Method for evaluating short-circuit ratio level of new energy station
By dividing the regional power grid into zones and calculating the short-circuit ratio of new energy power plants, the problem of insufficient assessment speed and accuracy in existing technologies has been solved, and rapid and accurate short-circuit ratio assessment and power grid strength quantification have been achieved.
Patent Information
- Application Number
- CN202511031985.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-25
- Publication Date
- 2025-11-11
AI Technical Summary
Existing short-circuit ratio calculation models for renewable energy power plants cannot accurately balance assessment speed and accuracy, resulting in an inability to effectively assess the short-circuit ratio at the generator terminals and grid connection points of renewable energy plants at various voltage levels in the regional power grid.
By establishing a power system component parameter model for the regional power grid, the regional power grid is divided into zones, and the active power output of each thermal power unit, nuclear power plant, and hydropower plant is calculated. Combined with the output of wind power plants and photovoltaic power plants, the short-circuit ratio of new energy power plants is calculated using the Gauss-Seidel power flow model. An iterative method is used to optimize the simultaneity rate of wind power and photovoltaic power within the zone to match the transmission power of tie lines.
It enables rapid and accurate assessment of the short-circuit ratio of regional power grid renewable energy power stations, quantifies grid strength, guides power station operation, and ensures that the active power output of wind and photovoltaic power stations is maximized based on the cross-sectional limit.
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Figure CN120933966A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of new energy power generation technology in power systems, specifically to a method for evaluating the short-circuit ratio level of new energy power plants. Background Technology
[0002] As the proportion of new energy sources in the power system continues to increase, some regions lack the support of conventional hydropower, thermal power and other synchronous generating units, resulting in weak grid strength and prominent problems such as wideband oscillation and transient voltage instability. The formation of these problems is highly related to the large-scale integration of new energy sources into the power system, and these problems will become increasingly prominent as the proportion of new energy installed capacity continues to increase.
[0003] To address the series of issues brought about by the rapid development of new energy sources and ensure the safe and stable operation of the power system, the short-circuit ratio of new energy multi-station power plants is widely used by grid companies and provincial companies as an indicator to assess the recovery capability of power parameters such as voltage and frequency when a power system experiences a fault. However, due to the strong volatility and randomness of new energy output, and the constantly changing start-up and output levels of traditional units such as thermal power units throughout the year, the short-circuit ratio at the same busbar of the power system also varies at different times. Therefore, existing calculation models for the short-circuit ratio of new energy multi-station power plants cannot adequately balance assessment accuracy and calculation speed, resulting in an inability to accurately assess the short-circuit ratio at the generator terminals and grid connection points of new energy sources within a regional power grid at various voltage levels. Summary of the Invention
[0004] To address the issue of how to quickly and accurately assess the short-circuit ratio of new energy sources in a regional power grid, this application provides a method for assessing the short-circuit ratio of new energy power plants.
[0005] This application provides a method for evaluating the short-circuit ratio level of a new energy power station, including:
[0006] S1. Establish a power system component parameter model for the regional power grid;
[0007] S2. Divide the wind power plants and photovoltaic power stations in the regional power grid into zones;
[0008] S3. Based on the power system component parameter model, calculate the active power output of each thermal power unit, each nuclear power plant, and each hydropower plant in the regional power grid.
[0009] S4. New energy power station types include wind power plants and photovoltaic power plants. Based on the power system component parameter model and the partitioning in S2, the output of wind power plants and photovoltaic power plants in each partition is determined, thereby obtaining the output of wind power plants and photovoltaic power plants in the regional power grid. Then, combined with the active power output of each thermal power unit, each nuclear power plant, and each hydropower plant calculated in S3, the power system operating parameters in the regional power grid are determined. Based on the power system operating parameters in the regional power grid, the short-circuit ratio of each new energy power station at the generator terminal and grid connection point in each partition is calculated.
[0010] Preferably, S2 includes:
[0011] S21. Divide the regional power grid into dispatching areas, resulting in n dispatching areas, denoted as D1, D2, ..., D... N N represents the number of scheduling regions;
[0012] S22. Based on the wind resources within the regional power grid, the regional power grid is divided into several wind belts: A1, A2, ..., A W W represents the number of wind belts;
[0013] S23. Based on the optical resources within the regional power grid, the regional power grid is divided into several optical bands: C1, C2, ..., C P P represents the number of light bands;
[0014] S24. Divide the wind farms within the regional power grid into zones. The zone matrix for the wind farms is as follows:
[0015]
[0016] Among them, K nw Indicates scheduling region D n With wind belt A w The intersecting regions, n = 1, 2, ..., N, w = 1, 2, ..., W;
[0017] The zoning matrix of the photovoltaic power station is as follows:
[0018]
[0019] Among them, L pn Indicates scheduling region D n With light band C p The intersecting regions, p = 1, 2, ..., P;
[0020] Remove the empty set elements from the partition matrix of wind farms; the remaining elements are the wind farm partitions.
[0021] Remove the empty set elements from the partition matrix of the photovoltaic power station, and the remaining elements are the photovoltaic power station partitions.
[0022] Preferably, S3 includes:
[0023] Collect real-time operation data of the regional power grid for the previous year and obtain data at b time points within the regional power grid.
[0024] Based on the power system component parameter model of the regional power grid, the short-circuit ratio (SCR) prediction value at various time points within the regional power grid is calculated, and the SCR is used to determine the criteria. es :
[0025]
[0026] In the formula, SCR es μ is used as a criterion for judging the predicted short-circuit ratio of the regional power grid. thp μ thS μ l μ wind μ ph μ nup μ hyp These are the following factors: total active power output of thermal power units, total operating capacity of thermal power units, total load active power output, active power output of wind turbines, active power output of photovoltaic power plants, total active power output of nuclear power plants, and total active power output of hydropower plants.
[0027] R represents the number of thermal power plants within the regional power grid, and N... r N represents the number of operating thermal power units in the r-th thermal power plant within the regional power grid. nu For the number of power plants in the regional power grid, N hy The number of hydropower plants within the regional power grid;
[0028] p r,i For the total active power output of the i-th thermal power unit of the r-th thermal power plant within the regional power grid, S r,i The total start-up of the i-th thermal power unit in the r-th thermal power plant within the regional power grid; p nu,r For the active power output of the rth nuclear power plant in the regional power grid, p hy,r It contributes power to the rth hydropower plant within the regional power grid.
[0029] N load N represents the number of point loads within the regional power grid. wind N represents the number of wind farms within the regional power grid. ph The number of photovoltaic power plants;
[0030] p load,j Let p be the active power of the load at point j. wind,n For contributing to the nth wind farm, p ph,m It contributes power to the m-th photovoltaic power station;
[0031] SCR at all points within the regional power grid es Sort the data in descending order and select the b*r% SCR in the sorted data.es The corresponding active power output of each thermal power unit, each nuclear power plant, and each hydropower plant, r% is an empirical value.
[0032] Preferably, S4 includes:
[0033] Arbitrarily sort the wind farm and photovoltaic power station zones, and execute steps S41 to S44 for each zone in sequence until the short-circuit ratio of the new energy power station terminal and grid connection point of all zones has been calculated.
[0034] S41. Determine the initial values of the wind power simultaneity rate and photovoltaic simultaneity rate of the required calculation zone and other zones based on historical data, and calculate the active power output of wind power plants and photovoltaic power plants in each zone based on the corresponding installed capacity of each zone, thereby obtaining the active power output of each wind power plant and each photovoltaic power plant in the regional power grid.
[0035] S42. Based on the active power output of each wind farm, each photovoltaic power station, each thermal power unit calculated in S3, each nuclear power plant, and each hydropower plant within the regional power grid, calculate lines 1, 2, ..., 3 using the traditional Gauss-Seidel power flow model. n line1, line2, ... line n This represents the power of the regional power grid and the external tie lines, where n represents the number of tie lines between the regional power grid and the external power grid.
[0036] like Then switch to S43, line total The upper limit of transmission power between the regional power grid and external tie lines, ξ is a set threshold, ξ>0; if Then obtain the operating parameters of the power system within the regional power grid and switch to S44;
[0037] S43, if The wind power simulcast rate and photovoltaic simulcast rate of the currently required calculation zone remain unchanged, while the wind power simulcast rate and photovoltaic simulcast rate of other zones are reduced proportionally. Then the active power output of wind farms and photovoltaic power plants in each zone are recalculated, and the process is transferred to S42.
[0038] like The wind power simulcast rate and photovoltaic simulcast rate of the currently required partition remain unchanged, while the wind power simulcast rate and photovoltaic simulcast rate of other partitions are increased proportionally. Then the active power output of the wind farm and the active power output of the photovoltaic power station in each partition are recalculated, and the process is transferred to S42.
[0039] S44. Calculate the short-circuit ratio of the corresponding type of new energy power plant terminal and grid connection point in the required calculation zone based on the power system operation parameters in the regional power grid.
[0040] As a preferred option, the operating parameters of the power system within the regional power grid include
[0041] Z gewind,ii Z cowind,ii Z geph,ii Z coph,ii I gewind,i I cowind,i I geph,i I coph,i ,
[0042] in, These are the nominal voltage of the busbar node at the turbine end of the i-th wind farm and the nominal voltage of the busbar node at the grid connection point of the i-th wind farm, respectively.
[0043] These are the nominal voltage of the busbar node at the generator end of the i-th photovoltaic power station and the nominal voltage of the busbar node at the grid connection point of the i-th photovoltaic power station, respectively.
[0044] Z gewind,ii Z cowind,ii These are the equivalent self-impedance of the AC power grid at the generator bus of the i-th wind farm and the equivalent self-impedance of the AC power grid at the grid connection point bus of the i-th wind farm, respectively.
[0045] Z geph,ii Z coph,ii These are the equivalent self-impedance of the AC power grid at the generator bus of the i-th photovoltaic power station and the equivalent self-impedance of the AC power grid at the grid connection point bus of the i-th photovoltaic power station, respectively.
[0046] I gewind,i I cowind,i I geph,i I coph,i These are the short-circuit currents that can be provided at the turbine end of the i-th wind farm, the short-circuit currents that can be provided at the grid connection point of the i-th wind farm, the short-circuit currents that can be provided at the turbine end of the i-th photovoltaic power station, and the short-circuit currents that can be provided at the grid connection point of the i-th photovoltaic power station, respectively.
[0047] Let be the transfer impedance between the busbar at the grid connection point of the j-th wind farm and the grid connection point of the i-th wind farm; Let be the transfer impedance between the busbar at the grid connection point of the j-th photovoltaic power station and the grid connection point of the i-th photovoltaic power station; Let be the transfer impedance between the busbar at the grid connection point of the j-th photovoltaic power station and the turbine terminal of the i-th wind power plant; Let be the transfer impedance between the busbar at the grid connection point of the j-th wind farm and the generator terminal of the i-th photovoltaic power station;
[0048] Let be the transfer impedance between the busbar at the grid connection point of the j-th wind farm and the turbine terminal of the i-th wind farm. Let be the transfer impedance between the busbar at the grid connection point of the j-th photovoltaic power station and the generator terminal of the i-th photovoltaic power station; Let be the transfer impedance between the busbar at the grid connection point of the j-th photovoltaic power station and the turbine terminal of the i-th wind power plant; Let be the transfer impedance between the busbar at the grid connection point of the j-th wind farm and the generator terminal of the i-th photovoltaic power station.
[0049] As a preferred option, the short-circuit ratio at the turbine terminal of the i-th wind farm within the wind farm zone is:
[0050]
[0051] The short-circuit ratio of the grid connection point of the i-th wind farm within the wind farm zone is:
[0052]
[0053] The short-circuit ratio of the i-th photovoltaic power station within the photovoltaic power station zone is:
[0054]
[0055] The short-circuit ratio of the grid connection point of the i-th photovoltaic power station within the photovoltaic power station zone is:
[0056]
[0057] Where, N wind N represents the number of wind farms within the regional power grid. ph This refers to the number of photovoltaic power plants.
[0058] Preferably, S41 includes:
[0059] If the required calculation zone is a wind power zone, calculate the maximum wind power simultaneity rate of the wind power zone in the same month of last year, and record the time point a corresponding to the maximum wind power simultaneity rate. Also calculate the photovoltaic simultaneity rate of the required zone, the wind power simultaneity rate of other zones, and the photovoltaic simultaneity rate of the sum of the photovoltaic simultaneity rate and the wind power simultaneity rate corresponding to time point a.
[0060] If the required calculation zone is a photovoltaic power station zone, calculate the maximum photovoltaic simulcast rate of the photovoltaic power station zone in the same month of last year, and record the time point b corresponding to the maximum photovoltaic simulcast rate. The wind power simulcast rate of the required calculation zone, the wind power simulcast rate of other zones, and the photovoltaic simulcast rate are the photovoltaic simulcast rate and wind power simulcast rate corresponding to time point b.
[0061] The beneficial effects of this application are that the active power output characteristics of wind farms or photovoltaic power stations vary in different regions within the regional power grid, resulting in different short-circuit ratio levels. By setting zoning, the short-circuit ratio levels of wind farms or photovoltaic power stations in different regions within the regional power grid can be calculated specifically. Through iteration, this invention can make the total power transmitted between the regional power grid and external interconnections approach the upper limit of the power transmitted between the regional power grid and external interconnections. This ensures that the active power output of wind farms or photovoltaic power stations within the regional power grid remains at its maximum while guaranteeing the cross-sectional limit, and consequently, that the active power output of wind farms or photovoltaic power stations within the regional power grid remains at its minimum while guaranteeing the cross-sectional limit, thus providing a better assessment of the short-circuit ratio level of the regional power grid. The short-circuit ratio level of new energy power stations assessed in this application is the lowest operating short-circuit ratio of new energy power stations after removing extreme data. The assessed short-circuit ratio of new energy power stations can be used for quantitative analysis of the regional power grid strength and can provide guidance for the operation of various types of power stations, such as new energy power stations, thermal power plants, and nuclear power plants. Attached Figure Description
[0062] Figure 1 This is a flowchart illustrating the process of this application. Detailed Implementation
[0063] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0064] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.
[0065] The present application will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the application.
[0066] The evaluation method for the short-circuit ratio level of new energy power stations in this embodiment includes:
[0067] Step 1: Establish the power system component parameter model of the regional power grid:
[0068] Specifically, the parameter models of power system components mainly include transmission line parameter models, substation parameter models, traditional power plant parameter models, and new energy power plant models;
[0069] The transmission line parameter model in this embodiment includes line length and line type.
[0070] The substation parameter model includes the substation main transformer model, the substation voltage regulator model, and the substation load model.
[0071] The substation main transformer model includes the transformer's rated capacity, short-circuit loss, no-load loss, short-circuit voltage percentage, no-load current percentage, tap ratio, and tap location.
[0072] The substation voltage regulator model includes the input capacity, rated current, rated voltage, and capacitors / reactors.
[0073] The substation load model includes the load active power value, the load reactive power value, and the load type.
[0074] The conventional power plant parameter model in this implementation includes thermal power plant parameter models, nuclear power plant parameter models, and hydropower plant parameter models. Each of these models includes rated capacity, rated power, active power output, reactive power output, generator parameters, voltage regulator parameters, speed governor parameters, and P-step parameters.
[0075] This implementation of the new energy power station model includes a transmission line parameter model, a main transformer parameter model, a box-type substation model, and a wind turbine / photovoltaic generator model.
[0076] The parameter model for the transmission line includes the line length and the line type;
[0077] The main transformer parameter model and the box-type substation model both include the transformer's rated capacity, short-circuit loss, no-load loss, short-circuit voltage percentage, no-load current percentage, tap ratio and location;
[0078] The wind turbine / photovoltaic generator models include rated capacity, rated power, active power output, reactive power output, converter model, site-level controller model, and low-voltage / high-voltage control model.
[0079] Step 2: Divide the wind farms and photovoltaic power stations in the regional power grid into zones, including:
[0080] Step 21: Divide the regional power grid into dispatch areas, resulting in n dispatch areas, denoted as D1, D2, ..., D... N N represents the number of scheduling regions:
[0081] In some implementations, the dispatching zone levels are defined according to computational requirements. If the regional power grid is a grid dispatching management area (regional power grid dispatching and control center), then the dispatching zones can be divided into provincial dispatching management areas or local dispatching management areas. If the regional power grid is a provincial dispatching management area (municipal power grid dispatching and control center), then the dispatching zones can be divided into local dispatching management areas or county dispatching management areas. If the regional power grid is a local dispatching management area (county-level power grid dispatching and control center), then the dispatching zones can be divided into county dispatching management areas or 220kV substation management areas.
[0082] Step 22: Based on the wind resources within the regional power grid, divide the regional power grid into several wind belts: A1, A2, ..., A W W represents the number of wind belts;
[0083] Step 23: Based on the optical resources within the regional power grid, divide the regional power grid into several optical bands: C1, C2, ..., C P P represents the number of light bands;
[0084] Step 24: Divide the wind farms within the regional power grid into zones. The zone matrix for the wind farms is as follows:
[0085]
[0086] Among them, K nw Indicates scheduling region D n With wind belt A w The intersecting regions, n = 1, 2, ..., N, w = 1, 2, ..., W;
[0087] The zoning matrix of the photovoltaic power station is as follows:
[0088]
[0089] Among them, L pn Indicates scheduling region D n With light band C p The intersecting regions, p = 1, 2, ..., P;
[0090] Remove the empty set elements from the partition matrix of wind farms; the remaining elements are the wind farm partitions.
[0091] Remove the empty set elements from the partition matrix of the photovoltaic power station, and the remaining elements are the photovoltaic power station partitions.
[0092] Step 3: Based on the power system component parameter model, calculate the active power output of each thermal power unit, each nuclear power plant, and each hydropower plant in the regional power grid, including:
[0093] Step 31: Statistically analyze the real-time operation data of the regional power grid in the previous year, obtain data at b time points within the regional power grid, with one data point per hour, and obtain the total operating capacity and total active power output of thermal power units, total active power output of wind power, total active power output of photovoltaic power, and total load level of 8760 data points in the regional power grid;
[0094] Step 32: Based on the power system component parameter model of the regional power grid, calculate the predicted short-circuit ratio (SCR) at various time points within the regional power grid to determine the SCR criteria. es :
[0095] The short-circuit ratio of the regional power grid is strongly correlated with the total active power output of thermal power units, the total operating capacity of thermal power units, the active power of total load, the active power output of wind turbines, the active power output of photovoltaic power plants, the total active power output of nuclear power plants, and the total active power output of hydropower plants.
[0096]
[0097] In the formula, SCR es μ is used as a criterion for judging the predicted short-circuit ratio of the regional power grid. thp μ thS μ l μ wind μ ph μ nup μ hyp These are the following factors: total active power output of thermal power units, total operating capacity of thermal power units, total load active power output, active power output of wind turbines, active power output of photovoltaic power plants, total active power output of nuclear power plants, and total active power output of hydropower plants.
[0098] R represents the number of thermal power plants within the regional power grid, and N... r N represents the number of operating thermal power units in the r-th thermal power plant within the regional power grid. nu For the number of power plants in the regional power grid, N hy The number of hydropower plants within the regional power grid;
[0099] p r,i For the total active power output of the i-th thermal power unit of the r-th thermal power plant within the regional power grid, S r,i The total start-up of the i-th thermal power unit in the r-th thermal power plant within the regional power grid; p nu,r For the active power output of the rth nuclear power plant in the regional power grid, p hy,r It contributes power to the rth hydropower plant within the regional power grid.
[0100] N load N represents the number of point loads within the regional power grid. wind N represents the number of wind farms within the regional power grid. ph The number of photovoltaic power plants;
[0101] p load,j Let p be the active power of the load at point j. wind,n For contributing to the nth wind farm, p ph,m It contributes power to the m-th photovoltaic power station;
[0102] Step 33: Perform SCR testing on all points within the regional power grid. es Sort the data from largest to smallest, and select the b*r% (8760*r%) SCR in the sorted data. esThe corresponding active power output of each thermal power unit, each nuclear power plant, and each hydropower plant, r% is an empirical value, generally taken as 99% or 101%.
[0103] Step 4: New energy power station types include wind farms and photovoltaic power stations. Based on the power system component parameter model and the zoning in Step 2, determine the output of wind farms and photovoltaic power stations within each zone, thereby obtaining the output of wind farms and photovoltaic power stations in the regional power grid. Then, combine this with the active power output of each thermal power unit, each nuclear power plant, and each hydropower plant calculated in Step 3 to determine the power system operating parameters within the regional power grid. Based on the power system operating parameters within the regional power grid, calculate the short-circuit ratio at the generator terminals and grid connection points of each new energy power station in each zone, including:
[0104] Arbitrarily sort the wind farm zones and photovoltaic power station zones, and execute steps 41 to 44 in order for each zone until the short-circuit ratio of the new energy power station terminal and grid connection point of all zones has been calculated.
[0105] Step 41: Determine the initial values of the wind power simultaneity rate and photovoltaic simultaneity rate for the required calculation zone and other zones based on historical data. Then, based on the corresponding installed capacity of each zone, calculate the active power output of wind farms and photovoltaic power plants within each zone, thereby obtaining the active power output of each wind farm and each photovoltaic power plant within the regional power grid. Specifically,
[0106] If the required calculation zone is a wind power zone, calculate the maximum wind power simultaneity rate of the wind power zone in the same month of last year, and record the time point a corresponding to the maximum wind power simultaneity rate. Also calculate the photovoltaic simultaneity rate of the required zone, the wind power simultaneity rate of other zones, and the photovoltaic simultaneity rate of the sum of the photovoltaic simultaneity rate and the wind power simultaneity rate corresponding to time point a.
[0107] If the required calculation zone is a photovoltaic power station zone, calculate the maximum photovoltaic simulcast rate of the photovoltaic power station zone in the same month of last year, and record the time point b corresponding to the maximum photovoltaic simulcast rate. The wind power simulcast rate of the required calculation zone, the wind power simulcast rate of other zones, and the photovoltaic simulcast rate are the photovoltaic simulcast rate and wind power simulcast rate corresponding to time point b.
[0108] The active power output p of the nth wind farm within the zone wind,n =λ wind ·S wind,n The active power output p of the m-th photovoltaic power station within the zone ph,m =λ ph ·S ph,m , λ wind Let λ be the wind power simultaneity rate. ph S represents the photovoltaic simulacrum. wind,n Let S be the installed capacity of the nth wind farm within the zone. ph,m Let m be the installed capacity of the m-th photovoltaic power station within the zone;
[0109] Step 42: Based on the active power output of each wind farm, each photovoltaic power station, each thermal power unit calculated in Step 3, each nuclear power plant, and each hydropower plant within the regional power grid, calculate line1, line2, ... line using the traditional Gauss-Seidel power flow model. n line1, line2, ... line n This represents the power of the regional power grid and the external tie lines, where n represents the number of tie lines between the regional power grid and the external power grid.
[0110] like Then proceed to step 43, line total The upper limit of transmission power between the regional power grid and external tie lines, ξ is a set threshold, ξ>0; if Then obtain the operating parameters of the power system within the regional power grid and proceed to step 44;
[0111] Specifically, the operating parameters of the power system within the regional power grid include
[0112] Z gewind,ii Z cowind,ii Z geph,ii Z coph,ii I gewind,i I cowind,i I geph,i I coph,i ,
[0113] in, These are the nominal voltage of the busbar node at the turbine end of the i-th wind farm and the nominal voltage of the busbar node at the grid connection point of the i-th wind farm, respectively.
[0114] These are the nominal voltage of the busbar node at the generator end of the i-th photovoltaic power station and the nominal voltage of the busbar node at the grid connection point of the i-th photovoltaic power station, respectively.
[0115] Z gewind,ii Z cowind,ii These are the equivalent self-impedance of the AC power grid at the generator bus of the i-th wind farm and the equivalent self-impedance of the AC power grid at the grid connection point bus of the i-th wind farm, respectively.
[0116] Z geph,ii Z coph,ii These are the equivalent self-impedance of the AC power grid at the generator bus of the i-th photovoltaic power station and the equivalent self-impedance of the AC power grid at the grid connection point bus of the i-th photovoltaic power station, respectively.
[0117] I gewind,i I cowind,i I geph,i Icoph,i These are the short-circuit currents that can be provided at the turbine end of the i-th wind farm, the short-circuit currents that can be provided at the grid connection point of the i-th wind farm, the short-circuit currents that can be provided at the turbine end of the i-th photovoltaic power station, and the short-circuit currents that can be provided at the grid connection point of the i-th photovoltaic power station, respectively.
[0118] Let be the transfer impedance between the busbar at the grid connection point of the j-th wind farm and the grid connection point of the i-th wind farm; Let be the transfer impedance between the busbar at the grid connection point of the j-th photovoltaic power station and the grid connection point of the i-th photovoltaic power station; Let be the transfer impedance between the busbar at the grid connection point of the j-th photovoltaic power station and the turbine terminal of the i-th wind power plant; Let be the transfer impedance between the busbar at the grid connection point of the j-th wind farm and the generator terminal of the i-th photovoltaic power station;
[0119] Let be the transfer impedance between the busbar at the grid connection point of the j-th wind farm and the turbine terminal of the i-th wind farm. Let be the transfer impedance between the busbar at the grid connection point of the j-th photovoltaic power station and the generator terminal of the i-th photovoltaic power station; Let be the transfer impedance between the busbar at the grid connection point of the j-th photovoltaic power station and the turbine terminal of the i-th wind power plant; Let be the transfer impedance between the busbar at the grid connection point of the j-th wind farm and the generator terminal of the i-th photovoltaic power station.
[0120] Step 43, if The wind power simulcast rate and photovoltaic simulcast rate of the current required calculation zone remain unchanged, while the wind power simulcast rate and photovoltaic simulcast rate of other zones are reduced proportionally by a reduction factor of 99%. That is, the current wind power simulcast rate and photovoltaic simulcast rate are multiplied by 99% to obtain the updated wind power simulcast rate and photovoltaic simulcast rate. Then, the active power output of the wind farm and the active power output of the photovoltaic power station in each zone are recalculated, and the process proceeds to step 42.
[0121] like The wind power simulcast rate and photovoltaic simulcast rate of the current required zone remain unchanged, while the wind power simulcast rate and photovoltaic simulcast rate of other zones are increased proportionally by an increase factor of 101%. That is, the current wind power simulcast rate and photovoltaic simulcast rate are multiplied by 101% to obtain the updated wind power simulcast rate and photovoltaic simulcast rate. Then, the active power output of the wind farm and the active power output of the photovoltaic power station in each zone are recalculated, and the process proceeds to step 42.
[0122] Step 44: Calculate the short-circuit ratios at the turbine terminals and grid connection points of the corresponding types of new energy power plants within the required calculation zone based on the power system operating parameters within the regional power grid: The short-circuit ratio at the turbine terminal of the i-th wind farm within the wind farm zone is:
[0123]
[0124] The short-circuit ratio of the grid connection point of the i-th wind farm within the wind farm zone is:
[0125]
[0126] The short-circuit ratio of the i-th photovoltaic power station within the photovoltaic power station zone is:
[0127]
[0128] The short-circuit ratio of the grid connection point of the i-th photovoltaic power station within the photovoltaic power station zone is:
[0129]
[0130] Where, N wind N represents the number of wind farms within the regional power grid. ph This refers to the number of photovoltaic power plants.
[0131] While this application has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of this application. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of this application as defined by the appended claims. It should be understood that different dependent claims and features herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other embodiments.
Claims
1. A method for evaluating the short-circuit ratio level of new energy power plants, characterized in that, include: S1. Establish a power system component parameter model for the regional power grid; S2. Divide the wind power plants and photovoltaic power stations in the regional power grid into zones; S3. Based on the power system component parameter model, calculate the active power output of each thermal power unit, each nuclear power plant, and each hydropower plant in the regional power grid. S4. New energy power station types include wind power plants and photovoltaic power plants. Based on the power system component parameter model and the partitioning in S2, the output of wind power plants and photovoltaic power plants in each partition is determined, thereby obtaining the output of wind power plants and photovoltaic power plants in the regional power grid. Then, combined with the active power output of each thermal power unit, each nuclear power plant, and each hydropower plant calculated in S3, the power system operating parameters in the regional power grid are determined. Based on the power system operating parameters in the regional power grid, the short-circuit ratio of each new energy power station at the generator terminal and grid connection point in each partition is calculated.
2. The method for evaluating the short-circuit ratio level of new energy power stations according to claim 1, characterized in that, S2 includes: S21. Divide the regional power grid into dispatching areas, resulting in n dispatching areas, denoted as D1, D2, ..., D... N N represents the number of scheduling regions; S22. Based on the wind resources within the regional power grid, the regional power grid is divided into several wind belts: A1, A2, ..., A W W represents the number of wind belts; S23. Based on the optical resources within the regional power grid, the regional power grid is divided into several optical zones: C1, C2, ..., C P P represents the number of light bands; S24. Divide the wind farms within the regional power grid into zones. The zone matrix for the wind farms is as follows: Among them, K nw Indicates scheduling region D n With wind belt A w The intersecting regions, n = 1, 2, ..., N, w = 1, 2, ..., W; The zoning matrix of the photovoltaic power station is as follows: Among them, L pn Indicates scheduling region D n With light band C p The intersecting regions, p = 1, 2, ..., P; Remove the empty set elements from the partition matrix of wind farms; the remaining elements are the wind farm partitions. Remove the empty set elements from the partition matrix of the photovoltaic power station, and the remaining elements are the photovoltaic power station partitions.
3. The method for evaluating the short-circuit ratio level of new energy power stations according to claim 1, characterized in that, S3 includes: Collect real-time operation data of the regional power grid for the previous year and obtain data at b time points within the regional power grid. Based on the power system component parameter model of the regional power grid, the short-circuit ratio (SCR) prediction value at various time points within the regional power grid is calculated, and the SCR is used to determine the criteria. es : In the formula, SCR es μ is used as a criterion for judging the predicted short-circuit ratio of the regional power grid. thp μ thS μ l μ wind μ ph μ nup μ hyp These are the following factors: total active power output of thermal power units, total operating capacity of thermal power units, total load active power output, active power output of wind turbines, active power output of photovoltaic power plants, total active power output of nuclear power plants, and total active power output of hydropower plants. R represents the number of thermal power plants within the regional power grid, and N represents the number of thermal power plants within the regional power grid. r N represents the number of operating thermal power units in the r-th thermal power plant within the regional power grid. nu For the number of power plants in the regional power grid, N hy The number of hydropower plants within the regional power grid; p r,i For the total active power output of the i-th thermal power unit of the r-th thermal power plant within the regional power grid, S r,i The total start-up of the i-th thermal power unit in the r-th thermal power plant within the regional power grid; p nu,r For the active power output of the rth nuclear power plant in the regional power grid, p hy,r It contributes power to the rth hydropower plant within the regional power grid. N load N represents the number of point loads within the regional power grid. wind N represents the number of wind farms within the regional power grid. ph The number of photovoltaic power plants; p load,j Let p be the active power of the load at point j. wind,n For contributing to the nth wind farm, p ph,m It contributes power to the m-th photovoltaic power station; SCR at all points within the regional power grid es Sort the data in descending order and select the b*r% SCR in the sorted data. es The corresponding active power output of each thermal power unit, each nuclear power plant, and each hydropower plant, r% is an empirical value.
4. The method for evaluating the short-circuit ratio level of new energy power stations according to claim 1, characterized in that, S4 include: Arbitrarily sort the wind farm and photovoltaic power station zones, and execute steps S41 to S44 for each zone in sequence until the short-circuit ratio of the new energy power station terminal and grid connection point of all zones is calculated. S41. Determine the initial values of the wind power simultaneity rate and photovoltaic simultaneity rate of the required calculation zone and other zones based on historical data, and calculate the active power output of wind power plants and photovoltaic power plants in each zone based on the corresponding installed capacity of each zone, thereby obtaining the active power output of each wind power plant and each photovoltaic power plant in the regional power grid. S42. Based on the active power output of each wind farm, each photovoltaic power station, each thermal power unit calculated in S3, each nuclear power plant, and each hydropower plant within the regional power grid, calculate lines 1, 2, ..., 3 using the traditional Gauss-Seidel power flow model. n line1, line2, ... line n This represents the power of the regional power grid and the external tie lines, where n represents the number of tie lines between the regional power grid and the external power grid. like Then switch to S43, line total The upper limit of transmission power between the regional power grid and external tie lines, ξ is a set threshold, ξ>0; if Then obtain the operating parameters of the power system within the regional power grid and switch to S44; S43, if The wind power simulcast rate and photovoltaic simulcast rate of the currently required calculation zone remain unchanged, while the wind power simulcast rate and photovoltaic simulcast rate of other zones are reduced proportionally. Then the active power output of wind farms and photovoltaic power plants in each zone are recalculated, and the process is transferred to S42. like The wind power simulcast rate and photovoltaic simulcast rate of the currently required partition remain unchanged, while the wind power simulcast rate and photovoltaic simulcast rate of other partitions are increased proportionally. Then the active power output of the wind farm and the active power output of the photovoltaic power station in each partition are recalculated, and the process is transferred to S42. S44. Calculate the short-circuit ratio of the corresponding type of new energy power plant terminal and grid connection point in the required calculation zone based on the power system operation parameters in the regional power grid.
5. The method for evaluating the short-circuit ratio level of new energy power stations according to claim 4, characterized in that, Operating parameters of the power system within the regional power grid include Z gewind,ii Z cowind,ii Z geph,ii Z coph,ii I gewind,i I cowind,i I geph,i I coph,i , in, These are the nominal voltage of the busbar node at the turbine end of the i-th wind farm and the nominal voltage of the busbar node at the grid connection point of the i-th wind farm, respectively. These are the nominal voltage of the busbar node at the generator end of the i-th photovoltaic power station and the nominal voltage of the busbar node at the grid connection point of the i-th photovoltaic power station, respectively. Z gewind,ii Z cowind,ii These are the equivalent self-impedance of the AC power grid at the generator bus of the i-th wind farm and the equivalent self-impedance of the AC power grid at the grid connection point bus of the i-th wind farm, respectively. Z geph,ii Z coph,ii These are the equivalent self-impedance of the AC power grid at the generator bus of the i-th photovoltaic power station and the equivalent self-impedance of the AC power grid at the grid connection point bus of the i-th photovoltaic power station, respectively. I gewind,i I cowind,i I geph,i I coph,i These are the short-circuit currents that can be provided at the turbine end of the i-th wind farm, the short-circuit currents that can be provided at the grid connection point of the i-th wind farm, the short-circuit currents that can be provided at the turbine end of the i-th photovoltaic power station, and the short-circuit currents that can be provided at the grid connection point of the i-th photovoltaic power station, respectively. Let be the transfer impedance between the busbar at the grid connection point of the j-th wind farm and the grid connection point of the i-th wind farm; Let be the transfer impedance between the busbar at the grid connection point of the j-th photovoltaic power station and the grid connection point of the i-th photovoltaic power station; Let be the transfer impedance between the busbar at the grid connection point of the j-th photovoltaic power station and the turbine terminal of the i-th wind power plant; Let be the transfer impedance between the busbar at the grid connection point of the j-th wind farm and the generator terminal of the i-th photovoltaic power station; Let be the transfer impedance between the busbar at the grid connection point of the j-th wind farm and the turbine terminal of the i-th wind farm. Let be the transfer impedance between the busbar at the grid connection point of the j-th photovoltaic power station and the generator terminal of the i-th photovoltaic power station; Let be the transfer impedance between the busbar at the grid connection point of the j-th photovoltaic power station and the turbine terminal of the i-th wind power plant; Let be the transfer impedance between the busbar at the grid connection point of the j-th wind farm and the generator terminal of the i-th photovoltaic power station.
6. The method for evaluating the short-circuit ratio level of new energy power stations according to claim 5, characterized in that, The short-circuit ratio at the turbine terminal of the i-th wind farm within the wind farm zone is: The short-circuit ratio of the grid connection point of the i-th wind farm within the wind farm zone is: The short-circuit ratio of the i-th photovoltaic power station within the photovoltaic power station zone is: The short-circuit ratio of the grid connection point of the i-th photovoltaic power station within the photovoltaic power station zone is: Where, N wind N represents the number of wind farms within the regional power grid. ph This refers to the number of photovoltaic power plants.
7. The method for evaluating the short-circuit ratio level of new energy power stations according to claim 4, characterized in that, S41 includes: If the required calculation zone is a wind power zone, calculate the maximum wind power simultaneity rate of the wind power zone in the same month of last year, and record the time point a corresponding to the maximum wind power simultaneity rate. Also calculate the photovoltaic simultaneity rate of the required zone, the wind power simultaneity rate of other zones, and the photovoltaic simultaneity rate of the sum of the photovoltaic simultaneity rate and the wind power simultaneity rate corresponding to time point a. If the required calculation zone is a photovoltaic power station zone, calculate the maximum photovoltaic simulcast rate of the photovoltaic power station zone in the same month of last year, and record the time point b corresponding to the maximum photovoltaic simulcast rate. The wind power simulcast rate of the required calculation zone, the wind power simulcast rate of other zones, and the photovoltaic simulcast rate are the photovoltaic simulcast rate and wind power simulcast rate corresponding to time point b.
8. A computer-readable storage device storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for evaluating the short-circuit ratio level of new energy power stations as described in any one of claims 1 to 7.
9. An evaluation device for the short-circuit ratio level of a new energy power station, comprising a storage device, a processor, and a computer program stored in the storage device and executable on the processor, characterized in that, The processor executes the computer program to implement the steps of the method for evaluating the short-circuit ratio level of new energy power stations as described in any one of claims 1 to 7.
10. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the steps of the method for evaluating the short-circuit ratio level of new energy power stations as described in any one of claims 1 to 7.