Frequency stability analysis method and system of new energy power system considering photo-thermal inertia

Abstract

The application discloses a new energy power system frequency stability analysis method and system considering photothermal inertia, and belongs to the field of new energy power system frequency stability analysis. A simplified model of new energy power system frequency analysis considering inertia support and heat storage characteristics of photothermal power generation is established, from the perspective of control theory, the static and dynamic frequency stability of the new energy power system is analyzed based on the frequency domain and time domain analysis method of the system frequency transfer function, and corresponding quantitative analysis indexes are proposed, which can accurately quantitatively analyze the influence of new energy penetration rate and inertia support and heat storage characteristics of photothermal power generation on the system frequency stability.

Description

Technical Field

[0001] This invention relates to the field of frequency stability analysis of new energy power systems, and in particular to a method and system for frequency stability analysis of new energy power systems that considers photothermal inertia. Background Technology

[0002] In recent years, the penetration rate of new energy sources in the power system has been increasing year by year. However, most new energy sources such as photovoltaic and wind power are connected to the grid through power electronic devices, which cannot maintain stable coupling with the system frequency. When power disturbances occur, they cannot actively provide the necessary inertia support to the grid, greatly weakening the power system's inertia support capability. This low inertia characteristic is particularly pronounced for high-proportion new energy power systems with large load demands. When faced with accidents such as DC blocking or new energy unit disconnection, they cannot effectively resist disturbances, have poor frequency regulation and damping characteristics, and strong output uncertainty, making them highly susceptible to grid instability. Concentrating solar power (CSP), as a new energy power generation technology based on large-capacity thermal storage and power supply, has almost the same regulation characteristics as conventional thermal power units. It can provide strong rotational inertia support to the grid, providing feasibility for the future energy development strategy of achieving 100% renewable energy power supply across the entire grid.

[0003] However, there is currently little research on the stability of power systems containing solar thermal power generation. The stability mechanism of new energy power systems after taking into account the inertia support effect of solar thermal power generation and the thermal storage characteristics is still unclear. Therefore, it is necessary to establish a new energy power system containing solar thermal power generation that meets the requirements, and to analyze the system stability after the solar thermal power plant is connected to the grid based on the model. Summary of the Invention

[0004] The purpose of this invention is to provide a frequency stability analysis method and system for new energy power systems that considers solar thermal inertia, which can accurately quantify the impact of new energy penetration rate, solar thermal power generation inertia support, and thermal storage characteristics on system frequency stability.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A frequency stability analysis method for a new energy power system considering solar thermal inertia includes:

[0007] Establish a simplified frequency analysis model for new energy power systems that considers the inertia support of solar thermal power generation and the thermal storage characteristics;

[0008] Determine the system transfer function of the simplified frequency analysis model for the new energy power system;

[0009] The system frequency stability parameter margin is analyzed based on the system transfer function, and the system frequency stability parameter is made to meet the system frequency stability parameter margin, so that the new energy power system can achieve closed-loop stability.

[0010] Analysis of the static frequency characteristics of the system based on frequency domain analysis methods and system transfer function;

[0011] Analysis of the system's dynamic frequency response characteristics based on time-domain analysis methods and the system's static frequency characteristics;

[0012] The evaluation indicators are determined based on the system's static frequency characteristics and dynamic frequency response characteristics.

[0013] The impact of new energy penetration rate, solar thermal power generation inertia characteristics, and thermal storage characteristics on system frequency stability is quantified based on the evaluation indicators.

[0014] A frequency stability analysis system for a new energy power system considering solar thermal inertia, comprising:

[0015] The analysis model building module is used to build a simplified frequency analysis model for new energy power systems that takes into account the inertia support of solar thermal power generation and the thermal storage characteristics.

[0016] The system transfer function determination module is used to determine the system transfer function of the simplified frequency analysis model of the new energy power system.

[0017] The closed-loop stability module is used to analyze the system frequency stability parameter margin based on the system transfer function, and to ensure that the system frequency stability parameter meets the system frequency stability parameter margin, so that the new energy power system can achieve closed-loop stability.

[0018] The static frequency response analysis module is used to analyze the static frequency response of a system based on frequency domain analysis methods and the system transfer function.

[0019] The dynamic response characteristic analysis module is used to analyze the dynamic frequency response characteristics of the system based on time-domain analysis methods and the static frequency characteristics of the system.

[0020] The evaluation index determination module is used to determine the evaluation index based on the system's static frequency characteristics and dynamic frequency response characteristics.

[0021] The impact quantification module is used to quantify the impact of new energy penetration rate, solar thermal power generation inertia characteristics, and thermal storage characteristics on system frequency stability based on the evaluation indicators.

[0022] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0023] This invention discloses a frequency stability analysis method and system for new energy power systems considering solar thermal inertia. A simplified frequency analysis model for new energy power systems considering solar thermal power generation inertia support and thermal storage characteristics is established. From a control theory perspective, the static and dynamic frequency stability of the new energy power system is analyzed using frequency domain and time domain analysis methods based on the system frequency transfer function. Corresponding quantitative analysis indicators are proposed, which can accurately quantify the impact of new energy penetration rate and solar thermal power generation inertia support and thermal storage characteristics on system frequency stability. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A flowchart of a frequency stability analysis method for a new energy power system considering photothermal inertia, provided in an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of the frequency stability analysis method for a new energy power system considering photothermal inertia provided in an embodiment of the present invention;

[0027] Figure 3 A schematic diagram illustrating the changes in a system caused by load disturbances, provided in an embodiment of the present invention.

[0028] Figure 4 A schematic diagram of a conventional generator and load provided for an embodiment of the present invention;

[0029] Figure 5 A schematic diagram of a system frequency analysis response model for a traditional power system;

[0030] Figure 6 A schematic diagram illustrating the dynamic characteristics of a thermal storage system described by a first-order inertial element, provided for an embodiment of the present invention;

[0031] Figure 7 A simplified frequency analysis model of a new energy power system provided in an embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of a traditional new energy power system that includes solar thermal power generation.

[0033] Figure 9 A schematic diagram of the evaluation indicators provided in the embodiments of the present invention;

[0034] Figure 10This is a schematic diagram illustrating the frequency deviation variation under different solar thermal power generation penetration rates provided in an embodiment of the present invention;

[0035] Figure 11 This is a schematic diagram illustrating the variation of RoCoF under different solar thermal power generation penetration rates, as provided in an embodiment of the present invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] The purpose of this invention is to provide a frequency stability analysis method and system for new energy power systems that considers solar thermal inertia, which can accurately quantify the impact of new energy penetration rate, solar thermal power generation inertia support, and thermal storage characteristics on system frequency stability.

[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] This invention focuses on concentrated solar power (CSP) technology and addresses the frequency stability problem of new energy power systems. It establishes a frequency analysis model for new energy power systems that considers the inertia support of CSP and the thermal storage characteristics. From a control theory perspective, it analyzes the static and dynamic frequency stability of new energy power systems based on frequency domain and time domain analysis methods using the system frequency transfer function, and proposes corresponding quantitative analysis indicators. The invention also focuses on studying the mechanism by which CSP improves the frequency stability of new energy power systems.

[0040] like Figure 1 and Figure 2 As shown in the figure, an embodiment of the present invention provides a frequency stability analysis method for a new energy power system considering solar thermal inertia, comprising:

[0041] Step 1: Establish a simplified frequency analysis model for a new energy power system that considers the inertia support of solar thermal power generation and the thermal storage characteristics.

[0042] The traditional power system's system frequency response (SFR) model is a closed-loop control system that includes generators, loads, turbines, and governors.

[0043] When the system is subjected to load disturbance, it will cause the electromagnetic torque T output by the generator to be affected. e Changes in power lead to an imbalance between the system's mechanical and electromagnetic power, altering the generator's speed and affecting the system's frequency. Figure 3 is shown in the figure. Figure 3 , ΔP m is the variation of the system mechanical power.

[0044] The power system load is the sum of a series of electrical devices. Frequency fluctuations will cause the power of motor loads such as fans and pumps to change with the variation of the motor speed. For example, as shown in Figure 4 the figure, the correlation between the entire composite load and the frequency is as follows:

[0045] ΔP e =-ΔP L +DΔω r (1)

[0046] Ignoring non-linear links such as detailed governor control, turbine models, amplitude limiting and secondary frequency regulation, and taking the generator capacity as the reference, the system frequency analysis response model of the traditional power system is obtained as shown in Figure 5 the figure.

[0047] Figure 5 , ω ref is the reference value of the system electrical angular velocity; Δω r is the variation value of the electrical angular velocity of the system after being disturbed; ΔE is the frequency deviation; ΔP L is the variation of the active power of the load; M is the inertia time constant; D is the active power frequency response coefficient of the load; T is the equivalent inertia time constant of the turbine; a is the turbine characteristic coefficient, 0<a<1 for a steam turbine, and a=-2 for a hydraulic turbine; the governor is simplified and represented by a pure gain of 1 / R. ω ref , ΔP L , and Δω are all per-unit values.

[0048] To study the influence of the inertia support of concentrating solar power on the frequency stability of the new energy power system, the new energy penetration rate η is introduced. Assuming that the new energy penetration rate of the system is increased by replacing thermal power generating units in equal proportion, the new energy penetration rate η is:

[0049]

[0050] In the formula, P new is the generating power of the new energy unit, in MW; P sys_L is the system load power, in MW; η∈[0,1].

[0051] Further considering the process in which the heat storage system of concentrating solar power participates in the primary frequency regulation of the power grid, the relationship between the heat storage output ΔP ESS and Δω r is:

[0052] ΔP ESS =-K ESS Δω r (3)

[0053] Among them, K ESS The static power frequency characteristic coefficient of the thermal energy storage system is given by T. A first-order inertial element is used to describe the dynamic characteristics of the solar thermal power generation and thermal energy storage system, with a time constant of T. ESS ,like Figure 6 As shown.

[0054] First, the governor and turbine models are converted to the system load power benchmark. Then, the inertia support effect of renewable energy penetration and concentrated solar power (CSP) is considered in the generator and load models. By default, the inertia control effect of renewable energy units such as wind power and photovoltaic power is not considered. A simplified frequency analysis model of the renewable energy power system considering the inertia support of CSP is established, such as... Figure 7 As shown.

[0055] Figure 7 In this context, M′ represents the inertial time constant of the solar thermal power plant; K ESS This represents the static power-frequency characteristic coefficient of the solar thermal power plant's thermal storage system. This model specifically analyzes the supporting role of the inertia characteristics of solar thermal power generation and the thermal storage characteristics on the frequency stability of the new energy power system, and can effectively study the overall frequency characteristics of new energy power systems containing solar thermal power generation.

[0056] Step 2: Determine the system transfer function of the simplified frequency analysis model of the new energy power system.

[0057] Based on a simplified frequency analysis model of a new energy power system that considers the inertia support of solar thermal power generation and the characteristics of thermal storage, the closed-loop transfer function of the system can be obtained as follows:

[0058]

[0059] Among them, M g M is the inertial time constant of the system after the integration of new energy power generation. g = (1-η)M+M′. Therefore, the open-loop transfer function of the frequency analysis model of the new energy power system including solar thermal power generation can be further obtained as:

[0060]

[0061] Because the heat transfer process in a solar thermal power generation and thermal storage system is relatively slow in actual power systems, compared to the electrical components of a generator, there are T... ESS >>T, such as Figure 8 As shown.

[0062] Therefore, the open-loop transfer function of the frequency analysis model for a new energy power system considering the inertia support of solar thermal power generation and the thermal storage characteristics can be simplified to:

[0063]

[0064] Step 3: Analyze the system frequency stability parameter margin based on the system transfer function, and ensure that the system frequency stability parameter meets the system frequency stability parameter margin, so that the new energy power system achieves closed-loop stability.

[0065] The characteristic equation of a typical second-order system is:

[0066]

[0067] Where ζ is the system damping ratio, ω n It is the natural oscillation angular frequency.

[0068] Clearly, the established frequency analysis model is a second-order system, therefore:

[0069]

[0070] We can obtain:

[0071]

[0072] Based on Routh's theorem, the above characteristic equation is obtained through analysis, and the system frequency stability parameter T is derived. ESS K ESS M g Since D, η, and R are all greater than zero, the system can achieve closed-loop stability when the penetration rate of new energy satisfies 0 < η < 1 and the thermal power unit has sufficient frequency regulation capacity.

[0073] Step 4: Analyze the static frequency characteristics of the system based on frequency domain analysis methods and system transfer function.

[0074] Regarding the steady-state frequency characteristics, the frequency input ω is... ref For reference, the feedforward transfer function is 1, the open-loop transfer function is H(s), and the closed-loop transfer function is:

[0075]

[0076] Using the step response as the frequency input, i.e. According to the final value theorem, the steady-state frequency deviation E1 is:

[0077]

[0078] The active power disturbance ΔP of the load L For reference, the feedforward transfer function is: The open-loop transfer function is H(s), and the closed-loop transfer function is:

[0079]

[0080] The step response is used as the active power disturbance of the load, i.e. According to the final value theorem, the steady-state frequency deviation E2 is:

[0081]

[0082] Step 5: Analyze the dynamic frequency response characteristics of the system based on time-domain analysis methods and the static frequency characteristics of the system.

[0083] Further considering the dynamic frequency characteristics of the system under time-domain analysis, we first perform an inverse Laplace transform on G2(s) in steady state of equation (12) to obtain the dynamic frequency deviation time response ΔE(t) under load disturbance ΔE(t) = L -1 (ΔE), let but:

[0084]

[0085] According to the final value theorem, we have:

[0086]

[0087] Setting dΔE(t) / dt=0, we can obtain the time t when the frequency deviation reaches its maximum value, i.e., the time when the frequency change reaches its peak value. p Then the over-adjustment quantity M p for:

[0088]

[0089] 1) When the system is in an underdamped state, i.e., 0 < ζ < 1, the peak time corresponding to the extreme value of the frequency deviation is:

[0090]

[0091] The corresponding overshoot is:

[0092]

[0093] 2) When the system is in an overdamped state, i.e., ζ > 1, the peak time corresponding to the extreme value of the frequency deviation is:

[0094]

[0095] In the formula:

[0096]

[0097] The corresponding overshoot is:

[0098]

[0099] In the process of frequency stability analysis of a practical system, the peak time t corresponding to the extreme value of frequency deviation is... p and overshoot M p All of them can reflect the dynamic change process of frequency. According to equation (7), it can be found that they are all related to the penetration rate η of new energy and the inertia support capacity of solar thermal power generation.

[0100] Step 6: Determine the evaluation indicators based on the system's static frequency characteristics and dynamic frequency response characteristics.

[0101] Based on the established simplified frequency analysis model of the new energy power system, this invention proposes corresponding analysis indices, including steady-state frequency deviation indices E1 and E2, and system dynamic frequency analysis index β. d and the rate of change of frequency RoCoF, such as Figure 9 As shown.

[0102] Step 7: Quantify the impact of new energy penetration rate, solar thermal power generation inertia characteristics, and thermal storage characteristics on system frequency stability based on the evaluation indicators.

[0103] 1) For the steady-state frequency characteristics, frequency deviation indices E1 and E2 can be used for quantitative analysis. The steady-state frequency deviation indices E1 and E2 reflect the system's reference frequency ω, respectively. ref The system is affected by interference and load disturbance ΔP L The correlation between frequency deviation ΔE(∞) and the penetration rate of new energy sources, the inertia support capacity of solar thermal power generation, and thermal storage characteristics is obtained, thus revealing the impact of the inertia support and thermal storage characteristics of solar thermal power generation on the frequency stability of the new energy power system. Figure 10 As shown.

[0104] According to equation (11), if the system reference frequency ω ref If disturbed, then ΔE = ω ref -Δω r The larger the value of K, the larger the deviation of the system's steady-state frequency, E1. The steady-state frequency deviation E1 is closely related to the penetration rate of new energy sources, η, and the static power frequency characteristic coefficient of the solar thermal power generation and thermal storage system. The higher η is, the greater the deviation of K. ESS The larger the value, the larger E1, the worse the frequency stability of the new energy power system, and the lower the system's ability to maintain frequency synchronization after being disturbed.

[0105] According to equation (13), when the system is subjected to load disturbance ΔP L When, then ΔE=ω ref -Δω r The larger the value of K, the larger the system's frequency deviation E2 will be. The steady-state frequency deviation E2 is also closely related to the renewable energy penetration rate η and the static power frequency characteristic coefficient of the solar thermal power generation and storage system. The higher the renewable energy penetration rate, the larger the K value. ESSThe smaller the value, the larger the E2 value, and the worse the disturbance immunity of the new energy power system.

[0106] In summary, it can be found that the steady-state analysis index mainly quantifies the impact of renewable energy penetration rate on the frequency stability of renewable energy power systems including solar thermal power generation. The higher the renewable energy penetration rate, the worse the system frequency stability. Meanwhile, the static power frequency characteristic coefficient K of the solar thermal power generation and thermal storage system... ESS If the value is too large, the system's ability to maintain frequency synchronization after being disturbed will be insufficient. ESS If the value of K is too small, the system's ability to resist disturbances will be poor, so a suitable K needs to be selected. ESS This is important for improving the frequency stability of new energy power systems that include solar thermal power generation.

[0107] 2) The dynamic frequency characteristics of the system under time-domain analysis can be quantitatively analyzed using the system dynamic frequency response analysis index to assess the impact of the inertia support of solar thermal power generation on the frequency stability of the new energy power system. The dynamic frequency analysis index β... d This reflects the dynamic characteristics of frequency disturbance immunity of new energy power systems containing solar thermal power generation as the penetration rate of new energy and the inertia support capability of solar thermal power generation change.

[0108] The overall power / frequency characteristics of a power system depend on the combined effect of the descent rate characteristics of all generator governors, which in turn depends on the frequency characteristics of all loads in the system. Therefore, based on the traditional system frequency analysis model, the system load frequency response coefficient can be defined as:

[0109]

[0110] To further investigate the impact of the penetration rate of new energy sources such as concentrated solar power (CSP) on system frequency stability, dynamic frequency analysis indicators for analyzing the dynamic characteristics of new energy systems are defined based on the extreme values ​​of system dynamic frequency deviation and the system frequency response coefficient.

[0111]

[0112] Dynamic frequency analysis index β d The larger the value, the stronger the dynamic characteristics of the system's frequency resistance to disturbances.

[0113] 3) The frequency change rate RoCoF is the partial derivative of the system frequency with respect to time. It reflects the system's ability to resist sudden changes after the frequency of the new energy power system containing solar thermal power generation is disturbed. It can more intuitively reflect the inertia support capability of solar thermal power generation for the new energy system.

[0114] Based on the relationship of the inertial time constant of a power system: M = 2H, assuming f = 50Hz during normal operation, the maximum value of the rate of change of frequency RoCoF after the system is disturbed is R. max for:

[0115]

[0116] It is not difficult to see that when the load disturbance is constant, as the penetration rate of new energy sources increases, i.e., η continuously increases, the R after the disturbance... max It will continue to improve, and concentrated solar power will enhance the system's ability to support rotational inertia, and the R after disturbance... max It will continue to decline, and the specific changes are as follows: Figure 11 As shown.

[0117] Without changing the system's synchronous unit access capacity, as the penetration rate of concentrated solar power (CSP) continues to increase, the system's dynamic frequency deviation, overshoot, static frequency deviation, and rate of frequency change (RoCoF) all decrease. Therefore, CSP can significantly improve the frequency stability of the power system, providing practical and effective inertia support and frequency regulation, and enabling the system to quickly recover its frequency stability after being disturbed.

[0118] For power systems with a high proportion of renewable energy integration, most current research focuses on grid connection control of wind and solar power, with few studies analyzing the supporting role of solar thermal power plants in frequency stability of renewable energy power systems. This invention, based on a traditional power system frequency analysis model, considers the penetration rate of renewable energy (wind, solar, and solar thermal), the inertia characteristics of solar thermal power generation, and the thermal storage characteristics to establish a frequency analysis model for renewable energy power systems including solar thermal power generation. From a control theory perspective, based on frequency domain and time domain analysis methods using the system frequency transfer function, the static and dynamic frequency stability of the renewable energy power system is analyzed, and corresponding quantitative analysis indicators are proposed. This achieves an effective quantitative analysis of the mechanism by which solar thermal power generation affects the frequency stability of renewable energy power systems, and the model can be further applied to analyze the frequency stability of 100% renewable energy power systems.

[0119] This invention also provides a frequency stability analysis system for new energy power systems that considers solar thermal inertia, comprising:

[0120] The analysis model building module is used to build a simplified frequency analysis model for new energy power systems that takes into account the inertia support of solar thermal power generation and the thermal storage characteristics.

[0121] The system transfer function determination module is used to determine the system transfer function of the simplified frequency analysis model of the new energy power system.

[0122] The closed-loop stability module is used to analyze the system frequency stability parameter margin based on the system transfer function, and to ensure that the system frequency stability parameter meets the system frequency stability parameter margin, so that the new energy power system can achieve closed-loop stability.

[0123] The static frequency response analysis module is used to analyze the static frequency response of a system based on frequency domain analysis methods and the system transfer function.

[0124] The dynamic response characteristic analysis module is used to analyze the dynamic frequency response characteristics of the system based on time-domain analysis methods and the static frequency characteristics of the system.

[0125] The evaluation index determination module is used to determine the evaluation index based on the system's static frequency characteristics and dynamic frequency response characteristics.

[0126] The impact quantification module is used to quantify the impact of new energy penetration rate, solar thermal power generation inertia characteristics, and thermal storage characteristics on system frequency stability based on the evaluation indicators.

[0127] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0128] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A frequency stability analysis method for a new energy power system considering solar thermal inertia, characterized in that, include: Establish a simplified frequency analysis model for new energy power systems that considers the inertia support of solar thermal power generation and the thermal storage characteristics; Determine the system transfer function of the simplified frequency analysis model for the new energy power system; The system frequency stability parameter margin is analyzed based on the system transfer function, and the system frequency stability parameter is made to meet the system frequency stability parameter margin, so that the new energy power system can achieve closed-loop stability. Analysis of the static frequency characteristics of the system based on frequency domain analysis methods and system transfer function; Analysis of the system's dynamic frequency response characteristics based on time-domain analysis methods and the system's static frequency characteristics; The evaluation indicators are determined based on the system's static frequency characteristics and dynamic frequency response characteristics. The impact of new energy penetration rate, solar thermal power generation inertia characteristics, and thermal storage characteristics on system frequency stability is quantified based on the aforementioned evaluation indicators. The simplified frequency analysis model of the new energy power system includes: speed governor, turbine, synchronous unit access ratio module, solar thermal power generation unit, solar thermal power generation and thermal storage system, generator and load; The governor, turbine and synchronous generator are connected to the ratio module in sequence. After the frequency deviation is input to the governor, it is output as the change in mechanical power of the system through the turbine and synchronous generator connected to the ratio module. The input terminals of the generator and load are connected to the synchronous generator set, the solar thermal generator set, and the solar thermal power generation and storage system. The output terminals of the generator and load are connected to the solar thermal generator set, the solar thermal power generation and storage system, and the speed governor. The electromagnetic power change is obtained by adding the system mechanical power change, the inertial support of the solar thermal power generation output of the solar thermal generator set, the thermal storage output of the solar thermal power generation thermal storage system, and the negative value of the load active power change. The electromagnetic power change is input to the generator and the load, and the output is the change value of the electric angular velocity of the system after being disturbed. The solar thermal power generation unit is used to output the inertial support of the power output of the solar thermal power generation based on the change in electric angular velocity of the system after being disturbed; The solar thermal power generation and thermal storage system is used to output thermal storage output based on the change in electric angular velocity of the system after being disturbed; The frequency deviation is obtained by subtracting the change in the electric angular velocity of the system after being disturbed from the system's reference electric angular velocity value. The evaluation indicators are determined based on the system's static frequency characteristics and dynamic frequency response characteristics, specifically including: For the system's static frequency characteristics in steady state, the reference value of the system's electrical angular velocity in steady state is adopted. Frequency deviation as a reference and the change in active power of the load under steady state Frequency deviation as a reference As an evaluation indicator, this study aims to quantitatively analyze the impact of the inertia support and thermal storage characteristics of solar thermal power generation on the frequency stability of new energy power systems. To analyze the system's dynamic frequency response characteristics under time-domain analysis, system dynamic frequency analysis indicators are adopted. As an evaluation indicator, the impact of the inertia support of concentrated solar power generation on the frequency stability of the new energy power system is quantitatively analyzed; among them, , This refers to the dynamic frequency deviation time response. t For time, The peak time corresponds to the extreme value of the frequency deviation. For overshoot, 1 / R For the pure gain of the speed controller, D The active frequency response coefficient of the load. This refers to the static power-frequency characteristic coefficient of the thermal storage system. For the penetration rate of new energy; To reflect the inertia support capability of concentrated solar power (CSP) for new energy systems, the rate of change of frequency (RoCoF) is used as the evaluation index; where the maximum value of RoCoF is... for ;in, f For system frequency; The inertial time constant of the system after the integration of new energy power generation. , M The inertial time constant, M' This is the inertial time constant of the solar thermal power plant.

2. The frequency stability analysis method for new energy power systems considering solar and thermal inertia according to claim 1, characterized in that, The expression for the synchronous unit access ratio module is 1- η ; The expression for the solar thermal power generator set is: M's In the formula, It is a step response; The expression for the solar thermal power generation and thermal storage system is: In the formula, The time constant of a solar thermal power generation and thermal storage system; The expressions for the generator and load are as follows: .

3. The frequency stability analysis method for new energy power systems considering solar and thermal inertia according to claim 2, characterized in that, The system transfer function includes: closed-loop transfer function and open-loop transfer function; The closed-loop transfer function is: ； In the formula, This represents the change in the electric angular velocity of the system after being disturbed. This is the reference value for the system's electric angular velocity. G ( s ) is the forward channel transfer function. H ( s ) is the open-loop transfer function. a For turbine characteristic coefficients, T The equivalent inertial time constant of the turbine. This represents the change in active power of the load. The open-loop transfer function is: 。 4. The frequency stability analysis method for new energy power systems considering solar thermal inertia according to claim 3, characterized in that, The step of analyzing the system frequency stability parameter margin based on the system transfer function and ensuring that the system frequency stability parameter satisfies the system frequency stability parameter margin, thereby enabling the new energy power system to achieve closed-loop stability, specifically includes: By comparing the characteristic equations of a second-order system, the simplified frequency analysis model of the new energy power system is determined to be a second-order system, and satisfies... In the formula, For the system damping ratio, It is the natural oscillation angular frequency. ; Based on the open-loop transfer function, the characteristic equation of the simplified frequency analysis model of the new energy power system is determined as follows: ; Based on Routh's theorem, the characteristic equations of the simplified frequency analysis model of the new energy power system are analyzed to obtain the system frequency stability parameters. , , , D , η , R The margin is always greater than zero; When the penetration rate of new energy meets Furthermore, when the frequency regulation capacity of thermal power units meets the frequency regulation requirements, the new energy power system can achieve closed-loop stability.

5. The frequency stability analysis method for new energy power systems considering solar and thermal inertia according to claim 4, characterized in that, The analysis of the system's static frequency characteristics based on frequency domain analysis methods and system transfer functions specifically includes: system electric angular velocity reference value For reference, the feedforward transfer function is 1, and the open-loop transfer function is... In steady state, the system's electric angular velocity reference value Closed-loop transfer function as a reference G 1( s )for: ; Using the step response as the reference value for the system's electric angular velocity, and according to the final value theorem, the steady-state reference value for the system's electric angular velocity is obtained. Frequency deviation as a reference for: ; Changes in active power of the load For reference, the feedforward transfer function is: The open-loop transfer function is Under steady state, the change in active power of the load is the measure of the change in active power. Closed-loop transfer function as a reference G 2( s )for: ; Using the step response as the change in active power of the load, and according to the final value theorem, the change in active power of the load under steady state can be obtained. Frequency deviation as a reference for: .

6. The frequency stability analysis method for new energy power systems considering solar and thermal inertia according to claim 5, characterized in that, The analysis of the system's dynamic frequency response characteristics based on time-domain analysis methods and static frequency characteristics specifically includes: For steady-state changes in load active power Closed-loop transfer function as a reference Performing an inverse Laplace transform yields the dynamic frequency deviation time response under load disturbance. ;in, L -1 ( ) represents the inverse Laplace transform; make To obtain frequency deviation ; Based on the final value theorem and frequency deviation, determine ; make Then the over-adjustment amount is ; When the system is in an underdamped state, the peak time corresponding to the extreme value of the frequency deviation is: The corresponding overshoot is In the formula, t p1 This represents the peak time corresponding to the extreme value of the frequency deviation in the underdamped state. M p1 This is the overshoot in the underdamped state; When the system is in an overdamped state, the peak time corresponding to the extreme value of the frequency deviation is: The corresponding overshoot is In the formula, t p2 This represents the peak time corresponding to the extreme value of the frequency deviation under overdamped conditions. M p2 This is the overshoot amount in the overdamped state; a 0 is the first intermediate variable. b 0 is the second intermediate variable. .

7. The frequency stability analysis method for new energy power systems considering solar and thermal inertia according to claim 6, characterized in that, The impact of renewable energy penetration rate, solar thermal power generation inertia characteristics, and thermal storage characteristics on system frequency stability is quantified based on the aforementioned evaluation indicators, specifically including: Based on the system's electric angular velocity reference value under steady state Frequency deviation as a reference and the change in active power of the load under steady state Frequency deviation as a reference The higher the penetration rate of new energy sources, the worse the system frequency stability, and the higher the static power frequency characteristic coefficient of the thermal storage system. The larger the frequency, the worse the frequency stability of the new energy power system, and the lower its ability to maintain frequency synchronization after being disturbed. The smaller the frequency, the weaker the disturbance immunity of the renewable energy power system. Therefore, in order to improve the frequency stability of renewable energy power systems including solar thermal power generation, it is necessary to select appropriate [specific technologies / methods]. ; Based on system dynamic frequency analysis indicators To obtain the dynamic frequency analysis index of the system The larger the value, the stronger the dynamic characteristics of the system frequency in resisting disturbances; Based on the frequency change rate RoCoF, we obtain the following changes in load after disturbance as the penetration rate of new energy sources increases, given a constant load disturbance: It will continue to improve; concentrated solar power (CSP) will enhance the system's ability to support rotational inertia after disturbances. It will continue to decline.

8. A frequency stability analysis system for a new energy power system considering solar thermal inertia, characterized in that, include: The analysis model building module is used to build a simplified frequency analysis model for new energy power systems that takes into account the inertia support of solar thermal power generation and the thermal storage characteristics. The system transfer function determination module is used to determine the system transfer function of the simplified frequency analysis model of the new energy power system. The closed-loop stability module is used to analyze the system frequency stability parameter margin based on the system transfer function, and to ensure that the system frequency stability parameter meets the system frequency stability parameter margin, so that the new energy power system can achieve closed-loop stability. The static frequency response analysis module is used to analyze the static frequency response of a system based on frequency domain analysis methods and the system transfer function. The dynamic response characteristic analysis module is used to analyze the dynamic frequency response characteristics of the system based on time-domain analysis methods and the static frequency characteristics of the system. The evaluation index determination module is used to determine the evaluation index based on the system's static frequency characteristics and dynamic frequency response characteristics. The impact quantification module is used to quantify the impact of new energy penetration rate, solar thermal power generation inertia characteristics and thermal storage characteristics on system frequency stability based on the evaluation indicators. The simplified frequency analysis model of the new energy power system includes: speed governor, turbine, synchronous unit access ratio module, solar thermal power generation unit, solar thermal power generation and thermal storage system, generator and load; The governor, turbine and synchronous generator are connected to the ratio module in sequence. After the frequency deviation is input to the governor, it is output as the change in mechanical power of the system through the turbine and synchronous generator connected to the ratio module. The input terminals of the generator and load are connected to the synchronous generator set, the solar thermal generator set, and the solar thermal power generation and storage system. The output terminals of the generator and load are connected to the solar thermal generator set, the solar thermal power generation and storage system, and the speed governor. The electromagnetic power change is obtained by adding the system mechanical power change, the inertial support of the solar thermal power generation output of the solar thermal generator set, the thermal storage output of the solar thermal power generation thermal storage system, and the negative value of the load active power change. The electromagnetic power change is input to the generator and the load, and the output is the change value of the electric angular velocity of the system after being disturbed. The solar thermal power generation unit is used to output the inertial support of the power output of the solar thermal power generation based on the change in electric angular velocity of the system after being disturbed; The solar thermal power generation and thermal storage system is used to output thermal storage output based on the change in electric angular velocity of the system after being disturbed; The frequency deviation is obtained by subtracting the change in the electric angular velocity of the system after being disturbed from the system's reference electric angular velocity value. The evaluation indicators are determined based on the system's static frequency characteristics and dynamic frequency response characteristics, specifically including: For the system's static frequency characteristics in steady state, the reference value of the system's electrical angular velocity in steady state is adopted. Frequency deviation as a reference and the change in active power of the load under steady state Frequency deviation as a reference As an evaluation indicator, this study aims to quantitatively analyze the impact of the inertia support and thermal storage characteristics of solar thermal power generation on the frequency stability of new energy power systems. To analyze the system's dynamic frequency response characteristics under time-domain analysis, system dynamic frequency analysis indicators are adopted. As an evaluation indicator, the impact of the inertia support of concentrated solar power generation on the frequency stability of the new energy power system is quantitatively analyzed; among them, , This refers to the dynamic frequency deviation time response. t For time, The peak time corresponds to the extreme value of the frequency deviation. For overshoot, 1 / R For the pure gain of the speed controller, D The active frequency response coefficient of the load. This refers to the static power-frequency characteristic coefficient of the thermal storage system. For the penetration rate of new energy; To reflect the inertia support capability of concentrated solar power (CSP) for new energy systems, the rate of change of frequency (RoCoF) is used as the evaluation index; where the maximum value of RoCoF is... for ;in, f For system frequency; The inertial time constant of the system after the integration of new energy power generation. , M The inertial time constant, M' This is the inertial time constant of the solar thermal power plant.

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