Virtual synchronous machine energy storage configuration method based on inertia demand

Abstract

The invention relates to a virtual synchronous machine energy storage configuration method based on an inertia demand, and the method comprises the steps: obtaining a frequency change rate of a target power system and a frequency safety threshold value meeting a preset lowest point condition; determining the total inertia time constant demand of the target area according to the frequency change rate and the frequency safety threshold; determining the total inertia demand of the target area according to the actual inertia of the thermal power generating unit in the target area and the actual demand of the new energy power generation facility; calculating the virtual inertia of the new energy power generation facility; and determining an energy storage configuration demand of the VSG, and generating an energy storage configuration scheme of the target power system according to the energy storage configuration demand. Therefore, the problem that the technology is difficult to popularize and apply due to the fact that only the improvement effect of the VSG technology on the system frequency stability is elaborated in the related technology and the energy storage configuration capacity and the frequency stability effect under the technology are not quantitatively analyzed and the energy storage configuration requirement cannot be determined is solved.

Description

Technical Field

[0001] The present application relates to the technical field of power system planning, and in particular to a virtual synchronous machine energy storage configuration method based on inertia demand. Background Art

[0002] In power systems, inertia refers to the system's ability to respond stably to external disturbances, especially in the face of sudden load changes or power generation equipment failures. Traditionally, this inertia mainly relies on the rotational inertia of the generator. However, with the rapid growth of renewable energy and the demand for more flexible and sustainable power systems, traditional inertia resources may not be able to meet the needs of new power systems.

[0003] Among the related technologies, the virtual synchronous generator (VSG) energy storage system, as an emerging technology, is becoming one of the important means to improve the inertia of the power system. The VSG energy storage system uses batteries and other energy storage devices to simulate the inertia characteristics of traditional generators, which can quickly respond to changes in grid frequency and improve the stability and reliability of the power system.

[0004] However, the relevant technology only explains the role of VSG technology in improving system frequency stability, and remains at the qualitative analysis stage. There is no quantitative analysis of the energy storage configuration capacity and frequency stability effect under this technology, and it is impossible to determine the configuration requirements of energy storage, which makes it difficult to promote and apply this technology, and it is in urgent need of improvement. Summary of the invention

[0005] The present application provides a virtual synchronous machine energy storage configuration method based on inertia demand, in order to solve the problem that the related technology only describes the effect of VSG technology on improving system frequency stability, and stays at the qualitative analysis, but does not have a quantitative analysis of the energy storage configuration capacity and frequency stability effect under this technology, and cannot determine the configuration requirements of energy storage, which makes the technology difficult to promote and apply.

[0006] The first aspect of the present application provides a virtual synchronous machine energy storage configuration method based on inertia demand, comprising the following steps: obtaining the frequency change rate of the target power system and a frequency safety threshold that meets a preset minimum point condition; determining the total inertia time constant demand of the target area according to the frequency change rate and the frequency safety threshold; based on the total inertia time constant demand, determining the total inertia demand of the target area according to the actual inertia of the thermal power units in the target area and the actual demand of the new energy power generation facilities; based on the total inertia demand of the target area, calculating the virtual inertia of the new energy power generation facilities; based on the virtual inertia and the control target of the virtual synchronous machine VSG, determining the energy storage configuration demand of the VSG, and generating an energy storage configuration plan for the target power system according to the energy storage configuration demand.

[0007] Optionally, in one embodiment of the present application, determining the total inertia time constant requirement for the target area based on the frequency change rate and the preset frequency safety threshold includes: determining the inertia time constant that meets the preset frequency requirement based on the frequency change rate and the frequency point that meets the preset minimum condition; based on the frequency change rate constraint and the frequency constraint that meets the preset minimum point condition, determining the total inertia time constant requirement based on the frequency change rate threshold and the frequency point threshold that meets the preset minimum condition.

[0008] Optionally, in one embodiment of the present application, the relationship between the frequency change rate and the inertia time constant is expressed as:

[0009]

[0010] Among them, △P max is the missing value, f N is the rated frequency, H sys is a constant;

[0011] The relationship between the frequency point that meets the preset minimum condition and the inertia time constant is expressed as:

[0012]

[0013] Among them, f N is the rated frequency, t db is the primary frequency modulation dead time, f db FM dead zone, R sys is the system equivalent primary adjustment coefficient, △P max is the missing value, D is the system equivalent damping coefficient, t nadir is the time when the frequency reaches the lowest point, H sys is the inertia time constant;

[0014] The total inertia time constant requirement is calculated as:

[0015]

[0016]

[0017] H min =max{H min,RoCoF ,H min,nadir},

[0018] Among them, △P max is the shortfall value, f N is the rated frequency, t db is the primary frequency modulation dead time, R sys is the equivalent primary adjustment coefficient of the system, △Pmax is the shortage value, and D is the equivalent damping coefficient of the system.

[0019] Optionally, in one embodiment of the present application, the total inertia demand of the target area is calculated as follows when the total inertia demand is a nominal value:

[0020]

[0021] Among them, P m is the mechanical power, ω0 is the rated angular frequency, P e is the electromagnetic power, D is the damping coefficient; ω is the generator angular frequency.

[0022] The total inertia demand of the target area is calculated as per unit value:

[0023]

[0024] Among them, T J is the time required to apply rated torque to drag the generator from static to rated speed, D is the damping coefficient, is the per-unit value of mechanical power, dω * is the per-unit value of the derivative of the generator angular frequency, is the per-unit value of mechanical power, ω * is the per-unit value of the generator angular frequency, Δω * It is the per-unit value of the difference between the generator angular frequency and the rated angular frequency.

[0025] Optionally, in one embodiment of the present application, the expression of the simulated rotor motion equation for determining the energy storage configuration requirement of the VSG based on the virtual inertia and the control target of the virtual synchronous machine VSG is:

[0026]

[0027] Among them, J vsg is the virtual inertia time constant, P m is the mechanical power, P e is the electromagnetic power, δ is the power angle, D is the damping coefficient, ω g is the grid angular frequency, ω0 is the rated angular frequency, ω is the VSG angular frequency;

[0028] The expression of the power of the energy storage that meets the preset maximum demand condition is:

[0029]

[0030] Among them, P e is the electromagnetic power, t pmax is the moment of peak energy storage power;

[0031] The expression of the energy storage capacity requirement is:

[0032] E VSG =E min -E G ,

[0033] Among them, E min is the required inertia of the target area to meet the preset minimum conditions, E G The inertia of the thermal power unit comes from the rotor kinetic energy.

[0034] Optionally, in one embodiment of the present application, in the calculation of the virtual inertia of the new energy power generation facility based on the total inertia demand of the target area, when the new energy power generation facility performs energy storage equivalent replacement, the expression for energy storage capacity configuration is:

[0035] E VSG =E G ,

[0036] Among them, E G The inertia of the thermal power unit comes from the rotor kinetic energy.

[0037] The second aspect of the present application provides a virtual synchronous machine energy storage configuration device based on inertia demand, including: an acquisition module, used to acquire the frequency change rate of the target power system and the frequency safety threshold that meets the preset minimum point condition; a first determination module, used to determine the total inertia time constant demand of the target area according to the frequency change rate and the frequency safety threshold; a second determination module, used to determine the total inertia demand of the target area based on the total inertia time constant demand, according to the actual inertia of the thermal power units in the target area and the actual demand of the new energy power generation facilities; a calculation module, used to calculate the virtual inertia of the new energy power generation facilities based on the total inertia demand of the target area; an energy storage configuration module, used to determine the energy storage configuration demand of the VSG based on the virtual inertia and the control target of the virtual synchronous machine VSG, and generate an energy storage configuration plan for the target power system according to the energy storage configuration demand.

[0038] Optionally, in one embodiment of the present application, the first determination module includes: a first determination unit, used to determine the inertia time constant that meets the preset frequency requirement based on the frequency change rate and the frequency point that meets the preset minimum condition; a second determination unit, used to determine the requirement for the total inertia time constant based on the frequency change rate constraint and the frequency constraint that meets the preset minimum point condition, according to the threshold of the frequency change rate and the threshold of the frequency point that meets the preset minimum condition.

[0039] Optionally, in one embodiment of the present application, the relationship between the frequency change rate and the inertia time constant is expressed as:

[0040]

[0041] Among them, △P max is the missing value, f N is the rated frequency, H sys is a constant;

[0042] The relationship between the frequency point that meets the preset minimum condition and the inertia time constant is expressed as:

[0043]

[0044]

[0045] Among them, f N is the rated frequency, t db is the primary frequency modulation dead time, f db FM dead zone, R sys is the system equivalent primary adjustment coefficient, △P max is the missing value, D is the system equivalent damping coefficient, t nadir is the time when the frequency reaches the lowest point, H sys is the inertia time constant;

[0046] The total inertia time constant requirement is calculated as:

[0047]

[0048] H min =max{H min,RoCoF ,H min,nadir},

[0049] Among them, △P max is the shortfall value, f N is the rated frequency, t db is the primary frequency modulation dead time, R sys is the equivalent primary adjustment coefficient of the system, △P max is the shortage value, and D is the equivalent damping coefficient of the system.

[0050] Optionally, in one embodiment of the present application, the total inertia demand of the target area is calculated as follows when the total inertia demand is a nominal value:

[0051]

[0052] Among them, P m is the mechanical power, ω0 is the rated angular frequency, P e is the electromagnetic power, D is the damping coefficient, and ω is the generator angular frequency;

[0053] The total inertia demand of the target area is calculated as per unit value:

[0054]

[0055] Among them, T J is the time required to apply rated torque to drag the generator from static to rated speed, D is the damping coefficient, is the per unit value of mechanical power, dω * is the per-unit value of the derivative of the generator angular frequency, is the per-unit value of mechanical power, ω * is the per-unit value of the generator angular frequency, Δω * It is the per-unit value of the difference between the generator angular frequency and the rated angular frequency.

[0056] Optionally, in one embodiment of the present application, the expression of the simulated rotor motion equation for determining the energy storage configuration requirement of the virtual synchronous machine VSG according to the control target of the VSG is:

[0057]

[0058] Among them, J vsg is the virtual inertia time constant, P m is the mechanical power, P e is the electromagnetic power, δ is the power angle, D is the damping coefficient, ω g is the grid angular frequency, ω0 is the rated angular frequency, ω is the VSG angular frequency;

[0059] The expression of the power of the energy storage that meets the preset maximum demand condition is:

[0060]

[0061] Among them, P e is the electromagnetic power, t pmax is the moment of peak energy storage power;

[0062] The expression of the energy storage capacity requirement is:

[0063] E VSG =E min -E G ,

[0064] Among them, E min is the required inertia of the target area to meet the preset minimum conditions, E G The inertia of the thermal power unit comes from the rotor kinetic energy.

[0065] Optionally, in one embodiment of the present application, in the calculation of the virtual inertia of the new energy power generation facility based on the total inertia demand of the target area, when the new energy power generation facility performs energy storage equivalent replacement, the expression for energy storage capacity configuration is:

[0066] E VSG =E G ,

[0067] Among them, E G The inertia of the thermal power unit comes from the rotor kinetic energy.

[0068] A third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement a virtual synchronous machine energy storage configuration method based on inertia demand as described in the above embodiment.

[0069] A fourth aspect of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, which, when executed by a processor, implements the above-mentioned virtual synchronous machine energy storage configuration method based on inertia demand.

[0070] A fifth aspect of the present application provides a computer program product, which stores a computer program that, when executed by a processor, implements the above-mentioned virtual synchronous machine energy storage configuration method based on inertia requirements.

[0071] The embodiments of the present application can adopt the method of mechanism analysis and deduction to specifically give the configuration requirements of energy storage, which will provide more accurate and reliable decision-making basis for power system operators and help improve the stability and reliability of the power system. At the same time, it also helps to reduce the operating costs of the system, reduce dependence on traditional power generation resources, and promote the development of the power system in a more flexible and sustainable direction. Thus, it solves the problem that the relevant technology only describes the role of VSG technology in improving the frequency stability of the system, and stays at the qualitative analysis, but there is no quantitative analysis of the energy storage configuration capacity and frequency stability effect under this technology, and it is impossible to determine the configuration requirements of energy storage, which makes it difficult to promote and apply this technology.

[0072] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0074] Figure 1A flowchart of a virtual synchronous machine energy storage configuration method based on inertia demand provided according to an embodiment of the present application;

[0075] Figure 2 A flow chart of a VSG energy storage configuration method based on inertia requirements according to an embodiment of the present application;

[0076] Figure 3 Schematic diagram of system frequency response curves in three scenarios according to an embodiment of the present application;

[0077] Figure 4 A schematic diagram of the structure of a virtual synchronous machine energy storage configuration device based on inertia demand provided according to an embodiment of the present application;

[0078] Figure 5 It is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0079] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0080] The following describes a virtual synchronous machine energy storage configuration method based on inertia demand in an embodiment of the present application with reference to the accompanying drawings. In view of the related technologies mentioned in the above background technology, only the VSG technology is described to improve the system frequency stability, and it stays at the qualitative analysis. However, there is no quantitative analysis of the energy storage configuration capacity and frequency stability effect under this technology, and it is impossible to determine the configuration requirements of energy storage, which leads to the problem that this technology is difficult to promote and apply. This application provides a virtual synchronous machine energy storage configuration method based on inertia demand. In this method, by comprehensively considering the characteristics of the power system, the penetration rate of renewable energy and other factors, the VSG energy storage configuration scheme is quantitatively analyzed, which has important theoretical and practical significance for improving the inertia response capability of the power system under the background of large-scale grid connection of new energy in the power system, and provides a configuration idea for the energy storage planning of new energy grid connection. Therefore, it solves the problem that the related technology only describes the improvement effect of VSG technology on system frequency stability, and stays at the qualitative analysis. However, there is no quantitative analysis of the energy storage configuration capacity and frequency stability effect under this technology, and it is impossible to determine the configuration requirements of energy storage, which leads to the problem that this technology is difficult to promote and apply.

[0081] Specifically, Figure 1 A schematic flow chart of a virtual synchronous machine energy storage configuration method based on inertia requirements provided in an embodiment of the present application.

[0082] like Figure 1As shown, the virtual synchronous machine energy storage configuration method based on inertia demand includes the following steps:

[0083] In step S101, the frequency change rate of the target power system and a frequency safety threshold that meets a preset minimum point condition are obtained.

[0084] It can be understood that the frequency safety threshold of the preset minimum point condition in the embodiment of the present application can be a frequency minimum point safety threshold.

[0085] In the actual implementation process, the embodiment of the present application can obtain the system frequency change rate (RoCoF) and the lowest frequency point (f nadir ) safety threshold, thereby providing support for the subsequent determination of the total inertia time constant requirement.

[0086] It should be noted that the preset minimum point condition can be set by those skilled in the art according to actual conditions and is not specifically limited here.

[0087] In step S102 , the total inertia time constant requirement of the target area is determined according to the frequency change rate and the frequency safety threshold.

[0088] During the actual implementation process, the embodiment of the present application can determine the total inertia time constant requirement of the target area based on the frequency change rate and the frequency safety threshold, provide support for the subsequent determination of energy storage configuration requirements, and improve the stability and reliability of the power system.

[0089] Optionally, in one embodiment of the present application, the total inertia time constant requirement of the target area is determined based on the frequency change rate and a preset frequency safety threshold, including: determining the inertia time constant that meets the preset frequency requirement based on the frequency change rate and the frequency point that meets the preset minimum condition; based on the frequency change rate constraint and the frequency constraint that meets the preset minimum point condition, determining the total inertia time constant requirement based on the frequency change rate threshold and the frequency point threshold that meets the preset minimum condition.

[0090] It can be understood that the frequency point of the preset minimum condition in the embodiment of the present application can be the lowest frequency point.

[0091] As a possible implementation method, the embodiment of the present application can set frequency safety indicators, such as the frequency change rate RoCoF, the frequency minimum point f nadir , determine the inertia time constant that meets the frequency requirements, based on the frequency change rate constraint and the frequency minimum point constraint, and determine the total inertia time constant requirement according to the frequency change rate threshold and the frequency minimum point threshold.

[0092] In one embodiment of the present application, the relationship between the frequency change rate and the inertia time constant is expressed as follows:

[0093]

[0094] Among them, △P max is the missing value, f N is the rated frequency, H sys is a constant;

[0095] The relationship between the lowest frequency point and the inertia time constant is expressed as:

[0096]

[0097]

[0098] Among them, f N is the rated frequency, t db is the primary frequency modulation dead time, f db FM dead zone, R sys is the system equivalent primary adjustment coefficient, △P max is the missing value, D is the system equivalent damping coefficient, t nadir is the time when the frequency reaches the lowest point, H sys is the inertia time constant;

[0099] Therefore, the RoCoF threshold is set, and the corresponding total inertia time constant requirement is calculated as follows:

[0100]

[0101] Set the lowest frequency f nadir Threshold, corresponding to H sys The requirements are:

[0102]

[0103] Among them, △P max is the missing value, f N is the rated frequency, t db is the primary frequency modulation dead time, R sys is the system equivalent primary adjustment coefficient, △P max is the missing value, and D is the equivalent damping coefficient of the system.

[0104] The embodiment of the present application can comprehensively consider the frequency change rate constraint and the frequency minimum point constraint, and the minimum inertia constant of the system can be obtained as:

[0105] H min =max{H min,RoCoF ,H min,nadir}, (7)

[0106] It should be noted that the preset minimum condition, the preset frequency requirement and the preset minimum point condition can be set by those skilled in the art according to actual conditions and are not specifically limited here.

[0107] In step S103, based on the total inertia time constant requirement, the total inertia requirement of the target area is determined according to the actual inertia of the thermal power units in the target area and the actual requirements of the new energy power generation facilities.

[0108] It can be understood that in the embodiment of the present application, the total inertia requirement of the region can be determined according to the frequency safety threshold.

[0109] In the actual implementation process, the embodiment of the present application can first clarify the inertia time constant and the inertia conversion method, and then perform the calculation.

[0110] In one embodiment of the present application, the system frequency response equation is similar to the rotor motion equation:

[0111] The calculation formula for the total inertia demand of the target area with nominal value is:

[0112]

[0113] Among them, P m is the mechanical power, ω0 is the rated angular frequency, P e is the electromagnetic power, D is the damping coefficient, and ω is the generator angular frequency;

[0114] The total inertia requirement of the target area is calculated as per unit:

[0115]

[0116] in, T J It is the time required to apply rated torque to drag the generator from static to rated speed, D is the damping coefficient, is the per-unit value of mechanical power, dω * is the per-unit value of the derivative of the generator angular frequency, is the per-unit value of mechanical power, ω * is the per-unit value of the generator angular frequency, Δω * It is the per-unit value of the difference between the generator angular frequency and the rated angular frequency.

[0117] Where, T J Its system inertia constant H sys The relationship is

[0118] T J =2H sys , (10)

[0119] In the absence of virtual inertia, the regional inertia is all provided by the thermal power units, and the inertia of the thermal power units comes from the rotor kinetic energy:

[0120]

[0121] By analogy, when the regional inertia can be provided by thermal power units and new energy storage, the minimum required inertia expression of the region is:

[0122] E min =H min S sys , (12)

[0123] In step S104 , the virtual inertia of the new energy power generation facility is calculated based on the total inertia demand of the target area.

[0124] In the actual implementation process, the embodiment of the present application can calculate the virtual inertia provided by the new energy power generation facility. The source of inertia consists of two parts, one is the rotor inertia of the traditional thermal power unit, and the other is the virtual inertia provided by the new energy through energy storage. When the new energy storage is equivalent to replacing fire, the expression of the energy storage capacity configuration is:

[0125] E VSG =E G , (13)

[0126] Among them, E G The inertia of the thermal power unit comes from the rotor kinetic energy.

[0127] Energy storage capacity configuration to meet regional inertia requirements:

[0128] E VSG =E min -E G (14)

[0129] In step S105 , based on the virtual inertia and the control target of the virtual synchronous machine VSG, the energy storage configuration requirement of the VSG is determined, and an energy storage configuration scheme of the target power system is generated according to the energy storage configuration requirement.

[0130] In the actual implementation process, the embodiment of the present application can determine the energy storage configuration requirements of the VSG based on the virtual inertia and the control target of the VSG, and generate the energy storage configuration scheme of the target power system according to the energy storage configuration requirements, thereby ensuring that the calculated energy storage configuration amount can maximize the use of available energy storage resources while meeting the power system's demand for inertia. This can avoid over-configuration or under-configuration of the energy storage system, thereby optimizing the utilization efficiency of resources.

[0131] Furthermore, the embodiments of the present application can optimize resource utilization: the calculated energy storage configuration can maximize the use of available energy storage resources while meeting the power system's demand for inertia. This can avoid over-configuration or under-configuration of the energy storage system, thereby optimizing resource utilization efficiency.

[0132] The embodiment of the present application can ensure system stability: the energy storage configuration calculated based on the inertia requirement can ensure that the system can maintain a stable frequency when facing load changes or external disturbances. By meeting the system's inertia requirements, the anti-interference ability of the power system can be improved, the risk of frequency drop can be reduced, and the stable operation of the system can be guaranteed.

[0133] The embodiments of the present application can reduce costs and improve efficiency: the calculated optimal energy storage configuration can reduce system operating costs. A properly configured energy storage system can reduce dependence on traditional power generation resources, reduce fuel costs and emissions, and improve the economic benefits and energy efficiency of system operation.

[0134] The embodiments of the present application can promote the integration of renewable energy: the energy storage configuration calculated based on the inertia demand can better promote the large-scale integration of renewable energy. By improving the flexibility and response speed of the power system, the energy storage system can more effectively balance and regulate the volatility of renewable energy and achieve reliable acceptance and utilization of renewable energy.

[0135] In one embodiment of the present application, based on the virtual inertia and the control target of the virtual synchronous machine VSG, the expression of the simulated rotor motion equation for determining the energy storage configuration requirement of the VSG is:

[0136]

[0137] Among them, J vsg It is the virtual inertia time constant. It is different from thermal power units and can be set flexibly according to needs. vsg The corresponding maximum power and capacity requirements of energy storage are different; P m is the mechanical power (output of new energy units), P e is the electromagnetic power (energy storage output), δ is the power angle, D is the damping coefficient, ω g is the grid angular frequency, ω0 is the rated angular frequency, ω is the VSG angular frequency, and considering that VSG has both inertial response and primary frequency regulation functions, then:

[0138] P m =P ref +K f (ω0-ω g ) (16)

[0139] Perform Laplace transform and convert it into s-domain equation:

[0140]

[0141] again

[0142] Among them, S E represents synchronous power, S E =EU g sinδ / (S n Z), E is the inverter port voltage; U g is the grid voltage; S n is the rated capacity of VSG; Z is the line impedance, α is the impedance angle, δ is the power angle, and the impedance angle is approximately π / 2.

[0143] Assuming that the power fluctuation caused by frequency fluctuation is entirely borne by energy storage, the s-domain expression of energy storage power fluctuation with frequency is obtained as follows:

[0144]

[0145] △ω g (s) is a step signal change. The above s-domain expression can be converted into a time-domain expression through inverse Laplace transform:

[0146]

[0147] The expression of the power required for energy storage to meet the preset maximum demand condition is:

[0148]

[0149] Among them, P e is the electromagnetic power, t pmax is the moment of peak energy storage power;

[0150] The expression of energy storage capacity requirement is:

[0151] E VSG =E min -E G ,(twenty one)

[0152] Among them, E min The required inertia of the target area to meet the preset minimum conditions, E G The inertia of the thermal power unit comes from the rotor kinetic energy.

[0153] It should be noted that the representation in step 4 is the maximum inertia level of the region, that is, the situation where the angular velocity of the synchronous machine drops to 0. There will be a certain waste of energy storage capacity configured according to this representation method. In actual situations, the frequency will not drop to 0. It is necessary to convert it from the perspective of the energy that can actually be released by the synchronous unit, and change it to:

[0154]

[0155] Specifically, it can be combined Figure 2 As shown, the working principle of a virtual synchronous machine energy storage configuration method based on inertia demand in an embodiment of the present application is described in detail with a specific embodiment.

[0156] like Figure 2 As shown, the embodiment of the present application may include the following steps:

[0157] Step S201: Determine the system frequency change rate (RoCoF) and the frequency minimum point (fnadir) safety thresholds.

[0158] Step S202: Determine the regional total inertia time constant requirement according to the frequency safety threshold.

[0159] Step S203: Determine the total inertia requirement of the region.

[0160] Step S204: Calculate the virtual inertia that the new energy needs to provide.

[0161] Step S205: Determine energy storage configuration requirements using virtual synchronous machine technology (VSG) control.

[0162] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0163] Example:

[0164] The simulation verification is carried out on a three-machine nine-node system. The rated capacity of G1 is 247.5MVA, the rated capacity of G2 is 192MVA, the rated capacity of G3 is 128MVA, the load is 405MW, and the power shortage is 22% (89.1MW). The maximum RoCoF allowed by the system is required to be 1Hz / s, f nadir =49.2Hz. Set the following three scenes.

[0165] Scenario 1: G1, G2, and G3 are all thermal power units, with a total capacity of 567.5MVA. The inertia constants are 23.64s, 6.4s, and 3.01s, respectively, and the differential coefficient of the primary frequency regulation system is 0.05.

[0166] Scenario 2: G2 is replaced by a PV station with a rated capacity of 308MW, and each 1MW PV array is equipped with 0.117MW / 1.586MWs of energy storage, using VSG control.

[0167] Scenario 3: G2 is replaced by a PV station with a rated capacity of 308MW, and each 1MW PV array is equipped with 0.157MW / 1.671MWs of energy storage, using VSG control.

[0168] Step 1: Determine the system frequency change rate (RoCoF), the lowest frequency point (f nadir ) Safety threshold;

[0169] Set RoCoF to 1 Hz / s, f nadir It is 49.2Hz.

[0170] Step 2: Determine the regional total inertia time constant requirement based on the frequency safety threshold;

[0171]

[0172] Solve for H min,nadir =15.77.

[0173]

[0174] Take the maximum value of the two min It is 15.77.

[0175] Step 3: Determine the total inertia demand of the region;

[0176] E min =H min,RoCoF S sys =15.77×567.5=8949.5MWs.

[0177] Step 4: Calculate the virtual inertia that the new energy needs to provide;

[0178] G2 thermal power unit provides inertia:

[0179]

[0180] In scenario 2, the virtual inertia that new energy needs to provide to replace G2 is:

[0181] E VSG =E G =1228.8MWs.

[0182] In scenario 3, the virtual inertia required to replace G2 with new energy and meet the inertia requirements is:

[0183] E VSG =E min -E G =8949.5-23.64×247.5-3.01×128=2713.3MWs.

[0184] Step 5: Determine the energy storage configuration requirements using virtual synchronous machine technology (VSG) control;

[0185] Scenario 2: Energy storage configuration plan for replacing fire with new energy:

[0186]

[0187] Unit energy storage capacity requirements:

[0188] The required VSG energy storage capacity for a 1MW PV array is 0.127MWs. Find J vsg , re-submit to get the unit energy storage power demand:

[0189]

[0190] Scenario 3: Energy storage capacity configuration scheme for replacing fire and meeting inertia requirements:

[0191]

[0192] Unit energy storage capacity requirements:

[0193] The required VSG energy storage capacity for a 1MW PV array is 0.280MWs. Find J vsg , re-submit to get the unit energy storage power demand:

[0194]

[0195] If the frequency regulation time is considered to be 30s, the energy storage configuration schemes under the three scenarios and the regional maximum inertia levels represented are shown in Table 1:

[0196] Table 1 Energy storage configuration schemes and maximum inertia levels under three scenarios

[0197]

[0198] According to the newly added new energy installed capacity, scenario 2 requires 11.7% energy storage, and scenario 3 requires 15.7% energy storage. The calculated results also meet the engineering requirements of configuring 10% to 20% energy storage for newly added new energy bases. Figure 3 The system frequency response curves under different energy storage configuration schemes are further explained. By comparing the results of the three scenarios, it can be found that the RoCoF and f nadir The similarity of the index levels indicates that the VSG energy storage capacity is set correctly. From the perspective of inertia support, it can achieve the same effect as a thermal power unit, and the power response speed of VSG technology is faster. nadir The indicator level does not meet the safety threshold requirements, and the frequency response curve in scenario 3 RoCoF = 0.7673 Hz / s, f nadir=49.2Hz, which meets the frequency safety threshold requirement. This shows that the energy storage configuration scheme in scenario 3 can meet the inertia requirement for frequency safety and provides richer and more flexible inertia than the scenario with only thermal power units.

[0199] This example confirms the effectiveness and feasibility of the VSG energy storage configuration method based on inertia demand proposed in the present invention. The method adopts the method of mechanism analysis and derivation to specifically give the configuration requirements of energy storage. The calculation results show that this method helps to improve the transient frequency stability of the power system.

[0200] According to the virtual synchronous machine energy storage configuration method based on inertia demand proposed in the embodiment of the present application, it is possible to optimize resource utilization, ensure system stability, reduce costs, and improve efficiency, while promoting the integration of renewable energy, and driving the power system to develop in a more flexible and sustainable direction, providing a configuration idea for energy storage planning for new energy grid connection. Thus, it solves the problem that the relevant technology only describes the role of VSG technology in improving system frequency stability, and stays at the qualitative analysis, but does not quantitatively analyze the energy storage configuration capacity and frequency stability effect under this technology, and cannot determine the configuration requirements of energy storage, which makes it difficult to promote and apply this technology.

[0201] Next, a virtual synchronous machine energy storage configuration device based on inertia demand proposed in an embodiment of the present application is described with reference to the accompanying drawings.

[0202] Figure 4 It is a structural schematic diagram of a virtual synchronous machine energy storage configuration device based on inertia demand in an embodiment of the present application.

[0203] like Figure 4 As shown, the virtual synchronous machine energy storage configuration device 10 based on inertia demand includes: an acquisition module 100 , a first determination module 200 , a second determination module 300 , a calculation module 400 and an energy storage configuration module 500 .

[0204] Specifically, the acquisition module 100 is used to acquire the frequency change rate of the target power system and a frequency safety threshold that meets a preset minimum point condition.

[0205] The first determination module 200 is used to determine the total inertia time constant requirement of the target area according to the frequency change rate and the frequency safety threshold.

[0206] The second determination module 300 is used to determine the total inertia demand of the target area based on the total inertia time constant demand and according to the actual inertia of the thermal power units in the target area and the actual demand of the new energy power generation facilities.

[0207] The calculation module 400 is used to calculate the virtual inertia of the new energy power generation facilities based on the total inertia demand of the target area.

[0208] The energy storage configuration module 500 is used to determine the energy storage configuration requirements of the VSG based on the virtual inertia and the control target of the virtual synchronous machine, and generate an energy storage configuration solution for the target power system according to the energy storage configuration requirements.

[0209] Optionally, in one embodiment of the present application, the first determination module 200 includes: a first determination unit and a second determination unit.

[0210] The first determination unit is used to determine the inertia time constant that meets the preset frequency requirement according to the frequency change rate and the frequency point that meets the preset minimum condition.

[0211] The second determining unit is used to determine the requirement of the total inertia time constant according to the frequency change rate constraint and the frequency constraint that meets the preset minimum point condition, and the threshold of the frequency change rate and the threshold of the frequency point that meets the preset minimum condition.

[0212] Optionally, in one embodiment of the present application, the relationship between the frequency change rate and the inertia time constant is expressed as:

[0213]

[0214] Among them, △P max is the missing value, f N is the rated frequency, H sys is a constant;

[0215] The relationship between the frequency point that meets the preset minimum condition and the inertia time constant is expressed as:

[0216]

[0217] Among them, f N is the rated frequency, t db is the primary frequency modulation dead time, f db FM dead zone, R sys is the system equivalent primary adjustment coefficient, △P max is the missing value, D is the system equivalent damping coefficient, t nadir is the time when the frequency reaches the lowest point, H sys is the inertia time constant;

[0218] The total inertia time constant requirement is calculated as:

[0219]

[0220] H min =max{H min,RoCoF ,H min,nadir},

[0221] Among them, △P maxis the missing value, f N is the rated frequency, t db is the primary frequency modulation dead time, R sys is the system equivalent primary adjustment coefficient, △P max is the missing value, and D is the equivalent damping coefficient of the system.

[0222] Optionally, in one embodiment of the present application, the total inertia demand of the target area is calculated as follows when the total inertia demand is a nominal value:

[0223]

[0224] Among them, P m is the mechanical power, ω0 is the rated angular frequency, P e is the electromagnetic power, D is the damping coefficient, and ω is the generator angular frequency;

[0225] The total inertia requirement of the target area is calculated as per unit:

[0226]

[0227] Among them, T J It is the time required to apply rated torque to drag the generator from static to rated speed, D is the damping coefficient, is the per-unit value of mechanical power, dω * is the per-unit value of the derivative of the generator angular frequency, is the per-unit value of mechanical power, ω * is the per-unit value of the generator angular frequency, Δω * It is the per-unit value of the difference between the generator angular frequency and the rated angular frequency.

[0228] Optionally, in one embodiment of the present application, based on the virtual inertia and the control target of the virtual synchronous machine VSG, the expression of the simulated rotor motion equation for determining the energy storage configuration requirement of the VSG is:

[0229]

[0230] Among them, J vsg is the virtual inertia time constant, P m is the mechanical power, P e is the electromagnetic power, δ is the power angle, D is the damping coefficient, ω g is the grid angular frequency, ω0 is the rated angular frequency;

[0231] The expression of the power required for energy storage to meet the preset maximum demand condition is:

[0232]

[0233] Among them, P e is the electromagnetic power, tpmax is the moment of peak energy storage power;

[0234] The expression of energy storage capacity requirement is:

[0235] E VSG =E min -E G ,

[0236] Among them, E min The required inertia of the target area to meet the preset minimum conditions, E G The inertia of the thermal power unit comes from the rotor kinetic energy.

[0237] Optionally, in one embodiment of the present application, based on the total inertia demand of the target area, in calculating the virtual inertia of the new energy power generation facility, when the new energy power generation facility performs storage equivalent replacement of fire, the expression for energy storage capacity configuration is:

[0238] E VSG =E G ,

[0239] Among them, E G The inertia of the thermal power unit comes from the rotor kinetic energy.

[0240] It should be noted that the above explanation of the embodiment of a virtual synchronous machine energy storage configuration method based on inertia demand is also applicable to a virtual synchronous machine energy storage configuration device based on inertia demand in this embodiment, which will not be repeated here.

[0241] According to the inertia demand-based virtual synchronous machine energy storage configuration device proposed in the embodiment of the present application, a mechanism analysis and derivation method is used to specifically give the configuration requirements of energy storage, which will provide power system operators with more accurate and reliable decision-making basis, and help improve the stability and reliability of the power system. At the same time, it also helps to reduce the operating costs of the system, reduce dependence on traditional power generation resources, and promote the development of the power system in a more flexible and sustainable direction. Thus, it solves the problem that the relevant technology only describes the role of VSG technology in improving the frequency stability of the system, and stays at the qualitative analysis, but there is no quantitative analysis of the energy storage configuration capacity and frequency stability effect under this technology, and it is impossible to determine the configuration requirements of energy storage, which makes it difficult to promote and apply this technology.

[0242] Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0243] A memory 501 , a processor 502 , and a computer program stored in the memory 501 and executable on the processor 502 .

[0244] When the processor 502 executes the program, a virtual synchronous machine energy storage configuration method based on inertia requirement provided in the above embodiment is implemented.

[0245] Furthermore, the electronic device further comprises:

[0246] The communication interface 503 is used for communication between the memory 501 and the processor 502 .

[0247] The memory 501 is used to store computer programs that can be executed on the processor 502 .

[0248] The memory 501 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0249] If the memory 501, the processor 502 and the communication interface 503 are implemented independently, the communication interface 503, the memory 501 and the processor 502 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 5 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0250] Optionally, in a specific implementation, if the memory 501, the processor 502 and the communication interface 503 are integrated on a chip, the memory 501, the processor 502 and the communication interface 503 can communicate with each other through an internal interface.

[0251] The processor 502 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0252] This embodiment further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the above-mentioned virtual synchronous machine energy storage configuration method based on inertia demand is implemented.

[0253] An embodiment of the present application further provides a computer program product on which a computer program is stored, and when the program is executed by a processor, the above-mentioned virtual synchronous machine energy storage configuration method based on inertia demand is implemented.

[0254] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0255] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0256] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0257] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or N wirings (electronic devices), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways as necessary and then storing it in a computer memory.

[0258] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0259] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0260] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0261] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A virtual synchronous machine energy storage configuration method based on inertia demand, characterized in that: The following steps are involved: Obtain the frequency change rate of the target power system and the frequency safety threshold that meets the preset minimum point condition; determining a total inertia time constant requirement for a target area according to the frequency change rate and the frequency safety threshold; Based on the total inertia time constant requirement, the total inertia requirement of the target area is determined according to the actual inertia of the thermal power units in the target area and the actual requirements of the new energy power generation facilities; Calculating the virtual inertia of the new energy power generation facility based on the total inertia demand of the target area; Based on the virtual inertia and the control target of the virtual synchronous machine VSG, the energy storage configuration requirement of the VSG is determined, and the energy storage configuration scheme of the target power system is generated according to the energy storage configuration requirement.

2. The method according to claim 1, characterized in that The determining of the total inertia time constant requirement of the target area according to the frequency change rate and the preset frequency safety threshold comprises: Determine an inertia time constant that meets a preset frequency requirement according to the frequency change rate and the frequency point that meets a preset minimum condition; Based on the frequency change rate constraint and the frequency constraint that meets the preset minimum point condition, the requirement for the total inertia time constant is determined according to the threshold of the frequency change rate and the threshold of the frequency point that meets the preset minimum condition.

3. The method according to claim 2, characterized in that The relationship between the frequency change rate and the inertia time constant is expressed as: Among them, △P max is the missing value, f N is the rated frequency, H sys is a constant; The relationship between the frequency point that meets the preset minimum condition and the inertia time constant is expressed as: Among them, f N is the rated frequency, t db is the primary frequency modulation dead time, f db FM dead zone, R sys is the system equivalent primary adjustment coefficient, △P max is the missing value, D is the system equivalent damping coefficient, t nadir is the time when the frequency reaches the lowest point, H sys is the inertia time constant; The total inertia time constant requirement is calculated as: H min =max{H min,RoCoF ,H min,nadir }, Among them, △P max is the shortfall value, f N is the rated frequency, t db is the primary frequency modulation dead time, R sys is the equivalent primary adjustment coefficient of the system, △P max is the shortage value, and D is the equivalent damping coefficient of the system.

4. The method according to claim 1, characterized in that: The calculation formula for the total inertia demand of the target area with nominal value is: Among them, P m is the mechanical power, ω0 is the rated angular frequency, P e is the electromagnetic power, D is the damping coefficient, and ω is the generator angular frequency; The total inertia demand of the target area is calculated as per unit value: Among them, T J is the time required to apply rated torque to drag the generator from static to rated speed, D is the damping coefficient, is the per unit value of mechanical power, dω * is the per-unit value of the derivative of the generator angular frequency, is the per-unit value of mechanical power, ω * is the per-unit value of the generator angular frequency, Δω * It is the per-unit value of the difference between the generator angular frequency and the rated angular frequency.

5. The method according to claim 4, characterized in that The expression of the simulated rotor motion equation for determining the energy storage configuration requirement of the VSG based on the virtual inertia and the control target of the virtual synchronous machine VSG is: Among them, J vsg is the virtual inertia time constant, P m is the mechanical power, P e is the electromagnetic power, δ is the power angle, D is the damping coefficient, ω g is the actual angular frequency of the power grid, ω0 is the rated angular frequency, and ω is the VSG angular frequency; The expression of the power of the energy storage that meets the preset maximum demand condition is: Among them, P e is the electromagnetic power, t pmax is the moment of peak energy storage power; The expression of the energy storage capacity requirement is: AND VSG =And min -AND G , Among them, E min is the required inertia of the target area to meet the preset minimum conditions, E G The inertia of the thermal power unit comes from the rotor kinetic energy.

6. The method according to claim 5, characterized in that In the calculation of the virtual inertia of the new energy power generation facility based on the total inertia demand of the target area, when the new energy power generation facility performs energy storage equivalent replacement, the expression of energy storage capacity configuration is: AND VSG =And G , Among them, E G The inertia of the thermal power unit comes from the rotor kinetic energy.

7. A virtual synchronous machine energy storage configuration device based on inertia demand, characterized in that: include: An acquisition module, used to acquire the frequency change rate of the target power system and a frequency safety threshold that meets a preset minimum point condition; A first determination module is used to determine the total inertia time constant requirement of the target area according to the frequency change rate and the frequency safety threshold; A second determination module is used to determine the total inertia demand of the target area based on the total inertia time constant demand and according to the actual inertia of the thermal power units in the target area and the actual demand of the new energy power generation facilities; A calculation module, used for calculating the virtual inertia of the new energy power generation facility based on the total inertia demand of the target area; The energy storage configuration module is used to determine the energy storage configuration requirements of the VSG based on the virtual inertia and the control target of the virtual synchronous machine VSG, and generate an energy storage configuration plan for the target power system according to the energy storage configuration requirements.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement a virtual synchronous machine energy storage configuration method based on inertia demand as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement a virtual synchronous machine energy storage configuration method based on inertia demand as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that The computer program is executed to implement a virtual synchronous machine energy storage configuration method based on inertia demand as described in any one of claims 1 to 6.

Images