Grid energy storage configuration method and system based on transient stability and sufficient rotational inertia

Abstract

A grid-building energy storage configuration method and system based on transient stability and sufficient rotational inertia, based on the probability density function of net load fluctuation power and the probability density function of interconnection line power, respectively determine the confidence interval of net load fluctuation power and the confidence interval of interconnection line power; the larger value of the absolute value of the boundary of the confidence interval of net load fluctuation power is taken as the extreme unbalanced power caused by net load fluctuation, and the larger value of the absolute value of the boundary of the confidence interval of interconnection line power is taken as the extreme unbalanced power caused by interconnection line fault; the larger value of the extreme unbalanced power caused by net load fluctuation and the extreme unbalanced power caused by interconnection line fault is taken as the extreme unbalanced power of the system; the lower limit values ​​of various configuration parameters of grid-building energy storage are calculated based on the upper limit value of frequency change rate and the upper limit value of maximum frequency deviation by using the extreme unbalanced power of the system, so as to achieve the optimal safety and economy of grid-building energy storage configuration of island power grid.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage configuration, and in particular, relates to a method and system for calculating configuration parameters of energy storage for an island power grid configuration taking into account transient stability and sufficient rotational inertia. Background Art

[0002] The island power grid has problems such as unstable system load, fluctuations in new energy generation, and interconnection line failures, which make it difficult to balance the power supply and demand of the island power grid, thereby affecting the stability of the power system and the reliability of power supply. Island power grids usually rely on unstable renewable energy sources such as wind and solar energy, and the output of these energies is greatly affected by weather and seasonal changes. In addition, the load side of the island power grid also shows obvious seasonality and instability. The failure of the interconnection line will further aggravate the instability of power supply. At this time, the island power grid will enter an isolated network operation state. There is not enough backup power to support the stability of the power grid, and there will be problems such as power outages and load shedding. The grid-type energy storage system is essentially a voltage source. Its inverter will set the voltage reference signal internally, and synchronize with the power grid through the power calculation module and frequency droop control. It has the ability to mobilize its own operation to adjust the output in real time without external power supply, and maintain the voltage output through power output adjustment to form a voltage source grid connection. Therefore, in terms of frequency and inertia support, grid-type energy storage can release the energy stored on the DC side by controlling the energy equivalent to the mechanical energy or damping energy of the synchronous machine inertia, thereby providing inertia response and oscillation suppression, and is more suitable for providing virtual inertia and fast frequency response in a high-proportion new energy power system. The configuration of the grid-type energy storage system is crucial for the island power grid. It can not only help the power grid to smooth the fluctuations of new energy power generation, but also provide inertia support for transient stability at the moment of a fault in the interconnection line. Because the island power grid generally relies mainly on new energy power generation and lacks traditional power sources, its rotational inertia is usually insufficient. At this time, the grid-type energy storage provides inertia support for the island power grid through virtual inertia technology to ensure the transient stability and safety of the power system. At the same time, after safely passing the transient stability period, it can provide power and electricity support during the isolated operation of the island power grid together with the traditional grid-type energy storage until the interconnection line is restored or the problem is solved.

[0003] However, if the configuration of the grid-type energy storage system is too low, it may lead to insufficient inertia support capacity, unable to support the island power grid to cope with extreme situations that threaten transient stability, affecting the safety and reliability of the power grid. At the same time, the construction cost of the grid-type energy storage itself is relatively high, and excessive configuration will increase the system construction cost of the island power grid and cause waste of resources. Therefore, there is currently no optimal configuration method for the grid-type energy storage of the island power grid that can take into account the probabilistic risk of insufficient rotational inertia and cost control for optimal configuration. Summary of the invention

[0004] In order to solve the deficiencies in the prior art, the present invention provides a method and system for calculating the configuration parameters of an island power grid-type energy storage system based on transient stability and sufficient rotational inertia, so as to solve the technical problems that the island power grid-type energy storage system is difficult to achieve optimal safety and economy due to the lack of a method for calculating the configuration parameters of an island power grid-type energy storage system that takes into account both the probabilistic risk of insufficient rotational inertia and cost control.

[0005] The present invention adopts the following technical solution.

[0006] The present invention proposes a grid energy storage configuration method based on transient stability and sufficient rotational inertia, comprising:

[0007] Obtain and utilize the system load and renewable energy power generation in each period to determine the net load in each period, and calculate the net load fluctuation power in each period; obtain the tie line power in each period;

[0008] The Gaussian kernel density estimation method is used to determine the probability density function of the net load fluctuation power and the probability density function of the tie line power; according to the set confidence level, based on the probability density function of the net load fluctuation power and the probability density function of the tie line power, the confidence interval of the net load fluctuation power and the confidence interval of the tie line power are determined respectively;

[0009] The larger value of the absolute value of the boundary of the confidence interval of the net load fluctuation power is taken as the extreme unbalanced power caused by the net load fluctuation, and the larger value of the absolute value of the boundary of the confidence interval of the tie line power is taken as the extreme unbalanced power caused by the tie line fault; the larger value of the extreme unbalanced power caused by the net load fluctuation and the extreme unbalanced power caused by the tie line fault is taken as the extreme unbalanced power of the system;

[0010] The extreme unbalanced power of the system is utilized, and the lower limits of various configuration parameters of the grid-forming energy storage are calculated based on the upper limit of the frequency change rate and the upper limit of the maximum frequency deviation; the grid-forming energy storage is configured based on the lower limits of various configuration parameters of the grid-forming energy storage.

[0011] Preferably, the difference between the system load and the renewable energy power generation in each period is taken as the net load in each period, satisfying the following relationship:

[0012] ,

[0013] In the formula, For the period The net load, For the period The system load, For the period The photovoltaic power generation power, For the period of wind power;

[0014] The net load fluctuation value in each period satisfies the following relationship:

[0015] ,

[0016] In the formula, For the period The net load fluctuation value.

[0017] Preferably, the intermediate value of the probability density function of the net load fluctuation power and the intermediate value of the probability density function of the tie line power are calculated respectively according to the following relationship:

[0018] ,

[0019] In the formula, is the middle value of the probability density function of the net load fluctuation power, is the middle value of the probability density function of the tie line power, is the probability density function of net load fluctuation power, is the probability density function of the tie line power.

[0020] Preferably, according to the set confidence level, the lower and upper boundaries of the confidence interval of the net load fluctuation power are determined by using the middle value of the probability density function of the net load fluctuation power according to the following relationship:

[0021] ,

[0022] In the formula, is the lower boundary of the confidence interval of net load fluctuation, is the upper boundary of the confidence interval of net load fluctuation, is the set confidence level;

[0023] The confidence interval of net load fluctuation is .

[0024] Preferably, according to the set confidence level, the lower and upper boundaries of the confidence interval of the tie line power are determined by using the middle value of the probability density function of the tie line power according to the following relationship:

[0025] ,

[0026] In the formula, is the lower boundary of the confidence interval of the tie line power, is the upper boundary of the confidence interval of the tie line power, is the set confidence level;

[0027] The confidence interval of the tie line power is .

[0028] Preferably, the lower boundary absolute value and the upper boundary absolute value of the confidence interval of the net load fluctuation power are compared, and the larger value of the two absolute values ​​is taken as the extreme unbalanced power generated by the net load fluctuation, satisfying the following relationship:

[0029] ,

[0030] In the formula, Extreme unbalanced power generated by net load fluctuations.

[0031] Preferably, the lower boundary absolute value and the upper boundary absolute value of the confidence interval of the tie line power are compared, and the larger of the two absolute values ​​is taken as the extreme unbalanced power generated by the tie line fault, satisfying the following relationship:

[0032] ,

[0033] In the formula, Extremely unbalanced power generated by a tie line fault.

[0034] Preferably, the greater value of the extreme unbalanced power caused by the net load fluctuation and the extreme unbalanced power caused by the tie line fault is used as the extreme unbalanced power of the system, satisfying the following relationship:

[0035] ,

[0036] In the formula, This is the extremely unbalanced power of the system.

[0037] Preferably, based on the upper limit value of the frequency change rate and the upper limit value of the maximum frequency deviation, the lower limit value of each configuration parameter of the grid-type energy storage is calculated using the following relationship:

[0038] ,

[0039] ,

[0040] ,

[0041] In the formula, To construct grid-type energy storage based on the power demand of frequency change rate, To construct grid-type energy storage based on the power demand of maximum frequency deviation, is the amount of electricity used for grid-type energy storage, is the power of grid-type energy storage, is the extremely unbalanced power of the system, is the upper limit of the frequency change rate, is the upper limit of the maximum frequency deviation, is the rated frequency, is the response time of primary frequency modulation of grid-type energy storage, is the speed inequality rate of the grid-type energy storage, is the minimum charging and discharging time of grid-type energy storage, is the engineering margin factor.

[0042] The present invention also proposes a grid-building energy storage configuration system based on transient stability and sufficient rotational inertia, comprising:

[0043] The acquisition module is used to obtain and utilize the system load and renewable energy power generation in each period to determine the net load in each period, and calculate the net load fluctuation power in each period; obtain the tie line power in each period;

[0044] The extreme unbalanced power calculation module is used to determine the probability density function of the net load fluctuation power and the probability density function of the tie line power by using the Gaussian kernel density estimation method; according to the set confidence level, based on the probability density function of the net load fluctuation power and the probability density function of the tie line power, respectively determine the confidence interval of the net load fluctuation power and the confidence interval of the tie line power; take the larger value of the absolute value of the boundary of the confidence interval of the net load fluctuation power as the extreme unbalanced power caused by the net load fluctuation, and take the larger value of the absolute value of the boundary of the confidence interval of the tie line power as the extreme unbalanced power caused by the tie line fault; take the larger value of the extreme unbalanced power caused by the net load fluctuation and the extreme unbalanced power caused by the tie line fault as the extreme unbalanced power of the system;

[0045] The grid-forming energy storage configuration module is used to utilize the extremely unbalanced power of the system, calculate the lower limit values ​​of various configuration parameters of the grid-forming energy storage based on the upper limit value of the frequency change rate and the upper limit value of the maximum frequency deviation; and configure the grid-forming energy storage based on the lower limit values ​​of various configuration parameters of the grid-forming energy storage.

[0046] The present invention is also a terminal, comprising a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method.

[0047] The present invention is also a computer-readable storage medium having a computer program stored thereon, which implements the steps of the method when executed by a processor.

[0048] The beneficial effect of the present invention is that, compared with the prior art, it at least includes providing a scientific basis for the configuration of a grid-type energy storage system by analyzing historical data, calculating net load fluctuations, performing probability density fitting, and calculating confidence intervals. This method can make a quantitative trade-off between the probability risk of insufficient moment of inertia and economic benefits, while ensuring the stability of the power grid, reducing unnecessary grid-type energy storage configuration, thereby maximizing cost-effectiveness. Compared with traditional methods, such as directly configuring traditional grid-type energy storage according to the medium- and long-term system load forecast of the island power grid and the scale of new energy installed capacity, the method proposed in the present invention is more direct and accurate, more targeted to the characteristics of the island power grid and its demand for grid-type energy storage, and can make a quantitative trade-off between the probability risk of insufficient moment of inertia and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a flow chart of a network energy storage configuration method based on transient stability and sufficient moment of inertia proposed by the present invention;

[0050] Figure 2 is the probability density function of the net load fluctuation power in the embodiment of the present invention and its fitting effect;

[0051] Figure 3 It is the probability density function of the tie line power and its fitting effect in the embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0053] The present invention proposes a grid-connected energy storage configuration method based on transient stability and sufficient rotational inertia to calculate the grid-connected energy storage configuration parameters of the island power grid, such as Figure 1 As shown, including:

[0054] Step 1: Obtain and use the system load and renewable energy generation power in each time period to determine the net load in each time period; obtain the interconnection line power in each time period.

[0055] In the embodiment, historical data such as system load, photovoltaic power generation power, wind power, and interconnection line power are obtained; historical data within a period of time is counted, including system load, photovoltaic power generation power, wind power, and interconnection line power in each time period (the time period length can be 5 minutes or 15 minutes, and 5 minutes is taken as an example here).

[0056] Specifically, the difference between the system load and the new energy power generation power in each period is the net load in each period; in the embodiment, the net load in each period satisfies the following relationship:

[0057] ,

[0058] In the formula, For the period The net load, For the period The system load, For the period The photovoltaic power generation power, For the period of wind power.

[0059] Step 2: Calculate the net load fluctuation value in each time period.

[0060] The net load fluctuation value in each period satisfies the following relationship:

[0061] ,

[0062] In the formula, For the period The net load fluctuation value.

[0063] Step 3: Using Gaussian kernel density estimation method, the net load fluctuation power in each time period is used to determine the probability density function of the net load fluctuation power, and the interconnection line power in each time period is used to determine the probability density function of the interconnection line power.

[0064] Specifically, the Gaussian kernel density estimation method is used to perform probability density fitting on the net load fluctuation power data (negative values ​​represent a decrease in net load, and positive values ​​represent an increase in net load) and the tie line power data (negative values ​​represent the tie line outgoing power, and positive values ​​represent the tie line incoming power), and the probability density function of the net load fluctuation power is obtained. and the probability density function of the tie line power .

[0065] The probability density histogram method is used to count the frequency, probability and probability density of the net load fluctuation power data and the tie line power data in different intervals, which is used to compare and verify the fitting effect of the Gaussian kernel density estimation method. The probability density function of the net load fluctuation power and its fitting effect are detailed in Figure 2 The probability density function of the tie line power and its fitting effect are detailed in Figure 3 ,The curve graph of the Gaussian kernel density estimation method and the bar graph of the histogram method have a good ,fit, indicating that the fitting effect is good.

[0066] exist Figure 2 and Figure 3In the figure, whether it is the curve of the Gaussian kernel density estimation method or the bar graph of the histogram method, the horizontal axis is the size interval of the net load fluctuation power or the tie line power, and the vertical axis is the corresponding probability density. At the same time, whether it is the curve of the Gaussian kernel density estimation method or the bar graph of the histogram method, the area enclosed by it and the horizontal axis is the probability sum, which is 1.

[0067] Step 4, according to the set confidence level, based on the probability density function of the net load fluctuation power and the probability density function of the tie line power, respectively determine the confidence interval of the net load fluctuation power and the confidence interval of the tie line power; take the larger value of the absolute value of the boundary of the confidence interval of the net load fluctuation power as the extreme unbalanced power caused by the net load fluctuation, and take the larger value of the absolute value of the boundary of the confidence interval of the tie line power as the extreme unbalanced power caused by the tie line fault; take the larger value of the extreme unbalanced power caused by the net load fluctuation and the extreme unbalanced power caused by the tie line fault as the extreme unbalanced power of the system.

[0068] Specifically, step 4 includes:

[0069] Step 4.1, calculate the middle value of the probability density function of the net load fluctuation power and the middle value of the probability density function of the tie line power using the following relationship:

[0070] ,

[0071] In the formula, is the middle value of the probability density function of the net load fluctuation power, is the middle value of the probability density function of the tie line power, is the probability density function of net load fluctuation power, is the probability density function of the tie line power;

[0072] Step 4.2, according to the set confidence level , using the middle value of the probability density function of the net load fluctuation power, the lower and upper boundaries of the confidence interval of the net load fluctuation power are determined by the following relationship:

[0073] ,

[0074] In the formula, is the lower boundary of the confidence interval of net load fluctuation, is the upper boundary of the confidence interval of net load fluctuation, is the set confidence level;

[0075] The confidence interval of net load fluctuation is ;

[0076] In the embodiment, when the confidence level is 98%, the lower limit and upper limit of the confidence interval of the net load fluctuation power satisfy the following relationship:

[0077] ,

[0078] Step 4.3, according to the set confidence level , using the middle value of the probability density function of the tie line power, the lower and upper boundaries of the confidence interval of the tie line power are determined by the following relationship:

[0079] ,

[0080] In the formula, is the lower boundary of the confidence interval of the tie line power, is the upper boundary of the confidence interval of the tie line power, is the set confidence level.

[0081] Then the confidence interval of the tie line power is ;

[0082] In the embodiment, when the confidence level is 98%, the lower limit and upper limit of the confidence interval of the tie line power satisfy the following relationship:

[0083] ,

[0084] Step 4.4, comparing the lower boundary absolute value and the upper boundary absolute value of the confidence interval of the net load fluctuation power, and taking the larger value of the two absolute values ​​as the extreme unbalanced power generated by the net load fluctuation;

[0085] In the embodiment, It indicates the excess active power caused by the sudden increase of renewable energy power generation and the significant reduction of system load, and the corresponding increase of system frequency. It indicates that the active power is insufficient due to the sudden decrease of renewable energy power generation and the increase of system load, and the corresponding system frequency is reduced. In the case of net load fluctuation, the increase of net load in the current period relative to the previous period may cause an active power gap in the current period, and the decrease of net load in the current period relative to the previous period may cause an active power surplus in the current period. Both surplus and deficit belong to unbalanced power and will cause frequency changes.

[0086] Therefore, the net load fluctuation power corresponding to the 98% confidence level is used to characterize the unbalanced power that may occur in the case of extreme net load fluctuation, and the larger absolute value of the lower limit value (generally negative value, excess active power) and the upper limit value (generally positive value, gap active power) of the net load fluctuation power at the 98% confidence level is taken as the extreme unbalanced power. |,| |) is the extremely unbalanced power generated by system load and new energy fluctuations (net load fluctuations), satisfying the following relationship:

[0087] ,

[0088] In the formula, Extreme unbalanced power generated by net load fluctuations.

[0089] Step 4.5, comparing the lower boundary absolute value and the upper boundary absolute value of the confidence interval of the tie line power, and taking the larger value of the two absolute values ​​as the extreme unbalanced power generated by the tie line fault;

[0090] In the embodiment, It indicates that the sudden failure of the interconnection line results in the inability to export power from the island and excess active power, which corresponds to an increase in the system frequency; Characterizes the situation where a sudden failure of the interconnection line results in the inability to deliver electricity from outside the island and insufficient active power, which corresponds to a decrease in system frequency. In the case of an interconnection line failure, the original interconnection line has excess active power that cannot be delivered or a gap in active power that cannot be delivered. Whether it is excess or gap, it is unbalanced power and will cause frequency changes. Therefore, the interconnection line power corresponding to the 98% confidence level is used to characterize the unbalanced power that may occur in the event of a interconnection line failure, and the larger absolute value of the lower limit value of the interconnection line power at the 98% confidence level (generally a negative value, excess active power) and the upper limit value (generally a positive value, gap active power) is taken as the extreme unbalanced power. Therefore, max (| |,| |) is the extreme unbalanced power generated by the tie line fault, satisfying the following relationship:

[0091] ,

[0092] In the formula, Extremely unbalanced power generated by a tie line fault.

[0093] Step 4.6, the larger value of the extreme unbalanced power caused by the net load fluctuation and the extreme unbalanced power caused by the tie line fault is taken as the extreme unbalanced power of the system, satisfying the following relationship:

[0094] ,

[0095] In the formula, This is the extremely unbalanced power of the system.

[0096] Step 5, using the extremely unbalanced power of the system, based on the upper limit value of the frequency change rate and the upper limit value of the maximum frequency deviation, calculate the lower limit value of each configuration parameter of the grid-forming energy storage; and configure the grid-forming energy storage based on the lower limit value of each configuration parameter of the grid-forming energy storage.

[0097] At the moment of extreme unbalanced power in the system, the transient stability indicators of the power system include the frequency change rate and maximum frequency deviation , if the inertia support of the grid-type energy storage is sufficient, the frequency change rate and maximum frequency deviation Therefore, according to the following relationship, when the frequency change rate and the maximum frequency deviation do not exceed the corresponding upper limit value, the lower limit value of each configuration parameter of the grid-type energy storage that meets the safety conditions is calculated:

[0098] ,

[0099] ,

[0100] ,

[0101] In the formula, To construct grid-type energy storage based on the power demand of frequency change rate, To construct grid-type energy storage based on the power demand of maximum frequency deviation, is the amount of electricity used for grid-type energy storage, is the power of grid-type energy storage, For extremely unbalanced power, The upper limit of the frequency change rate, refer to "Power Quality Power System Frequency Deviation (GB / T 15945-2008)" Take ±1.67Hz / s, The upper limit of the maximum frequency deviation is as follows: Technical Requirements for Inertia Support and Primary Frequency Regulation Capability of Power Systems (DL / T2669-2023) Take ±0.5Hz, is the rated frequency, which is generally 50Hz in China. For the response time of primary frequency modulation of energy storage, refer to "General Technical Requirements for Electrochemical Energy Storage Systems in Power Systems (GB / T 36558-2023)" Take 0.5s, The speed inequality of the grid-type energy storage is equal to the inverse of its active frequency modulation coefficient. According to the Technical Specifications for Grid-Connected Grid-Type Energy Storage Systems (T / CES 243-2023), the active frequency modulation coefficient is generally 20~50, that is, the speed inequality is generally 2%~5%. The minimum charging and discharging time of energy storage is 2 to 4 hours, considering the minimum charging and discharging time of mainstream energy storage in the market and the operation time of the island power grid. It is the engineering margin factor, which is determined based on actual usage requirements, for example 10%.

[0102] The lower limit of the configuration parameters is calculated based on the upper limit of the frequency change rate and the upper limit of the maximum frequency deviation. This not only meets the requirements of transient stability of the power system, but also reflects the index of sufficient moment of inertia. Only when the moment of inertia is sufficient will a certain unbalanced power disturbance not cause the frequency change rate and the maximum frequency deviation to exceed the limit requirements. Therefore, the energy storage configuration parameters calculated in reverse according to the upper limit requirements of the frequency change rate and the maximum frequency deviation can achieve sufficient moment of inertia.

[0103] Based on the lower limits of various configuration parameters of the grid-type energy storage, the rated power and rated capacity of the grid-type energy storage are configured.

[0104] The present invention also proposes a grid-building energy storage configuration system based on transient stability and sufficient rotational inertia, comprising:

[0105] The acquisition module is used to obtain and utilize the system load and renewable energy power generation in each period to determine the net load in each period, and calculate the net load fluctuation power in each period; obtain the tie line power in each period;

[0106] The extreme unbalanced power calculation module is used to determine the probability density function of the net load fluctuation power and the probability density function of the tie line power by using the Gaussian kernel density estimation method; according to the set confidence level, based on the probability density function of the net load fluctuation power and the probability density function of the tie line power, respectively determine the confidence interval of the net load fluctuation power and the confidence interval of the tie line power; take the larger value of the absolute value of the boundary of the confidence interval of the net load fluctuation power as the extreme unbalanced power caused by the net load fluctuation, and take the larger value of the absolute value of the boundary of the confidence interval of the tie line power as the extreme unbalanced power caused by the tie line fault; take the larger value of the extreme unbalanced power caused by the net load fluctuation and the extreme unbalanced power caused by the tie line fault as the extreme unbalanced power of the system;

[0107] The grid-type energy storage configuration module is used to utilize the extremely unbalanced power of the system and calculate the lower limit values ​​of each configuration parameter of the grid-type energy storage based on the upper limit value of the transient stability index of the power system; and configure the grid-type energy storage based on the lower limit values ​​of each configuration parameter of the grid-type energy storage.

[0108] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0109] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the above. More specific examples (a non-exhaustive list) of computer-readable storage media include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the above. The computer-readable storage medium used herein is not to be interpreted as a transient signal itself, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0110] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0111] The computer program instructions for performing the operations of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer, partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect through the Internet). In some embodiments, by using the state information of the computer-readable program instructions to personalize an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), the electronic circuit may execute the computer-readable program instructions, thereby implementing various aspects of the present disclosure.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for configuring grid energy storage based on transient stability and sufficient moment of inertia, characterized in that: include: Obtain and utilize the system load and renewable energy power generation in each period to determine the net load in each period, and calculate the net load fluctuation power in each period; obtain the tie line power in each period; The Gaussian kernel density estimation method is used to determine the probability density function of the net load fluctuation power and the probability density function of the tie line power; according to the set confidence level, based on the probability density function of the net load fluctuation power and the probability density function of the tie line power, the confidence interval of the net load fluctuation power and the confidence interval of the tie line power are determined respectively; The larger value of the absolute value of the boundary of the confidence interval of the net load fluctuation power is taken as the extreme unbalanced power caused by the net load fluctuation, and the larger value of the absolute value of the boundary of the confidence interval of the tie line power is taken as the extreme unbalanced power caused by the tie line fault; the larger value of the extreme unbalanced power caused by the net load fluctuation and the extreme unbalanced power caused by the tie line fault is taken as the extreme unbalanced power of the system; Using the extremely unbalanced power of the system, based on the upper limit of the frequency change rate and the upper limit of the maximum frequency deviation, the lower limit values ​​of the configuration parameters of the grid-forming energy storage are calculated, including: the power demand of the grid-forming energy storage based on the frequency change rate, and the power demand of the grid-forming energy storage based on the maximum frequency deviation; The grid-type energy storage is configured based on the lower limit values ​​of each configuration parameter of the grid-type energy storage, including extracting the maximum value from the power demand of the grid-type energy storage based on the frequency change rate, the power demand of the grid-type energy storage based on the maximum frequency deviation, and the product of the system's extreme unbalanced power and the minimum charging and discharging time of the grid-type energy storage, and correcting the maximum value using the engineering margin coefficient to obtain the power of the grid-type energy storage.

2. The method for configuring grid energy storage based on transient stability and sufficient moment of inertia according to claim 1 is characterized in that: The difference between the system load and the renewable energy power generation in each period is taken as the net load in each period, satisfying the following relationship: In the formula, For the period The net load, For the period The system load, For the period The photovoltaic power generation power, For the period of wind power; The net load fluctuation value in each period satisfies the following relationship: In the formula, For the period The net load fluctuation value.

3. The method for configuring grid energy storage based on transient stability and sufficient moment of inertia according to claim 1 is characterized in that: The middle value of the probability density function of the net load fluctuation power and the middle value of the probability density function of the tie line power are calculated using the following relationship: In the formula, is the middle value of the probability density function of the net load fluctuation power, is the middle value of the probability density function of the tie line power, is the probability density function of net load fluctuation power, is the probability density function of the tie line power.

4. The method for configuring grid energy storage based on transient stability and sufficient moment of inertia according to claim 3 is characterized in that: According to the set confidence level, the lower and upper boundaries of the confidence interval of the net load fluctuation power are determined by using the middle value of the probability density function of the net load fluctuation power according to the following relationship: In the formula, is the lower boundary of the confidence interval of net load fluctuation, is the upper boundary of the confidence interval of net load fluctuation, is the set confidence level; The confidence interval of net load fluctuation is .

5. The method for configuring grid energy storage based on transient stability and sufficient moment of inertia according to claim 4 is characterized in that: According to the set confidence level, the lower and upper boundaries of the confidence interval of the tie line power are determined by using the middle value of the probability density function of the tie line power according to the following relationship: In the formula, is the lower boundary of the confidence interval of the tie line power, is the upper boundary of the confidence interval of the tie line power, is the set confidence level; The confidence interval of the tie line power is .

6. The method for configuring grid energy storage based on transient stability and sufficient moment of inertia according to claim 5 is characterized in that: Compare the lower and upper bound absolute values ​​of the confidence interval of the net load fluctuation power, and take the larger of the two absolute values ​​as the extreme unbalanced power generated by the net load fluctuation, satisfying the following relationship: In the formula, Extreme unbalanced power generated by net load fluctuations.

7. The method for configuring grid energy storage based on transient stability and sufficient moment of inertia according to claim 6 is characterized in that: Compare the lower and upper absolute values ​​of the confidence interval of the tie line power, and take the larger of the two absolute values ​​as the extreme unbalanced power generated by the tie line fault, satisfying the following relationship: In the formula, Extremely unbalanced power generated by a tie line fault.

8. The method for configuring grid energy storage based on transient stability and sufficient moment of inertia according to claim 7 is characterized in that: The larger value of the extreme unbalanced power caused by the net load fluctuation and the extreme unbalanced power caused by the tie line fault is taken as the extreme unbalanced power of the system, satisfying the following relationship: In the formula, This is the extremely unbalanced power of the system.

9. The method for configuring grid energy storage based on transient stability and sufficient moment of inertia according to claim 1 is characterized in that: Based on the upper limit of the frequency change rate and the upper limit of the maximum frequency deviation, the lower limit of each configuration parameter of the grid-type energy storage is calculated using the following relationship: In the formula, To construct grid-type energy storage based on the power demand of frequency change rate, To construct grid-type energy storage based on the power demand of maximum frequency deviation, is the amount of electricity used for grid-type energy storage, is the power of grid-type energy storage, is the extremely unbalanced power of the system, is the upper limit of the frequency change rate, is the upper limit of the maximum frequency deviation, is the rated frequency, is the response time of primary frequency modulation of grid-type energy storage, is the speed inequality rate of the grid-type energy storage, is the minimum charging and discharging time of grid-type energy storage, is the engineering margin factor.

10. A grid-connected energy storage configuration system based on transient stability and sufficient rotational inertia, characterized in that: include: The acquisition module is used to obtain and utilize the system load and renewable energy power generation in each period to determine the net load in each period, and calculate the net load fluctuation power in each period; obtain the tie line power in each period; The extreme unbalanced power calculation module is used to determine the probability density function of the net load fluctuation power and the probability density function of the tie line power by using the Gaussian kernel density estimation method; according to the set confidence level, based on the probability density function of the net load fluctuation power and the probability density function of the tie line power, respectively determine the confidence interval of the net load fluctuation power and the confidence interval of the tie line power; take the larger value of the absolute value of the boundary of the confidence interval of the net load fluctuation power as the extreme unbalanced power caused by the net load fluctuation, and take the larger value of the absolute value of the boundary of the confidence interval of the tie line power as the extreme unbalanced power caused by the tie line fault; take the larger value of the extreme unbalanced power caused by the net load fluctuation and the extreme unbalanced power caused by the tie line fault as the extreme unbalanced power of the system; The grid-forming energy storage configuration module is used to utilize the extremely unbalanced power of the system. Based on the upper limit of the frequency change rate and the upper limit of the maximum frequency deviation, the lower limit of each configuration parameter of the grid-forming energy storage is calculated, including: the power demand of the grid-forming energy storage based on the frequency change rate, and the power demand of the grid-forming energy storage based on the maximum frequency deviation; The grid-type energy storage is configured based on the lower limit values ​​of each configuration parameter of the grid-type energy storage, including extracting the maximum value from the power demand of the grid-type energy storage based on the frequency change rate, the power demand of the grid-type energy storage based on the maximum frequency deviation, and the product of the system's extreme unbalanced power and the minimum charging and discharging time of the grid-type energy storage, and correcting the maximum value using the engineering margin coefficient to obtain the power of the grid-type energy storage.

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