, the steps of switching discrete reactive power equipment during the load base change period of the substation include: A virtual phase regulator is added to the busbar to which the discrete reactive device is connected, and the reactive output of the virtual phase regulator represents the reactive change amount superimposed on the switching of the discrete reactive device; wherein the upper limit of the reactive output represents the reactive capacity that can be increased by the busbar to which the discrete reactive device is connected, and the upper limit value of the reactive output is equal to the sum of all the uninvested capacitor capacities and the invested reactance capacities; the lower limit of the reactive output represents the reactive capacity that can be reduced by the busbar, and the upper limit value of the reactive output is equal to the sum of all the invested capacitor capacities and the uninvested reactance capacities; The reactive power output is used as the generator output, and the discrete reactive equipment is switched in the load basis change period of the substation through the virtual phase regulator.

4. The state assessment method according to claim 2, characterized in that: The steps to adjust the new energy station during the period of fluctuation of new energy equipment grid connection include: Obtaining the upper and lower limits of the bus voltage of the new energy station; Establishing an equivalent machine model for reactive power regulation on the low-voltage side bus of the new energy station, and inputting the upper and lower limits of the bus voltage of the new energy station into the equivalent machine model to constrain the voltage of the equivalent machine model; According to the operating status of the dynamic reactive power compensation device, the wind turbine generator set and the photovoltaic inverter array, the equivalent machine model is adjusted to output the reactive power optimization parameters of the new energy station.

5. The state assessment method according to claim 2, characterized in that: The global reactive power optimization of the regional power grid main network also includes: When solving the active subproblem, the dual relaxed simplex strategy is used for global reactive power optimization. When solving the reactive power subproblem, the augmented Lagrangian function quadratic approximation algorithm is used for global reactive power optimization by constructing the augmented Lagrangian function and iteratively solving the linear equations.

6. The state assessment method according to claim 2, characterized in that: The real-time operation status includes real-time power flow data of the power grid, bus voltage level, current output status of reactive power source and real-time position of transformer tap. The reactive voltage compensation status evaluation method of the distribution network also includes: The global reactive power optimization model is sampled and, each time the optimized power flow solution is calculated, the voltage of the distribution network is adjusted by adjusting the control voltage variable value based on the real-time operating status, wherein the voltage variable value includes: the reactive output of the generator, the transformer tap position and the switching status of the discrete reactive device.

7. The state assessment method according to claim 1, characterized in that: For the regional power distribution network, it also includes: A two-stage main and distribution network voltage coordination control strategy based on the global reactive power optimization target performs voltage coordination control on the regional power grid main network and the regional power grid distribution network, wherein the two-stage main and distribution network voltage coordination control strategy includes: in the first stage, in the regional dispatching automatic voltage control system AVC, the voltage optimization value of the 10kV bus is targeted, and the global reactive power optimization strategy of the regional power grid main and distribution coordination is used to calculate the reactive power regulation strategy of each 10kV feeder; in the second stage, in the automatic voltage control system AVC corresponding to the regional power grid distribution network, a control model is constructed with the constructed 10kV feeder coordination control area as the object, the total reactive power setting value of the feeder area root node calculated by the regional dispatching automatic voltage control system AVC is targeted, and the voltage of each load distribution network transformer is qualified as a constraint condition, the reactive power regulation instructions of the adjustable distributed new energy equipment in the 10kV feeder coordination control area are calculated, and the reactive power regulation instructions are sent to the distribution network transformer AVC substation for execution.

8. A reactive voltage compensation state evaluation device for a distribution network, characterized in that: The distribution network includes regional power main grids and regional power distribution networks at multiple voltage levels, including: A model building unit is used to build a global reactive power optimization model, wherein the global reactive power optimization model includes: a calculation model of capacitor reactors, a reactive power compensation model of centralized grid-connected new energy stations, and an analysis of the reactive power regulation capability of distributed new energy equipment of the regional power distribution network by an equivalent model, so as to form a main network reactive power optimization model including the regional power distribution network; A constraint condition acquisition unit, used for acquiring reactive power optimization constraint conditions, wherein the reactive power optimization constraint conditions include a distribution network bus voltage range, a line and transformer safety current range, a transformer on-load tap changer ratio range, and a reactive power supply output range; A reactive power optimization unit is used to input the real-time operating state of the distribution network into the global reactive power optimization model, and the global reactive power optimization model uses a cross approximation algorithm to perform global reactive power optimization calculations to obtain the current reactive voltage compensation state of the distribution network, wherein, in the process of performing the global reactive power optimization calculations, a sparse linear programming solution is used for the active power sub-problem, and an augmented Lagrangian function quadratic approximation solution is used for the reactive power sub-problem, so as to obtain an optimized power flow solution that satisfies the reactive power optimization constraint conditions; The reactive power compensation unit is used to output reactive power compensation configuration schemes for equipment at various levels and in various regions of the regional power grid main distribution network according to the current reactive power voltage compensation state.

9. An electronic device, characterized in that: It includes one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the reactive voltage compensation state assessment method for a distribution network as described in any one of claims 1 to 7.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method for evaluating the reactive voltage compensation state of a distribution network as described in any one of claims 1 to 7 are implemented.

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