Security and stability analysis method and system considering networking type energy storage

Abstract

The invention discloses a security and stability analysis method and system considering networking type energy storage, and belongs to the technical field of transient stability analysis of a power system. The method comprises the following steps: constructing a data analysis model of network construction type energy storage for a network construction type energy storage access power grid; on the basis of the mathematical analysis model, constructing a power grid simulation digital model containing network construction type energy storage; based on the power grid simulation digital model, determining different operation states of the network construction type energy storage, and generating power grid operation mode data of various scenes under the different operation states; and according to the power grid operation mode data, establishing a power grid safety and stability analysis index, and according to the power grid safety and stability analysis index, carrying out safety and stability analysis on the power grid of the network construction type energy storage access. According to the method, multiple security constraints of the power grid can be taken into consideration, novel power grid equipment such as network construction type energy storage equipment is taken into consideration, system frequency response and transient voltage fluctuation analysis index change analysis are taken into consideration, and security and stability analysis of the power grid is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of transient stability analysis of power systems, and more specifically, to a safety and stability analysis method and system considering grid-connected energy storage. Background Art

[0002] In the new power system where new energy occupies an important position, as the proportion of power electronic converters continues to rise, the grid structure dominated by synchronous generators is quietly changing. This change has led to a significant increase in the proportion of converters in the power system, which in turn has greatly reduced the inertia of the system, and the system frequency indicators have also shown a deteriorating trend. However, it is worth noting that compared with synchronous generators, converters have a faster response speed and stronger power control capabilities. In order to enhance the stability of the "double high" system, grid-type energy storage technology came into being. It makes full use of the flexible and controllable characteristics of the converter, effectively compensates for the inherent inertial damping characteristics that are missing in the system, and provides solid voltage and frequency support for the entire system.

[0003] As an innovative means to improve the safety and stability of new power systems, the impact of grid-connected energy storage on the system needs to be analyzed in detail. Summary of the invention

[0004] In view of the above problems, the present invention proposes a safety and stability analysis method considering grid-type energy storage, including:

[0005] Construct a data analysis model for grid-based energy storage for the grid to which grid-based energy storage is connected;

[0006] Based on the mathematical analysis model, a power grid simulation digital model including grid-building energy storage is constructed;

[0007] Based on the power grid simulation digital model, different operating states of the grid-connected energy storage are determined, and power grid operation mode data of multiple scenarios under the different operating states are generated;

[0008] Based on the grid operation mode data, grid safety and stability analysis indicators are established, and based on the grid safety and stability analysis indicators, a safety and stability analysis is performed on the grid to which the grid-connected energy storage is connected.

[0009] Optional data analysis models for grid-connected energy storage, including:

[0010] The relationship model between power, frequency and voltage of grid-type energy storage is as follows:

[0011]

[0012] in, is the grid voltage, is the grid-connected voltage of the grid-type energy storage, Q ES is the reactive power of the grid-type energy storage, X is the reactance, δ is the power angle, P ES It is the active power of grid-type energy storage.

[0013] Optional digital model of grid simulation including grid-connected energy storage, including:

[0014] Power grid static simulation model and power grid transient simulation model;

[0015] The power grid static simulation model comprises:

[0016] Line parameters, including: per-unit resistance value, per-unit reactance value, earth susceptance, rated current and loop mark of parallel lines;

[0017] Transformer parameters, including leakage reactance, rated capacity, parallel circuit loop and fixed tap;

[0018] Load model, including: constant active load model and constant reactive load model;

[0019] Thermal power units, including: actual active output and maximum active output;

[0020] New energy units, including: actual active output and maximum active output;

[0021] Grid-following / grid-building energy storage, including: actual active output and maximum active output;

[0022] The power grid transient simulation model comprises:

[0023] Line parameters, including: zero-sequence resistance per unit value and zero-sequence reactance per unit value;

[0024] Transformer parameters, including: zero-sequence reactance per unit value;

[0025] Transient control model of thermal power unit;

[0026] Transient control model of new energy units;

[0027] Grid-following / grid-building energy storage transient control model.

[0028] Optional, different operating states, including:

[0029] Charging state, discharging state and standby state.

[0030] Optionally, after determining different operating states of the grid-type energy storage, a grid-type energy storage charging and discharging mathematical model is constructed, and based on the grid-type energy storage charging and discharging mathematical model, grid operation mode data for multiple scenarios under different operating states are generated.

[0031] Optionally, the model formula of the grid-type energy storage charging and discharging mathematical model is as follows:

[0032]

[0033] Among them, ES SOC(t) is the state of charge of the energy storage at time t, R t is the current capacity, R ES is the system capacity, ES SOC(t-1) is the state of charge of the grid-type energy storage at time t-1, P ch is the charging power, η ch is the charging efficiency, △t is a sampling period, P dis is the discharge power, η dis is the discharge efficiency.

[0034] Optional, grid security and stability analysis indicators, including:

[0035] System frequency evaluation indicators and transient voltage fluctuation evaluation indicators.

[0036] Optional, the expression of the system frequency evaluation index is as follows:

[0037] Δf1=f0-f1

[0038] Among them, Δf1 is the maximum frequency offset, f0 is the system frequency corresponding to the lowest frequency point, and f1 is the system reference frequency.

[0039] Optionally, the expression of transient voltage fluctuation evaluation index is as follows:

[0040]

[0041] Among them, ΔU1 is the system voltage deviation level, Z is the number of nodes, and U q is the qth node voltage, U N is the node rated voltage.

[0042] Optionally, the method further includes:

[0043] According to the grid operation mode data, a short-circuit current check is performed on the grid to which the grid-connected energy storage is connected.

[0044] On the other hand, the present invention also proposes a safety and stability analysis system considering grid-type energy storage, comprising:

[0045] A first modeling unit is used to construct a data analysis model of the grid-building energy storage for the grid to which the grid-building energy storage is connected;

[0046] A second modeling unit is used to construct a power grid simulation digital model including grid-building energy storage based on the mathematical analysis model;

[0047] A data generation unit, used to determine different operating states of the grid-building energy storage based on the grid simulation digital model, and generate grid operation mode data of multiple scenarios under the different operating states;

[0048] The analysis unit is used to establish a power grid safety and stability analysis index based on the power grid operation mode data, and to perform a safety and stability analysis on the power grid to which the grid-type energy storage is connected based on the power grid safety and stability analysis index.

[0049] Optional data analysis models for grid-connected energy storage, including:

[0050] The relationship model between power, frequency and voltage of grid-type energy storage is as follows:

[0051]

[0052] in, is the grid voltage, is the grid-connected voltage of the grid-type energy storage, Q ES is the reactive power of the grid-type energy storage, X is the reactance, δ is the power angle, P ES It is the active power of grid-type energy storage.

[0053] Optional digital model of grid simulation including grid-connected energy storage, including:

[0054] Power grid static simulation model and power grid transient simulation model;

[0055] The power grid static simulation model comprises:

[0056] Line parameters, including: per-unit resistance value, per-unit reactance value, earth susceptance, rated current and loop mark of parallel lines;

[0057] Transformer parameters, including leakage reactance, rated capacity, parallel circuit loop and fixed tap;

[0058] Load model, including: constant active load model and constant reactive load model;

[0059] Thermal power units, including: actual active output and maximum active output;

[0060] New energy units, including: actual active output and maximum active output;

[0061] Grid-following / grid-building energy storage, including: actual active output and maximum active output;

[0062] The power grid transient simulation model comprises:

[0063] Line parameters, including: zero-sequence resistance per unit value and zero-sequence reactance per unit value;

[0064] Transformer parameters, including: zero-sequence reactance per unit value;

[0065] Transient control model of thermal power unit;

[0066] Transient control model of new energy units;

[0067] Grid-following / grid-building energy storage transient control model.

[0068] Optional, different operating states, including:

[0069] Charging state, discharging state and standby state.

[0070] Optionally, after determining different operating states of the grid-type energy storage, a grid-type energy storage charging and discharging mathematical model is constructed, and based on the grid-type energy storage charging and discharging mathematical model, grid operation mode data for multiple scenarios under different operating states are generated.

[0071] Optionally, the model formula of the grid-type energy storage charging and discharging mathematical model is as follows:

[0072]

[0073] Among them, ES SOC(t) is the state of charge of the energy storage at time t, R t is the current capacity, R ES is the system capacity, ES SOC(t-1) is the state of charge of the grid-type energy storage at time t-1, P ch is the charging power, η ch is the charging efficiency, △t is a sampling period, P dis is the discharge power, η dis is the discharge efficiency.

[0074] Optional, grid security and stability analysis indicators, including:

[0075] System frequency evaluation indicators and transient voltage fluctuation evaluation indicators.

[0076] Optional, the expression of the system frequency evaluation index is as follows:

[0077] Δf1=f0-f1

[0078] Among them, Δf1 is the maximum frequency offset, f0 is the system frequency corresponding to the lowest frequency point, and f1 is the system reference frequency.

[0079] Optionally, the expression of transient voltage fluctuation evaluation index is as follows:

[0080]

[0081] Among them, ΔU1 is the system voltage deviation level, Z is the number of nodes, and U q is the qth node voltage, U N is the node rated voltage.

[0082] Optionally, the analysis unit is further configured to:

[0083] According to the grid operation mode data, a short-circuit current check is performed on the grid to which the grid-connected energy storage is connected.

[0084] In yet another aspect, the present invention further provides a computing device, comprising: one or more processors;

[0085] a processor for executing one or more programs;

[0086] When the one or more programs are executed by the one or more processors, the above-described method is implemented.

[0087] In yet another aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed, the method described above is implemented.

[0088] Compared with the prior art, the present invention has the following beneficial effects:

[0089] The present invention provides a safety and stability analysis method considering grid-type energy storage, including: constructing a data analysis model of grid-type energy storage for the grid to which the grid-type energy storage is connected; constructing a grid simulation digital model including the grid-type energy storage based on the mathematical analysis model; determining different operating states of the grid-type energy storage based on the grid simulation digital model, and generating grid operation mode data for multiple scenarios under the different operating states; establishing grid safety and stability analysis indicators based on the grid operation mode data, and performing safety and stability analysis on the grid to which the grid-type energy storage is connected based on the grid safety and stability analysis indicators. The present invention can take into account multiple safety constraints of the grid, take into account new grid equipment such as grid-type energy storage, take into account the change analysis of system frequency response and transient voltage fluctuation analysis indicators, and achieve the comprehensiveness and safety of grid safety and stability analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] Figure 1 is a flow chart of the method of the present invention;

[0091] Figure 2 It is a structural diagram of the system of the present invention. DETAILED DESCRIPTION

[0092] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0093] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0094] Embodiment 1:

[0095] The present invention proposes a safety and stability analysis method considering grid-type energy storage, such as Figure 1 As shown, including:

[0096] Step 1: Construct a data analysis model for the grid-building energy storage for the grid-building energy storage to which the grid-building energy storage is connected;

[0097] Step 2: Based on the mathematical analysis model, a power grid simulation digital model including grid-building energy storage is constructed;

[0098] Step 3: Based on the grid simulation digital model, determine different operating states of the grid-connected energy storage, and generate grid operation mode data for multiple scenarios under the different operating states;

[0099] Step 4: Establish grid security and stability analysis indicators based on the grid operation mode data, and conduct security and stability analysis on the grid to which the grid-connected energy storage is connected based on the grid security and stability analysis indicators.

[0100] Among them, the data analysis model of grid-type energy storage includes:

[0101] The relationship model between power, frequency and voltage of grid-type energy storage is as follows:

[0102]

[0103] in, is the grid voltage, is the grid-connected voltage of the grid-type energy storage, Q ES is the reactive power of the grid-type energy storage, X is the reactance, δ is the power angle, P ES It is the active power of grid-type energy storage.

[0104] Among them, the grid simulation digital model of grid-type energy storage includes:

[0105] Power grid static simulation model and power grid transient simulation model;

[0106] The power grid static simulation model comprises:

[0107] Line parameters, including: per-unit resistance value, per-unit reactance value, earth susceptance, rated current and loop mark of parallel lines;

[0108] Transformer parameters, including leakage reactance, rated capacity, parallel circuit loop and fixed tap;

[0109] Load model, including: constant active load model and constant reactive load model;

[0110] Thermal power units, including: actual active output and maximum active output;

[0111] New energy units, including: actual active output and maximum active output;

[0112] Grid-following / grid-building energy storage, including: actual active output and maximum active output;

[0113] The power grid transient simulation model comprises:

[0114] Line parameters, including: zero-sequence resistance per unit value and zero-sequence reactance per unit value;

[0115] Transformer parameters, including: zero-sequence reactance per unit value;

[0116] Transient control model of thermal power unit;

[0117] Transient control model of new energy units;

[0118] Grid-following / grid-building energy storage transient control model.

[0119] Among them, different operating states include:

[0120] Charging state, discharging state and standby state.

[0121] Among them, after determining the different operating states of the grid-type energy storage, a grid-type energy storage charging and discharging mathematical model is constructed, and based on the grid-type energy storage charging and discharging mathematical model, power grid operation mode data of various scenarios under different operating states are generated.

[0122] Among them, the model formula of the grid-type energy storage charging and discharging mathematical model is as follows:

[0123]

[0124] Among them, ES SOC(t)is the state of charge of the energy storage at time t, R t is the current capacity, R ES is the system capacity, ES SOC(t-1) is the state of charge of the grid-type energy storage at time t-1, P ch is the charging power, η ch is the charging efficiency, △t is a sampling period, P dis is the discharge power, η dis is the discharge efficiency.

[0125] Among them, the power grid security and stability analysis indicators include:

[0126] System frequency evaluation indicators and transient voltage fluctuation evaluation indicators.

[0127] Among them, the expression of the system frequency evaluation index is as follows:

[0128] Δf1=f0-f1

[0129] Among them, Δf1 is the maximum frequency offset, f0 is the system frequency corresponding to the lowest frequency point, and f1 is the system reference frequency.

[0130] Among them, the expression of transient voltage fluctuation evaluation index is as follows:

[0131]

[0132] Among them, ΔU1 is the system voltage deviation level, Z is the number of nodes, and U q is the qth node voltage, U N is the node rated voltage.

[0133] The method further includes:

[0134] According to the grid operation mode data, a short-circuit current check is performed on the grid to which the grid-connected energy storage is connected.

[0135] The present invention is further described below with reference to specific cases:

[0136] Implementation steps include:

[0137] Step 1: Construct a mathematical analysis model for grid-type energy storage;

[0138] Step 2: Construct a digital model of power grid simulation including grid-connected energy storage;

[0139] Step 3: Based on the different operating states of the grid-connected energy storage, generate grid operation mode data under various scenarios;

[0140] Step 4: Based on data from different operating modes, grid safety and stability analysis indicators are proposed, and grid safety and stability analysis and short-circuit current verification are carried out for grid-connected energy storage scenarios.

[0141] In step 1, a mathematical analysis model of grid-type energy storage is constructed.

[0142] The core of the frequency and voltage control mechanism of synchronous generators is to use precise control of active power and reactive power to achieve a dynamic balance between system frequency and voltage. This characteristic is called active frequency characteristic and reactive voltage characteristic. Below, we will analyze in depth the relationship between power, frequency and voltage of grid-type energy storage.

[0143] The apparent power of grid-type energy storage can be expressed as follows:

[0144]

[0145]

[0146] In the above formula, S ES Represents the apparent power of the grid-type energy storage; P ES Represents the active power of grid-type energy storage; Q ES Indicates the reactive power of grid-type energy storage; Indicates the grid voltage; Indicates the grid-connected voltage of the grid-type energy storage; Represents the current of grid-type energy storage. for is the conjugate complex number of ; Z represents the equivalent impedance of the grid-type energy storage.

[0147] Among them, the active power and reactive power of the grid-connected energy storage system can be expressed as:

[0148]

[0149] If Z cos φ=R, Z sin φ=X, where R is the resistance and X is the reactance, the active power and reactive power can be expressed as:

[0150]

[0151] The above formula can be simplified to:

[0152]

[0153] In the transmission line of the power grid, we usually think that the influence of resistance is negligible and can be ignored. At the same time, the power angle is also in a relatively small range. Therefore, sinδ≈δ, cosδ≈1. The above formula can be further simplified to:

[0154]

[0155] There is a direct and close connection between power angle and frequency. According to the above formula, it can be clearly seen that the grid-type energy storage system has the ability to dynamically adjust the power angle by regulating active power, thereby achieving frequency regulation. Similarly, it can also dynamically adjust the voltage by controlling reactive power.

[0156] In step 2, a power grid simulation digital model including grid-connected energy storage is constructed.

[0157] When constructing a power grid simulation model that includes grid-connected energy storage, the model needs to be constructed from two dimensions: static and transient.

[0158] In terms of the power grid static simulation model, its core components include:

[0159] (1) Line parameters: mainly including per-unit resistance value, per-unit reactance value, earth susceptance, rated current, and loop mark of parallel lines;

[0160] (2) Transformer parameters: mainly including leakage reactance, rated capacity, parallel line loop and fixed tap, etc.;

[0161] (3) Load model: mainly includes constant active load, constant reactive load, etc.;

[0162] (4) Thermal power units: mainly including actual active output, maximum active output, etc.;

[0163] (5) New energy units: mainly including actual active output, maximum active output, etc.;

[0164] (6) Grid-following / grid-building energy storage: mainly includes actual active output, maximum active output, etc.

[0165] In terms of power grid transient simulation model, its core components include:

[0166] (1) Line parameters: mainly including zero-sequence resistance per unit value, zero-sequence reactance per unit value, etc.

[0167] (2) Transformer parameters: mainly including zero-sequence reactance per unit value, etc.

[0168] (3) Transient control model of thermal power units;

[0169] (4) Transient control model of new energy units;

[0170] (5) Grid-following / grid-building energy storage transient control model.

[0171] In step 3, based on the different operating states of the grid-connected energy storage, grid operation mode data in various scenarios are generated.

[0172] Grid-connected energy storage, as an innovative means to improve the safety and stability of new power systems, is mainly responsible for accurately controlling and converting the electric energy in the energy storage system to ensure that the various needs of the power grid or load can be fully met. The working state of the energy storage inverter is more flexible and can be adaptively adjusted according to the real-time needs of the power grid. Specifically, the working state of the energy storage inverter can be roughly divided into three basic modes: charging state, discharging state and standby state.

[0173] The mathematical model of grid-type energy storage charging and discharging is as follows:

[0174]

[0175] In the formula, R t Indicates the current capacity; R ES Indicates system capacity; P ch Indicates charging power, in kW; η ch Indicates charging efficiency, %; P dis Indicates discharge power in kW; η dis Indicates discharge efficiency, %; ES SOC(t) represents the state of charge of the energy storage at time t; ES SOC(t-1) It represents the charge state of the grid-connected energy storage at time t-1.

[0176] Based on the different operating states of grid-type energy storage, multi-scenario operating mode data is generated including energy storage charging state, energy storage discharging state and energy storage standby state.

[0177] In step 4, based on data from different operating modes, grid safety and stability analysis indicators are proposed, and grid safety and stability analysis and short-circuit current verification are carried out for grid-connected energy storage scenarios.

[0178] Based on the data of grid-connected energy storage systems in different operating scenarios, in-depth grid transient stability analysis is required. Based on the system frequency response index and transient voltage fluctuation analysis index, a comprehensive evaluation of the transient stability of the power system including grid-connected energy storage is conducted.

[0179] (1) System frequency evaluation indicators:

[0180] The definition of the maximum frequency offset can be expressed as: after the active disturbance event occurs and during the implementation of a frequency regulation measure, when the system frequency undergoes a dynamic change, the difference between the lowest frequency point and the reference frequency is the maximum frequency offset. Its specific mathematical expression is as follows.

[0181] Δf1=f0-f1 (7)

[0182] Where Δf1 is the maximum frequency offset, in Hz; f0 is the system frequency corresponding to the lowest frequency point, in Hz; f1 is the system reference frequency, in Hz.

[0183] The maximum system frequency deviation accurately reflects the most significant impact of active disturbance on the system frequency. For power grids with voltage levels of 220kV and above, the frequency deviation must be strictly controlled within the range of ±0.2Hz to ensure the stability and safety of power grid operation.

[0184] (2) Transient voltage fluctuation evaluation index:

[0185] The definition of the system transient voltage fluctuation analysis index can be expressed as: the ratio of the sum of the absolute values ​​of the voltage deviations of each node to the total number of nodes within a specific analysis period, that is, the average value of the absolute values ​​of the voltage deviations of each node, and its expression is as follows:

[0186]

[0187] Where: ΔU1 is the system voltage deviation level, in kV; U q is the qth node voltage, in kV; U N is the node rated voltage, in kV; Z is the number of nodes.

[0188] The system transient voltage fluctuation analysis index is used to characterize the voltage deviation of the system as a whole. When the power grid is in normal operation mode, the voltage fluctuation amplitude of the power grid with a voltage level of 220kV and above must be strictly controlled within ±5% of the rated voltage; when the power grid is in an accident situation, the voltage fluctuation amplitude is limited to no more than ±10% of the rated voltage to ensure the stable operation and power supply quality of the power grid.

[0189] Based on the above transient stability analysis indicators, a safety and stability analysis is carried out on the operating mode data of grid-connected energy storage in different access scenarios to verify its safety and stability capabilities in different operating scenarios.

[0190] Short-circuit current verification is carried out based on the operating mode data of grid-connected energy storage in different access scenarios.

[0191] Embodiment 2:

[0192] The present invention also proposes a safety and stability analysis system 200 considering grid-type energy storage, such as Figure 2 As shown, including:

[0193] The first modeling unit 201 is used to construct a data analysis model of the grid-building energy storage for the grid to which the grid-building energy storage is connected;

[0194] A second modeling unit 202 is used to construct a power grid simulation digital model including grid-connected energy storage based on the mathematical analysis model;

[0195] A data generation unit 203 is used to determine different operating states of the grid-connected energy storage based on the grid simulation digital model, and generate grid operation mode data of multiple scenarios under the different operating states;

[0196] The analysis unit 204 is used to establish a power grid security and stability analysis index based on the power grid operation mode data, and perform a security and stability analysis on the power grid to which the grid-connected energy storage is connected based on the power grid security and stability analysis index.

[0197] Among them, the data analysis model of grid-type energy storage includes:

[0198] The relationship model between power, frequency and voltage of grid-type energy storage is as follows:

[0199]

[0200] in, is the grid voltage, is the grid-connected voltage of the grid-type energy storage, Q ES is the reactive power of the grid-type energy storage, X is the reactance, δ is the power angle, P ES It is the active power of grid-type energy storage.

[0201] Among them, the grid simulation digital model of grid-type energy storage includes:

[0202] Power grid static simulation model and power grid transient simulation model;

[0203] The power grid static simulation model comprises:

[0204] Line parameters, including: per-unit resistance value, per-unit reactance value, earth susceptance, rated current and loop mark of parallel lines;

[0205] Transformer parameters, including leakage reactance, rated capacity, parallel circuit loop and fixed tap;

[0206] Load model, including: constant active load model and constant reactive load model;

[0207] Thermal power units, including: actual active output and maximum active output;

[0208] New energy units, including: actual active output and maximum active output;

[0209] Grid-following / grid-building energy storage, including: actual active output and maximum active output;

[0210] The power grid transient simulation model comprises:

[0211] Line parameters, including: zero-sequence resistance per unit value and zero-sequence reactance per unit value;

[0212] Transformer parameters, including: zero-sequence reactance per unit value;

[0213] Transient control model of thermal power unit;

[0214] Transient control model of new energy units;

[0215] Grid-following / grid-building energy storage transient control model.

[0216] Among them, different operating states include:

[0217] Charging state, discharging state and standby state.

[0218] Among them, after determining the different operating states of the grid-type energy storage, a grid-type energy storage charging and discharging mathematical model is constructed, and based on the grid-type energy storage charging and discharging mathematical model, power grid operation mode data of various scenarios under different operating states are generated.

[0219] Among them, the model formula of the grid-type energy storage charging and discharging mathematical model is as follows:

[0220]

[0221] Among them, ES SOC(t) is the state of charge of the energy storage at time t, R t is the current capacity, R ES is the system capacity, ES SOC(t-1) is the state of charge of the grid-type energy storage at time t-1, P ch is the charging power, η ch is the charging efficiency, △t is a sampling period, P dis is the discharge power, η dis is the discharge efficiency.

[0222] Among them, the power grid security and stability analysis indicators include:

[0223] System frequency evaluation indicators and transient voltage fluctuation evaluation indicators.

[0224] Among them, the expression of the system frequency evaluation index is as follows:

[0225] Δf1=f0-f1

[0226] Among them, Δf1 is the maximum frequency offset, f0 is the system frequency corresponding to the lowest frequency point, and f1 is the system reference frequency.

[0227] Among them, the expression of transient voltage fluctuation evaluation index is as follows:

[0228]

[0229] Among them, ΔU1 is the system voltage deviation level, Z is the number of nodes, and U q is the qth node voltage, U N is the node rated voltage.

[0230] The analysis unit 204 is further used for:

[0231] According to the grid operation mode data, a short-circuit current check is performed on the grid to which the grid-connected energy storage is connected.

[0232] The present invention can take into account multiple safety constraints of the power grid, consider new power grid equipment such as grid-type energy storage, and take into account the change analysis of system frequency response and transient voltage fluctuation analysis indicators, thereby achieving comprehensiveness and safety in power grid safety and stability analysis.

[0233] Embodiment 3:

[0234] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding functions, so as to implement the steps of the method in the above embodiment.

[0235] Embodiment 4:

[0236] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both a built-in storage medium in a computer device and an extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the method in the above embodiment.

[0237] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The schemes in the embodiments of the present invention may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0238] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0239] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0240] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0241] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0242] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A safety and stability analysis method considering grid-type energy storage, characterized in that: include: Construct a data analysis model for grid-based energy storage for the grid to which grid-based energy storage is connected; Based on the mathematical analysis model, a power grid simulation digital model including grid-building energy storage is constructed; Based on the power grid simulation digital model, different operating states of the grid-connected energy storage are determined, and power grid operation mode data of multiple scenarios under the different operating states are generated; Based on the grid operation mode data, grid safety and stability analysis indicators are established, and based on the grid safety and stability analysis indicators, a safety and stability analysis is performed on the grid to which the grid-connected energy storage is connected.

2. The safety and stability analysis method according to claim 1, characterized in that: The data analysis model of the grid-type energy storage includes: The relationship model between power, frequency and voltage of grid-type energy storage is as follows: in, is the grid voltage, is the grid-connected voltage of the grid-type energy storage, Q ES is the reactive power of the grid-type energy storage, X is the reactance, δ is the power angle, P ES It is the active power of grid-type energy storage.

3. The safety and stability analysis method according to claim 1, characterized in that: The grid simulation digital model including grid-building energy storage includes: Power grid static simulation model and power grid transient simulation model; The power grid static simulation model comprises: Line parameters, including: per-unit resistance value, per-unit reactance value, earth susceptance, rated current and loop mark of parallel lines; Transformer parameters, including leakage reactance, rated capacity, parallel circuit loop and fixed tap; Load model, including: constant active load model and constant reactive load model; Thermal power units, including: actual active output and maximum active output; New energy units, including: actual active output and maximum active output; Grid-following / grid-building energy storage, including: actual active output and maximum active output; The power grid transient simulation model comprises: Line parameters, including: zero-sequence resistance per unit value and zero-sequence reactance per unit value; Transformer parameters, including: zero-sequence reactance per unit value; Transient control model of thermal power unit; Transient control model of new energy units; Grid-following / grid-building energy storage transient control model.

4. The safety and stability analysis method according to claim 1, characterized in that: The different operating states include: Charging state, discharging state and standby state.

5. The safety and stability analysis method according to claim 1, characterized in that: After determining the different operating states of the grid-type energy storage, a grid-type energy storage charging and discharging mathematical model is constructed, and based on the grid-type energy storage charging and discharging mathematical model, grid operation mode data of various scenarios under different operating states are generated.

6. The safety and stability analysis method according to claim 1, characterized in that: The model formula of the grid-type energy storage charging and discharging mathematical model is as follows: Among them, ES SOC(t) is the state of charge of the energy storage at time t, R t is the current capacity, R ES is the system capacity, ES SOC(t-1) is the state of charge of the grid-type energy storage at time t-1, P ch is the charging power, η ch is the charging efficiency, △t is a sampling period, P dis is the discharge power, η dis is the discharge efficiency.

7. The safety and stability analysis method according to claim 1, characterized in that: The power grid security and stability analysis indicators include: System frequency evaluation indicators and transient voltage fluctuation evaluation indicators.

8. The safety and stability analysis method according to claim 7, characterized in that: The expression of the system frequency evaluation index is as follows: Δf1=f0-f1 Among them, Δf1 is the maximum frequency offset, f0 is the system frequency corresponding to the lowest frequency point, and f1 is the system reference frequency.

9. The safety and stability analysis method according to claim 7, characterized in that: The expression of the transient voltage fluctuation evaluation index is as follows: Among them, ΔU1 is the system voltage deviation level, Z is the number of nodes, and U q is the qth node voltage, U N is the node rated voltage.

10. The safety and stability analysis method according to claim 1, characterized in that: The method further comprises: According to the grid operation mode data, a short-circuit current check is performed on the grid to which the grid-connected energy storage is connected.

11. A safety and stability analysis system considering grid-type energy storage, characterized in that: include: A first modeling unit is used to construct a data analysis model of the grid-building energy storage for the grid to which the grid-building energy storage is connected; A second modeling unit is used to construct a power grid simulation digital model including grid-building energy storage based on the mathematical analysis model; A data generation unit, used to determine different operating states of the grid-building energy storage based on the grid simulation digital model, and generate grid operation mode data of multiple scenarios under the different operating states; The analysis unit is used to establish a power grid safety and stability analysis index based on the power grid operation mode data, and to perform a safety and stability analysis on the power grid to which the grid-type energy storage is connected based on the power grid safety and stability analysis index.

12. The safety and stability analysis system according to claim 11, characterized in that: The data analysis model of the grid-type energy storage includes: The relationship model between power, frequency and voltage of grid-type energy storage is as follows: in, is the grid voltage, is the grid-connected voltage of the grid-type energy storage, Q ES is the reactive power of the grid-type energy storage, X is the reactance, δ is the power angle, P ES It is the active power of grid-type energy storage.

13. The safety and stability analysis system according to claim 11, characterized in that: The grid simulation digital model including grid-building energy storage includes: Power grid static simulation model and power grid transient simulation model; The power grid static simulation model comprises: Line parameters, including: per-unit resistance value, per-unit reactance value, earth susceptance, rated current and loop mark of parallel lines; Transformer parameters, including leakage reactance, rated capacity, parallel circuit loop and fixed tap; Load model, including: constant active load model and constant reactive load model; Thermal power units, including: actual active output and maximum active output; New energy units, including: actual active output and maximum active output; Grid-following / grid-building energy storage, including: actual active output and maximum active output; The power grid transient simulation model comprises: Line parameters, including: zero-sequence resistance per unit value and zero-sequence reactance per unit value; Transformer parameters, including: zero-sequence reactance per unit value; Transient control model of thermal power unit; Transient control model of new energy units; Grid-following / grid-building energy storage transient control model.

14. The safety and stability analysis system according to claim 11, characterized in that: The different operating states include: Charging state, discharging state and standby state.

15. The safety and stability analysis system according to claim 11, characterized in that: After determining the different operating states of the grid-type energy storage, a grid-type energy storage charging and discharging mathematical model is constructed, and based on the grid-type energy storage charging and discharging mathematical model, grid operation mode data of various scenarios under different operating states are generated.

16. The safety and stability analysis system according to claim 11, characterized in that: The model formula of the grid-type energy storage charging and discharging mathematical model is as follows: Among them, ES SOC(t) is the state of charge of the energy storage at time t, R t is the current capacity, R ES is the system capacity, ES SOC(t-1) is the state of charge of the grid-type energy storage at time t-1, P ch is the charging power, η ch is the charging efficiency, △t is a sampling period, P dis is the discharge power, η dis is the discharge efficiency.

17. The safety and stability analysis system according to claim 11, characterized in that: The power grid security and stability analysis indicators include: System frequency evaluation indicators and transient voltage fluctuation evaluation indicators.

18. The safety and stability analysis system according to claim 17, characterized in that: The expression of the system frequency evaluation index is as follows: Δf1=f0-f1 Among them, Δf1 is the maximum frequency offset, f0 is the system frequency corresponding to the lowest frequency point, and f1 is the system reference frequency.

19. The safety and stability analysis system according to claim 17, characterized in that: The expression of the transient voltage fluctuation evaluation index is as follows: Among them, ΔU1 is the system voltage deviation level, Z is the number of nodes, and U q is the qth node voltage, U N is the node rated voltage.

20. The safety and stability analysis system according to claim 11, characterized in that: The analysis unit is also used for: According to the grid operation mode data, a short-circuit current check is performed on the grid to which the grid-connected energy storage is connected.

21. A computer device, characterized in that: include: one or more processors; a processor for executing one or more programs; When the one or more programs are executed by the one or more processors, the method according to any one of claims 1 to 10 is implemented.

22. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the method according to any one of claims 1 to 10 is implemented.

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