New Energy Inertia Enhancement Control Method and System for Improving the Self-Healing Capability of Distribution Networks

Abstract

This application provides a new energy inertial enhancement control method and system for improving the self-healing capability of distribution networks. The method includes: determining the energy storage configuration target of the new energy power station; determining the representative power value of the new energy power station based on historical output power data; configuring virtual synchronous controller parameters; calculating the energy storage power capacity required for the energy storage system to meet inertial support and primary frequency regulation based on the energy storage configuration target, the representative power value, and the virtual synchronous controller parameters; calculating the energy storage capacity of the energy storage system based on the energy storage power capacity; configuring the energy storage system according to the energy storage capacity and connecting it to the new energy power station; and responding to grid disturbances through the virtual synchronous controller to support the self-healing operation of the distribution network. The technical solution provided by this invention can adapt to the dynamic needs in the distribution network self-healing process, ensuring the stable operation and rapid recovery of the distribution network under complex disturbances.

Description

Technical Field

[0001] This invention belongs to the field of power distribution network self-healing technology, and in particular relates to a new energy inertia enhancement control method and system for improving the self-healing capability of power distribution networks. Background Technology

[0002] As the global energy structure shifts towards clean energy, large-scale wind power, photovoltaic, and other new energy units are continuously replacing traditional synchronous generators in the distribution network. While promoting the greening of energy supply, this also poses a significant challenge to the self-healing capability of the distribution network. The core of the distribution network's self-healing capability lies in its ability to quickly isolate faulty areas, balance power supply and demand, and restore power to critical loads when the system encounters a fault or disturbance. However, the high penetration rate of new energy sources is gradually weakening the underlying support mechanism for this process.

[0003] Traditional synchronous generator units can naturally suppress frequency surges due to rotor inertia, and their speed governors can dynamically adjust output power based on frequency deviations, providing a stable frequency environment for self-healing operations such as distribution network fault isolation and load transfer. However, new energy generator units are connected to the grid through power electronic converters, decoupled from the system frequency. They lack inherent inertia to withstand drastic frequency fluctuations and, due to their long-term operation in maximum power point tracking mode, lack active power reserve regulation capabilities. When disturbances such as line faults or load surges occur in the distribution network, the system struggles to quickly smooth out power imbalances, and frequency deviations can easily exceed the allowable range of self-healing control, leading to an expansion of the fault area or failure of the self-healing strategy.

[0004] To compensate for the regulation deficiencies of renewable energy units, existing technologies attempt to provide temporary inertial support by releasing the kinetic energy of the wind turbine rotor, or to reserve active power for power regulation. However, the former leads to a sharp drop in wind turbine speed, which may cause a secondary frequency drop during the recovery process, exacerbating distribution network instability; the latter comes at the cost of sacrificing renewable energy utilization, contradicting the goal of efficient use of clean energy. Although energy storage devices are used to enhance frequency support capabilities, current configurations and control schemes mostly focus on a single frequency stability indicator, failing to quantify the synergistic relationship between inertial support and power regulation in conjunction with the self-healing needs of the distribution network. Furthermore, they are insufficiently adapted to the randomness of renewable energy output, making it difficult to provide accurate and reliable support in self-healing stages such as fault isolation and load restoration. This results in a significant decrease in the self-healing response speed and success rate of the distribution network under high renewable energy penetration.

[0005] Therefore, in order to address the issues of reduced equivalent inertia and insufficient power regulation capability of distribution networks after the integration of new energy sources, there is an urgent need for a new energy inertia enhancement control method and system to improve the self-healing capability of distribution networks, so as to adapt to the dynamic needs in the self-healing process of distribution networks and ensure the stable operation and rapid recovery of distribution networks under complex disturbances. Summary of the Invention

[0006] The embodiments of this application provide a new energy inertial enhancement control method and system for improving the self-healing capability of distribution networks. It can adapt to the dynamic needs in the self-healing process of distribution networks and ensure the stable operation and rapid recovery of distribution networks under complex disturbances.

[0007] In a first aspect, embodiments of this application provide a new energy inertia enhancement control method for improving the self-healing capability of distribution networks, including:

[0008] Determine the energy storage configuration targets for new energy power plants;

[0009] The representative power value of the new energy power station is determined based on the historical output power data of the new energy power station;

[0010] Determine the parameters of the virtual synchronous controller and configure the virtual synchronous controller to enable the new energy power plant to simulate the inertial response and primary frequency regulation characteristics of a synchronous generator;

[0011] Based on the energy storage configuration target, and using representative power values ​​and virtual synchronous controller parameters, the energy storage power capacity required for the energy storage system of the new energy power station to meet inertial support and primary frequency regulation is calculated respectively.

[0012] Calculate the energy storage capacity of the energy storage system based on its energy storage power capacity;

[0013] Configure energy storage systems according to energy storage capacity, connect new energy power plants with configured energy storage systems to the distribution network, and respond to grid disturbances through virtual synchronization controllers to support the self-healing operation of the distribution network.

[0014] In one alternative implementation, the energy storage configuration objectives include:

[0015] Calculate the current system equivalent inertia constant and power-frequency ratio coefficient of the new energy power plant, and take maintaining the system equivalent inertia constant and power-frequency ratio coefficient unchanged as the energy storage configuration target.

[0016] In one optional implementation, the representative power value of the new energy power station is determined based on historical output power data, including:

[0017] An empirical cumulative distribution function is constructed based on the historical output power data of new energy power plants;

[0018] The corresponding power per-unit value is determined from the empirical cumulative distribution function based on a set confidence level;

[0019] The representative power value is obtained based on the per-unit power value and the rated capacity of the new energy power plant.

[0020] In one alternative implementation, based on the energy storage configuration target, the energy storage capacity required for the energy storage system of the new energy power station to meet inertial support is calculated using a representative power value. The calculation formula is as follows:

[0021]

[0022] Among them, S ESS1 H represents the energy storage capacity required by the energy storage system to meet inertial support requirements. ESS H represents the inertia coefficient of energy storage. eq P represents the system's equivalent inertial constant. Wα f represents the representative power value. N This represents the system's rated frequency, and K represents the controller coefficient.

[0023] In one optional implementation, based on the energy storage configuration target and representative power values, the energy storage capacity required by the energy storage system of the new energy power station to meet primary frequency regulation is calculated, using the following formula:

[0024] S ESS2 =R ESS ·f N ·(λ0-λ1);

[0025]

[0026] Among them, S ESS2 R represents the energy storage capacity required by the energy storage system to meet primary frequency regulation. ESS f represents the droop coefficient. N R represents the system's rated frequency, λ0 represents the power-frequency ratio coefficient of the system before generator replacement, λ1 represents the power-frequency ratio coefficient of the system after generator replacement, and R pu This represents the per-unit value of the droop coefficient, Δf. pu ΔP represents the per-unit value of the frequency deviation. pu Δf represents the per-unit value of power change, and Δf represents the frequency change.

[0027] In one optional implementation, calculating the energy storage capacity of the energy storage system based on the energy storage power capacity includes:

[0028] Calculate the inertial response energy based on the energy storage power capacity required by the energy storage system to meet inertial support requirements;

[0029] Calculate the primary frequency regulation energy based on the energy storage power capacity required by the energy storage system to meet the primary frequency regulation;

[0030] The larger value between the inertial response energy and the primary frequency regulation energy is selected as the energy storage capacity of the energy storage system.

[0031] In one optional implementation, the inertial response energy is calculated based on the energy storage power capacity required by the energy storage system to meet inertial support, using the following formula:

[0032]

[0033] Among them, E ESS1 Let t1 represent the initial moment of the inertial response, t2 represent the moment when the frequency fluctuation reaches its lowest or highest point, and K represent the controller coefficient. S represents the rate of change of frequency. ESS1 This indicates the energy storage power capacity required by the energy storage system to meet inertial support requirements.

[0034] In one optional implementation, the primary frequency regulation energy is calculated based on the energy storage power capacity required by the energy storage system to meet the primary frequency regulation requirements, using the following formula:

[0035] E ESS2 =1.2·(t) dis ·S ESS2 +t ch ·S ESS2 );

[0036] Among them, E ESS2 t represents the primary frequency modulation energy. dis The duration of energy storage participating in a primary frequency-modulated discharge is indicated by t. ch S represents the duration of energy storage participating in a single frequency regulation charging cycle. ESS2 This indicates the energy storage power capacity required by the energy storage system to meet primary frequency regulation.

[0037] Secondly, embodiments of this application provide a new energy inertial enhancement control system for improving the self-healing capability of power distribution networks, comprising:

[0038] The configuration target determination module is used to determine the energy storage configuration target of new energy power plants;

[0039] The representative power value calculation module is used to determine the representative power value of a new energy power plant based on its historical output power data.

[0040] The virtual synchronous controller configuration module is used to determine the parameters of the virtual synchronous controller and configure the virtual synchronous controller so that the new energy power plant can simulate the inertial response and primary frequency regulation characteristics of a synchronous generator.

[0041] The energy storage power capacity calculation module is used to calculate the energy storage power capacity of the energy storage system of the new energy power station to meet inertial support and primary frequency regulation, respectively, based on the energy storage configuration target, representative power value and virtual synchronous controller parameters.

[0042] The energy storage capacity calculation module is used to calculate the energy storage capacity of the energy storage system of the new energy power station based on the energy storage power capacity.

[0043] The verification module is used to configure the energy storage system according to the energy storage capacity, connect the new energy power station with the configured energy storage system to the distribution network, and respond to grid disturbances through a virtual synchronization controller to support the self-healing operation of the distribution network.

[0044] Thirdly, embodiments of this application provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the method provided in embodiments of this application.

[0045] Fourthly, embodiments of this application provide a computer-readable storage medium, characterized in that it stores a computer program thereon, which, when executed in a computer, causes the computer to perform the method provided in embodiments of this application.

[0046] The technical solution provided in this application uses virtual synchronous control technology to dynamically simulate the inertia and primary frequency regulation characteristics of a synchronous generator in a new energy power plant. This ensures that the system's equivalent inertia constant and power-frequency ratio remain unchanged during the replacement of traditional units by new energy sources. This effectively suppresses frequency spikes in the early stages of disturbances (such as line faults or load spikes), prevents frequency deviations from exceeding the allowable range of self-healing control, and provides a stable frequency environment for self-healing operations such as fault isolation and load transfer. Furthermore, by determining representative power values ​​based on historical data statistical methods, the energy storage capacity configuration is precisely adapted to the fluctuations in new energy output, avoiding the need for... With sufficient redundancy or insufficiency, energy storage systems can provide rapid power support (such as suppressing frequency drops) and energy buffering (such as supporting load recovery) during faults, while significantly reducing investment costs and improving energy storage utilization and system reliability. The combination of virtual synchronization control maintaining system stability and optimized energy storage providing flexibility forms a dual-track synergy. In the early stages of disturbances, inertial response suppresses frequency abrupt changes; during fault recovery, primary frequency regulation and energy storage balance power supply and demand. This method systematically improves the resilience of the distribution network from disturbance resistance to recovery, shortens self-healing response time, and increases the success rate of fault isolation and power restoration. Attached Figure Description

[0047] Figure 1 This is a flowchart illustrating a new energy inertia enhancement control method for improving the self-healing capability of a distribution network, provided in an embodiment of this application.

[0048] Figure 2 This is a block diagram of energy storage inertia and primary frequency regulation control provided in an embodiment of this application;

[0049] Figure 3 This is a graph showing the primary frequency regulation output power of energy storage under different power deficit conditions, provided in an embodiment of this application.

[0050] Figure 4This is a schematic diagram of the structure of a new energy inertial enhancement control system for improving the self-healing capability of a power distribution network, provided in an embodiment of this application. Detailed Implementation

[0051] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] Figure 1 This is a flowchart illustrating a new energy inertia enhancement control method for improving the self-healing capability of a distribution network, provided in an embodiment of this application. The method can be executed by a new energy inertia enhancement control device for improving the self-healing capability of a distribution network. The device can be implemented by software and / or hardware and can be configured in electronic devices such as computers.

[0053] Among them, a new energy power station is a collection of multiple new energy power stations (such as wind turbine generators or photovoltaic power generation units), for example, a wind power station or a photovoltaic power station. New energy power stations are an important part of the distribution network, but their output has inherent fluctuations (due to changes in wind speed or sunlight), resulting in the actual load they can bear being lower than their installed capacity. Although new energy power stations can provide clean energy, they lack the inertial support and primary frequency regulation capability of traditional synchronous generators, which affects the self-healing capability of the distribution network (such as increased frequency fluctuations during faults).

[0054] The energy storage system of a new energy power station is an independently configured auxiliary device used to provide power support and energy buffering for the new energy power station. The new energy power station is the main power generation unit, and the energy storage system is an auxiliary facility to enhance its stability. The two are physically separated but functionally complementary. The energy storage system and the new energy power station achieve dynamic coordination through a virtual synchronous controller. The connection point of the new energy power station to the grid is called the "grid connection point". The instantaneous power state of the local power grid where the new energy power station is located is determined according to the real-time frequency of this node. The virtual synchronous controller uses the real-time frequency of the grid connection point as the control input, responds to grid disturbances, generates corresponding power commands according to the real-time frequency and frequency change rate, and outputs them to the energy storage system. The energy storage system performs power compensation based on the power commands to support the self-healing of the distribution network.

[0055] like Figure 1 As shown, the technical solution provided in this application includes the following steps:

[0056] S110. Determine the energy storage configuration targets for new energy power plants.

[0057] In one implementation, the current system equivalent inertia constant and power-frequency scaling factor of the new energy power plant are first calculated. The inertia constant H of a single synchronous generator is defined as:

[0058]

[0059] Among them, EkN S represents the rotational energy of the generator rotor at its rated speed. N J represents the rated capacity of the generator, ω represents the moment of inertia of the generator rotor. N This indicates the generator's rated speed.

[0060] Based on this, the equivalent inertial constant H of a system containing n power generation units eq The calculation formula is as follows:

[0061]

[0062] Among them, H i S represents the inertial constant of the i-th power generation unit. Ni S represents the rated capacity of the i-th power generation unit. sys This indicates the total installed capacity of the system.

[0063] Based on the generator rotor motion equations, the relationship between the equivalent inertial constant and the initial frequency change rate of a system composed of multiple generator units can be derived:

[0064]

[0065] Among them, f N ΔP represents the system's rated frequency, ΔP represents the system's unbalanced power, and f represents the system frequency.

[0066] When there are multiple power generation units in the system, the unbalanced power ΔP and the steady-state frequency error Δf can be derived from the droop coefficient of each unit. ss Definition of proportionality coefficient λ:

[0067]

[0068] Among them, R i This represents the droop coefficient of the speed governor of the i-th power generation unit.

[0069] When the unbalanced power of the system is the same, the larger λ is, the smaller the degree of frequency deviation from the rated value and the better the frequency transient stability of the system. However, the requirements for the primary frequency regulation reserve capacity of the system are also higher.

[0070] In this embodiment, after energy storage is configured, the system's equivalent inertia constant should not be too large or too small. If the system's equivalent inertia is too large, the grid frequency recovery speed will be very slow; if the equivalent inertia is too small, the grid frequency will drop or rise rapidly when power imbalance occurs, failing to meet the system's operating df / dt requirements. Considering that the power system has good stability under the inertia of traditional synchronous generator sets, this method targets the regional grid inertia, aiming to ensure that the system's equivalent inertia time constant remains unchanged after the new energy power station is connected to the system.

[0071] Primary frequency regulation is a type of differential regulation, and its deviation is jointly determined by the power imbalance, the droop coefficient, and the system power. Therefore, in order to prevent the degradation of the primary frequency regulation performance of the power grid, this invention aims to maintain the system's equivalent inertia constant and the power-frequency ratio constant as the energy storage configuration objective.

[0072] With new energy sources gradually replacing traditional synchronous generators in the grid, maintaining grid stability has become a core challenge. The system equivalent inertia constant reflects the grid's inherent ability to resist frequency abrupt changes; essentially, it is the comprehensive proportional relationship between the kinetic energy stored in all rotating units and the total installed capacity. The physical significance of this parameter lies in the fact that when power imbalance occurs in the grid, a higher equivalent inertia constant can significantly slow down the rate of frequency change, providing a critical time window for subsequent control measures. The power-frequency ratio coefficient, on the other hand, characterizes the power regulation capability corresponding to a unit frequency deviation in the system, and its magnitude directly determines the accuracy with which the grid recovers its steady-state frequency after a disturbance. The synergistic effect of these two parameters constitutes the cornerstone of grid frequency stability. Especially during distribution network self-healing, a stable frequency environment is a prerequisite for rapid fault isolation and effective load restoration.

[0073] S120. Determine the representative power value of the new energy power station based on the historical output power data of the new energy power station.

[0074] Unlike traditional synchronous generator sets, grid-connected renewable energy power plants operate at off-rated power output for most of the year due to the randomness of wind speed and photovoltaic fluctuations, resulting in a system load lower than the rated power of the renewable energy power plant. Therefore, configuring energy storage based on the actual annual output of the renewable energy power plant is more economical and improves energy storage utilization compared to configuring energy storage based on the installed capacity of the renewable energy plant.

[0075] In this embodiment, S120 specifically includes the following sub-steps:

[0076] S121. Construct an empirical cumulative distribution function based on the historical output power data of new energy power plants.

[0077] S122. Determine the corresponding power per unit value from the empirical cumulative distribution function based on the set confidence level.

[0078] S123. Obtain representative power values ​​based on per-unit power values ​​and the rated capacity of new energy power plants.

[0079] In one implementation, an empirical cumulative distribution function is constructed based on the historical output power data of the new energy power plant, and its definition is as follows:

[0080]

[0081] Where N represents the number of samples of historical output power data of new energy power plants, j represents the j-th sample, P* represents the power per unit value, and x j F represents the per-unit power value of the j-th sample. N (P*) represents the probability that the per-unit power of the sample is less than or equal to P*, I{x j ≤P*} is an indicator function used to count the number of samples whose per-unit power value is less than or equal to P*.

[0082] In one implementation, to improve the economic efficiency of energy storage configuration, a confidence level α for the output power of the new energy power plant is set, and the corresponding per-unit power value P is determined based on the empirical cumulative distribution function. α * The confidence level reflects the required reliability of renewable energy output. For example, a higher level corresponds to stricter guarantee requirements. The confidence level α can be set according to actual conditions, such as a 95% confidence level. When a higher confidence level is selected, the resulting per-unit value will cover the vast majority of historical operating conditions, ensuring that the energy storage configuration can cope with extreme fluctuation scenarios.

[0083] In one implementation, a representative power value is obtained based on the per-unit power value and the rated capacity of the new energy power plant. The calculation formula is as follows:

[0084]

[0085] Among them, S W Indicates the rated capacity of the new energy power station. This represents the representative power value. The physical meaning is: at confidence level α, the output power of the new energy power station is... The following, new energy power plants will undertake the system The following active load will replace The capacity synchronous generator set provides inertial and primary frequency regulation support.

[0086] S130. Determine the parameters of the virtual synchronous controller and configure the virtual synchronous controller to enable the new energy power station to simulate the inertial response and primary frequency regulation characteristics of a synchronous generator.

[0087] In this embodiment, the virtual synchronization controller parameters include controller coefficients and droop coefficients.

[0088] In one implementation, drawing an analogy to the relationship between the system's equivalent inertial constant and the rate of change of the initial frequency, and ignoring delays in frequency measurement and other processes, the expression for the energy storage inertial coefficient is:

[0089]

[0090] Among them, f NIndicates the system's rated frequency, H ESS The inertia coefficient represents the energy storage.

[0091] Within the energy storage power limit, the larger the controller coefficient, the greater the energy storage inertia. However, due to the limitation of ±1 pu in the energy storage output power, an excessively high K will result in an inertia smaller than the calculated value.

[0092] In some embodiments, to ensure that the inertia constant of the energy storage remains unchanged under any unbalanced conditions, df / dt typically does not exceed 0.5 Hz / s according to power operation requirements. Based on the power ±1 pu limiting requirement, the controller coefficient K should not exceed 2. According to the expression for the energy storage inertia coefficient, the maximum inertia time constant of the energy storage device can be obtained as 50 s. To ensure a 20% margin in the energy storage output power, the formula for calculating the controller coefficient is as follows:

[0093]

[0094] Based on this, the controller coefficient K is set to 1.667.

[0095] In one implementation, the primary frequency modulation dead zone in this embodiment is set to 49.98–50.02 Hz. According to relevant standards, within the frequency range of 49.8–50.2 Hz, the primary frequency modulation of energy storage exhibits linear variation, and the power supply for primary frequency modulation must provide frequency support for at least 15 minutes. Based on the linear frequency adjustment within the 49.8–50.2 Hz range and the dead zone of 49.98–50.02 Hz, the droop coefficient R can be calculated. ESS =0.0036.

[0096] The specific calculation process is as follows:

[0097] When the frequency falls below the dead zone lower limit (49.98Hz), the energy storage begins to increase its output power (discharge). When the frequency reaches 49.8Hz, the energy storage output power reaches its maximum value +1pu (i.e., full power discharge). Therefore, the frequency change from the dead zone lower limit to the frequency lower limit is:

[0098] Δf=49.98Hz-49.8Hz=0.18Hz;

[0099] The corresponding power change is ΔP = 1pu (from 0 to +1pu);

[0100] The per-unit value of frequency deviation is calculated as follows:

[0101]

[0102] Substituting into the formula for calculating the droop coefficient, we get:

[0103]

[0104] Among them, R pu This represents the per-unit value of the droop coefficient, Δf. pu ΔP represents the per-unit value of the frequency deviation. pu Δf represents the per-unit value of power change, and Δf represents the frequency change.

[0105] Therefore, the droop coefficient R ESS =0.0036 is a per-unit value, which means that a frequency change of 0.0036 pu (i.e. 0.18 Hz) will cause a change of 1 pu in energy storage power.

[0106] In one implementation, since the time for energy storage to participate in the system's primary frequency regulation is relatively long, energy-type energy storage is generally selected, which has limited response speed and ramp-up speed. Therefore, ramp-up rate limits also need to be set.

[0107] Configure a virtual synchronous controller to enable the new energy power plant to simulate the inertial response and primary frequency regulation characteristics of a synchronous generator. Figure 2 This is a block diagram of energy storage inertia and primary frequency regulation control provided in an embodiment of this application. See also... Figure 2 In this embodiment, the virtual synchronization controller adopts a strategy combining inertial control and droop control. The control process is as follows:

[0108] 1. Input signal: The actual frequency f of the system is the control input quantity, and f is the measured value.

[0109] 2. Frequency Differential Component: This component calculates the rate of change of frequency, df / dt. df / dt is a key indicator for measuring the speed at which frequency decreases or increases. A negative df / dt with a large absolute value means that the frequency is decreasing rapidly, indicating a large power deficit in the power grid.

[0110] 3. The virtual synchronous controller includes two branches: an inertial control branch and a primary frequency modulation control branch;

[0111] In the inertial control branch: proportional control is used, multiplying the frequency change rate df / dt by the controller coefficient K to simulate the physical inertia of the synchronous generator. A larger K value means greater "sensitivity" to the rate of frequency change and a more drastic response, effectively giving the system a larger "virtual inertia" (i.e., the energy storage inertia coefficient H). ESS The output of this branch is a power command (K×df / dt), the purpose of which is to provide instantaneous power support proportional to the rate of frequency change in order to quickly suppress the initial rate of frequency decline.

[0112] In a primary frequency modulation control branch: control is performed using a primary frequency modulation dead zone and droop control.

[0113] If the frequency f falls within the very small normal range of 49.98Hz to 50.02Hz, the output of this circuit is 0. This is to avoid frequent operation of the energy storage when the grid frequency fluctuates normally, reducing unnecessary charge-discharge cycles and extending its lifespan. The droop coefficient is determined based on the primary frequency regulation dead zone. When the frequency deviation Δf exceeds the dead zone, the droop coefficient R begins to operate. It provides a power command proportional to the magnitude of the frequency deviation (not the rate of change). The droop coefficient determines "how much frequency deviation the energy storage needs to deliver full power." The output of this branch is a power command, the purpose of which is to provide continuous power support proportional to the magnitude of the frequency deviation, helping the frequency recover to near its rated value.

[0114] 4. Add the power commands generated by the inertial control and primary frequency modulation control branches to obtain the total power command P. ESS * (P ESS * It is a per-unit value, with the reference being the energy storage's own power capacity S. ESS ).

[0115] Setting a power limit: This restricts the total power command to the range that the energy storage converter (PCS) can handle, i.e., -1 pu to +1 pu. For example, for 10 MW of energy storage, ±1 pu is ±10 MW. This step means that there is an upper limit to the energy storage output. The theoretical command generated by excessively high K or excessively low R may be clipped and cannot be fully realized.

[0116] Setting a ramp rate limit: This step limits the rate of change of power commands. Because of the chemical properties of energy storage systems (especially energy storage batteries), their power output cannot change instantaneously like electronic signals; a ramp-up process is required to avoid damaging the equipment.

[0117] 5. Final Output: The final instruction after all processing, multiplied by the energy storage capacity S. ESS The actual active power output value P is obtained. ESS It is then fed into the distribution network.

[0118] In this embodiment, without considering power limitations, the final energy storage output power P ESS The expression is:

[0119]

[0120] in, S represents the per-unit value of the energy storage inertial response. ESS This represents the energy storage capacity, and K represents the controller coefficient.

[0121] S140. Based on the energy storage configuration target, and using representative power values ​​and virtual synchronous controller parameters, calculate the energy storage power capacity required for the energy storage system of the new energy power station to meet inertial support and primary frequency regulation.

[0122] In this embodiment, after the new energy power station is connected to the grid, it lacks inertial response, and the system's equivalent inertial constant decreases. To ensure that the system's equivalent inertia remains unchanged before and after the new energy power station is connected, the new energy power station equipped with energy storage should have the same system equivalent inertial constant H as the system before connection. eq The configured energy storage system should provide the inertial energy required for the output of the new energy power station as follows:

[0123] H ESS ·S ESS =H eq ·P Wα ;

[0124] The higher the inertia coefficient of energy storage, the smaller the required energy storage capacity.

[0125] In one implementation, based on the determined controller coefficient K = 1.667, the system rated frequency f N =50Hz, according to the formula The inertia coefficient of the energy storage system can be determined to be 41.667 s (in seconds). Based on this, the energy storage power capacity required for the energy storage system of the new energy power station to meet inertial support can be calculated as follows:

[0126]

[0127] Among them, S ESS1 H represents the energy storage capacity required by the energy storage system to meet inertial support requirements. eq P represents the system's equivalent inertial constant. Wα f represents the representative power value. N This represents the system's rated frequency, and K represents the controller coefficient.

[0128] In this embodiment, after the new energy power station is connected to the grid, it replaces part of the synchronous generator set. Since the new energy power station lacks reserve capacity for primary frequency regulation, the steady-state frequency deviation of the grid's primary frequency regulation will increase, affecting the system's transient frequency stability. Therefore, the goal of configuring energy storage to improve primary frequency regulation performance is to maintain the system's power-frequency ratio λ unchanged after the new energy power station replaces the traditional synchronous generator set and is connected to the grid. This can be achieved by... The relationship between the power-frequency proportionality coefficient λ before and after the generator capacity is as follows:

[0129]

[0130] Therefore, the formula for calculating the energy storage capacity required for primary frequency regulation in the energy storage system of a new energy power station can be derived as follows:

[0131] S ESS2 =R ESS ·f N ·(λ0-λ1);

[0132] Among them, S ESS2 R represents the energy storage capacity required by the energy storage system to meet primary frequency regulation. ESS f represents the droop coefficient. N λ0 represents the system's rated frequency, λ1 represents the power-frequency ratio coefficient of the system before the generator was replaced, and λ1 represents the power-frequency ratio coefficient of the system after the generator was replaced.

[0133] Inertial support power capacity primarily addresses the millisecond to second-level dynamic process following a disturbance, its role being to slow down the rate of frequency change to buy time for standby units to start up. Primary frequency regulation power capacity, on the other hand, operates on the second to minute-level quasi-steady-state process, aiming to ultimately eliminate frequency deviation. This division of labor on this timescale requires that the two capacities be calculated independently rather than simply superimposed: the former depends on the system's tolerance threshold for the rate of frequency change, while the latter is related to the scale of the load disturbance and the accuracy of steady-state regulation. Under extreme conditions, the system may simultaneously face the dual pressures of high-frequency rate of change and large steady-state deviation. In this case, the two power capacities will work together, with the inertial support capacity prioritizing the suppression of the frequency drop rate, followed by the primary frequency regulation capacity taking over to complete the fine-tuning.

[0134] S150. Calculate the energy storage capacity of the energy storage system based on the energy storage power capacity.

[0135] In this embodiment, S150 specifically includes the following sub-steps:

[0136] S151. Calculate the inertial response energy based on the energy storage power capacity required by the energy storage system to meet inertial support.

[0137] S152. Calculate the primary frequency regulation energy based on the energy storage power capacity required by the energy storage system to meet the primary frequency regulation.

[0138] S153. Select the larger value between the inertial response energy and the primary frequency regulation energy as the energy storage capacity of the energy storage system.

[0139] In one implementation, it is based on the energy storage output power expression. Integrating both sides yields the formula for calculating the inertial response energy:

[0140]

[0141] Among them, E ESS1Let t1 represent the initial moment of the inertial response, t2 represent the moment when the frequency fluctuation reaches its lowest or highest point, and K represent the controller coefficient. S represents the rate of change of frequency. ESS1 This represents the energy storage power capacity required by the energy storage system to meet inertial support, and f1 and f2 are the system frequencies corresponding to t1 and t2, respectively.

[0142] The minimum and maximum points of system frequency variation differ under different operating conditions. In one implementation method, the most extreme case is selected; according to grid operation guidelines, the system frequency is allowed to fluctuate within the range of 51–48 Hz for short periods. The energy storage device must store an energy of E. ESS1_dis The energy is used to provide inertial support when the system has an active power deficit. The energy storage device must be able to absorb energy of magnitude E. ESS1_ch The energy is used to provide inertial support when the system has surplus active power.

[0143] Among them, E ESS1_dis This represents the discharge energy, addressing the frequency deficit, where the frequency drops from f1 = 50Hz to f2 = 48Hz, Δf dis =2Hz, the required discharge energy is: E ESS1_dis =K×S ESS1 ×Δf dis =1.667×S ESS1 ×2; E ESS1_ch This represents the charging energy, addressing the frequency deficit, as the frequency increases from f1 = 50Hz to f2 = 51Hz, Δf ch =1Hz, the required charging energy is: E ESS1_ch =K×S ESS1 ×Δf ch =1.667×S ESS1 ×1.

[0144] In one implementation, energy storage needs to satisfy both of the above extreme conditions simultaneously, therefore the total energy capacity is the sum of the two:

[0145] E ESS1 =E ESS1_dis +E ESS1_ch =1.667×S ESS1 ×3=5.001×S ESS1 .

[0146] In one implementation, considering the energy storage charge-discharge efficiency, a margin is set; for example, a 10% margin can be set, resulting in the following inertial response energy:

[0147] E ESS1 =5.5×S ESS1 ;

[0148] According to the formula It can also be expressed as:

[0149] E ESS1 =E ESS1_dis +E ESS1_ch =0.132(H) eq ·P Wα ).

[0150] In one implementation, the power variation of the primary frequency regulation output differs depending on the system frequency under different operating conditions. The curves of the primary frequency regulation output power of the energy storage system under different power deficits are as follows: Figure 3 As shown. When the power deficit is small (Case 1), the energy storage output power will not be saturated, and the output energy is relatively small. When the power deficit increases (Case 2), part of the energy storage output power will be in the nonlinear saturation region. When the power deficit is large (Case 3), due to the large frequency drop, the energy storage output power will remain in a saturated state, and the energy required for the energy storage output will be large.

[0151] Meanwhile, due to the complexity of the frequency response of a power system operating with multiple machines, changes in system frequency are difficult to describe using simple basic functions, making it difficult to measure the instantaneous output power of energy storage. To ensure the reliability of power system operation, this embodiment considers charging and discharging efficiency and energy storage state-of-charge limitations when designing energy storage for primary frequency regulation, setting a margin. For example, a 20% margin is selected. The calculation formula for the primary frequency regulation energy is as follows:

[0152] E ESS2 =1.2·(t) dis ·S ESS2 +t ch ·S ESS2 );

[0153] Among them, E ESS2 t represents the primary frequency modulation energy. dis The duration of energy storage participating in a primary frequency-modulated discharge is indicated by t. ch This indicates the duration for which the energy storage participates in a single frequency regulation charge; for example, it can be set to 15 minutes, S. ESS2 This indicates the energy storage capacity required by the energy storage system to meet primary frequency regulation; t dis ·S ESS2 Indicates full power S ES2S Discharge t dis Energy required for time, t ch ·S ESS2 Similarly.

[0154] Since the inertial response occurs in the early stage of the disturbance and the primary frequency regulation occurs in the recovery period, the two scenarios will not occur simultaneously. However, the energy storage must independently meet the peak energy demand of either scenario. Therefore, the larger value between the inertial response energy and the primary frequency regulation energy is taken as the energy storage capacity of the energy storage system.

[0155] By rationally configuring energy storage systems, the inertial response and primary frequency regulation capabilities of new energy power plants are effectively enhanced, thereby significantly improving the self-healing capability of the distribution network under high-proportion new energy access. This method not only synergistically optimizes energy storage capacity from both energy and power dimensions, but also improves the economy and reliability of configuration by considering the randomness of new energy output. This enables the distribution network to achieve power balance more quickly and suppress frequency fluctuations when faults occur, supporting fault isolation and rapid load recovery in non-faulty areas, fundamentally improving the stability and self-healing speed of the distribution network in response to disturbances.

[0156] S160. Configure an energy storage system according to the energy storage capacity, connect the new energy power station with the configured energy storage system to the distribution network, and respond to grid disturbances through a virtual synchronization controller to support the self-healing operation of the distribution network.

[0157] In one implementation, see Figure 2 In the initial stage of a disturbance, inertial control dominates. For example, if a fault causes a power deficit and a sudden frequency drop, the inertial control branch in the virtual synchronous controller outputs a power command (K×df / dt) based on the detected frequency change rate, controlling the energy storage system to perform power compensation and curb the frequency drop rate. The primary frequency regulation control branch outputs zero. During the fault recovery period, primary frequency regulation dominates. For example, after fault isolation, load loss leads to power excess, and the frequency remains below 50Hz. The primary frequency regulation control branch in the virtual synchronous controller outputs a power command based on the frequency change from the lower dead zone limit to the lower frequency limit, controlling the energy storage system to perform power compensation, continuously discharging to compensate for the power deficit. The inertial control branch outputs zero.

[0158] Figure 4 This is a schematic diagram of the structure of a new energy inertial enhancement control system for improving the self-healing capability of a distribution network, provided in an embodiment of this application. Figure 4 As shown, the system includes:

[0159] The configuration target determination module is used to determine the energy storage configuration target of new energy power plants;

[0160] The representative power value calculation module is used to determine the representative power value of a new energy power plant based on its historical output power data.

[0161] The virtual synchronous controller configuration module is used to determine the parameters of the virtual synchronous controller and configure the virtual synchronous controller so that the new energy power plant can simulate the inertial response and primary frequency regulation characteristics of a synchronous generator.

[0162] The energy storage power capacity calculation module is used to calculate the energy storage power capacity of the new energy power station energy storage system to meet inertial support and primary frequency regulation, respectively, based on the energy storage configuration target, representative power value and virtual synchronous controller parameters.

[0163] The energy storage capacity calculation module is used to calculate the energy storage capacity of the energy storage system of the new energy power station based on the energy storage power capacity.

[0164] The verification module is used to configure the energy storage system according to the energy storage capacity, connect the new energy power station to the distribution network, respond to grid disturbances through the virtual synchronization controller, and support the self-healing operation of the distribution network.

[0165] The execution process of the system part of this application embodiment is the same as that of the method part of the embodiment described above, and will not be repeated here.

[0166] This application also provides an electronic device, including: at least one processor; a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to execute any of the new energy-based power grid multi-resource coordinated control methods.

[0167] This application also proposes a computer storage medium storing a computer program, which, when executed by a processor, implements any one of the new energy-based power grid multi-resource coordinated control methods.

[0168] Computer storage media may be simply referred to as media. Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Dual Data SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), Rambus Direct RAM (RDRAM), Direct Memory Bus Dynamic RAM (DRDRAM), and Memory Bus Dynamic RAM (RDRAM). The various embodiments described in this specification are presented in a progressive manner, and similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, for embodiments of apparatus, devices, and non-volatile computer storage media, since they are substantially similar to the method embodiments, the description is relatively simple, and relevant parts can be referred to the description of the method embodiments.

[0169] The above embodiments are merely illustrative examples and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A new energy inertia enhancement control method for improving the self-healing capability of power distribution networks, characterized in that, include: Determine the energy storage configuration targets for new energy power plants; The representative power value of the new energy power station is determined based on the historical output power data of the new energy power station; Determine the parameters of the virtual synchronous controller, configure the virtual synchronous controller, and enable the new energy power station to simulate the inertial response and primary frequency regulation characteristics of a synchronous generator; Based on the energy storage configuration target, the energy storage power capacity required for the energy storage system of the new energy power station to meet inertial support and primary frequency regulation is calculated according to the representative power value and the virtual synchronous controller parameters. Calculate the energy storage capacity of the energy storage system based on the energy storage power capacity; Specifically, it includes: Calculate the inertial response energy based on the energy storage power capacity required by the energy storage system to meet inertial support requirements; The calculation formula is as follows: ； in, Let t1 represent the initial moment of the inertial response, t2 represent the moment when the frequency fluctuation reaches its lowest or highest point, and K represent the controller coefficient. Indicates the rate of change of frequency. This indicates the energy storage capacity required by the energy storage system to meet inertial support requirements; Calculate the primary frequency regulation energy based on the energy storage power capacity required by the energy storage system to meet the primary frequency regulation; The calculation formula is as follows: ； in, Indicates the primary frequency modulation energy. This indicates the duration of energy storage participation in a single frequency-modulated discharge. This indicates the duration for which energy storage participates in a single frequency regulation charging cycle. This indicates the energy storage capacity required by the energy storage system to meet primary frequency regulation; The larger value between the inertial response energy and the primary frequency modulation energy is selected as the energy storage capacity of the energy storage system. Configure the energy storage system according to the energy storage capacity, and connect the new energy power station with the configured energy storage system to the distribution network. The virtual synchronization controller responds to grid disturbances and supports the self-healing operation of the distribution network.

2. The method according to claim 1, characterized in that, The energy storage configuration objectives include: Calculate the current system equivalent inertia constant and power-frequency ratio coefficient of the new energy power plant, and take maintaining the system equivalent inertia constant and the power-frequency ratio coefficient unchanged as the energy storage configuration target.

3. The method according to claim 1, characterized in that, The representative power value of the new energy power station is determined based on its historical output power data, including: An empirical cumulative distribution function is constructed based on the historical output power data of the new energy power plant. The corresponding power per-unit value is determined from the empirical cumulative distribution function based on the set confidence level; A representative power value is obtained based on the per-unit power value and the rated capacity of the new energy power station.

4. The method according to claim 2, characterized in that, Based on the energy storage configuration target, the energy storage power capacity required for the energy storage system of the new energy power station to meet inertial support is calculated based on the representative power value. The calculation formula is as follows: ； ； in, H represents the energy storage capacity required by the energy storage system to meet inertial support requirements. ESS The inertia coefficient represents the energy storage. Represents the system's equivalent inertial constant. This represents the representative power value. This represents the system's rated frequency, and K represents the controller coefficient.

5. The method according to claim 2, characterized in that, Based on the energy storage configuration target, the energy storage power capacity required for primary frequency regulation of the new energy power station's energy storage system is calculated using the representative power value, and the calculation formula is as follows: ； ； ； in, This indicates the energy storage capacity required for primary frequency regulation by the energy storage system. Indicates the droop coefficient. Indicates the system's rated frequency. This represents the power-frequency ratio of the system before the generator was replaced. This represents the power-frequency ratio of the system after the generator is replaced. This represents the per-unit value of the droop coefficient. This represents the per-unit value of the frequency deviation. This represents the per-unit value of power change. It represents the change in frequency.

6. A new energy inertial enhancement control system for improving the self-healing capability of power distribution networks, characterized in that, include: The configuration target determination module is used to determine the energy storage configuration target of new energy power plants; The representative power value calculation module is used to determine the representative power value of the new energy power station based on the historical output power data of the new energy power station. The virtual synchronous controller configuration module is used to determine the parameters of the virtual synchronous controller and configure the virtual synchronous controller so that the new energy power plant can simulate the inertial response and primary frequency regulation characteristics of a synchronous generator. The energy storage power capacity calculation module is used to calculate the energy storage power capacity of the new energy power station's energy storage system to meet inertial support and primary frequency regulation, based on the energy storage configuration target, the representative power value, and the virtual synchronous controller parameters, respectively. An energy storage capacity calculation module is used to calculate the energy storage capacity of the new energy power station energy storage system based on the energy storage power capacity; specifically, it includes: Calculate the inertial response energy based on the energy storage power capacity required by the energy storage system to meet inertial support requirements; The calculation formula is as follows: ； in, Let t1 represent the initial moment of the inertial response, t2 represent the moment when the frequency fluctuation reaches its lowest or highest point, and K represent the controller coefficient. Indicates the rate of change of frequency. This indicates the energy storage capacity required by the energy storage system to meet inertial support requirements; Calculate the primary frequency regulation energy based on the energy storage power capacity required by the energy storage system to meet the primary frequency regulation; The calculation formula is as follows: ； in, Indicates the primary frequency modulation energy. This indicates the duration of energy storage participation in a single frequency-modulated discharge. This indicates the duration for which energy storage participates in a single frequency regulation charging cycle. This indicates the energy storage capacity required by the energy storage system to meet primary frequency regulation; The larger value between the inertial response energy and the primary frequency modulation energy is selected as the energy storage capacity of the energy storage system. The verification module is used to configure the energy storage system according to the energy storage capacity, connect the new energy power station with the configured energy storage system to the distribution network, and respond to grid disturbances through the virtual synchronization controller to support the self-healing operation of the distribution network.

7. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed in a computer, causes the computer to perform the method described in any one of claims 1-6.

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