Method and device for establishing transformer substation load model

Abstract

The invention provides a method and device for establishing a transformer substation load model, and the method comprises the steps: collecting the data of a network construction type energy storage system, the data of static load equipment, the data of an induction motor and the data of a transformer substation transmitting end of a power distribution and supply region of a transformer substation for the power distribution and supply region of the transformer substation comprising a plurality of network construction type energy storage equipment; respectively calculating an aggregation equivalent parameter of the network construction type energy storage system, and a static load equivalent parameter, a dynamic load equivalent parameter and a dynamic reactive power compensation parameter of the power distribution and supply area, and then establishing an equivalent network construction type energy storage system model, an equivalent static load model and an equivalent reactive power compensation model; and an equivalent dynamic load model and a reactive compensation model form a comprehensive load model comprising the network-forming energy storage system. The method and the device can accurately represent the comprehensive load model after the system formed by a plurality of pieces of network-forming type energy storage equipment is added, and overcome the defect that the traditional dynamic load model cannot describe the influence of network-forming type energy storage on the characteristics of the power grid.

Description

Technical Field

[0001] The present invention relates to the technical field of power system safety and stability analysis, and more specifically, to a method and device for establishing a substation load model. Background Art

[0002] The low inertia and low damping characteristics of the dual-high power system make the power grid face severe challenges in terms of frequency, voltage and other stability issues. In the grid-following (GFL) control mode of the converter, in order to keep synchronized with the grid, it is necessary to measure and obtain the phase information of the point of common coupling (PCC) through the phase-locked loop (PLL). However, in the case of weak grids and low physical inertia, the grid-following control mode will face stability problems. At this time, the converter is more suitable for grid-forming (GFM) control mode. The grid-forming converter has the ability to regulate frequency and control voltage, so that it can provide inertia support like a synchronous generator. The grid-forming energy storage has the advantages of energy storage and fast power response. It can not only provide energy balance services for the power grid, but also provide a wider range and longer duration of stable support. Therefore, in recent years, grid-forming energy storage devices have been increasingly used in power systems and have become a research and development hotspot in recent years. At present, the research on grid-type energy storage mainly focuses on the construction of grid-type energy storage equipment models and the analysis of the stability of power systems caused by grid-type energy storage equipment. These works provide important technical support for the research and analysis of the grid-connected characteristics of centralized grid-type energy storage systems and the development of new control methods. However, many 330kV (or 220kV) substations are equipped with multiple grid-type energy storage devices. If each grid-type energy storage device is modeled in detail in the simulation calculation of the large power grid of the power system, it will cause a dimensional disaster and cannot meet the requirements in terms of simulation speed and parameter setting. Therefore, it is necessary to establish a comprehensive load model that considers the grid-type energy storage system for substations with a grid-type energy storage system composed of multiple grid-type energy storage devices, so as to overcome the shortcomings of the traditional dynamic load model that cannot describe the impact of the grid-type energy storage system on the characteristics of the power grid. Summary of the invention

[0003] In order to solve the technical problems that when the load model of the substation in the prior art is used for large power grid simulation calculation, modeling for each grid-forming energy storage device will cause dimensionality disaster, resulting in the simulation speed and parameter setting being unable to meet the simulation requirements, and the traditional dynamic load model is unable to describe the impact of the energy storage device on the grid characteristics when the grid is formed, the present invention provides a method and device for establishing a substation load model.

[0004] According to one aspect of the present invention, the present invention provides a method for establishing a substation load model, the method comprising:

[0005] Collect grid-connected energy storage system data, static load equipment data, induction motor data and substation sending-end data in the substation power distribution area;

[0006] According to the grid-type energy storage system data, calculating the aggregated equivalent parameters of the grid-type energy storage system, and establishing an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system;

[0007] Calculating static load equivalent parameters of the power distribution area according to the static load equipment data, and establishing a static load equivalent model based on the static load equivalent parameters;

[0008] Calculating the dynamic load equivalent parameters of the power distribution area according to the induction motor data, and establishing an equivalent dynamic load model based on the dynamic load equivalent parameters;

[0009] Calculate reactive power compensation parameters of the power distribution area according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, and establish a reactive power compensation model based on the reactive power compensation parameters;

[0010] A comprehensive load model including a grid-type energy storage system is constructed based on the equivalent grid-type energy storage system model, the equivalent static load model, the equivalent dynamic load model and the reactive power compensation model.

[0011] Optionally, the collection of grid-connected energy storage system data, induction motor data, static load equipment data and substation sending-end data in the power distribution area of ​​the substation includes:

[0012] Collect the rated capacity, maximum active output, maximum reactive output, actual active output, actual reactive output, connection reactance of N energy storage devices to the common connection point PCC, line reactance and transformer reactance of N energy storage devices in the grid-type energy storage system, as well as the transient time constant of the model of N energy storage devices, the time constant of the equivalent virtual synchronization module, virtual damping, the regulator gain of the equivalent virtual excitation control module, the proportional integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant, the synchronous reactance, and the d-axis transient reactance;

[0013] Collect the rated active power, rated reactive power and rated voltage of several static load devices in the substation, as well as the actual reactive output;

[0014] Collect the rated active power, rated reactive power, rated phase voltage, rated electromagnetic power, maximum electromagnetic power, kinetic energy, rotor winding copper loss and actually absorbed reactive power of several induction motors in the substation;

[0015] Collect reactive power at the sending end of the substation.

[0016] Optionally, calculating the aggregated equivalent parameters of the grid-type energy storage system according to the grid-type energy storage system data, and establishing an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system, comprises:

[0017] The rated capacity, maximum active output, maximum reactive output, actual active output, and actual reactive output of N energy storage devices in the grid-type energy storage system are summed up to determine the equivalent rated capacity, equivalent maximum active output, equivalent maximum reactive output, equivalent actual active output, and equivalent actual reactive output of the grid-type energy storage system;

[0018] According to the connection reactance, line reactance and transformer reactance of N energy storage devices in the grid-type energy storage system to the common connection point PCC, the equivalent reactance is determined, and the calculation formula is:

[0019]

[0020] X′ C,n =X C,n +X L,n +X T,n

[0021] In the formula, X′ C,n , X C,n , X L,n and X T,n are the equivalent reactance, connection reactance, line reactance and transformer reactance of the nth grid-connected energy storage device connected to the PCC, respectively, and X C,EQ is the equivalent reactance of the grid-type energy storage system;

[0022] According to the virtual damping of the equivalent virtual synchronization module in the model of N energy storage devices in the grid-type energy storage system, the equivalent virtual damping of the grid-type energy storage system is determined, and the calculation formula is:

[0023]

[0024] Where D n is the virtual damping of the equivalent virtual synchronization module in the model of the nth grid-connected energy storage device, D EQ is the equivalent virtual damping of the grid-type energy storage system;

[0025] According to the maximum active output of the N energy storage devices in the grid-type energy storage system and the time constant of the equivalent virtual synchronization module of the corresponding device model, the time constant of the equivalent virtual synchronization module of the grid-type energy storage system is determined, and the calculation formula is:

[0026]

[0027] Where, T j,EQ is the time constant of the equivalent virtual synchronization module of the grid-connected energy storage system, P max,n is the maximum active output of the nth grid-connected energy storage device, T j,n is the time constant of the equivalent virtual synchronization module of the model of the nth grid-connected energy storage device;

[0028] According to the synchronous reactance and d-axis transient reactance of the models of N energy storage devices in the grid-type energy storage system, the equivalent synchronous reactance and equivalent d-axis transient reactance of the grid-type energy storage system are determined respectively, and the calculation formula is:

[0029]

[0030] In the formula, X d,n and X′ d,n are the equivalent synchronous reactance and equivalent d-axis transient reactance of the model of the nth grid-connected energy storage device, respectively, X d,EQ and X′ d,EQ are the equivalent synchronous reactance and the equivalent d-axis transient reactance of the grid-type energy storage system respectively;

[0031] According to the maximum active output of N energy storage devices in the grid-type energy storage system and the transient time constant of the corresponding device model, the proportional-integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant and the regulator gain of the equivalent virtual excitation control module, the equivalent transient time constant, the equivalent proportional-integral selection factor, the equivalent first voltage regulator time constant, the equivalent second voltage regulator time constant, the equivalent filter time constant and the regulator gain of the equivalent virtual excitation control module of the grid-type energy storage system are determined, and the calculation formulas are:

[0032]

[0033]

[0034] In the formula, Q max,n is the maximum active output of the nth energy storage device, T′ d0,n , k n , T 1,n , T 2,n , T R,n and k V,n are the transient time constant of the model of the nth energy storage device, the proportional integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant and the regulator gain of the equivalent virtual excitation control module, T′ d0,EQ , k EQ , T 1,eQ , T2,EQ , T R,EQ and k V,EQ They are respectively the equivalent transient time constant, the equivalent proportional integral selection factor, the equivalent first voltage regulator time constant, the equivalent second voltage regulator time constant, the equivalent filter time constant and the equivalent regulator gain of the virtual excitation control module of the grid-type energy storage system;

[0035] An equivalent grid-type energy storage system model is established based on the equivalent rated capacity, equivalent maximum active output, equivalent maximum reactive output, equivalent actual active output, equivalent actual reactive output, equivalent reactance, equivalent virtual damping, equivalent synchronous reactance and equivalent d-axis transient reactance, equivalent transient time constant, equivalent proportional-integral selection factor, equivalent first voltage regulator time constant, equivalent second voltage regulator time constant, equivalent filter time constant and equivalent virtual excitation control module regulator gain of the grid-type energy storage system.

[0036] Optionally, calculating the static load equivalent parameters of the power distribution area according to the static load equipment data, and establishing a static load equivalent model based on the static load equivalent parameters includes:

[0037] Based on the ZIP model principle of constant impedance, constant current and constant power, the static load equivalent parameters are determined according to the rated active power, rated reactive power and rated voltage of the static load equipment in the substation;

[0038] An equivalent static load model is established based on the equivalent parameters of static load.

[0039] Optionally, calculating the dynamic load equivalent parameters of the power distribution area according to the induction motor data, and establishing an equivalent dynamic load model based on the dynamic load equivalent parameters, includes:

[0040] According to the principle of keeping the total rated active power and reactive power absorbed by the load nodes in the power distribution area unchanged, the total electromagnetic power, maximum electromagnetic power and total kinetic energy unchanged, and the total rotor winding copper loss unchanged, the dynamic load equivalent parameters are calculated according to the rated active power, rated reactive power, rated phase voltage, rated electromagnetic power, maximum electromagnetic power, kinetic energy and rotor winding copper loss of the induction motor of the substation;

[0041] An equivalent dynamic load model is established based on the equivalent parameters of dynamic load.

[0042] Optionally, the calculating of reactive compensation parameters of the power distribution area according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, and establishing a reactive compensation model based on the reactive compensation parameters includes:

[0043] Based on the reactive power balance principle, the reactive compensation parameters of the power distribution area are calculated according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, wherein the reactive compensation parameter calculation formula is:

[0044] -Q SC =Q-(Q IM +Q Z +Q I +Q P -Q EQ )

[0045] In the formula, Q SC is the reactive power compensation parameter of the power distribution area, Q is the reactive power at the sending end of the substation, and Q IM Q is the sum of reactive power actually absorbed by several induction motors in the substation. Z , Q I and Q P They are the sum of the actual reactive power outputs of all static constant impedance load devices in the substation, the sum of the actual reactive power outputs of all static constant current load devices in the substation, and the actual reactive power outputs of all static constant power load devices. EQ is the sum of the actual reactive power outputs of N grid-type energy storage devices in the grid-type energy storage system;

[0046] Based on the reactive power compensation parameter Q SC Establish reactive power compensation model.

[0047] According to another aspect of the present invention, the present invention provides a device for establishing a substation load model, the device comprising:

[0048] Data acquisition module, used to collect grid-type energy storage system data, static load equipment data, induction motor data and substation sending end data in the power distribution area of ​​the substation;

[0049] A first model module is used to calculate the aggregated equivalent parameters of the grid-type energy storage system according to the grid-type energy storage system data, and to establish an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system;

[0050] A second model module is used to calculate the static load equivalent parameters of the power distribution area according to the static load equipment data, and establish a static load equivalent model based on the static load equivalent parameters;

[0051] A third model module is used to calculate the dynamic load equivalent parameters of the power distribution area according to the induction motor data, and establish an equivalent dynamic load model based on the dynamic load equivalent parameters;

[0052] A fourth model module is used to calculate reactive compensation parameters of the power distribution area according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, and establish a reactive compensation model based on the reactive compensation parameters;

[0053] The load model module is used to construct a comprehensive load model including a grid-type energy storage system based on the equivalent grid-type energy storage system model, the equivalent static load model, the equivalent dynamic load model and the reactive power compensation model.

[0054] Optionally, the data acquisition module collects grid-type energy storage system data, induction motor data, static load equipment data and substation sending-end data in the power distribution area of ​​the substation, including:

[0055] Collect the rated capacity, maximum active output, maximum reactive output, actual active output, actual reactive output, connection reactance of N energy storage devices to the common connection point PCC, line reactance and transformer reactance of N energy storage devices in the grid-type energy storage system, as well as the transient time constant of the model of N energy storage devices, the time constant of the equivalent virtual synchronization module, virtual damping, the regulator gain of the equivalent virtual excitation control module, the proportional integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant, the synchronous reactance, and the d-axis transient reactance;

[0056] Collect the rated active power, rated reactive power and rated voltage of several static load devices in the substation, as well as the actual reactive output;

[0057] Collect the rated active power, rated reactive power, rated phase voltage, rated electromagnetic power, maximum electromagnetic power, kinetic energy, rotor winding copper loss and actually absorbed reactive power of several induction motors in the substation;

[0058] Collect reactive power at the sending end of the substation.

[0059] Optionally, the first model module calculates the aggregated equivalent parameters of the grid-type energy storage system according to the grid-type energy storage system data, and establishes an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system, including:

[0060] The rated capacity, maximum active output, maximum reactive output, actual active output, and actual reactive output of N energy storage devices in the grid-type energy storage system are summed up to determine the equivalent rated capacity, equivalent maximum active output, equivalent maximum reactive output, equivalent actual active output, and equivalent actual reactive output of the grid-type energy storage system;

[0061] According to the connection reactance, line reactance and transformer reactance of N energy storage devices in the grid-type energy storage system to the common connection point PCC, the equivalent reactance is determined, and the calculation formula is:

[0062]

[0063] X′ C,n =X C,n +X L,n +X T,n

[0064] In the formula, X′ C,n , X C,n , X L,n and X T,n are the equivalent reactance, connection reactance, line reactance and transformer reactance of the nth grid-connected energy storage device connected to the PCC, respectively, and X C,EQ is the equivalent reactance of the grid-type energy storage system;

[0065] According to the virtual damping of the equivalent virtual synchronization module in the model of N energy storage devices in the grid-type energy storage system, the equivalent virtual damping of the grid-type energy storage system is determined, and the calculation formula is:

[0066]

[0067] Where D n is the virtual damping of the equivalent virtual synchronization module in the model of the nth grid-connected energy storage device, D EQ is the equivalent virtual damping of the grid-type energy storage system;

[0068] According to the maximum active output of the N energy storage devices in the grid-type energy storage system and the time constant of the equivalent virtual synchronization module of the corresponding device model, the time constant of the equivalent virtual synchronization module of the grid-type energy storage system is determined, and the calculation formula is:

[0069]

[0070] Where, T j,EQ is the time constant of the equivalent virtual synchronization module of the grid-connected energy storage system, P max,n is the maximum active output of the nth grid-connected energy storage device, T j,n is the time constant of the equivalent virtual synchronization module of the model of the nth grid-connected energy storage device;

[0071] According to the synchronous reactance and d-axis transient reactance of the models of N energy storage devices in the grid-type energy storage system, the equivalent synchronous reactance and equivalent d-axis transient reactance of the grid-type energy storage system are determined respectively, and the calculation formula is:

[0072]

[0073] In the formula, X d,n and X′ d,n are the equivalent synchronous reactance and equivalent d-axis transient reactance of the model of the nth grid-connected energy storage device, respectively, X d,EQ and X′ d,EQ are the equivalent synchronous reactance and the equivalent d-axis transient reactance of the grid-type energy storage system respectively;

[0074] According to the maximum active output of N energy storage devices in the grid-type energy storage system and the transient time constant of the corresponding device model, the proportional-integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant and the regulator gain of the equivalent virtual excitation control module, the equivalent transient time constant, the equivalent proportional-integral selection factor, the equivalent first voltage regulator time constant, the equivalent second voltage regulator time constant, the equivalent filter time constant and the regulator gain of the equivalent virtual excitation control module of the grid-type energy storage system are determined, and the calculation formulas are:

[0075]

[0076] In the formula, Q max,n is the maximum active output of the nth energy storage device, T′ d0,n , k n , T 1,n , T 2,n , T R,n and k V,n are the transient time constant of the model of the nth energy storage device, the proportional integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant and the regulator gain of the equivalent virtual excitation control module, T′ d0,EQ , k EQ , T 1,EQ , T 2,EQ , T R,EQ and k V,EQ They are respectively the equivalent transient time constant, the equivalent proportional integral selection factor, the equivalent first voltage regulator time constant, the equivalent second voltage regulator time constant, the equivalent filter time constant and the equivalent regulator gain of the virtual excitation control module of the grid-type energy storage system;

[0077] An equivalent grid-type energy storage system model is established based on the equivalent rated capacity, equivalent maximum active output, equivalent maximum reactive output, equivalent actual active output, equivalent actual reactive output, equivalent reactance, equivalent virtual damping, equivalent synchronous reactance and equivalent d-axis transient reactance, equivalent transient time constant, equivalent proportional-integral selection factor, equivalent first voltage regulator time constant, equivalent second voltage regulator time constant, equivalent filter time constant and equivalent virtual excitation control module regulator gain of the grid-type energy storage system.

[0078] Optionally, the second model module calculates static load equivalent parameters of the power distribution area according to the static load equipment data, and establishes a static load equivalent model based on the static load equivalent parameters, including:

[0079] Based on the ZIP model principle of constant impedance, constant current and constant power, the static load equivalent parameters are determined according to the rated active power, rated reactive power and rated voltage of the static load equipment in the substation;

[0080] An equivalent static load model is established based on the equivalent parameters of static load.

[0081] Optionally, the third model module calculates dynamic load equivalent parameters of the power distribution area according to the induction motor data, and establishes an equivalent dynamic load model based on the dynamic load equivalent parameters, including:

[0082] According to the principle of keeping the total rated active power and reactive power absorbed by the load nodes in the power distribution area unchanged, the total electromagnetic power, maximum electromagnetic power and total kinetic energy unchanged, and the total rotor winding copper loss unchanged, the dynamic load equivalent parameters are calculated according to the rated active power, rated reactive power, rated phase voltage, rated electromagnetic power, maximum electromagnetic power, kinetic energy and rotor winding copper loss of the induction motor of the substation;

[0083] An equivalent dynamic load model is established based on the equivalent parameters of dynamic load.

[0084] Optionally, the fourth model module calculates reactive compensation parameters of the power distribution area according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, and establishes a reactive compensation model based on the reactive compensation parameters, including:

[0085] Based on the reactive power balance principle, the reactive compensation parameters of the power distribution area are calculated according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, wherein the reactive compensation parameter calculation formula is:

[0086] -Q SC =Q-(Q IM +QZ +Q I +Q P -Q EQ )

[0087] In the formula, Q SC is the reactive power compensation parameter of the power distribution area, Q is the reactive power at the sending end of the substation, and Q IM Q is the sum of reactive power actually absorbed by several induction motors in the substation. Z , Q I and Q P They are the sum of the actual reactive power outputs of all static constant impedance load devices in the substation, the sum of the actual reactive power outputs of all static constant current load devices in the substation, and the actual reactive power outputs of all static constant power load devices. EQ is the sum of the actual reactive power outputs of N grid-type energy storage devices in the grid-type energy storage system;

[0088] Based on the reactive power compensation parameter Q SC Establish reactive power compensation model.

[0089] In the method and device for establishing a substation load model provided by the present invention, the method collects grid-type energy storage system data, static load equipment data, induction motor data and substation sending-end data of the substation in the distribution and power supply area, for a substation including multiple grid-type energy storage devices in the distribution and power supply area of ​​the substation; calculates the aggregated equivalent parameters of the grid-type energy storage system based on the data of the grid-type energy storage system, and establishes an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system; calculates the static load equivalent parameters of the distribution and power supply area based on the static load equipment data, and establishes an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system; The method and device can accurately characterize the comprehensive load model after the system composed of multiple grid-type energy storage devices is added, and overcomes the disadvantage that the traditional dynamic load model cannot describe the influence of grid-type energy storage on the characteristics of the power grid. The achievements of the present invention can be widely applied to load modeling software containing grid-type energy storage systems, and the generated load model parameters of the grid-type energy storage systems can be fully applied to power grid simulation calculation, planning and design, improve the accuracy of power grid simulation calculation, and provide more accurate simulation analysis results for power grid analysis and decision making. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0091] Figure 1 A flowchart of a method for establishing a substation load model according to a preferred embodiment of the present invention;

[0092] Figure 2 A structural schematic diagram of a model of a single grid-type energy storage device according to a preferred embodiment of the present invention;

[0093] Figure 3 It is a structural schematic diagram of a comprehensive load model considering a grid-type energy storage system according to a preferred embodiment of the present invention;

[0094] Figure 4 A schematic diagram of a 220 kV substation including a plurality of grid-type energy storage devices according to another preferred embodiment of the present invention;

[0095] Figure 5 A schematic diagram showing a comparison of grid connection point voltage waveforms according to another preferred embodiment of the present invention;

[0096] Figure 6 A schematic diagram of active power comparison of a grid connection point according to another preferred embodiment of the present invention;

[0097] Figure 7 A schematic diagram of reactive power comparison of a grid connection point according to another preferred embodiment of the present invention;

[0098] Figure 8 A schematic diagram of the structure of a device for establishing a substation load model according to a preferred embodiment of the present invention;

[0099] Fig. 9 Schematic diagram of the structure of an electronic device according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0100] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0101] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0102] Exemplary Methods

[0103] Figure 1 FIG. 1 is a flow chart of a method for establishing a substation load model according to a preferred embodiment of the present invention. Figure 1 As shown, the method for establishing a substation load model described in this preferred embodiment starts from step 101.

[0104] In step 101, grid-connected energy storage system data, static load equipment data, induction motor data and substation sending-end data in the power distribution area of ​​the substation are collected.

[0105] In actual applications, there are many 330kV or 220kV substations with multiple grid-type energy storage devices. If each grid-type energy storage device is modeled in detail in the simulation calculation of the power system large power grid, it will cause dimensionality disaster, making the simulation speed and parameter settings unable to meet the requirements. In order to solve the above problems, this preferred implementation method designs an equivalent grid-type energy storage system model for the energy storage system composed of multiple grid-type energy storage devices, and adds an equivalent grid-type energy storage system model to the substation load model to simulate the characteristics of a large number of grid-type energy storage devices in the power supply and distribution area of ​​the load site.

[0106] In step 102, based on the grid-type energy storage system data, aggregated equivalent parameters of the grid-type energy storage system are calculated, and an equivalent grid-type energy storage system model is established based on the aggregated equivalent parameters of the grid-type energy storage system.

[0107] Figure 2 Schematic diagram of the structure of a single grid-type energy storage device according to a preferred embodiment of the present invention. Figure 2 As shown, this preferred embodiment proposes a grid-type energy storage device model considering the virtual co-frequency control characteristics. The model of a single grid-type energy storage device mainly includes two control modules, one is a virtual co-frequency control module, and the other is a virtual excitation control module. There are 11 model parameters, which are the connection reactance X of the grid-type energy storage device connected to the PCC point. c , transient time constant T d0 ′、Inertia time constant T of virtual synchronization module j , virtual damping D, regulator gain K of virtual excitation control module, proportional integral selection factor K v , the first voltage regulator time constant T1 , the second voltage regulator time constant T 2 , filter time constant T R , Synchronous Reactance X d , d-axis transient reactance X d ′.

[0108] Among them, the virtual synchronous control module realizes the synchronization capability with the power grid by comparing with the traditional synchronous machine rotor motion equation, thus introducing the risk of power angle instability of the traditional synchronous machine. The difference lies in the inertia time constant Tj and the damping coefficient D. For the synchronous machine, the two are fixed physical parameters; while for the virtual synchronous control, the two are control parameters that can be manually adjusted, so there may be differences in characteristics with the real synchronous machine. For the virtual synchronous controller, its transfer function can be transformed into a first-order inertia and integral series link. Since the damping coefficient D represents the total damping torque of the virtual synchronous machine, its value determines the key characteristics of the network-forming controller. When Tj / D is extremely small, the virtual synchronous control characteristic becomes a droop control characteristic. When Tj / D is large, the virtual synchronous control characteristic maintains a characteristic close to that of the synchronous machine. Because the supporting capacity of the grid-type energy storage device for the system frequency is mainly determined by the maximum active power of the grid-type energy storage device, therefore, in this preferred embodiment, when the grid-type energy storage system composed of multiple grid-type energy storage devices is equal, the maximum active power of each grid-type energy storage device should be used as the weighted average to calculate the virtual synchronization parameters of the equivalent grid-type energy storage system model relative to the total maximum active power of all grid-type energy storage devices in the entire load site. Similarly, the virtual excitation control module determines the voltage support capacity of the grid-type energy storage, and the influence of the grid-type energy storage on the voltage stability is mainly reflected by the amplitude of the internal potential. Voltage support can be divided into two stages during the transient process: 1) Maintaining a stable internal potential during the fault and passively providing voltage support to the system; 2) Under the action of the virtual excitation controller, the internal potential actively rises, the voltage support capacity is enhanced and continues until the system voltage returns to normal. Because the supporting capacity of the grid-type energy storage for the system voltage is mainly determined by the maximum reactive power of the grid-type energy storage, when the grid-type energy storage system composed of multiple grid-type energy storage devices is equal, the virtual excitation parameters of the equivalent grid-type energy storage model should be calculated by weighted average using the proportion of the maximum reactive power of each grid-type energy storage to the total maximum reactive power of all grid-type energy storages in the entire 220kV load site.

[0109] Preferably, the calculating of the aggregated equivalent parameters of the grid-type energy storage system according to the grid-type energy storage system data, and establishing an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system, comprises:

[0110] The rated capacity, maximum active output, maximum reactive output, actual active output, and actual reactive output of N energy storage devices in the grid-type energy storage system are summed up to determine the equivalent rated capacity, equivalent maximum active output, equivalent maximum reactive output, equivalent actual active output, and equivalent actual reactive output of the grid-type energy storage system;

[0111] According to the connection reactance, line reactance and transformer reactance of N energy storage devices in the grid-type energy storage system to the common connection point PCC, the equivalent reactance is determined, and the calculation formula is:

[0112]

[0113] X′ C,n =X C,n +X L,n +X T,n

[0114] In the formula, X′ C,n , X C,n , X L,n and X T,n are the equivalent reactance, connection reactance, line reactance and transformer reactance of the nth grid-connected energy storage device connected to the PCC, respectively, and X C,EQ is the equivalent reactance of the grid-type energy storage system;

[0115] According to the virtual damping of the equivalent virtual synchronization module in the model of N energy storage devices in the grid-type energy storage system, the equivalent virtual damping of the grid-type energy storage system is determined, and the calculation formula is:

[0116]

[0117] Where D n is the virtual damping of the equivalent virtual synchronization module in the model of the nth grid-connected energy storage device, D EQ is the equivalent virtual damping of the grid-type energy storage system;

[0118] According to the maximum active output of the N energy storage devices in the grid-type energy storage system and the time constant of the equivalent virtual synchronization module of the corresponding device model, the time constant of the equivalent virtual synchronization module of the grid-type energy storage system is determined, and the calculation formula is:

[0119]

[0120] Where, T j,EQ is the time constant of the equivalent virtual synchronization module of the grid-connected energy storage system, P max,n is the maximum active output of the nth grid-connected energy storage device, T j,n is the time constant of the equivalent virtual synchronization module of the model of the nth grid-connected energy storage device;

[0121] According to the synchronous reactance and d-axis transient reactance of the models of N energy storage devices in the grid-type energy storage system, the equivalent synchronous reactance and equivalent d-axis transient reactance of the grid-type energy storage system are determined respectively, and the calculation formula is:

[0122]

[0123] In the formula, X d,n and X′ d,n are the equivalent synchronous reactance and equivalent d-axis transient reactance of the model of the nth grid-connected energy storage device, respectively, X d,EQ and X′ d,EQ are the equivalent synchronous reactance and the equivalent d-axis transient reactance of the grid-type energy storage system respectively;

[0124] According to the maximum active output of N energy storage devices in the grid-type energy storage system and the transient time constant of the corresponding device model, the proportional-integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant and the regulator gain of the equivalent virtual excitation control module, the equivalent transient time constant, the equivalent proportional-integral selection factor, the equivalent first voltage regulator time constant, the equivalent second voltage regulator time constant, the equivalent filter time constant and the regulator gain of the equivalent virtual excitation control module of the grid-type energy storage system are determined, and the calculation formulas are:

[0125]

[0126] In the formula, Q max,n is the maximum active output of the nth energy storage device, T′ d0,n , k n , T 1,n , T 2,n , T R,n and k V,n are the transient time constant of the model of the nth energy storage device, the proportional integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant and the regulator gain of the equivalent virtual excitation control module, T′ d0,EQ , k EQ , T 1,EQ , T 2,EQ , T R,EQ and k V,EQ They are respectively the equivalent transient time constant, the equivalent proportional integral selection factor, the equivalent first voltage regulator time constant, the equivalent second voltage regulator time constant, the equivalent filter time constant and the equivalent regulator gain of the virtual excitation control module of the grid-type energy storage system;

[0127] An equivalent grid-type energy storage system model is established based on the equivalent rated capacity, equivalent maximum active output, equivalent maximum reactive output, equivalent actual active output, equivalent actual reactive output, equivalent reactance, equivalent virtual damping, equivalent synchronous reactance and equivalent d-axis transient reactance, equivalent transient time constant, equivalent proportional-integral selection factor, equivalent first voltage regulator time constant, equivalent second voltage regulator time constant, equivalent filter time constant and equivalent virtual excitation control module regulator gain of the grid-type energy storage system.

[0128] In step 103, static load equivalent parameters of the power distribution area are calculated according to the static load equipment data, and a static load equivalent model is established based on the static load equivalent parameters.

[0129] Preferably, calculating the static load equivalent parameters of the power distribution area according to the static load equipment data, and establishing a static load equivalent model based on the static load equivalent parameters includes:

[0130] Based on the ZIP model principle of constant impedance, constant current and constant power, the static load equivalent parameters are determined according to the rated active power, rated reactive power and rated voltage of the static load equipment in the substation;

[0131] An equivalent static load model is established based on the equivalent parameters of static load.

[0132] Specifically, the equivalent static load model described in this preferred embodiment describes the relationship between load power and voltage as a polynomial load model in the form of a polynomial equation. The general form of the model is as follows:

[0133]

[0134] The above load model is called ZIP model because it contains constant impedance Z, constant current I and constant power P. This model is used to describe specific load equipment or load elements, that is, load equipment or load elements with any one of the characteristics of constant impedance Z, constant current I and constant power P. In the above formula, the polynomial active power load model coefficients are a, b, c, the reactive power load model coefficients are α, β, γ, Vo represents the rated voltage of the load, Po and Qo represent the rated active power and reactive power of the load at the rated voltage Vo, respectively. If this model is used to describe the comprehensive load of the bus, Vo, Po and Qo are usually used to represent the values ​​under the initial operating conditions of the system.

[0135] The equivalent values ​​for static loads are mainly the equivalent values ​​of coefficients Po, a, b, c and Qo, α, β, γ. The equivalent values ​​for polynomial load models are based on the sensitivity of load power to load terminal voltage, that is,

[0136]

[0137] P1, P2…Pn and Q1, Q2…Qn are the active power and reactive power of each static load, and the corresponding polynomial load model coefficients are Po1…Pon, a1…an, b1…bn, c1…cn and Qo1…Qon, α1…αn, β1…βn, γ1…γn. When V=Vo, we have:

[0138]

[0139] According to the above formula, by substituting the collected data values, the equivalent parameters of the static load can be solved, and then the equivalent static load model can be established according to the solved equivalent parameters of the static load.

[0140] In step 104, dynamic load equivalent parameters of the power distribution area are calculated according to the induction motor data, and an equivalent dynamic load model is established based on the dynamic load equivalent parameters.

[0141] Preferably, the calculating of the dynamic load equivalent parameters of the power distribution area according to the induction motor data, and establishing an equivalent dynamic load model based on the dynamic load equivalent parameters, comprises:

[0142] According to the principle of keeping the total rated active power and reactive power absorbed by the load nodes in the power distribution area unchanged, the total electromagnetic power, maximum electromagnetic power and total kinetic energy unchanged, and the total rotor winding copper loss unchanged, the dynamic load equivalent parameters are calculated according to the rated active power, rated reactive power, rated phase voltage, rated electromagnetic power, maximum electromagnetic power, kinetic energy and rotor winding copper loss of the induction motor of the substation;

[0143] An equivalent dynamic load model is established based on the equivalent parameters of dynamic load.

[0144] Specifically, the preferred embodiment calculates the dynamic load equivalent parameters of the power distribution area according to the collected induction motor data, including:

[0145] The formula for calculating the total stator winding copper loss ∑Pcu1, the rated slip Sn of the equivalent motor and the equivalent inertia time constant H is as follows:

[0146]

[0147] Where, Pemn and Pn are the rated electromagnetic power and rated active power of the nth motor, Pcu2 and Eenergy are the rotor winding copper loss and kinetic energy of the nth motor, respectively.

[0148] Among them, ∑Pemn-∑Pcu2 is the rated mechanical power output by the equivalent motor, which remains unchanged;

[0149] Calculate the electrical parameters of the equivalent motor model, including stator resistance Rs, stator leakage reactance Xs, rotor resistance Rr, rotor leakage reactance Xr and magnetizing reactance Xm. Assuming the rated phase voltage is Un, the calculation process of the electrical parameters is as follows:

[0150] Let Pemt_max = ∑Pemn_max; Pent_max is the total maximum electromagnetic power, Pemn_max is the maximum electromagnetic power of the nth motor;

[0151] Assume the total stator phase current is I n , and its calculation formula is as follows:

[0152]

[0153] Among them, Pn, Qn and Un are the rated active power, rated reactive power and rated phase voltage of the nth motor respectively;

[0154]

[0155] Among them, P cul is the total stator winding copper loss of the equivalent motor, In is the total stator phase current;

[0156] Calculate the equivalent impedance Zdeq of the equivalent motor, the calculation formula is:

[0157]

[0158] Rdeq=real(Zdeq)

[0159] Xdeq=imag(Zdeq)

[0160] Among them, R dep is the equivalent resistance of the equivalent motor, X dep is the equivalent reactance of the equivalent motor, j is the imaginary unit of the complex number;

[0161] Calculate the stator leakage reactance Xs and rotor leakage reactance Xr, the calculation formula is:

[0162]

[0163] Xr=Xs

[0164] In this algorithm, it is always assumed that Xr = Xs, and Xs and Xr calculated according to the above formula are bound to be smaller, because the maximum electromagnetic power calculated according to the simplified maximum electromagnetic power formula is larger than the actual maximum electromagnetic power, so Xs and Xr need to be corrected by an iterative method;

[0165] According to the calculated stator resistance Rs, stator leakage reactance Xs, rotor leakage reactance Xr and equivalent impedance Zdeq = Rdeq + jXdeq, the rotor resistance Rr and magnetizing reactance Xm are calculated so that Pem = ∑Pemn holds true, where K r K is the difference between the equivalent resistance of the equivalent motor and the stator resistance. x is the difference between the equivalent reactance of the equivalent motor and the stator reactance:

[0166] Kr=Rdeq-Rs

[0167] Kx=Xdeq-Xs

[0168]

[0169] According to the obtained Rs, Xs, Rt, Xr and Xm, the maximum electromagnetic power is recalculated according to the simplified formula:

[0170]

[0171] According to the Thevenin equivalent circuit, the actual maximum electromagnetic power under the new parameters is calculated:

[0172] Thevenin equivalent impedance is:

[0173]

[0174] Rdp = real(Zdp)

[0175] Xdp=imag(Zdp)

[0176] Among them, R dp is the Thevenin equivalent resistance, X dp is the Thevenin equivalent reactance, Z dp is the Thevenin equivalent impedance; the condition for generating maximum electromagnetic power is:

[0177]

[0178] Among them, S m is the critical slip, R pm is the Thevenin equivalent impedance value corresponding to the maximum electromagnetic power; the open circuit voltage of the Thevenin equivalent circuit is:

[0179]

[0180] Recalculate the actual maximum electromagnetic torque corresponding to the new parameters according to the following formula:

[0181]

[0182] Calculate the ratio of Pemt_maxi to Pem_maxi and correct Pemt_max:

[0183]

[0184] Pemt_max=kmaxiPem_max

[0185] Compare the difference between Pem_maxi and Pem_max:

[0186] ErrPem_max=|Pem_max-[em_maxi|

[0187] If ErrPem_max ≥ 1.0e -5 , then recalculate the stator leakage reactance Xs and rotor leakage reactance Xr, otherwise end the calculation.

[0188] After obtaining the total stator winding copper loss, rated slip, equivalent inertia time constant, and electrical parameters of the above-mentioned equivalent motor, an equivalent dynamic load model is generated according to the above-mentioned parameters.

[0189] In step 105, reactive compensation parameters of the power distribution area are calculated according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, and a reactive compensation model is established based on the reactive compensation parameters.

[0190] Preferably, the reactive compensation parameters of the power distribution area are calculated according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, and a reactive compensation model is established based on the reactive compensation parameters, including:

[0191] Based on the reactive power balance principle, the reactive compensation parameters of the power distribution area are calculated according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, wherein the reactive compensation parameter calculation formula is:

[0192] -Q SC =Q-(Q IM +Q Z +Q I +Q P -Q EQ )

[0193] In the formula, Q SC is the reactive power compensation parameter of the power distribution area, Q is the reactive power at the sending end of the substation, and Q IM Q is the sum of reactive power actually absorbed by several induction motors in the substation. Z , Q I and Q PThey are the sum of the actual reactive power outputs of all static constant impedance load devices in the substation, the sum of the actual reactive power outputs of all static constant current load devices in the substation, and the actual reactive power outputs of all static constant power load devices. EQ is the sum of the actual reactive power outputs of N grid-type energy storage devices in the grid-type energy storage system;

[0194] Based on the reactive power compensation parameter Q SC Establish reactive power compensation model.

[0195] In step 106, a comprehensive load model including a grid-type energy storage system is constructed based on the equivalent grid-type energy storage system model, the equivalent static load model, the equivalent dynamic load model and the reactive power compensation model.

[0196] Figure 3 Schematic diagram of the structure of the load model of the grid-type energy storage system according to the preferred embodiment of the present invention. Figure 3 As shown, the load model in this preferred embodiment is divided into four main parts, namely, an equivalent grid-type energy storage model, an equivalent static load model, an equivalent dynamic load model and a reactive power compensation model. Among them, the equivalent static load includes a constant impedance load, a constant current load and a constant power load.

[0197] Figure 4 FIG. 2 is a schematic diagram of a 220 kV substation including multiple grid-type energy storage devices according to another preferred embodiment of the present invention. Figure 4 As shown, in this preferred implementation mode, the 220kV substation obtained through investigation is taken as an example for analysis and explanation. The 220kV substation is equipped with 8 grid-type energy storage devices G1-G8, and their operating characteristic parameters are shown in Table 1 and Table 1.

[0198] Table 1

[0199]

[0200]

[0201] Table 1

[0202] K Kv <![CDATA[T 1 (s)]]> <![CDATA[T 2 (s)]]> <![CDATA[T R (s)]]> <![CDATA[X d (pu)]]> <![CDATA[X d ′(pu)]]> Network type G1 7 0.9 2.0 0.5 0.03 2.41 0.259 Network type G2 12 0.5 2.0 0.5 0.01 3.5 0.45 Network Type G3 10 0.8 2.0 0.5 0.02 2.5 0.31 Network Type G4 5 0.7 2.0 0.5 0.05 2.1 0.2 Network Type G5 6 0.6 2.0 0.5 0.04 2.3 0.21 Network type G6 7 0.9 2.0 0.5 0.03 2.41 0.259 Network Type G7 12 0.5 2.0 0.5 0.01 3.5 0.45 Network Type G8 5 0.7 2.0 0.5 0.05 2.1 0.2

[0203] The aggregated equivalent parameters obtained by the method for constructing an equivalent grid-type energy storage system model described in the present invention are shown in Table 2 and Table 2.

[0204] Table 2

[0205]

[0206] Table 2

[0207] K Kv <![CDATA[T 1 (s)]]> <![CDATA[T 2 (s)]]> <![CDATA[T R (s)]]> <![CDATA[X d (pu)]]> <![CDATA[X d ′(pu)]]> 8.5 0.69 2.0 0.5 0.027 0.31 0.033

[0208] After obtaining the equivalent parameters of static load, dynamic load and reactive compensation parameters by the method described in this preferred embodiment, an equivalent model considering the grid-type energy storage system is established to carry out power system simulation, and the results of transient simulation using a detailed distribution network model of 8 grid-type energy storage devices are compared, wherein: Figure 5 This is a schematic diagram of a comparison of grid connection point voltage waveforms according to another preferred embodiment of the present invention. Figure 6 This is a schematic diagram of active power comparison of a grid connection point according to another preferred embodiment of the present invention. Figure 7 FIG. 1 is a schematic diagram showing a comparison of reactive power at a grid connection point according to another preferred embodiment of the present invention. Figure 5 , Figure 6 and Figure 7 As shown, it can be seen that the voltage waveforms, active power waveforms and reactive power waveforms of the comprehensive load model and the detailed distribution network model generated by the method for establishing a load model described in the present invention are highly overlapped, indicating that the model considering the grid-type energy storage system established based on the method described in the present invention can well reflect the load characteristics of the active distribution network containing multiple grid-type energy storage devices.

[0209] The method for establishing a load model described in this preferred embodiment is aimed at a substation whose power distribution area includes a grid-type energy storage system composed of multiple grid-type energy storage devices, and collects grid-type energy storage system data, static load equipment data, induction motor data and substation sending-end data in the power distribution area of ​​the substation; calculates the aggregated equivalent parameters of the grid-type energy storage system based on the data of the grid-type energy storage system, and establishes an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system; calculates the static load equivalent parameters of the power distribution area based on the static load equipment data, and The method is to establish a static load equivalent model based on equivalent parameters; calculate the dynamic load equivalent parameters of the power distribution area according to the induction motor data, and establish an equivalent dynamic load model based on the dynamic load equivalent parameters; calculate the reactive compensation parameters of the power distribution area according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, and establish a reactive compensation model based on the reactive compensation parameters; construct a comprehensive load model including the grid-type energy storage system based on the equivalent grid-type energy storage system model, equivalent static load model, equivalent dynamic load model and reactive compensation model. The method can accurately characterize the comprehensive load model after the system composed of multiple grid-type energy storage devices is added, and overcomes the disadvantage that the traditional dynamic load model cannot describe the influence of grid-type energy storage on the characteristics of the power grid. The results of this preferred implementation method can be widely applied to the load modeling software including the grid-type energy storage system, and the generated load model parameters of the grid-type energy storage system can be fully applied to the simulation calculation and planning and design of the power grid, so as to improve the accuracy of the simulation calculation of the power grid and provide more accurate simulation analysis results for the power grid analysis and decision-making.

[0210] Exemplary Devices

[0211] Figure 8 FIG. 1 is a schematic diagram of the structure of a device for establishing a substation load model according to a preferred embodiment of the present invention. Figure 8 As shown, the device 800 for establishing a substation load model in this preferred embodiment includes:

[0212] Data acquisition module 801, used to collect grid-type energy storage system data, static load equipment data, induction motor data and substation sending end data in the power distribution area of ​​the substation;

[0213] A first model module 802 is used to calculate the aggregated equivalent parameters of the grid-type energy storage system according to the grid-type energy storage system data, and to establish an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system;

[0214] The second model module 803 is used to calculate the static load equivalent parameters of the power distribution area according to the static load equipment data, and establish a static load equivalent model based on the static load equivalent parameters;

[0215] The third model module 804 is used to calculate the dynamic load equivalent parameters of the power distribution area according to the induction motor data, and establish an equivalent dynamic load model based on the dynamic load equivalent parameters;

[0216] The fourth model module 805 is used to calculate the reactive compensation parameters of the power distribution area according to the grid-type energy storage system data, the induction motor data, the static load equipment data and the substation sending end data, and establish a reactive compensation model based on the reactive compensation parameters;

[0217] The load model module 806 is used to construct a comprehensive load model including a grid-type energy storage system based on the equivalent grid-type energy storage system model, the equivalent static load model, the equivalent dynamic load model and the reactive power compensation model.

[0218] Preferably, the data acquisition module 801 acquires grid-connected energy storage system data, induction motor data, static load equipment data and substation sending-end data in the power distribution area of ​​the substation, including:

[0219] Collect the rated capacity, maximum active output, maximum reactive output, actual active output, actual reactive output, connection reactance of N energy storage devices to the common connection point PCC, line reactance and transformer reactance of N energy storage devices in the grid-type energy storage system, as well as the transient time constant of the model of N energy storage devices, the time constant of the equivalent virtual synchronization module, virtual damping, the regulator gain of the equivalent virtual excitation control module, the proportional integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant, the synchronous reactance, and the d-axis transient reactance;

[0220] Collect the rated active power, rated reactive power and rated voltage of several static load devices in the substation, as well as the actual reactive output;

[0221] Collect the rated active power, rated reactive power, rated phase voltage, rated electromagnetic power, maximum electromagnetic power, kinetic energy, rotor winding copper loss and actually absorbed reactive power of several induction motors in the substation;

[0222] Collect reactive power at the sending end of the substation.

[0223] Preferably, the first model module 802 calculates the aggregated equivalent parameters of the grid-type energy storage system according to the grid-type energy storage system data, and establishes an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system, including:

[0224] The rated capacity, maximum active output, maximum reactive output, actual active output, and actual reactive output of N energy storage devices in the grid-type energy storage system are summed up to determine the equivalent rated capacity, equivalent maximum active output, equivalent maximum reactive output, equivalent actual active output, and equivalent actual reactive output of the grid-type energy storage system;

[0225] According to the connection reactance, line reactance and transformer reactance of N energy storage devices in the grid-type energy storage system to the common connection point PCC, the equivalent reactance is determined, and the calculation formula is:

[0226]

[0227] X′ C,n =X C,n +X L,n +X T,n

[0228] In the formula, X′ C,n , X C,n , X L,n and X T,n are the equivalent reactance, connection reactance, line reactance and transformer reactance of the nth grid-connected energy storage device connected to the PCC, respectively, and X C,EQ is the equivalent reactance of the grid-type energy storage system;

[0229] According to the virtual damping of the equivalent virtual synchronization module in the model of N energy storage devices in the grid-type energy storage system, the equivalent virtual damping of the grid-type energy storage system is determined, and the calculation formula is:

[0230]

[0231] Where D n is the virtual damping of the equivalent virtual synchronization module in the model of the nth grid-connected energy storage device, D EQ is the equivalent virtual damping of the grid-type energy storage system;

[0232] According to the maximum active output of the N energy storage devices in the grid-type energy storage system and the time constant of the equivalent virtual synchronization module of the corresponding device model, the time constant of the equivalent virtual synchronization module of the grid-type energy storage system is determined, and the calculation formula is:

[0233]

[0234] Where, T j,EQ is the time constant of the equivalent virtual synchronization module of the grid-connected energy storage system, P max,n is the maximum active output of the nth grid-connected energy storage device, T j,nis the time constant of the equivalent virtual synchronization module of the model of the nth grid-connected energy storage device;

[0235] According to the synchronous reactance and d-axis transient reactance of the models of N energy storage devices in the grid-type energy storage system, the equivalent synchronous reactance and equivalent d-axis transient reactance of the grid-type energy storage system are determined respectively, and the calculation formula is:

[0236]

[0237] Where, X d,n and X′ d,n are the equivalent synchronous reactance and equivalent d-axis transient reactance of the model of the nth grid-connected energy storage device, respectively, X d,EQ and X′ d,EQ are the equivalent synchronous reactance and the equivalent d-axis transient reactance of the grid-type energy storage system respectively;

[0238] According to the maximum active output of N energy storage devices in the grid-type energy storage system and the transient time constant of the corresponding device model, the proportional-integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant and the regulator gain of the equivalent virtual excitation control module, the equivalent transient time constant, the equivalent proportional-integral selection factor, the equivalent first voltage regulator time constant, the equivalent second voltage regulator time constant, the equivalent filter time constant and the regulator gain of the equivalent virtual excitation control module of the grid-type energy storage system are determined, and the calculation formulas are:

[0239]

[0240]

[0241] In the formula, Q max,n is the maximum active output of the nth energy storage device, T′ d0,n , k n , T 1,n , T 2,n , T R,n and k V,n are the transient time constant of the model of the nth energy storage device, the proportional integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant and the regulator gain of the equivalent virtual excitation control module, T′ d0,EQ , k EQ , T 1,EQ , T 2,EQ , T R,EQ and k V,EQThey are respectively the equivalent transient time constant, the equivalent proportional integral selection factor, the equivalent first voltage regulator time constant, the equivalent second voltage regulator time constant, the equivalent filter time constant and the equivalent regulator gain of the virtual excitation control module of the grid-type energy storage system;

[0242] An equivalent grid-type energy storage system model is established based on the equivalent rated capacity, equivalent maximum active output, equivalent maximum reactive output, equivalent actual active output, equivalent actual reactive output, equivalent reactance, equivalent virtual damping, equivalent synchronous reactance and equivalent d-axis transient reactance, equivalent transient time constant, equivalent proportional-integral selection factor, equivalent first voltage regulator time constant, equivalent second voltage regulator time constant, equivalent filter time constant and equivalent virtual excitation control module regulator gain of the grid-type energy storage system.

[0243] Preferably, the second model module 803 calculates the static load equivalent parameters of the power distribution area according to the static load equipment data, and establishes a static load equivalent model based on the static load equivalent parameters, including:

[0244] Based on the ZIP model principle of constant impedance, constant current and constant power, the static load equivalent parameters are determined according to the rated active power, rated reactive power and rated voltage of the static load equipment in the substation;

[0245] An equivalent static load model is established based on the equivalent parameters of static load.

[0246] Preferably, the third model module 804 calculates the dynamic load equivalent parameters of the power distribution area according to the induction motor data, and establishes an equivalent dynamic load model based on the dynamic load equivalent parameters, including:

[0247] According to the principle of keeping the total rated active power and reactive power absorbed by the load nodes in the power distribution area unchanged, the total electromagnetic power, maximum electromagnetic power and total kinetic energy unchanged, and the total rotor winding copper loss unchanged, the dynamic load equivalent parameters are calculated according to the rated active power, rated reactive power, rated phase voltage, rated electromagnetic power, maximum electromagnetic power, kinetic energy and rotor winding copper loss of the induction motor of the substation;

[0248] An equivalent dynamic load model is established based on the equivalent parameters of dynamic load.

[0249] Preferably, the fourth model module 805 calculates reactive compensation parameters of the power distribution area according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, and establishes a reactive compensation model based on the reactive compensation parameters, including:

[0250] Based on the reactive power balance principle, the reactive compensation parameters of the power distribution area are calculated according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, wherein the reactive compensation parameter calculation formula is:

[0251] -Q SC =Q-(Q IM +Q Z +Q I +Q P -Q EQ )

[0252] In the formula, Q SC is the reactive power compensation parameter of the power distribution area, Q is the reactive power at the sending end of the substation, and Q IM Q is the sum of reactive power actually absorbed by several induction motors in the substation. Z , Q I and Q P They are the sum of the actual reactive power outputs of all static constant impedance load devices in the substation, the sum of the actual reactive power outputs of all static constant current load devices in the substation, and the actual reactive power outputs of all static constant power load devices. EQ is the sum of the actual reactive power outputs of N grid-type energy storage devices in the grid-type energy storage system;

[0253] Based on the reactive power compensation parameter Q SC Establish reactive power compensation model.

[0254] The device for establishing a substation load model described in this preferred embodiment is aimed at a substation including a grid-type energy storage system composed of multiple grid-type energy storage devices. By collecting grid-type energy storage system data, static load equipment data, induction motor data and substation sending-end data in the power distribution area of ​​the substation, the aggregation equivalent parameters of the grid-type energy storage system, the static load equivalent parameters of the power distribution area, the dynamic load equivalent parameters and reactive compensation parameters are calculated respectively, so that the steps of establishing a comprehensive load model including an equivalent grid-type energy storage model are the same as the steps taken by the method for establishing a substation load model described in the present invention, and the technical effects achieved are also the same, which will not be repeated here.

[0255] Exemplary Electronic Devices

[0256] Fig. 9 The electronic device according to the preferred embodiment of the present invention is a schematic diagram of the structure of the electronic device. The electronic device can be any one or both of the first device and the second device, or a stand-alone device independent of them, and the stand-alone device can communicate with the first device and the second device to receive the collected input signal from them. Fig. 9 FIG. 1 is a block diagram of an electronic device according to an embodiment of the present disclosure. Fig. 9 As shown, the electronic device includes one or more processors 901 and a memory 902 .

[0257] The processor 901 may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0258] The memory 902 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 901 may run the program instructions to implement the energy consumption anomaly diagnosis method based on the enterprise energy consumption space of the various embodiments disclosed above and / or other desired functions. In one example, the electronic device may also include: an input device 903 and an output device 904, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0259] In addition, the input device 903 may also include, for example, a keyboard, a mouse, and the like.

[0260] The output device 904 can output various information to the outside, and can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto.

[0261] Of course, to simplify, Fig. 9 Only some of the components related to the present disclosure in the electronic device are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, according to specific application situations, the electronic device may further include any other appropriate components.

[0262] Exemplary computer program products and computer-readable storage media

[0263] In addition to the above-mentioned methods and devices, an embodiment of the present disclosure may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps in the method of establishing a substation load model according to various embodiments of the present disclosure described in the above-mentioned "Exemplary Method" section of this specification.

[0264] The computer program product may be written in any combination of one or more programming languages ​​to write program code for performing the operations of the disclosed embodiments, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0265] In addition, an embodiment of the present disclosure may also be a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, enables the processor to execute the steps in the method for establishing a substation load model according to various embodiments of the present disclosure described in the above “Exemplary Method” section of this specification.

[0266] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0267] The basic principles of the present disclosure are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present disclosure are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present disclosure. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, and are not limitations. The above details do not limit the present disclosure to the necessity of adopting the above specific details to be implemented.

[0268] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0269] The block diagrams of the devices, apparatuses, equipment, and systems involved in this disclosure are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including," "comprising," "having," and the like are open words, referring to "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or," and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0270] The apparatus and method of the present disclosure may be implemented in many ways. For example, the apparatus and method of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above order of steps for the method is for illustration only, and the steps of the method of the present disclosure are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present disclosure may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present disclosure. Therefore, the present disclosure also covers a recording medium storing a program for executing the method according to the present disclosure.

[0271] It should also be noted that in the apparatus, equipment and method of the present disclosure, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present disclosure. The above description of the disclosed aspects is provided to enable any technician in the field to make or use the present disclosure. Various modifications to these aspects are very obvious to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the aspects shown here, but to the widest scope consistent with the principles and novel features disclosed herein.

[0272] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present disclosure to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A method for establishing a substation load model, characterized in that: The method comprises: Collect grid-connected energy storage system data, static load equipment data, induction motor data and substation sending-end data in the substation power distribution area; According to the grid-type energy storage system data, calculating the aggregated equivalent parameters of the grid-type energy storage system, and establishing an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system; Calculating static load equivalent parameters of the power distribution area according to the static load equipment data, and establishing a static load equivalent model based on the static load equivalent parameters; Calculating the dynamic load equivalent parameters of the power distribution area according to the induction motor data, and establishing an equivalent dynamic load model based on the dynamic load equivalent parameters; Calculate reactive power compensation parameters of the power distribution area according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, and establish a reactive power compensation model based on the reactive power compensation parameters; A comprehensive load model including a grid-type energy storage system is constructed based on the equivalent grid-type energy storage system model, the equivalent static load model, the equivalent dynamic load model and the reactive power compensation model.

2. The method according to claim 1, characterized in that The data of the grid-connected energy storage system, induction motor data, static load equipment data and substation sending-end data collected in the power distribution area of ​​the substation include: Collect the rated capacity, maximum active output, maximum reactive output, actual active output, actual reactive output, connection reactance of N energy storage devices to the common connection point PCC, line reactance and transformer reactance of N energy storage devices in the grid-type energy storage system, as well as the transient time constant of the model of N energy storage devices, the time constant of the equivalent virtual synchronization module, virtual damping, the regulator gain of the equivalent virtual excitation control module, the proportional integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant, the synchronous reactance, and the d-axis transient reactance; Collect the rated active power, rated reactive power and rated voltage of several static load devices in the substation, as well as the actual reactive output; Collect the rated active power, rated reactive power, rated phase voltage, rated electromagnetic power, maximum electromagnetic power, kinetic energy, rotor winding copper loss and actually absorbed reactive power of several induction motors in the substation; Collect reactive power at the sending end of the substation.

3. The method according to claim 2, characterized in that The method of calculating the aggregated equivalent parameters of the grid-type energy storage system according to the grid-type energy storage system data, and establishing an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system, includes: The rated capacity, maximum active output, maximum reactive output, actual active output, and actual reactive output of N energy storage devices in the grid-type energy storage system are summed up to determine the equivalent rated capacity, equivalent maximum active output, equivalent maximum reactive output, equivalent actual active output, and equivalent actual reactive output of the grid-type energy storage system; According to the connection reactance, line reactance and transformer reactance of N energy storage devices in the grid-type energy storage system to the common connection point PCC, the equivalent reactance is determined, and the calculation formula is: X′ C,n =X C,n +X L,n +X T,n In the formula, X′ C,n , X C,n , X L,n and X T,n are the equivalent reactance, connection reactance, line reactance and transformer reactance of the nth grid-connected energy storage device connected to the PCC, respectively, and X C,EQ is the equivalent reactance of the grid-type energy storage system; According to the virtual damping of the equivalent virtual synchronization module in the model of N energy storage devices in the grid-type energy storage system, the equivalent virtual damping of the grid-type energy storage system is determined, and the calculation formula is: Where D n is the virtual damping of the equivalent virtual synchronization module in the model of the nth grid-connected energy storage device, D EQ is the equivalent virtual damping of the grid-type energy storage system; According to the maximum active output of the N energy storage devices in the grid-type energy storage system and the time constant of the equivalent virtual synchronization module of the corresponding device model, the time constant of the equivalent virtual synchronization module of the grid-type energy storage system is determined, and the calculation formula is: Where, T j,EQ is the time constant of the equivalent virtual synchronization module of the grid-connected energy storage system, P max,n is the maximum active output of the nth grid-connected energy storage device, T j,n is the time constant of the equivalent virtual synchronization module of the model of the nth grid-connected energy storage device; According to the synchronous reactance and d-axis transient reactance of the models of N energy storage devices in the grid-type energy storage system, the equivalent synchronous reactance and equivalent d-axis transient reactance of the grid-type energy storage system are determined respectively, and the calculation formula is: Where, X d,n and X′ d,n are the equivalent synchronous reactance and equivalent d-axis transient reactance of the model of the nth grid-connected energy storage device, respectively, X d,EQ and X′ d,EQ are the equivalent synchronous reactance and the equivalent d-axis transient reactance of the grid-type energy storage system respectively; According to the maximum active output of N energy storage devices in the grid-type energy storage system and the transient time constant of the corresponding device model, the proportional-integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant and the regulator gain of the equivalent virtual excitation control module, the equivalent transient time constant, the equivalent proportional-integral selection factor, the equivalent first voltage regulator time constant, the equivalent second voltage regulator time constant, the equivalent filter time constant and the regulator gain of the equivalent virtual excitation control module of the grid-type energy storage system are determined, and the calculation formulas are: In the formula, Q max,n is the maximum active output of the nth energy storage device, T′ d0,n , k n , T 1,n , T 2,n , T R,n and k V,n are the transient time constant of the model of the nth energy storage device, the proportional integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant and the regulator gain of the equivalent virtual excitation control module, T′ d0,EQ , k EQ , T 1,EQ , T 2,EQ , T R,EQ and k V,EQ They are respectively the equivalent transient time constant, the equivalent proportional integral selection factor, the equivalent first voltage regulator time constant, the equivalent second voltage regulator time constant, the equivalent filter time constant and the equivalent regulator gain of the virtual excitation control module of the grid-type energy storage system; An equivalent grid-type energy storage system model is established based on the equivalent rated capacity, equivalent maximum active output, equivalent maximum reactive output, equivalent actual active output, equivalent actual reactive output, equivalent reactance, equivalent virtual damping, equivalent synchronous reactance and equivalent d-axis transient reactance, equivalent transient time constant, equivalent proportional-integral selection factor, equivalent first voltage regulator time constant, equivalent second voltage regulator time constant, equivalent filter time constant and equivalent virtual excitation control module regulator gain of the grid-type energy storage system.

4. The method according to claim 2, characterized in that: The step of calculating the static load equivalent parameters of the power distribution area according to the static load equipment data, and establishing a static load equivalent model based on the static load equivalent parameters includes: Based on the ZIP model principle of constant impedance, constant current and constant power, the static load equivalent parameters are determined according to the rated active power, rated reactive power and rated voltage of the static load equipment in the substation; An equivalent static load model is established based on the equivalent parameters of static load.

5. The method according to claim 2, characterized in that: The step of calculating the dynamic load equivalent parameters of the power distribution area according to the induction motor data, and establishing an equivalent dynamic load model based on the dynamic load equivalent parameters includes: According to the principle of keeping the total rated active power and reactive power absorbed by the load nodes in the power distribution area unchanged, the total electromagnetic power, maximum electromagnetic power and total kinetic energy unchanged, and the total rotor winding copper loss unchanged, the dynamic load equivalent parameters are calculated according to the rated active power, rated reactive power, rated phase voltage, rated electromagnetic power, maximum electromagnetic power, kinetic energy and rotor winding copper loss of the induction motor of the substation; An equivalent dynamic load model is established based on the equivalent parameters of dynamic load.

6. The method according to claim 2, characterized in that The method of calculating reactive compensation parameters of the power distribution area according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, and establishing a reactive compensation model based on the reactive compensation parameters includes: Based on the reactive power balance principle, the reactive compensation parameters of the power distribution area are calculated according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, wherein the reactive compensation parameter calculation formula is: -Q SC =Q-(Q IM +Q Z +Q I +Q P -Q EQ ) In the formula, Q SC is the reactive power compensation parameter of the power distribution area, Q is the reactive power at the sending end of the substation, and Q IM Q is the sum of reactive power actually absorbed by several induction motors in the substation. Z , Q I and Q P They are the sum of the actual reactive power outputs of all static constant impedance load devices in the substation, the sum of the actual reactive power outputs of all static constant current load devices in the substation, and the actual reactive power outputs of all static constant power load devices. EQ is the sum of the actual reactive power outputs of N grid-type energy storage devices in the grid-type energy storage system; Based on the reactive power compensation parameter Q SC Establish reactive power compensation model.

7. A device for establishing a substation load model, characterized in that: The device comprises: Data acquisition module, used to collect grid-type energy storage system data, static load equipment data, induction motor data and substation sending end data in the power distribution area of ​​the substation; A first model module is used to calculate the aggregated equivalent parameters of the grid-type energy storage system according to the grid-type energy storage system data, and to establish an equivalent grid-type energy storage system model based on the aggregated equivalent parameters of the grid-type energy storage system; A second model module is used to calculate the static load equivalent parameters of the power distribution area according to the static load equipment data, and establish a static load equivalent model based on the static load equivalent parameters; A third model module is used to calculate the dynamic load equivalent parameters of the power distribution area according to the induction motor data, and establish an equivalent dynamic load model based on the dynamic load equivalent parameters; A fourth model module is used to calculate reactive compensation parameters of the power distribution area according to the grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data, and establish a reactive compensation model based on the reactive compensation parameters; The load model module is used to construct a comprehensive load model including a grid-type energy storage system based on the equivalent grid-type energy storage system model, the equivalent static load model, the equivalent dynamic load model and the reactive power compensation model.

8. The device according to claim 7, characterized in that The data acquisition module collects grid-type energy storage system data, induction motor data, static load equipment data and substation sending end data in the power distribution area of ​​the substation, including: Collect the rated capacity, maximum active output, maximum reactive output, actual active output, actual reactive output, connection reactance of N energy storage devices to the common connection point PCC, line reactance and transformer reactance of N energy storage devices in the grid-type energy storage system, as well as the transient time constant of the model of N energy storage devices, the time constant of the equivalent virtual synchronization module, virtual damping, the regulator gain of the equivalent virtual excitation control module, the proportional integral selection factor, the time constant of the first voltage regulator and the second voltage regulator, the filter time constant, the synchronous reactance, and the d-axis transient reactance; Collect the rated active power, rated reactive power and rated voltage of several static load devices in the substation, as well as the actual reactive output; Collect the rated active power, rated reactive power, rated phase voltage, rated electromagnetic power, maximum electromagnetic power, kinetic energy, rotor winding copper loss and actually absorbed reactive power of several induction motors in the substation; Collect reactive power at the sending end of the substation.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1 to 6.

10. An electronic device, characterized in that: The electronic device comprises: processor; a memory for storing instructions executable by the processor; The processor is used to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1 to 6.

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