CN110566288A - Primary frequency modulation system and method for steam turbine set of nuclear power station - Google Patents
Primary frequency modulation system and method for steam turbine set of nuclear power station Download PDFInfo
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- CN110566288A CN110566288A CN201910894092.5A CN201910894092A CN110566288A CN 110566288 A CN110566288 A CN 110566288A CN 201910894092 A CN201910894092 A CN 201910894092A CN 110566288 A CN110566288 A CN 110566288A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D17/00—Regulating or controlling by varying flow
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D17/00—Regulating or controlling by varying flow
- F01D17/10—Final actuators
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Abstract
The invention discloses a primary frequency modulation system and a primary frequency modulation method for a steam turbine set of a nuclear power station.A temperature sensor converts temperature information of a loop of the nuclear power station into a first analog electric signal; the first acquisition module acquires the first analog electric signal and performs analog-to-digital conversion to obtain a first digital electric signal; the first calculation module calculates a thermal power value; the signal transmission module transmits the thermal power value; the first output module converts the thermal power value into a second analog electric signal to be output; the second acquisition module acquires a second analog electric signal and performs analog-to-digital conversion to obtain a second digital electric signal; the second calculation module is combined with the second digital electric signal to calculate the upper limit value of the primary frequency modulation capacity; the second output module converts the primary frequency modulation capacity upper limit value into a third analog electric signal; and the main valve electromagnetic valve adjusts the opening degree of a main valve of the steam turbine under the control of the third analog electric signal. The primary frequency modulation system and the method can avoid the nuclear safety risk caused by the fact that the unit still responds to the primary frequency modulation of the power grid under the condition that the thermal power is over-limit.
Description
Technical Field
the invention relates to the technical field of primary frequency modulation of nuclear power units, in particular to a primary frequency modulation system and method of a steam turbine unit of a nuclear power station.
background
the CPR1000 is the nuclear power technical proposal of the Chinese improved million kilowatt pressurized water reactor released by the Guankari group of China. The design rated electric power of the CPR1000 nuclear power unit is 1086MWe (megawatt electric power), and the corresponding thermal power of a primary circuit is 2905 MWe. In order to ensure the power supply quality of the power grid, all the networked generator sets need to participate in the primary frequency modulation of the power grid so as to deal with the power grid load change generated by the power grid in an untimely way. However, the response to the primary frequency modulation of the power grid cannot exceed the rated power of the unit, so in design, the maximum electric power of the CPR1000 nuclear power unit responding to the primary frequency modulation of the power grid is 54.3WMe, the maximum electric power is 1086MWe, and if the maximum electric power exceeds the regulation range of the unit, the fixed electric power output is kept.
The inventor finds that in summer, the temperature of seawater rises and exceeds 30 ℃, the efficiency of a steam turbine generator is obviously reduced, so that under the condition of the same primary loop thermal power 2905MWe, the electric power generated by a unit is 1060-1070 MWe and is lower than a design value 1086MWe, under the condition, the unit does not reach the response upper limit of primary frequency modulation of a power grid, a response space of 15-20 MWe still exists, if the unit responds to the primary frequency modulation of the power grid, the power of the steam turbine is automatically increased, the primary loop thermal power is directly caused to exceed the 2905MWe design value, serious threats are caused to reactor core nuclear fuel and a primary loop pressure boundary, and a large nuclear safety risk exists.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
disclosure of Invention
The invention aims to provide a primary frequency modulation system and a primary frequency modulation method for a steam turbine set of a nuclear power station, which effectively avoid potential nuclear safety risks caused by the fact that the set still responds to primary frequency modulation of a power grid under the condition of thermal power overrun.
In order to achieve the above object, the present invention provides a primary frequency modulation system for a steam turbine set of a nuclear power plant, comprising: the temperature sensor, the first acquisition module, the first calculation module, the signal transmission module, the first output module, the second acquisition module, the second calculation module, the second output module and the main valve electromagnetic valve. The temperature sensor is connected in a loop of the nuclear power station and used for converting temperature information of the loop of the nuclear power station into a first analog electric signal; the first acquisition module is connected with the temperature sensor and used for acquiring the first analog electric signal and performing analog-to-digital conversion to obtain a first digital electric signal; the first calculation module is connected with the first acquisition module and used for calculating the heat power value of the loop of the nuclear power station according to the first digital electric signal; the signal transmission module is connected with the first calculation module and is used for transmitting the thermal power value; the first output module is connected with the signal transmission module and used for converting the thermal power value into a second analog electric signal to be output; the second acquisition module is connected with the first output module and used for acquiring the second analog electric signal and performing analog-to-digital conversion to obtain a second digital electric signal; the second calculation module is connected with the second acquisition module and used for calculating the upper limit value of the primary frequency modulation capacity by combining the second digital electric signal; the second output module is connected with the second calculation module and used for converting the primary frequency modulation capacity upper limit value into a third analog electric signal; and the main valve electromagnetic valve is connected with the second output module and is used for adjusting the opening of a main valve of the steam turbine under the control of the third analog electric signal.
In an embodiment of the present invention, the second calculation module includes: the device comprises a first comparison module, a second comparison module, a third comparison module and a fourth comparison module. The first comparison module is connected with the second acquisition module and used for comparing the difference value between the upper limit value of the loop thermal power and the second digital electric signal with 0 and outputting a larger value serving as a first comparison result; the second comparison module is used for comparing the difference value between the rated power of the steam turbine and the set value of the load of the steam turbine with 0, and taking the larger value as a second comparison result to output; the third comparison module is connected with the first comparison module and the second comparison module and used for comparing the first comparison result, the second comparison result and the maximum value of the primary frequency modulation capacity, and a smaller value is taken as a third comparison result to be output; and the fourth comparison module is connected with the third comparison module and used for comparing the third comparison result with 0, and taking the smaller value as the upper limit value of the primary frequency modulation capacity to output.
in one embodiment of the present invention, the maximum primary modulation capacity is 5% of the rated power of the steam turbine set.
in an embodiment of the present invention, the first acquisition module, the first calculation module, the signal transmission module, and the first output module are all disposed in a non-safety-level digital instrumentation and control system of a whole plant of a nuclear power plant, wherein the first acquisition module is an analog input acquisition card, the first calculation module is a CPU, the signal transmission module is a signal transmission channel between two field control stations, and the first output module is an analog output card.
In an embodiment of the present invention, the second acquisition module, the second calculation module, and the second output module are all disposed in a steam turbine control system of a nuclear power plant, wherein the second acquisition module is an analog input acquisition card, the second calculation module is a CPU, and the first output module is an analog output card.
in one embodiment of the present invention, the first analog electrical signal and the second analog electrical signal are currents having a value range of 4 to 20 mA.
The invention also provides a primary frequency modulation method for the steam turbine set of the nuclear power station, which comprises the following steps: converting the temperature information of the loop of the nuclear power station into a first analog electric signal; collecting the first analog electric signal, and performing analog-to-digital conversion to obtain a first digital electric signal; calculating the thermal power value of the loop of the nuclear power plant according to the first digital electric signal; converting the thermal power value into a second analog electric signal to be output; collecting the second analog electric signal, and performing analog-to-digital conversion to obtain a second digital electric signal; calculating the upper limit value of the primary frequency modulation capacity by combining the second digital electric signal; converting the primary frequency modulation capacity upper limit value into a third analog electric signal; and adjusting the opening degree of a main valve of the steam turbine under the control of the third analog electric signal.
In an embodiment of the present invention, the calculating the upper limit value of the primary modulation capacity by combining the second digital electric signal includes: comparing the difference value between the upper limit value of the loop thermal power and the second digital electric signal with 0, and taking the larger value as a first comparison result to output; comparing the difference value between the rated power of the steam turbine and the set value of the load of the steam turbine with 0, and taking the larger value as a second comparison result to output; comparing the first comparison result, the second comparison result and the maximum value of the primary frequency modulation capacity, and taking the smaller value as a third comparison result to output; and comparing the third comparison result with 0, and taking the smaller value as the upper limit value of the primary frequency modulation capacity to output.
In one embodiment of the present invention, the maximum primary modulation capacity is 5% of the rated power of the steam turbine set.
in one embodiment of the present invention, the first analog electrical signal and the second analog electrical signal are currents having a value range of 4 to 20 mA.
Compared with the prior art, according to the primary frequency modulation system and the method for the steam turbine set of the nuclear power station, a primary circuit thermal power condition is introduced into primary frequency modulation capacity upper limit control to serve as a limiting condition of the primary frequency modulation capacity upper limit control, when the temperature of seawater rises in summer to cause the efficiency of a steam turbine to be reduced, when a secondary circuit reaches full power, even if the temperature of the secondary circuit does not reach 1086MWe, a primary frequency modulation up-regulation space still exists, the primary frequency modulation up-regulation space responds according to the current primary circuit thermal power condition of the steam turbine set, if the primary circuit thermal power reaches 2905MWe, the primary frequency modulation up-regulation is not continued, the primary circuit thermal power is guaranteed not to exceed the limit value, and potential nuclear safety risks caused by the fact that the steam turbine set still responds to.
Drawings
FIG. 1 is a functional schematic of a primary frequency modulation according to the prior art;
FIG. 2 is a schematic diagram of primary frequency modulation dead band setting and maximum regulation load limit according to the prior art;
FIG. 3 is a schematic diagram of a primary FM capacity ceiling limit module according to the prior art;
FIG. 4 is a schematic diagram of a primary frequency modulation capacity upper limit limiting module according to an embodiment of the invention;
FIG. 5 is a block diagram of a primary frequency modulation system of a steam turbine set of a nuclear power plant according to an embodiment of the present invention;
fig. 6 is a step composition of primary frequency modulation of a steam turbine set of a nuclear power plant according to an embodiment of the present invention.
Detailed Description
The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.
Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.
In order to overcome the problems of the prior art, the inventors conducted the following analysis in implementing the present invention.
CPR1000 nuclear power unitAnd finally, the opening of a steam turbine valve is controlled through the effective steam demand, and a primary frequency modulation function of the steam turbine is added to an effective load setting value module to participate in the control of the rotating speed load of the unit. The principle of primary frequency modulation is shown in fig. 1. The difference between the set value NS and the actual value NT is called the difference (delta n) and is sent out in two paths. One path of the feedforward signal is used as one of feedforward signals for calculating the steam demand to participate in calculation, and the other path of the feedforward signal is used as the input of a primary frequency modulation module. The output of the primary frequency modulation module is called primary frequency modulation component, the component calculates load deviation with a steam turbine load set value PS and a steam turbine actual load value PEL, and the load deviation is calculated through a PI controller and a frequency difference feedforward KDNAnd power feedforward KPThe steam demand SD is obtained.
In order to avoid that the unit deviates from normal operation and transient operation to cause overlarge and too fast load change and further endanger the safe and stable operation of the nuclear power unit, according to the primary frequency modulation function requirement of a power grid and the control requirement of CPR1000 nuclear power unit pile-machine matching, the primary frequency modulation parameters of the nuclear power unit are required to ensure reactor control as the primary target, and a dead zone range suitable for reactor power change and a maximum modulation load limit value of primary frequency modulation are set. When the rotating speed (frequency) changes in the dead zone, the primary frequency modulation does not act; when the change of the rotating speed (frequency) exceeds the dead zone range, the primary frequency modulation module adjusts the load and the frequency according to the power frequency characteristic and is limited by the maximum load change. The primary frequency modulation dead band setting and maximum regulation load limit are shown in fig. 2. Wherein, the primary frequency modulation dead zone is +/-2 r/min, and the maximum frequency modulation power modulation capacity is +/-54.3 MWe (+/-5% of the rated electric power of the steam turbine); when the rotating speed is less than 1498rpm, the maximum power-rise value is 54.3MWe when the rotating speed is reduced to 1494.25rpm by the variable power-rise of delta n steam turbine rated power/(steam turbine rated rotating speed 5%); (the rotating speed difference delta n is the rated rotating speed of the steam turbine 1500 r/min-the current rotating speed of the steam turbine); when the electric power is more than 1086MW, the load-up is not allowed to carry out primary frequency modulation, and the primary frequency modulation does not allow the electric power to exceed 1086 MW; when the rotating speed is more than 1502rpm, reducing the power by the variable quantity of delta n per rated power of the steam turbine/(rated rotating speed of the steam turbine 5%), and when the rotating speed is more than 1505.75rpm, reaching the maximum power reduction value of-54.3 MWe; when the rotating speed continues to rise to 1515rpm, the frequency modulation output is limited to output; when the rotating speed is increased to 1518.75rpm, the frequency modulation output limitation is acted, the power of the unit is continuously reduced by 5% of unequal rate until the maximum power reduction value reaches-200 MW when the rotating speed is more than 1528.12; when the electric power is less than 162.9MW, the load reduction is not allowed to carry out primary frequency modulation.
Fig. 3 is a schematic diagram of a primary frequency modulation capacity upper limit limiting module. The primary frequency modulation capacity upper limit control principle is that the difference between the rated power P0 of the steam turbine and the current load set value Psw of the steam turbine is compared with 0, the larger value of the difference is taken as the output, the output is compared with the primary frequency modulation upper limit capacity 54.3MWe, and the smaller value of the output is taken as the primary frequency modulation component of the final steam turbine power up modulation. For example, when the turbine rated power P0 is 1086MWe, the current load set value Psw is 1076MWe, and the difference between them is 10MWe, which is greater than 0 but smaller than 54.3MWe, then 10MWe is the primary frequency modulation component, and participates in the actual steam demand calculation. If Psw is 1090MWe, the difference between the Psw and the MWe is-4 MWe and is smaller than 0, 0 is output after the Psw and the MWe are compared with 0, and the primary frequency modulation component is 0MWe, namely when the actual power of the unit is larger than the rated power, the unit does not participate in primary frequency modulation operation.
through the analysis of the inventor, the inventor finds that the conventional primary frequency modulation design scheme of the CPR1000 nuclear power unit only adopts the design logic that the steam turbine power does not exceed the rated upper limit of the two loops, and does not limit the upper limit of the power of the one loop. When the thermal efficiency of the unit is reduced and the output power does not reach the rated value 1086MWe, the primary frequency modulation is adjusted up, and the situation of primary circuit overpower may occur. For example, in summer, the temperature of seawater rises, the efficiency of a steam turbine is reduced, the actual power of a secondary loop is 1060-1070 MWe when the thermal power of a primary loop of a CPR1000 unit reaches 2905MWe, the primary frequency modulation component still has 5-25 MWe of adjustment margin according to the control principle of the upper limit value of the primary frequency modulation capacity introduced above, if the unit participates in primary frequency modulation operation, the primary loop is directly over-powered, the pressure boundary of the primary loop and a fuel cladding are seriously threatened, and the nuclear safety is seriously influenced.
Based on the above research, in order to solve the above problems, the present invention introduces a loop thermal power condition in the primary fm upper limit control as a limiting condition of the primary fm upper limit control, and a schematic diagram of the primary fm upper limit value calculation is shown in fig. 4. Specifically, the upper limit of the primary modulation capacity is 3 limiting conditions. The first limiting condition is the maximum value of the primary frequency modulation capacity, and the rated power of the unit is taken to be 5 percent and is 54.3 MWe; the second limiting condition is that the difference between the rated power P0 of the steam turbine and the current load set value Psw of the steam turbine is compared with 0, and the larger value is taken as output; the third constraint is that the difference between the upper limit of the thermal power (2905MWe) of the primary circuit and the current value of the thermal power Pr of the primary circuit is compared with 0, and the larger value is taken as the output.
and comparing the outputs of the three conditions, and taking the minimum value of the three conditions as the primary frequency modulation component output to participate in the calculation of the actual steam demand. For example, if the difference between the turbine rated power P0 and the current load set value Psw is 1086MWe and 1076MWe in the second limiting condition is 10MWe, the output of the second limiting condition is 10 MWe. The current thermal power in the third constraint is 2890MWe, the difference between the two is 15MWe, and is greater than 0, then the output of the third constraint is 15MWe, the output of the three constraints is the minimum output, and then the primary frequency modulation component is 10 MWe. For another example, on the premise of the second constraint condition, if the loop rated thermal power in the third constraint condition is 2905MWE, the current thermal power is 2900MWE, the difference between the two is 5MWE, and is greater than 0, the output of the third constraint condition is 5MWE, and the minimum output of the outputs of the three constraint conditions is taken, so that the primary frequency modulation component is 5 MWE. For another example, still under the second constraint, if the current thermal power of the circuit in the third constraint is 2905MWe, the difference between the two is 0, and the output of the third constraint is also 0, the primary frequency modulation component is 0MWe, that is, the primary frequency modulation component does not participate in the primary power modulation operation.
It can be seen from the above analysis that, after a loop heat power value is introduced as a primary frequency modulation capacity limit control condition, the condition about steam turbine power limit in the original control principle is not changed, and the maximum value of the primary frequency modulation capacity upper limit is not changed. Meanwhile, the problem that when the actual power of a machine unit does not reach the rated power and the thermal power of a loop reaches the rated power value, the machine unit participates in primary frequency modulation to cause the thermal power of the loop to exceed the limit is solved. When the power of the steam engine in the second loop and the heat power of the first loop do not reach the rated power, the calculation output of the primary frequency modulation component of the steam engine in the second loop takes the smaller power difference of the power of the steam engine in the first loop as the primary frequency modulation component to participate in the calculation of the actual steam demand.
Based on the principle of frequency modulation capacity control, the invention provides a primary frequency modulation system and a primary frequency modulation method of a nuclear power unit from the practical application of a CPR1000 nuclear power unit, wherein a design limit 2905MWe of the thermal power of a primary circuit of the nuclear power station is used as one of limiting conditions of the unit in response to the primary frequency modulation of a power grid, namely, in summer, the thermal efficiency of the unit is reduced, when the unit runs at full power and must respond to the primary frequency modulation of the power grid, the thermal power of the primary circuit is not limited by the thermal power of the primary circuit and does not participate in regulation, the thermal power of the primary circuit is ensured not to exceed the design value, and the safety.
Fig. 5 is a primary frequency modulation system of a steam turbine set of a nuclear power plant according to an embodiment of the present invention, which includes: the temperature sensor 10, the first acquisition module 11, the first calculation module 12, the signal transmission module 13, the first output module 14, the second acquisition module 15, the second calculation module 16, the second output module 17, and the main valve solenoid valve 18.
the temperature sensor 10 is connected in a loop of the nuclear power plant and is used for converting temperature information of the loop of the nuclear power plant into a first analog electrical signal.
the first collecting module 11 is connected to the temperature sensor 10 and configured to collect a first analog electrical signal and perform analog-to-digital conversion to obtain a first digital electrical signal.
The first calculating module 12 is connected to the first collecting module 11, and is configured to calculate a thermal power value of a loop of the nuclear power plant according to the first digital electrical signal.
the signal transmission module 13 is connected to the first calculation module 12, and is configured to transmit the thermal power value.
The first output module 14 is connected to the signal transmission module 13, and is configured to convert the thermal power value into a second analog electrical signal for output.
The second collecting module 15 is connected to the first output module 14, and is configured to collect the second analog electrical signal and perform analog-to-digital conversion to obtain a second digital electrical signal.
The second calculating module 16 is connected to the second collecting module 15, and is configured to calculate an upper limit value of the primary frequency modulation capacity by combining the second digital electrical signal. Specifically, the second calculation module 16 includes: a first comparison module 16a, a second comparison module 16b, a third comparison module 16c, and a fourth comparison module 16 d. The first comparison module 16a is connected with the second acquisition module 15 and is used for comparing the difference value between the upper limit value of the loop thermal power and the second digital electric signal with 0 and taking the larger value as a first comparison result to output; the second comparing module 16b is configured to compare a difference between the turbine rated power and the turbine load set value with 0, and output a larger value of the difference as a second comparison result. The third comparing module 16c is connected to the first comparing module 16a and the second comparing module 16b, and configured to compare the first comparing result, the second comparing result, and the maximum value of the primary frequency modulation capacity, and output a smaller value as a third comparing result; the fourth comparing module 16d is connected to the third comparing module 16c, and is configured to compare the third comparison result with 0, and output a smaller value of the third comparison result as the upper limit value of the primary frequency modulation capacity. Wherein, the maximum value of the primary frequency modulation capacity is 5 percent of the rated power of the steam turbine set, namely 54.3 MWe.
The second output module 17 is connected to the second calculating module 16, and is configured to convert the primary frequency modulation capacity upper limit value into a third analog electrical signal. The main valve solenoid valve 18 is connected to the second output module 17, and is configured to adjust the opening of the main valve of the turbine under the control of the third analog electrical signal.
Specifically, in the present embodiment, the overall control of the CPR1000 unit is realized by an NC-DCS (non-safety-level plant digital control system), and the control and protection of the turbine generators are performed by a single system, which is called a TCS system (turbine control system). In order to realize the system conveniently, in the embodiment, a loop thermal power signal is collected through an analog quantity input acquisition card of an NC-DCS and is sent to a TCS through a 4-20 mA signal, a final signal is sent to a main steam valve of a steam turbine to be controlled through logic calculation of the TCS, a temperature signal collected on site is sent to a CPU of the NC-DCS through the 4-20 mA signal, a loop thermal power value is obtained through calculation, the thermal power value is sent to the analog quantity input acquisition card of the TCS through an analog quantity output clamping piece of an NC-DCS site control station, the CPU of the TCS calculates after receiving the signal and outputs a calculation result to a main steam valve electromagnetic valve 18 of the steam turbine through the analog quantity output clamping piece, and therefore the opening degree of the main steam valve of the steam turbine is controlled.
Therefore, in the present embodiment, the first acquisition module 11, the first calculation module 12, the signal transmission module 13, and the first output module 14 are all disposed in a non-safety-level digital instrument control system of a whole plant of a nuclear power plant, where the first acquisition module 11 is an analog input acquisition card of an NC-DCS, the first calculation module 12 is a CPU of the NC-DCS, and the signal transmission module 13 is a channel established between two field control stations. The first output module 14 is an analog output card of the NC-DCS. The second acquisition module 15, the second calculation module 16 and the second output module 17 are all arranged in a steam turbine control system of the nuclear power station, wherein the second acquisition module 15 is an analog input acquisition card, the second calculation module 16 is a CPU, and the first output module 14 is an analog output card. The first analog electric signal and the second analog electric signal are currents with numerical ranges of 4-20 mA.
it should be noted that, the loop thermal power has already been calculated by a mature method in the NC-DCS, and the signal may be directly referred to in this embodiment. The loop heat power value needs to be transmitted by two field control stations in the transmission of the NC-DCS, and the transmission process is executed by the existing communication network and communication mode of the NC-DCS. The two field control stations need to carry out channel configuration when carrying out signal transmission, and the attention is paid to checking whether the signal attribute configuration is correct, so that the communication failure is avoided. And (4) checking whether the card clamping precision of the NC-DCS and the TCS is matched with the thermal power precision requirement of a loop, and whether the loads of the NC-DCS field control station and the TCS control cabinet meet the requirement.
Based on the same inventive concept, the invention also provides a primary frequency modulation method for the steam turbine set of the nuclear power station, and fig. 6 is a flow chart of the primary frequency modulation method for the steam turbine set of the nuclear power station according to an embodiment of the invention, which comprises steps S1-S8.
In step S1, the temperature information of the primary loop of the nuclear power plant is converted into a first analog electrical signal.
In step S2, a first analog electrical signal is acquired and analog-to-digital converted to obtain a first digital electrical signal.
In step S3, a thermal power value of the nuclear power plant loop is calculated from the first digital electrical signal.
in step S4, the thermal power value is converted into a second analog electrical signal for output.
In step S5, a second analog electrical signal is acquired and analog-to-digital converted to obtain a second digital electrical signal.
In step S6, a primary modulation capacity upper limit value is calculated in combination with the second digital electric signal. Specifically, the process includes: comparing the difference value between the upper limit value of the loop thermal power and the second digital electric signal with 0, and taking the larger value as a first comparison result to output; comparing the difference value between the rated power of the steam turbine and the set value of the load of the steam turbine with 0, and taking the larger value as a second comparison result to output; comparing the first comparison result, the second comparison result and the maximum value of the primary frequency modulation capacity, and taking the smaller value as a third comparison result to output; and comparing the third comparison result with the value of 0, and taking the smaller value as the upper limit value of the primary frequency modulation capacity to output. Wherein, the maximum value of the primary frequency modulation capacity is 5 percent of the rated power of the steam turbine set, namely 54.3 MWe.
In step S7, the primary frequency modulation capacity upper limit value is converted into a third analog electrical signal.
In step S8, the opening degree of the main valve of the turbine is adjusted under the control of the third analog electric signal.
the first analog electric signal and the second analog electric signal are currents with numerical ranges of 4-20 mA.
in summary, according to the primary frequency modulation system and method for the steam turbine set of the nuclear power plant of the embodiment, in summer, the efficiency of the steam turbine is reduced due to the rising of the temperature of the seawater, and after the two loops reach the full power, even if the temperature of the two loops does not reach 1086MWe, a primary frequency modulation up-modulation space still exists, the primary frequency modulation up-modulation space will respond according to the thermal power condition of the current loop of the unit, if the thermal power of the loop reaches 2905MWe, the primary frequency modulation up-modulation is not continued, the thermal power of the loop is not exceeded the limit value, and the potential nuclear safety risk caused by the fact that the unit still responds to the primary frequency modulation of the.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
these computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (10)
1. A nuclear power station steam turbine unit primary frequency modulation system is characterized by comprising:
the temperature sensor is connected in a loop of the nuclear power station and used for converting temperature information of the loop of the nuclear power station into a first analog electric signal;
The first acquisition module is connected with the temperature sensor and used for acquiring the first analog electric signal and performing analog-to-digital conversion to obtain a first digital electric signal;
The first calculation module is connected with the first acquisition module and used for calculating the heat power value of the loop of the nuclear power station according to the first digital electric signal;
The signal transmission module is connected with the first calculation module and is used for transmitting the thermal power value;
The first output module is connected with the signal transmission module and used for converting the thermal power value into a second analog electric signal to be output;
The second acquisition module is connected with the first output module and used for acquiring the second analog electric signal and performing analog-to-digital conversion to obtain a second digital electric signal;
The second calculation module is connected with the second acquisition module and used for calculating the upper limit value of the primary frequency modulation capacity by combining the second digital electric signal;
The second output module is connected with the second calculation module and used for converting the primary frequency modulation capacity upper limit value into a third analog electric signal; and
and the main valve electromagnetic valve is connected with the second output module and used for adjusting the opening of a main valve of the steam turbine under the control of the third analog electric signal.
2. the nuclear power plant steam turbine unit primary frequency modulation system of claim 1, wherein the second calculation module comprises:
The first comparison module is connected with the second acquisition module and used for comparing the difference value between the upper limit value of the loop thermal power and the second digital electric signal with 0 and outputting a larger value serving as a first comparison result;
the second comparison module is used for comparing the difference value between the rated power of the steam turbine and the set value of the load of the steam turbine with 0, and taking the larger value as a second comparison result to output;
The third comparison module is connected with the first comparison module and the second comparison module and used for comparing the first comparison result, the second comparison result and the maximum value of the primary frequency modulation capacity, and taking the smaller value as a third comparison result to output;
And the fourth comparison module is connected with the third comparison module and used for comparing the third comparison result with 0, and taking the smaller value as the upper limit value of the primary frequency modulation capacity to output.
3. The nuclear power plant steam turbine unit primary frequency modulation system of claim 2, wherein the primary frequency modulation capacity maximum is 5% of the rated power of the steam turbine unit.
4. the primary frequency modulation system of a steam turbine set in a nuclear power plant as claimed in claim 1, wherein the first collection module, the first calculation module, the signal transmission module and the first output module are all disposed in a non-safety digital instrument control system of a whole plant of a nuclear power plant, wherein the first collection module is an analog input acquisition card, the first calculation module is a CPU, the signal transmission module is a signal transmission channel between two field control stations, and the first output module is an analog output card.
5. the system according to claim 1, wherein the second collection module, the second calculation module and the second output module are all disposed in a turbine control system of the nuclear power plant, wherein the second collection module is an analog input collection card, the second calculation module is a CPU, and the first output module is an analog output card.
6. The nuclear power plant steam turbine unit primary frequency modulation system as claimed in claim 1, wherein the first analog electrical signal and the second analog electrical signal are currents having a value range of 4 to 20 mA.
7. A primary frequency modulation method for a steam turbine set of a nuclear power station is characterized by comprising the following steps:
Converting the temperature information of the loop of the nuclear power station into a first analog electric signal;
Collecting the first analog electric signal, and performing analog-to-digital conversion to obtain a first digital electric signal;
Calculating the thermal power value of the loop of the nuclear power plant according to the first digital electric signal;
Converting the thermal power value into a second analog electric signal to be output;
Collecting the second analog electric signal, and performing analog-to-digital conversion to obtain a second digital electric signal;
Calculating the upper limit value of the primary frequency modulation capacity by combining the second digital electric signal;
Converting the primary frequency modulation capacity upper limit value into a third analog electric signal; and
And adjusting the opening degree of a main valve of the steam turbine under the control of the third analog electric signal.
8. The nuclear power plant steam turbine unit primary frequency modulation method of claim 7, wherein the calculating a primary frequency modulation capacity upper limit value in combination with the second digital electrical signal comprises:
Comparing the difference value between the upper limit value of the loop thermal power and the second digital electric signal with 0, and taking the larger value as a first comparison result to output;
Comparing the difference value between the rated power of the steam turbine and the set value of the load of the steam turbine with 0, and taking the larger value as a second comparison result to output;
comparing the first comparison result, the second comparison result and the maximum value of the primary frequency modulation capacity, and taking the smaller value as a third comparison result to output;
And comparing the third comparison result with 0, and taking the smaller value as the upper limit value of the primary frequency modulation capacity to output.
9. the nuclear power plant steam turbine unit primary frequency modulation method of claim 8, wherein the primary frequency modulation capacity maximum is 5% of the rated power of the steam turbine unit.
10. The nuclear power plant steam turbine unit primary frequency modulation system according to claim 7, wherein the first analog electrical signal and the second analog electrical signal are currents having a value range of 4 to 20 mA.
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