Inertia coordination control method and device for multiple virtual synchronous machine systems in power distribution network area

Abstract

The invention relates to a power distribution network zone area multi-virtual synchronous machine system inertia coordination control method and device, and the method comprises the steps: obtaining the equipment dynamic characteristics and line impedance of a system in a power distribution network zone area multi-virtual synchronous machine system; according to the dynamic characteristics of the equipment and the optimal configuration of the equipment inertia parameters of all the equipment in the line impedance generation system, the size and distribution of the inertia of all the equipment are dynamically adjusted; and based on the optimal configuration of the equipment inertia parameter of each piece of equipment, collaborative optimization is carried out in combination with the parameters of the adjustable unit in the transformer area. According to the embodiment of the invention, a power distribution network area multi-machine inertia coordination control strategy is provided based on the network node inertia equivalent model in combination with the adjustable characteristic of the virtual inertia, the dispersion of frequency response among equipment in the area is remarkably inhibited while the inertia support requirement of a grid-connected point is ensured, and the reliability of the system is improved. And the method has an important guiding value for optimal configuration of inertia resources of the power system.

Description

Technical Field

[0001] The present application relates to the technical field of multi-machine inertia coordinated control within a substation area, and particularly relates to a method and device for inertia coordinated control of a multi-virtual synchronous machine system in a distribution network substation area. Background Technique

[0002] With the continuous weakening of the inertia level of the distribution network substation area with high proportion of new energy penetration, the virtual inertia control technology based on distributed power sources and energy storage systems has become an important means to maintain the frequency stability of the grid connection point. However, existing research mainly focuses on the design of single-machine virtual inertia control strategies, ignoring the coordination problem of inertia support capabilities in the multi-machine system scenario. Since the advantage of virtual inertia technology lies in the fact that its parameters can be adjusted in real time, it is possible to coordinate and optimize the magnitudes and distributions of the inertias of various devices within the substation area, so as to achieve flexible control of the inertia support of the multi-machine system for the grid connection point.

[0003] Since the rotational inertia of a synchronous machine is provided by physical structures such as the rotor and its inertia magnitude cannot be changed, while the advantage of the virtual inertia of a VSG (Virtual Synchronous Generator) is that the magnitude of the virtual inertia can be changed in real time by changing parameters, enabling the system to operate more quickly and stably. Therefore, taking advantage of this characteristic of the VSG, a VSG control strategy with alternating virtual inertia is proposed. The value of the virtual inertia parameter is changed according to the difference between the virtual angular velocity and the grid connection point angular frequency and its rate of change, so that the inertia of the device is in a high and low alternating state after a disturbance occurs. The damping effect of this strategy is studied through transient energy analysis, and the stability of the alternating inertia control strategy is illustrated by the energy function method.

[0004] Currently, most of the research on inertia control focuses on single-machine systems, and there is relatively little research on inertia control strategies for multi-machine systems and multi-substation networks. A stable control and inertia coordination method for multi-VSG parallel operation uses the traditional inertia coordination method where inertia is proportional to capacity to ensure that each VSG can still distribute the load according to the capacity ratio under disturbances. Each unit adopts a coordination strategy where inertia is proportional to capacity, which can reduce the power oscillation in the transient process to a certain extent. Based on an optimization method, the virtual inertia parameters and damping coefficients are jointly tuned, using the minimum kinetic energy deviation or the maximum oscillation mode damping ratio as the optimization goal, achieving the dynamic frequency stability control of the microgrid system. However, it is necessary to obtain the complete frequency curve of each unit for calculation, and multiple iterations are required with a large amount of computation. A control strategy for multi-VSG parallel operation in a distributed network adds a mutual damping term related to the frequency of adjacent VSGs to the rotor motion equation link of each VSG, making the output frequencies of each VSG tend to the same value and improving the power oscillation in the traditional multi-VSG control mode. Similarly, for a multi-VSG microgrid, based on the consensus principle of multi-agent, by adding a term related to the frequency difference of adjacent VSGs to the inertia parameter, it also achieves the effect of suppressing the excessive frequency difference between adjacent VSGs in the rotor motion equation. However, these studies have strong dependence on and communication coupling with adjacent node information, resulting in certain limitations in terms of reliability, dynamic adaptability, and large-scale expansion. Summary of the Invention

[0005] This application provides an inertia coordination control method and device for a multi-virtual synchronous generator system in a distribution network substation area to solve the problems that existing research mainly focuses on the design of single-machine virtual inertia control strategies, ignoring the coordination problem of inertia support capabilities in the multi-machine system scenario. Currently, most of the research on inertia control focuses on single-machine systems, and there is relatively little research on inertia control strategies for multi-machine systems and multi-substation networks. Moreover, the related technologies have strong dependence on and communication coupling with adjacent node information, resulting in certain limitations in terms of reliability, dynamic adaptability, and large-scale expansion.

[0006] The first aspect of the embodiments of this application provides an inertia coordination control method for a multi-virtual synchronous generator system in a distribution network substation area, including the following steps: In the multi-virtual synchronous generator system of the distribution network substation area, obtain the equipment dynamic characteristics and line impedance of the system; generate the optimal configuration of the equipment inertia parameters of each device in the system according to the equipment dynamic characteristics and line impedance to dynamically adjust the magnitude and distribution of the inertia of each device; based on the optimal configuration of the equipment inertia parameters of each device, perform collaborative optimization in combination with the parameters of the adjustable units within the substation area.

[0007] Optionally, in an embodiment of the present application, generating an optimal configuration of the inertia parameters of each device in the system according to the dynamic characteristics of the device and the line impedance includes: obtaining the inertia parameters of each generator and virtual synchronous machine device and the line impedance based on the network node inertia equivalent model; calculating the inertia at the grid connection point of the target distribution area according to the inertia parameters of each generator and virtual synchronous machine device and the line impedance.

[0008] Optionally, in an embodiment of the present application, it further includes: obtaining the initial instantaneous frequency change rate of each unit after the disturbance; obtaining the adjustment values of the inertia and damping parameters of the virtual inertia control by using the initial instantaneous frequency change rate of each unit after the disturbance based on a preset control strategy.

[0009] Optionally, in an embodiment of the present application, the dynamic response formula of the unit frequency of each unit is:

[0010]

[0011] where f is the unit frequency, H is the virtual inertia constant of the unit, and D is the damping coefficient.

[0012] Optionally, in an embodiment of the present application, the first device inertia configuration formula of each device is:

[0013]

[0014] where i is the unit, H PCC is the inertia at the grid connection point, T G-PCC,i is the power distribution coefficient between the generator i and the grid connection point, S sys is the system capacity, S G is the generator capacity.

[0015] Optionally, in an embodiment of the present application, the second device inertia configuration formula of each device is:

[0016]

[0017] where T PCC-grid is the power distribution coefficient of the upper-level main grid at the grid connection point, T grid-PCC =T PCC-grid is the power distribution coefficient between the generator i and the grid connection point, H PCC is the inertia at the grid connection point, S sys is the system capacity, H grid is the equivalent inertia, S grid is the equivalent inertia of the distribution network generator, S G is the generator capacity.

[0018] The second aspect of the present application provides an inertia coordination control device for a multi-virtual synchronous machine system in a distribution network substation area, including: an acquisition module, configured to acquire the device dynamic characteristics and line impedance of the system in the multi-virtual synchronous machine system of the distribution network substation area; a generation module, configured to generate an optimal configuration of the device inertia parameters of each device in the system according to the device dynamic characteristics and line impedance, so as to dynamically adjust the magnitude and distribution of the inertia of each device; a collaborative optimization module, configured to perform collaborative optimization based on the optimal configuration of the device inertia parameters of each device and in combination with the parameters of the adjustable units inside the substation area.

[0019] Optionally, in an embodiment of the present application, the generation module includes: an acquisition unit, configured to acquire the inertia parameters of each generator and virtual synchronous machine device and the line impedance based on the network node inertia equivalent model; a calculation unit, configured to calculate the inertia at the grid connection point of the target substation area according to the inertia parameters of each generator and virtual synchronous machine device and the line impedance.

[0020] Optionally, in an embodiment of the present application, it further includes: a change rate acquisition module, configured to acquire the initial instantaneous frequency change rate of each unit after a disturbance; an adjustment value acquisition module, configured to obtain the adjustment values of the inertia and damping parameters of the virtual inertia control based on a preset control strategy and using the initial instantaneous frequency change rate of each unit after the disturbance.

[0021] Optionally, in an embodiment of the present application, the dynamic response formula of the unit frequency of each device is:

[0022]

[0023] where f is the unit frequency, H is the virtual inertia constant of the unit, and D is the damping coefficient.

[0024] Optionally, in an embodiment of the present application, the first device inertia configuration formula of each device is:

[0025]

[0026] where i is the unit, H PCC is the inertia at the grid connection point, T G-PCC,i is the power distribution coefficient between the generator i and the grid connection point, S sys is the system capacity, S G is the generator capacity.

[0027] Optionally, in an embodiment of the present application, the second device inertia configuration formula of each device is:

[0028]

[0029] where T PCC-gridis the power distribution coefficient of the upper main grid at the grid connection point, T grid-PCC =T PCC-grid is the power distribution coefficient between the generator i and the grid connection point, H PCC is the grid-connected point inertia, S sys is the system capacity, H grid is the equivalent inertia, S grid is the equivalent distribution network generator inertia, S G is the generator capacity.

[0030] The third aspect of the present application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the inertia coordination control method for a multi-virtual synchronous machine system in a distribution network substation as described in the above embodiment.

[0031] The fourth aspect of the present application provides a computer-readable storage medium, which stores a computer program. When the program is executed by a processor, it implements the above-mentioned method for coordinated inertia control of multiple virtual synchronous machine systems in a distribution network substation.

[0032] A fifth aspect of the present application provides a computer program product, which stores a computer program that, when executed by a processor, implements the above-mentioned method for coordinated inertia control of multiple virtual synchronous machine systems in a distribution network substation.

[0033] The embodiment of the present application is based on the network node inertia equivalent model, combined with the adjustable characteristics of virtual inertia, and proposes a coordinated control strategy for the inertia of multiple machines in the distribution network substation. While ensuring the inertia support requirements of the grid connection point, it significantly suppresses the dispersion of frequency response between devices within the substation, and has important guiding value for the optimal configuration of inertia resources in the power system. As a result, it solves the problem that existing research focuses on the design of single-machine virtual inertia control strategies, ignoring the coordination problem of inertia support capabilities in multi-machine system scenarios, and most of the current research on inertia control is for single-machine systems, and there are fewer studies on inertia control strategies for multi-machine systems and multi-station networks. In addition, the relevant technology has a strong dependence on adjacent node information and communication coupling, resulting in certain limitations in reliability, dynamic adaptability and large-scale expansion.

[0034] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0036] Figure 1 It is a flowchart of an inertia coordinated control method for a multi-virtual synchronous machine system in a distribution network substation area provided according to an embodiment of the present application;

[0037] Figure 2 It is a schematic structural diagram of an inertia coordinated control device for a multi-virtual synchronous machine system in a distribution network substation area provided according to an embodiment of the present application;

[0038] Figure 3 It is a schematic structural diagram of an electronic device provided according to an embodiment of the present application. Specific embodiments

[0039] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, and should not be construed as a limitation to the present application.

[0040] The inertia coordinated control method and device for a multi-virtual synchronous machine system in a distribution network substation area according to an embodiment of the present application will be described below with reference to the drawings. In view of the problem that most of the existing studies in the above-mentioned background technology focus on the design of single-machine virtual inertia control strategies, ignoring the coordination problem of inertia support capabilities in the multi-machine system scenario, and most of the current studies on inertia control are for single-machine systems, there are few studies on inertia control strategies for multi-machine systems and multi-substation networks, and the related technologies have strong dependence on adjacent node information and communication coupling, resulting in certain limitations in terms of reliability, dynamic adaptability, and large-scale expansion, the present application provides an inertia coordinated control method for a multi-virtual synchronous machine system in a distribution network substation area. In this method, based on the network node inertia equivalent model and combined with the adjustable characteristics of virtual inertia, an inertia coordinated control strategy for multi-machines in a distribution network substation area is proposed. While ensuring the inertia support requirements at the grid connection point, it significantly suppresses the dispersion of frequency responses among internal devices in the substation area, and has important guiding value for the optimal allocation of inertia resources in the power system. Thus, the problem that most of the existing studies focus on the design of single-machine virtual inertia control strategies, ignoring the coordination problem of inertia support capabilities in the multi-machine system scenario, and most of the current studies on inertia control are for single-machine systems, there are few studies on inertia control strategies for multi-machine systems and multi-substation networks, and the related technologies have strong dependence on adjacent node information and communication coupling, resulting in certain limitations in terms of reliability, dynamic adaptability, and large-scale expansion is solved.

[0041] Specifically, Figure 1 It is a schematic flowchart of an inertia coordinated control method for a multi-virtual synchronous machine system in a distribution network substation area provided by an embodiment of the present application.

[0042] As Figure 1As shown, the inertia coordinated control method for the multi-virtual synchronous machine system in the distribution network substation area includes the following steps:

[0043] In step S101, in the multi-virtual synchronous machine system of the distribution network substation area, obtain the device dynamic characteristics and line impedance of the system.

[0044] In the actual implementation process, the key advantage of the virtual inertia technology in the embodiments of this application is that its parameters can be adjusted in real time. In a multi-machine system, the size and distribution of the inertia of each device can be dynamically adjusted to achieve flexible control of the inertia support at the grid connection point of the multi-machine system. At this time, a coordinated control strategy is needed to guide the design of the inertia parameters. Simply relying on the local control of the inertia parameter setting is difficult to ensure the optimal overall support efficiency of the system. Therefore, it is necessary to construct a virtual inertia optimization distribution mechanism for multi-machine cooperation. By establishing a coordinated control strategy considering the device dynamic characteristics and line impedance in the multi-virtual synchronous machine system of the distribution network substation area, it provides support for the subsequent realization of the optimal configuration of the inertia parameters of each device.

[0045] In step S102, generate the optimal configuration of the device inertia parameters of each device in the system according to the device dynamic characteristics and line impedance, so as to dynamically adjust the size and distribution of the inertia of each device.

[0046] Specifically, the embodiments of this application can establish a coordinated control strategy considering the device dynamic characteristics and line impedance, generate the optimal configuration of the device inertia parameters of each device in the system according to the device dynamic characteristics and line impedance, so as to dynamically adjust the size and distribution of the inertia of each device, thereby coordinating and optimizing the size and distribution of the inertia of each device in the substation area, and providing support for realizing flexible control of the inertia support at the grid connection point of the multi-machine system.

[0047] The embodiments of this application consider factors such as the inertia support of each virtual synchronous machine device and line impedance, and propose a multi-machine virtual inertia coordinated control strategy to achieve the optimal distribution of multi-machine inertia in the substation area.

[0048] Optionally, in an embodiment of this application, generating the optimal configuration of the device inertia parameters of each device in the system according to the device dynamic characteristics and line impedance includes: based on the network node inertia equivalent model, obtain the inertia parameters of each generator and virtual synchronous machine device and the line impedance; calculate the inertia at the grid connection point of the target substation area according to the inertia parameters of each generator and virtual synchronous machine device and the line impedance.

[0049] In the actual implementation process, the embodiments of this application can obtain the inertia parameters of each generator and virtual synchronous machine device and the line impedance based on the network node inertia equivalent model, and calculate the inertia at the grid connection point of the target substation area according to the inertia parameters of each generator and virtual synchronous machine device and the line impedance.

[0050] When the synchronous machine is subjected to a power disturbance, its rotor motion equation at the initial moment of the disturbance can be expressed as:

[0051]

[0052] By using the node inertia equivalent method shown in Equation (2), after obtaining the inertia parameters of each generator and virtual synchronous machine equipment and the line impedance, the inertia of the grid connection point in the distribution area can be calculated to quantitatively evaluate the support ability of the distribution area to the upper-level power grid.

[0053]

[0054] When the upper-level power grid issues an inertia support demand instruction to the distribution area, based on the equivalent inertia model of the grid connection point established by Equation (2), theoretically, the target inertia level can be achieved by adjusting the virtual inertia parameters of each unit. However, under the constraints of the physical network structure, the distribution characteristics of the line impedance and the unit connection position jointly determine the initial power disturbance amount of each unit At this time, it can be seen from the rotor motion equation of Equation (1) that if the parameter setting is simply optimized with the inertia of the grid connection point meeting the standard, and the inertia parameters of each machine are set unreasonably, the rate of change of frequency (RoCoF) responses of each unit in the initial stage of the power grid disturbance show significant differences. Specifically, the units with high inertia parameters show over-damping characteristics, while the units with low inertia parameters show frequency dynamic overshoot phenomena. This phenomenon of excessive RoCoF differences may cause the local frequency not to meet the requirements and even lead to power oscillations between units. Therefore, this application aims to make the initial instantaneous RoCoF of each unit equal after the disturbance, and through coordinating the inertia coefficients of each unit, while ensuring the inertia support ability of the grid connection point, the coordinated control of the inertia of multiple machines in the distribution area is achieved.

[0055] When a disturbance occurs at system node h, its rate of change of frequency can be expressed as:

[0056]

[0057] Among them, T hG is the frequency distribution matrix, and the values of its elements represent the contribution values of the frequencies of each generator to the frequency of the disturbance point, and the sum of the values of each element is 1.

[0058] The goal of designing the coordinated control strategy is that the rate of change of frequency of each unit at the initial moment is equal, that is:

[0059]

[0060] That is, if the rate of change of frequency of each unit at the initial moment is to be equal, then they are all equal to the rate of change of frequency of the disturbance point h. Substituting into the rotor motion equation, we can get:

[0061]

[0062] After arrangement, we get:

[0063] H G,i = T Gh,i ·H h , (7)

[0064] Similarly, when the unit capacities are different, the capacities of each unit can be used as the base value of their respective inertia coefficients. At this time, the inertia coordination strategy can be written as:

[0065]

[0066] The embodiment of this application can combine the adjustable characteristics of virtual inertia to propose a multi-machine inertia coordination control strategy for the distribution network substation area. While ensuring the inertia support requirements at the grid connection point, it significantly suppresses the dispersion of frequency responses among internal devices in the substation area, and has important guiding value for the optimal allocation of inertia resources in the power system.

[0067] Optionally, in an embodiment of this application, the first device inertia configuration formula for each device is:

[0068]

[0069] where i is the unit, H PCC is the inertia at the grid connection point, T G-PCC,i is the power distribution coefficient between generator i and the grid connection point, S sys is the system capacity, S G is the generator capacity.

[0070] It can be understood that the first device inertia configuration in the embodiment of this application can be: in a multi-machine system network, if it is required to make the inertia value at the grid connection point reach the inertia command value H ref , it is only necessary to configure the inertia of each power generation device according to formula (9).

[0071] where let H PCC > H ref , then it is possible to ensure that the initial values of RoCoF of each machine are the same at the moment of disturbance while meeting the inertia command requirements at the grid connection point.

[0072]

[0073] At the initial moment of disturbance, due to the different positions of generators and line impedances, there will be differences in the initial power distribution of each machine. The coordination control strategy with the same initial value of RoCoF does not change the distribution of disturbance power, but avoids the initial frequency change rate of some units from being too large and exceeding the limit that the unit can bear through the coordination of inertia parameters, resulting in problems such as mechanical equipment damage, misoperation of protection devices, and disconnection of new energy from the grid.

[0074] According to the Taylor expansion of the frequency in Equation (10), at the initial moment of the perturbation, the initial frequencies of all generators are equal. When the initial values of the frequency change rates are also equal, by truncating the second-order and higher-order components of the Taylor expansion, it can be deduced that within a short time window \(t\in(0,T)\) after the perturbation, the frequency deviations of each node have an approximately consistent evolution trend, and the units show cooperative response characteristics during the transient process, thus effectively weakening the power oscillation phenomenon caused by the difference in frequency change rates and effectively suppressing the dispersion of the frequency within the power distribution area.

[0075]

[0076] After the initial moment of the perturbation, there will be power circulation oscillation during the process of each unit reaching a new steady state. Next, the oscillation will be weakened by adjusting the inertia and damping parameters of the virtual inertia control. On the premise of ensuring the inertia support ability of the grid connection point, the coordinated optimization of frequency stability is realized.

[0077] The rotor motion equation of the synchronous machine is shown in Equation (1). Ignoring the dynamic process of the governor of the synchronous machine and assuming that a power perturbation of magnitude \(\Delta P\) is applied to the machine terminal at time \(t = 0\), the dynamic response of the unit frequency is shown in Equation (11).

[0078]

[0079] The relationship between the frequency change rate and the perturbation power at the initial moment of the perturbation is as follows:

[0080]

[0081] Optionally, in an embodiment of the present application, after arrangement, the dynamic response formula of the unit frequency of each unit is:

[0082]

[0083] where \(f\) is the unit frequency, \(H\) is the virtual inertia constant of the unit, and \(D\) is the damping coefficient.

[0084] At this time, making \(2H\) of each unit \(i\) G,i / D i all equal. If the initial values of their frequency change rates are also equal, the subsequent frequency curves can be guaranteed to be the same. Therefore, in the coordinated control of the transient response of the multi-machine system, first adjust the inertia parameter to make the initial values of the frequency change rates of each unit the same, and by adjusting the unit parameters, ensure that the virtual inertia coefficient of each unit is proportional to the equivalent damping coefficient, that is, each unit satisfies the two conditions shown in Equation (14). As a coordinated control strategy, the system will present a globally consistent frequency dynamic trajectory at this time.

[0085]

[0086] Among them, K is a constant and can be designed based on the system parameter situation.

[0087] At this time, the power exchange between the units in the system is as follows:

[0088]

[0089] Among them, K ij is the synchronous power transfer coefficient, which describes the magnitude of the power exchange between units i and j due to frequency deviation and can be calculated from the system network parameters.

[0090] Substituting Equation (13) gives the parameter calculation formula for the preset control strategy as:

[0091]

[0092] Among them, K ij is the synchronous power transfer coefficient, and both i and j are units.

[0093] It can be obtained that under the control strategy shown in Equation (14), the power exchange between the units is 0, and the power oscillation between the units can be effectively suppressed.

[0094] In step S103, based on the optimal configuration of the equipment inertia parameters of each device, the parameters of the adjustable units inside the substation area are combined for collaborative optimization.

[0095] It can be understood that from the above analysis, through the collaborative optimization configuration of the virtual inertia parameters and equivalent damping coefficients of each unit, the equivalent inertia of the grid connection point can be achieved and accurately controlled, and at the same time, the purpose of suppressing the dispersion of the internal frequency of the substation area and power oscillation can be achieved. However, due to hardware constraints and other reasons, not all units have the ability to adjust the virtual inertia. For example, when calculating the dynamic response of the grid connection point frequency, the inertia support ability of the upper-layer power grid needs to be considered. At this time, the upper-layer power grid can be equivalently regarded as a synchronous machine with a larger capacity, and its equivalent inertia is regarded as a constant.

[0096] In the actual execution process, in the embodiment of the present application, when designing the inertia coordination control strategy of the substation area, the inertia of the upper-layer power grid can be used as an uncontrollable parameter, and through the collaborative optimization of the parameters of the adjustable units inside the substation area, the system can meet the grid connection inertia requirement of H PCC >H ref , and based on the optimal configuration of the equipment inertia parameters of each device, the parameters of the adjustable units inside the substation area are combined for collaborative optimization.

[0097] When considering the inertia of the upper-layer power grid, the equivalent inertia of the node is:

[0098]

[0099] Under the operating conditions of a strong power grid, the equivalent impedance of the power grid is small, resulting in a term T in the power distribution matrix that represents the power distribution ratio of the power grid grid-h Under the operating conditions of a strong power grid, the equivalent impedance of the power grid is small, resulting in a term T in the power distribution matrix that represents the power distribution ratio of the power grid grid-h getting closer to 1. Thus, under the operating conditions of a strong power grid, the equivalent impedance of the power grid is small, resulting in a term T in the power distribution matrix that represents the power distribution ratio of the power grid grid getting closer to 1. Thus, under the same base value, the calculated value of the node inertia formula is basically the same as the power grid inertia H

[0100] Under the same base value, the calculated value of the node inertia formula is basically the same as the power grid inertia H grid The system inertia shows the characteristics of being dominated by the strong power grid, making the contribution of the local unit's virtual inertia deeply submerged. Generally, under weak grid conditions, the inertia support ability of the main grid for the connection point is weakened, and the change of the distributed unit's inertia has a greater adjustment effect on the inertia of the connection point. Therefore, a multi-machine inertia coordinated control strategy needs to be proposed to provide support for the inertia of the connection point

[0101] When considering the inertia of the upper-layer power grid, the formula for the rate of change of the disturbance point frequency can be written as a combination of the rate of change of the main grid frequency and the rate of change of each unit's frequency

[0102]

[0103] The rate of change of each unit's frequency is the same, that is

[0104]

[0105] Substituting into their respective rotor motion equations gives

[0106]

[0107] After sorting out, we get

[0108]

[0109] Optionally, in an embodiment of the present application, the second device inertia configuration formula of each device is

[0110]

[0111] where T PCC-grid is the power distribution coefficient of the upper-layer main grid at the connection point, T grid-PCC = T PCC-grid is the power distribution coefficient between generator i and the connection point, H PCCThe inertia at the point of common coupling is \(S\). sys The system capacity is \(H\). grid The equivalent inertia is \(S\). grid The equivalent inertia of the distribution network generator is \(S\). G The generator capacity is...

[0112] It can be understood that the second device inertia configuration of each device in the embodiments of the present application can be as follows: when the unit capacities are different, the capacities of each unit can be used as the base values of their respective inertia coefficients. That is, in a multi-machine system network, to make the inertia value at the point of common coupling reach the inertia command value \(H\). ref If the inertia support characteristics of the main network are known, only the inertia of each power generation device needs to be configured according to Equation (22).

[0113] Among them, let the inertia at the point of common coupling be \(H\). PCC \(>H\). ref That is, while meeting the requirements of the inertia command at the point of common coupling, it can ensure that the initial values of RoCoF of each machine are the same at the moment of disturbance. At the same time, according to Equation (14), it is satisfied that the virtual inertia coefficient of each unit is proportional to the equivalent damping coefficient to suppress the power oscillation between units.

[0114]

[0115] Among them, \(T\). PCC-grid Is the power distribution coefficient of the upper-layer main network at the point of common coupling and is a constant.

[0116] This strategy can reduce the frequency dispersion within the units in the substation area, but it cannot suppress the power oscillation between them and the synchronous machines in the upper-layer distribution network, resulting in a still long frequency oscillation recovery time for each machine. Since the inertia parameters and capacities of the synchronous machines are fixed values, at the initial moment of disturbance, the power disturbance distribution of each unit is only related to the line impedance. If the equivalent inertia at the point of common coupling is to be equal to the inertia command value, that is, \(H\). PCC \(=H\). ref Then the requirement that the power disturbance distribution is proportional to the inertia cannot be met, and there will be a significant difference in the initial values of RoCoF between the units in the substation area and the synchronous machines in the upper-layer distribution network. If their initial values of RoCoF are to be the same, generally speaking, the virtual inertia value should be less than the equivalent inertia of the distribution network synchronous machine. To ensure the condition that the power disturbance distribution is proportional to the inertia, at this time, the values of each virtual inertia parameter need to be continuously increased, resulting in the equivalent inertia value at the point of common coupling being greater than the inertia command target value.

[0117] The embodiments of the present application can be used for multi-machine inertia coordinated control within the substation area. While meeting the requirements of the equivalent inertia command value at the point of common coupling, it effectively suppresses the dispersion of the frequency response of the equipment within the substation area, improves the stability and coordination of the system operation, and provides an important reference for the optimal allocation of inertia resources in the power system.

[0118] The inertia coordinated control method for the multi-virtual synchronous machine system in the distribution network substation area proposed according to the embodiments of the present application, based on the network node inertia equivalent model and combined with the adjustable characteristics of virtual inertia, proposes a multi-machine inertia coordinated control strategy for the distribution network substation area. While ensuring the inertia support requirements at the grid connection point, it significantly suppresses the dispersion of frequency responses among the internal devices in the substation area, and has important guiding value for the optimal allocation of inertia resources in the power system. Thus, it solves the problem that existing research mainly focuses on the design of single-machine virtual inertia control strategies, ignoring the coordination problem of inertia support capabilities in the scenario of multi-machine systems. At present, most research on inertia control is for single-machine systems, and there is less research on inertia control strategies for multi-machine systems and multi-substation area networks. Moreover, related technologies have strong dependence on adjacent node information and communication coupling, resulting in certain limitations in terms of reliability, dynamic adaptability, and large-scale expansion.

[0119] Next, a description is given with reference to the drawings of an inertia coordinated control device for a multi-virtual synchronous machine system in a distribution network substation area proposed according to the embodiments of the present application.

[0120] Figure 2 It is a schematic structural diagram of an inertia coordinated control device for a multi-virtual synchronous machine system in a distribution network substation area according to an embodiment of the present application.

[0121] As Figure 2 shown, the inertia coordinated control device 10 for the multi-virtual synchronous machine system in the distribution network substation area includes: an acquisition module 100, a generation module 200, and a collaborative optimization module 300.

[0122] Specifically, the acquisition module 100 is configured to acquire the device dynamic characteristics and line impedance of the system in the multi-virtual synchronous machine system in the distribution network substation area.

[0123] The generation module 200 is configured to generate an optimal configuration of the device inertia parameters of each device in the system according to the device dynamic characteristics and line impedance, so as to dynamically adjust the magnitude and distribution of the inertia of each device.

[0124] The collaborative optimization module 300 is configured to perform collaborative optimization based on the optimal configuration of the device inertia parameters of each device and in combination with the parameters of the adjustable units within the substation area.

[0125] Optionally, in an embodiment of the present application, the generation module 200 includes: an acquisition unit and a calculation unit.

[0126] Among them, the acquisition unit is configured to acquire the inertia parameters of each generator and virtual synchronous machine device and the line impedance based on the network node inertia equivalent model.

[0127] The calculation unit is configured to calculate the inertia at the grid connection point of the target substation area according to the inertia parameters of each generator and virtual synchronous machine device and the line impedance.

[0128] Optionally, in an embodiment of the present application, the inertia coordination control device 10 of the distribution network substation multi-virtual synchronous machine system further includes: a change rate acquisition module and an adjustment value acquisition module.

[0129] Among them, the change rate acquisition module is used to acquire the initial instantaneous frequency change rate of each unit after disturbance.

[0130] The adjustment value acquisition module is used to obtain the adjustment values of the inertia and damping parameters of the virtual inertia control based on the preset control strategy and using the initial instantaneous frequency change rate of each unit after disturbance.

[0131] Optionally, in an embodiment of the present application, the dynamic response formula of the unit frequency of each unit is:

[0132]

[0133] Among them, f is the unit frequency, H is the unit virtual inertia constant, and D is the damping coefficient.

[0134] Optionally, in an embodiment of the present application, the first device inertia configuration formula of each device is:

[0135]

[0136] Among them, i is the unit, H PCC is the inertia at the grid connection point, T G-PCC,i is the power distribution coefficient between the generator i and the grid connection point, S sys is the system capacity, S G is the generator capacity.

[0137] Optionally, in an embodiment of the present application, the second device inertia configuration formula of each device is:

[0138]

[0139] Among them, T PCC-grid is the power distribution coefficient of the upper main grid at the grid connection point, T grid-PCC =T PCC-grid is the power distribution coefficient between the generator i and the grid connection point, H PCC is the inertia at the grid connection point, S sys is the system capacity, H grid is the equivalent inertia, S grid is the equivalent distribution network generator inertia, S G is the generator capacity.

[0140] It should be noted that the foregoing explanation of the embodiment of the inertia coordination control method for the distribution network substation multi-virtual synchronous machine system also applies to the inertia coordination control device of the distribution network substation multi-virtual synchronous machine system in this embodiment, and will not be elaborated here.

[0141] According to the inertia coordinated control device of the multi-virtual synchronous machine system in the distribution network substation area proposed in the embodiments of the present application, based on the network node inertia equivalent model and combined with the adjustable characteristics of virtual inertia, a multi-machine inertia coordinated control strategy for the distribution network substation area is proposed. While ensuring the inertia support requirements at the grid connection point, it significantly suppresses the dispersion of frequency responses among internal devices in the substation area, which has important guiding value for the optimal allocation of inertia resources in the power system. Thus, it solves the problem that existing research mainly focuses on the design of single-machine virtual inertia control strategies, ignoring the coordination problem of inertia support capabilities in the multi-machine system scenario. Moreover, most current research on inertia control is for single-machine systems, and there is less research on inertia control strategies for multi-machine systems and multi-substation area networks. Additionally, related technologies have strong dependence on adjacent node information and communication coupling, resulting in certain limitations in terms of reliability, dynamic adaptability, and large-scale expansion.

[0142] Figure 3 The structural schematic diagram of the electronic device provided by the embodiments of the present application. The electronic device may include:

[0143] A memory 301, a processor 302, and a computer program stored on the memory 301 and executable on the processor 302.

[0144] When the processor 302 executes the program, it implements the inertia coordinated control method for the multi-virtual synchronous machine system in the distribution network substation area provided in the above embodiments.

[0145] Furthermore, the electronic device further includes:

[0146] A communication interface 303 for communication between the memory 301 and the processor 302.

[0147] The memory 301 is used to store a computer program executable on the processor 302.

[0148] The memory 301 may include a high-speed RAM memory, and may also include non-volatile memory, such as at least one disk memory.

[0149] If the memory 301, the processor 302, and the communication interface 303 are implemented independently, the communication interface 303, the memory 301, and the processor 302 can be interconnected through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 3 only a thick line is used to represent it in Figure 3 , but it does not mean that there is only one bus or one type of bus.

[0150] Optionally, in a specific implementation, if the memory 301, the processor 302, and the communication interface 303 are integrated on a single chip, the memory 301, the processor 302, and the communication interface 303 can communicate with each other through an internal interface.

[0151] The processor 302 may be a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0152] This embodiment also provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the inertia coordination control method of the multi-virtual synchronous machine system in the distribution network substation area as described above is implemented.

[0153] The embodiments of the present application also provide a computer program product, on which a computer program is stored, and when the program is executed by a processor, the inertia coordination control method of the multi-virtual synchronous machine system in the distribution network substation area as described above is implemented.

[0154] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0155] In addition, the terms "first" and "second" are used only for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0156] Any process or method description shown in the flowchart or described in other ways herein may be understood to represent a module, segment, or portion of code including one or N executable instructions for implementing a customized logical function or process, and the scope of the preferred embodiments of this application includes additional implementations, where the functions may be executed in a manner that is not in the order shown or discussed, including in a substantially simultaneous manner according to the involved functions or in a reverse order, which should be understood by those skilled in the art to which the embodiments of this application belong.

[0157] The logic and / or steps represented in the flowchart or otherwise described herein can, for example, be considered as a definitional sequence list of executable instructions for implementing logical functions, which can be embodied specifically in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or used in conjunction with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection portion (electronic device) having one or N wirings, a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other media, followed by editing, interpretation, or otherwise processing as appropriate, and then stored in a computer memory.

[0158] It should be understood that various parts of the present application can be implemented by hardware, software, firmware, or a combination thereof. In the above-described embodiments, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), and the like.

[0159] Those of ordinary skill in the art of this technology can understand that all or part of the steps carried by the method of the above embodiments can be completed by a program instructing relevant hardware, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0160] In addition, each functional unit in various embodiments of the present application may be integrated into one processing module, or each unit may exist physically alone, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0161] The above-mentioned storage medium may be a read-only memory, a magnetic disk, an optical disc, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A method for inertial coordinated control of a multi-virtual synchronous machine system in a distribution network substation area, characterized in that, It includes the following steps: In the multi-virtual synchronous machine system of the distribution network substation area, obtain the device dynamic characteristics and line impedance of the system; Generate the optimal configuration of the device inertia parameters of each device in the system according to the device dynamic characteristics and line impedance, so as to dynamically adjust the magnitude and distribution of the inertia of each device; Based on the optimal configuration of the device inertia parameters of each device, combine the parameters of the adjustable units inside the substation area for collaborative optimization.

2. The method according to claim 1, wherein The generating the optimal configuration of the device inertia parameters of each device in the system according to the device dynamic characteristics and line impedance includes: Based on the network node inertia equivalent model, obtain the inertia parameters of each generator and virtual synchronous machine device and the line impedance; Calculate the inertia at the connection point of the target substation area according to the inertia parameters of each generator and virtual synchronous machine device and the line impedance.

3. The method according to claim 2, wherein It also includes: Obtain the initial instantaneous frequency change rate of each unit after the disturbance; Based on the preset control strategy, use the initial instantaneous frequency change rate of each unit after the disturbance to obtain the adjustment values of the inertia and damping parameters of the virtual inertia control.

4. The method according to claim 3, wherein The dynamic response formula of the unit frequency of each unit is: Wherein, f is the unit frequency, H is the virtual inertia constant of the unit, and D is the damping coefficient.

5. The method according to claim 1, characterized in that, The first device inertia configuration formula of each device is: Among them, i is the unit, H PCC is the inertia at the grid connection point, T G-PCC,i is the power distribution coefficient between generator i and the grid connection point, S sys is the system capacity, S G is the generator capacity.

6. The method according to claim 5, wherein The second device inertia configuration formula of each device is: Among them, T PCC-grid is the power distribution coefficient of the upper main grid at the grid connection point, T grid-PCC = T PCC-grid is the power distribution coefficient between the generator i and the grid connection point, H PCC is the inertia of the grid connection point, S sys is the system capacity, H grid is the equivalent inertia, S grid is the equivalent inertia of the distribution network generator, S G is the capacity of the generator.

7. An inertia coordinated control device for a multi-virtual synchronous machine system in a distribution network substation area, characterized in that, It includes: An acquisition module, used to obtain the device dynamic characteristics and line impedance of the system in the multi-virtual synchronous machine system of the distribution network substation area; A generation module, used to generate the optimal configuration of the device inertia parameters of each device in the system according to the device dynamic characteristics and line impedance, so as to dynamically adjust the magnitude and distribution of the inertia of each device; A collaborative optimization module, used to perform collaborative optimization based on the optimal configuration of the device inertia parameters of each device and combine the parameters of the adjustable units inside the substation area.

8. An electronic device, characterized in that, It includes: A memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor executes the program to implement the inertia coordination control method for the multi-virtual synchronous machine system of the distribution network substation area according to any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to be used to implement the inertia coordination control method for the multi-virtual synchronous machine system of the distribution network substation area according to any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that, The computer program is executed to be used to implement the inertia coordination control method for the multi-virtual synchronous machine system of the distribution network substation area according to any one of claims 1-6.

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