Hybrid energy storage regulation and control method and system, storage medium and equipment

Abstract

The embodiment of the invention discloses a hybrid energy storage regulation and control method, and the method comprises the steps: obtaining a corresponding frequency modulation transfer function Uhuo (S) based on a primary frequency modulation model of a conventional thermal power generating unit; acquiring a corresponding energy storage transfer function I (s) based on the energy storage primary frequency modulation general control model; determining a primary frequency modulation dynamic model according to the frequency modulation transfer function Uhuo (S) and the energy storage transfer function I (s); determining output power and frequency deviation corresponding to VIR control and VDR control in combination with the primary frequency modulation dynamic model; and determining the hybrid energy storage output power according to the output power and the frequency deviation corresponding to the VIR control and the VDR control. The power type energy storage super capacitor with high power responds to an inertia control signal, and the lithium battery with high capacity responds to a droop control signal, so that VIR and VDR are matched with output characteristics of different types of energy storage, the frequency difference is effectively reduced, and frequency deterioration is hindered.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid energy storage regulation and control, and in particular to a hybrid energy storage regulation and control method, system, storage medium and device. Background Art

[0002] With the growing demand for energy, the environmental pollution problem caused by the burning of fossil resources is becoming increasingly serious; therefore, vigorously developing renewable low-carbon energy such as wind, solar and hydrogen has become an inevitable trend worldwide, while the source-load mismatch problem has become increasingly prominent, bringing severe challenges to the frequency adjustment of the power system.

[0003] In this context, energy storage systems have become an indispensable part of the safety and stability of the power system due to their chargeable and dischargeable features and rapid power response. Energy storage systems are widely used in various links of the power system. They can not only participate in peak load regulation and frequency regulation, but also effectively smooth out the power fluctuations of renewable energy, thereby ensuring the safety and stability of the power system after large-scale wind and solar power and other renewable energy are connected to the grid.

[0004] In the field of primary frequency regulation of power systems, the application of energy storage systems is particularly critical. Since the time scale of primary frequency regulation of power systems is highly consistent with the response time of energy storage equipment, the use of energy storage to assist conventional units in participating in primary frequency regulation of power systems has become a research focus of many scholars. Among them, electrochemical energy storage based on lithium batteries has been widely adopted by experts and scholars due to its mature technology and high degree of scale. Summary of the invention

[0005] Based on this, it is necessary to propose a hybrid energy storage control method to address the above problems.

[0006] A hybrid energy storage control method, the method comprising the following steps:

[0007] Based on the primary frequency regulation model of conventional thermal power units, the corresponding frequency regulation transfer function U is obtained. huo (S);

[0008] Based on the universal control model of energy storage primary frequency modulation, the corresponding energy storage transfer function I(s) is obtained;

[0009] According to the frequency modulation transfer function U huo (S), the energy storage transfer function I(s) determines a primary frequency modulation dynamic model;

[0010] Determine the output power and frequency deviation corresponding to VIR control and VDR control in combination with the primary frequency modulation dynamic model;

[0011] The hybrid energy storage output power is determined according to the output power and frequency deviation corresponding to the VIR control and the VDR control.

[0012] In the above scheme, based on the primary frequency modulation model of conventional thermal power units, the corresponding frequency modulation transfer function U is obtained. huo (S), specifically including:

[0013]

[0014] Among them, R g is the time constant of the thermal power unit speed regulator; R ch is the turbine time constant; R rh is the heater time constant; E hp is the heater gain.

[0015] In the above scheme, the acquisition of the corresponding energy storage transfer function I(s) based on the energy storage primary frequency modulation general control model includes:

[0016]

[0017] Among them, R b,i is the energy storage time constant;

[0018] The energy storage transfer function I(s) is evaluated according to the energy storage state of charge SOC:

[0019]

[0020] Among them, S OCk is the energy storage SOC at time t; S OC0 is the energy storage SOC at the initial moment; ΔT is a frequency modulation cycle; P b is the energy storage output power; E rate is the total capacity of the energy storage system.

[0021] In the above scheme, the frequency modulation transfer function U huo (S), the energy storage transfer function I(s) determines a primary frequency modulation dynamic model, specifically including:

[0022] ΔP huo (s)=-Δf(s)·H huo ·U huo (s)

[0023] ΔP huo (s)+ΔP b (s)-ΔP L (s)=(2Q·s+D)·Δf(s)

[0024] Among them, H huo The primary unit adjustment power of the thermal power unit; U huo (S) is the frequency transfer function; D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; ΔP huo (s), ΔPb (s) are the output power of thermal power units and energy storage respectively.

[0025] In the above scheme, the determination of the output power and frequency deviation corresponding to the VIR control and the VDR control in combination with the primary frequency modulation dynamic model specifically includes:

[0026] When the energy storage battery adopts VIR control, its output power and corresponding frequency deviation are:

[0027]

[0028]

[0029] in, is the inertia coefficient when the energy storage adopts VIR control; I(s) is the energy storage transfer function; D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit;

[0030] When the energy storage battery adopts VDR control, its output power and corresponding frequency deviation are:

[0031]

[0032]

[0033] in, is the droop coefficient when energy storage adopts VDC control; I(s) is the energy storage transfer function; D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit.

[0034] In the above scheme, the output power and frequency deviation corresponding to VIR control and VDR control are determined in combination with the primary frequency modulation dynamic model, and then the method further includes: obtaining the initial frequency change rate and steady-state frequency deviation corresponding to VIR control and VDR control:

[0035] Corresponding initial frequency change rate when using VIR control and steady-state frequency deviation for:

[0036]

[0037] Where D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; Δf VIR (s) is the frequency deviation corresponding to VIR control;

[0038] The corresponding initial frequency change rate when VDR control is used and steady-state frequency deviation for:

[0039]

[0040] Among them, D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; is the steady-state frequency deviation.

[0041] In the above scheme, the hybrid energy storage output power is determined according to the output power and frequency deviation corresponding to the VIR control and the VDR control, specifically including:

[0042] The power type energy storage is determined according to the energy storage power instruction under VIR control, and the energy type energy storage is determined according to the energy storage power instruction under VDR control:

[0043]

[0044] Among them, ΔP b,gl (s), ΔP b,nl (s) are the output power of power type and energy type energy storage respectively; I gl (s), I nl (s) are the frequency modulation transfer functions of power type and energy type energy storage, respectively.

[0045] In the above scheme, the hybrid energy storage output power is determined according to the output power and frequency deviation corresponding to the VIR control and the VDR control. After that, the method further includes obtaining the frequency control deviation:

[0046]

[0047] Where D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; I gl (s), I nl (s) are the frequency modulation transfer functions of power type and energy type energy storage, respectively; U huo (S) is the frequency modulation transfer function.

[0048] The present application also proposes a hybrid energy storage control system based on VIR and VDR, the system comprising: a transfer function acquisition unit, a frequency modulation dynamic model construction unit, an output power and frequency deviation acquisition unit and a hybrid energy storage output power determination unit;

[0049] The transfer function acquisition unit is used to acquire the corresponding frequency modulation transfer function U based on the primary frequency modulation model of the conventional thermal power unit. huo (S); Based on the general control model of energy storage primary frequency modulation, obtain the corresponding energy storage transfer function I(s);

[0050] The frequency modulation dynamic model building unit is used to build a frequency modulation dynamic model based on the frequency modulation transfer function U huo (S), the energy storage transfer function I(s) determines a primary frequency modulation dynamic model;

[0051] The output power and frequency deviation acquisition unit is used to determine the output power and frequency deviation corresponding to the VIR control and the VDR control in combination with the primary frequency modulation dynamic model;

[0052] The hybrid energy storage output power determination unit is used to determine the hybrid energy storage output power according to the output power and frequency deviation corresponding to the VIR control and VDR control.

[0053] The present application also proposes a readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the following steps:

[0054] Based on the primary frequency regulation model of conventional thermal power units, the corresponding frequency regulation transfer function U is obtained. huo (S);

[0055] Based on the universal control model of energy storage primary frequency modulation, the corresponding energy storage transfer function I(s) is obtained;

[0056] According to the frequency modulation transfer function U huo (S), the energy storage transfer function I(s) determines a primary frequency modulation dynamic model;

[0057] Determine the output power and frequency deviation corresponding to VIR control and VDR control in combination with the primary frequency modulation dynamic model;

[0058] The hybrid energy storage output power is determined according to the output power and frequency deviation corresponding to the VIR control and the VDR control.

[0059] The present application also proposes a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the following steps of the computer program:

[0060] Based on the primary frequency regulation model of conventional thermal power units, the corresponding frequency regulation transfer function U is obtained. huo (S);

[0061] Based on the universal control model of energy storage primary frequency modulation, the corresponding energy storage transfer function I(s) is obtained;

[0062] According to the frequency modulation transfer function U huo (S), the energy storage transfer function I(s) determines a primary frequency modulation dynamic model;

[0063] Determine the output power and frequency deviation corresponding to VIR control and VDR control in combination with the primary frequency modulation dynamic model;

[0064] The hybrid energy storage output power is determined according to the output power and frequency deviation corresponding to the VIR control and the VDR control.

[0065] The embodiment of the present invention has the following beneficial effects: based on the primary frequency modulation model of a conventional thermal power unit, the corresponding frequency modulation transfer function U huo (S); Based on the energy storage primary frequency modulation general control model, obtain the corresponding energy storage transfer function I(s); According to the frequency modulation transfer function U huo (S), the energy storage transfer function I(s) determines the primary frequency modulation dynamic model; the output power and frequency deviation corresponding to VIR control and VDR control are determined in combination with the primary frequency modulation dynamic model; the hybrid energy storage output power is determined according to the output power and frequency deviation corresponding to VIR control and VDR control. The present invention makes a high-power power-type energy storage supercapacitor respond to an inertial control signal, and a high-capacity lithium battery respond to a droop control signal, so that VIR and VDR are consistent with the output characteristics of different types of energy storage, effectively reducing the frequency difference and preventing frequency deterioration, and maintaining the normal operation of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0067] in:

[0068] Figure 1 A schematic diagram of a hybrid energy storage control method in an embodiment;

[0069] Figure 2 It is a schematic diagram of system frequency deviation under typical step disturbance;

[0070] Figure 3 It is a schematic diagram of the output power of thermal power units under typical step disturbance;

[0071] Figure 4 Schematic diagram of hybrid energy storage output power under typical step disturbance;

[0072] Figure 5 Schematic diagram of hybrid energy storage SOC under typical step disturbance. DETAILED DESCRIPTION

[0073] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0074] In the following description, a large number of specific details are given in order to provide a more thorough understanding of the present invention; however, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details; in other examples, in order to avoid confusion with the present invention, some technical features known in the art are not described, and it should be understood that the present invention can be implemented in different forms and should not be interpreted as limited to the embodiments presented here; on the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present invention to those skilled in the art.

[0075] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present invention. When used herein, the singular forms "a", "an" and "said / the" are also intended to include the plural forms, unless the context clearly indicates otherwise, and it should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0076] The existing control strategies for energy storage participating in the primary frequency regulation of power systems are mostly based on two mechanisms: Virtual Inertial Response (VIR) and Virtual Droop Response (VDR). VIR simulates the inertial response characteristics of conventional units and can quickly suppress the initial rate of change of frequency; while VDR focuses on the frequency deviation itself and improves the steady-state frequency deviation of the system by adjusting the output power of energy storage. However, most existing strategies only consider one virtual control strategy, or simply superimpose VIR and VDR, ignoring the inherent frequency regulation mechanism of the two.

[0077] Specifically, VIR focuses on supporting the system inertia, is proportional to the rate of change of the frequency deviation, and can quickly suppress the initial frequency drop, but cannot improve the system's steady-state frequency deviation; while VDR focuses on the frequency deviation itself, is proportional to the size of the frequency deviation value, and can improve the steady-state frequency deviation, but has limited effect on suppressing the initial frequency change rate; therefore, when a single energy storage system participates in frequency regulation, it is often unable to simultaneously meet the control requirements for the initial frequency change rate and the steady-state frequency deviation.

[0078] In addition, different types of energy storage systems have different power and capacity characteristics. Power-type energy storage systems (such as supercapacitors) have the characteristics of high power density and rapid response to frequency change signals, which are suitable for VIR control; while energy-type energy storage systems (such as lithium batteries) have high energy density and can provide stable power output for a long time, which are suitable for VDR control; however, existing strategies often fail to fully utilize the advantages of these two energy storage systems, resulting in unsatisfactory frequency regulation effects.

[0079] In summary, in order to overcome the shortcomings of the existing energy storage participating in the primary frequency regulation strategy of the power system, the present invention proposes an adaptive VIR and VDR coordinated control method for hybrid energy storage participating in primary frequency regulation. This method reasonably combines the energy storage output mechanism of VIR and VDR, and selects the appropriate energy storage type (i.e., power-type energy storage and energy-type energy storage) according to the requirements of the two for energy storage power and capacity, so as to achieve the best frequency regulation effect.

[0080] In order to thoroughly understand the present invention, a detailed structure will be presented in the following description to illustrate the technical solution proposed by the present invention; optional embodiments of the present invention are described in detail as follows, but in addition to these detailed descriptions, the present invention may also have other implementation methods.

[0081] like Figure 1 As shown, in one embodiment, a hybrid energy storage control method is provided, and the hybrid energy storage control method includes steps S101 to S105, which are described in detail as follows:

[0082] S101, based on the primary frequency regulation model of conventional thermal power units, obtain the corresponding frequency regulation transfer function U huo (S);

[0083] By constructing a primary frequency regulation model for conventional thermal power units, the dynamic response characteristics of the thermal power units during the frequency regulation process can be accurately simulated, including the behavior of the governor and the reheat turbine. The necessary system dynamic basic data for the subsequent frequency regulation control of the energy storage system can then be obtained based on the model to ensure that the energy storage system can work more effectively with the thermal power units.

[0084] In some embodiments, based on the primary frequency modulation model of a conventional thermal power unit, the corresponding frequency modulation transfer function U is obtained. huo (S), specifically including:

[0085]

[0086] Among them, R g is the time constant of the thermal power unit speed regulator; R ch is the turbine time constant; R rh is the heater time constant; E hp is the heater gain.

[0087] Specifically, the primary frequency regulation model of the regional power system containing energy storage includes a primary frequency regulation model of conventional thermal power units and a general control model of primary frequency regulation of energy storage. This application uses thermal power units with larger capacity as conventional frequency regulation units, and mainly considers the governor and reheat turbine in the frequency regulation process.

[0088] S102, based on the energy storage primary frequency modulation general control model, obtaining the corresponding energy storage transfer function I(s);

[0089] Due to its fast response characteristics, the energy storage system uses the first-order inertia link to equivalent its output characteristics, which can quickly respond to system frequency changes. The introduction of energy storage state of charge (SOC) to evaluate the remaining frequency regulation capacity of energy storage helps to grasp the status of the energy storage system in real time and ensure its effectiveness and sustainability in the frequency regulation process.

[0090] In some embodiments, based on the energy storage primary frequency modulation general control model, obtaining the corresponding energy storage transfer function I(s) includes:

[0091]

[0092] Among them, R b,i is the energy storage time constant;

[0093] The energy storage transfer function I(s) is evaluated according to the energy storage state of charge SOC:

[0094]

[0095] Among them, S OCk is the energy storage SOC at time t; S OC0 is the energy storage SOC at the initial moment; ΔT is a frequency modulation cycle; P b is the energy storage output power; E rate is the total capacity of the energy storage system.

[0096] Specifically, for the general control model of primary frequency regulation of energy storage, compared with conventional frequency regulation units, in order to reflect the rapid response characteristics of energy storage, a first-order inertia link is generally used to equivalent its output characteristics.

[0097] S103, according to the frequency modulation transfer function U huo (S), energy storage transfer function I(s) determines the primary frequency modulation dynamic model;

[0098] Combining the dynamic models of thermal power units and energy storage systems, a dynamic model of primary frequency regulation of the regional power system with energy storage was constructed, which can fully reflect the frequency response characteristics of the system under load disturbances, and provide a solid analytical basis for the formulation of subsequent VIR and VDR control strategies, ensuring the scientificity and rationality of the control strategies.

[0099] In some embodiments, according to the frequency modulation transfer function U huo (S), energy storage transfer function I(s) determine the primary frequency modulation dynamic model, which specifically includes:

[0100] ΔP huo (s)=-Δf(s)·H huo ·U huo (s)

[0101] ΔP huo (s)+ΔP b (s)-ΔP L (s)=(2Q·s+D)·Δf(s)

[0102] Among them, H huo The primary unit adjustment power of the thermal power unit; U huo (S) is the frequency transfer function; D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; ΔP huo (s), ΔP b (s) are the output power of thermal power units and energy storage respectively.

[0103] Specifically, when a load disturbance occurs in the system, the system frequency will change suddenly. Therefore, it is necessary to use a primary frequency regulation dynamic model of the regional power system with energy storage.

[0104] S104, determining the output power and frequency deviation corresponding to VIR control and VDR control in combination with the primary frequency modulation dynamic model;

[0105] The energy storage output power and frequency deviation under VIR and VDR control are determined respectively, so that the energy storage system can flexibly adjust its output power according to different control requirements; among them, VIR focuses on suppressing the initial frequency change rate, while VDR focuses on improving the steady-state frequency deviation. The combination of the two can significantly improve the frequency regulation effect of the system.

[0106] In some embodiments, the output power and frequency deviation corresponding to the VIR control and the VDR control are determined in combination with the primary frequency modulation dynamic model, specifically including:

[0107] When the energy storage battery adopts VIR control, its output power and corresponding frequency deviation are:

[0108]

[0109]

[0110] in, is the inertia coefficient when the energy storage adopts VIR control; I(s) is the energy storage transfer function; D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit;

[0111] When the energy storage battery adopts VDR control, its output power and corresponding frequency deviation are:

[0112]

[0113]

[0114] in, is the droop coefficient when energy storage adopts VDC control; I(s) is the energy storage transfer function; D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit.

[0115] In some embodiments, the output power and frequency deviation corresponding to the VIR control and the VDR control are determined in combination with the primary frequency modulation dynamic model, and then the following steps are further included: obtaining the initial frequency change rate and the steady-state frequency deviation corresponding to the VIR control and the VDR control:

[0116] Corresponding initial frequency change rate when using VIR control and steady-state frequency deviation for:

[0117]

[0118] Where D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; Δf VIR (s) is the frequency deviation corresponding to VIR control;

[0119] The corresponding initial frequency change rate when VDR control is used and steady-state frequency deviation for:

[0120]

[0121] Among them, D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; is the steady-state frequency deviation.

[0122] Specifically, when VIR is used, the initial frequency change rate Under system load disturbance, it depends on the inertia coefficient Q of the thermal power unit itself and the virtual inertia coefficient of energy storage. Steady-state frequency deviation Then It is irrelevant. Therefore, VIR can quickly suppress the initial frequency change rate, but cannot improve the system steady-state frequency deviation. When VDR is used, It depends only on the Q of the thermal power unit itself; It also depends on H huo and It can be seen that VDR can improve the steady-state frequency deviation, but has no effect on the initial frequency difference change rate.

[0123] Furthermore, the use of VDR in energy storage can effectively improve the frequency modulation effect throughout the frequency modulation cycle, while the use of VIR can only restore the frequency deviation before the frequency reaches the lowest point, and will inhibit the frequency recovery after the frequency deviation reaches the maximum value. Therefore, it is necessary to combine the frequency modulation characteristics of different types of energy storage and select appropriate frequency modulation control methods for them to achieve the control effects of both.

[0124] S105. Determine the hybrid energy storage output power according to the output power and frequency deviation corresponding to the VIR control and the VDR control.

[0125] According to the requirements of VIR and VDR control, the energy storage power instructions are reasonably allocated to different types of energy storage devices (such as power-type energy storage supercapacitors and energy-type energy storage lithium batteries), so that different types of energy storage devices can give full play to their advantages. Power-type energy storage supercapacitors can respond quickly to VIR signals and suppress frequency drops; while energy-type energy storage lithium batteries can perform long-term droop power responses and improve the system's steady-state frequency deviation. This allocation method enables the hybrid energy storage system to participate more effectively in the primary frequency regulation of the power system and improve the stability and reliability of the system.

[0126] Specifically, the most commonly used and most mature energy storage method is energy-type energy storage, which is characterized by high energy density and low power density. Power-type energy storage is rarely used in the field of frequency modulation. Its characteristics are high power density and low energy density. This is because its cost is high and its capacity is small, and it is not suitable for the severe load disturbances of today's system. Power-type energy storage is suitable for VIR due to its high power density and rapid response to frequency change signals. Energy-type energy storage is suitable for VDR because of its high energy density, which can leave sufficient frequency modulation margin to perform frequency modulation tasks throughout the frequency modulation cycle. Therefore, a hybrid energy storage type can be selected based on the needs of VDR and VIR.

[0127] In some embodiments, the hybrid energy storage output power is determined according to the output power and frequency deviation corresponding to the VIR control and the VDR control, specifically including:

[0128] The power type energy storage is determined according to the energy storage power instruction under VIR control, and the energy type energy storage is determined according to the energy storage power instruction under VDR control:

[0129]

[0130] Where ΔP b,gl (s), ΔP b,nl (s) are the output power of power type and energy type energy storage respectively; I gl (s), I nl (s) are the frequency modulation transfer functions of power type and energy type energy storage, respectively.

[0131] In some embodiments, the hybrid energy storage output power is determined according to the output power and frequency deviation corresponding to the VIR control and the VDR control. After that, the method further includes obtaining the frequency control deviation:

[0132]

[0133] Where D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; I gl (s), I nl (s) are the frequency modulation transfer functions of power type and energy type energy storage, respectively; U huo (S) is the frequency modulation transfer function.

[0134] Furthermore, the initial frequency change rate can be calculated and steady-state frequency deviation

[0135]

[0136] Where D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; H huo Adjust the power of the primary unit of the thermal power unit.

[0137] Specifically, the key parameters used in the above embodiments and their corresponding values ​​are:

[0138] Q: Inertia coefficient of thermal power unit, the value is 5.

[0139] D: System damping coefficient, the value is 1.

[0140] H huo : The primary unit regulation power of the thermal power unit, the value is 20.

[0141] The virtual inertia coefficients are 12 and 24 respectively.

[0142] R g : Time constant of thermal power unit speed regulator, the value is 0.1.

[0143] E hp : Heater gain, the value is 0.5.

[0144] R ch , R rh : represent the turbine time constant and heater time constant, with values ​​of 0.3 and 10 respectively.

[0145] In summary, the hybrid energy storage control method proposed in this application determines the primary frequency regulation dynamic model by constructing an accurate model of conventional thermal power units and energy storage systems, and combines VIR and VDR control strategies to reasonably allocate energy storage output power, thereby achieving effective regulation of the power system frequency. This method not only improves the frequency regulation effect of the energy storage system, but also ensures the effectiveness and sustainability of the energy storage system, and has important application value.

[0146] In order to verify the feasibility and effectiveness of the hybrid energy storage adaptive VIR and VDR coordinated control method proposed in this invention, a regional interconnected system model was established, and specific load disturbance experimental conditions were set in the system:

[0147] 1. Experimental Setup

[0148] 1. System model:

[0149] A primary frequency regulation model of a regional power system with energy storage was constructed, including a primary frequency regulation model of conventional thermal power units and a general control model of primary frequency regulation with energy storage.

[0150] When selecting thermal power units with larger capacity as conventional frequency regulation units, the dynamic characteristics of their speed governors and reheat turbines are mainly considered.

[0151] 2. Load disturbance:

[0152] When the system was running for 2 seconds, a 5MW step load disturbance was set to simulate the sudden load change in the actual power grid.

[0153] 3. Energy storage configuration:

[0154] The method of the present invention adopts lithium batteries as energy type energy storage and super capacitors as power type energy storage, which respond to VDR and VIR control signals respectively.

[0155] 4. Comparison method:

[0156] No energy storage: The system relies solely on conventional thermal power units for frequency regulation.

[0157] Single battery control method: only lithium batteries are used to participate in VIR and VDR control at the same time.

[0158] 2. The experimental results are as follows:

[0159] 1. System frequency deviation ( Figure 2 ):

[0160] The absolute value of the maximum frequency deviation under the method of the present invention is the smallest, showing better frequency stability.

[0161] The single-lithium method is second best, but still better than no energy storage.

[0162] Without energy storage, the system frequency deviation is the largest and the stability is the worst.

[0163] 2. Output power of thermal power units ( Figure 3 ):

[0164] Under the method of the present invention, due to the rapid response of energy storage, the primary frequency regulation power demand of the thermal power unit is significantly reduced, which helps to extend the life of the thermal power unit and improve the overall economy.

[0165] In the case of single lithium method and no energy storage, thermal power units need to bear greater frequency regulation power.

[0166] 3. Hybrid energy storage output power ( Figure 4 ):

[0167] When a load disturbance occurs, the supercapacitor responds quickly to the VIR signal and suppresses frequency drop with high power output.

[0168] The lithium battery responds to the VDR signal for a long time and provides stable power support.

[0169] In contrast, the single-lithium approach has difficulty in effectively responding to the superimposed power commands of VIR and VDR simultaneously due to power limitations.

[0170] 4. Hybrid energy storage SOC ( Figure 5 ):

[0171] After the supercapacitor responds quickly at the initial stage of load disturbance, it exits operation in time to avoid excessive consumption of SOC.

[0172] The lithium battery maintains a stable SOC level throughout the frequency modulation cycle, providing support for long-term frequency modulation.

[0173] 3. Cause Analysis

[0174] 1. Rapid response characteristics of energy storage:

[0175] When the frequency drops, the energy storage system quickly demonstrates its rapid response characteristics and quickly makes up for the system's active power shortage by participating in VIR and VDR control, effectively suppressing the frequency drop.

[0176] 2. Hybrid energy storage has complementary advantages:

[0177] The supercapacitor responds to the VIR signal in a short time with high power, quickly suppressing the initial frequency change rate.

[0178] The high energy of lithium batteries can respond to VDR signals for a long time and improve the system steady-state frequency deviation.

[0179] This complementary energy storage configuration makes the frequency regulation effect more significant.

[0180] 3. Limitations of single lithium method:

[0181] Due to the power amplitude limitation of the lithium battery, it is impossible to effectively respond to the superimposed power instructions of VIR and VDR at the same time, resulting in limited frequency modulation effect.

[0182] like Figure 2 for Figure 3 It can be seen that, by comparing the system frequency deviation and the power curve of the thermal power unit, the absolute value of the maximum frequency deviation under the method of the present invention is the smallest, followed by the single-lithium method, and the worst is the method without energy storage; for the steady-state frequency deviation, the present invention is consistent with the single-lithium method, and the worst is the method without energy storage. The reason for this is that when the frequency drops, the energy storage plays its fast response characteristics, and the VIR and VDR participating in the system quickly make up for the active power shortage of the system and thus suppress the frequency drop. Therefore, the frequency regulation effect is better than that without energy storage. At the same time, the improvement of the frequency regulation effect will directly reduce the primary frequency regulation power of the thermal power unit.

[0183] Depend on Figure 4-5 It can be seen that under the single lithium method, since only lithium batteries are used to participate in VIR and VDR at the same time, it is easy to be unable to effectively respond to the power command signal after the superposition of the two due to its power amplitude limitation. However, the present invention considers using supercapacitors with high power to respond to VIR signals in a short time, and lithium batteries with high energy to respond to VDR signals in a long time. When a load disturbance occurs in the 2s system, after the energy storage primary frequency modulation dead zone set by the present invention, the high-power supercapacitor responds to the VIR signal quickly at the rated power, and the lithium battery only bears the VDR signal. When the frequency deviation reaches the lowest point, the supercapacitor exits operation, which effectively avoids the supercapacitor SOC from falling into a bad state and is also conducive to the recovery of the system frequency.

[0184] In summary, the hybrid energy storage adaptive VIR and VDR coordinated control method proposed in the present invention has demonstrated good frequency regulation effect and economy in actual system applications, and provides a new technology for primary frequency regulation of power systems.

[0185] The present application also proposes a hybrid energy storage control system based on VIR and VDR, the system comprising: a transfer function acquisition unit, a frequency modulation dynamic model construction unit, an output power and frequency deviation acquisition unit and a hybrid energy storage output power determination unit;

[0186] The transfer function acquisition unit is used to obtain the corresponding frequency modulation transfer function U based on the primary frequency modulation model of the conventional thermal power unit. huo (S); Based on the general control model of energy storage primary frequency modulation, obtain the corresponding energy storage transfer function I(s);

[0187] The FM dynamic model building unit is used to build the FM transfer function U huo (S), energy storage transfer function I(s) determines the primary frequency modulation dynamic model;

[0188] An output power and frequency deviation acquisition unit is used to determine the output power and frequency deviation corresponding to VIR control and VDR control in combination with a primary frequency modulation dynamic model;

[0189] The hybrid energy storage output power determination unit is used to determine the hybrid energy storage output power according to the output power and frequency deviation corresponding to the VIR control and the VDR control.

[0190] The present application also proposes a readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the following steps:

[0191] Based on the primary frequency regulation model of conventional thermal power units, the corresponding frequency regulation transfer function U is obtained. huo (S);

[0192] Based on the universal control model of energy storage primary frequency modulation, the corresponding energy storage transfer function I(s) is obtained;

[0193] According to the frequency modulation transfer function U huo (S), energy storage transfer function I(s) determines the primary frequency modulation dynamic model;

[0194] Combined with the primary frequency modulation dynamic model, the output power and frequency deviation corresponding to VIR control and VDR control are determined;

[0195] The output power of the hybrid energy storage is determined according to the output power and frequency deviation corresponding to the VIR control and VDR control.

[0196] The present application also proposes a computer device, including a memory and a processor, wherein the memory stores a computer program, and the computer program is executed by the processor to perform the following steps:

[0197] Based on the primary frequency regulation model of conventional thermal power units, the corresponding frequency regulation transfer function U is obtained. huo (S);

[0198] Based on the universal control model of energy storage primary frequency modulation, the corresponding energy storage transfer function I(s) is obtained;

[0199] According to the frequency modulation transfer function U huo (S), energy storage transfer function I(s) determines the primary frequency modulation dynamic model;

[0200] Combined with the primary frequency modulation dynamic model, the output power and frequency deviation corresponding to VIR control and VDR control are determined;

[0201] The output power of the hybrid energy storage is determined according to the output power and frequency deviation corresponding to the VIR control and VDR control.

[0202] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in the present application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0203] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0204] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present application. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. The above disclosure is only a preferred embodiment of the present invention, and of course it cannot be used to limit the scope of the rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope covered by the present invention.

Claims

1. A hybrid energy storage control method, characterized in that: The method comprises: Based on the primary frequency regulation model of conventional thermal power units, the corresponding frequency regulation transfer function U is obtained. huo (S); Based on the universal control model of energy storage primary frequency modulation, the corresponding energy storage transfer function I(s) is obtained; According to the frequency modulation transfer function U huo (S), the energy storage transfer function I(s) determines a primary frequency modulation dynamic model; Determine the output power and frequency deviation corresponding to VIR control and VDR control in combination with the primary frequency modulation dynamic model; The hybrid energy storage output power is determined according to the output power and frequency deviation corresponding to the VIR control and the VDR control.

2. The hybrid energy storage control method according to claim 1, characterized in that: Based on the primary frequency modulation model of conventional thermal power units, the corresponding frequency modulation transfer function U is obtained. huo (S), specifically including: Among them, R g is the time constant of the thermal power unit speed regulator; R ch is the turbine time constant; R rh is the heater time constant; E hp is the heater gain.

3. The hybrid energy storage control method according to claim 2, characterized in that: The method of obtaining the corresponding energy storage transfer function I(s) based on the energy storage primary frequency modulation general control model includes: Among them, R b,i is the energy storage time constant; The energy storage transfer function I(s) is evaluated according to the energy storage state of charge SOC: Among them, S OCk is the energy storage SOC at time t; S OC0 is the energy storage SOC at the initial moment; ΔT is a frequency modulation cycle; P b is the energy storage output power; E rate is the total capacity of the energy storage system.

4. The hybrid energy storage control method according to claim 3, characterized in that: According to the frequency modulation transfer function U huo (S), the energy storage transfer function I(s) determines a primary frequency modulation dynamic model, specifically including: ΔP huo (s)=-Δf(s)·H huo ·U huo (S) ΔP huo (s)+ΔP b (s)-ΔP L (s)=(2Q·s+D)·Δf(s) Among them, H huo The primary unit adjustment power of the thermal power unit; U huo (S) is the frequency transfer function; D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; ΔP huo (s), ΔP b (s) are the output power of thermal power units and energy storage respectively.

5. The hybrid energy storage control method according to claim 4, characterized in that: The determining the output power and frequency deviation corresponding to the VIR control and the VDR control in combination with the primary frequency modulation dynamic model specifically includes: When the energy storage battery adopts VIR control, its output power and corresponding frequency deviation are: in, is the inertia coefficient when the energy storage adopts VIR control; I(s) is the energy storage transfer function; D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; When the energy storage battery adopts VDR control, its output power and corresponding frequency deviation are: in, is the droop coefficient when energy storage adopts VDC control; I(s) is the energy storage transfer function; D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit.

6. The hybrid energy storage control method according to claim 5, characterized in that: After determining the output power and frequency deviation corresponding to the VIR control and the VDR control in combination with the primary frequency modulation dynamic model, the method further includes: obtaining the initial frequency change rate and the steady-state frequency deviation corresponding to the VIR control and the VDR control: Corresponding initial frequency change rate when using VIR control and steady-state frequency deviation for: Where D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; Δf VIR (s) is the frequency deviation corresponding to VIR control; The corresponding initial frequency change rate when VDR control is used and steady-state frequency deviation for: Among them, D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; is the steady-state frequency deviation.

7. The hybrid energy storage control method according to claim 6, characterized in that: The step of determining the hybrid energy storage output power according to the output power and frequency deviation corresponding to the VIR control and the VDR control specifically includes: The power type energy storage is determined according to the energy storage power instruction under VIR control, and the energy type energy storage is determined according to the energy storage power instruction under VDR control: Among them, ΔP b,gl (s), ΔP b,nl (s) are the output power of power type and energy type energy storage respectively; I gl (s), I nl (s) are the frequency modulation transfer functions of power type and energy type energy storage, respectively.

8. The hybrid energy storage control method according to claim 7, characterized in that: The hybrid energy storage output power is determined according to the output power and frequency deviation corresponding to the VIR control and the VDR control. After that, the method further includes obtaining the frequency control deviation: Where D is the system damping coefficient; Q is the inertia coefficient of the thermal power unit; I gl (s), I nl (s) are the frequency modulation transfer functions of power type and energy type energy storage, respectively; U huo (S) is the frequency modulation transfer function.

9. A hybrid energy storage control system based on VIR and VDR, characterized in that: The system comprises: a transfer function acquisition unit, a frequency modulation dynamic model construction unit, an output power and frequency deviation acquisition unit and a hybrid energy storage output power determination unit; The transfer function acquisition unit is used to acquire the corresponding frequency modulation transfer function U based on the primary frequency modulation model of the conventional thermal power unit. huo (S); Based on the general control model of energy storage primary frequency modulation, obtain the corresponding energy storage transfer function I(s); The frequency modulation dynamic model building unit is used to build a frequency modulation dynamic model based on the frequency modulation transfer function U huo (S), the energy storage transfer function I(s) determines a primary frequency modulation dynamic model; The output power and frequency deviation acquisition unit is used to determine the output power and frequency deviation corresponding to the VIR control and the VDR control in combination with the primary frequency modulation dynamic model; The hybrid energy storage output power determination unit is used to determine the hybrid energy storage output power according to the output power and frequency deviation corresponding to the VIR control and VDR control.

10. A readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor is caused to perform the steps of the method according to any one of claims 1 to 8.

11. A computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method according to any one of claims 1 to 8.

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