Nuclear power primary frequency modulation power smoothing control method and system based on super capacitor

Abstract

The application provides a supercapacitor-based nuclear power primary frequency modulation power smoothing control method and system, relates to the technical field of nuclear power unit frequency modulation control, and comprises the following steps: performing time-frequency domain analysis on a target frequency modulation power sequence, extracting power change rate and duration characteristics, combining reactor thermal inertia and control rod adjustment delay characteristics, predicting the power response boundary of the nuclear power unit, decomposing the target frequency modulation power into a nuclear power unit bearing component and a supercapacitor compensation component, and adjusting the distribution of the two components under the constraint of the energy margin of the supercapacitor, so as to smooth the power output curve of the nuclear power unit and improve the primary frequency modulation capacity of the nuclear power unit and reduce the thermal stress and safety risk of the unit.

Description

Technical Field

[0001] This invention relates to the field of frequency regulation control technology for nuclear power units, and in particular to a method and system for smoothing primary frequency regulation power control of nuclear power units based on supercapacitors. Background Technology

[0002] With the increasing demand for clean energy in power systems, nuclear power, as an important baseload power source, is receiving increasing attention for its primary frequency regulation capabilities. Nuclear power units participating in grid frequency regulation can improve the stability and reliability of the grid. Currently, nuclear power units mainly regulate reactor power by moving control rods, thereby achieving power regulation in response to grid frequency changes.

[0003] During grid frequency regulation, nuclear power units face challenges such as slow response and limited regulation capabilities due to their unique thermal characteristics and control mechanisms. Traditional primary frequency regulation control methods for nuclear power plants mainly rely on control rod systems, adjusting reactor power by changing the position of the control rods. However, this method has significant limitations. As the grid's requirements for frequency regulation capabilities increase, relying solely on the nuclear power unit's own regulation capabilities is no longer sufficient to meet the grid's demand for rapid response.

[0004] Traditional nuclear power plant primary frequency regulation control methods fail to fully consider the reactor's thermal inertia characteristics and control rod regulation delay characteristics. This results in nuclear power units struggling to respond promptly to rapidly changing frequency disturbances, failing to meet the grid's requirements for rapid frequency regulation. Existing nuclear power plant frequency regulation control strategies lack time-frequency domain characteristic analysis of frequency regulation power demand, making it impossible to implement targeted control based on power change rate and duration characteristics. This makes nuclear power units prone to over-response or under-response during frequency regulation. Although some research has applied energy storage devices to nuclear power plant frequency regulation systems, the lack of reasonable power allocation strategies and insufficient consideration of supercapacitor energy capacity limitations leads to supercapacitor energy depletion under prolonged or large-amplitude frequency regulation demands, preventing the continuous and effective power compensation and impacting overall frequency regulation performance. Summary of the Invention

[0005] The present invention provides a method and system for smoothing the primary frequency regulation power control of nuclear power plants based on supercapacitors, which can solve the problems in the prior art.

[0006] A first aspect of the present invention provides a method for smoothing the primary frequency regulation power control of nuclear power plants based on supercapacitors, comprising:

[0007] The target frequency regulation power demand is calculated based on the current operating status parameters of the nuclear power unit and the frequency deviation of the power grid, and the target frequency regulation power sequence is obtained.

[0008] A joint time-frequency domain analysis is performed on the target frequency-modulated power sequence to extract the power change rate characteristics and power duration characteristics of the target frequency-modulated power sequence. Combined with the reactor thermal inertia characteristics and control rod regulation delay characteristics in the current operating state parameters, the power response boundary of the core generator unit in the future time window is predicted.

[0009] The target frequency modulation power sequence is decomposed into a power component borne by the nuclear power unit and a power component compensated by the supercapacitor. The power component compensated by the supercapacitor includes the power demand segment in the target frequency modulation power sequence that exceeds the power response boundary.

[0010] Based on the power amplitude and duration requirements of the supercapacitor compensation power component, an energy margin constraint condition for the supercapacitor is constructed, and the power demand of the supercapacitor compensation power component exceeding the energy margin constraint condition is transferred to the nuclear power unit to bear the power component.

[0011] The power ramp rate of the power component undertaken by the nuclear power unit is adjusted, and the power fluctuation of the adjusted nuclear power unit is compensated in real time by using the adjusted supercapacitor to smooth the power output curve of the nuclear power unit.

[0012] Based on the current operating parameters of the nuclear power unit and the frequency deviation from the power grid, the target frequency regulation power demand is calculated, resulting in the following target frequency regulation power sequence:

[0013] Collect reactor power level, primary coolant temperature, steam generator pressure, control rod position, and grid frequency deviation signals of the nuclear power unit;

[0014] Based on the grid frequency deviation signal and the preset primary frequency regulation control strategy, the initial frequency regulation power requirement that the nuclear power unit should output is calculated.

[0015] The current power operating margin is calculated based on the reactor power level and the rated power of the nuclear power unit; the thermal margin is calculated based on the primary coolant temperature and the safe operating temperature limit; the control margin is calculated based on the control rod position and the control rod stroke limit; and the pressure margin is calculated based on the steam generator pressure and the pressure safety boundary.

[0016] The minimum value among the power operating margin, the thermal margin, the control margin, and the pressure margin is determined as the current adjustable power margin of the nuclear power unit.

[0017] When the initial frequency regulation power demand exceeds the adjustable power margin, the initial frequency regulation power demand is reduced to the value of the adjustable power margin to generate a corrected frequency regulation power demand that meets the safe operation boundary of the nuclear power unit.

[0018] The modified frequency modulation power demand is discretized along the time axis according to a preset time sampling interval. The power demand value corresponding to each sampling moment is calculated to form the target frequency modulation power sequence containing power demand values ​​at multiple moments.

[0019] Performing joint time-frequency domain analysis on the target frequency-modulated power sequence to extract the power change rate characteristics and power duration characteristics of the target frequency-modulated power sequence includes:

[0020] The target frequency-modulated power sequence is decomposed by wavelet to obtain multiple wavelet coefficient sequences of different frequency bands. The energy proportion of the wavelet coefficient sequence of each frequency band is calculated. The wavelet coefficient sequence corresponding to the frequency band with the energy proportion greater than the preset energy threshold is reconstructed into a high-frequency power fluctuation component. The remaining wavelet coefficient sequences are reconstructed into a low-frequency power trend component.

[0021] The high-frequency power fluctuation component is subjected to modulus maxima detection, and the time corresponding to the obtained modulus maxima is marked as a power abrupt change point; the amplitude of the modulus maxima is used as the power change amplitude at the power abrupt change point; the difference between the power change rate before and after the power abrupt change point is calculated as the jump variable of the power change rate between the two time points; the time position of the power abrupt change point, the power change amplitude, and the jump variable are combined to form the power change rate feature;

[0022] Zero-crossing point detection and extreme point detection are performed on the low-frequency power trend component to identify the power inflection points in the target frequency modulation power sequence where the power demand changes from rising to falling or from falling to rising. The time interval between adjacent power inflection points is calculated as the duration of the monotonic power change. Frequency statistics and probability distribution fitting are performed on the duration of the monotonic power change to obtain the power duration feature.

[0023] Based on the reactor thermal inertia characteristics and control rod regulation delay characteristics in the current operating state parameters, the predicted power response boundaries of the core generator unit in the future time window include:

[0024] Based on the primary coolant temperature and reactor power level in the current operating status parameters, the response time constant of the primary coolant temperature to power change is calculated, and the response time constant of the steam generator pressure to power change is calculated based on the steam generator pressure and reactor power level. The two response time constants are used as the reactor thermal inertial characteristics.

[0025] Based on the control rod position and control rod movement speed limits in the current operating state parameters, the control rod position adjustment delay is calculated, and the control rod responsiveness adjustment delay is calculated based on the control rod responsiveness value curve. The control rod position adjustment delay and the control rod responsiveness adjustment delay are used as control rod adjustment delay features.

[0026] The reactor thermal inertial characteristics and the control rod regulation delay characteristics are coupled and calculated to determine the comprehensive response delay time required for the nuclear power unit to reach the target power level from receiving the power demand command.

[0027] Based on the reactor power level and adjustable power margin in the current operating status parameters, and combined with the comprehensive response delay time, the maximum power increase and maximum power decrease that the nuclear power unit can achieve at each moment in the future time window are calculated, and the power response boundary of the nuclear power unit in the future time window is obtained.

[0028] The target frequency-modulated power sequence is decomposed into a power component supplied by nuclear power units and a power component compensated by supercapacitors. The supercapacitor-compensated power component includes power demand segments in the target frequency-modulated power sequence that exceed the power response boundary, including:

[0029] Traverse each moment within the future time window of the target frequency modulation power sequence, compare the power demand value at each moment with the power response boundary at the corresponding moment, calculate the difference between the power demand value and the maximum power increase and the maximum power decrease as the power increase gap and the power decrease gap respectively, and mark the moment with the power increase gap or the power decrease gap and the corresponding power gap value as the power demand segment.

[0030] For the power demand segment, the upward or downward power gap at each moment is taken as the power value that the supercapacitor needs to compensate at the corresponding moment and combined in time order to form the supercapacitor compensation power component.

[0031] For moments in the target frequency modulation power sequence that do not exceed the power response boundary, the power demand value at the corresponding moment is directly used as the power value undertaken by the nuclear power unit at the corresponding moment; for each moment in the power demand segment that exceeds the power response boundary, the maximum power increase or the maximum power decrease at the corresponding moment is used as the power value undertaken by the nuclear power unit at the corresponding moment; the power values ​​undertaken by the nuclear power unit at each moment are combined in chronological order to form the power component undertaken by the nuclear power unit.

[0032] Based on the power amplitude and duration requirements of the supercapacitor's compensation power component, the energy margin constraints for the supercapacitor are constructed as follows:

[0033] Iterate through the supercapacitor compensation power component at each moment within the future time window, extract the power value that the supercapacitor needs to compensate at each moment as the instantaneous power demand and calculate the absolute value as the power amplitude, and count the time span of the continuous compensation power in the supercapacitor compensation power component as the duration demand.

[0034] Based on the power amplitude and the duration requirement, calculate the energy value required for the supercapacitor to accumulate discharge or charge at each moment in the future time window, and take the maximum value of the accumulated energy value in the future time window as the maximum energy requirement of the supercapacitor.

[0035] Based on the current state of charge and rated energy capacity of the supercapacitor, the current available energy reserve of the supercapacitor is calculated. When the maximum energy demand exceeds the current available energy reserve, the difference between the maximum energy demand and the current available energy reserve is calculated as the energy gap.

[0036] Based on the energy gap and the instantaneous power demand of the supercapacitor's compensation power component at each moment within the future time window, a constraint condition is constructed that the state of charge of the supercapacitor at each moment within the future time window must be within the allowable range of the rated energy capacity, which serves as the energy margin constraint condition for the supercapacitor.

[0037] Adjusting the power ramp rate of the power component undertaken by the nuclear power unit, and using the adjusted supercapacitor to compensate for the power component to perform real-time compensation for power fluctuations in the adjusted power component undertaken by the nuclear power unit, includes:

[0038] Using the constraints of nuclear power unit power ramp-up rate and supercapacitor energy margin as boundary conditions, the power value of the power component undertaken by the nuclear power unit at each time within a future time window is optimized and redistributed. Within the boundary conditions, with the goal of minimizing the fluctuation of nuclear power unit power ramp-up rate, the optimal power sharing ratio between the nuclear power unit and the supercapacitor at each time is calculated.

[0039] The power sequence undertaken by the nuclear power units after the optimized redistribution is taken as the adjusted power component undertaken by the nuclear power units, and the power sequence newly undertaken by the supercapacitors after the optimized redistribution is superimposed on the supercapacitor compensation power component to form the adjusted supercapacitor compensation power component.

[0040] Based on the deviation sequence between the adjusted nuclear power unit's power component and the actual power output value of the nuclear power unit, the frequency domain characteristics and time domain evolution law of the deviation sequence are extracted. The amplitude and phase of the nuclear power unit's power fluctuation in the future period are predicted using the frequency domain characteristics and time domain evolution law, and the corresponding power deviation prediction value is calculated. The power deviation prediction value is superimposed on the adjusted supercapacitor compensation power component to generate a supercapacitor feedforward compensation command.

[0041] A second aspect of the present invention provides a nuclear power primary frequency regulation power smoothing control system based on a supercapacitor, comprising:

[0042] The first unit is used to calculate the target frequency regulation power demand based on the current operating status parameters of the nuclear power unit and the deviation of the grid frequency, and to obtain the target frequency regulation power sequence.

[0043] The second unit is used to perform joint time-frequency domain analysis on the target frequency-modulated power sequence, extract the power change rate characteristics and power duration characteristics of the target frequency-modulated power sequence, and combine the reactor thermal inertia characteristics and control rod regulation delay characteristics in the current operating state parameters to predict the power response boundary of the core generator unit in the future time window.

[0044] The third unit is used to decompose the target frequency modulation power sequence into a nuclear power unit-borne power component and a supercapacitor-compensated power component, wherein the supercapacitor-compensated power component includes the power demand segment in the target frequency modulation power sequence that exceeds the power response boundary.

[0045] The fourth unit is used to construct the energy margin constraint condition of the supercapacitor based on the power amplitude and duration requirement of the supercapacitor compensation power component, and transfer the power requirement of the supercapacitor compensation power component that exceeds the energy margin constraint condition to the nuclear power unit to bear the power component.

[0046] The fifth unit is used to adjust the power ramp rate of the power component undertaken by the nuclear power unit, and to use the adjusted supercapacitor to compensate for the power fluctuation of the adjusted power component undertaken by the nuclear power unit in real time, thereby smoothing the power output curve of the nuclear power unit.

[0047] A third aspect of the embodiments of the present invention,

[0048] An electronic device is provided, comprising:

[0049] processor;

[0050] Memory used to store processor-executable instructions;

[0051] The processor is configured to invoke instructions stored in the memory to execute the aforementioned method.

[0052] Fourth aspect of the present invention,

[0053] A computer-readable storage medium is provided, having stored thereon computer program instructions that, when executed by a processor, implement the aforementioned method.

[0054] The beneficial effects of this application are as follows:

[0055] By jointly analyzing the target frequency regulation power sequence in the time and frequency domains, and combining the reactor thermal inertia characteristics with the control rod regulation delay characteristics, accurate prediction of the power response boundary of nuclear power units was achieved, effectively avoiding the problem of insufficient consideration of the dynamic characteristics of nuclear power units in traditional methods. The target frequency regulation power sequence was innovatively decomposed into the nuclear power unit-borne portion and the supercapacitor-compensated portion, enabling accurate identification and compensation of sections exceeding the nuclear power unit's response capacity, thus improving the response speed and regulation accuracy of nuclear power participation in grid frequency regulation. By constructing supercapacitor energy margin constraints and optimizing power allocation, the problem of limited supercapacitor energy storage was solved, ensuring the sustainable operation of energy storage equipment during long-term frequency regulation and enhancing system stability. Attached Figure Description

[0056] Figure 1 This is a flowchart illustrating the nuclear power primary frequency regulation power smoothing control method based on supercapacitors according to an embodiment of the present invention.

[0057] Figure 2 This is a schematic diagram of the feature extraction process for the target frequency-modulated power sequence. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0059] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0060] Figure 1 This is a flowchart illustrating the nuclear power primary frequency regulation power smoothing control method based on supercapacitors according to an embodiment of the present invention. Figure 1 As shown, the method includes:

[0061] The target frequency regulation power demand is calculated based on the current operating status parameters of the nuclear power unit and the frequency deviation of the power grid, and the target frequency regulation power sequence is obtained.

[0062] A joint time-frequency domain analysis is performed on the target frequency-modulated power sequence to extract the power change rate characteristics and power duration characteristics of the target frequency-modulated power sequence. Combined with the reactor thermal inertia characteristics and control rod regulation delay characteristics in the current operating state parameters, the power response boundary of the core generator unit in the future time window is predicted.

[0063] The target frequency modulation power sequence is decomposed into a power component borne by the nuclear power unit and a power component compensated by the supercapacitor. The power component compensated by the supercapacitor includes the power demand segment in the target frequency modulation power sequence that exceeds the power response boundary.

[0064] Based on the power amplitude and duration requirements of the supercapacitor compensation power component, an energy margin constraint condition for the supercapacitor is constructed, and the power demand of the supercapacitor compensation power component exceeding the energy margin constraint condition is transferred to the nuclear power unit to bear the power component.

[0065] The power ramp rate of the power component undertaken by the nuclear power unit is adjusted, and the power fluctuation of the adjusted nuclear power unit is compensated in real time by using the adjusted supercapacitor to smooth the power output curve of the nuclear power unit.

[0066] In one optional implementation, the target frequency regulation power demand is calculated based on the current operating status parameters of the nuclear power unit and the grid frequency deviation, resulting in a target frequency regulation power sequence including:

[0067] Collect reactor power level, primary coolant temperature, steam generator pressure, control rod position, and grid frequency deviation signals of the nuclear power unit;

[0068] Based on the grid frequency deviation signal and the preset primary frequency regulation control strategy, the initial frequency regulation power requirement that the nuclear power unit should output is calculated.

[0069] The current power operating margin is calculated based on the reactor power level and the rated power of the nuclear power unit; the thermal margin is calculated based on the primary coolant temperature and the safe operating temperature limit; the control margin is calculated based on the control rod position and the control rod stroke limit; and the pressure margin is calculated based on the steam generator pressure and the pressure safety boundary.

[0070] The minimum value among the power operating margin, the thermal margin, the control margin, and the pressure margin is determined as the current adjustable power margin of the nuclear power unit.

[0071] When the initial frequency regulation power demand exceeds the adjustable power margin, the initial frequency regulation power demand is reduced to the value of the adjustable power margin to generate a corrected frequency regulation power demand that meets the safe operation boundary of the nuclear power unit.

[0072] The modified frequency modulation power demand is discretized along the time axis according to a preset time sampling interval. The power demand value corresponding to each sampling moment is calculated to form the target frequency modulation power sequence containing power demand values ​​at multiple moments.

[0073] Key operating parameters of nuclear power units are collected, including reactor power level, primary coolant temperature, steam generator pressure, control rod position, and grid frequency deviation signal. These parameters can be acquired in real time through the nuclear power plant's digital instrumentation and control system (DCS), with a sampling frequency typically once per second to ensure the timeliness and accuracy of the data.

[0074] Based on the collected grid frequency deviation signal, when the grid frequency is higher than the nominal frequency (e.g., 50Hz), the nuclear power unit needs to reduce its output; when the grid frequency is lower than the nominal frequency, the nuclear power unit needs to increase its output. The initial frequency regulation power requirement can be calculated by multiplying the grid frequency deviation value by a preset frequency regulation coefficient. For example, when the grid frequency deviation is -0.1Hz and the frequency regulation coefficient is 5% of the rated power / Hz, the initial frequency regulation power requirement is 0.5% of the nuclear power unit's rated power.

[0075] Calculating the current power operating margin based on reactor power level and rated power: Extract the reactor power level P_reactor and the nuclear power unit's rated power P_rated from the collected real-time data. Calculate the difference between the two to obtain the power deviation ΔP = P_rated - P_reactor. Then, divide the power deviation ΔP by the rated power P_rated to obtain the power deviation percentage η_power = ΔP / P_rated. Multiply the power deviation percentage η_power by the rated power P_rated to obtain the power operating margin M_power = η_power × P_rated. Assuming the nuclear power unit's rated power is 1000MW and the current reactor power is 950MW, the power operating margin is 50MW, which is 5% of the rated power.

[0076] The thermal margin is calculated based on the primary coolant temperature and the safe operating temperature limit: The current primary coolant temperature T_coolant and the preset safe operating temperature limit T_limit are extracted from the collected real-time data. The difference between the two is calculated to obtain the temperature margin ΔT = T_limit - T_coolant. Using a pre-calibrated temperature-to-power conversion coefficient k_temp (representing the power change corresponding to a 1°C temperature change), the temperature margin ΔT is multiplied by the temperature-to-power conversion coefficient k_temp to obtain the thermal margin M_thermal = ΔT × k_temp. For example, if the current primary coolant temperature is 315°C and the safe operating temperature limit is 325°C, based on the temperature-to-power correspondence (assuming a 2% increase in rated power for every 1°C increase), the thermal margin is the power change corresponding to 10°C, i.e., 20% of the rated power.

[0077] The control margin is calculated based on the control rod position and travel limit: The current position percentage H_rod of the control rod assembly and the preset safe operating lower limit position percentage H_limit are extracted from the collected real-time data. The difference between the two is calculated to obtain the available travel percentage ΔH = H_rod - H_limit. According to the pre-calibrated control rod travel-power conversion coefficient k_rod (representing the power change corresponding to a 1% change in control rod position), the available travel percentage ΔH is multiplied by the control rod travel-power conversion coefficient k_rod to obtain the control margin M_control = ΔH × k_rod. If the current control rod assembly is at 60% of its travel and the safe operating lower limit is 10%, then the control rod insertion margin is 50% of its travel. Based on the correspondence between control rod position and power (assuming that a 1% downward movement of the control rod corresponds to a 0.5% reduction in rated power), the control margin is 25% of the rated power.

[0078] The pressure margin is calculated based on the steam generator pressure and the pressure safety boundary: The current steam generator pressure P_steam and the preset pressure safety upper limit P_boundary are extracted from the collected real-time data. The difference between the two is calculated to obtain the pressure margin ΔP_steam = P_boundary - P_steam. According to the pre-calibrated pressure-power conversion coefficient k_pressure (representing the power change corresponding to each unit pressure change), the pressure margin ΔP_steam is multiplied by the pressure-power conversion coefficient k_pressure to obtain the pressure margin M_pressure = ΔP_steam × k_pressure. If the current steam generator pressure is 6.8 MPa and the pressure upper limit is 7.1 MPa, based on the correspondence between pressure and power (assuming that each 0.1 MPa increase corresponds to a 3% increase in rated power), the pressure margin is 9% of the rated power.

[0079] The minimum value among the above four margins (power operation margin 5%, thermal margin 20%, control margin 25%, and pressure margin 9%) is determined as the current adjustable power margin of the nuclear power unit, i.e., 5% of the rated power.

[0080] When the initial frequency regulation power demand exceeds the adjustable power margin, a power demand correction is required. Taking the example above, if the initial frequency regulation power demand is 7% of the rated power, while the adjustable power margin is only 5%, then the initial frequency regulation power demand is reduced to 5% of the rated power, forming the corrected frequency regulation power demand. This correction ensures that the frequency regulation demand is met without exceeding the safe operating limits of the nuclear power unit.

[0081] The corrected frequency regulation power demand is discretized along the time axis according to a preset time sampling interval (e.g., 5 seconds) to generate a target frequency regulation power sequence. Specifically, assuming the corrected frequency regulation power demand at the initial time t0 is 5% of the rated power, i.e., 50MW, then the target frequency regulation power value at time t0 is 50MW; as time progresses and the grid frequency changes, at time t0+5 seconds, the parameters are re-evaluated and the corrected frequency regulation power demand is calculated to be 45MW, then the target frequency regulation power value at that time is 45MW. This process is repeated cyclically to form a target frequency regulation power sequence containing power demand values ​​at multiple times, such as [50MW, 45MW, 48MW, …].

[0082] The above implementation method enables effective regulation of the power grid frequency while ensuring the safe and stable operation of nuclear power units, thereby improving the stability and reliability of the power system. This method fully considers various operating parameters and safety limitations of nuclear power units, ensuring that the frequency regulation process will not adversely affect the safe operation of the nuclear power units.

[0083] In one optional implementation, performing joint time-frequency domain analysis on the target frequency-modulated power sequence to extract the power change rate characteristics and power duration characteristics of the target frequency-modulated power sequence includes:

[0084] The target frequency-modulated power sequence is decomposed by wavelet to obtain multiple wavelet coefficient sequences of different frequency bands. The energy proportion of the wavelet coefficient sequence of each frequency band is calculated. The wavelet coefficient sequence corresponding to the frequency band with the energy proportion greater than the preset energy threshold is reconstructed into a high-frequency power fluctuation component. The remaining wavelet coefficient sequences are reconstructed into a low-frequency power trend component.

[0085] The high-frequency power fluctuation component is subjected to modulus maxima detection, and the time corresponding to the obtained modulus maxima is marked as a power abrupt change point; the amplitude of the modulus maxima is used as the power change amplitude at the power abrupt change point; the difference between the power change rate before and after the power abrupt change point is calculated as the jump variable of the power change rate between the two time points; the time position of the power abrupt change point, the power change amplitude, and the jump variable are combined to form the power change rate feature;

[0086] Zero-crossing point detection and extreme point detection are performed on the low-frequency power trend component to identify the power inflection points in the target frequency modulation power sequence where the power demand changes from rising to falling or from falling to rising. The time interval between adjacent power inflection points is calculated as the duration of the monotonic power change. Frequency statistics and probability distribution fitting are performed on the duration of the monotonic power change to obtain the power duration feature.

[0087] like Figure 2 As shown, the method includes:

[0088] Discrete wavelet transform is used to decompose the target frequency-modulated power sequence into wavelet coefficient sequences of multiple different frequency bands. Specifically, by selecting an appropriate discrete wavelet transform and a decomposition level N (usually 3 to 5 levels), the target frequency-modulated power sequence is decomposed into a multi-scale decomposition, resulting in an approximate coefficient sequence and N detail coefficient sequences.

[0089] Calculate the energy proportion of wavelet coefficient sequences in each frequency band. For each level of detail coefficient sequence dj and approximate coefficient sequence aN, calculate the ratio of its energy Ej to the total energy Etotal, i.e., energy proportion Pj = Ej / Etotal. Energy calculation uses the sum of squares of coefficients, i.e., Ej = Σ|coeffj,k| 2 , where coeffj,k is the k-th wavelet coefficient of the j-th layer.

[0090] The importance of each frequency band is determined based on a preset energy threshold (usually set between 0.1 and 0.3). The wavelet coefficient sequences corresponding to frequency bands with an energy proportion greater than the preset energy threshold are reconstructed into high-frequency power fluctuation components using a wavelet reconstruction algorithm, representing the abrupt changes and fluctuations in the power sequence; the remaining wavelet coefficient sequences are reconstructed into low-frequency power trend components, representing the overall trend of the power sequence.

[0091] Modulus maxima detection is performed on high-frequency power fluctuation components using a sliding window method, with a window width set (e.g., 5 to 11 sampling points). Within each window, if the absolute value of the center point is greater than the absolute values ​​of other points within the window, that point is marked as a modulus maxima point, and the corresponding time point is marked as a power abrupt change point. These abrupt change points reflect the rapid change characteristics of FM power.

[0092] When extracting power change rate features, for each marked power abrupt change point, its time position t_i is recorded, and the magnitude of the maximum modulus v_i at that point is taken as the power change amplitude at that abrupt change point. The power change rate before and after the abrupt change point is calculated, i.e., r_before=(P(t_i)-P(t_i-1)) / (t_i-t_i-1) and r_after=(P(t_i+1)-P(t_i)) / (t_i+1-t_i), where P(t) represents the power value at time t. Then, the jump variable Δr=r_after-r_before of the power change rate before and after the abrupt change point is calculated as an important indicator of the power change characteristics.

[0093] By combining the time location t_i of the power abrupt change point, the power change magnitude v_i, and the rate of change jump variable Δr, a triple (t_i, v_i, Δr) is formed, a complete power rate of change feature is constructed. These features can be used to identify different types of load change patterns and system disturbance events.

[0094] Zero-crossing point detection is performed on the low-frequency power trend component. The location of the zero-crossing point is determined by whether adjacent sampling points are one positive and one negative (or one negative and one positive). Simultaneously, extreme point detection is performed. The slope is calculated using the first-order difference method. When the slope changes from positive to negative or from negative to positive, the corresponding point is the extreme point. By comprehensively analyzing the zero-crossing points and extreme points, the power inflection point where power demand changes from increasing to decreasing or vice versa is identified.

[0095] The time interval between adjacent power inflection points is calculated as the duration of the monotonic power change. For example, if the times of two adjacent power inflection points are t_j and t_j+1, then the corresponding duration of the monotonic power change is Δt_j = t_j+1 - t_j. These durations reflect the temporal characteristics of frequency modulation power changes.

[0096] Frequency statistics are performed on the set of durations {Δt_j} with monotonically changing power, and frequency distribution histograms are established for different duration intervals. Appropriate probability distribution functions (such as log-normal distribution, Weibull distribution, etc.) are used to fit the frequency distributions to obtain the probability density function and cumulative distribution function of the duration, thus constituting the power duration characteristics.

[0097] In practical applications, for the frequency-modulated power sequence of a power plant, a four-level decomposition was performed using the db4 wavelet basis function, with an energy threshold set to 0.15. Calculations revealed that the energy proportions of the detail coefficients in the first and second levels were 0.18 and 0.16 respectively, exceeding the threshold. Therefore, these two levels of coefficients were reconstructed as high-frequency power fluctuation components; the remaining coefficients were reconstructed as low-frequency trend components. Modulus maxima detection identified 37 power abrupt change points in the 24-hour power sequence, with an average power change amplitude of 2.8 MW and an average rate of change jump of 0.65 MW / min. Zero-crossing and extreme point detection identified 82 power inflection points. The statistically obtained duration of monotonic power changes followed a log-normal distribution, with an average duration of 17.5 minutes.

[0098] By using the above time-frequency domain joint analysis method, the dynamic characteristics of the frequency regulation power sequence can be fully extracted, providing an important basis for optimizing the frequency regulation control strategy and analyzing the load characteristics of the power system.

[0099] In one optional implementation, and combining the reactor thermal inertia characteristics and control rod regulation delay characteristics in the current operating state parameters, the predicted power response boundary of the core generator unit for future time windows includes:

[0100] Based on the primary coolant temperature and reactor power level in the current operating status parameters, the response time constant of the primary coolant temperature to power change is calculated, and the response time constant of the steam generator pressure to power change is calculated based on the steam generator pressure and reactor power level. The two response time constants are used as the reactor thermal inertial characteristics.

[0101] Based on the control rod position and control rod movement speed limits in the current operating state parameters, the control rod position adjustment delay is calculated, and the control rod responsiveness adjustment delay is calculated based on the control rod responsiveness value curve. The control rod position adjustment delay and the control rod responsiveness adjustment delay are used as control rod adjustment delay features.

[0102] The reactor thermal inertial characteristics and the control rod regulation delay characteristics are coupled and calculated to determine the comprehensive response delay time required for the nuclear power unit to reach the target power level from receiving the power demand command.

[0103] Based on the reactor power level and adjustable power margin in the current operating status parameters, and combined with the comprehensive response delay time, the maximum power increase and maximum power decrease that the nuclear power unit can achieve at each moment in the future time window are calculated, and the power response boundary of the nuclear power unit in the future time window is obtained.

[0104] The reactor thermal inertial characteristics are obtained based on the current operating parameters and are achieved by calculating two response time constants: the response time constant of the primary coolant temperature to power change and the response time constant of the steam generator pressure to power change. In the specific implementation, the calculation process of the primary coolant temperature response time constant τ_coolant to power change is as follows: Obtain the power change ΔP = P2 - P1 corresponding to the change in reactor power from the initial power level P1 to the target power level P2, and record the starting time t_start of the power change; monitor the change of primary coolant temperature T_coolant in real time, and when the coolant temperature rises from the initial temperature T1 to the target temperature T2, record the time t_63.2% corresponding to the temperature reaching 63.2% of the change between T1 and T2, that is, the time when the coolant temperature reaches T1 + 0.632×(T2 - T1); calculate the time difference from the starting time t_start of the power change to the time t_63.2% when the temperature reaches 63.2% of the change, and this time difference is the primary coolant temperature response time constant τ_coolant = t_63.2% - t_start. For example, when the reactor power increases from 90% to 95%, the primary coolant temperature will lag. The time required from the start of the power change to the coolant temperature reaching 63.2% of the change is the required response time constant.

[0105] The calculation process for the steam generator pressure response time constant τ_steam to power change is as follows: Obtain the power change ΔP = P2 - P1 corresponding to the change in reactor power from the initial power level P1 to the target power level P2, and record the starting time t_start of the power change; monitor the change in steam generator pressure P_steam in real time, and when the steam generator pressure changes from the initial pressure P_s1 to the target pressure P_s2, record the time t_63.2% corresponding to the pressure reaching 63.2% of the change between P_s1 and P_s2, that is, the time when the steam generator pressure reaches P_s1 + 0.632×(P_s2 - P_s1); calculate the time difference between the starting time t_start of the power change and the time t_63.2% of the pressure reaching 63.2%, which is the steam generator pressure response time constant τ_steam = t_63.2% - t_start. These two time constants together constitute the reactor thermal inertia characteristics, which characterize the response speed of nuclear power unit thermal parameters to power changes.

[0106] The calculation of the control rod adjustment delay characteristics includes two parts: control rod position adjustment delay and control rod responsiveness adjustment delay. The calculation process of the control rod position adjustment delay T_position is as follows: obtain the current position H_current (expressed as a percentage of insertion depth) and the target position H_target; calculate the distance the control rod needs to move ΔH = |H_target - H_current|; obtain the preset control rod movement speed limit v_rod (usually expressed as a percentage per minute); divide the distance the control rod needs to move ΔH by the control rod movement speed limit v_rod to obtain the control rod position adjustment delay T_position = ΔH / v_rod. For example, if the current insertion depth of the control rod is 30%, the target position is 40%, and the control rod movement speed limit is 2% / minute, then the distance to move ΔH = 40% - 30% = 10%, and the time required to complete this adjustment is T_position = 10% / (2% / minute) = 5 minutes. This is the control rod position adjustment delay.

[0107] The control rod responsiveness adjustment delay is calculated based on the control rod responsiveness value curve. This curve describes the control rod's responsiveness adjustment capability at different insertion depths. Combined with the control rod position adjustment delay, the time required to complete a specific responsive adjustment can be calculated. These two delay parameters together constitute the control rod adjustment delay characteristic, characterizing the lag in the control system's execution of power adjustment commands.

[0108] After obtaining the above two characteristics, the reactor thermal inertia characteristics and control rod adjustment delay characteristics need to be coupled and calculated to determine the comprehensive response delay time required for the nuclear power unit to reach the target power level from receiving the power demand command. Specifically, the calculation process for the comprehensive response delay time T_total is as follows: First, identify the various stages in the power adjustment process, including the control rod position adjustment stage, the reactor power response stage, and the thermal parameter stabilization stage; obtain the control rod position adjustment delay T_position, the primary coolant temperature response time constant τ_coolant, and the steam generator pressure response time constant τ_steam; take the maximum value of the thermal response time constant as the thermal stabilization time T_thermal = max(τ_coolant, τ_steam); add the control rod position adjustment delay to the thermal stabilization time to obtain the comprehensive response delay time T_total = T_position + T_thermal. For example, for a 5% power increase command, the control rods need 3 minutes to complete the position adjustment, while the thermal parameters need an additional 2 minutes to reach a new equilibrium state; therefore, the comprehensive response delay time is 5 minutes.

[0109] Based on the current reactor power level, the theoretically adjustable range's upper and lower limits are determined. Considering the overall response delay time, the maximum possible power adjustment range is calculated for each time point within the future time window, starting from the current moment and reaching that time point. For example, if the current power is 90%, the theoretical upper limit is 100%, and a 10% increase requires an 8-minute overall response delay, then at the next 5-minute time point, the maximum power increase can only reach approximately 62.5% of the theoretical upper limit. By performing similar calculations for each time point within the future time window, an upper boundary curve and a lower boundary curve for the power response can be obtained. These two curves together constitute the power response boundary of the nuclear power unit within the future time window.

[0110] In practical applications, the predicted power response boundary can be directly used to support decision-making in power grid frequency regulation and peak shaving. For example, when the power grid dispatch center issues a power adjustment request, nuclear power units can quickly determine whether the adjustment requirements can be met and when the adjustment can be completed based on the predicted power response boundary, thereby providing a more accurate response commitment and improving the reliability and economy of nuclear power units participating in grid regulation.

[0111] In one optional implementation, the target frequency-modulated power sequence is decomposed into a power component borne by the nuclear power unit and a power component compensated by the supercapacitor. The supercapacitor-compensated power component includes power demand segments in the target frequency-modulated power sequence that exceed the power response boundary, including:

[0112] Traverse each moment within the future time window of the target frequency modulation power sequence, compare the power demand value at each moment with the power response boundary at the corresponding moment, calculate the difference between the power demand value and the maximum power increase and the maximum power decrease as the power increase gap and the power decrease gap respectively, and mark the moment with the power increase gap or the power decrease gap and the corresponding power gap value as the power demand segment.

[0113] For the power demand segment, the upward or downward power gap at each moment is taken as the power value that the supercapacitor needs to compensate at the corresponding moment and combined in time order to form the supercapacitor compensation power component.

[0114] For moments in the target frequency modulation power sequence that do not exceed the power response boundary, the power demand value at the corresponding moment is directly used as the power value undertaken by the nuclear power unit at the corresponding moment; for each moment in the power demand segment that exceeds the power response boundary, the maximum power increase or the maximum power decrease at the corresponding moment is used as the power value undertaken by the nuclear power unit at the corresponding moment; the power values ​​undertaken by the nuclear power unit at each moment are combined in chronological order to form the power component undertaken by the nuclear power unit.

[0115] Obtain the power response boundaries of the nuclear power unit, including the maximum power upscaling and maximum power downscaling. These parameters reflect the maximum adjustable capacity achievable by the nuclear power unit under safe and stable operating conditions. The maximum power upscaling can be determined comprehensively based on the current operating power of the nuclear power unit, the remaining reactivity of the core, and the operable range of the control rods. The maximum power downscaling is determined based on constraints such as core safety limits and primary loop temperature change rate limits.

[0116] Receive the target frequency-modulated power sequence, which represents the grid's frequency-modulated power demand on nuclear power units within a future time window. The target frequency-modulated power sequence can be represented as a series of time points and their corresponding expected power regulation values, such as the power regulation demand every 10 seconds over the next 15 minutes starting from the current moment.

[0117] The process iterates through each time window within the target frequency modulation power sequence, comparing the power demand value at each time point with the corresponding power response boundary. Specifically, it compares the power demand value with the maximum power increase margin; if the power demand value is greater than the maximum power increase margin, the difference is calculated as the power increase gap; conversely, it compares the power demand value with the maximum power decrease margin; if the power demand value is less than the maximum power decrease margin, the difference is calculated as the power decrease gap. The times when either a power increase gap or a power decrease gap exists, along with the corresponding power gap values, are marked as power demand segments.

[0118] For example, suppose that at time t1, the target frequency regulation power demand is +25MW, while the maximum power increase of nuclear power units is +20MW, then the power increase gap is 5MW; at time t2, the target frequency regulation power demand is -30MW, while the maximum power decrease of nuclear power units is -25MW, then the power decrease gap is -5MW. Thus, both times t1 and t2 are marked as power demand segments.

[0119] For the marked power demand segments, the upward or downward power gap at each moment is taken as the power value that the supercapacitor needs to compensate at the corresponding moment, and combined in chronological order to form the supercapacitor compensation power component. Continuing the example above, the supercapacitor needs to provide +5MW of compensation power at time t1 and -5MW of compensation power at time t2.

[0120] For moments in the target frequency regulation power sequence that do not exceed the power response boundary, the power demand value at that moment is directly used as the power value undertaken by the nuclear power unit at that moment. For example, if the power demand at moment t3 is +15MW, and this value does not exceed the power response boundary of the nuclear power unit, then the nuclear power unit undertakes +15MW of regulation power at moment t3.

[0121] For each moment within the power demand segment exceeding the power response boundary, the maximum power increase or decrease at that moment is taken as the power value undertaken by the nuclear power unit at that moment. Returning to the previous example, since the power demand of +25MW at moment t1 exceeds the maximum power increase of +20MW for the nuclear power unit, the power undertaken by the nuclear power unit at moment t1 is +20MW; similarly, the power undertaken by the nuclear power unit at moment t2 is -25MW.

[0122] By combining the power values ​​borne by the nuclear power units at each moment in chronological order, a power component borne by the nuclear power units is formed. In this way, the target frequency regulation power sequence is decomposed, enabling the nuclear power units to participate in grid frequency regulation to the maximum extent while ensuring safe operation. The supercapacitors compensate for the part that cannot be met, realizing a comprehensive response of the nuclear power-supercapacitor hybrid energy storage system to the grid frequency regulation demand.

[0123] Through the above decomposition method, nuclear power units can operate smoothly within their power response boundaries, while supercapacitors, with their fast response characteristics, supplement the short-term power demand that nuclear power units cannot meet, thereby improving the overall system's tracking accuracy and response speed to grid frequency regulation signals.

[0124] In one optional implementation, the energy margin constraint conditions for the supercapacitor are constructed based on the power amplitude and duration requirements of the supercapacitor's compensation power component, including:

[0125] Iterate through the supercapacitor compensation power component at each moment within the future time window, extract the power value that the supercapacitor needs to compensate at each moment as the instantaneous power demand and calculate the absolute value as the power amplitude, and count the time span of the continuous compensation power in the supercapacitor compensation power component as the duration demand.

[0126] Based on the power amplitude and the duration requirement, calculate the energy value required for the supercapacitor to accumulate discharge or charge at each moment in the future time window, and take the maximum value of the accumulated energy value in the future time window as the maximum energy requirement of the supercapacitor.

[0127] Based on the current state of charge and rated energy capacity of the supercapacitor, the current available energy reserve of the supercapacitor is calculated. When the maximum energy demand exceeds the current available energy reserve, the difference between the maximum energy demand and the current available energy reserve is calculated as the energy gap.

[0128] Based on the energy gap and the instantaneous power demand of the supercapacitor's compensation power component at each moment within the future time window, a constraint condition is constructed that the state of charge of the supercapacitor at each moment within the future time window must be within the allowable range of the rated energy capacity, which serves as the energy margin constraint condition for the supercapacitor.

[0129] In practical applications, supercapacitors typically work in conjunction with other energy storage devices to compensate for power fluctuations in the power grid or electrical equipment based on their different power and energy characteristics. Before constructing the energy margin constraints, the power component that the supercapacitor needs to compensate for has been obtained through power coordination optimization.

[0130] For the acquired supercapacitor compensation power components, the system iterates through each moment within the future time window, extracting the power value that the supercapacitor needs to compensate at each moment as the instantaneous power demand. For example, within a 10-minute future time window, with a sampling interval of 1 second, there are a total of 600 sampling points. The absolute value of the power value at each sampling point is calculated to obtain the power amplitude. Simultaneously, the time span of continuous compensation power is statistically analyzed as the duration demand. For instance, if the supercapacitor continuously provides discharge power from the 30th second to the 45th second, then the duration demand for this segment is 15 seconds.

[0131] Based on the power amplitude and duration requirements, the energy required for cumulative discharge or charging of the supercapacitor at each moment within a future time window is calculated. Specifically, starting from the beginning of the time window, the power value at each moment is multiplied by the time interval. For example, if the power value at a certain moment is -50 kW (a negative value indicates discharge) and the time interval is 1 second, then the energy change at that moment is -50 kJ. Through cumulative calculation, the cumulative energy change value relative to the initial state at each moment within the future time window is obtained. From these cumulative energy change values, the largest positive value (representing the maximum charging demand) and the smallest negative value (representing the maximum discharging demand) are identified; the larger of their absolute values ​​is the maximum energy requirement of the supercapacitor.

[0132] Based on the current state of charge and rated energy capacity of the supercapacitor, calculate its current available energy reserve. Assuming the rated energy capacity of the supercapacitor is 10 kWh and the current state of charge is 60%, considering the safe operating range of 20% to 90%, the current available discharge energy reserve is (60% - 20%) × 10 kWh = 4 kWh, and the available charging energy reserve is (90% - 60%) × 10 kWh = 3 kWh.

[0133] The maximum energy demand is compared with the current available energy reserves. When the maximum energy demand exceeds the current available energy reserves, the difference between the two is calculated as the energy gap. For example, if the maximum discharge demand is 5 kWh, but the current available discharge energy reserves are only 4 kWh, then the energy gap is 1 kWh.

[0134] Based on the energy gap and the instantaneous power demand of the supercapacitor's compensation power component at each moment within the future time window, constraints on the supercapacitor's state of charge (SOC) at each moment within the future time window are constructed. Specifically, the initial SOC is set to the current value, and then the SOC at each future moment is predicted based on the power demand at each moment. For any moment t, the SOC should satisfy: SOC_min ≤ SOC(t) ≤ SOC_max, where SOC_min and SOC_max are the minimum and maximum allowable SOCs of the supercapacitor, respectively.

[0135] When the predicted state of charge (SOC) exceeds the allowable range, the compensation power component of the supercapacitor needs to be adjusted. The adjustment method can be to proportionally reduce the power demand exceeding the energy margin, or to reallocate the power compensation task over time. The first method is to proportionally reduce the power demand: calculate the ratio of the energy gap to the maximum energy demand to obtain the power reduction coefficient k = 1 - (energy gap / maximum energy demand); iterate through the future time windows at each moment that causes the SOC to exceed the allowable range, multiplying the supercapacitor compensation power value at these moments by the reduction coefficient k to proportionally reduce it; recalculate the adjusted SOC at each moment and verify whether the constraint condition SOC_min ≤ SOC(t) ≤ SOC_max is satisfied. For example, if it is predicted that the state of charge of the supercapacitor will drop to 15% (below the safe limit of 20%) at the 50th second, the energy gap is 1 kWh, and the maximum energy demand is 5 kWh, then the power reduction factor k = 1 - 1 / 5 = 0.8. All discharge power values ​​from the 1st to the 50th second are multiplied by 0.8 to reduce the state of charge at the 50th second so that it is exactly not lower than 20%.

[0136] The second adjustment method involves reallocating power compensation tasks over time: identifying critical time periods that cause the state of charge (SOC) to exceed the allowable range, such as continuous high-power discharge between the 30th and 50th seconds leading to an excessively low SOC; calculating the total energy to be reduced during this time period, and transferring this portion of the power compensation task to other energy storage devices or delaying its execution until the supercapacitor's SOC recovers; in practice, the power demand exceeding the energy margin during the critical time period can be allocated to energy storage devices such as lithium batteries, or a charging period can be inserted after this time period to allow the supercapacitor's SOC to recover before continuing the subsequent discharge task. For example, if it is predicted that the SOC will drop to 15% at the 50th second, 20% of the discharge power demand between the 40th and 50th seconds can be transferred to the battery, ensuring that the supercapacitor's SOC remains at 22% at the 50th second, meeting the safety lower limit requirement.

[0137] The energy margin constraint conditions constructed by the above method ensure that the state of charge of the supercapacitor is always kept within a safe operating range when performing power compensation tasks, avoiding damage and performance degradation caused by overcharging and over-discharging, extending the service life of the equipment, and improving the reliability and economy of the energy management system.

[0138] In one optional implementation, adjusting the power ramp rate of the power component borne by the nuclear power unit, and using the adjusted supercapacitor to compensate for the power component to perform real-time compensation for power fluctuations in the adjusted power component borne by the nuclear power unit includes:

[0139] Using the constraints of nuclear power unit power ramp-up rate and supercapacitor energy margin as boundary conditions, the power value of the power component undertaken by the nuclear power unit at each time within a future time window is optimized and redistributed. Within the boundary conditions, with the goal of minimizing the fluctuation of nuclear power unit power ramp-up rate, the optimal power sharing ratio between the nuclear power unit and the supercapacitor at each time is calculated.

[0140] The power sequence undertaken by the nuclear power units after the optimized redistribution is taken as the adjusted power component undertaken by the nuclear power units, and the power sequence newly undertaken by the supercapacitors after the optimized redistribution is superimposed on the supercapacitor compensation power component to form the adjusted supercapacitor compensation power component.

[0141] Based on the deviation sequence between the adjusted nuclear power unit's power component and the actual power output value of the nuclear power unit, the frequency domain characteristics and time domain evolution law of the deviation sequence are extracted. The amplitude and phase of the nuclear power unit's power fluctuation in the future period are predicted using the frequency domain characteristics and time domain evolution law, and the corresponding power deviation prediction value is calculated. The power deviation prediction value is superimposed on the adjusted supercapacitor compensation power component to generate a supercapacitor feedforward compensation command.

[0142] Using the power ramp-up rate constraint of the nuclear power unit and the energy margin constraint of the supercapacitor as boundary conditions, the power value of the power component undertaken by the nuclear power unit at each time point within a future time window is optimized and redistributed. Specifically, the future time window is set as T. For each discrete time point t∈[1,T], the power ramp-up rate constraint of the nuclear power unit is expressed as the power change rate of the nuclear power unit at adjacent time points cannot exceed its maximum allowable change rate. Assuming that the power value of the nuclear power unit at time t is Pn(t), the power ramp-up rate constraint can be expressed as |Pn(t)-Pn(t-1)|≤ΔPmax, where ΔPmax is the maximum allowable power change rate of the nuclear power unit.

[0143] Meanwhile, the supercapacitor energy margin constraint means that the energy state of the supercapacitor should be maintained within a safe range throughout the entire time window. Let the power output of the supercapacitor at time t be Psc(t), and its initial energy state be Esc(0). Then, at any time t, the energy state of the supercapacitor is Esc(t) = Esc(0) - ∑Psc(i)·Δt, where i ranges from 1 to t, and Δt is the time step. To ensure the safe operation of the system, it is necessary to satisfy Esc,min ≤ Esc(t) ≤ Esc,max, where Esc,min and Esc,max are the minimum and maximum allowable energy states of the supercapacitor, respectively.

[0144] Under the aforementioned boundary conditions, with the optimization objective of minimizing the fluctuation of the nuclear power unit's power ramp-up rate, the optimal power sharing ratio between the nuclear power unit and the supercapacitor at each time point is calculated. The optimization objective function can be expressed as minimizing ∑(Pn(t)-Pn(t-1)). 2 , where t ranges from 2 to T. By solving this optimization problem, we obtain the optimized power value Pn_opt(t) of the nuclear power unit at each time and the power value Psc_add(t) = Preq(t) - Pn_opt(t) that the supercapacitor needs to replenish at each time, where Preq(t) is the total power demand of the system at time t.

[0145] The power sequence {Pn_opt(t)} undertaken by the nuclear power units after the optimized redistribution is taken as the adjusted power component undertaken by the nuclear power units. The power sequence {Psc_add(t)} newly undertaken by the supercapacitors after the optimized redistribution is superimposed on the original supercapacitor compensation power component {Psc_orig(t)} to form the adjusted supercapacitor compensation power component {Psc_adj(t)=Psc_orig(t)+Psc_add(t)}.

[0146] Next, the deviation sequence between the adjusted power component of the nuclear power unit and the actual power output value of the nuclear power unit is analyzed. Let the actual power output of the nuclear power unit at time t be Pn_actual(t), then the deviation sequence is {Δ(t)=Pn_opt(t)-Pn_actual(t)}. Frequency domain analysis is performed on this deviation sequence, using Fast Fourier Transform to extract its frequency domain features, including the main frequency components and their amplitude and phase information. Simultaneously, time-series analysis methods, such as the autoregressive integral moving average model, are used to extract the time-domain evolution of the deviation sequence, including characteristics such as trend, periodicity, and autocorrelation.

[0147] Based on the aforementioned frequency domain characteristics and time domain evolution patterns, a hybrid prediction method is employed to predict the amplitude and phase of power fluctuations in the core generator units during future periods. Specifically, assuming a prediction time window of τ, for a future time t+i (i∈[1,τ]), the predicted power deviation is Δpred(t+i). This predicted value comprehensively considers the frequency domain decomposition results and time domain evolution trends of the historical deviation sequence, and can accurately reflect the fluctuation characteristics of the core generator unit's power output during future periods.

[0148] The predicted power deviation sequence {Δpred(t+i)} is superimposed onto the adjusted supercapacitor compensation power component to generate the supercapacitor feedforward compensation command {Psc_ff(t+i)=Psc_adj(t+i)+Δpred(t+i)}. Through this feedforward compensation mechanism, the supercapacitor can respond in advance to power fluctuations that may occur in the nuclear power unit, effectively reducing the fluctuation amplitude of the system power output and improving the dynamic performance and stability of the system.

[0149] In practical applications, the parameter settings in the above methods can be flexibly adjusted according to the type of nuclear power unit, the capacity of the supercapacitor, and the frequency regulation requirements of the power grid. For example, the time window size and the weight of the objective function can be adjusted. For power grid areas with high frequency regulation requirements, the power ramp-up rate constraint of the nuclear power unit can be appropriately increased, and a larger capacity supercapacitor can be configured to improve the frequency regulation capability of the system. For areas with lower frequency regulation requirements but higher stability requirements, the power ramp-up rate constraint of the nuclear power unit can be appropriately reduced, and the capacity configuration of the supercapacitor can be reduced to lower the system cost.

[0150] Using the above method, nuclear power units and supercapacitors can work collaboratively, meeting both the frequency regulation requirements of the power grid and ensuring the safe and stable operation of the nuclear power units, achieving a technological breakthrough in the participation of nuclear power units in power grid frequency regulation. This method is not only applicable to collaborative frequency regulation systems of nuclear power units and supercapacitors, but can also be extended to collaborative control schemes of other types of generator units and energy storage devices.

[0151] This invention relates to a nuclear power primary frequency regulation power smoothing control system based on supercapacitors, the system comprising:

[0152] The first unit is used to calculate the target frequency regulation power demand based on the current operating status parameters of the nuclear power unit and the deviation of the grid frequency, and to obtain the target frequency regulation power sequence.

[0153] The second unit is used to perform joint time-frequency domain analysis on the target frequency-modulated power sequence, extract the power change rate characteristics and power duration characteristics of the target frequency-modulated power sequence, and combine the reactor thermal inertia characteristics and control rod regulation delay characteristics in the current operating state parameters to predict the power response boundary of the core generator unit in the future time window.

[0154] The third unit is used to decompose the target frequency modulation power sequence into a nuclear power unit-borne power component and a supercapacitor-compensated power component, wherein the supercapacitor-compensated power component includes the power demand segment in the target frequency modulation power sequence that exceeds the power response boundary.

[0155] The fourth unit is used to construct the energy margin constraint condition of the supercapacitor based on the power amplitude and duration requirement of the supercapacitor compensation power component, and transfer the power requirement of the supercapacitor compensation power component that exceeds the energy margin constraint condition to the nuclear power unit to bear the power component.

[0156] The fifth unit is used to adjust the power ramp rate of the power component undertaken by the nuclear power unit, and to use the adjusted supercapacitor to compensate for the power fluctuation of the adjusted power component undertaken by the nuclear power unit in real time, thereby smoothing the power output curve of the nuclear power unit.

[0157] A third aspect of the present invention provides an electronic device, comprising:

[0158] processor;

[0159] Memory used to store processor-executable instructions;

[0160] The processor is configured to invoke instructions stored in the memory to execute the aforementioned method.

[0161] A fourth aspect of the present invention provides a computer-readable storage medium having stored thereon computer program instructions that, when executed by a processor, implement the aforementioned method.

[0162] This invention can be a method, apparatus, system, and / or computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for performing various aspects of the invention.

[0163] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for smoothing primary frequency regulation power control of nuclear power plants based on supercapacitors, characterized in that, include: The target frequency regulation power demand is calculated based on the current operating status parameters of the nuclear power unit and the frequency deviation of the power grid, and the target frequency regulation power sequence is obtained. A joint time-frequency domain analysis is performed on the target frequency-modulated power sequence to extract the power change rate characteristics and power duration characteristics of the target frequency-modulated power sequence. Combined with the reactor thermal inertia characteristics and control rod regulation delay characteristics in the current operating state parameters, the power response boundary of the core generator unit in the future time window is predicted. The target frequency modulation power sequence is decomposed into a power component borne by the nuclear power unit and a power component compensated by the supercapacitor. The power component compensated by the supercapacitor includes the power demand segment in the target frequency modulation power sequence that exceeds the power response boundary. Based on the power amplitude and duration requirements of the supercapacitor compensation power component, an energy margin constraint condition for the supercapacitor is constructed, and the power demand of the supercapacitor compensation power component exceeding the energy margin constraint condition is transferred to the nuclear power unit to bear the power component. The power ramp rate of the power component undertaken by the nuclear power unit is adjusted, and the power fluctuation of the adjusted nuclear power unit is compensated in real time by using the adjusted supercapacitor to smooth the power output curve of the nuclear power unit.

2. The method according to claim 1, characterized in that, Based on the current operating parameters of the nuclear power unit and the frequency deviation from the power grid, the target frequency regulation power demand is calculated, resulting in the target frequency regulation power sequence, including: Collect reactor power level, primary coolant temperature, steam generator pressure, control rod position, and grid frequency deviation signals of the nuclear power unit; Based on the grid frequency deviation signal and the preset primary frequency regulation control strategy, the initial frequency regulation power requirement that the nuclear power unit should output is calculated. The current power operating margin is calculated based on the reactor power level and the rated power of the nuclear power unit; the thermal margin is calculated based on the primary coolant temperature and the safe operating temperature limit; the control margin is calculated based on the control rod position and the control rod stroke limit; and the pressure margin is calculated based on the steam generator pressure and the pressure safety boundary. The minimum value among the power operating margin, the thermal margin, the control margin, and the pressure margin is determined as the current adjustable power margin of the nuclear power unit. When the initial frequency regulation power demand exceeds the adjustable power margin, the initial frequency regulation power demand is reduced to the value of the adjustable power margin to generate a corrected frequency regulation power demand that meets the safe operation boundary of the nuclear power unit. The modified frequency modulation power demand is discretized along the time axis according to a preset time sampling interval. The power demand value corresponding to each sampling moment is calculated to form the target frequency modulation power sequence containing power demand values ​​at multiple moments.

3. The method according to claim 1, characterized in that, Performing joint time-frequency domain analysis on the target frequency-modulated power sequence to extract the power change rate characteristics and power duration characteristics of the target frequency-modulated power sequence includes: The target frequency-modulated power sequence is decomposed by wavelet to obtain multiple wavelet coefficient sequences of different frequency bands. The energy proportion of the wavelet coefficient sequence of each frequency band is calculated. The wavelet coefficient sequence corresponding to the frequency band with the energy proportion greater than the preset energy threshold is reconstructed into a high-frequency power fluctuation component. The remaining wavelet coefficient sequences are reconstructed into a low-frequency power trend component. The high-frequency power fluctuation component is subjected to modulus maxima detection, and the time corresponding to the obtained modulus maxima is marked as a power abrupt change point; the amplitude of the modulus maxima is used as the power change amplitude at the power abrupt change point; the difference between the power change rate before and after the power abrupt change point is calculated as the jump variable of the power change rate between the two time points; the time position of the power abrupt change point, the power change amplitude, and the jump variable are combined to form the power change rate feature; Zero-crossing point detection and extreme point detection are performed on the low-frequency power trend component to identify the power inflection points in the target frequency modulation power sequence where the power demand changes from rising to falling or from falling to rising. The time interval between adjacent power inflection points is calculated as the duration of the monotonic power change. Frequency statistics and probability distribution fitting are performed on the duration of the monotonic power change to obtain the power duration feature.

4. The method according to claim 2, characterized in that, Based on the reactor thermal inertia characteristics and control rod regulation delay characteristics in the current operating state parameters, the predicted power response boundaries of the core generator unit in the future time window include: Based on the primary coolant temperature and reactor power level in the current operating status parameters, the response time constant of the primary coolant temperature to power change is calculated, and the response time constant of the steam generator pressure to power change is calculated based on the steam generator pressure and reactor power level. The two response time constants are used as the reactor thermal inertial characteristics. Based on the control rod position and control rod movement speed limits in the current operating state parameters, the control rod position adjustment delay is calculated, and the control rod responsiveness adjustment delay is calculated based on the control rod responsiveness value curve. The control rod position adjustment delay and the control rod responsiveness adjustment delay are used as control rod adjustment delay features. The reactor thermal inertia characteristics are coupled with the control rod adjustment delay characteristics to determine the comprehensive response delay time required for the nuclear power unit to reach the target power level from receiving the power demand command. Based on the reactor power level and adjustable power margin in the current operating status parameters, and combined with the comprehensive response delay time, the maximum power increase and maximum power decrease that the nuclear power unit can achieve at each moment in the future time window are calculated, and the power response boundary of the nuclear power unit in the future time window is obtained.

5. The method according to claim 4, characterized in that, The target frequency-modulated power sequence is decomposed into a power component supplied by nuclear power units and a power component compensated by supercapacitors. The supercapacitor-compensated power component includes power demand segments in the target frequency-modulated power sequence that exceed the power response boundary, including: Traverse each moment within the future time window of the target frequency modulation power sequence, compare the power demand value at each moment with the power response boundary at the corresponding moment, calculate the difference between the power demand value and the maximum power increase and the maximum power decrease as the power increase gap and the power decrease gap respectively, and mark the moment with the power increase gap or the power decrease gap and the corresponding power gap value as the power demand segment. For the power demand segment, the upward or downward power gap at each moment is taken as the power value that the supercapacitor needs to compensate at the corresponding moment and combined in time order to form the supercapacitor compensation power component. For moments in the target frequency modulation power sequence that do not exceed the power response boundary, the power demand value at the corresponding moment is directly used as the power value undertaken by the nuclear power unit at the corresponding moment; for each moment in the power demand segment that exceeds the power response boundary, the maximum power increase or the maximum power decrease at the corresponding moment is used as the power value undertaken by the nuclear power unit at the corresponding moment; the power values ​​undertaken by the nuclear power unit at each moment are combined in chronological order to form the power component undertaken by the nuclear power unit.

6. The method according to claim 1, characterized in that, Based on the power amplitude and duration requirements of the supercapacitor's compensation power component, the energy margin constraints for the supercapacitor are constructed as follows: Iterate through the supercapacitor compensation power component at each moment within the future time window, extract the power value that the supercapacitor needs to compensate at each moment as the instantaneous power demand and calculate the absolute value as the power amplitude, and count the time span of the continuous compensation power in the supercapacitor compensation power component as the duration demand. Based on the power amplitude and the duration requirement, calculate the energy value required for the supercapacitor to accumulate discharge or charge at each moment in the future time window, and take the maximum value of the accumulated energy value in the future time window as the maximum energy requirement of the supercapacitor. Based on the current state of charge and rated energy capacity of the supercapacitor, the current available energy reserve of the supercapacitor is calculated. When the maximum energy demand exceeds the current available energy reserve, the difference between the maximum energy demand and the current available energy reserve is calculated as the energy gap. Based on the energy gap and the instantaneous power demand of the supercapacitor's compensation power component at each moment within the future time window, a constraint condition is constructed that the state of charge of the supercapacitor at each moment within the future time window must be within the allowable range of the rated energy capacity, which serves as the energy margin constraint condition for the supercapacitor.

7. The method according to claim 1, characterized in that, Adjusting the power ramp rate of the power component undertaken by the nuclear power unit, and using the adjusted supercapacitor to compensate for the power component to perform real-time compensation for power fluctuations in the adjusted power component undertaken by the nuclear power unit, includes: Using the constraints of nuclear power unit power ramp-up rate and supercapacitor energy margin as boundary conditions, the power value of the power component undertaken by the nuclear power unit at each time within a future time window is optimized and redistributed. Within the boundary conditions, with the goal of minimizing the fluctuation of nuclear power unit power ramp-up rate, the optimal power sharing ratio between the nuclear power unit and the supercapacitor at each time is calculated. The power sequence undertaken by the nuclear power units after the optimized redistribution is taken as the adjusted power component undertaken by the nuclear power units, and the power sequence newly undertaken by the supercapacitors after the optimized redistribution is superimposed on the supercapacitor compensation power component to form the adjusted supercapacitor compensation power component. Based on the deviation sequence between the adjusted nuclear power unit's power component and the actual power output value of the nuclear power unit, the frequency domain characteristics and time domain evolution law of the deviation sequence are extracted. The amplitude and phase of the nuclear power unit's power fluctuation in the future period are predicted using the frequency domain characteristics and time domain evolution law, and the corresponding power deviation prediction value is calculated. The power deviation prediction value is superimposed on the adjusted supercapacitor compensation power component to generate a supercapacitor feedforward compensation command.

8. A nuclear power primary frequency regulation power smoothing control system based on supercapacitors, used to implement the method as described in any one of claims 1-7, characterized in that, include: The first unit is used to calculate the target frequency regulation power demand based on the current operating status parameters of the nuclear power unit and the deviation of the grid frequency, and to obtain the target frequency regulation power sequence. The second unit is used to perform joint time-frequency domain analysis on the target frequency-modulated power sequence, extract the power change rate characteristics and power duration characteristics of the target frequency-modulated power sequence, and combine the reactor thermal inertia characteristics and control rod regulation delay characteristics in the current operating state parameters to predict the power response boundary of the core generator unit in the future time window. The third unit is used to decompose the target frequency modulation power sequence into a nuclear power unit-borne power component and a supercapacitor-compensated power component, wherein the supercapacitor-compensated power component includes the power demand segment in the target frequency modulation power sequence that exceeds the power response boundary. The fourth unit is used to construct the energy margin constraint condition of the supercapacitor based on the power amplitude and duration requirement of the supercapacitor compensation power component, and transfer the power requirement of the supercapacitor compensation power component that exceeds the energy margin constraint condition to the nuclear power unit to bear the power component. The fifth unit is used to adjust the power ramp rate of the power component undertaken by the nuclear power unit, and to use the adjusted supercapacitor to compensate for the power fluctuation of the adjusted power component undertaken by the nuclear power unit in real time, thereby smoothing the power output curve of the nuclear power unit.

9. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to invoke instructions stored in the memory to execute the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having computer program instructions stored thereon, characterized in that, When the computer program instructions are executed by the processor, they implement the method described in any one of claims 1 to 7.

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