Load reduction methods and systems considering the protection actions of new energy power stations

Abstract

This invention discloses a load reduction method that takes into account the protection actions of renewable energy power plants. The method includes: real-time acquisition of the system frequency by each substation; obtaining the disconnection time of the renewable energy unit based on the system frequency; calculating the renewable energy disconnection power loss of the substation based on the frequency drop rate obtained at the disconnection time; obtaining the average renewable energy disconnection power loss of the substation within the system based on the renewable energy disconnection power loss of the substation; if the average renewable energy disconnection power loss of the substation is less than the current minimum granularity of the load that can be cut off, then no disconnection is performed; otherwise, a priority search is conducted for cut-off line loads until the cut-off line load exceeds the average renewable energy disconnection power loss of the substation; and the searched cut-off line loads are then cut off. This invention enables timely and effective load reduction for renewable energy unit disconnections.

Description

Technical Field

[0001] This invention belongs to the field of power system safety and stability technology, and in particular relates to a load reduction method and system that takes into account the protection actions of new energy power plants. Background Technology

[0002] In recent years, my country's new energy development has been rapid, with wind power and photovoltaic grid-connected capacity ranking first in the world. Guided by the goal of "carbon peaking and carbon neutrality," the proportion of new energy in my country will further increase. The rapid development of new energy and its unique distributed nature have fundamentally changed the characteristics of the power grid. With the widespread integration of new energy-consuming devices such as distributed power sources, microgrids, energy storage, and electric vehicles, the power supply and demand patterns are becoming more diversified, and load characteristics are showing significant differences and complementarity. The proportion of traditional load lines with dual "source and load" characteristics is constantly increasing. For a certain distributed photovoltaic grid-connected line, because the output of photovoltaic power generation fluctuates due to the influence of solar irradiance, the line may exhibit power source characteristics at noon and load characteristics at night.

[0003] For a long time, low-frequency load shedding devices have served as a crucial third line of defense for power system safety and stability, playing a vital role in ensuring the safe and stable operation of the power system and preventing major power outages. In existing technologies, a regional load coordination control master station is established. Low-frequency load shedding substations installed in each substation collect electrical quantity information from each 35kV / 10kV line connected to the substation and transmit it to the master station. The master station performs comprehensive load coordination control within the region, determining the load lines to be shelved in each round at each substation and issuing this information to the substations. When making comprehensive decision-making, the master station excludes lines with negative power (with the outflow bus as the positive direction) and only includes lines with the attribute of "load" in the standby line selection. However, existing technologies suffer from problems such as excessively large load shedding granularity and a lack of comprehensive consideration of the protection of renewable energy power plants. Specifically:

[0004] (1) Although a 35kV / 10kV line has a positive overall power direction at a certain moment, it contains a large amount of photovoltaic power. If the entire line is disconnected, the load disconnected from the system side is relatively small, while the power component of the load is relatively large after removing the negative power component of the photovoltaic power source in the line. Such load disconnection has a small contribution to the frequency stability of the system side, but the actual impact on production and daily life is large. The actual size of the disconnected load is also difficult to quantify, and the harm of the negative impact on society is difficult to assess. For the system side, the control resources that can be mobilized are small, which may lead to the load control quantity not meeting the requirements.

[0005] (2) When the frequency is lower than a certain value, it may trigger the protection action of the new energy power station side, causing the photovoltaic / wind turbine units to be disconnected from the grid collectively, resulting in an increase in instantaneous power deficit. If load shedding measures are not taken in a targeted manner, the frequency may be further reduced, triggering a chain reaction and ultimately leading to grid collapse, which seriously threatens the stability of grid frequency and voltage. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a load reduction method and system that takes into account the protection actions of new energy power plants, which can effectively and promptly reduce the load when new energy units disconnect from the grid.

[0007] The technical problem to be solved by the present invention is achieved through the following technical solution:

[0008] Firstly, a load reduction method considering the protection actions on the new energy power station side is provided, including:

[0009] Each substation obtains the system frequency in real time;

[0010] The off-grid time of the new energy device is obtained based on the system frequency, and the off-grid power loss of the substation's new energy is calculated based on the frequency decline rate obtained at the off-grid time.

[0011] The average power loss of new energy sources disconnected from the grid in the substations is obtained based on the power loss of new energy sources disconnected from the grid in the substations.

[0012] If the average power loss of the new energy source disconnected from the substation is less than the minimum granularity of the current load that can be cut off, then no disconnection will be performed; otherwise, the load that can be cut off will be searched according to priority until the load that can be cut off is greater than the average power loss of the new energy source disconnected from the substation.

[0013] Cut off the loads of the cut-off lines identified in the search.

[0014] In conjunction with the first aspect, further, obtaining the grid disconnection time of the new energy device based on the system frequency includes:

[0015] Determine if the system frequency is lower than the low-frequency protection setting f l_set If it is lower than the low-frequency protection setting f, then the setting will be based on the low-frequency protection setting f. l_set The moment it started and the operation of new energy in f l_set The following is the continuous runtime T l_set The moment when the new energy device is disconnected from the grid is obtained.

[0016] In conjunction with the first aspect, further, the calculation of the substation's renewable energy disconnection power based on the frequency decline rate obtained at the disconnection time includes:

[0017] The system frequency is lower than the low-frequency protection setting f. l_set Let the initial time be denoted as t0, and the time T after t0 be denoted as t0. l-setTake three time points t1, t2, and t3 near time -Δt, and calculate the system frequency decrease rate at these three points {df / dt|t=t1, t2, t3}, where f is the system frequency; substitute the system frequency decrease rate at these three time points t1, t2, and t3 into equation (1).

[0018]

[0019] The difference between mechanical power and electrical power at this moment can be calculated and denoted as (P). m -P e ), steady damping coefficient D, and equivalent rotational inertia J of the system; where ω is the actual angular velocity, Δω is the difference in electrical angular velocity, and P m P e T after t0 l-set Mechanical power and electrical power at time -Δt, T m T e These are mechanical torque and electromagnetic torque, respectively.

[0020] T after t0 l-set Take three time points t1', t2', and t3' near the +Δt time, and calculate the system frequency decrease rate {df / dt|t=t1', t2', t3'} at these three time points. Substitute the system frequency decrease rates at these three time points t1', t2', and t3' into equation (1) to obtain the difference between mechanical power and electrical power at this time, denoted as (P m -P e )'; will (P m -P e ), (P m -P e Substituting into equation (2), we obtain the power loss P of the new energy source disconnected from the grid. loss

[0021] (P m -P e )'=P' m -P e '=P m -P e '=P m -(P e +P loss )=(P m -P e )-P loss (2)

[0022] Among them, P' m P e 'Represents T after t0 respectively l-set Mechanical power and electrical power at time +Δt.

[0023] In conjunction with the first aspect, further, the step of obtaining the average power loss of renewable energy disconnection from the substation within the system based on the power loss of renewable energy disconnection from the substation includes:

[0024] The power loss P of new energy off-grid at each substation within the system loss The average power loss P of new energy off-grid at the substation is obtained by summing the data from the main station and dividing by the number of substations. loss_ave .

[0025] In conjunction with the first aspect, further prioritization includes:

[0026] For a load line, several evaluation indicators are set, and a weight is assigned to each evaluation indicator. The score of each evaluation indicator on the load line is multiplied by its weight and then summed to obtain the weighted comprehensive score of the load line. The weighted comprehensive scores of each load line are sorted from high to low, and the higher the score, the earlier it is cut off.

[0027] In conjunction with the first aspect, the determination of switchable line load further includes:

[0028] Set up collection points in the line to collect electrical quantity information, and lower the direction of the collection points so that the collected lines only contain loads or power sources. Lines with negative power direction are excluded, and the rest are currently cut-off lines.

[0029] Secondly, a load reduction system that takes into account the protection actions of the new energy power station side is provided, including:

[0030] The system frequency acquisition module is used by each substation to acquire the system frequency in real time.

[0031] The power loss calculation module is used to obtain the grid disconnection time of the new energy device based on the system frequency, and to calculate the grid disconnection power of the new energy at the substation based on the frequency decline rate obtained at the grid disconnection time.

[0032] The average power loss of new energy sources disconnected from the grid in the substations is obtained based on the power loss of new energy sources disconnected from the grid in the substations.

[0033] The load shedding module is used to prevent shedding if the average power loss of the new energy source disconnected from the substation is less than the minimum granularity of the current load that can be shelded; otherwise, it searches for sheldable line loads according to priority until the sheldable line load is greater than the average power loss of the new energy source disconnected from the substation.

[0034] Cut off the loads of the cut-off lines identified in the search.

[0035] In conjunction with the second aspect, the operations performed by the power loss calculation module further include:

[0036] The system frequency is lower than the low-frequency protection setting f. l_set Let the initial time be denoted as t0, and the time T after t0 be denoted as t0. l-setTake three time points t1, t2, and t3 near time -Δt, and calculate the system frequency decrease rate at these three points {df / dt|t=t1, t2, t3}, where f is the system frequency; substitute the system frequency decrease rate at these three time points t1, t2, and t3 into equation (1).

[0037]

[0038] The difference between mechanical power and electrical power at this moment can be calculated and denoted as (P). m -P e ), steady damping coefficient D, and equivalent rotational inertia J of the system; where ω is the actual angular velocity, Δω is the difference in electrical angular velocity, and P m P e T after t0 l-set Mechanical power and electrical power at time -Δt;

[0039] T after t0 l-set Take three time points t1', t2', and t3' near the +Δt time, and calculate the system frequency decrease rate {df / dt|t=t1', t2', t3'} at these three time points. Substitute the system frequency decrease rates at these three time points t1', t2', and t3' into equation (1) to obtain the difference between mechanical power and electrical power at this time, denoted as (P m -P e )'; will (P m -P e ), (P m -P e Substituting into equation (2), we obtain the power loss P of the new energy source disconnected from the grid. loss

[0040] (P m -P e )'=P' m -P e '=P m -P e '=P m -(P e +P loss )=(P m -P e )-P loss (2)

[0041] Among them, P' m P e 'Represents T after t0 respectively l-set Mechanical power and electrical power at time +Δt.

[0042] In conjunction with the second aspect, the operations performed by the load shedding module further include:

[0043] For a load line, several evaluation indicators are set, and a weight is assigned to each evaluation indicator. The score of each evaluation indicator on the load line is multiplied by its weight and then summed to obtain the weighted comprehensive score of the load line. The weighted comprehensive scores of each load line are sorted from high to low, and the higher the score, the earlier it is cut off.

[0044] The beneficial effects of this invention include:

[0045] 1) Taking into account the protection operation of the new energy power station side, when the system frequency is lower than the low-frequency protection operation setting f of the new energy power station side. l_set And the continuous running time is greater than the maximum allowed running time T. l_set In anticipation of the impending system frequency drop caused by the collective disconnection of photovoltaic / wind turbine units due to the protection action on the new energy power plant side, additional load shedding is carried out in advance. This action is taken before the frequency drops further to stabilize the grid frequency and avoid a chain reaction that could lead to grid collapse, thereby maintaining the stability of the grid frequency and voltage.

[0046] 2) Refine the load shedding granularity by shifting the load electrical quantity acquisition points downwards to collect electrical quantity information at lower voltage levels or branch line switches. Separate lines with the attribute of "source" and the attribute of "load" as much as possible. This will allow for the minimum load shedding when the system-side control quantity is the same, thereby reducing the impact on the social economy and production and living conditions. At the same time, it can ensure that the system load control quantity meets the required shedding quantity to the greatest extent. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the line electrical quantity acquisition location for the load reduction method of the new energy power station side protection action in this invention;

[0048] Figure 2 This is a flowchart of the load removal process in this invention. Detailed Implementation

[0049] To further describe the technical features and effects of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0050] like Figure 1 As shown, the present invention provides a load reduction method that takes into account the protection actions of the new energy power station side, including the following steps:

[0051] Step 1: Each substation acquires the system frequency in real time.

[0052] Step 2: Obtain the power loss of renewable energy when the substation is disconnected from the grid.

[0053] Is the given system frequency lower than the low-frequency protection setting f? l_set If new energy sources (photovoltaics / wind turbines) operate at f l_set The following continues with Tl_set After a certain time, the grid will be disconnected. The frequency drop rate is calculated at Δt before and Δt after the disconnection time, and the power loss P of the new energy source due to grid disconnection is calculated accordingly. loss Specifically, it includes:

[0054] The system frequency is lower than the low-frequency protection setting f. l_set Let the initial time be denoted as t0, and the time T after t0 be denoted as t0. l-set -Take any three time points t1, t2, and t3 around time Δt, with an interval of less than 20ms. Δt is a very short time interval, selected based on experience to avoid possible timing errors. Calculate the system frequency drop rate at these three points {df / dt|t=t1, t2, t3}, where f is the system frequency.

[0055] The power grid is a rotating system, and its torque balance equation is as follows:

[0056]

[0057] Among them, T m and T e These are mechanical torque and electromagnetic torque, ω b ω and ω are the rated electric angular velocity and the actual electric angular velocity, respectively, and the difference in electric angular velocity Δω = ω - ω b Substituting ω=2πf into equation (1) yields the following equation:

[0058]

[0059] Substituting the system frequency decrease rates at time points t1, t2, and t3 into equation (2)

[0060] The difference between mechanical power and electrical power at this moment can be calculated and denoted as (P). m -P e ), steady damping coefficient D and system equivalent moment of inertia J; where P m P e T after t0 l-set Mechanical power and electrical power at time -Δt;

[0061] T after t0 l-set Take three time points t1', t2', and t3' near the +Δt time, and calculate the system frequency decrease rate {df / dt|t=t1', t2', t3'} at these three time points. Substitute the system frequency decrease rate at these three time points t1', t2', and t3' into equation (2) to obtain the difference between mechanical power and electrical power at this time, denoted as (P m -P e )'; will (P m -P e ), (Pm -P e Substituting into equation (3), we obtain the power loss P of the new energy source disconnected from the grid. loss

[0062] Mechanical power can be considered constant over a very short period of time, therefore P m =P' m Therefore there is

[0063] (P m -P e )'=P' m -P e '=P m -P e '=P m -(P e +P loss )=(P m -P e )-P loss (3)

[0064] Step 3: Calculate the average power loss P when the new energy source is disconnected from the grid. loss_ave

[0065] The power loss P of new energy off-grid at each substation within the system loss The average power loss P of new energy off-grid at the substation is obtained by summing the data from the main station and dividing by the number of substations. loss_ave .

[0066] Step 4: Load Removal

[0067] To ensure that only loads are cut off as much as possible, the focus of load electrical quantity data needs to be shifted downwards. For example, instead of the current practice of collecting single-phase voltage and current data from 35kV / 10kV lines, data from lower voltage levels or branch line switches should be collected, and so on down to large-scale renewable energy grid connection points or residential switch points (for distributed photovoltaic power generation in households). The specific location of the collection points should be determined based on the distribution of grid load and distributed power sources, taking into account cost, construction difficulty, and benefits. The principle is to ensure that the collected data on the lines contains only loads or only power sources. A data collection and execution unit is installed at the collection point. This unit interacts with the substation's low-frequency load shedding substation via the existing 2M channel, 5G wireless technology, or access to the distribution communication network. It transmits the collected single-phase voltage and current data of the load lines and receives load shedding commands from the substation.

[0068] The main station excludes lines with negative power direction (i.e., lines with the attribute "source"), and the remaining lines are the currently switchable lines. All switchable lines are sorted according to load priority and geographical attributes to form a two-dimensional list of switchable lines, as shown in Table 1.

[0069] The priority setting is specifically as follows:

[0070] For a load line, several evaluation indicators are set, and a weight is assigned to each evaluation indicator. The score of each evaluation indicator on the load line is multiplied by its weight and then summed to obtain the weighted comprehensive score of the load line. The weighted comprehensive scores of each load line are sorted from high to low, and the higher the score, the earlier it is cut off.

[0071] Table 1. Sequence of Cuttable Lines

[0072]

[0073] Among them, P ji This represents the load that can be switched on the i-th substation with the j-th priority.

[0074] The specific resection process is as follows:

[0075] If the average power loss P when the new energy source is disconnected from the grid loss_ave If the load size is smaller than the current minimum granularity that can be cut off, the device will not perform any additional actions; if the power loss P due to the disconnection of the renewable energy source is... loss_ave If the load exceeds the minimum granularity of the current available load, the main station searches for available load lines sequentially according to the order of priority and geographical attributes in the two-dimensional list 1. The search is performed row by row, and when a row is finished, the search proceeds to the next row until the total load of the searched available lines reaches the additional load P to be cut. loss_ave Stop the search when the load needs to be cut.

[0076] Example 2

[0077] The present invention also provides a load reduction system that takes into account the protection actions of the new energy power station side, comprising:

[0078] The system frequency acquisition module is used by each substation to acquire the system frequency in real time.

[0079] The power loss calculation module is used to obtain the grid disconnection time of the new energy device based on the system frequency, and to calculate the grid disconnection power of the new energy at the substation based on the frequency decline rate obtained at the grid disconnection time.

[0080] The average power loss of new energy sources disconnected from the grid in the substations is obtained based on the power loss of new energy sources disconnected from the grid in the substations.

[0081] The load shedding module is used to prevent shedding if the average power loss of the new energy source disconnected from the substation is less than the minimum granularity of the current load that can be shelded; otherwise, it searches for sheldable line loads according to priority until the sheldable line load is greater than the average power loss of the new energy source disconnected from the substation.

[0082] Cut off the loads of the cut-off lines identified in the search.

[0083] The operations performed by the power loss calculation module include:

[0084] The system frequency is lower than the low-frequency protection setting f. l_set Let the initial time be denoted as t0, and the time T after t0 be denoted as t0. l-set Take three time points t1, t2, and t3 near time Δt, and calculate the system frequency decrease rate at these three points {df / dt|t=t1, t2, t3}, where f is the system frequency; substitute the system frequency decrease rate at these three time points t1, t2, and t3 into equation (4).

[0085]

[0086] The difference between mechanical power and electrical power at this moment can be calculated and denoted as (P). m -P e ), steady damping coefficient D, and equivalent rotational inertia J of the system; where ω is the actual angular velocity, Δω is the difference in electrical angular velocity, and P m P e T after t0 l-set Mechanical power and electrical power at time -Δt;

[0087] T after t0 l-set Take three time points t1', t2', and t3' near the +Δt time, and calculate the system frequency decrease rate {df / dt|t=t1', t2', t3'} at these three time points. Substitute the system frequency decrease rates at these three time points t1', t2', and t3' into equation (1) to obtain the difference between mechanical power and electrical power at this time, denoted as (P m -P e )'; will (P m -P e ), (P m -P e Substituting into equation (5), we obtain the power loss P of the new energy source disconnected from the grid. loss

[0088] (P m -P e )'=P' m -P e '=P m -P e '=P m -(P e +P loss )=(P m -P e )-P loss (5)

[0089] Among them, P' m P e 'Represents T after t0 respectivelyl-set Mechanical power and electrical power at time +Δt.

[0090] The operations performed by the load shedding module include:

[0091] For a load line, several evaluation indicators are set, and a weight is assigned to each evaluation indicator. The score of each evaluation indicator on the load line is multiplied by its weight and then summed to obtain the weighted comprehensive score of the load line. The weighted comprehensive scores of each load line are sorted from high to low, and the higher the score, the earlier it is cut off.

[0092] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0093] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0094] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0095] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1The steps of the function specified in one or more boxes.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A load reduction method taking into account the protection actions of new energy power station sides, characterized in that, include: Each substation obtains the system frequency in real time; The off-grid time of new energy devices is obtained based on the system frequency, including: Determine if the system frequency is lower than the low-frequency protection setting. If it is lower, then it should be based on the low-frequency protection setting. The moment it started and the operation of new energy sources The following continuous runtime Obtain the time when the new energy device is disconnected from the grid; The power loss due to grid disconnection of the substation's renewable energy is calculated based on the frequency decay rate obtained at the time of grid disconnection, including: The system frequency is lower than the low-frequency protection setting. The initial time is denoted as , After Take three time points near the current time. , and Find the rate of decrease of the system frequency at these three points. ,in For system frequency; , and Substituting the system frequency decrease rate at these three time points into equation (1): （1）； The difference between mechanical power and electrical power at this moment can be calculated and denoted as . steady damping coefficient and the system's equivalent rotational inertia ;in, This is the actual angular velocity. For the difference in electric angular velocity, , They are respectively After Mechanical power and electrical power at any given moment For mechanical torque, Electromagnetic torque; exist After Take three time points near the current time. , and The rate of decrease of the system frequency at these three time points was obtained. ,Will , and Substituting the system frequency decay rate at these three time points into equation (1) yields the difference between mechanical power and electrical power at that moment, denoted as . ;Will , Substituting into equation (2), the power loss due to grid disconnection of new energy sources is obtained. ; （2）； in, , They represent After Mechanical and electrical power at any given moment; The average power loss of new energy sources disconnected from the grid in the substations is obtained based on the power loss of new energy sources disconnected from the grid in the substations. If the average power loss of the new energy source disconnected from the substation is less than the minimum granularity of the current load that can be cut off, then no disconnection will be performed; otherwise, the load that can be cut off will be searched according to priority until the load that can be cut off is greater than the average power loss of the new energy source disconnected from the substation. Cut off the loads of the cut-off lines identified in the search.

2. The load reduction method considering the protection actions of new energy power station side according to claim 1, characterized in that, The method of obtaining the average power loss of renewable energy disconnection from substations within the system based on the power loss of renewable energy disconnection from substations includes: The power loss of new energy sources when disconnected from the grid at each substation within the system. The average power loss of renewable energy off-grid at a substation is obtained by summing the data from the main station and dividing by the number of substations. .

3. The load reduction method considering the protection actions of new energy power station side according to claim 1, characterized in that, Priority settings include: For a load line, several evaluation indicators are set, and a weight is assigned to each evaluation indicator. The score of each evaluation indicator on the load line is multiplied by its weight and then summed to obtain the weighted comprehensive score of the load line. The weighted comprehensive scores of each load line are sorted from high to low, and the higher the score, the earlier it is cut off.

4. The load reduction method considering the protection action of the new energy power station side according to claim 1, characterized in that, The determination of cut-off line load includes: Set up collection points in the line to collect electrical quantity information, and lower the direction of the collection points so that the collected lines only contain loads or power sources. Lines with negative power direction are excluded, and the rest are currently cut-off lines.

5. A load reduction system taking into account the protection actions of the new energy power station side, used to implement the load reduction method taking into account the protection actions of the new energy power station side as described in claim 1, characterized in that, include: The system frequency acquisition module is used by each substation to acquire the system frequency in real time. The power loss calculation module is used to obtain the grid disconnection time of the new energy device based on the system frequency, and to calculate the grid disconnection power of the new energy at the substation based on the frequency decline rate obtained at the grid disconnection time. The average power loss of new energy sources disconnected from the grid in the substations is obtained based on the power loss of new energy sources disconnected from the grid in the substations. The load shedding module is used to prevent shedding if the average power loss of the new energy source disconnected from the substation is less than the minimum granularity of the current load that can be shelded; otherwise, it searches for sheldable line loads according to priority until the sheldable line load is greater than the average power loss of the new energy source disconnected from the substation. Cut off the loads of the disconnectable lines identified in the search.

6. A load reduction system considering the protection actions of new energy power station side according to claim 5, characterized in that, The operations performed by the power loss calculation module include: The system frequency is lower than the low-frequency protection setting. The initial time is denoted as , After Take three time points near the current time. , and Find the rate of decrease of the system frequency at these three points. ,in For system frequency; , and Substituting the system frequency decrease rate at these three time points into equation (1) （1） The difference between mechanical power and electrical power at this moment can be calculated and denoted as . steady damping coefficient and the system's equivalent rotational inertia ;in, This is the actual angular velocity. For the difference in electric angular velocity, , They are respectively After Mechanical power and electrical power at any given moment , These are mechanical torque and electromagnetic torque, respectively. exist After Take three time points near the current time. , and The rate of decrease of the system frequency at these three time points was obtained. ,Will , and Substituting the system frequency decay rate at these three time points into equation (1) yields the difference between mechanical power and electrical power at that moment, denoted as . ;Will , Substituting into equation (2), the power loss due to grid disconnection of new energy sources is obtained. ; （2） in, , They represent After Mechanical power and electrical power at any given moment.

7. A load reduction system considering the protection actions of new energy power station side according to claim 5, characterized in that, The operations performed by the load shedding module include: For a load line, several evaluation indicators are set, and a weight is assigned to each evaluation indicator. The score of each evaluation indicator on the load line is multiplied by its weight and then summed to obtain the weighted comprehensive score of the load line. The weighted comprehensive scores of each load line are sorted from high to low, and the higher the score, the earlier it is cut off.

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