CN108615121B - Thermoelectric load distribution method and system based on multi-factor influence - Google Patents
Thermoelectric load distribution method and system based on multi-factor influence Download PDFInfo
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Abstract
The invention discloses a thermoelectric load distribution method and a system based on multi-factor influence, comprising the following steps: calculating a heat consumption curve function of the unit; establishing a unit mathematical model; establishing a simulator based on the unit mathematical model to obtain a consumption difference curve function under each working condition; acquiring a complete consumption difference curve function set based on the consumption difference curve function under each working condition; and performing thermoelectric load distribution calculation based on the unit heat consumption curve function and the consumption difference curve function set. The method overcomes the limitation caused by the fact that a difference consumption correction curve given by a manufacturer is used for correction in the prior art, obtains a difference consumption curve function set in a mass data simulation mode, and finally achieves more accurate thermoelectric load distribution calculation.
Description
Technical Field
The invention relates to the technical field of heat supply and energy conservation, in particular to a thermoelectric load distribution method and system based on multi-factor influence.
Background
At present, most of cities adopt a centralized heating mode to realize resident heating, and how to consider energy-saving measures from production to transportation and from transportation to use is a current hot topic, and various published existing means exist to optimize heat energy distribution. Among them, the prior art includes:
(1) and obtaining the structure and the form of a relation curve of heat consumption values of the unit when different main steam flows of the unit and different electric loads and heat loads are distributed through the variable working condition theoretical calculation of the heat supply steam extraction unit. Since, without knowledge of the structure and form of the curve, experiments are required for determining the curve for each main steam flow, thermal load, electrical load and also back pressure, which can be obtained by a large number of combinations. The experimental times are reduced by using the determination of the form of the curve structure, a reasonable experimental scheme is designed, and a heat consumption value curve of the unit is obtained under the condition of as few experiments as possible.
(2) On the basis of the theoretical analysis, the structure and the form of a heat consumption rate curve of the unit are obtained, a reasonable experimental scheme is designed, field experiments are carried out, specific parameters of the curve are determined, and the heat consumption rate curve of the unit can be obtained.
(3) On the basis of obtaining the heat consumption rate curve of each unit, the distribution optimization of the heat load and the electric load among the heat supply steam extraction units can be developed. And determining the actual heat rate of the unit according to the curve by using the actual operation data of the unit, and accurately correcting the heat rate according to the related parameter change which has a large influence on the heat rate to obtain the accurate heat rate value of the unit.
The genetic algorithm simulates the biological evolution process of the nature, can quickly optimize and obtain the solution of the problem through operations such as copying, crossing, mutation and the like, is a mature method widely applied to solving various optimization problems, and at present, a lot of researches for carrying out load distribution optimization of the unit adopt the genetic algorithm. Based on a genetic algorithm, according to the given electric load and heat load of the whole power plant and the related consumption difference curve given by a unit design manufacturer, and a user can input optimized constraint conditions such as the electric load and the heat load of a certain unit are specified to be a certain fixed value, the distribution optimization algorithm of the electric load and the heat load among the heat supply and steam extraction units is developed by minimizing the heat consumption value of the whole power plant, so that the distribution optimization of the electric load and the heat load among the heat supply and steam extraction units can be realized, and the optimal electric load and heat load set value of each unit is output.
Problems existing in the prior scheme
When the actual heat rate of the unit is calculated, the difference loss correction curve given by the unit manufacturer is used for correction, but the difference loss correction curve has obvious limitation. Firstly, a loss difference correction curve is calculated based on rated working conditions, but the unit cannot be corrected only by using rated working condition parameters in the process of continuously variable load operation; the steam turbine is known as a strong nonlinear system, and can be corrected within a small range, but once some parameters of the unit are changed within a large range, the method has obvious errors.
Disclosure of Invention
Aiming at the technical problems, the technical scheme provided by the invention accurately corrects the heat consumption rate of the unit based on the priori knowledge and actual mass operation data, so that the accurate calculation of the heat consumption rate of the unit is realized, and finally, the more accurate thermoelectric load distribution calculation is realized.
In one aspect, the invention is implemented using the following method: a method of thermoelectric load distribution based on multi-factor impact, comprising:
calculating a heat consumption curve function of the unit;
establishing a unit mathematical model;
establishing a simulator based on the unit mathematical model to obtain a consumption difference curve function under each working condition;
acquiring a complete consumption difference curve function set based on the consumption difference curve function under each working condition;
and performing thermoelectric load distribution calculation based on the unit heat consumption curve function and the consumption difference curve function set.
Further, the establishing of the unit mathematical model includes: massive thermodynamic historical data of the unit are collected, and a unit data model is established based on the historical data.
The establishing of the unit mathematical model based on the historical data comprises the following steps: and establishing a mathematical model of each device of the unit, and splicing the mathematical models of the devices according to a basic thermodynamic cycle structure of the unit to form a complete unit data model.
Further, the establishing of the simulator based on the unit mathematical model to obtain the consumption difference curve function under each working condition includes:
selecting a preset parameter related to heat rate;
analyzing each preset parameter as a control variable of the simulator;
and solving a loss-difference curve function under each working condition based on a least square method.
Further, the calculating the distribution of the thermoelectric load based on the heat consumption curve function of the unit and the set of the difference consumption curve function comprises: and performing thermoelectric load distribution calculation by utilizing a genetic algorithm based on the unit heat consumption curve function and the consumption difference curve function set.
In another aspect, the invention may be implemented using the following system: a multi-factor impact based thermoelectric load distribution system comprising:
the unit heat consumption curve function generation module is used for calculating a unit heat consumption curve function;
the unit mathematical model establishing module is used for establishing a unit mathematical model;
the consumption difference curve function generating module is used for establishing a simulator based on the unit mathematical model and acquiring the consumption difference curve function under each working condition;
the consumption difference curve function set generating module is used for acquiring a complete consumption difference curve function set based on the consumption difference curve functions under various working conditions;
and the thermoelectric load distribution module is used for carrying out thermoelectric load distribution calculation based on the heat consumption curve function of the unit and the consumption difference curve function set.
Further, the unit mathematical model building module is specifically configured to: massive thermodynamic historical data of the unit are collected, and a unit data model is established based on the historical data.
The establishing of the unit mathematical model based on the historical data comprises the following steps: and establishing a mathematical model of each device of the unit, and splicing the mathematical models of the devices according to a basic thermodynamic cycle structure of the unit to form a complete unit data model.
Further, the difference curve function generating module is specifically configured to:
selecting a preset parameter related to heat rate;
analyzing each preset parameter as a control variable of the simulator;
and solving a loss-difference curve function under each working condition based on a least square method.
Further, the thermoelectric load distribution module is specifically configured to: and performing thermoelectric load distribution calculation by utilizing a genetic algorithm based on the unit heat consumption curve function and the consumption difference curve function set.
In summary, the invention provides a thermoelectric load distribution method and system based on multi-factor influence, which is characterized in that a simulation machine is established by establishing a set accurate mathematical model and selecting a preset parameter related to heat rate as a control variable of the simulation machine, so as to finally obtain a consumption difference curve function, and the calculation of thermoelectric load distribution is finally realized by utilizing the set heat consumption curve function and the established consumption difference curve function set. Compared with the prior art, the method and the device have the advantages that the consumption difference correction curve provided by a manufacturer is abandoned to correct the actual operation heat consumption rate of the unit to a certain degree, and the heat consumption rate of the unit is finally corrected accurately by using massive thermodynamic historical data. Therefore, errors possibly brought by the traditional technical scheme are overcome, and the distribution of the thermoelectric load can be more accurately realized.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a flow chart of an embodiment of a method for multi-factor impact based thermoelectric load distribution according to the present invention;
FIG. 2 is a schematic diagram of a basic model of the regenerative surface heat exchanger according to the present invention;
FIG. 3 is a flow chart of a method for calculating the water temperature at the inlet of the regenerator in accordance with the present invention;
FIG. 4 is a block diagram of an embodiment of a multi-factor impact based thermoelectric load distribution system according to the present invention.
Detailed Description
In order to make the technical solutions in the embodiments of the present invention better understood and make the above objects, features, and advantages of the present invention more apparent and understandable, the following describes the technical solutions in the present invention in detail with reference to the accompanying drawings:
as shown in fig. 1, an embodiment of a thermoelectric load distribution method based on multi-factor influence provided by the present invention includes:
s101: calculating a heat consumption curve function of the unit; the method specifically comprises the following steps: and obtaining the structure and the form of a relation curve of the heat consumption values of the unit when different main steam flows of the unit and different electric loads and heat load distribution are obtained through the variable working condition theoretical calculation of the heat supply steam extraction unit, and further obtaining a heat consumption curve function of the unit.
S102: establishing a unit mathematical model; wherein, include: the method comprises the steps of collecting massive thermodynamic historical data of the unit, establishing a mathematical model of each device of the unit based on the historical data, and splicing the mathematical models of the devices according to a basic thermodynamic cycle structure of the unit to form a complete unit data model.
Wherein the massive thermodynamic historical data comprises: the method comprises the steps of establishing an accurate mathematical model for a unit by utilizing thermodynamic data, wherein the thermodynamic data comprises thermodynamic data related to the unit under each typical working condition of the unit (each typical working condition comprises 50%, 60%, 70%, 80%, 90% and 100% of thermodynamic data related to the unit under rated load), and fully considering nonlinear characteristics and dynamic characteristics of the model in the establishment process.
Firstly, acquiring related thermodynamic data of a unit, namely all parameters of each temperature, pressure and flow rate point, identifying related performance parameters through a model identification method based on theoretical knowledge of the characteristics of a through-flow part of a steam turbine, the characteristics of a surface type heat regenerator, the characteristics of a deaerator, the characteristics of a water feeding pump and the like, and establishing an accurate mathematical model of the equipment; and the following models (the stage group through-flow part, the heat regenerator and the water feed pump) of each part are spliced according to the basic thermodynamic cycle structure of the thermodynamic unit to form a complete thermodynamic balance calculation model of the steam turbine.
The mathematical model building process of each device of the unit is as follows:
1. level group model
The expansion process line in the actual turbine stage group is a smooth curve, and for a high-power turbine, the multistage extraction can be regarded as dividing the whole turbine into a plurality of different stage groups, so that the smooth thermodynamic expansion process curve of the whole turbine can be divided into a plurality of sections according to the stage groups, and each section of the process line can be regarded as a straight line approximately. Through verification, calculated values of all levels of steam state parameters in the stage group obtained by performing linear treatment on the thermodynamic expansion process line of a single stage group can meet the requirement of engineering application precision.
In the steam turbine, when the structure size of the through flow part is not changed, the steam parameters before and after a stage group (any plurality of series stages with approximately equal steam flow rate) have the following relation with the flow rate:
the temperature correction term in the above equation, which is generally approximately equal to 1, may not be considered, except in some special cases (e.g., where the initial or reheat temperature changes). For steam condensing units, the pressure ratio P1/P2 is usually negligibly small, if discussed in terms of the stage groups between the extraction sections, and therefore the above equation has the following simplified form:
wherein G is KP, namely keeping the simplified formula of Gere. In a steam turbine thermodynamic system, we assume that the coefficient K of the fleshy guerre equation for each stage is constant.
The turbine stages can be divided into regulated stages and non-regulated stages depending on whether the stage flow area varies with the load. In the case of a multistage steam turbine, which is the first working stage of the steam turbine, the flow area of the first working stage can be changed with the load change due to partial intake air, so that the regulation effect is achieved, and therefore the multistage steam turbine is called as a regulation stage.
Generally, the efficiency of the adjusting stage is lower than that of the middle stage, and the lower efficiency stage is adopted because variable working conditions need to be considered for air inlet of the high-pressure cylinder, main steam flow is different under different loads, and the adjusting stage is required to adjust, so that the efficiency of the whole turbine thermodynamic system and the safety and stability of the work of each middle stage are ensured.
(1) The adjusting stage efficiency is changed greatly along with the change of the main steam flow, and an adjusting stage efficiency curve is adopted for fitting in the calculation so as to achieve the purpose of reducing errors.
(2) In comparison with other non-design conditions, it can be found that the turbine stage group efficiency under other conditions can be regarded as a fixed value except that the winter heating period condition and the minimum steam extraction condition (i.e. the conditions of industrial steam extraction and heating steam extraction) need to be considered separately.
2. Water supply pump model
In a steam turbine thermodynamic system, a deaerator feed pump is an important part for raising boiler circulating water from deaerator saturation pressure to boiler feed pressure.
The following relationship can be known from the physical characteristics of the feed pump:
wherein: g-volume flow of water through the feed pump;
h-water pump head;
eta-working efficiency of the feed pump;
gs-mass flow of water through the feed pump;
hout-outlet water enthalpy value of the feed pump;
hin-enthalpy of inlet water of the feed pump;
3. regenerator model building
Fig. 2 is a schematic diagram showing a basic model of a regenerative surface heat exchanger.
The basic model is established as follows:
when a regenerator outlet temperature Tout is given, there is the following temperature-pressure relationship.
TRegenerative heat＝Tout+TDifference of upper end
The saturated pressure of the regenerator, pwreg, at this temperature is calculated, assuming the saturated state of the regenerator.
When pwre is known, there is the following relationship:
Pregenerative heat＝Ps×(1-Ks)
Wherein KS is the pressure loss coefficient of the steam extraction pipeline.
The average steam extraction pipeline pressure loss coefficient operation obtained through calculation can obtain the steam extraction point pressure of a stage group, the stage rear flow of the stage can be obtained by using a Foucault simplified formula G (KP), and the current stage steam extraction amount GS can be obtained by subtracting the stage front flow, namely:
Gs＝K0P0-K1P1
meanwhile, the enthalpy value of the main steam after the stage can be obtained by the enthalpy value and the stage efficiency obtained by the temperature and the pressure of the main steam before the stage, the pressure of the main steam after the stage is obtained by the pressure of the steam extraction point, and the temperature TS of the steam extraction point can be obtained by utilizing a Matlab program.
The following balance can be obtained by utilizing the heat balance relationship between the heat release of the main steam extraction and the heat absorption of the boiler water supply:
Gs×Hs+Gupper stage drainage×HUpper stage drainage-GHydrophobic×HHydrophobic＝G×(Hout-Hin)
Wherein Hs＝f(Ps，Ts)；
HUpper stage drainage＝f(PUpper stage heat regeneration，TUpper stage drainage)
HHydrophobic＝f(PRegenerative heat，THydrophobic)
GHydrophobic＝GUpper stage drainage+Gs
Hout＝f(PFeed water，Tout)
Hin＝f(PFeed water，Tin)
In the balance formula, only two unknown parameters Tin and T are hydrophobic, and the two parameters are known by the relationship of the difference of the lower ends of the surface type heat regenerator:
Thydrophobic＝Tin+TLower end difference
Through iterative calculation, a solution satisfying two balanced parameters can be obtained, so that the water temperature at the inlet of the heat regenerator is obtained, and the specific operation flow is shown in fig. 3.
In the process of establishing the model, the concept of a level control body is introduced. The stage control body is a control body which comprises a certain stage heater and comprises a part of boiler water supply or condensation water pipeline, a steam extraction pipeline and a part of drainage pipeline which are connected with the stage heater. In the process of establishing the model, the stage control body is used as a unit control body to be programmed, and the modularized stage group units are connected in series, so that a general thermodynamic system model of the steam turbine unit is formed.
S103: and establishing a simulator based on the unit mathematical model to obtain a consumption difference curve function under each working condition.
Specifically, the method includes but is not limited to: based on the unit mathematical model established in S102, the unit is accurately simulated, and the simulation is performed under each typical working condition to determine a power consumption difference curve function that fully considers the influence of each factor, where the power consumption difference curve function is a function of a difference value (Δ) between an electrical load (P), a thermal load (G), main parameters (unit thermodynamic parameters with strong correlation with the unit heat consumption rate, including main steam pressure, temperature, reheater outlet temperature, back pressure, superheater attemperation water volume, and reheater attemperation water volume) and a reference operation value (an operation reference value, also called an operation response value, which is the most economical or reasonable value of each operation parameter under a certain load working condition).
Preferably, the establishing a simulator based on the unit mathematical model to obtain the consumption difference curve function under each working condition includes:
selecting a preset parameter related to heat rate;
analyzing each preset parameter as a control variable of the simulator;
and solving a loss-difference curve function under each working condition based on a least square method.
Specifically, the method includes but is not limited to: selecting several preset parameters related to heat rate, including: main steam pressure, main steam temperature, reheat steam pressure, reheat steam temperature, backpressure, and the like. And performing control variable simulation analysis on the parameters, namely independently adjusting the main steam pressure while keeping other parameters unchanged, analyzing the change of the heat consumption rate of the unit under the condition of various parameter changes according to simulation data, and further solving a corresponding consumption difference curve function based on a least square method.
Taking the main steam temperature as an example, when simulation is carried out, a reference operation value is selected to be +/-10 ℃ (interval of 1 ℃) for simulation, simulation is carried out under the working conditions of determining each load point and determining the steam extraction amount, the heat consumption value of the unit under any main steam temperature under the working conditions is obtained through calculation according to obtained data, difference is obtained through comparison with the reference heat consumption curve function of the unit, finally, the heat consumption rate change value caused by the main steam temperature under each working condition is obtained, and the consumption difference curve function related to the main steam temperature is obtained through least square fitting.
S104: acquiring a complete consumption difference curve function set based on the consumption difference curve function under each working condition;
specifically, the method includes but is not limited to: and forming a consumption difference curve function set by using the consumption difference curve functions under various working conditions, and performing interpolation calculation by using the electric load, the heat load, the main parameters and the reference operation difference value of the unit in the actual consumption difference calculation process to obtain accurate consumption difference so as to correct the heat consumption rate.
S105: and performing thermoelectric load distribution calculation based on the unit heat consumption curve function and the consumption difference curve function set.
Specifically, the method includes but is not limited to: and calculating according to the obtained heat consumption curve function and the energy consumption difference curve function set of the unit, and performing final thermoelectric load distribution calculation based on a genetic algorithm.
As shown in fig. 4, an embodiment of a thermoelectric load distribution system based on multi-factor influence provided by the present invention comprises:
a unit heat consumption curve function generating module 401, configured to calculate a unit heat consumption curve function;
a unit mathematical model establishing module 402, configured to establish a unit mathematical model;
a consumption difference curve function generating module 403, configured to establish a simulator based on the unit mathematical model, and obtain a consumption difference curve function under each working condition;
a difference consumption curve function set generating module 404, configured to obtain a complete difference consumption curve function set based on the difference consumption curve function under each operating condition;
and the thermoelectric load distribution module 405 is configured to perform thermoelectric load distribution calculation based on the unit heat consumption curve function and the consumption difference curve function set.
Preferably, the unit mathematical model building module is specifically configured to: massive thermodynamic historical data of the unit are collected, and a unit data model is established based on the historical data.
The establishing of the unit mathematical model based on the historical data comprises the following steps: and establishing a mathematical model of each device of the unit, and splicing the mathematical models of the devices according to a basic thermodynamic cycle structure of the unit to form a complete unit data model.
Preferably, the consumption difference curve function generating module is specifically configured to:
selecting a preset parameter related to heat rate;
analyzing each preset parameter as a control variable of the simulator;
and solving a loss-difference curve function under each working condition based on a least square method.
Preferably, the thermoelectric load distribution module is specifically configured to: and performing thermoelectric load distribution calculation by utilizing a genetic algorithm based on the unit heat consumption curve function and the consumption difference curve function set.
The embodiments in the present specification are described in a progressive manner, and the same or similar parts in the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
As described above, the embodiments described above provide a thermoelectric load distribution method and system embodiment based on multi-factor influence, and consider the non-linear change in consumption difference caused by large-range variable working conditions of a steam-condensing unit with steam extraction and a back-pressure unit with steam extraction when performing combined thermoelectric load distribution. The invention abandons the correction by using the loss correction curve provided by manufacturers, but obtains a unit mathematical model by using massive thermodynamic data, and further obtains the loss curve function under each working condition. And finally, the electric load and the heat load after the optimization of the computer set are more accurately calculated by using the correction method. The embodiment fully considers the influence of various factors in the thermoelectric load distribution calculation process, simultaneously considers the nonlinear characteristics of the unit, can bring more accurate and detailed calculation results for the implementation unit, finally realizes more accurate calculation compared with the original method, and further realizes obvious energy-saving effect.
The above examples are intended to illustrate but not to limit the technical solutions of the present invention. Any modification or partial replacement without departing from the spirit and scope of the present invention should be covered in the claims of the present invention.
Claims (2)
1. A method for multi-factor impact based thermoelectric load distribution, comprising:
s101: calculating a heat consumption curve function of the unit;
obtaining the structure and the form of a relation curve of heat consumption values of the unit when different main steam flows of the unit and different electric loads and heat load distribution are obtained through the theoretical calculation of variable working conditions of the heat supply steam extraction unit, and further obtaining a heat consumption curve function of the unit;
s102: establishing a unit mathematical model;
the method comprises the steps of establishing a mathematical model of each device of the unit by collecting massive thermodynamic historical data of the unit based on the historical data, and splicing the mathematical models of the devices according to a basic thermodynamic cycle structure of the unit to form a complete unit data model;
wherein the mass thermodynamic history data comprises: the system comprises a main steam pressure, a main steam temperature, a reheater inlet pressure, a reheater inlet temperature, each steam extraction point pressure, each reheater outlet water temperature, an inlet water temperature, a drain temperature, each reheater shell side pressure, a pipe side pressure, and a boiler final feed water temperature and pressure;
the mathematical model building process of each device of the unit is as follows:
(1) class group model
For a high-power steam turbine, the multistage extraction is regarded as dividing the whole turbine into a plurality of different stage groups, the smooth thermodynamic expansion process curve of the whole turbine is divided into a plurality of sections according to the stage groups, each section of thermodynamic expansion process line can be regarded as a straight line approximately, and the calculated value of each stage of steam state parameter in the stage group obtained by performing straight line processing on the thermodynamic expansion process line of a single stage group can meet the requirement of engineering application precision;
in the steam turbine, when the structure size of the through-flow part is not changed, the steam parameters before and after the stage group have the following relation with the flow rate:
to the condenser unit, its pressure ratio P1/P2Usually very small and negligible, the above equation is simplified:
wherein G is KP, namely a Foster simplified formula, and in a turbine thermodynamic system, K is a coefficient constant of the Foster formula;
(2) water supply pump model
In a steam turbine thermodynamic system, a deaerator feed water pump is used for raising boiler circulating water from deaerator saturation pressure to boiler feed water pressure, and the following relationship can be known according to the physical characteristics of the feed water pump:
wherein: g-volume flow of water through the feed pump;
h-water pump head;
eta-working efficiency of the feed pump;
GS-mass flow of water through the feed pump;
Hout-feed pump outlet water enthalpy;
Hin-feed pump inlet water enthalpy;
(3) regenerator model building
The establishment process of the surface type regenerative heat exchanger is as follows:
when the temperature T of the water outlet of the heat regenerator is givenoutWhen, the following temperature and pressure relationship is given:
Tregenerative heat＝Tout+TDifference of upper end
The saturation pressure P of the regenerator at the temperature is obtained by calculation according to the assumption of the saturation state of the regeneratorRegenerative heat，
When P is presentRegenerative heatWhen known, there is the following relationship:
Pregenerative heat＝Ps×(1-Ks)
Wherein, KsThe coefficient of pressure loss of the steam extraction pipeline is;
the average steam extraction pipeline pressure loss coefficient obtained through calculation can be used for calculating the steam extraction point pressure of a stage group, the stage rear flow of the stage can be obtained by using a Friedel's simplified formula G (KP), and the stage front flow is subtracted to obtain the stage steam extraction amount GsNamely:
Gs＝K0P0-K1P1
meanwhile, the enthalpy value and the stage efficiency of the main steam after the stage are obtained by the enthalpy value and the stage efficiency obtained by the temperature and the pressure of the main steam before the stage, the pressure of the main steam after the stage is obtained by the pressure of the steam extraction point, and the temperature T of the steam extraction point is obtained by using a Matlab programs；
The following balance can be obtained by utilizing the heat balance relationship between the heat release of the main steam extraction and the heat absorption of the boiler water supply:
Gs×Hs+Gupper stage drainage×HUpper stage drainage-GHydrophobic×HHydrophobic＝G×(Hout-Hin)
Wherein Hs＝f(Ps，Ts)；
HUpper stage drainage＝f(PUpper stage heat regeneration，TUpper stage drainage)
HHydrophobic＝f(PRegenerative heat，THydrophobic)
GHydrophobic＝GUpper stage drainage+Gs
Hout＝f(PFeed water，Tout)
Hin＝f(PFeed water，Tin)
With only two unknown parameters T in the balanceinAnd THydrophobicThe two parameters can be known from the relationship of the lower end difference of the surface type heat regenerator:
Thydrophobic＝Tin+TLower end difference
Solving the solution of two parameters meeting the balance type through iterative calculation, thereby solving the water temperature at the inlet of the heat regenerator;
s103: establishing a simulator based on the unit mathematical model to obtain a consumption difference curve function under each working condition;
accurately simulating the unit based on the unit mathematical model established in the S102, and simulating under various typical working conditions to determine a difference consumption curve function which fully considers the main steam pressure, the main steam temperature, the reheat steam pressure, the reheat steam temperature and the backpressure parameter, wherein the difference consumption curve function is a function of the electric load P, the heat load G and the difference value between the main parameter and the reference operation value;
s104: acquiring a complete consumption difference curve function set based on the consumption difference curve function under each working condition;
forming a consumption difference curve function set by using consumption difference curve functions under various working conditions, and performing interpolation calculation by using the electric load, the heat load, the main parameters and the reference operation difference value of the unit in the actual consumption difference calculation process to obtain accurate consumption difference so as to correct the heat consumption rate;
s105: performing thermoelectric load distribution calculation based on the unit heat consumption curve function and the consumption difference curve function set;
and calculating according to the obtained heat consumption curve function and the energy consumption difference curve function set of the unit, and performing final thermoelectric load distribution calculation based on a genetic algorithm.
2. A multi-factor impact based thermoelectric load distribution system, comprising:
the unit heat consumption curve function generation module is used for calculating a unit heat consumption curve function; obtaining the structure and the form of a relation curve of heat consumption values of the unit when different main steam flows of the unit and different electric loads and heat load distribution are obtained through the theoretical calculation of variable working conditions of the heat supply steam extraction unit, and further obtaining a heat consumption curve function of the unit;
the unit mathematical model establishing module is used for establishing a unit mathematical model; the method comprises the steps of establishing a mathematical model of each device of the unit by collecting massive thermodynamic historical data of the unit based on the historical data, and splicing the mathematical models of the devices according to a basic thermodynamic cycle structure of the unit to form a complete unit data model;
wherein the mass thermodynamic history data comprises: the system comprises a main steam pressure, a main steam temperature, a reheater inlet pressure, a reheater inlet temperature, each steam extraction point pressure, each reheater outlet water temperature, an inlet water temperature, a drain temperature, each reheater shell side pressure, a pipe side pressure, and a boiler final feed water temperature and pressure;
the mathematical model building process of each device of the unit is as follows:
(1) class group model
For a high-power steam turbine, the multistage extraction is regarded as dividing the whole turbine into a plurality of different stage groups, the smooth thermodynamic expansion process curve of the whole turbine is divided into a plurality of sections according to the stage groups, each section of thermodynamic expansion process line can be regarded as a straight line approximately, and the calculated value of each stage of steam state parameter in the stage group obtained by performing straight line processing on the thermodynamic expansion process line of a single stage group can meet the requirement of engineering application precision;
in the steam turbine, when the structure size of the through-flow part is not changed, the steam parameters before and after the stage group have the following relation with the flow rate:
to the condenser unit, its pressure ratio P1/P2Usually very small and negligible, the above equation is simplified:
wherein G is KP, namely a Foster simplified formula, and in a turbine thermodynamic system, K is a coefficient constant of the Foster formula;
(2) water supply pump model
In a steam turbine thermodynamic system, a deaerator feed water pump is used for raising boiler circulating water from deaerator saturation pressure to boiler feed water pressure, and the following relationship can be known according to the physical characteristics of the feed water pump:
wherein: g-volume flow of water through the feed pump;
h-water pump head;
eta-working efficiency of the feed pump;
GS-mass flow of water through the feed pump;
Hout-feed pump outlet water enthalpy;
Hin-feed pump inlet water enthalpy;
(3) regenerator model building
The establishment process of the surface type regenerative heat exchanger is as follows:
when the temperature T of the water outlet of the heat regenerator is givenoutWhen, the following temperature and pressure relationship is given:
Tregenerative heat＝Tout+TDifference of upper end
The saturation pressure P of the regenerator at the temperature is obtained by calculation according to the assumption of the saturation state of the regeneratorRegenerative heat，
When P is presentRegenerative heatWhen known, there is the following relationship:
Pregenerative heat＝Ps×(1-Ks)
Wherein, KsThe coefficient of pressure loss of the steam extraction pipeline is;
the average steam extraction pipeline pressure loss coefficient obtained through calculation can be used for calculating the steam extraction point pressure of a stage group, the stage rear flow of the stage can be obtained by using a Friedel's simplified formula G (KP), and the stage front flow is subtracted to obtain the stage steam extraction amount GsNamely:
Gs＝K0P0-K1P1
meanwhile, the enthalpy value and the stage efficiency of the main steam after the stage are obtained by the enthalpy value and the stage efficiency obtained by the temperature and the pressure of the main steam before the stage, the pressure of the main steam after the stage is obtained by the pressure of the steam extraction point, and the temperature T of the steam extraction point is obtained by using a Matlab programs；
The following balance can be obtained by utilizing the heat balance relationship between the heat release of the main steam extraction and the heat absorption of the boiler water supply:
Gs×Hs+Gupper stage drainage×HUpper stage drainage-GHydrophobic×HHydrophobic＝G×(Hout-Hin)
Wherein Hs＝f(Ps，Ts)；
HUpper stage drainage＝f(PUpper stage heat regeneration，TUpper stage drainage)
HHydrophobic＝f(PRegenerative heat，THydrophobic)
GHydrophobic＝GUpper stage drainage+Gs
Hout＝f(PFeed water，Tout)
Hin＝f(PFeed water，Tin)
With only two unknown parameters T in the balanceinAnd THydrophobicThe two parameters can be known from the relationship of the lower end difference of the surface type heat regenerator:
Thydrophobic＝Tin+TLower end difference
Solving the solution of two parameters meeting the balance type through iterative calculation, thereby solving the water temperature at the inlet of the heat regenerator;
the consumption difference curve function generating module is used for establishing a simulator based on the unit mathematical model and acquiring the consumption difference curve function under each working condition; accurately simulating the unit based on a mathematical model of each device of the unit, and simulating under each typical working condition to determine a difference consumption curve function which fully considers main steam pressure, main steam temperature, reheat steam pressure, reheat steam temperature and backpressure parameters, wherein the difference consumption curve function is a function of an electric load P, a heat load G, and a difference value between a main parameter and a reference operation value;
the consumption difference curve function set generating module is used for acquiring a complete consumption difference curve function set based on the consumption difference curve functions under various working conditions; forming a consumption difference curve function set by using consumption difference curve functions under various working conditions, and performing interpolation calculation by using the electric load, the heat load, the main parameters and the reference operation difference value of the unit in the actual consumption difference calculation process to obtain accurate consumption difference so as to correct the heat consumption rate;
the thermoelectric load distribution module is used for carrying out thermoelectric load distribution calculation on the basis of the heat consumption curve function of the unit and the difference consumption curve function set; and calculating according to the obtained heat consumption curve function and the energy consumption difference curve function set of the unit, and performing final thermoelectric load distribution calculation based on a genetic algorithm.
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