A method and system for primary frequency modulation control of a nuclear power plant

Abstract

This invention discloses a primary frequency regulation control method and system for nuclear power plants, used to calculate the total steam demand value of the turbine generator set in a nuclear power plant. The method includes: S1, performing a first calculation on the target speed of the generator to obtain a first steam demand value; S2, obtaining the actual speed of the generator and performing a second calculation on the actual speed and the target speed to obtain a steam adjustment value; S3, performing a limit calculation on the actual load of the generator and the steam adjustment value based on the generator's operating state and / or reactor power to obtain a second steam demand value; S4, calculating the total steam demand value based on the first steam demand value and the second steam demand value, and returning to S2. This invention can avoid the situation where the primary frequency regulation continues to operate in the forward direction when the generator or reactor is at full power load, leading to reactor over-power, and avoid the primary frequency regulation being put into operation immediately after the generator is connected to the grid, thereby improving the stability of the turbine generator set and reactor control system.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant turbine generator control technology, and in particular to a primary frequency regulation control method and system for nuclear power plants. Background Technology

[0002] For nuclear power plants, power coordination control between the reactor and the generator (steam turbine generator) is extremely important, as it involves the conversion of nuclear energy into electrical energy and the energy balance between them. During load operation, a control mode is typically adopted where the reactor power follows the turbine power variation; that is, the reactor adjusts its power based on a certain state parameter of the generator. The turbine control and power control rod control systems coordinate with each other to ensure energy balance between the primary and secondary loops, maintaining the safe, economical, and stable operation of the nuclear power plant.

[0003] As the proportion of high-power generating units in the power grid continues to increase, the peak-to-valley load difference caused by changes in power grid consumption patterns is widening. Activating primary frequency regulation for large-capacity generating units will effectively ensure the safe operation of the power grid. Currently, most nuclear power plants are required to have primary frequency regulation functionality. However, current nuclear power plant primary frequency regulation designs have the following shortcomings: improper frequency regulation amplitude settings may lead to excessively high load ramp-up and ramp-down rates, failing to meet the technical specifications for nuclear power unit operation; primary frequency regulation may still operate positively even at full power in the nuclear island, potentially causing reactor over-power; and the primary frequency regulation dead zone is automatically activated immediately after grid connection, which can affect the stability of unit control. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and system for primary frequency regulation control of nuclear power plants, addressing at least one deficiency in the existing technology.

[0005] The technical solution adopted by this invention to solve its technical problem is: to construct a primary frequency regulation control method for a nuclear power plant, used to calculate the total steam demand of the turbine generator unit of the nuclear power plant, including the following steps:

[0006] S1. Perform the first calculation on the target speed of the generator to obtain the first steam demand value;

[0007] S2. Obtain the actual speed of the generator, and perform a second calculation based on the actual speed and the target speed to obtain the steam adjustment value;

[0008] S3. Based on the operating status of the generator and / or the reactor power, perform limit calculations on the actual load of the generator and the steam adjustment value to obtain a second steam demand value.

[0009] S4. Calculate the total steam demand value based on the first steam demand value and the second steam demand value, and return to S2.

[0010] Preferably, in step S3, the limit value calculation process includes:

[0011] S31. Determine whether it is necessary to limit the steam adjustment value based on the operating status of the generator and / or the reactor power. If yes, proceed to step S32; otherwise, proceed to step S35.

[0012] S32. Compare the actual load according to the preset power range to obtain comparison data;

[0013] S33. Perform limit processing on the comparison data to obtain the limit range;

[0014] S34. Set the second steam demand value according to the limit range and the steam adjustment value, and execute S4.

[0015] S35. Set the second steam demand value to the steam adjustment value and execute S4.

[0016] Preferably, in step S31, determining whether a limit needs to be imposed on the steam adjustment value based on the generator's operating state and / or reactor power includes:

[0017] When the generator is connected to the grid, and there are no grid disturbances or load shedding phenomena, and the reactor is at full power load, it is determined that the steam adjustment value needs to be limited; when the generator is not connected to the grid, or there are grid disturbances or load shedding phenomena, it is determined that the steam adjustment value does not need to be limited.

[0018] Preferably, in S32, the comparison process includes:

[0019] The first comparison value is obtained by subtracting the actual load from the upper limit of the preset power range; the second comparison value is obtained by subtracting the actual load from the lower limit of the preset power range; the first comparison value and the second comparison value constitute the comparison data.

[0020] Preferably, in S33, the limit processing includes:

[0021] The larger of the first preset comparison value and the first comparison value is taken as the first larger value, and the smaller of the preset upper limit value and the first larger value is set as the upper limit value of the limit range;

[0022] The smaller of the second preset comparison value and the second comparison value is taken as the first smaller value, and the larger of the preset lower limit value and the first smaller value is set as the lower limit value of the limit range.

[0023] Preferably, S34 includes:

[0024] If the steam adjustment value is within the limit range, then the second steam demand value is set to the steam adjustment value; if the steam adjustment value is less than the lower limit of the limit range, then the second steam demand value is set to the lower limit of the limit range; if the steam adjustment value is greater than the upper limit of the limit range, then the second steam demand value is set to the upper limit of the limit range, and step S4 is executed.

[0025] Preferably, in S2, the second arithmetic process includes:

[0026] Calculate the difference between the target speed and the actual speed, and determine whether to perform dead zone determination processing based on the commissioning status of the primary frequency regulation and the working status of the generator. If so, set the speed feedback value to the value obtained after the dead zone determination processing; otherwise, set the speed feedback value to the difference.

[0027] The steam adjustment value is obtained by performing adjustment value calculation on the speed feedback value.

[0028] This invention also constructs a primary frequency regulation control system for a nuclear power plant, used to calculate the total steam demand of the nuclear power plant's turbine generator unit, including:

[0029] The first arithmetic unit is used to perform a first arithmetic processing on the target speed of the generator to generate a first steam demand value;

[0030] The second calculation unit is used to obtain the actual speed of the generator and perform a second calculation based on the actual speed and the target speed to generate a steam adjustment value;

[0031] The limit calculation unit is used to perform limit calculation processing on the actual load of the generator and the steam adjustment value according to the operating status of the generator and / or the reactor power, and generate a second steam demand value.

[0032] The total steam demand calculation unit is used to calculate the total steam demand value based on the first steam demand value and the second steam demand value.

[0033] Preferably, the limit value calculation unit includes a first state judgment unit, a first switching unit, and a limit value unit;

[0034] The first state determination unit is used to determine whether it is necessary to limit the steam adjustment value based on the operating state of the generator and / or the reactor power, and transmit the determination result to the first switching unit.

[0035] The first switching unit sets the second steam demand value to the limit value output by the limit unit or the steam adjustment value based on the judgment result;

[0036] The limit unit includes a comparison processing unit, a limit range setting unit, and an output unit.

[0037] The comparison processing unit is used to compare the actual load according to a preset power range and generate comparison data.

[0038] The limit range setting unit is used to perform limit processing on the comparison data and generate a limit range.

[0039] The output unit is used to output the limit value based on the limit range and the steam adjustment value.

[0040] Preferably, the first state judgment unit includes a first AND gate, a first OR gate, and a first NOT gate; the first input terminal of the first AND gate is used to receive the generator grid connection status signal, the input terminal of the first OR gate is used to receive the generator grid disturbance feedback signal, load shedding feedback signal, and reactor power status signal, the output terminal of the first OR gate is connected to the input terminal of the first NOT gate, the output terminal of the first NOT gate is connected to the second input terminal of the first AND gate, and the output terminal of the first AND gate is connected to the limit calculation unit to send the judgment result to the first switching unit.

[0041] Preferably, the comparison processing unit includes a first subtractor and a second subtractor;

[0042] The first input terminal of the first subtractor is used to receive the upper limit value of the preset power range, the second input terminal of the first subtractor is used to receive the actual load, and the output terminal of the first subtractor is connected to the limit range setting unit.

[0043] The first input terminal of the second subtractor is used to receive the lower limit value of the preset power range, the second input terminal of the second subtractor is used to receive the actual load, and the output terminal of the second subtractor is connected to the limit range setting unit.

[0044] Preferably, the limit range setting unit includes a first larger unit, a first smaller unit, a second smaller unit, and a second larger unit;

[0045] The first input terminal of the first large-value unit is connected to the output terminal of the first subtractor, the second input terminal of the first large-value unit is used to receive a first preset comparison value, the output terminal of the first large-value unit is connected to the second input terminal of the first small-value unit, the first input terminal of the first small-value unit is used to receive a preset upper limit value, and the output terminal of the first small-value unit is connected to the output unit.

[0046] The first input terminal of the second smaller unit is connected to the output terminal of the second subtractor, the second input terminal of the second smaller unit is used to receive a second preset comparison value, the output terminal of the second smaller unit is connected to the first input terminal of the second larger unit, the second input terminal of the second larger unit is used to receive a preset lower limit value, and the output terminal of the second larger unit is connected to the output unit.

[0047] Preferably, the output unit includes a limiting unit;

[0048] The upper limit setting terminal of the limiting unit is connected to the output terminal of the first smaller value unit, the lower limit setting terminal of the limiting unit is connected to the output terminal of the second larger value unit, the input terminal of the limiting unit is connected to the second arithmetic unit, and the output terminal of the limiting unit is connected to the first switching unit.

[0049] This invention provides at least the following beneficial effects: It offers a primary frequency regulation control method for nuclear power plants. This method involves performing a first calculation on the target speed of the generator to obtain a first steam demand value; simultaneously acquiring the actual speed of the generator and performing a second calculation based on the actual and target speeds to obtain a steam adjustment value; then, performing a limit calculation on the actual load of the generator and the steam adjustment value based on the generator's operating state and / or reactor power to obtain a second steam demand value; and finally, calculating the total steam demand value based on the first and second steam demand values. Implementing this invention can prevent the primary frequency regulation from continuing to operate forward when the generator or reactor is at full power load, thus avoiding reactor over-power situations. It also avoids excessive load fluctuations during primary frequency regulation that could violate unit operation specifications, and prevents overly frequent frequency regulation operations. Furthermore, it avoids immediate operation of primary frequency regulation after the generator is connected to the grid, thereby improving the stability of the turbine generator set and reactor control system. Attached Figure Description

[0050] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0051] Figure 1 This is a flowchart of a primary frequency regulation control method for a nuclear power plant provided by the present invention;

[0052] Figure 2 This is a flowchart of step S3 in a primary frequency regulation control method for a nuclear power plant provided by the present invention;

[0053] Figure 3 This is a schematic diagram of an embodiment of a primary frequency regulation control system for a nuclear power plant provided by the present invention;

[0054] Figure 4 This is a schematic diagram of the structure of a second embodiment of a primary frequency regulation control system for a nuclear power plant provided by the present invention. Detailed Implementation

[0055] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0056] refer to Figure 1 This invention discloses a primary frequency regulation control method for a nuclear power plant, used to calculate the total steam demand of the turbine generator unit in the nuclear power plant, including steps S1, S2, S3, and S4:

[0057] Step S1 includes: performing a first calculation on the target speed of the generator to obtain a first steam demand value. Specifically, the first calculation includes: substituting the target speed into a set function to obtain the first steam demand value. In some embodiments, the first steam demand value is generally fixed at 4%. Furthermore, in a steam turbine generator set, ideally, the steam demand value is linearly related to the generator power, and the magnitude of the generator power and the steam demand value can be characterized as a percentage of their respective ratings.

[0058] Step S2 includes: obtaining the actual speed of the generator, and performing a second calculation based on the actual speed and the target speed to obtain the steam adjustment value.

[0059] In some embodiments, the second calculation process in step S2 includes: calculating the difference between the target speed and the actual speed, and determining whether to perform dead zone determination processing based on the commissioning status of the primary frequency regulation and the working status of the generator. If so, the speed feedback value is set to the value obtained after the dead zone determination processing; otherwise, the speed feedback value is set to the difference value. The speed feedback value is then processed by adjustment value calculation to obtain the steam adjustment value.

[0060] Specifically, when the generator is in an abnormal state, such as when there is grid disturbance, the generator is in an off-load operation state, or the primary frequency regulation is cut off, the nuclear power plant is not suitable for primary frequency regulation. Therefore, there is no need to perform dead zone determination processing. In this case, the difference can be directly processed by adjustment value calculation. Conversely, when the primary frequency regulation is in operation and the generator is in a normal state, the difference needs to be processed by dead zone determination before adjustment value calculation.

[0061] In some embodiments, the dead zone determination process includes: if the difference is less than the lower dead zone threshold, setting the difference as the upper dead zone threshold; if the difference is greater than the upper dead zone threshold, setting the difference as the lower dead zone threshold. It is understood that the difference between the upper and lower dead zone thresholds constitutes the dead zone range. A smaller dead zone range results in more precise control of the nuclear power plant's generators, but also requires a higher frequency of frequency regulation. To avoid excessively frequent frequency regulation, the upper and lower dead zone thresholds need to be set based on actual operation. Optionally, the upper dead zone threshold is 0.16%, and the lower dead zone threshold is +0.16%.

[0062] In some embodiments, the adjustment value calculation process includes: dividing the difference by the rotational speed inequality rate and then performing PID calculation to calculate the steam adjustment value.

[0063] Step S3 includes: performing limit calculations on the actual load and steam adjustment value of the generator based on the generator's operating status and / or reactor power to obtain a second steam demand value.

[0064] In some embodiments, reference Figure 2 The limit value calculation process in step S3 includes steps S31, S32, S33, S34 and S35.

[0065] Step S31 includes: determining whether a limit needs to be set on the steam adjustment value based on the generator's operating status and / or reactor power. If so, proceed to step S32; otherwise, proceed to step S35.

[0066] Furthermore, in some embodiments, the determination in step S31 of whether to limit the steam adjustment value based on the generator's operating state and / or reactor power includes: determining that a limit on the steam adjustment value is needed when the generator is connected to the grid, and there are no grid disturbances or load shedding phenomena, and the reactor is at full power load; and determining that a limit on the steam adjustment value is not needed when the generator is not connected to the grid, or there are grid disturbances or load shedding phenomena. It is understood that the conditions for imposing a limit must be met: ensuring that the generator is connected to the grid, and in this state, there are no grid disturbances or load shedding phenomena, and the reactor is not at full power load.

[0067] Understandably, by executing step S31, it can be ensured that the steam adjustment value calculated after the dead zone determination process after the generator is connected to the grid will not be put into use immediately, but will be limited before being put into use, so as to avoid reducing the stability of the turbine generator set and reactor control system.

[0068] Step S32 includes: comparing the actual load according to a preset power range to obtain comparison data.

[0069] To ensure that the power variation of the generator load does not exceed the limit range during the limit setting process, thus complying with the nuclear power plant unit operation technical specifications, in some embodiments, the comparison processing in step S32 includes: subtracting the actual load from the upper limit of the preset power range to obtain a first comparison value; subtracting the actual load from the lower limit of the preset power range to obtain a second comparison value; the first comparison value and the second comparison value constitute the comparison data. Optionally, the upper limit of the preset power range is 100%, and the lower limit of the preset power range is 30%. Further, the preset power range can be modified online according to the season (summer or winter) and the reactor power situation; wherein, adjusting the upper limit (100% or other values) can prevent the reactor from exceeding its power limit, and adjusting the lower limit (30% or other values) can prevent the impact on the stability of the turbine generator set and reactor control.

[0070] Step S33 includes: performing limit processing on the comparison data to obtain the limit range.

[0071] In some embodiments, the limit processing in step S33 includes: taking the larger of a first preset comparison value and a first comparison value as the first larger value, and setting the smaller of a preset upper limit value and the first larger value as the upper limit of the limit range; taking the smaller of a second preset comparison value and a second comparison value as the first smaller value, and setting the larger of a preset lower limit value and the first smaller value as the lower limit of the limit range. Optionally, the first preset comparison value and the second preset comparison value are 0%, the preset upper limit value is 3%, and the preset lower limit value is -3%. The preset upper limit value and the preset lower limit value can be modified online according to the reactor design capacity and grid technical specifications. A larger effective value for the preset upper limit value and the preset lower limit value indicates a stronger ability to participate in primary frequency regulation, but it is detrimental to the reactor power control because excessively large values ​​may violate the unit operation technical specifications.

[0072] Step S34 includes: setting a second steam demand value based on the limit range and steam adjustment value, and then executing step S4;

[0073] In some embodiments, S34 includes:

[0074] If the steam adjustment value is within the limit range, the second steam demand value is set to the steam adjustment value; if the steam adjustment value is less than the lower limit of the limit range, the second steam demand value is set to the lower limit of the limit range; if the steam adjustment value is greater than the upper limit of the limit range, the second steam demand value is set to the upper limit of the limit range, and S4 is executed.

[0075] Specifically, the working principle of steps S32 to S34 is as follows: based on the preset power range upper limit of 100%, preset power range lower limit of 30%, limit range upper limit of 3%, and limit range lower limit of -3% settings:

[0076] A. Taking an actual load of 101% as an example, after executing step S32, the first comparison value is -1% and the second comparison value is -71%. Then, after executing step S33, the upper limit of the limit range is 0% (the first larger value is 0%) and the lower limit of the limit range is -3% (the first smaller value is -71%). Therefore, the final second steam demand value will be limited to the range of 0% to 3%. It can be understood that by executing steps 32 to S34, the steam adjustment value can be limited when the primary frequency regulation exceeds 100% of the power, ensuring that the primary frequency regulation no longer operates in the positive direction when the actual load is 100%, thereby avoiding reactor over-power operation.

[0077] B. Taking an actual load of 29% as an example, after executing step S32, the first comparison value is obtained as 71%, and the second comparison value is as 1%. Then, after executing step S33, the upper limit of the limit range is obtained as 3% (the first larger value is 71%), and the lower limit of the limit range is as 0% (the first smaller value is 0%). Therefore, the final second steam demand value will be limited to the range of 0% to 3%. It can be understood that by executing steps 32 to S34, the steam adjustment value can be limited when the power of the primary frequency regulation does not exceed 30%, so as to ensure that the operation of the primary frequency regulation is in the state of increasing load.

[0078] C. In summary, in this embodiment, executing steps S32 to S34 can make the primary frequency regulation only effective between 30% and 100% of the power, and can also limit the power adjustment amplitude (limited to the range of -3% to 3%), thereby improving the stability and reliability of the turbine generator set and reactor control system.

[0079] Step S35 includes: setting the second steam demand value to the steam adjustment value, and then executing step S4.

[0080] Step S4 includes: calculating the total steam demand value based on the first steam demand value and the second steam demand value, and then returning to S2.

[0081] refer to Figure 3 The present invention also provides a primary frequency regulation control system for a nuclear power plant, used to calculate the total steam demand value for controlling the generator speed of the nuclear power plant, including a first calculation unit 1, a second calculation unit 2, a limit calculation unit 3 and a total steam demand value calculation unit 4.

[0082] The first arithmetic unit 1 is used to perform a first arithmetic processing on the target speed of the generator to generate a first steam demand value.

[0083] The second calculation unit 2 is used to obtain the actual speed of the generator and perform a second calculation based on the actual speed and the target speed to generate a steam adjustment value.

[0084] Limit calculation unit 3 is used to perform limit calculations on the actual load and steam adjustment value of the generator based on the generator's operating status and / or reactor power, and generate a second steam demand value.

[0085] The total steam demand calculation unit 4 is used to calculate the total steam demand value based on the first steam demand value and the second steam demand value. Specifically, the total steam demand calculation unit 4 is an adder that adds the first steam demand value and the second steam demand value to obtain the total steam demand value.

[0086] In some embodiments, such as Figure 4 As shown, the second arithmetic unit 2 includes a third subtractor 21, a second state judgment unit 22, a second switching unit 23, a dead zone judgment and processing unit 24, a divider 25, and a PID arithmetic unit 26.

[0087] The third subtractor 21 is used to calculate the difference between the target speed and the actual speed.

[0088] The second state judgment unit 22 is used to control the operation of the second switching unit 23 according to the commissioning status of the primary frequency regulation and the working status of the generator.

[0089] The second switching unit 23 can be a switching switch. When its control terminal inputs logic "1" (primary frequency regulation is in operation and the generator is in normal grid connection state), the upper circuit of the switching switch is closed, which corresponds to: the output value of the dead zone determination and processing unit 24 is used as the difference output; otherwise, the lower circuit of the switching switch is closed (e.g., ...). Figure 4 The following corresponds to the case of closing the loop again, which means: the difference between the target speed and the actual speed is directly output to the divider 25.

[0090] The dead zone determination processing unit 24 is used to perform dead zone determination processing on the difference between the target speed and the actual speed.

[0091] The first end of the divider 25 is connected to the output end of the second switching unit 23, and the second end of the divider 25 is used to input the speed unequal rate. The divider 25 is used to divide the difference by the speed unequal rate.

[0092] The PID operator 26 is used to perform PID calculations on the output value of the divider 25 and output the steam adjustment value.

[0093] In some embodiments, such as Figure 4 As shown, the limit value calculation unit 3 includes a first state judgment unit 31, a first switching unit 32, and a limit value unit.

[0094] Specifically, the first state judgment unit 31 is used to determine whether the steam adjustment value needs to be limited based on the generator's operating state and / or reactor power, and transmits the judgment result to the first switching unit 32; the first switching unit 32 sets the second steam demand value to the limit value or steam adjustment value output by the limit unit based on the judgment result.

[0095] Furthermore, the limit unit includes a comparison processing unit 331, a limit range setting unit 332, and an output unit 333; the comparison processing unit 331 is used to compare the actual load according to the preset power range and generate comparison data; the limit range setting unit 332 is used to perform limit processing on the comparison data and generate a limit range; the output unit 333 is used to output the limit value according to the limit range and the steam adjustment value.

[0096] In some embodiments, such as Figure 4 As shown, the first state judgment unit 31 includes a first AND gate 311, a first OR gate 312, and a first NOT gate 313. The first input terminal of the first AND gate 311 is used to receive the generator grid connection status signal (this signal is set to "1" when the generator is connected to the grid and can be issued by the turbine generator set). The input terminal of the first OR gate 312 is used to receive the generator grid disturbance feedback signal (this signal is set to "1" when grid disturbance occurs and can be issued by the turbine generator set), the load shedding feedback signal (this signal is set to "1" when load shedding occurs and can be issued by the turbine generator set), and the reactor power status signal (this signal is set to "1" when the reactor is at full power load and can be issued by the reactor control system set). The output terminal of the first OR gate 312 is connected to the input terminal of the first NOT gate 313, the output terminal of the first NOT gate 313 is connected to the second input terminal of the first AND gate 311, and the output terminal of the first AND gate 311 is connected to the limit calculation unit 3 to send the judgment result to the first switching unit 32.

[0097] In some embodiments, the first switching unit 32 can be a switching switch. When its control terminal receives a logic "1", the upper circuit of the switching switch is closed, which corresponds to setting the second steam demand value to the limit value output by the limit unit; conversely, the lower circuit of the switching switch is closed (e.g., ...). Figure 4 The following corresponds to the case of closing the circuit again, which means: setting the second steam demand value to the steam adjustment value.

[0098] In some embodiments, such as Figure 4 As shown, the comparison processing unit 331 includes a first subtractor 3311 and a second subtractor 3312.

[0099] Specifically, the first input terminal of the first subtractor 3311 is used to receive the upper limit value of the preset power range, and the second input terminal of the first subtractor 3311 is used to receive the actual load, so as to subtract the actual load from the upper limit value of the preset power range to obtain the first comparison value; the output terminal of the first subtractor 3311 is connected to the limit range setting unit 332, and then sends the first comparison value to the limit range setting unit 332.

[0100] The first input terminal of the second subtractor 3312 is used to receive the lower limit value of the preset power range, and the second input terminal of the second subtractor 3312 is used to receive the actual load, so as to subtract the lower limit value of the preset power range from the actual load to obtain the second comparison value; the output terminal of the second subtractor 3312 is connected to the limit range setting unit 332, and then the second comparison value is sent to the limit range setting unit 332.

[0101] In some embodiments, such as Figure 4 As shown, the limit range setting unit 332 includes a first larger value unit 3321, a first smaller value unit 3322, a second smaller value unit 3323, and a second larger value unit 3324.

[0102] The first input terminal of the first large-value unit 3321 is connected to the output terminal of the first subtractor 3311 to receive a first comparison value. The second input terminal of the first large-value unit 3321 is used to receive a first preset comparison value. The first large-value unit 3321 is used to extract the larger value between the first preset comparison value and the first comparison value as the first large value. The output terminal of the first large-value unit 3321 is connected to the second input terminal of the first small-value unit 3322 to send the first large value to the first small-value unit 3322. The first input terminal of the first small-value unit 3322 is used to receive a preset upper limit value. The first small-value unit 3322 is used to extract the smaller value between the first large value and the preset upper limit value. The output terminal of the first small-value unit 3322 is connected to the output unit 333 to send the smaller value between the first large value and the preset upper limit value to the output unit 333.

[0103] The first input terminal of the second smaller unit 3323 is connected to the output terminal of the second subtractor 3312 to receive the second comparison value. The second input terminal of the second smaller unit 3323 is used to receive the second preset comparison value. The second smaller unit 3323 is used to extract the smaller value between the second comparison value and the second preset comparison value as the first smaller value. The output terminal of the second smaller unit 3323 is connected to the first input terminal of the second larger unit 3324 to send the first smaller value to the second larger unit 3324. The second input terminal of the second larger unit 3324 is used to receive the preset lower limit value. The second larger unit 3324 is used to extract the larger value between the first smaller value and the preset lower limit value. The output terminal of the second larger unit 3324 is connected to the output unit 333 to send the larger value between the first smaller value and the preset lower limit value to the output unit 333.

[0104] In some embodiments, such as Figure 4 As shown, the output unit 333 includes a limiting unit. Specifically, the upper limit setting terminal of the limiting unit is connected to the output terminal of the first smaller value unit 3322 to set the smaller of the first larger value and the preset upper limit value as the upper limit value of the limit range. The lower limit setting terminal of the limiting unit is connected to the output terminal of the second larger value unit 3324 to set the larger of the first smaller value and the preset lower limit value as the lower limit value of the limit range. The input terminal of the limiting unit is connected to the second calculation unit 2 to receive the steam adjustment value, and the output terminal of the limiting unit is connected to the first switching unit 32. The limiting unit is used to output the steam adjustment value as the second steam demand value when the steam adjustment value is within the limit range; output the lower limit value of the limit range as the second steam demand value when the steam adjustment value is less than the lower limit value of the limit range; and output the upper limit value of the limit range as the second steam demand value when the steam adjustment value is greater than the upper limit value of the limit range.

[0105] This invention provides at least the following beneficial effects: It offers a primary frequency regulation control method for nuclear power plants. This method involves performing a first calculation on the target speed of the generator to obtain a first steam demand value; simultaneously acquiring the actual speed of the generator and performing a second calculation based on the actual and target speeds to obtain a steam adjustment value; then, performing a limit calculation on the actual load of the generator and the steam adjustment value based on the generator's operating state and / or reactor power to obtain a second steam demand value; and finally, calculating the total steam demand value based on the first and second steam demand values. Implementing this invention can prevent the primary frequency regulation from continuing to operate forward when the generator or reactor is at full power load, thus avoiding reactor over-power situations. It also avoids excessive load fluctuations during primary frequency regulation that could violate unit operation specifications, and prevents overly frequent frequency regulation operations. Furthermore, it avoids immediate operation of primary frequency regulation after the generator is connected to the grid, thereby improving the stability of the turbine generator set and reactor control system.

[0106] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A primary frequency regulation control method for a nuclear power plant, used to calculate the total steam demand of the nuclear power plant's turbine generator unit, characterized in that, Includes the following steps: S1. Perform the first calculation on the target speed of the generator to obtain the first steam demand value; S2. Obtain the actual speed of the generator, and perform a second calculation based on the actual speed and the target speed to obtain the steam adjustment value; S3. Based on the operating status of the generator and / or the reactor power, perform limit calculations on the actual load of the generator and the steam adjustment value to obtain a second steam demand value. S4. Calculate the total steam demand value based on the first steam demand value and the second steam demand value, and return to S2; In S3, the limit value calculation process includes: S31. Determine whether it is necessary to limit the steam adjustment value based on the operating status of the generator and / or the reactor power. If yes, proceed to step S32; otherwise, proceed to step S35. S32. Compare the actual load according to the preset power range to obtain comparison data; S33. Perform limit processing on the comparison data to obtain the limit range; S34. Set the second steam demand value according to the limit range and the steam adjustment value, and execute S4. S35. Set the second steam demand value to the steam adjustment value and execute S4.

2. The primary frequency regulation control method for nuclear power plants according to claim 1, characterized in that, In step S31, determining whether a limit needs to be imposed on the steam adjustment value based on the generator's operating status and / or the reactor power includes: When the generator is connected to the grid, and there are no grid disturbances or load shedding phenomena, and the reactor is at full power load, it is determined that the steam adjustment value needs to be limited; when the generator is not connected to the grid, or there are grid disturbances or load shedding phenomena, it is determined that the steam adjustment value does not need to be limited.

3. The primary frequency regulation control method for nuclear power plants according to claim 2, characterized in that, In S32, the comparison process includes: The first comparison value is obtained by subtracting the actual load from the upper limit of the preset power range; the second comparison value is obtained by subtracting the actual load from the lower limit of the preset power range; the first comparison value and the second comparison value constitute the comparison data.

4. The primary frequency regulation control method for nuclear power plants according to claim 3, characterized in that, In S33, the limit processing includes: The larger of the first preset comparison value and the first comparison value is taken as the first larger value, and the smaller of the preset upper limit value and the first larger value is set as the upper limit value of the limit range; The smaller of the second preset comparison value and the second comparison value is taken as the first smaller value, and the larger of the preset lower limit value and the first smaller value is set as the lower limit value of the limit range.

5. The primary frequency regulation control method for nuclear power plants according to claim 4, characterized in that, S34 includes: If the steam adjustment value is within the limit range, then the second steam demand value is set to the steam adjustment value; if the steam adjustment value is less than the lower limit of the limit range, then the second steam demand value is set to the lower limit of the limit range; if the steam adjustment value is greater than the upper limit of the limit range, then the second steam demand value is set to the upper limit of the limit range, and step S4 is executed.

6. The primary frequency regulation control method for nuclear power plants according to claim 5, characterized in that, In S2, the second arithmetic process includes: Calculate the difference between the target speed and the actual speed, and determine whether to perform dead zone determination processing based on the commissioning status of the primary frequency regulation and the working status of the generator. If so, set the speed feedback value to the value obtained after the dead zone determination processing; otherwise, set the speed feedback value to the difference. The steam adjustment value is obtained by performing adjustment value calculation on the speed feedback value.

7. A primary frequency regulation control system for a nuclear power plant, used to calculate the total steam demand of the nuclear power plant's turbine generator unit, characterized in that... include: The first calculation unit (1) is used to perform a first calculation on the target speed of the generator to generate a first steam demand value; The second calculation unit (2) is used to obtain the actual speed of the generator and perform a second calculation based on the actual speed and the target speed to generate a steam adjustment value; The limit calculation unit (3) is used to perform limit calculation processing on the actual load of the generator and the steam adjustment value according to the working status of the generator and / or the reactor power, and generate a second steam demand value. The total steam demand calculation unit (4) is used to calculate the total steam demand value based on the first steam demand value and the second steam demand value. The limit value calculation unit (3) includes a first state judgment unit (31), a first switching unit (32), and a limit value unit; The first state judgment unit (31) is used to determine whether the steam adjustment value needs to be limited based on the working state of the generator and / or the reactor power, and transmit the judgment result to the first switching unit (32). The first switching unit (32) sets the second steam demand value to the limit value output by the limit unit or the steam adjustment value according to the judgment result; The limit unit includes a comparison processing unit (331), a limit range setting unit (332), and an output unit (333). The comparison processing unit (331) is used to compare the actual load according to a preset power range and generate comparison data; The limit range setting unit (332) is used to perform limit processing on the comparison data and generate a limit range; The output unit (333) is used to output the limit value according to the limit range and the steam adjustment value.

8. The primary frequency control system for nuclear power plants according to claim 7, characterized in that, The first state judgment unit (31) includes a first AND gate (311), a first OR gate (312), and a first NOT gate (313). The first input terminal of the first AND gate (311) is used to receive the grid connection status signal of the generator. The input terminal of the first OR gate (312) is used to receive the grid disturbance feedback signal, load shedding feedback signal, and reactor power status signal of the generator. The output terminal of the first OR gate (312) is connected to the input terminal of the first NOT gate (313). The output terminal of the first NOT gate (313) is connected to the second input terminal of the first AND gate (311). The output terminal of the first AND gate (311) is connected to the limit calculation unit (3) to send the judgment result to the first switching unit (32).

9. The primary frequency control system for a nuclear power plant according to claim 8, characterized in that, The comparison processing unit (331) includes a first subtractor (3311) and a second subtractor (3312). The first input terminal of the first subtractor (3311) is used to receive the upper limit value of the preset power range, the second input terminal of the first subtractor (3311) is used to receive the actual load, and the output terminal of the first subtractor (3311) is connected to the limit range setting unit (332). The first input terminal of the second subtractor (3312) is used to receive the lower limit value of the preset power range, the second input terminal of the second subtractor (3312) is used to receive the actual load, and the output terminal of the second subtractor (3312) is connected to the limit range setting unit (332).

10. The primary frequency control system for a nuclear power plant according to claim 9, characterized in that, The limit range setting unit (332) includes a first larger unit (3321), a first smaller unit (3322), a second smaller unit (3323), and a second larger unit (3324). The first input terminal of the first large-scale unit (3321) is connected to the output terminal of the first subtractor (3311), the second input terminal of the first large-scale unit (3321) is used to receive a first preset comparison value, the output terminal of the first large-scale unit (3321) is connected to the second input terminal of the first small-scale unit (3322), the first input terminal of the first small-scale unit (3322) is used to receive a preset upper limit value, and the output terminal of the first small-scale unit (3322) is connected to the output unit (333). The first input terminal of the second smaller unit (3323) is connected to the output terminal of the second subtractor (3312), the second input terminal of the second smaller unit (3323) is used to receive a second preset comparison value, the output terminal of the second smaller unit (3323) is connected to the first input terminal of the second larger unit (3324), the second input terminal of the second larger unit (3324) is used to receive a preset lower limit value, and the output terminal of the second larger unit (3324) is connected to the output unit (333).

11. The primary frequency control system for a nuclear power plant according to claim 10, characterized in that, The output unit (333) includes a limiting unit; The upper limit setting terminal of the limiting unit is connected to the output terminal of the first smaller value unit (3322), the lower limit setting terminal of the limiting unit is connected to the output terminal of the second larger value unit (3324), the input terminal of the limiting unit is connected to the second arithmetic unit (2), and the output terminal of the limiting unit is connected to the first switching unit (32).

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