A method, device, and storage medium for determining a measurement window of the power grid frequency change rate

Abstract

The present invention relates to the technical field of power system frequency change rate measurement, and discloses a method, device and storage medium for determining a power grid frequency change rate measurement window. The present invention determines the total system kinetic energy and typical N-2 faults under the target operation mode, determines the unbalanced power of the system after each typical N-2 fault occurs, and further calculates the theoretical value of the system frequency change rate corresponding to the corresponding target fault; determines the target frequency change rate measurement point; constructs a target constraint condition for the measurement parameter values of different target frequency change rate measurement points corresponding to each target fault under different frequency change rate measurement window values, uses minimizing the frequency change rate measurement window as the objective function, and establishes a frequency change rate measurement window optimization model; optimizes and solves the model to obtain the optimal frequency change rate measurement window and outputs it. The present invention can solve the optimal value of the power grid frequency change rate measurement window under high-proportion new energy penetration, and has the advantages of wide applicability and high flexibility.

Description

Technical Field

[0001] The present invention relates to the technical field of power system frequency change rate measurement, and particularly to a method, device and storage medium for determining a measurement window of power grid frequency change rate. Background Art

[0002] The system frequency change rate is a measurable index closely related to the inertia of the power system. The accurate measurement of this index helps to determine the system inertia and anti-disturbance ability under the penetration of a high proportion of new energy, and may provide a basis for judging the stable operation control of the regional power grid in the future. The measurement methods of the frequency change rate mainly involve three aspects: filters, measurement algorithms, and measurement windows. Among them, the selection of the measurement window has a great impact on the measurement of the frequency change rate and is a key factor for accurately measuring the frequency change rate.

[0003] Currently, a measurement window with a fixed value is used for measuring the frequency change rate, and this fixed value is generally 500 ms. For a traditional power system mainly composed of synchronous machines, its system inertia is large and the anti-disturbance ability is strong. Therefore, under normal large disturbances, the system frequency change rate is small. The method of using a measurement window with a fixed value to measure the frequency change rate can measure the frequency change rate more accurately.

[0004] However, with the rapid development of a new type of power system under the scenario of high proportion of new energy penetration, synchronous machines are gradually withdrawn from the power system, the system inertia of the power grid decreases, and the anti-disturbance ability becomes weaker. Under large disturbance scenarios, the system frequency changes rapidly and the frequency change rate becomes higher. The existing scheme of using a measurement window with a fixed value to measure the frequency change rate is difficult to be applicable to the rapidly developing new type of power system. Among them, an overly long measurement window will lead to delays in the measurement of the frequency change rate and a decrease in the absolute value of the measurement data. At the same time, it is difficult to reflect the dynamic response characteristics of the actual local power grid system, and may cause the relevant measurements, configurations and responses of some new energy inverters to be difficult to match the power system, thus triggering new problems. And an overly short measurement window for the frequency change rate will cause large deviations in the measured frequency change rate at each sampling point of the power grid, and may also cause large errors in the measured frequency change rate due to waveform distortion and other influences. Summary of the Invention

[0005] The present invention provides a method, device and storage medium for determining a measurement window of power grid frequency change rate, which can be applicable to the calculation of the measurement window of the frequency change rate under different regional power systems and different operation modes, and plays an important role in the inertia estimation, risk assessment and stable operation control decision-making of a new type of power system under high proportion of new energy penetration in the future, and solves the technical problem that the existing scheme of using a measurement window with a fixed value to measure the frequency change rate is difficult to be applicable to the power system under high proportion of new energy penetration.

[0006] The first aspect of the present invention provides a method for determining a power grid frequency change rate measurement window, including:

[0007] Determine the total system kinetic energy of the target power grid under the target operating mode; the target operating mode is the operating mode corresponding to the minimum system moment of inertia of the target power grid;

[0008] Determine the typical N-2 faults of the target power grid under the target operating mode to obtain a target fault set;

[0009] Determine the unbalanced power of the system after each target fault occurs; the target fault is a fault in the target fault set;

[0010] Calculate the system frequency change rate corresponding to the corresponding target fault according to the unbalanced power and the total system kinetic energy, and obtain the theoretical values of the system frequency change rates corresponding to each target fault;

[0011] Determine each frequency change rate measurement point distributed in the key areas of the target power grid to obtain a target frequency change rate measurement point set;

[0012] Construct target constraint conditions for the measurement parameter values of different target frequency change rate measurement points corresponding to each target fault under different frequency change rate measurement window values; the target frequency change rate measurement point is a frequency change rate measurement point in the target frequency change rate measurement point set; the measurement parameter values include the maximum value of the frequency change rate measurement value and the frequency change rate measurement deviation during the period when the target fault occurs; the target frequency change rate measurement point is a frequency change rate measurement point in the target frequency change rate measurement point set; the target constraint conditions include: the frequency change rate measurement window value is between the preset window initial value and the preset window maximum allowable value, the maximum value of all frequency change rate measurement deviations is not greater than the frequency change rate measurement deviation fixed value, and the maximum value of each frequency change rate measurement value is not greater than the corresponding system frequency change rate theoretical value;

[0013] Take minimizing the frequency change rate measurement window as the objective function, and establish a frequency change rate measurement window optimization model according to the objective function and the target constraint conditions;

[0014] Optimize and solve the frequency change rate measurement window optimization model to obtain and output the optimal frequency change rate measurement window.

[0015] According to an implementable manner of the first aspect of the present invention, the determining the total system kinetic energy of the target power grid under the target operating mode includes:

[0016] Taking the minimization of the number of synchronized generator units in operation, the maximization of the total output of new energy generator units, and the minimization of the inertia constant of synchronized generator units as the constraint conditions of the operating mode, determine the target operating mode of the target power grid;

[0017] Calculate the total system kinetic energy of the target power grid under the target operation mode.

[0018] According to an implementable manner of the first aspect of the present invention, the calculating the total system kinetic energy of the target power grid under the target operation mode includes:

[0019] Calculate the total system kinetic energy of the target power grid under the target operation mode according to the following formula:

[0020] E sys = E SG + E IM + E V(VS) + E V(CS) + E Load

[0021] In the formula, E sys represents the total system kinetic energy of the target power grid under the target operation mode, E SG represents the total kinetic energy of the synchronous generator sets, E IM represents the total kinetic energy of the asynchronous induction motors, E V(VS) represents the energy form of the voltage source type virtual inertia, E V(CS) represents the energy form of the current source type virtual inertia, E Load represents the energy form of the static load voltage equivalent inertia.

[0022] According to an implementable manner of the first aspect of the present invention, the calculating the system frequency change rate corresponding to the corresponding target fault according to the unbalanced power and the total system kinetic energy, and obtaining the theoretical value of the system frequency change rate corresponding to each target fault includes:

[0023] Calculate the system frequency change rate corresponding to each target fault according to the following formula:

[0024]

[0025] In the formula, RoCoF theory (i) is the system frequency change rate corresponding to the target fault i, f0 is the system rated frequency, ΔP i is the unbalanced power of the system after the occurrence of the target fault i, and E sys is the total system kinetic energy of the target power grid under the target operation mode.

[0026] According to an implementable manner of the first aspect of the present invention, in the target constraint condition, the occurrence time of the target fault is used as the lower bound of the target fault occurrence period, and the sum of the occurrence time of the target fault and the preset fault time factor is used as the upper bound of the target fault occurrence period.

[0027] According to an implementable manner of the first aspect of the present invention, establishing the rate of change of frequency measurement window optimization model according to the objective function and the objective constraint conditions includes:

[0028] The rate of change of frequency measurement window optimization model is established as:

[0029]

[0030] s.t.

[0031] T0 ≤ T ≤ T max

[0032] max{[max(RoCoF i,j,T (t)) - min(RoCoF i,j,T (t)), t ∈ [t0, t0 + τ]], i ∈ Ω F , j ∈ Ω M} ≤ ∈

[0033] max{RoCoF i,j,T (t), t ∈ [t0, t0 + τ]} ≤ RoCoF theory (i)

[0034] In the formula, T represents the rate of change of frequency measurement window value, T0 represents the initial value of the preset window, T max represents the maximum allowable value of the preset window, Ω F represents the target fault set, Ω M represents the target rate of change of frequency measurement point set, RoCoF i,j,T (t) represents the rate of change of frequency measurement value at time t during the occurrence period of the target fault for the rate of change of frequency measurement point j corresponding to the target fault i when the rate of change of frequency measurement window value is T, t0 is the target fault occurrence time, τ is the preset fault time factor, RoCoF theory (i) is the system rate of change of frequency corresponding to the target fault i, and ∈ is the rate of change of frequency measurement deviation fixed value.

[0035] According to an implementable manner of the first aspect of the present invention, optimizing and solving the rate of change of frequency measurement window optimization model includes:

[0036] By gradually increasing the rate of change of frequency measurement window value, solve the rate of change of frequency measurement window optimization model.

[0037] The second aspect of the present invention provides a device for determining the rate of change of frequency measurement window of a power grid, including:

[0038] The first determination module is used to determine the total system kinetic energy of the target power grid under the target operation mode; the target operation mode is the operation mode corresponding to the minimum system moment of inertia of the target power grid;

[0039] The second determination module is used to determine the typical N-2 faults of the target power grid under the target operation mode, and obtain a target fault set;

[0040] The third determination module is used to determine the unbalanced power of the system after each target fault occurs; the target fault is the fault in the target fault set;

[0041] The calculation module is used to calculate the system frequency change rate corresponding to the corresponding target fault according to the unbalanced power and the total system kinetic energy, and obtain the theoretical value of the system frequency change rate corresponding to each target fault;

[0042] The fourth determination module is used to determine the frequency change rate measurement points distributed in the key areas of the target power grid, and obtain a target frequency change rate measurement point set;

[0043] The first construction module is used to construct target constraint conditions for the measurement parameter values of different target frequency change rate measurement points corresponding to each target fault under different frequency change rate measurement window values; the target frequency change rate measurement point is the frequency change rate measurement point in the target frequency change rate measurement point set; the measurement parameter value includes the maximum value of the frequency change rate measurement value and the frequency change rate measurement deviation during the period when the target fault occurs; the target frequency change rate measurement point is the frequency change rate measurement point in the target frequency change rate measurement point set; the target constraint conditions include: the frequency change rate measurement window value is between the preset window initial value and the preset window maximum allowable value, the maximum value of all frequency change rate measurement deviations is not greater than the frequency change rate measurement deviation fixed value, and the maximum value of each frequency change rate measurement value is not greater than the corresponding system frequency change rate theoretical value;

[0044] The second construction module is used to establish a frequency change rate measurement window optimization model with minimizing the frequency change rate measurement window as the objective function according to the objective function and the target constraint conditions;

[0045] The solution module is used to optimize and solve the frequency change rate measurement window optimization model, and obtain and output the optimal frequency change rate measurement window.

[0046] According to an implementable manner of the second aspect of the present invention, the first determination module includes:

[0047] The determination unit is used to determine the target operation mode of the target power grid with minimizing the number of synchronous units in operation, maximizing the total output of new energy units, and minimizing the inertia constant of synchronous units as the constraint conditions of the operation mode;

[0048] A first calculation unit for calculating the total system kinetic energy of the target power grid under the target operation mode.

[0049] According to an implementable manner of the second aspect of the present invention, the first calculation unit is specifically configured to:

[0050] Calculate the total system kinetic energy of the target power grid under the target operation mode according to the following formula:

[0051] E sys = E SG + E IM + E V(VS) + E V(CS) + E Load

[0052] In the formula, E sys represents the total system kinetic energy of the target power grid under the target operation mode, E SG represents the total kinetic energy of synchronous generators, E IM represents the total kinetic energy of asynchronous induction motors, E V(VS) represents the energy form of voltage source type virtual inertia, E V(CS) represents the energy form of current source type virtual inertia, E Load represents the energy form of the equivalent inertia of static load voltage.

[0053] According to an implementable manner of the second aspect of the present invention, the calculation module includes:

[0054] A second calculation unit for calculating the system frequency change rate corresponding to each target fault according to the following formula:

[0055]

[0056] In the formula, RoCoF theory (i) is the system frequency change rate corresponding to the target fault i, f0 is the system rated frequency, ΔP i is the unbalanced power of the system after the occurrence of the target fault i, and E sys is the total system kinetic energy of the target power grid under the target operation mode.

[0057] According to an implementable manner of the second aspect of the present invention, in the target constraint condition, the occurrence time of the target fault is used as the lower bound of the target fault occurrence period, and the sum of the occurrence time of the target fault and the preset fault time factor is used as the upper bound of the target fault occurrence period.

[0058] According to an implementable manner of the second aspect of the present invention, the second construction module includes:

[0059] A model - building unit, configured to build an optimized model for the rate - of - change - of - frequency measurement window as follows:

[0060]

[0061]

[0062] T0≤T≤T max

[0063] max{[max(RoCoF i,j,T (t)) - min(RoCoF i,j,T (t)),t∈[t0,t0 + τ]],i∈Ω F ,j∈Ω M}≤∈

[0064] max{RoCoF i,j,T (t),t∈[t0,t0 + τ]}≤RoCoF theory (i)

[0065] In the formula, T represents the value of the rate - of - change - of - frequency measurement window, T0 represents the initial value of the preset window, T max represents the maximum allowable value of the preset window, Ω F represents the set of target faults, Ω M represents the set of target rate - of - change - of - frequency measurement points, RoCoF i,j,T (t) represents the rate - of - change - of - frequency measurement value at time t within the occurrence period of the target fault for the measurement point j corresponding to the target fault i when the value of the rate - of - change - of - frequency measurement window is T, t0 is the occurrence time of the target fault, τ is the preset fault time factor, RoCoF theory (i) is the system rate of change of frequency corresponding to the target fault i, and ∈ is the rate - of - change - of - frequency measurement deviation fixed value.

[0066] According to an implementable manner of the second aspect of the present invention, the solving module includes:

[0067] A solving unit, configured to solve the optimized model of the rate - of - change - of - frequency measurement window by gradually increasing the value of the rate - of - change - of - frequency measurement window.

[0068] The third aspect of the present invention provides a device for determining a rate - of - change - of - frequency measurement window of a power grid, including:

[0069] A memory, configured to store instructions; wherein, the instructions are used to implement the method for determining a rate - of - change - of - frequency measurement window of a power grid as described in any one of the above - mentioned implementable manners;

[0070] A processor, configured to execute the instructions in the memory.

[0071] In a fourth aspect of the present invention, a computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the method for determining a grid frequency change rate measurement window described in any of the above realizable manners.

[0072] As can be seen from the above technical solutions, the present invention has the following advantages:

[0073] The present invention takes the operating mode corresponding to the minimum system inertia of the target power grid as the target operating mode, determines the total system kinetic energy and typical N-2 faults under the target operating mode, determines the unbalanced power of the system after each typical N-2 fault occurs, and then calculates the system frequency change rate corresponding to the corresponding target fault to obtain the theoretical values of the system frequency change rates corresponding to each target fault; determines each frequency change rate measurement point distributed in the key areas of the target power grid as the target frequency change rate measurement point; constructs target constraint conditions for the measurement parameter values of different target frequency change rate measurement points corresponding to each target fault under different frequency change rate measurement window values, takes the minimum frequency change rate measurement window as the objective function, and establishes an optimization model for the frequency change rate measurement window; optimizes and solves the optimization model of the frequency change rate measurement window to obtain and output the optimal frequency change rate measurement window; the present invention can solve the optimal value of the grid frequency change rate measurement window under high-proportion new energy penetration, can flexibly adjust the corresponding parameters according to actual needs to ensure that the solved frequency change rate measurement window value is applicable to the system. When parameters such as relevant stability control and power electronics control of the system change, only by changing the constraint setting value can the updated frequency change rate measurement window value be calculated, so that it can be applicable to the calculation of the frequency change rate measurement window under different regional power systems and different operating modes, and plays an important role in the inertia estimation, risk assessment, and stability control decision-making of the future new power system under high-proportion new energy penetration. Description of the Drawings

[0074] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0075] Figure 1 It is a flowchart of a method for determining a grid frequency change rate measurement window provided for an optional embodiment of the present invention;

[0076] Figure 2 It is a structural connection block diagram of a device for determining a grid frequency change rate measurement window provided for an optional embodiment of the present invention.

[0077] Reference signs:

[0078] 1 - First determination module; 2 - Second determination module; 3 - Third determination module; 4 - Calculation module; 5 - Fourth determination module; 6 - First construction module; 7 - Second construction module; 8 - Solution module. Detailed implementation manners

[0079] An embodiment of the present invention provides a method, device and storage medium for determining a measurement window of grid frequency change rate, which are used to solve the technical problem that the existing scheme of measuring the frequency change rate by using a measurement window with a fixed value is difficult to be applicable to a power system under high - proportion new - energy penetration.

[0080] In order to make the invention purpose, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0081] The present invention provides a method for determining a measurement window of grid frequency change rate.

[0082] Please refer to Figure 1 , Figure 1 , which shows a flowchart of a method for determining a measurement window of grid frequency change rate provided by an embodiment of the present invention.

[0083] A method for determining a measurement window of grid frequency change rate provided by an embodiment of the present invention includes steps S1 - S8.

[0084] Step S1, determining the total system kinetic energy of the target power grid under the target operation mode; the target operation mode is the operation mode corresponding to the minimum system moment of inertia of the target power grid.

[0085] When determining the total system kinetic energy of the target power grid under the target operation mode, it is necessary to determine the target operation mode. In the embodiments of the present application, the operation mode corresponding to the minimum system moment of inertia of the target power grid is used as the target operation mode.

[0086] Among them, the determination of the typical extreme operation mode of the target power grid needs to comprehensively consider three constraint conditions:

[0087] (1) The number of synchronous units started is as small as possible;

[0088] (2) The total output of new - energy units is as high as possible;

[0089] (3) Try to start the synchronous generator units with a small moment of inertia (small inertia constant).

[0090] By comprehensively considering the above three conditions, a typical extreme operating mode of the power grid can be established. Under this mode, the system inertia is small, and the system frequency is the most sensitive to disturbances. Therefore, the boundary (i.e., the maximum value) of the frequency change rate measurement window can be determined based on this operating mode.

[0091] Thus, as a specific implementation, taking the minimization of the number of started synchronous generator units, the maximization of the total output of new energy generator units, and the minimization of the inertia constant of synchronous generator units as the constraint conditions of the operating mode, determine the target operating mode of the target power grid.

[0092] In a realizable manner, calculate the total system kinetic energy of the target power grid in the target operating mode according to the following formula:

[0093] E sys =E SG +E IM +E V(VS) +E V(CS) +E Load

[0094] In the formula, E sys represents the total system kinetic energy of the target power grid in the target operating mode, E SG represents the total kinetic energy of synchronous generator units, E IM represents the total kinetic energy of asynchronous induction motors, E V(VS) represents the energy form of voltage-source type virtual inertia, E V(CS) represents the energy form of current-source type virtual inertia, E Load represents the energy form of the equivalent inertia of static load voltage.

[0095] Step S2: Determine the typical N-2 faults of the target power grid in the target operating mode to obtain a target fault set.

[0096] If there are P typical N-2 faults in the target power grid in the target operating mode, then this target fault set can be expressed as:

[0097] Ω F ={i|i=1,2,…,P}

[0098] In the formula, Ω F represents the target fault set.

[0099] It should be noted that the types of typical N-2 faults can be selected from the existing N-2 fault types according to the actual situation. In this embodiment, no limitation is made in this regard.

[0100] Step S3: Determine the unbalanced power of the system after each target fault occurs; the target fault is a fault in the target fault set.

[0101] Step S4: Calculate the system frequency change rate corresponding to the corresponding target fault according to the unbalanced power and the total kinetic energy of the system, and obtain the theoretical value of the system frequency change rate corresponding to each target fault.

[0102] In an implementable manner, the calculating the system frequency change rate corresponding to the corresponding target fault according to the unbalanced power and the total kinetic energy of the system, and obtaining the theoretical value of the system frequency change rate corresponding to each target fault includes:

[0103] Calculate the system frequency change rate corresponding to each target fault according to the following formula:

[0104]

[0105] In the formula, RoCoF theory (i) is the system frequency change rate corresponding to target fault i, f0 is the rated frequency of the system, ΔP i is the unbalanced power of the system after target fault i occurs, E sys is the total kinetic energy of the target power grid under the target operation mode.

[0106] In this embodiment, calculating the system frequency change rate corresponding to each target fault according to the above formula is simple and convenient.

[0107] Step S5: Determine each frequency change rate measurement point distributed in the key areas of the target power grid to obtain a set of target frequency change rate measurement points.

[0108] Among them, the key area of the target power grid can be set according to the actual situation. If there are Q frequency change rate measurement points arranged in the key area of the target power grid, the set of target frequency change rate measurement points can be expressed as:

[0109] Ω M ={j|j=1,2,…,Q}

[0110] In the formula, Ω M represents the set of target frequency change rate measurement points.

[0111] Step S6: Construct target constraint conditions for the measurement parameter values of different target frequency change rate measurement points corresponding to each target fault under different frequency change rate measurement window values.

[0112] Among them, the target rate-of-change-of-frequency measurement point is the rate-of-change-of-frequency measurement point in the set of target rate-of-change-of-frequency measurement points; the measurement parameter value includes the maximum value of the rate-of-change-of-frequency measurement value and the rate-of-change-of-frequency measurement deviation within the target fault occurrence period; the target rate-of-change-of-frequency measurement point is the rate-of-change-of-frequency measurement point in the set of target rate-of-change-of-frequency measurement points; the target constraint conditions include: the rate-of-change-of-frequency measurement window value is between the preset window initial value and the maximum allowable value of the preset window, the maximum value among all the rate-of-change-of-frequency measurement deviations is not greater than the fixed value of the rate-of-change-of-frequency measurement deviation, and the maximum value of each rate-of-change-of-frequency measurement value is not greater than the corresponding theoretical value of the system rate-of-change-of-frequency.

[0113] In this embodiment, three constraint conditions are set as the target preset conditions. Among them, the first constraint condition is that the rate-of-change-of-frequency measurement window value is between the preset window initial value and the maximum allowable value of the preset window, the second constraint condition is that the maximum value among all the rate-of-change-of-frequency measurement deviations is not greater than the fixed value of the rate-of-change-of-frequency measurement deviation, and the third constraint condition is that the maximum value of each rate-of-change-of-frequency measurement value is not greater than the corresponding theoretical value of the system rate-of-change-of-frequency.

[0114] As a specific implementation manner, the rate-of-change-of-frequency measurement deviation within the target fault occurrence period is the difference between the maximum value and the minimum value of the rate-of-change-of-frequency measurement values within the target fault occurrence period. Based on this implementation manner, the corresponding second constraint condition is as follows:

[0115] max{[max(RoCoF i,j,T (t))-min(RoCoF i,j,T (t)),t∈[t0,t0+τ]],i∈Ω F ,j∈Ω M}≤∈

[0116] In the formula, Ω F represents the set of target faults, Ω M represents the set of target rate-of-change-of-frequency measurement points, RoCoF i,j,T (t) represents the rate-of-change-of-frequency measurement value at time t within the occurrence period of the target fault for the rate-of-change-of-frequency measurement point j corresponding to the target fault i when the rate-of-change-of-frequency measurement window value is T, t0 is the target fault occurrence time, τ is the preset fault time factor, and ∈ is the fixed value of the rate-of-change-of-frequency measurement deviation.

[0117] In other embodiments, the maximum value of the rate-of-change-of-frequency measurement values and the average value of the second-largest value of the rate-of-change-of-frequency measurement values within the target fault occurrence period can be calculated as the first calculated value, and the minimum value of the rate-of-change-of-frequency measurement values and the average value of the second-smallest value of the rate-of-change-of-frequency measurement values within the target fault occurrence period can be calculated as the second calculated value. Furthermore, the difference between the first calculated value and the second calculated value is calculated as the rate-of-change-of-frequency measurement deviation within the target fault occurrence period. Based on this embodiment, the corresponding second constraint condition is as follows:

[0118] max{[max'(RoCoF i,j,T (t))-min'(RoCoF i,j,T (t)),t∈[t0,t0+τ]],i∈Ω F ,j∈Ω M}≤∈

[0119] where:

[0120]

[0121]

[0122] In the formula, max -1 (RoCoF i,j,T (t)) is the second-largest value of the rate-of-change-of-frequency measurement values, and min -1 (RoCoF i,j,T (t)) is the second-smallest value of the rate-of-change-of-frequency measurement values within the target fault occurrence period.

[0123] In an implementable manner, in the target constraint condition, the target fault occurrence time is used as the lower bound of the target fault occurrence period, and the sum of the target fault occurrence time and the preset fault time factor is used as the upper bound of the target fault occurrence period.

[0124] Step S7: Using the minimum rate-of-change-of-frequency measurement window as the objective function, establish an optimization model for the rate-of-change-of-frequency measurement window according to the objective function and the target constraint condition.

[0125] In an implementable manner, the established optimization model for the rate-of-change-of-frequency measurement window is:

[0126]

[0127] s.t.

[0128] T0≤T≤T max

[0129] max{[max(RoCoF i,j,T (t))-min(RoCoF i,j,T(t)), where t ∈ [t0, t0 + τ]], i ∈ Ω F , j ∈ Ω M} ≤ ∈

[0130] max{RoCoF i,j,T (t), where t ∈ [t0, t0 + τ]} ≤ RoCoF theory (i)

[0131] In the formula, T represents the frequency change rate measurement window value, T0 represents the initial value of the preset window, T max represents the maximum allowable value of the preset window, Ω F represents the target fault set, Ω M represents the set of target frequency change rate measurement points, RoCoF i,j,T (t) represents the frequency change rate measurement value at time t during the occurrence period of the target fault for the measurement point j corresponding to the target fault i when the frequency change rate measurement window value is T. t0 is the occurrence time of the target fault, τ is the preset fault time factor, RoCoF theory (i) is the system frequency change rate corresponding to the target fault i, and ∈ is the fixed value of the frequency change rate measurement deviation.

[0132] Among them, the fixed value ∈ of the frequency change rate measurement deviation is determined by the measurement accuracy required for power grid stability control; the preset fault time factor τ can be determined by the fault response characteristics of the power grid; the initial value T0 of the preset window can be determined by the original measurement window value of the system; the maximum allowable value T of the preset window max can be determined by the setting values of various power grid stability control systems and the response time of power electronic devices, etc., to ensure that the measurement delay caused by this measurement window will not affect the action of the system stability control strategy and the action of power electronic devices participating in system control.

[0133] Step S8: Optimize and solve the frequency change rate measurement window optimization model to obtain the optimal frequency change rate measurement window and output it.

[0134] In an implementable manner, the optimizing and solving the frequency change rate measurement window optimization model includes:

[0135] Solving the frequency change rate measurement window optimization model by gradually increasing the frequency change rate measurement window value.

[0136] In this embodiment, the computational significance of solving the optimized model of the frequency change rate measurement window is that, through simulation, the frequency change rate measurement deviations at each moment within a certain period after a fault are calculated for all typical N-2 faults and all frequency change rate measurement points under the fault set. By gradually increasing the frequency change rate measurement window value, when a suitable frequency change rate measurement window value is selected such that all frequency change rate measurement deviations are less than a given fixed value of the frequency change rate measurement deviation, it can be determined that this frequency change rate measurement window value is the required value.

[0137] Considering the computational amount, when solving the frequency change rate measurement window, the time increased each time can be flexibly adjusted. As an implementable method, when gradually increasing the frequency change rate measurement window value, it is set that the frequency change rate measurement window value increases by at least 10 ms each time.

[0138] The above embodiments of the present invention can achieve unexpected technical effects:

[0139] It is possible to flexibly adjust the corresponding parameters according to actual needs to ensure that the solved frequency change rate measurement window value is applicable to the system; when parameters such as relevant stability control and power electronics control of the system change, only by changing the constraint fixed value can the updated frequency change rate measurement window value be calculated, with high flexibility, and it can be applicable to the calculation of the frequency change rate measurement window under different regional power systems and different operation modes, playing an important role in the inertia estimation, risk assessment, and stability control decision-making of the new power system with high proportion of new energy penetration in the future.

[0140] The present invention also provides a device for determining the grid frequency change rate measurement window, which can be used to execute the method for determining the grid frequency change rate measurement window described in any one of the above embodiments of the present invention.

[0141] Please refer to Figure 2 , Figure 2 which shows the structural connection block diagram of a device for determining the grid frequency change rate measurement window provided by an embodiment of the present invention.

[0142] A device for determining the grid frequency change rate measurement window provided by an embodiment of the present invention includes:

[0143] The first determination module 1 is used to determine the total system kinetic energy of the target grid under the target operation mode; the target operation mode is the operation mode corresponding to the minimum system moment of inertia of the target grid;

[0144] The second determination module 2 is used to determine the typical N-2 faults of the target grid under the target operation mode to obtain a target fault set;

[0145] The third determination module 3 is configured to determine the unbalanced power of the system after each target fault occurs; the target fault is a fault in the target fault set.

[0146] The calculation module 4 is configured to calculate the system frequency change rate corresponding to the corresponding target fault according to the unbalanced power and the total kinetic energy of the system, and obtain the theoretical value of the system frequency change rate corresponding to each target fault.

[0147] The fourth determination module 5 is configured to determine each frequency change rate measurement point distributed in the key areas of the target power grid, and obtain the target frequency change rate measurement point set.

[0148] The first construction module 6 is configured to construct target constraint conditions for the measurement parameter values of different target frequency change rate measurement points corresponding to each target fault under different frequency change rate measurement window values; the target frequency change rate measurement point is a frequency change rate measurement point in the target frequency change rate measurement point set; the measurement parameter value includes the maximum value of the frequency change rate measurement value and the frequency change rate measurement deviation during the period when the target fault occurs; the target frequency change rate measurement point is a frequency change rate measurement point in the target frequency change rate measurement point set; the target constraint conditions include: the frequency change rate measurement window value is between the preset window initial value and the preset window maximum allowable value, the maximum value of all frequency change rate measurement deviations is not greater than the frequency change rate measurement deviation fixed value, and the maximum value of each frequency change rate measurement value is not greater than the corresponding theoretical value of the system frequency change rate.

[0149] The second construction module 7 is configured to use minimizing the frequency change rate measurement window as the objective function, and establish a frequency change rate measurement window optimization model according to the objective function and the target constraint conditions.

[0150] The solution module 8 is configured to optimize and solve the frequency change rate measurement window optimization model, and obtain and output the optimal frequency change rate measurement window.

[0151] In an implementable manner, the first determination module 1 includes:

[0152] The determination unit is configured to determine the target operation mode of the target power grid by using minimizing the number of synchronized generator units in operation, maximizing the total output of new energy generator units, and minimizing the inertia constant of the synchronized generator units as the constraint conditions of the operation mode.

[0153] The first calculation unit is configured to calculate the total kinetic energy of the system of the target power grid in the target operation mode.

[0154] In an implementable manner, the first calculation unit is specifically configured to:

[0155] Calculate the total kinetic energy of the system of the target power grid in the target operation mode according to the following formula:

[0156] E sys = E SG + E IM + E V ( VS ) + E V ( CS ) + E Load

[0157] In the formula, E sys represents the total system kinetic energy of the target power grid under the target operation mode, E SG represents the total kinetic energy of the synchronous generator sets, E IM represents the total kinetic energy of the asynchronous induction motors, E V(VS) represents the energy form of the voltage source type virtual inertia, E V(CS) represents the energy form of the current source type virtual inertia, E Load represents the energy form of the equivalent inertia of the static load voltage.

[0158] In an implementable manner, the calculation module 4 includes:

[0159] A second calculation unit, configured to calculate the system frequency change rate corresponding to each target fault according to the following formula:

[0160]

[0161] In the formula, RoCoF theory (i) is the system frequency change rate corresponding to the target fault i, f0 is the system rated frequency, ΔP i is the unbalanced power of the system after the occurrence of the target fault i, E sys is the total system kinetic energy of the target power grid under the target operation mode.

[0162] In an implementable manner, in the target constraint condition, the occurrence moment of the target fault is used as the lower bound of the occurrence period of the target fault, and the sum of the occurrence moment of the target fault and the preset fault time factor is used as the upper bound of the occurrence period of the target fault.

[0163] In an implementable manner, the second construction module 7 includes:

[0164] A model establishment unit, configured to establish an optimized model for the frequency change rate measurement window as:

[0165]

[0166] s.t.

[0167] T0 ≤ T ≤ T max

[0168] max{[max(RoCoF i,j,T (t)) - min(RoCoF i,j,T (t)), t ∈ [t0, t0 + τ]], i ∈ Ω F , j ∈ Ω M} ≤ ∈

[0169] max{RoCoF i,j,T (t), t ∈ [t0, t0 + τ]} ≤ RoCoF theory (i)

[0170] Wherein, T represents the frequency change rate measurement window value, T0 represents the initial value of the preset window, T max represents the maximum allowable value of the preset window, Ω F represents the target fault set, Ω M represents the set of target frequency change rate measurement points, RoCoF i,j,T (t) represents the frequency change rate measurement value at time t within the occurrence period of the target fault for the measurement point j corresponding to the target fault i at the frequency change rate measurement window value of T, t0 is the occurrence time of the target fault, τ is the preset fault time factor, RoCoF theory (i) is the system frequency change rate corresponding to the target fault i, and ∈ is the fixed value of the frequency change rate measurement deviation.

[0171] In an implementable manner, the solving module 8 includes:

[0172] A solving unit, configured to solve the frequency change rate measurement window optimization model by gradually increasing the frequency change rate measurement window value.

[0173] The present invention also provides a device for determining a power grid frequency change rate measurement window, including:

[0174] A memory, configured to store instructions; wherein, the instructions are used to implement the power grid frequency change rate measurement window determination method described in any one of the above embodiments;

[0175] A processor, configured to execute the instructions in the memory.

[0176] The present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the power grid frequency change rate measurement window determination method described in any one of the above embodiments.

[0177] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the devices and modules described above can refer to the corresponding processes in the foregoing method embodiments, and the specific beneficial effects of the devices and modules described above can refer to the corresponding beneficial effects in the foregoing method embodiments, which will not be elaborated herein.

[0178] In several embodiments provided by the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules is only a logical function division. In actual implementation, there may be other division methods. For example, multiple modules or components can be combined or integrated into another device, or some features can be ignored or not executed.

[0179] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they can be located in one place or distributed to multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0180] In addition, in each embodiment of the present invention, the functional modules can be integrated into one processing module, or each module can exist physically alone, or two or more modules can be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software functional modules.

[0181] If the above-mentioned integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0182] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for determining a measurement window of the power grid frequency change rate, characterized in that, Including: Determine the total system kinetic energy of the target power grid under the target operating mode; The target operating mode is the operating mode corresponding to the minimum system moment of inertia of the target power grid; Determine the typical N-2 faults of the target power grid under the target operating mode to obtain a target fault set; Determine the unbalanced power of the system after each target fault occurs; The target fault is a fault in the target fault set; Calculate the system frequency change rate corresponding to the corresponding target fault according to the unbalanced power and the total system kinetic energy to obtain the theoretical value of the system frequency change rate corresponding to each target fault; Determine each frequency change rate measurement point spread over the key areas of the target power grid to obtain a target frequency change rate measurement point set; Construct target constraint conditions for the measurement parameter values of different target frequency change rate measurement points corresponding to each target fault under different frequency change rate measurement window values; the target frequency change rate measurement point is the frequency change rate measurement point in the target frequency change rate measurement point set; the measurement parameter values include the maximum value of the frequency change rate measurement value and the frequency change rate measurement deviation during the target fault occurrence period; The target frequency change rate measurement point is the frequency change rate measurement point in the target frequency change rate measurement point set; the target constraint conditions include: the frequency change rate measurement window value is between the preset window initial value and the maximum allowable value of the preset window, the maximum value of all frequency change rate measurement deviations is not greater than the frequency change rate measurement deviation fixed value, and the maximum value of each frequency change rate measurement value is not greater than the corresponding theoretical value of the system frequency change rate; Take minimizing the frequency change rate measurement window as the objective function, and establish a frequency change rate measurement window optimization model according to the objective function and the target constraint conditions; Optimize and solve the frequency change rate measurement window optimization model to obtain and output the optimal frequency change rate measurement window; The establishment of the frequency change rate measurement window optimization model according to the objective function and the target constraint conditions includes: Establish the frequency change rate measurement window optimization model as: ； In the formula, represents the frequency change rate measurement window value, represents the initial value of the preset window, represents the maximum allowable value of the preset window, represents the target fault set, represents the set of target frequency change rate measurement points, represents the target fault corresponding frequency change rate measurement point at the time when the frequency change rate measurement window value is during the occurrence period of the target fault frequency change rate measurement value at the moment, is the occurrence time of the target fault, is the preset fault time factor, is the target fault corresponding system frequency change rate, is the fixed value of the frequency change rate measurement deviation.

2. The method for determining the power grid frequency change rate measurement window according to claim 1, wherein The determination of the total system kinetic energy of the target power grid under the target operating mode includes: Taking the minimization of the number of synchronized generator units in operation, the maximization of the total output of new energy generator units, and the minimization of the inertia constant of synchronized generator units as the constraint conditions of the operating mode, determine the target operating mode of the target power grid; Calculate the total system kinetic energy of the target power grid under the target operating mode.

3. The method for determining the power grid frequency change rate measurement window according to claim 2, wherein, The calculation of the total system kinetic energy of the target power grid under the target operating mode includes: Calculate the total system kinetic energy of the target power grid under the target operating mode according to the following formula: ； In the formula, represents the total system kinetic energy of the target power grid under the target operation mode, represents the total kinetic energy of the synchronous generator sets, represents the total kinetic energy of the asynchronous induction motors, represents the energy form of the voltage-source type virtual inertia, represents the energy form of the current-source type virtual inertia, represents the energy form of the static load voltage equivalent inertia.

4. The method for determining the power grid frequency change rate measurement window according to claim 1, wherein The calculation of the system frequency change rate corresponding to the corresponding target fault according to the unbalanced power and the total system kinetic energy to obtain the theoretical value of the system frequency change rate corresponding to each target fault includes: Calculate the system frequency change rate corresponding to each target fault according to the following formula: ； In the formula, is the target fault corresponding system frequency change rate, is the system rated frequency, is the target fault unbalanced power of the system after the occurrence, is the total system kinetic energy of the target power grid under the target operation mode.

5. The method for determining the power grid frequency change rate measurement window according to claim 1, characterized in that In the target constraint conditions, the occurrence time of the target fault is used as the lower bound of the target fault occurrence period, and the sum of the occurrence time of the target fault and the preset fault time factor is used as the upper bound of the target fault occurrence period.

6. The method for determining the power grid frequency change rate measurement window according to claim 1, wherein Optimizing and solving the optimized model of the frequency change rate measurement window includes: Solving the optimized model of the frequency change rate measurement window by gradually increasing the value of the frequency change rate measurement window.

7. A device for determining a measurement window of the power grid frequency change rate, characterized in that, Including: A first determination module for determining the total system kinetic energy of the target power grid under the target operating mode; The target operating mode is the operating mode corresponding to the minimum system moment of inertia of the target power grid; A second determination module for determining typical N-2 faults of the target power grid under the target operating mode to obtain a target fault set; A third determination module for determining the unbalanced power of the system after each target fault occurs; The target fault is a fault in the target fault set; A calculation module for calculating the system frequency change rate corresponding to the corresponding target fault according to the unbalanced power and the total system kinetic energy to obtain the theoretical values of the system frequency change rates corresponding to each target fault; A fourth determination module for determining each frequency change rate measurement point distributed in the key areas of the target power grid to obtain a target frequency change rate measurement point set; A first construction module for constructing target constraint conditions for the measurement parameter values of each target frequency change rate measurement point corresponding to each target fault under different frequency change rate measurement window values; the target frequency change rate measurement point is the frequency change rate measurement point in the target frequency change rate measurement point set; the measurement parameter values include the maximum value of the frequency change rate measurement value and the frequency change rate measurement deviation during the period when the target fault occurs; The target frequency change rate measurement point is the frequency change rate measurement point in the target frequency change rate measurement point set; the target constraint conditions include: the frequency change rate measurement window value is between the preset window initial value and the maximum allowable value of the preset window, the maximum value of all frequency change rate measurement deviations is not greater than the fixed value of the frequency change rate measurement deviation, and the maximum value of each frequency change rate measurement value is not greater than the corresponding theoretical value of the system frequency change rate; A second construction module for establishing an optimized model of the frequency change rate measurement window with minimizing the frequency change rate measurement window as the objective function according to the objective function and the target constraint conditions; A solving module for optimizing and solving the optimized model of the frequency change rate measurement window to obtain and output the optimal frequency change rate measurement window; The second construction module includes: A model establishment unit for establishing the optimized model of the frequency change rate measurement window as: ； Wherein, represents the frequency change rate measurement window value, represents the initial value of the preset window, represents the maximum allowable value of the preset window, represents the target fault set, represents the set of target frequency change rate measurement points, represents the target fault corresponding to the frequency change rate measurement point at the time when the frequency change rate measurement window value is during the occurrence period of the target fault the frequency change rate measurement value at the moment, is the occurrence time of the target fault, is the preset fault time factor, is the target fault corresponding system frequency change rate, is the fixed value of the frequency change rate measurement deviation.

8. A device for determining a measurement window of the power grid frequency change rate, characterized in that, Including: A memory for storing instructions; wherein, the instructions are used to implement the method for determining the frequency change rate measurement window of the power grid according to any one of claims 1-6; A processor for executing the instructions in the memory.

9. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, and when the computer program is executed by the processor, the method for determining the frequency change rate measurement window of the power grid according to any one of claims 1-6 is implemented.

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