Reactive voltage control method and device of power distribution network, electronic equipment and storage medium

Abstract

The invention discloses a reactive voltage control method and device for a power distribution network, electronic equipment and a storage medium, and relates to the field of power distribution network control, and the method comprises the steps: measuring the root node voltage of a 10kV bus in a predetermined coordination control region of the power distribution network, and according to the voltage optimization target value of the 10kV bus and the root node voltage, calculating the voltage optimization target value of the 10kV bus; the method comprises the following steps: calculating a feeder total reactive regulation variable of each distribution network feeder, determining an equivalent regulation generator model in a control region to construct a quadratic programming model, and performing reactive demand analysis on a distribution transformer district connected with each distribution network feeder by adopting the quadratic programming model based on the feeder total reactive regulation variable to obtain a reactive demand analysis result. And reactive power regulation data corresponding to each distribution network feeder participating in regulation is obtained, and reactive power voltage resources of the power distribution network are coordinated and controlled according to the reactive power regulation data. According to the invention, the technical problems of incapability of reactive power regulation, insufficient resource utilization, frequent action of equipment and influence on the service life of the equipment in the prior art are 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 reactive power voltage control method and device for a distribution network, an electronic device, and a storage medium. Background Art

[0002] In recent years, with the increasing global demand for renewable energy, especially the rapid growth of distributed photovoltaics, the reactive power voltage control of distribution networks has faced new challenges. The access of renewable energy such as distributed photovoltaics has changed the operating characteristics of traditional power grids, and the randomness and volatility of their output have had a significant impact on the voltage stability and reactive power balance of the power grid. In traditional power grids, voltage control mainly relies on reactive power regulation equipment in large power plants and substations, but the access of distributed photovoltaics has made the distribution of reactive power regulation resources more extensive in the distribution network. At the same time, due to the output characteristics of distributed power sources, traditional reactive power regulation strategies may no longer be applicable. Frequent voltage fluctuations and repeated regulation of reactive power equipment not only affect the power quality, but may also exacerbate equipment losses, reducing the operating efficiency and security of the power grid.

[0003] In related technologies, 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. At the same time, there is also insufficient utilization of reactive power regulation resources: often the reactive power regulation capabilities of renewable energy such as distributed photovoltaics are not fully utilized, which leads to relying mainly on conventional reactive power equipment when the output of renewable energy fluctuates, easily causing frequent operation of equipment and affecting the equipment life. And traditional reactive power voltage control modes are mostly single-level control in centralized or distributed forms, lacking coordinated control between upper and lower power grids and being difficult to achieve global optimization. Especially in the case of large fluctuations in the output of distributed photovoltaics, the limitations of a single control mode are more obvious.

[0004] In addition, in reactive power voltage control, single-objective optimization (such as minimizing system network losses, voltage stability, cost minimization, etc.) often leads to the sacrifice of other objectives. For example, when the voltage stability is the objective, it may not be possible to ensure the minimum system network losses at the same time. And multi-objective optimization methods such as the weighting method and the Pareto optimal solution set method are difficult to find an ideal compromise point in practical applications to achieve the optimal operation of the system as a whole.

[0005] In view of the above problems, no effective solution has been proposed yet. Summary of the Invention

[0006] An embodiment of the present invention provides a reactive power voltage control method and device for a distribution network, an electronic device, and a storage medium, so as to at least solve the technical problems in the related art that the utilization of reactive power regulation resources is insufficient, which easily causes frequent actions of equipment and affects the service life of the equipment.

[0007] To achieve the above object, according to one aspect of the present application, there is provided a reactive power voltage control method for a distribution network, including: measuring the root node voltage of the 10kV bus in a predetermined coordinated control area of the distribution network, where each 10kV bus is correspondingly connected to at least one distribution network feeder, and reactive power processing adjustment instructions have been pre-set on the distribution transformer substations of each of the distribution network feeders; calculating the total reactive power adjustment amount of each distribution network feeder according to the voltage optimization target value of the 10kV bus and the root node voltage; in the predetermined coordinated control area, determining each distribution transformer substation in each distribution network feeder as an equivalent adjustment generator model, and constructing a quadratic programming model based on the equivalent adjustment generator model and the reactive power adjustment capabilities of each distribution network feeder; based on the total reactive power adjustment amount of the feeder, using the quadratic programming model to perform reactive power demand analysis on the distribution transformer substations connected to each distribution network feeder, and obtaining reactive power adjustment data corresponding to each distribution network feeder participating in the adjustment, where the reactive power adjustment data includes: the reactive power adjustment amount, voltage adjustment amount, and voltage adjustment target value of each distribution transformer substation; coordinating and controlling the reactive power voltage resources of the distribution network according to the reactive power adjustment data, where the reactive power voltage resources include the reactive power of distributed photovoltaics and reactive power compensation devices.

[0008] Optionally, the step of calculating the total reactive power adjustment amount of each distribution network feeder according to the voltage optimization target value of the 10kV bus and the root node voltage includes: for each distribution network feeder, calculating the reactive power adjustment balance index of the distribution network feeder based on the current reactive power value of the distribution network feeder, the upper limit value and lower limit value of the reactive power adjustment of the distribution network feeder; inputting the root node voltage of the 10kV bus, the voltage optimization target value, the sensitivity of the injected reactive power of the 10kV bus to voltage, the reactive power adjustment balance index of the distribution network feeder, and the weight value of the corresponding reactive power balance target into the feeder reactive power adjustment model, and calculating the total reactive power adjustment amount of the distribution network feeder.

[0009] Optionally, the constraint conditions of the feeder reactive power adjustment model include: the voltage of the 10kV bus is within the limit range, and the reactive power adjustment ability of the distribution network feeder is within the adjustment ability range of the reactive power voltage resources in the distribution transformer substation.

[0010] Optionally, based on the total reactive power regulation amount of the feeder, the step of performing reactive power demand analysis on the distribution transformer substations of each distribution feeder by using the quadratic programming model to obtain the reactive power regulation data corresponding to each distribution feeder participating in the regulation includes: measuring the reactive power sensitivity of each distribution transformer substation to the root node of the distribution feeder, the current active power loss value of the distribution feeder area, and the sensitivity of the reactive power adjustment of each distribution transformer substation to the total active power loss in the distribution feeder area; inputting the current reactive power of the root node of the distribution feeder, the total reactive power regulation amount of the feeder, the reactive power sensitivity of the distribution transformer substation to the root node of the distribution feeder, the current active power loss value of the distribution feeder area, and the sensitivity of the reactive power adjustment of each distribution transformer substation to the total active power loss in the distribution feeder area into the quadratic programming model, and calculating to obtain the reactive power regulation data corresponding to each distribution feeder participating in the regulation.

[0011] Optionally, the constraint conditions of the quadratic programming model include: the voltage of the busbars of each distribution transformer substation in the distribution feeder area is within the limit range, and the reactive power regulation ability of the distribution transformer substation is within the regulation ability range of the reactive power and voltage resources of the distributed new energy it serves.

[0012] Optionally, the step of coordinately controlling the reactive power and voltage resources of the distribution network according to the reactive power regulation data includes: detecting the type of reactive power compensation demand of the superior substation corresponding to the distribution network; based on the demand type, switching on and off discrete reactive power devices during the period of load base change, where the discrete reactive power devices include in-station capacitors and reactors; and adjusting the reactive power and voltage resources of the distribution network itself during the period of load fluctuation.

[0013] Optionally, the step of coordinately controlling the reactive power and voltage resources of the distribution network according to the reactive power regulation data includes: when it is detected that the reactive power and voltage resources of the distribution network itself are exhausted, calculating the voltage coordination limit value of the 10 kV busbar; sending the voltage coordination limit value of the 10 kV busbar to the automatic voltage control system AVC of the superior substation corresponding to the distribution network, where the AVC completes the voltage regulation in the distribution network area by adjusting the reactive power devices in the superior substation.

[0014] According to another aspect of the embodiments of the present invention, there is also provided a reactive voltage control device for a distribution network, including: a voltage measurement unit for measuring the root node voltage of the 10 kV bus in a predetermined coordinated control area of the distribution network, wherein each 10 kV bus is correspondingly connected to at least one distribution network feeder, and reactive power processing and adjustment instructions have been preset on the distribution transformer substations of each of the distribution network feeders; a reactive power adjustment amount calculation unit for calculating the total reactive power adjustment amount of each distribution network feeder according to the voltage optimization target value of the 10 kV bus and the root node voltage; a planning model construction unit for determining each distribution transformer substation in each distribution network feeder as an equivalent adjustment generator model in the predetermined coordinated control area, and constructing a quadratic programming model based on the equivalent adjustment generator model and the reactive power adjustment capabilities of each distribution network feeder; a reactive power demand analysis unit for performing reactive power demand analysis on the distribution transformer substations connected to each distribution network feeder by using the quadratic programming model based on the total reactive power adjustment amount of the feeder, and obtaining reactive power adjustment data corresponding to each distribution network feeder participating in the adjustment, wherein the reactive power adjustment data includes: the reactive power adjustment amount, voltage adjustment amount and voltage adjustment target value of each distribution transformer substation; a resource coordination unit for coordinately controlling the reactive voltage resources of the distribution network according to the reactive power adjustment data, wherein the reactive voltage resources include the reactive power of distributed photovoltaic and reactive power compensation devices.

[0015] Optionally, the reactive power adjustment amount calculation unit includes: an index calculation module for calculating the reactive power adjustment balance index of each distribution network feeder based on the current reactive power value of the distribution network feeder, the upper limit value and the lower limit value of the reactive power adjustment of the distribution network feeder; a reactive power adjustment amount calculation module for inputting the root node voltage of the 10 kV bus, the voltage optimization target value, the sensitivity of the injected reactive power of the 10 kV bus to the voltage, the reactive power adjustment balance index of the distribution network feeder and the weight value of the corresponding reactive power balance target into the feeder reactive power adjustment model, and calculating the total reactive power adjustment amount of the distribution network feeder.

[0016] Optionally, the constraint conditions of the feeder reactive power adjustment model include: the voltage of the 10 kV bus is within the limit range, and the reactive power adjustment capability of the distribution network feeder is within the adjustment capability range of the reactive voltage resources in the distribution transformer substation.

[0017] Optionally, the reactive power demand analysis unit includes: a parameter measurement module configured to measure the reactive power sensitivity of each distribution transformer substation area to the root node of the distribution network feeder, the current active power loss value of the distribution network feeder area, and the sensitivity of the reactive power adjustment of each distribution transformer substation area to the total active power loss within the distribution network feeder area; a reactive power regulation data calculation module configured to input the current reactive power of the root node of the distribution network feeder, the total reactive power regulation amount of the feeder, the reactive power sensitivity of the distribution transformer substation area to the root node of the distribution network feeder, the current active power loss value of the distribution network feeder area, and the sensitivity of the reactive power adjustment of each distribution transformer substation area to the total active power loss within the distribution network feeder area into the quadratic programming model, and calculate the reactive power regulation data corresponding to each distribution network feeder participating in the regulation.

[0018] Optionally, the constraint conditions of the quadratic programming model include: the voltage of the busbars of each distribution transformer substation area within the distribution network feeder area is within the limit range, and the reactive power regulation ability of the distribution transformer substation area is within the regulation ability range of the reactive power and voltage resources of the distributed new energy it carries.

[0019] Optionally, the resource coordination unit includes: a demand type detection module configured to detect the demand type of the reactive power compensation of the superior substation corresponding to the distribution network; a device switching module configured to switch discrete reactive power devices during the load base change period based on the demand type, where the discrete reactive power devices include in-station capacitors and reactors; a resource regulation module configured to regulate the reactive power and voltage resources of the distribution network itself during the load fluctuation period.

[0020] Optionally, the resource coordination unit includes: a coordination limit calculation module configured to calculate the voltage coordination limit of the 10 kV busbar when it is detected that the reactive power and voltage resources of the distribution network itself are exhausted; a limit sending module configured to send the voltage coordination limit of the 10 kV busbar to the automatic voltage control system (AVC) of the superior substation corresponding to the distribution network, where the AVC completes the voltage regulation of the distribution network area by adjusting the reactive power devices in the superior substation.

[0021] According to another aspect of the embodiments of the present invention, there is also provided a computer-readable storage medium, where the computer-readable storage medium includes a stored computer program, and when the computer program runs, it controls the device where the computer-readable storage medium is located to execute the reactive power and voltage control method of the distribution network according to any one of the above.

[0022] 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, where the memory is used to store one or more programs, and 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 power and voltage control method of the distribution network according to any one of the above.

[0023] According to another aspect of the embodiments of the present invention, there is also provided a computer program product, including a computer program, and when the computer program is executed by a processor, it implements the steps of the reactive voltage control method of the distribution network described in any one of the above.

[0024] In the present disclosure, the root node voltage of the 10 kV bus in a predetermined coordinated control area of the distribution network is measured. Each 10 kV bus is correspondingly connected to at least one distribution network feeder, and reactive power processing adjustment instructions have been preset on the distribution transformer substations of each distribution network feeder; according to the voltage optimization target value of the 10 kV bus and the root node voltage, the total reactive power adjustment amount of each distribution network feeder is calculated; in the predetermined coordinated control area, each distribution transformer substation in each distribution network feeder is determined as an equivalent adjustment generator model, and based on the equivalent adjustment generator model and the reactive power adjustment capabilities of each distribution network feeder, a quadratic programming model is constructed; based on the total reactive power adjustment amount of the feeder, the quadratic programming model is used to perform reactive power demand analysis on the distribution transformer substations connected to each distribution network feeder, and the reactive power adjustment data corresponding to each distribution network feeder participating in the adjustment is obtained. The reactive power adjustment data includes: the reactive power adjustment amount, voltage adjustment amount, and voltage adjustment target value of each distribution transformer substation; according to the reactive power adjustment data, the reactive voltage resources of the distribution network are coordinately controlled, where the reactive voltage resources include the reactive power of distributed photovoltaics and reactive power compensation devices.

[0025] In the present disclosure, by using the quadratic programming model to perform reactive power demand analysis on the distribution transformer substations connected to each distribution network feeder, the reactive power adjustment data corresponding to each distribution network feeder participating in the adjustment is obtained, and the reactive voltage resources of the distribution network are coordinately controlled, so as to fully mobilize the reactive power adjustment potential in the distribution network. Combined with the adjustment of conventional reactive power compensation devices (such as capacitors and reactors), the optimal allocation of reactive power resources is realized. It can not only reduce the frequent operation of reactive power equipment, reduce equipment losses, but also improve the overall operation efficiency of the system, thus solving the technical problems in the related art that the utilization of reactive power adjustment resources is insufficient, which easily causes frequent operation of equipment and affects the service life of equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present invention, and constitute 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:

[0027] Figure 1 is a flowchart of an optional reactive voltage control method for a distribution network according to an embodiment of the present invention;

[0028] Figure 2 is a schematic diagram of a calculation model for the first-stage decision-making of AVC for a distribution network according to an embodiment of the present invention;

[0029] Figure 3 It is a schematic diagram of a calculation model for the second-stage decision-making of the AVC of a distribution network according to an embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of the voltage coordinated control of a distribution network and a transmission network according to an embodiment of the present invention;

[0031] Figure 5 It is a schematic diagram of a reactive power voltage control device for a distribution network according to an embodiment of the present invention;

[0032] Figure 6 It is a block diagram of the structure of an electronic device according to an embodiment of the present application. Detailed implementation manners

[0033] 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.

[0034] 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 other than those illustrated or described herein. In addition, the terms "comprising" and "having" 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 need 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.

[0035] To facilitate the understanding of the present invention by those skilled in the art, the following explains some terms or nouns involved in each embodiment of the present invention:

[0036] AVC, Automatic Voltage Control, the automatic voltage control system, which is mainly used for the automatic control of voltage, is an automation control technology that can monitor the voltage status of the power grid in real time and automatically adjust the reactive power distribution to maintain the voltage within the specified range. In the distribution network of this embodiment, the AVC system realizes the stable control of voltage by automatically controlling the reactive power compensation devices (such as capacitors, reactors, and static var generators SVG, etc.) in the substation and adjusting the reactive power of distributed power sources (such as photovoltaic and wind power). The AVC system can quickly respond to voltage changes according to the real-time power grid status, adjust reactive power resources, thus avoiding voltage over-limit, improving power quality, reducing the frequent operation of reactive power equipment, and prolonging the equipment life.

[0037] EMS, Energy Management System, is a comprehensive automation system used for the dispatching center to monitor and optimize the management of the power system in real time. At the distribution network level of this embodiment, the EMS system is mainly responsible for tasks such as data acquisition, state estimation, load management, fault detection and isolation, etc., to ensure the stable operation and efficient dispatching of the distribution network. The EMS system can collect real-time data in the power grid, such as bus voltage, line current, power factor, etc., and through analysis and processing, provide decision-making support for dispatchers, and can also automatically execute some preset control strategies, such as load transfer, fault recovery, etc.

[0038] The following embodiments of the present invention can be applied to systems / applications / devices for reactive voltage control of various distribution networks. The present invention proposes a method and system for reactive voltage control of a distribution network considering distributed photovoltaics, aiming to achieve refined control of the reactive voltage of the distribution network through two-stage decision analysis, make full use of the reactive power regulation ability of renewable energy such as distributed photovoltaics, reduce the frequent operation of substation reactive power equipment, and at the same time, through the coordinated control of reactive power and voltage between the upper and lower levels, maintain the voltage stability of the distribution network, and optimize the overall operation efficiency and economy of the power system.

[0039] In the present invention, the reactive power control decision-making for the 10 kV distribution network is carried out in two stages. The first stage is the reactive power control decision analysis for the 10 kV feeder, and the second stage is the reactive power control decision analysis for the distribution transformer area. Then, the coordinated control of reactive power between the upper and lower levels of the substation and the distribution network reactive voltage control system is carried out, and finally, the coordinated control of the substation and the distribution network voltage system to the lower-level voltage is carried out.

[0040] Among them, the first stage decision analysis: taking the voltage optimization value of the 10kV bus as the target, using the global reactive power optimization strategy of the regional power grid main distribution coordination, calculate the reactive power regulation strategy of each 10kV feeder to ensure the reasonable allocation of reactive power regulation resources under the voltage optimization target. The second stage decision analysis: taking the constructed 10kV feeder coordinated control area as the object, based on the total reactive power setting value of the feeder area root node calculated in the first stage, calculate the reactive power regulation instructions of the adjustable distributed renewable energy in the 10kV feeder coordinated control area, so that the reactive power regulation of the substation area is coordinated with the voltage optimization target, while considering reducing the active network loss in the 10kV feeder area.

[0041] Coordinated control of upper and lower reactive power: Through the interaction between the substation AVC and the distribution network AVC, the coordinated control of discrete reactive equipment such as the substation 10kV busbar capacitor and the distributed new energy reactive equipment of the distribution network is realized, the irrational flow of reactive equipment is reduced, and the economy and stability of the system operation are improved. Coordinated control of upper and lower voltage means that when the reactive power regulation capacity in the distribution network area is insufficient and the voltage in the substation area is too high or too low to exceed the limit, the distribution network AVC sends the voltage regulation demand to the ground-adjusting AVC in real time. The ground-adjusting AVC realizes auxiliary regulation of the distribution network voltage by controlling the reactive equipment in the substation to ensure stable voltage control.

[0042] The present invention is described in detail below in conjunction with various embodiments.

[0043] Embodiment 1

[0044] According to an embodiment of the present invention, an embodiment of a reactive voltage control method for 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.

[0045] Figure 1 is a flow chart of an optional reactive voltage control method for a distribution network according to an embodiment of the present invention, such as Figure 1 As shown, the method comprises the following steps:

[0046] Step S101, measuring the root node voltage of a 10kV bus in a predetermined coordinated control area of ​​a distribution network, wherein each 10kV bus is connected to at least one distribution network feeder, and reactive power processing adjustment instructions are pre-set on the distribution transformer area of ​​each distribution network feeder.

[0047] In the operation and control of the distribution network, the predetermined coordinated control area of the distribution network refers to a control unit composed of a series of 10kV busbars and the distribution network feeders connected thereto. Each 10kV busbar is connected to at least one distribution network feeder, and the set of these feeders constitutes a coordinated control area. The purpose of measuring the root node voltage of these 10kV busbars is to evaluate the current voltage level and compare it with the preset voltage optimization target value, so as to determine whether reactive power regulation is required, as well as the direction and magnitude of the regulation.

[0048] Reactive power processing and regulation instructions have been preset on the distribution transformer substations of each distribution network feeder. This means that the distribution network AVC system has preset regulation strategies for the reactive power regulation equipment (such as distributed photovoltaics, energy storage batteries, capacitors, etc.) in each distribution transformer substation, including the upper and lower limits of the available reactive power of the equipment, the current reactive power state, and the reactive power regulation instructions, enabling the system to quickly respond to voltage changes and adjust the reactive power.

[0049] Optionally, the step of calculating the total feeder reactive power regulation amount of each distribution network feeder according to the voltage optimization target value of the 10kV busbar and the root node voltage includes: for each distribution network feeder, calculating the reactive power adjustment balance index of the distribution network feeder based on the current reactive power value of the distribution network feeder, the upper limit value and the lower limit value of the reactive power adjustment of the distribution network feeder; inputting the root node voltage of the 10kV busbar, the voltage optimization target value, the sensitivity of the injected reactive power of the 10kV busbar to voltage, the reactive power adjustment balance index of the distribution network feeder, and the weight value of the corresponding reactive power balance target into the feeder reactive power regulation model, and calculating the total feeder reactive power regulation amount of the distribution network feeder.

[0050] In the process of calculating the total feeder reactive power regulation amount, first calculate the reactive power adjustment balance index for each distribution network feeder. This index takes into account the current reactive power state of the feeder and the balance degree of its regulation ability, so as to evaluate the potential and efficiency of the feeder to regulate reactive power. Input the root node voltage of the 10kV busbar, the voltage optimization target value, the sensitivity of the injected reactive power of the 10kV busbar to voltage, the reactive power adjustment balance index of the feeder, and the weight value of the corresponding reactive power balance target into the feeder reactive power regulation model, and calculate the total feeder reactive power regulation amount. The feeder reactive power regulation model here is a quadratic programming model, which gives priority to the voltage optimization target, and at the same time considers the balanced distribution of reactive power and the impact of regulation on other system objectives (such as economy, stability). In the model, the setting of the weight value determines the relative importance of the voltage target and the reactive power balance target in the control strategy. Usually, the voltage control has a higher priority than the reactive power balance.

[0051] Optionally, the constraint conditions of the feeder reactive power regulation model include: the voltage of the 10kV busbar is within the limit range, and the reactive power regulation ability of the distribution network feeder is within the regulation ability range of the reactive power and voltage resources in the distribution transformer substation area.

[0052] It should be noted that the constraint conditions of the feeder reactive power regulation model in this embodiment are the basis for ensuring the feasibility and safety of the optimization scheme in the actual power grid operation. The constraint conditions mainly include: The voltage of the 10kV bus is within the limit range: This is the basic requirement for reactive power optimization, ensuring that the adjusted voltage level does not exceed the upper and lower voltage limits specified by the power system operation standard, so as to maintain the voltage quality and stability of the power grid. The reactive power regulation ability of the distribution network feeder is within the regulation ability range of the reactive voltage resources in the distribution transformer substation area: This ensures that the execution of the reactive power regulation command will not cause the reactive power equipment in the distribution transformer substation area or on the feeder to exceed the upper and lower limits of its regulation ability, avoiding equipment overload or abnormal operation, and thus ensuring the equipment safety and system stability during the reactive power optimization process.

[0053] Step S102, calculate the total reactive power regulation amount of each distribution network feeder according to the voltage optimization target value of the 10kV bus and the root node voltage.

[0054] Through precise reactive power regulation strategies, the voltage optimization target is achieved, while ensuring the safe and economic operation of the power grid. Among them, the voltage optimization target value is the ideal value that the 10kV bus voltage should reach, which is preset according to the overall operation status and requirements of the distribution network. The selection of the target value is usually based on the results of global reactive power optimization, considering factors such as the voltage quality, economy, and stability of the power grid to improve the operation efficiency of the distribution network.

[0055] The root node voltage refers to the current voltage of a specific 10kV bus in the distribution network, that is, the actual value of the voltage measurement. The root node voltage is a direct reflection of the system state, used to evaluate the deviation from the voltage optimization target value, so as to guide the calculation of the reactive power regulation amount. For the calculated total reactive power regulation amount, it refers to the total amount of reactive power that each distribution network feeder needs to adjust in order to achieve the voltage optimization target. This is not just a simple increase or decrease of reactive power, but the most appropriate regulation amount calculated through an optimization model according to the reactive power regulation ability of the feeder and the overall demand of the power grid.

[0056] Specifically, the system first obtains the current voltage (root node voltage) of the 10 kV bus, the active power, reactive power of the distribution network feeder, and the reactive power regulation capacity data of each feeder, including the reactive power upper limit and reactive power lower limit, from the AVC substation of the distribution network. Then, it calculates the reactive power adjustment balance index: for each distribution network feeder, the reactive power adjustment balance index of the feeder is calculated through its current reactive power injection value and regulation capacity range to ensure the balanced distribution of reactive power regulation among different feeders and prevent equipment losses or voltage quality problems caused by excessive regulation of some feeders. After that, the root node voltage of the 10 kV bus, the voltage optimization target value, the sensitivity of the reactive power injected into the 10 kV bus to the voltage, as well as the reactive power adjustment amount of the feeder, the reactive power adjustment balance index, and the corresponding reactive power and voltage target weight values are input into the quadratic programming model together. By solving the quadratic programming model, the system obtains the total reactive power regulation amount of each distribution network feeder. Then, based on the calculation results, the system performs reactive power adjustment on the distribution network feeder to achieve the voltage optimization target. The constraint conditions that need to be satisfied in this process include:

[0057] Step S103: In a predetermined coordinated control area, each distribution transformer substation area in each distribution network feeder is determined as an equivalent regulated generator model, and a quadratic programming model is constructed based on the equivalent regulated generator model and the reactive power regulation capacity of each distribution network feeder.

[0058] In step S103, the reactive power-voltage control is further refined by regarding the distribution transformer substation area as an equivalent regulated generator model. Among them, the equivalent regulated generator model is essentially an idealized expression used to simulate the behavior and role of the distribution transformer substation area and the distributed energy sources (such as distributed photovoltaic, energy storage devices, etc.) it serves in reactive power regulation. Through the construction of this model, the complex reactive power regulation characteristics of the distribution transformer substation area can be simplified into an easily understandable and controllable form and then integrated into the quadratic programming model for unified optimization calculation.

[0059] When constructing the equivalent regulated generator model, it is based on the following key elements: Distribution transformer substation area parameters: including the rated voltage, rated power of the distribution transformer substation area, and the reactive power regulation capacity of the distributed energy sources connected to it (such as the reactive power that can be increased, the reactive power that can be decreased, the reactive power upper limit, the reactive power lower limit, etc.). Sensitivity analysis: By analyzing the influence degree of the reactive power injected by the distribution transformer substation area on the reactive power of the feeder root node and the sensitivity of the reactive power adjustment of the distribution transformer substation area to the total active power loss of the area, the benefits and impacts of the reactive power regulation instructions are determined. State variables: The current active and reactive power outputs of the distribution transformer substation area (current reactive power output), as well as other state information related to the distribution transformer substation area, such as temperature, load factor, etc. Although these may not be directly used in the optimization model, in practical applications, they are important references for system decision-making.

[0060] When constructing a quadratic programming model, not only the mathematical form of the model needs to be considered, but also its adaptability and stability in the actual power grid environment should be focused on. For example, the sensitivity parameters used in the model should be based on the latest power flow calculation results of the power grid to reflect the real state of the power grid. In addition, the reactive power regulation capabilities (upper and lower limits) of distribution transformer substations should be updated regularly to adapt to the changes in the output of distributed energy. The solution result of the quadratic programming model, that is, the reactive power regulation instruction, should be able to be fed back to the corresponding distribution transformer substation equipment in real time for rapid execution. At the same time, considering the dynamic changes in the operating conditions of the distribution network, the quadratic programming model should have the ability of online recalculation, that is, it should be able to re-solve the model, adjust the reactive power regulation strategy when the power grid state changes, so as to continuously optimize the voltage and reduce the network loss.

[0061] Step S104: Based on the total reactive power regulation amount of the feeder, use the quadratic programming model to analyze the reactive power demand of the distribution transformer substations connected to each distribution network feeder, and obtain the reactive power regulation data corresponding to each distribution network feeder participating in the regulation. Among them, the reactive power regulation data includes: the reactive power adjustment amount, voltage adjustment amount and voltage adjustment target value of each distribution transformer substation.

[0062] Optionally, the step of using the quadratic programming model to analyze the reactive power demand of the distribution transformer substations of each distribution network feeder based on the total reactive power regulation amount of the feeder and obtaining the reactive power regulation data corresponding to each distribution network feeder participating in the regulation includes: measuring the reactive power sensitivity of each distribution transformer substation to the root node of the distribution network feeder, the current active power network loss value in the distribution network feeder area, and the sensitivity of the reactive power adjustment of each distribution transformer substation to the total active power network loss in the distribution network feeder area; inputting the current reactive power of the root node of the distribution network feeder, the total reactive power regulation amount of the feeder, the reactive power sensitivity of the distribution transformer substation to the root node of the distribution network feeder, the current active power network loss value in the distribution network feeder area, and the sensitivity of the reactive power adjustment of each distribution transformer substation to the total active power network loss in the distribution network feeder area into the quadratic programming model, and calculating to obtain the reactive power regulation data corresponding to each distribution network feeder participating in the regulation.

[0063] Before performing the reactive power demand analysis, it is necessary to measure the reactive power sensitivity of each distribution transformer substation to the root node of the distribution network feeder, which reflects the influence degree of increasing or decreasing the reactive power on the reactive power of the feeder root node at the distribution transformer substation. At the same time, obtain the current active power network loss value in the distribution network feeder area and the sensitivity of the reactive power adjustment of each distribution transformer substation to the total active power network loss in the distribution network feeder area, which will help the system evaluate the influence of different reactive power regulation strategies on the active power network loss and achieve economic optimization.

[0064] Take the above measurement results, together with the current reactive power of the root node of the distribution network feeder, the total reactive power regulation amount of the feeder, the reactive power sensitivity of the distribution transformer substation area to the root node of the distribution network feeder, the current active power loss value of the distribution network feeder area, and the sensitivity of the reactive power adjustment of each distribution transformer substation area to the total active power loss in the distribution network feeder area, as input parameters and incorporate them into the quadratic programming model. The quadratic programming model is an efficient optimization tool that can handle multi-variable and multi-objective optimization problems. By solving the quadratic objective function and linear constraint conditions, the optimal reactive power regulation strategy can be found.

[0065] Among them, the optimization objective of the quadratic programming model is usually to minimize the total active power loss value in the distribution network feeder area while ensuring that the voltages of all distribution transformer substations participating in the regulation are within the qualified range. Through model solving, the reactive power regulation data corresponding to each distribution network feeder participating in the regulation can be obtained, including the reactive power amount that needs to be increased or decreased, and the specific reactive power regulation instructions, which are used to guide the optimization regulation of the reactive power resources of the distribution transformer substations.

[0066] Optionally, the constraint conditions of the quadratic programming model include: the voltages of the buses of each distribution transformer substation in the distribution network feeder area are within the limit range, and the reactive power regulation ability of the distribution transformer substation is within the regulation ability range of the reactive power and voltage resources of the distributed new energy it carries.

[0067] It should be noted that the constraint conditions of the quadratic programming model ensure the feasibility and safety of the optimization scheme in practical applications. Among them, the voltages of the buses of each distribution transformer substation in the distribution network feeder area are within the limit range: this constraint condition ensures that the adjusted voltage level will not exceed the upper and lower voltage limits specified by the power system operation standard, avoiding the impact of voltage over-limit on the grid stability and power quality. The reactive power regulation ability of the distribution transformer substation is within the regulation ability range of the reactive power and voltage resources of the distributed new energy it carries: this means that the reactive power regulation instructions must consider the actual reactive power regulation ability of the distributed new energy (such as photovoltaic, energy storage, etc.) in the distribution transformer substation, avoiding exceeding the equipment regulation range and causing equipment overload or regulation failure. Through the solution of the quadratic programming model, the system can realize the intelligent control of the reactive power and voltage of the distribution network, not only optimizing the voltage quality and reducing the active power loss, but also taking into account the safe operation and economy of the grid equipment.

[0068] Step S105, coordinate and control the reactive power and voltage resources of the distribution network according to the reactive power regulation data, where the reactive power and voltage resources include the reactive power of the distributed photovoltaic and the reactive power compensation equipment.

[0069] Optionally, the steps of coordinately controlling the reactive power and voltage resources of the distribution network according to the reactive power regulation data include: detecting the type of reactive power compensation required by the superior substation corresponding to the distribution network; based on the type of demand, switching discrete reactive power devices during the period of basic load change, where the discrete reactive power devices include in-station capacitors and reactors; and adjusting the reactive power and voltage resources of the distribution network itself during the period of load fluctuation.

[0070] During the period of basic load change, that is, the period when the grid load shows regular and predictable changes, the technical solution gives priority to switching discrete reactive power devices, such as in-station capacitors, reactors, etc. The switching of these devices can quickly respond to load changes and provide the required reactive power, thus maintaining the stability of the 10kV bus voltage. The control strategy of discrete reactive power devices is based on the detection of the reactive power compensation demand of the superior substation, that is, the system judges its reactive power compensation demand for the distribution network by real-time monitoring of the operation data of the superior substation. If the demand type is "basic compensation", then during the period of basic load change, the system will selectively switch capacitors or reactors according to the reactive power regulation data to meet the reactive power demand of the superior substation, while ensuring the economy and voltage quality of the distribution network operation.

[0071] When entering the period of load fluctuation, that is, when the load change is random and unpredictable, the technical solution will give priority to using the reactive power regulation resources of the distribution network itself, such as distributed photovoltaic, energy storage batteries, conventional capacitors, etc. connected to the low-voltage side of the distribution transformer. This is because the reactive power regulation ability of distributed energy can quickly respond to short-term load fluctuations, and its regulation has a more delicate impact on the voltage of the distribution network, avoiding the equipment loss and increased operation cost that may be brought by the repeated operation of discrete reactive power devices. During this period, the system analyzes the reactive power demand and resource availability by real-time monitoring of the operation state of the distribution network, and automatically adjusts the reactive power injection amount of the above resources to meet the voltage control target and reduce the active power loss.

[0072] Optionally, the steps of coordinately controlling the reactive power and voltage resources of the distribution network according to the reactive power regulation data include: when it is detected that the reactive power and voltage resources of the distribution network itself are exhausted, calculating the voltage coordination limit of the 10kV bus; sending the voltage coordination limit of the 10kV bus to the automatic voltage control system AVC of the superior substation corresponding to the distribution network, where the AVC completes the voltage regulation in the distribution network area by adjusting the reactive power devices in the superior substation.

[0073] When it is detected that the reactive power regulation capacity of the distribution network is insufficient, the system will calculate the voltage coordination limit of the 10kV bus in real time according to the current reactive power regulation data and the grid operation status. This limit is the voltage change range required to maintain voltage stability under the current limit of reactive power regulation capacity of the system. It clearly defines, in a quantified manner, how the upstream substation should adjust its reactive power equipment when the reactive power resources in the distribution network are exhausted to assist the distribution network in voltage control.

[0074] The calculated voltage coordination limit will be immediately sent to the Automatic Voltage Control (AVC) system of the upstream substation corresponding to the distribution network. After receiving the limit, the AVC system will adjust the operating status of the reactive power equipment in the substation according to this information, such as increasing the operation of capacitors and reducing the operation of reactors, to provide additional reactive power and assist the distribution network in overcoming the limitations of its reactive power resources and achieving stable voltage control. The implementation of this strategy not only solves the bottleneck problem of the reactive power regulation capacity of the distribution network under specific conditions, but also optimizes the reactive power voltage regulation strategy of the entire power grid through coordinated control between the upstream and downstream substations, improving the overall operation efficiency and stability of the system.

[0075] Through the above steps, the root node voltage of the 10kV bus in the predetermined coordinated control area of the distribution network can be measured. Among them, each 10kV bus is correspondingly connected to at least one distribution network feeder, and reactive power processing and regulation instructions have been preset on the distribution transformer platforms of each distribution network feeder; according to the voltage optimization target value of the 10kV bus and the root node voltage, calculate the total reactive power regulation amount of each distribution network feeder; in the predetermined coordinated control area, determine each distribution transformer platform in each distribution network feeder as an equivalent regulated generator model, and construct a quadratic programming model based on the equivalent regulated generator model and the reactive power regulation capacity of each distribution network feeder; based on the total reactive power regulation amount of the feeder, use the quadratic programming model to analyze the reactive power demand of the distribution transformer platforms connected to each distribution network feeder, and obtain the reactive power regulation data corresponding to each distribution network feeder participating in the regulation. Among them, the reactive power regulation data includes: the reactive power adjustment amount, voltage adjustment amount and voltage adjustment target value of each distribution transformer platform; according to the reactive power regulation data, coordinate and control the reactive power and voltage resources of the distribution network, where the reactive power and voltage resources include the reactive power of distributed photovoltaics and reactive power compensation equipment. In this embodiment, by using the quadratic programming model to analyze the reactive power demand of the distribution transformer platforms connected to each distribution network feeder, the reactive power regulation data corresponding to each distribution network feeder participating in the regulation can be obtained, and the reactive power and voltage resources of the distribution network can be coordinated and controlled, so as to fully mobilize the reactive power regulation potential in the distribution network, combined with the regulation of conventional reactive power compensation equipment (such as capacitors and reactors), to achieve the optimal allocation of reactive power resources. It can not only reduce the frequent operation of reactive power equipment, reduce equipment losses, but also improve the overall operation efficiency of the system, thus solving the technical problems in the related art that the reactive power regulation resources cannot be fully utilized, easily cause frequent operation of equipment, and affect the equipment life.

[0076] The following is a detailed description in combination with another optional specific implementation manner.

[0077] In this implementation manner, first, the reactive power control decision analysis of the 10 kV distribution network is carried out, which mainly includes two stages. The first stage is the reactive power control decision analysis of the 10 kV feeder, and the second stage is the reactive power control decision analysis of the transformer substation area. Then, the up-down reactive power coordinated control of the substation and the distribution network reactive power voltage control system is carried out. Finally, the substation and the distribution network voltage system carry out the down-level voltage coordinated control.

[0078] At the distribution network level of the regional power grid, a two-stage main-distribution network voltage coordinated control decision method based on the global reactive power optimization target is adopted to realize the voltage coordinated control of the main network and the distribution network. First, the first-stage decision is carried out. In the distribution network AVC, taking the optimized value of the 10 kV bus voltage of the substation given by the global reactive power optimization of the main-distribution coordination of the regional power grid as the target value, and taking the reactive power regulation capabilities of each 10 kV feeder sent by the distribution network AVC as the adjustment means, the reactive power regulation strategies of each 10 kV feeder are calculated. Secondly, the second-stage decision is carried out. In the distribution network AVC, 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 dispatching AVC as the target, and taking the voltage qualification of each load transformer substation as the constraint condition, the reactive power regulation instructions of the adjustable distributed new energy within the 10 kV feeder coordinated control area are calculated and sent to the transformer substation AVC substation for execution.

[0079] In terms of the coordinated control of the reactive power voltage of the regional main network and the distribution network, 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 action times of the reactive power equipment in the substation. A multi-time dimension reactive power optimization method is adopted. Through day-ahead and intra-day rolling reactive power optimization, when 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 itself 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 ability of the distribution network itself is insufficient. An online calculation method of the main-distribution coordination limit constraint is adopted. When the reactive power resources within the 10 kV feeder coordinated control area are exhausted, the coordination limit of the root node voltage is calculated in real time and sent to the dispatching AVC, and the dispatching AVC assists in voltage regulation by adjusting the reactive power equipment in the substation.

[0080] First-stage decision: Reactive power control decision of the 10 kV feeder. Among them, the model object of the first-stage decision is the 10 kV bus coordinated control area in the regional distribution network, that is, the 10 kV feeder carried by the 10 kV bus (including the parallel bus) on the low-voltage side of the 110 kV and 35 kV substations in the regional power grid. The main objects in the model are given in Figure 2 are given.

[0081] Figure 2 The left part in the figure shows the composition of the calculation model for the first-stage decision-making. In the first-stage decision-making summary, the control objective is the optimized voltage value Vopf of the 10 kV bus. On the one hand, this value ensures that it is within the preset upper and lower voltage limits. On the other hand, it adopts the optimized bus voltage target value given by the global reactive power optimization calculation of the main and distribution coordination of the regional power grid. The control object of the decision is the reactive power of the 10 kV feeder(s) with reactive power regulation capabilities connected to this 10 kV bus (including the parallel operating buses). Each control object corresponds to a 10 kV feeder coordinated control area. The area includes 1 independently operating feeder, or several parallel operating feeders. Each area includes the load objects of the substations carried by the 10 kV feeder, as well as the adjustable reactive power resources such as distributed photovoltaics and energy storage carried by the substations, such as Figure 2 shown on the right side. The current active and reactive power outputs of the 10 kV feeder(s) can be obtained in the local dispatching EMS (Local Dispatching Energy Management System). Its current reactive power regulation capabilities that can be increased and decreased are received by the distribution network AVC (Automatic Voltage Control) from the reactive power regulation capabilities of each AVC substation and aggregated to the feeder(s) object, and the current reactive power upper limit value Qmax and reactive power lower limit value Qmin are determined. The connection between the control object and the control target is reflected by the sensitivity Cv, that is, the change in the 10 kV bus voltage after injecting reactive power into this 10 kV bus.

[0082] Taking Figure 2 the distribution network feeder(s) carried by the 10 kV bus of the regional power grid shown as an object, the following second-level programming model is constructed:

[0083] The optimization objective is:

[0084]

[0085] Among them, V j is the current value of the voltage of the 10 kV bus j, is the optimized target value of the voltage of the 10 kV bus j, which is the optimized bus voltage target given by the global reactive power optimization calculation of the main and distribution coordination of the regional power grid. Ω i is the set of 10 kV feeder(s) connected to the 10 kV bus j, ΔQ i is the reactive power adjustment amount of the 10 kV feeder i to be calculated; C vj is the sensitivity of injecting reactive power into the 10 kV bus j to the voltage, is the reactive power adjustment balance index of the i-th 10 kV feeder, and its definition is:

[0086]

[0087] Among them, Q i is the current reactive power injection value of the 10 kV feeder (group) i, is the upper limit and lower limit of reactive power adjustment of the 10 kV feeder (group). After the distribution network AVC receives the reactive power regulation capabilities sent by the sub-stations of the district AVC and calculates and aggregates them to the feeder (group).

[0088] In formula (1), W v and W q are the weights of the voltage target and the reactive power balance target respectively. With the voltage target being prioritized, generally take W v = 1.0, W q = 0.1.

[0089] The constraint conditions that the optimization model of formula (1) needs to satisfy are:

[0090]

[0091] Among them, formula (3) indicates that the voltage of the 10 kV bus is within the limit range, and formula (4) indicates that the reactive power regulation capability of the 10 kV feeder (group) is within the regulation capability range of the reactive power resources in the districts it serves.

[0092] The second-stage decision: the reactive power control decision of the district. It should be noted that the object of calculation in the second-stage decision is the 10 kV feeder (group), that is, the 10 kV feeder coordinated control area, which includes each transformer on the 10 kV feeder and the distributed power sources connected to the low-voltage side of the transformer. The calculation model is as Figure 3 shown.

[0093] Figure 3 The left side in shows the composition of the calculation model of the second-stage decision. In the second-stage decision, the control target is the reactive power setting value Ql ineset of the 10 kV feeder, which is given by the first-stage decision; the control object is the reactive power injection of each 10 kV transformer. The calculation object of the second stage is the 10 kV feeder coordinated control area proposed in Research Content 1. Each area includes one or more parallel-running 10 kV feeders and the transformer loads they serve. The reactive power resources mainly consider distributed photovoltaic power generation, energy storage batteries, and conventional capacitors connected to the low-voltage side of the transformer, as Figure 3 shown on the right side. The control object of the decision is the reactive power output of each 10 kV transformer (group).

[0094] The current active and reactive power outputs of the 10 kV feeder (group) can be obtained from the local dispatching EMS. The current reactive power output Qnd of each transformer substation (group), as well as the reactive power regulation capacity, i.e., the reactive power upper limit Qmax and the reactive power lower limit Qmin, are calculated and uploaded in real time by the substation AVC system. The relationship between the control object and the control target is reflected by the sensitivity Cq, that is, the change in the total reactive power at the root node of the feeder (group) after injecting reactive power into transformer substation i. This sensitivity value can be obtained through the power flow calculation of the transmission and distribution network proposed in Research Content 1.

[0095] Meanwhile, in the second-stage decision-making, the decision-making goal also considers reducing the active power loss in the 10 kV feeder area. By solving the sensitivity Cl of the active power loss of the 10 kV feeder (group) to the reactive power injection of the transformer substation, the influence index of the reactive power regulation of the transformer substation area on the active power loss of the 10 kV feeder group can be obtained, so as to realize reducing the power loss through the reactive power regulation of the transformer substation area.

[0096] Taking Figure 3 the distribution network feeder (group) powered by the 10 kV bus of the regional power grid shown as the object, the following two-stage programming model is constructed:

[0097] The optimization goal is:

[0098]

[0099] Among them, is the current value of the reactive power at the root node of the 10 kV feeder, is the control target value of the reactive power at the root node of the 10 kV feeder, which is calculated and given by the first-stage decision-making. Ω i is the set of 10 kV transformer substations connected to the 10 kV feeder area j, ΔQ i is the adjustment amount of the reactive power injection of transformer substation i to be calculated; C qi is the sensitivity of the reactive power injected by the 10 kV transformer substation j to the reactive power at the root node of the 10 kV feeder, is the current active power loss value of the 10 kV feeder group area, C li is the sensitivity of the reactive power adjustment of the i-th 10 kV transformer substation to the total active power loss in the 10 kV feeder area.

[0100] In formula (5), W q and W l are the weights of the voltage target and the reactive power balance target respectively. With the voltage target being prioritized, generally take W q = 1.0, W l = 0.1.

[0101] The constraint conditions that the optimization model of formula (5) needs to satisfy are:

[0102]

[0103] Among them, Equation (6) indicates that within the 10 kV feeder area, the voltage requirements of the busbars of each 10 kV substation transformer should be within the limit range. In this constraint condition, k represents the substation transformers in this 10 kV feeder area, including those connected to distributed new energy and having reactive power condition capabilities, as well as ordinary substation transformers with voltage measurement capabilities. Among them, C vi,k represents the sensitivity of injecting reactive power on the i-th substation transformer to the voltage of the k-th other substation transformer in the area. Equation (7) indicates that the reactive power regulation ability of the 10 kV substation transformer is within the total regulation ability range of the reactive power resources of the distributed new energy it serves.

[0104] Superior-subordinate coordinated control of substation AVC and distribution network AVC: Since the voltage control objectives of substation AVC and distribution network AVC are both the bus voltage optimization objectives given by the reactive power voltage optimization of the main and distribution coordination of the regional power grid, their overall control directions are the same. In order to further achieve the refined coordination of substation AVC and distribution network AVC, it is necessary to consider from two aspects: superior-subordinate reactive power coordination and superior-subordinate voltage coordination.

[0105] In terms of the superior-subordinate reactive power coordination of substation AVC and distribution network AVC, it is mainly to coordinately control discrete reactive power devices such as capacitors on the 10 kV busbar of the substation, as well as reactive power devices such as distribution network distributed new energy served by the 10 kV feeder, and reduce the unreasonable flow of reactive power while ensuring qualified voltage and optimization. The principle of coordinated control is:

[0106] 1) Capacitor reactors are used as basic reactive power compensation. For large-capacity basic reactive power demands, switching is preferentially performed.

[0107] 2) The distribution network distributed new energy served by the 10 kV feeder should give full play to its role, be preferentially adjusted when the new energy power generation fluctuates, and reduce the switching of capacitors.

[0108] In order to implement this coordination principle, the key to coordination is to correctly determine whether the reactive power compensation demand on the 10 kV side of the current substation is a basic compensation demand or a fluctuating compensation demand. This implementation method is based on the reactive power optimization decision of the entire network on a daily basis, optimizes based on the active and reactive power load data of 110 kV and 35 kV substations given by the daily power flow forecast, so as to give a reasonable switching plan for discrete reactive power devices; during the priority action period of discrete reactive power devices given by the daily reactive power optimization, the capacitors on the 10 kV busbar are preferentially adjusted; during other periods, the reactive power resources of the 10 kV feeder are preferentially adjusted.

[0109] The hierarchical voltage coordination control of the substation and the distribution network AVC mainly considers that when the reactive power regulation capacity in the 10kV feeder area of the distribution network is insufficient and the substation area voltage is too high or too low and exceeds the limit, the local dispatching AVC controls the taps or capacitors in the 110kV and 35kV substations to assist the distribution network in voltage regulation. The distribution network AVC detects the voltage operation conditions and reactive power resources in the distribution network in real time and uploads them to the local dispatching AVC; when the voltage regulation capacity in the distribution network area is insufficient, the coordination control limit values of the main and distribution network boundary buses are formed in real time, and the local dispatching AVC adjusts the reactive power resources in the area to support the distribution network voltage.

[0110] The interaction schematic diagram of the distribution network voltage control and the transmission network AVC is as Figure 4 shown. The system uploads the voltage regulation requirements to the local dispatching AVC according to the detected voltage distribution in the distribution network. The AVC accepts the voltage regulation requirements as constraints, so as to ensure that the AVC strategy on the transmission network side meets the voltage regulation requirements of the distribution network control.

[0111] Through the above implementation method, compared with the prior art, the present invention proposes a reactive power and voltage control scheme for a distribution network considering distributed photovoltaics. First, the reactive power control decision analysis of the 10kV distribution network is carried out, which mainly includes two stages. The first stage is the reactive power control decision analysis of the 10kV feeder, and the second stage is the reactive power control decision analysis of the substation area. Then, the hierarchical reactive power coordination control of the substation and the distribution network reactive power and voltage control system is carried out. Finally, the substation and the distribution network voltage system carry out collaborative control of the lower-level voltage.

[0112] The present invention solves the problem of hierarchical voltage coordination control of the 10kV and low-voltage 380V on the load side of the power grid in the field of reactive power and voltage optimization regulation, and improves the reliability and safety of the power grid operation.

[0113] The following is a detailed description in combination with another embodiment.

[0114] Embodiment 2

[0115] A reactive power and voltage control device for a distribution network provided in this embodiment includes a plurality of implementation units. Each implementation unit corresponds to each implementation step in the first embodiment above. The specific implementation method and beneficial effects can refer to the foregoing method embodiment and will not be elaborated here.

[0116] Figure 5 is a schematic diagram of an optional reactive power and voltage control device for a distribution network according to an embodiment of the present invention, as Figure 5 shown. The reactive power and voltage control device for the distribution network may include: a voltage measurement unit 51, a reactive power regulation amount calculation unit 52, a planning model construction unit 53, a reactive power demand analysis unit 54, and a resource coordination unit 55.

[0117] Among them, the voltage measurement unit 51 is used to measure the root node voltage of the 10 kV bus in the predetermined coordinated control area of the distribution network. Each 10 kV bus is correspondingly connected to at least one distribution feeder, and reactive power processing and regulation instructions have been preset on the distribution transformer areas of each distribution feeder.

[0118] The reactive power regulation amount calculation unit 52 is used to calculate the total reactive power regulation amount of each distribution feeder according to the voltage optimization target value of the 10 kV bus and the root node voltage.

[0119] The planning model construction unit 53 is used to determine each distribution transformer area in each distribution feeder as an equivalent regulated generator model in the predetermined coordinated control area, and construct a quadratic programming model based on the equivalent regulated generator model and the reactive power regulation capabilities of each distribution feeder.

[0120] The reactive power demand analysis unit 54 is used to perform reactive power demand analysis on the distribution transformer areas connected to each distribution feeder by using the quadratic programming model based on the total reactive power regulation amount of the feeder, and obtain the reactive power regulation data corresponding to each distribution feeder participating in the regulation. The reactive power regulation data includes: the reactive power adjustment amount, voltage adjustment amount, and voltage adjustment target value of each distribution transformer area.

[0121] The resource coordination unit 55 is used to coordinate and control the reactive power and voltage resources of the distribution network according to the reactive power regulation data. The reactive power and voltage resources include the reactive power of distributed photovoltaics and reactive power compensation devices.

[0122] The reactive power and voltage control device for the above distribution network can measure the root node voltage of the 10 kV bus in the predetermined coordinated control area of the distribution network through the voltage measurement unit 51. The total reactive power regulation amount of each distribution network feeder can be calculated by the reactive power regulation amount calculation unit 52 according to the voltage optimization target value of the 10 kV bus and the root node voltage. In the predetermined coordinated control area, the planning model construction unit 53 determines each distribution transformer substation area in each distribution network feeder as an equivalent regulated generator model, constructs a quadratic programming model based on the equivalent regulated generator model and the reactive power regulation capabilities of each distribution network feeder. The reactive power demand analysis unit 54 uses the quadratic programming model to perform reactive power demand analysis on the distribution transformer substation areas connected to each distribution network feeder based on the total reactive power regulation amount of the feeder, and obtains the reactive power regulation data corresponding to each distribution network feeder participating in the regulation. Among them, the reactive power regulation data includes: the reactive power adjustment amount, voltage adjustment amount and voltage adjustment target value of each distribution transformer substation area. The resource coordination unit 55 coordinates and controls the reactive power and voltage resources of the distribution network according to the reactive power regulation data. Among them, the reactive power and voltage resources include the reactive power of distributed photovoltaics and reactive power compensation devices. In this embodiment, the reactive power demand analysis can be performed on the distribution transformer substation areas connected to each distribution network feeder by using the quadratic programming model, and the reactive power regulation data corresponding to each distribution network feeder participating in the regulation can be obtained, and the reactive power and voltage resources of the distribution network can be coordinated and controlled, so as to fully mobilize the reactive power regulation potential in the distribution network, combined with the regulation of conventional reactive power compensation devices (such as capacitors and reactors), to achieve the optimal allocation of reactive power resources. It can not only reduce the frequent operation of reactive power equipment, reduce equipment losses, but also improve the overall operation efficiency of the system, thus solving the technical problems in the related art that the reactive power regulation resources cannot be fully utilized, easily cause frequent operation of equipment, and affect the service life of equipment.

[0123] Optionally, the reactive power regulation amount calculation unit includes: an index calculation module, which is used to calculate the reactive power adjustment balance index of each distribution network feeder based on the current reactive power value of the distribution network feeder, the upper limit value and the lower limit value of the reactive power adjustment of the distribution network feeder; a reactive power regulation amount calculation module, which is used to input the root node voltage of the 10 kV bus, the voltage optimization target value, the sensitivity of the reactive power injected into the 10 kV bus to the voltage, the reactive power adjustment balance index of the distribution network feeder, and the weight value of the corresponding reactive power balance target into the feeder reactive power regulation model, and calculate the total reactive power regulation amount of the distribution network feeder.

[0124] Optionally, the constraint conditions of the feeder reactive power regulation model include: the voltage of the 10 kV bus is within the limit range, and the reactive power regulation ability of the distribution network feeder is within the regulation ability range of the reactive power and voltage resources in the distribution transformer substation area.

[0125] Optionally, the reactive power demand analysis unit includes: a parameter measurement module for measuring the reactive power sensitivity of each distribution transformer substation area to the root node of the distribution network feeder, the current active power loss value in the distribution network feeder area, and the sensitivity of the reactive power adjustment of each distribution transformer substation area to the total active power loss in the distribution network feeder area; a reactive power regulation data calculation module for inputting the current reactive power of the root node of the distribution network feeder, the total reactive power regulation amount of the feeder, the reactive power sensitivity of the distribution transformer substation area to the root node of the distribution network feeder, the current active power loss value in the distribution network feeder area, and the sensitivity of the reactive power adjustment of each distribution transformer substation area to the total active power loss in the distribution network feeder area into a quadratic programming model, and calculating the reactive power regulation data corresponding to each distribution network feeder participating in the regulation.

[0126] Optionally, the constraint conditions of the quadratic programming model include: the voltage of the busbars of each distribution transformer substation area in the distribution network feeder area is within the limit range, and the reactive power regulation ability of the distribution transformer substation area is within the regulation ability range of the reactive power and voltage resources of the distributed new energy it serves.

[0127] Optionally, the resource coordination unit includes: a demand type detection module for detecting the demand type of the reactive power compensation of the superior substation corresponding to the distribution network; a device switching module for switching discrete reactive power devices during the period of load base change based on the demand type, where the discrete reactive power devices include in-station capacitors and reactors; a resource regulation module for regulating the reactive power and voltage resources of the distribution network itself during the period of load fluctuation.

[0128] Optionally, the resource coordination unit includes: a coordination limit calculation module for calculating the voltage coordination limit of the 10kV busbar when it is detected that the reactive power and voltage resources of the distribution network itself are exhausted; a limit sending module for sending the voltage coordination limit of the 10kV busbar to the automatic voltage control system AVC of the superior substation corresponding to the distribution network, where AVC completes the voltage regulation of the distribution network area by adjusting the reactive power devices in the superior substation.

[0129] The reactive power and voltage control device of the above distribution network may further include a processor and a memory. The above voltage measurement unit 51, reactive power regulation amount calculation unit 52, planning model construction unit 53, reactive power demand analysis unit 54, resource coordination unit 55, etc. are all stored in the memory as program units, and the processor executes the above program units stored in the memory to implement corresponding functions.

[0130] The above 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 and voltage optimization and coordinated control are realized by adjusting the kernel parameters.

[0131] The above-mentioned memory may include non-permanent memory in the form of computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0132] Embodiment III

[0133] An embodiment of the present application may provide an electronic device. Figure 6 is a structural block diagram of an electronic device according to an embodiment of the present application. As Figure 6 shown, the electronic device may include: one or more ( Figure 6 only one is shown in the figure) processors 602, a memory 604, a storage controller, and a peripheral interface, wherein the peripheral interface is connected to a radio frequency module, an audio module, and a display.

[0134] Among them, the memory can be used to store software programs and modules, such as program instructions / modules corresponding to the reactive voltage control method and device of the distribution network in the embodiments 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 control method of the distribution network. The memory may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memories. In some instances, the memory may further include a memory remotely provided relative to the processor, and these remote memories can be connected to the terminal through a network. Examples of the above-mentioned network include but are not limited to the Internet, enterprise intranet, local area network, mobile communication network, and combinations thereof.

[0135] The processor can call the information and application programs stored in the memory through the transmission device to perform the following steps: measure the root node voltage of the 10kV bus in the predetermined coordinated control area of the distribution network, where each 10kV bus is correspondingly connected to at least one distribution network feeder, and reactive power treatment and regulation instructions have been preset on the distribution transformer substations of each distribution network feeder; calculate the total reactive power regulation amount of each distribution network feeder according to the voltage optimization target value of the 10kV bus and the root node voltage; in the predetermined coordinated control area, determine each distribution transformer substation in each distribution network feeder as an equivalent regulation generator model, and construct a quadratic programming model based on the equivalent regulation generator model and the reactive power regulation capabilities of each distribution network feeder; based on the total reactive power regulation amount of the feeder, use the quadratic programming model to analyze the reactive power demand of the distribution transformer substations connected to each distribution network feeder, and obtain the reactive power regulation data corresponding to each distribution network feeder participating in the regulation, where the reactive power regulation data includes: the reactive power adjustment amount, voltage adjustment amount, and voltage adjustment target value of each distribution transformer substation; coordinate and control the reactive power and voltage resources of the distribution network according to the reactive power regulation data, where the reactive power and voltage resources include the reactive power of distributed photovoltaics and reactive power compensation devices.

[0136] Those of ordinary skill in the art can understand that Figure 6 the structure shown is only schematic, and the electronic device can also be a terminal device such as a smart phone, a tablet computer, a handheld computer, and a Mobile Internet Device (MID), a PAD, etc. Figure 6 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 those shown in Figure 6 or have a different configuration from that shown in Figure 6 shown.

[0137] Those of ordinary skill in the art can understand that all or part of the steps in the various reactive power and voltage control 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, and the storage medium can include: a flash drive, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disc, etc.

[0138] Embodiment 4

[0139] The embodiment of the present application also provides a storage medium. Optionally, in this embodiment, the above storage medium can be used to store the program code executed by the reactive power and voltage control method of the distribution network provided in Embodiment 1 above.

[0140] 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 power voltage control method of the distribution network in any one of the above-mentioned Embodiment 1.

[0141] Optionally, in this embodiment, the above storage medium may be located in any one of the computer terminals in the computer terminal group in the computer network, or in any one of the mobile terminals in the mobile terminal group.

[0142] 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 power voltage control method of the distribution network in each embodiment of the present application.

[0143] 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 power voltage control method of the distribution network in each embodiment of the present application.

[0144] 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.

[0145] In the above embodiments of the present invention, the descriptions of each embodiment have their own emphases. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0146] 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 couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the units or modules can be in electrical or other forms.

[0147] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place, or they can be distributed to multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0148] In addition, in each embodiment of the present invention, the functional units can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0149] If the above-mentioned 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 such an 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 aforementioned storage medium includes: various media such as USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks, or optical discs that can store program codes.

[0150] The above 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 reactive voltage control method for a distribution network, characterized in that: include: Measuring the root node voltage of a 10 kV bus in a predetermined coordinated control area of ​​the distribution network, wherein each 10 kV bus is connected to at least one distribution network feeder, and a reactive power processing adjustment instruction has been pre-set on the distribution transformer area of ​​each distribution network feeder; Calculate the total reactive power regulation of each distribution network feeder according to the voltage optimization target value of the 10kV bus and the root node voltage; In the predetermined coordinated control area, each distribution transformer area in each distribution network feeder is determined as an equivalent regulation generator model, and a quadratic programming model is constructed based on the equivalent regulation generator model and the reactive power regulation capability of each distribution network feeder; Based on the total reactive power regulation of the feeder, the quadratic programming model is used to perform reactive power demand analysis on the distribution transformer area connected to each distribution network feeder, and reactive power regulation data corresponding to each distribution network feeder involved in the regulation is obtained, wherein the reactive power regulation data includes: reactive power adjustment amount, voltage adjustment amount and voltage adjustment target value of each distribution transformer area; According to the reactive regulation data, the reactive voltage resources of the distribution network are coordinated and controlled, wherein the reactive voltage resources include the reactive power of distributed photovoltaics and reactive compensation equipment.

2. The reactive voltage control method according to claim 1, characterized in that: The step of calculating the total reactive power regulation amount of each distribution network feeder according to the voltage optimization target value of the 10kV bus and the root node voltage comprises: For each of the distribution network feeders, based on the current reactive power value of the distribution network feeder, the reactive power adjustment upper limit value and the reactive power adjustment lower limit value of the distribution network feeder, calculate the reactive power adjustment balance index of the distribution network feeder; The root node voltage of the 10kV bus, the voltage optimization target value, the sensitivity of the 10kV bus injected reactive power to voltage, the reactive adjustment balance index of the distribution network feeder and the corresponding weight value of the reactive balance target are input into the feeder reactive regulation model to calculate the total reactive regulation amount of the distribution network feeder.

3. The reactive voltage control method according to claim 2, characterized in that: The constraint conditions of the feeder reactive power regulation model include: the voltage of the 10kV bus is within the limit range, and the reactive power regulation capability of the distribution network feeder is within the regulation capability range of the reactive power voltage resources in the distribution transformer area.

4. The reactive voltage control method according to claim 1, characterized in that: Based on the total reactive power regulation of the feeder, the steps of using the quadratic programming model to perform reactive power demand analysis on the distribution transformer area of ​​each distribution network feeder to obtain reactive power regulation data corresponding to each distribution network feeder involved in the regulation include: Measuring the reactive sensitivity of each distribution transformer area to the root node of the distribution network feeder, the current active network loss value of the distribution network feeder area, and the sensitivity of the reactive adjustment of each distribution transformer area to the total active network loss in the distribution network feeder area; The current reactive power of the distribution network feeder root node, the total reactive power regulation of the feeder, the reactive sensitivity of the distribution transformer area to the distribution network feeder root node, the current active network loss value of the distribution network feeder area, and the sensitivity of the reactive power adjustment of each distribution transformer area to the total active network loss in the distribution network feeder area are input into the quadratic programming model to calculate the reactive power regulation data corresponding to each distribution network feeder involved in the regulation.

5. The reactive voltage control method according to claim 4, characterized in that: The constraints of the secondary programming model include: the voltage of the busbars of each distribution transformer area in the distribution network feeder area is within the limit range, and the reactive power regulation capacity of the distribution transformer area is within the regulation capacity range of the reactive power voltage resources of the distributed new energy.

6. The reactive voltage control method according to claim 1, characterized in that: The step of coordinating and controlling the reactive voltage resources of the distribution network according to the reactive regulation data comprises: Detecting the type of reactive power compensation demand of the upper-level substation corresponding to the distribution network; Based on the demand type, during the period of load base change, discrete reactive equipment is switched on and off, wherein the discrete reactive equipment includes capacitors and reactors within the station; during the period of load fluctuation, the reactive voltage resources of the distribution network itself are adjusted.

7. The reactive voltage control method according to claim 6, characterized in that: The step of coordinating and controlling the reactive voltage resources of the distribution network according to the reactive regulation data comprises: When it is detected that the reactive voltage resources of the distribution network itself are exhausted, calculating the voltage coordination limit value of the 10kV bus; The voltage coordination limit of the 10kV bus is sent to the automatic voltage control system AVC of the upper-level substation corresponding to the distribution network, wherein the AVC completes the voltage regulation in the distribution network area by adjusting the reactive equipment in the upper-level substation.

8. A reactive voltage control device for a distribution network, characterized in that: include: A voltage measurement unit is used to measure the root node voltage of a 10kV bus in a predetermined coordinated control area of ​​the distribution network, wherein each 10kV bus is connected to at least one distribution network feeder, and a reactive power processing adjustment instruction has been pre-set on the distribution transformer area of ​​each distribution network feeder; A reactive regulation amount calculation unit, used to calculate the total reactive regulation amount of each distribution network feeder according to the voltage optimization target value of the 10kV bus and the root node voltage; A planning model construction unit, configured to determine, in the predetermined coordinated control area, each distribution transformer area in each distribution network feeder as an equivalent regulation generator model, and construct a secondary planning model based on the equivalent regulation generator model and the reactive power regulation capability of each distribution network feeder; A reactive demand analysis unit is used to perform reactive demand analysis on the distribution transformer area connected to each distribution network feeder based on the total reactive adjustment amount of the feeder, using the quadratic programming model, to obtain reactive adjustment data corresponding to each distribution network feeder involved in the adjustment, wherein the reactive adjustment data includes: reactive adjustment amount, voltage adjustment amount and voltage adjustment target value of each distribution transformer area; A resource coordination unit is used to coordinate and control the reactive voltage resources of the distribution network according to the reactive regulation data, wherein the reactive voltage resources include the reactive power of distributed photovoltaics and reactive compensation equipment.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located is controlled to execute the reactive voltage control method for the distribution network according to any one of claims 1 to 7.

10. 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 control method for the distribution network as described in any one of claims 1 to 7.

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