Low-frequency load shedding control method and system for inertia supporting capacity of network construction type equipment

Abstract

The invention discloses a low-frequency load shedding control method and a low-frequency load shedding control system for inertia supporting capability of network construction type equipment, and belongs to the technical field of power systems. The method comprises the following steps: acquiring operation state data of a power system, and calculating a support capability index of network construction type equipment based on the operation state data; based on the supporting capacity index, performing dynamic calculation of low-frequency load shedding multi-round threshold values to judge whether low-frequency load shedding control is executed or not; and if so, performing dynamic adjustment on the virtual inertia parameter, and judging whether to quit the low-frequency load shedding control or not based on the real-time frequency and the frequency deviation rate. According to the invention, a high-reliability and high-economy frequency stability control solution is provided for a novel power system.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and more particularly, to a low-frequency load shedding control method and system for the inertia support capability of network-forming devices. Background Art

[0002] After a large amount of new energy is incorporated into the power grid, the inertia of the power grid system decreases, and it is easy for over-cutting to occur in low-frequency load shedding measures after extremely severe faults occur. With the wide application of grid-forming converters (GFMs) in new energy power stations such as wind power and photovoltaic power, they gradually replace traditional synchronous generators and become the core main body for power grid frequency regulation. Currently, network-forming devices have evolved from the early single passive support mode to an active control unit with virtual inertia, dynamic frequency modulation, and fast power response, and are widely used in microgrids, new energy bases, and weak grid scenarios.

[0003] However, existing low-frequency load shedding schemes still follow the static threshold framework in the era dominated by synchronous machines, resulting in the disconnection between the control logic and the device characteristics:

[0004] On the one hand, although network-forming devices can dynamically adjust virtual inertia to enhance system stability, their non-linear response characteristics are not included in the low-frequency load shedding threshold calculation model;

[0005] On the other hand, the distributed deployment mode of network-forming devices conflicts with traditional centralized load shedding strategies, and it is easy to cause local overload and imbalance of global regulation capabilities.

[0006] This contradiction is particularly prominent in high-new energy proportion systems. When the system inertia mainly depends on network-forming devices, traditional schemes cannot sense the dynamic changes of virtual inertia, and the load shedding action lags behind the actual frequency drop rate or cuts off the load prematurely, resulting in economic losses. New ideas are needed to design low-frequency load shedding schemes to adapt to high-new energy proportion power grids. Summary of the Invention

[0007] In view of the above problems, the present invention proposes a low-frequency load shedding control method for the inertia support capability of network-forming devices, including:

[0008] Collect the operation status data of the power system, and calculate the support capability index of the network-forming device based on the operation status data;

[0009] Based on the support capability index, perform dynamic calculation of the low-frequency load shedding multi-round thresholds to determine whether to execute low-frequency load shedding control;

[0010] If executed, dynamically adjust the virtual inertia parameter, and determine whether to exit the low-frequency load shedding control based on the real-time frequency and the frequency deviation rate.

[0011] Optionally, the operation status data includes:

[0012] The capacity of all network-forming devices and synchronous generators in the power grid.

[0013] Optionally, the calculation formula for the support capacity index of network-forming devices is as follows:

[0014]

[0015] Where η sup port is the support capacity index, is the equivalent virtual inertia time constant of network-forming devices, is the equivalent inertia time constant of synchronous generators, S GFM is the sum of the capacities of all network-forming devices, S GEN is the sum of the capacities of all synchronous generators, and m and n are the numbers of synchronous generators and network-forming devices respectively.

[0016] Optionally, based on the support capacity index, dynamic calculation of the low-frequency load shedding multi-round thresholds is performed, including:

[0017] Initialize the basic frequency threshold for low-frequency load shedding rounds k is the low-frequency load shedding round, and decreases gradually with the round;

[0018] According to the support capacity of the converter, dynamically adjust the low-frequency load shedding trigger threshold, and the thresholds for each round are:

[0019]

[0020] Where γ (k) is the proportionality coefficient for the k-th round.

[0021] Optionally, determine whether to execute low-frequency load shedding control, including:

[0022] When the system frequency and continuously exceeds the action delay T delay , trigger the k-th round of low-frequency load shedding and take load shedding control.

[0023] Optionally, perform dynamic adjustment for virtual inertia parameters, including:

[0024] After each round of low-frequency load shedding is triggered, according to the current load shedding amount and the system frequency deviation, dynamically adjust the virtual inertia parameter H v , and the calculation formula is as follows:

[0025]

[0026] Where H base is the initial virtual inertia time constant of network-forming equipment, f 0is the rated frequency of the power grid, f(t) is the real-time frequency of the power grid, and P shed-i is the load shedding amount in the i-th round, and P shed is the total load shedding amount; α is the frequency deviation weight coefficient; β is the load shedding amount weight coefficient.

[0027] Optionally, determining whether to exit the low-frequency load shedding control includes:

[0028] In the frequency recovery stage, determine whether the real-time frequency and the frequency deviation rate meet the criteria. If they meet, exit the low-frequency load shedding control. If they do not meet, wait for the next round of low-frequency load shedding action. The criteria are as follows:

[0029]

[0030] After exiting the low-frequency load shedding control, gradually reduce the virtual inertia parameter H of the network-forming equipment v until it returns to the initial value H base ;

[0031] where f Hth is the low-frequency load shedding exit frequency threshold, and ε Hth is the low-frequency load shedding exit frequency change rate threshold.

[0032] On the other hand, the present invention also provides a low-frequency load shedding control system for the inertia support ability of network-forming equipment, including:

[0033] A calculation unit for collecting the operation state data of the power system and calculating the support ability index of the network-forming equipment based on the operation state data;

[0034] A first execution unit for dynamically calculating the thresholds of multiple rounds of low-frequency load shedding based on the support ability index to determine whether to execute low-frequency load shedding control;

[0035] A second execution unit for, if executed, dynamically adjusting the virtual inertia parameter and determining whether to exit the low-frequency load shedding control based on the real-time frequency and the frequency deviation rate.

[0036] Optionally, the operation state data includes:

[0037] The capacities of all network-forming equipment and synchronous generators in the power grid.

[0038] Optionally, the calculation formula for calculating the support ability index of the network-forming equipment is as follows:

[0039]

[0040] where η sup port is the support ability index, is the equivalent virtual inertia time constant of the network-forming equipment, is the equivalent inertia time constant of the synchronous generator, S GFM is the sum of the capacities of all network-forming devices, S GEN is the sum of the capacities of all synchronous generators, where m and n are the numbers of synchronous generators and network-forming devices respectively.

[0041] Optionally, based on the support capacity index, perform dynamic calculation of the multi-round thresholds of under-frequency load shedding, including:

[0042] Initialize the basic frequency threshold for under-frequency load shedding rounds k is the under-frequency load shedding round, and decreases step by step with the round.

[0043] According to the support capacity of the converter, dynamically adjust the under-frequency load shedding trigger threshold, and the thresholds for each round are:

[0044]

[0045] where γ (k) is the proportionality coefficient for the k-th round.

[0046] Optionally, determine whether to execute under-frequency load shedding control, including:

[0047] When the system frequency and continuously exceeds the action delay T delay , trigger the k-th round of under-frequency load shedding and take load shedding control.

[0048] Optionally, perform dynamic adjustment for the virtual inertia parameter, including:

[0049] After each round of under-frequency load shedding is triggered, according to the current load shedding amount and the system frequency deviation, dynamically adjust the virtual inertia parameter H v , and the calculation formula is as follows:

[0050]

[0051] where J base is the initial virtual inertia time constant of the network-forming equipment, f 0 is the rated grid frequency, f(t) is the real-time grid frequency, P shed-i is the load shedding amount for the i-th round, P shed is the total load shedding amount; α is the frequency deviation weight coefficient; β is the load shedding amount weight coefficient.

[0052] Optionally, determine whether to exit the under-frequency load shedding control, including:

[0053] In the frequency recovery stage, determine whether the real-time frequency and the frequency deviation rate meet the criterion. If they meet, exit the under-frequency load shedding control. If they do not meet, wait for the next round of under-frequency load shedding action. The criterion is as follows:

[0054]

[0055] After exiting the low-frequency load shedding control, gradually reduce the virtual inertia parameter H of the network-forming equipment v until it returns to the initial value H base ;

[0056] where f Hth is the low-frequency load shedding exit frequency threshold, and ε Hth is the low-frequency load shedding exit frequency change rate threshold.

[0057] On the other hand, the present invention also provides a computing device, including: one or more processors;

[0058] The processor is used to execute one or more programs;

[0059] When the one or more programs are executed by the one or more processors, the method as described above is implemented.

[0060] On the other hand, the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed, the method as described above is implemented.

[0061] Compared with the prior art, the beneficial effects of the present invention are:

[0062] The present invention provides a low-frequency load shedding control method for the inertia support ability of network-forming equipment, including: collecting the operation state data of the power system, calculating the support ability index of the network-forming equipment based on the operation state data; dynamically calculating the thresholds of multiple rounds of low-frequency load shedding based on the support ability index to determine whether to execute low-frequency load shedding control; if executed, dynamically adjust the virtual inertia parameter, and determine whether to exit the low-frequency load shedding control based on the real-time frequency and the frequency deviation rate. The present invention provides a frequency stability control solution with high reliability and high economy for the new power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 is a flowchart of the method of the present invention;

[0064] Figure 2 is a flowchart of an embodiment of the method of the present invention;

[0065] Figure 3 is a control effect diagram of the method of the present invention;

[0066] Figure 4 is a structure diagram of the system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0067] Reference is now made to the accompanying drawings to describe exemplary embodiments of the present invention. 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 in the exemplary embodiments shown in the drawings are not limitations on the present invention. In the drawings, the same units / components are denoted by the same reference numerals.

[0068] Unless otherwise specified, the terms used herein (including scientific and technical terms) have the ordinary meaning understood by those skilled in the art. In addition, it can be understood that the terms defined in the commonly used dictionary should be understood as having a meaning consistent with the context of their relevant fields, and should not be understood as having an idealized or overly formal meaning.

[0069] Embodiment 1:

[0070] The present invention proposes a low-frequency load shedding control method for the inertia support capacity of network-forming devices, as Figure 1 shown, including:

[0071] Step 1, collect the operation state data of the power system, and calculate the support capacity index of the network-forming devices based on the operation state data;

[0072] Step 2, based on the support capacity index, perform dynamic calculation of the low-frequency load shedding multi-round thresholds to determine whether to execute the low-frequency load shedding control;

[0073] Step 3, if executed, dynamically adjust the virtual inertia parameters, and determine whether to exit the low-frequency load shedding control based on the real-time frequency and frequency deviation rate.

[0074] Among them, the operation state data includes:

[0075] The capacities of all network-forming devices and synchronous generators in the power grid.

[0076] Among them, the calculation formula for calculating the support capacity index of the network-forming devices is as follows:

[0077]

[0078]

[0079] Among them, η sup port is the support capacity index, is the equivalent virtual inertia time constant of the network-forming device, is the equivalent inertia time constant of the synchronous generator, S GFM is the sum of the capacities of all network-forming devices, S GENis the sum of the capacities of all synchronous generators, where m and n are the numbers of synchronous generators and network-forming devices respectively.

[0080] Among them, based on the support capacity index, the dynamic calculation of the low-frequency load shedding multi-round thresholds includes:

[0081] Initializing the basic frequency threshold for low-frequency load shedding rounds k is the low-frequency load shedding round, and decreases step by step with the round.

[0082] According to the support capacity of the converter, dynamically adjust the low-frequency load shedding trigger threshold, and the thresholds for each round are:

[0083]

[0084] Among them, γ (k) is the proportionality coefficient for the k-th round.

[0085] Among them, judging whether to execute the low-frequency load shedding control includes:

[0086] When the system frequency and continuously exceeds the action delay T delay , trigger the k-th round of low-frequency load shedding and take load shedding control.

[0087] Among them, dynamically adjusting the virtual inertia parameter includes:

[0088] After each round of low-frequency load shedding is triggered, according to the current load shedding amount and the system frequency deviation, dynamically adjust the virtual inertia parameter H v , and the calculation formula is as follows:

[0089]

[0090] Among them, H base is the initial virtual inertia time constant of the network-forming equipment, f 0 is the rated grid frequency, f(t) is the real-time grid frequency, P shed-i is the load shedding amount in the i-th round, P shed is the total load shedding amount; α is the frequency deviation weight coefficient; β is the load shedding amount weight coefficient.

[0091] Among them, judging whether to exit the low-frequency load shedding control includes:

[0092] In the frequency recovery stage, judge whether the real-time frequency and the frequency deviation rate meet the criterion. If they meet, exit the low-frequency load shedding control. If they do not meet, wait for the next round of low-frequency load shedding action. The criterion is as follows:

[0093]

[0094] After exiting the low-frequency load shedding control, gradually reduce the virtual inertia parameter H of the network-forming equipment v until it returns to the initial value H base ;

[0095] where f Hth is the low-frequency load shedding exit frequency threshold, and ε Hth is the low-frequency load shedding exit frequency change rate threshold.

[0096] The present invention will be further described below in conjunction with specific examples and calculation examples:

[0097] The steps of the example are as Figure 2 shown and include:

[0098] (1) Collect the system operation status:

[0099] (1-1) Real-time monitor the system frequency f(t) and the frequency change rate

[0100] (1-2) Obtain the current load shedding amount P shed_i ;

[0101] (1-3) Collect the capacities of all network-forming equipment and synchronous generators in the power grid, and calculate the support capacity index η of the network-forming equipment support .

[0102]

[0103] T j GFM is the equivalent virtual inertia time constant of the network-forming equipment, T j GFM is the equivalent inertia time constant of the synchronous generator, S GFM is the sum of the capacities of all network-forming equipment, S GEN is the sum of the capacities of all synchronous generators, and m and n are the numbers of synchronous generators and network-forming equipment respectively.

[0104] (2) Dynamic calculation of the multi-round threshold of low-frequency load shedding:

[0105] (2-1) Initialize the basic frequency threshold of the low-frequency load shedding rounds k is the low-frequency load shedding round, which decreases step by step with the round.

[0106] (2-2) Dynamically adjust the low-frequency load shedding trigger threshold according to the support capacity of the converter. The thresholds for each round are:

[0107]

[0108] where γ (k)is the proportionality coefficient for the k-th round, and this parameter can be obtained by simulating and testing the system frequency response under different network-forming device capacities.

[0109] (3) Determine whether to execute load shedding under low frequency:

[0110] Judge whether to start load shedding under low frequency according to the grid frequency. When the system frequency and continues to exceed the action delay T delay , trigger the k-th round of load shedding under low frequency and adopt load shedding control.

[0111] (4) Dynamic adjustment of virtual inertia parameters:

[0112] After each round of load shedding under low frequency is triggered, according to the current load shedding amount and the system frequency deviation, dynamically adjust the virtual inertia parameter H v in real time, and its calculation method is as follows:

[0113]

[0114] where H base is the initial virtual inertia time constant of the network-forming equipment; f 0 is the rated grid frequency, f(t) is the real-time grid frequency, and the greater the frequency deviation, the greater the virtual inertia increment; P shed-i is the load shedding amount in the i-th round, and the greater the load shedding amount, the greater the virtual inertia increment; P shed is the total load shedding amount; α is the frequency deviation weight coefficient; β is the load shedding amount weight coefficient.

[0115] (5) Judge whether to exit the load shedding control under low frequency:

[0116] (5-1) In the frequency recovery stage, judge whether the real-time frequency and the frequency deviation rate satisfy the following criterion. If satisfied, exit the load shedding control under low frequency. If not satisfied, wait for the next round of load shedding action.

[0117]

[0118] (5-2) After exiting the load shedding control under low frequency, gradually reduce the virtual inertia parameter H v of the network-forming equipment until it returns to the initial value H base .

[0119] The collaborative control method of network-forming equipment and load shedding under low frequency proposed by the present invention significantly improves the frequency stability and economic operation level of a high-proportion new energy power system through constructing a "dynamic threshold - virtual inertia" collaborative control architecture, and the control effect, such as Figure 3As shown in the figure, based on the dynamic correction of the support capacity index of network-forming equipment, the multi-round thresholds of under-frequency load shedding are accurately matched with the inertia regulation potential of network-forming equipment. According to the frequency drop and the cumulative load shedding amount, the virtual inertia is enhanced synchronously, so that the load shedding amount is reduced compared with the traditional scheme, providing a frequency stability control solution with high reliability and high economy for the new power system.

[0120] The specific calculation example is as follows:

[0121] (1) Collect the system operation status:

[0122] Taking a microgrid in a certain province as an example, the new energy penetration rate of the regional power grid reaches 40%, including: 10 network-forming wind power converters of 2.5 MW, and the virtual inertia time constant T j GFM-i = 5 s; 6 network-forming energy storage systems of 4 MWh, and the virtual inertia time constant T j GFM -i = 4.5 s; 2 synchronous generators of 100 MW, and the equivalent inertia time constant T j GEN-i = 4.8 s.

[0123] Use the synchronous phasor measurement unit to monitor the system frequency f(t) in real time, with a sampling period of 10 ms; obtain the capacity of each network-forming equipment through the wide-area measurement system (S GFM = 10×2.5 + 6×4 = 49 MW), the capacity of the synchronous generator (S GEN = 2×100 = 200 MW); the system rated frequency f 0 is 50 Hz; the total load shedding amount is 75 MW.

[0124] Calculate the support capacity index η sup port using formula (1-3):

[0125]

[0126] (2) Dynamic threshold calculation:

[0127] Set the initial threshold of under-frequency load shedding. The under-frequency load shedding includes 5 rounds, and the thresholds of each round are respectively

[0128]

[0129] According to the support capacity index η sup port Calculate the dynamically corrected threshold, and determine the proportionality coefficient γ (k) to be 0.5, 0.4, 0.3, 0.2, 0.1 respectively. From this, the under-frequency load shedding of each round is calculated as follows:

[0130]

[0131]

[0132] (3) Low-frequency load shedding execution:

[0133] Fault simulation: A wind farm suddenly trips off the grid (losing 20 MW), and the system frequency drops at a rate of -1.2 Hz / s. When the frequency is lower than 49.305 Hz and the duration exceeds 1.5 s, the first round of low-frequency load shedding operates, and 15 MW of load is shed.

[0134] (4) Virtual inertia dynamic adjustment:

[0135] Calculate the real-time increment of the virtual inertia of the grid-forming equipment according to formula (5), with the frequency deviation weight coefficient α = 0.2; the load shedding amount weight coefficient β = 0.5.

[0136] ΔH v (t) = 0.2×|50 - 49.305| + 0.5×0.2 = 0.239 s

[0137] The total virtual inertia is updated to:

[0138] H v (t) = H base +ΔH v (t) = 4.5 + 0.239 = 4.739 s

[0139] Increase the virtual inertia of the grid-forming equipment from 4.5 s to 4.739 s to enhance the frequency support ability.

[0140] (5) Determine whether to exit the low-frequency load shedding control:

[0141] After shedding 15 MW of load, it is detected that the system real-time frequency f(t) ≥ 49.8 Hz; the frequency deviation rate lasts for 1 s, and the low-frequency load shedding control is exited. The virtual inertia time constant of the grid-forming equipment returns to the initial value according to the exponential curve H v (t) = H v0 +ΔH v (t)·e -tτ (τ = 30 s). The frequency curves of the traditional low-frequency load shedding and the system of this invention patent are as Figure 2 shown. After the fault occurs, the first-round threshold is dynamically increased to 49.305 Hz (original 49.2 Hz) according to the real-time calculated η sup port , and the load is shed in advance; the virtual inertia time constant enhancement formula H v = 4.5 + 0.239 = 4.739 s is synchronously activated to reduce the frequency drop rate. The lowest frequency point is increased by 0.15 Hz, and the load loss is reduced by 18 MW.

[0142] Example 2:

[0143] On the other hand, the present invention also provides a low-frequency load shedding control system 200 for the inertia support ability of network-forming devices, as Figure 4 shown, including:

[0144] A calculation unit 201, configured to collect the operation state data of the power system, and calculate the support ability index of the network-forming device based on the operation state data;

[0145] A first execution unit 202, configured to dynamically calculate the thresholds of multiple rounds of low-frequency load shedding based on the support ability index to determine whether to execute low-frequency load shedding control;

[0146] A second execution unit 203, configured to, if executed, dynamically adjust the virtual inertia parameter, and determine whether to exit the low-frequency load shedding control based on the real-time frequency and the frequency deviation rate.

[0147] Among them, the operation state data includes:

[0148] The capacities of all network-forming devices and synchronous generators in the power grid.

[0149] Among them, the calculation formula for calculating the support ability index of the network-forming device is as follows:

[0150]

[0151] Among them, η sup port is the support ability index, is the equivalent virtual inertia time constant of the network-forming device, is the equivalent inertia time constant of the synchronous generator, S GFM is the sum of the capacities of all network-forming devices, S GEN is the sum of the capacities of all synchronous generators, and m and n are the numbers of synchronous generators and network-forming devices respectively.

[0152] Among them, dynamically calculating the thresholds of multiple rounds of low-frequency load shedding based on the support ability index includes:

[0153] Initializing the basic frequency threshold of the low-frequency load shedding rounds k is the low-frequency load shedding round, and is gradually reduced with the round;

[0154] According to the support ability of the converter, dynamically adjust the low-frequency load shedding trigger threshold, and the thresholds of each round are:

[0155]

[0156] Among them, γ (k) is the proportionality coefficient of the kth round.

[0157] Among them, determining whether to execute low-frequency load shedding control includes:

[0158] When the system frequency and continuously exceeds the action delay T delay trigger the kth round of low-frequency load shedding and adopt load shedding control.

[0159] Among them, dynamically adjusting the virtual inertia parameter includes:

[0160] After each round of low-frequency load shedding is triggered, according to the current load shedding amount and the system frequency deviation, dynamically adjust the virtual inertia parameter H in real time v , and the calculation formula is as follows:

[0161]

[0162] Among them, H base is the initial virtual inertia time constant of the network-forming equipment, f 0 is the rated grid frequency, f(t) is the real-time grid frequency, P shed-i is the load shedding amount in the i-th round, P shed is the total load shedding amount; α is the frequency deviation weight coefficient; β is the load shedding amount weight coefficient.

[0163] Among them, determining whether to exit the low-frequency load shedding control includes:

[0164] In the frequency recovery stage, determine whether the real-time frequency and the frequency deviation rate meet the criteria. If they meet, exit the low-frequency load shedding control. If they do not meet, wait for the next round of low-frequency load shedding action. The criteria are as follows:

[0165]

[0166] After exiting the low-frequency load shedding control, gradually reduce the virtual inertia parameter H of the network-forming equipment v , until it is restored to the initial value H base ;

[0167] Among them, f Hth is the low-frequency load shedding exit frequency threshold, and ε Hth is the low-frequency load shedding exit frequency change rate threshold.

[0168] The present invention provides a frequency stability control solution with high reliability and high economy for a new power system.

[0169] Example 3:

[0170] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory. The memory is used to store a computer program, and the computer program includes program instructions. The processor is used to execute the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of the method in the above embodiments.

[0171] Embodiment 4:

[0172] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory). The computer-readable storage medium is a memory device in the computer device and is used to store programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and, of course, the extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, and the operating system of the terminal is stored in this storage space. And, one or more instructions suitable for being loaded and executed by the processor are also stored in this storage space. These instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The one or more instructions stored in the computer-readable storage medium can be loaded and executed by the processor to implement the steps of the method in the above embodiments.

[0173] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The solutions in the embodiments of the present invention can be implemented in various computer languages. For example, object-oriented programming languages such as Java and interpreted scripting languages such as JavaScript, etc.

[0174] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for realizing the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 block or multiple blocks.

[0175] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means realizes the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 block or multiple blocks.

[0176] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for realizing the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 block or multiple blocks.

[0177] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concepts. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0178] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A low-frequency load reduction control method for the inertia support capacity of a network-type equipment, characterized in that: include: Collecting operation status data of the power system, and calculating the support capacity index of the network-building equipment based on the operation status data; Based on the support capacity index, dynamically calculate the threshold of multiple rounds of under-frequency load shedding to determine whether to perform under-frequency load shedding control; If executed, the virtual inertia parameters are dynamically adjusted, and based on the real-time frequency and frequency deviation rate, it is determined whether to exit the low-frequency load reduction control.

2. The low-frequency load reduction control method according to claim 1, characterized in that: The operating status data includes: The capacity of all grid-forming equipment and synchronous generators in the power grid.

3. The low-frequency load reduction control method according to claim 1, characterized in that: The calculation formula for calculating the support capability index of the networking device is as follows: Among them, η sup port is the support capacity index, is the equivalent virtual inertia time constant of the networked device, is the equivalent inertia time constant of the synchronous generator, S GFM is the sum of the capacities of all networking devices, S GEN is the sum of the capacities of all synchronous generators, m and n are the numbers of synchronous generators and grid-connecting equipment respectively.

4. The low-frequency load reduction control method according to claim 1, characterized in that: The dynamically calculating the multiple rounds of low-frequency load shedding thresholds based on the support capacity index includes: Initialize the basic frequency threshold of the low-frequency load shedding round k is the low frequency load shedding round, It decreases gradually with each round; According to the supporting capacity of the converter, the low-frequency load shedding trigger threshold is dynamically adjusted. The threshold for each round is: Among them, γ (k) is the k-th round proportional coefficient.

5. The low-frequency load reduction control method according to claim 1, characterized in that: The determining whether to perform low-frequency load reduction control includes: When the system frequency And it continues to exceed the action delay T delay When , the kth round of low-frequency load reduction is triggered and load shedding control is adopted.

6. The low-frequency load reduction control method according to claim 1, characterized in that: The dynamic adjustment of the virtual inertia parameters includes: After each round of low-frequency load shedding is triggered, the virtual inertia parameter H is adjusted dynamically in real time according to the current load shedding amount and system frequency deviation. v , the calculation formula is as follows: Among them, H base is the initial virtual inertia time constant of the grid-forming equipment, f0 is the rated frequency of the grid, f(t) is the real-time frequency of the grid, P shed-i is the load shedding amount in the i-th round, P shed is the total load shedding amount; α is the frequency deviation weight coefficient; β is the load shedding weight coefficient.

7. The low-frequency load reduction control method according to claim 1, characterized in that: The determining whether to exit the low-frequency load reduction control includes: In the frequency recovery phase, determine whether the real-time frequency and frequency deviation rate meet the criteria. If they do, exit the low-frequency load reduction control. If not, wait for the next round of low-frequency load reduction action. The criteria are as follows: After exiting the low-frequency load reduction control, gradually reduce the virtual inertia parameter H of the networking equipment. v , until it returns to its initial value H base ; Among them, f Hth is the low-frequency load shedding exit frequency threshold, ε Hth It is the frequency change rate threshold for exiting under-frequency load shedding.

8. A low-frequency load reduction control system with inertia support capability of network-type equipment, characterized in that: include: A calculation unit, used to collect operation status data of the power system, and calculate the support capacity index of the network-forming device based on the operation status data; A first execution unit, configured to dynamically calculate a multiple-round threshold of low-frequency load shedding based on the support capability index to determine whether to execute low-frequency load shedding control; The second execution unit is used for dynamically adjusting the virtual inertia parameters and judging whether to exit the low-frequency load reduction control based on the real-time frequency and the frequency deviation rate.

9. The low-frequency load reduction control system according to claim 8, characterized in that: The operating status data includes: The capacity of all grid-forming equipment and synchronous generators in the power grid.

10. The low-frequency load reduction control system according to claim 8, characterized in that: The calculation formula for calculating the support capability index of the networking device is as follows: Among them, η sup port is the support capacity index, is the equivalent virtual inertia time constant of the networked device, is the equivalent inertia time constant of the synchronous generator, S GFM is the sum of the capacities of all networking devices, S GEN is the sum of the capacities of all synchronous generators, m and n are the numbers of synchronous generators and grid-connecting equipment respectively.

11. The low-frequency load reduction control system according to claim 8, characterized in that: The dynamically calculating the multiple rounds of low-frequency load shedding thresholds based on the support capacity index includes: Initialize the basic frequency threshold of the low-frequency load shedding round k is the number of low-frequency load shedding rounds. It decreases gradually with each round; According to the supporting capacity of the converter, the low-frequency load shedding trigger threshold is dynamically adjusted. The threshold for each round is: Among them, γ (k) is the k-th round proportional coefficient.

12. The low-frequency load reduction control system according to claim 8, characterized in that: The determining whether to perform low-frequency load reduction control includes: When the system frequency And it continues to exceed the action delay T delay When , the kth round of low-frequency load reduction is triggered and load shedding control is adopted.

13. The low-frequency load reduction control system according to claim 8, characterized in that: The dynamic adjustment of the virtual inertia parameters includes: After each round of low-frequency load shedding is triggered, the virtual inertia parameter H is adjusted dynamically in real time according to the current load shedding amount and system frequency deviation. v , the calculation formula is as follows: Among them, H base is the initial virtual inertia time constant of the grid-forming equipment, f0 is the rated frequency of the grid, f(t) is the real-time frequency of the grid, P shed-i is the load shedding amount in the i-th round, P shed is the total load shedding amount; α is the frequency deviation weight coefficient; β is the load shedding weight coefficient.

14. The low-frequency load reduction control system according to claim 8, characterized in that: The determining whether to exit the low-frequency load reduction control includes: In the frequency recovery phase, determine whether the real-time frequency and frequency deviation rate meet the criteria. If they do, exit the low-frequency load reduction control. If not, wait for the next round of low-frequency load reduction action. The criteria are as follows: After exiting the low-frequency load reduction control, gradually reduce the virtual inertia parameter H of the networking equipment. v , until it returns to its initial value H base ; Among them, f Hth is the low-frequency load shedding exit frequency threshold, ε Hth It is the frequency change rate threshold for exiting under-frequency load shedding.

15. A computer device, characterized in that: include: one or more processors; a processor for executing one or more programs; When the one or more programs are executed by the one or more processors, the method according to any one of claims 1 to 7 is implemented.

16. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the method according to any one of claims 1 to 7 is implemented.

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