1. An indirect steam distribution method of a steam inlet regulating valve is characterized by comprising the following steps:

acquiring a sequence valve backpressure correction function, a flow distribution function, an overlap correction function, a single valve flow correction function and a critical flow-opening function of the steam turbine according to test data of a first preset flow characteristic test and a second preset flow characteristic test which are performed in advance;

inputting the received target flow instruction into an indirect steam distribution function group formed by sequentially connecting the sequence valve backpressure correction function, the flow distribution function and the overlap correction function to obtain a first intermediate instruction; inputting the target flow instruction into the single valve flow correction function to obtain a second intermediate instruction;

and obtaining the opening instruction of the steam inlet regulating valve according to the operation control mode of the steam turbine, the first intermediate instruction, the second intermediate instruction and the critical flow-opening function.

2. The indirect steam distribution method of an inlet steam regulating valve according to claim 1, wherein the first preset flow characteristic test is a flow characteristic test performed under the condition that the overlap of the inlet steam regulating valve is removed from the operating state of the turbine sequence valve, and the second preset flow characteristic test is a flow characteristic test performed under the operating state of the turbine single valve;

the method for acquiring the sequence valve backpressure correction function, the flow distribution function, the overlap correction function, the single valve flow correction function and the critical flow-opening function of the steam turbine according to the test data of the first preset flow characteristic test and the second preset flow characteristic test which are performed in advance comprises the following steps:

acquiring first test data of each steam inlet regulating valve under a plurality of opening degrees in a first preset flow characteristic test; the first test data at least comprise a post-regulation-stage pressure, a post-regulation-stage temperature, a main steam pressure, a main steam temperature and the opening degree of each steam inlet regulating valve;

acquiring a sequence valve backpressure correction function, a flow distribution function and an overlap correction function of the steam turbine according to the first test data;

acquiring second test data of each steam inlet regulating valve under a plurality of opening degrees in a second preset flow characteristic test; the second test data at least comprise the pressure after the regulation stage, the temperature after the regulation stage, the main steam pressure, the main steam temperature and the opening degree of each steam inlet regulating valve;

and acquiring a single valve flow correction function and a critical flow-opening function of the steam turbine according to the second test data.

3. The indirect steam distribution method of an inlet steam regulating valve according to claim 2, wherein the obtaining a sequence valve back pressure correction function of the steam turbine based on the first test data comprises:

acquiring actual relative flow and corresponding total critical flow of each steam inlet regulating valve in an opening state according to the first test data;

generating a curve of the actual relative flow and the total critical flow according to the actual relative flow and the corresponding total critical flow of each steam inlet regulating valve in the opening state;

and determining a function of the curve of the actual relative flow and the total critical flow as the sequence valve back pressure correction function of the steam turbine.

4. The indirect steam distribution method for the steam inlet regulating valve according to claim 3, wherein the obtaining the flow distribution function of the steam turbine according to the first test data comprises:

according to the first test data, acquiring the total critical flow corresponding to each steam inlet regulating valve when the steam inlet regulating valve starts to be opened and the total critical flow corresponding to each steam inlet regulating valve when the steam inlet regulating valve is fully opened;

and acquiring the flow distribution function of the steam turbine according to the preset corresponding relation between the total critical flow corresponding to the starting time and the total critical flow corresponding to the full opening time.

5. The indirect steam distribution method for the steam inlet regulating valve according to claim 2, wherein the step of obtaining the overlap correction function of the steam turbine according to the first test data comprises the following steps:

according to the first test data, acquiring the back pressure of the partially opened steam inlet regulating valve and the front-back pressure ratio of the regulating valve;

determining the overlapping degree setting starting position and the overlapping degree setting ending position of two adjacent opened steam inlet regulating valves according to the valve back pressure of the partially opened steam inlet regulating valve and the front-to-back pressure ratio of the regulating valve;

and determining the overlap correction function of the steam turbine according to the overlap area condition of two adjacent opened steam inlet regulating valves.

6. The indirect steam distribution method of the steam inlet regulating valve according to claim 2, wherein the obtaining of the critical flow-opening function of the steam turbine according to the second test data comprises:

according to the second test data, obtaining critical flow of each steam inlet regulating valve in a stable state with different opening degrees;

generating a curve of critical flow and opening according to the critical flow of each steam inlet regulating valve in a stable state with different openings;

and determining a function of the curve of the critical flow and the opening as the critical flow-opening function of the steam turbine.

7. The indirect steam distribution method of an inlet steam regulating valve according to claim 2, wherein obtaining a single valve flow correction function of the steam turbine based on the second test data comprises:

acquiring actual relative flow and corresponding critical flow of each steam inlet regulating valve in a stable state with different opening degrees according to the second test data;

generating curves of actual relative flow and critical flow according to the actual relative flow and the corresponding critical flow of each steam inlet regulating valve in the stable state with different opening degrees;

and determining a function of the curves of the actual relative flow and the critical flow as the single valve flow correction function of the steam turbine.

8. The indirect steam distribution method of an inlet steam regulating valve according to any one of claims 1 to 7, wherein the obtaining of the opening degree command of the inlet steam regulating valve according to the operational control mode of the steam turbine, the first intermediate command, the second intermediate command and the critical flow-opening degree function comprises:

under the condition that the operation control mode of the steam turbine is a sequence valve regulation mode, inputting the first intermediate instruction into the critical flow-opening function to obtain an opening instruction of the steam inlet regulating valve;

and under the condition that the operation control mode of the steam turbine is a single-valve regulation mode, inputting the second intermediate instruction into the critical flow-opening function to obtain an opening instruction of the steam inlet regulating valve.

9. An indirect steam distribution device of a steam inlet regulating valve is characterized by comprising:

the function acquisition module is used for acquiring a sequence valve backpressure correction function, a flow distribution function, an overlap correction function, a single valve flow correction function and a critical flow-opening function of the steam turbine according to test data of a first preset flow characteristic test and a second preset flow characteristic test which are performed in advance; the first preset flow characteristic test is a flow characteristic test which is carried out under the condition that the overlap degree of the steam inlet regulating valve is removed in the working state of the steam turbine sequence valve, and the second preset flow characteristic test is a flow characteristic test which is carried out under the working state of a single valve of the steam turbine;

the input module is used for inputting the received target flow instruction into an indirect steam distribution function group formed by sequentially connecting the sequence valve backpressure correction function, the flow distribution function and the overlap correction function to obtain a first intermediate instruction; inputting the target flow instruction into the single valve flow correction function to obtain a second intermediate instruction;

and the instruction generating module is used for obtaining the opening instruction of the steam inlet regulating valve according to the operation control mode of the steam turbine, the first intermediate instruction, the second intermediate instruction and the critical flow-opening function.

10. A steam turbine comprising a memory, a processor and a computer program stored in said memory and executable on said processor, wherein said processor when executing said computer program performs the steps of the method according to any one of claims 1 to 8.

Background

The steam turbine is a rotating machine which takes steam as power and converts the heat energy of the steam into mechanical work, and is the most widely applied prime mover in modern thermal power plants. A Digital Electro-Hydraulic control system (DEH) of a steam turbine is an important component of a steam turbine generator set as an adjusting controller for starting, stopping, normal operation and accident conditions of the steam turbine.

The DEH can control the steam inlet flow of the steam turbine through the steam distribution function of each steam inlet regulating valve. For the steam turbine adopting the steam inlet regulating valve and the nozzle for steam distribution, the reasonably set steam distribution function is the basis for realizing the functions of unit power control, primary frequency modulation of a power grid and the like, and the accurate control of the steam inlet flow of the steam turbine under different control modes can be ensured.

At present, no uniform industry standard is available for the specification of the setting of the steam distribution function of the steam turbine. The steam distribution function can be set by adopting an indirect steam distribution mode, namely, the flow instruction of the steam turbine is converted into the valve position instruction of each steam inlet regulating valve through a plurality of intermediate conversion functions. However, the existing steam distribution function set in the indirect steam distribution mode is complicated to set and has fuzzy specific meaning, the control effect on the steam inlet flow of the steam turbine is poor, and a method for setting the indirect steam distribution of the steam inlet regulating valve for accurately controlling the steam turbine flow is urgently needed.

Disclosure of Invention

The embodiment of the invention provides an indirect steam distribution method and device of a steam inlet regulating valve and a steam turbine, and aims to solve the problem of poor steam inlet flow control effect of the steam turbine

In a first aspect, an embodiment of the present invention provides an indirect steam distribution method for a steam inlet regulating valve, including:

acquiring a sequence valve backpressure correction function, a flow distribution function, an overlap correction function, a single valve flow correction function and a critical flow-opening function of the steam turbine according to test data of a first preset flow characteristic test and a second preset flow characteristic test which are performed in advance; the method comprises the following steps that a first preset flow characteristic test is carried out under the condition that the overlap degree of a steam inlet regulating valve is removed in the working state of a steam turbine sequence valve, and a second preset flow characteristic test is carried out under the working state of a single valve of the steam turbine;

inputting the received target flow instruction into an indirect steam distribution function group formed by sequentially connecting a sequence valve backpressure correction function, a flow distribution function and an overlap correction function to obtain a first intermediate instruction; inputting the target flow instruction into a single valve flow correction function to obtain a second intermediate instruction;

and obtaining the opening instruction of the steam inlet regulating valve according to the operation control mode of the steam turbine, the first intermediate instruction, the second intermediate instruction and the critical flow-opening function.

In a second aspect, an embodiment of the present invention provides an indirect steam distribution device for a steam inlet regulating valve, including:

the function acquisition module is used for acquiring a sequence valve backpressure correction function, a flow distribution function, an overlap correction function, a single valve flow correction function and a critical flow-opening function of the steam turbine according to test data of a first preset flow characteristic test and a second preset flow characteristic test which are performed in advance; the method comprises the following steps that a first preset flow characteristic test is carried out under the condition that the overlap degree of a steam inlet regulating valve is removed in the working state of a steam turbine sequence valve, and a second preset flow characteristic test is carried out under the working state of a single valve of the steam turbine;

the input module is used for inputting the received target flow instruction into an indirect steam distribution function group formed by sequentially connecting a sequence valve backpressure correction function, a flow distribution function and an overlap correction function to obtain a first intermediate instruction; inputting the target flow instruction into a single valve flow correction function to obtain a second intermediate instruction;

and the instruction generating module is used for obtaining the opening instruction of the steam inlet regulating valve according to the operation control mode of the steam turbine, the first intermediate instruction, the second intermediate instruction and the critical flow-opening function.

In a third aspect, embodiments of the present invention provide a steam turbine, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method according to the first aspect.

Compared with the prior art, the embodiment of the invention has the following beneficial effects:

the embodiment of the invention provides an indirect steam distribution method and device for a steam inlet regulating valve and a steam turbine, which can obtain a sequence valve backpressure correction function, a flow distribution function, an overlap correction function, a single valve flow correction function and a critical flow-opening function of the steam turbine according to test data of a first preset flow characteristic test and a second preset flow characteristic test which are performed in advance. Then, the received target flow instruction may be input to an indirect steam distribution function group formed by sequentially connecting a sequence valve backpressure correction function, a flow distribution function, and an overlap correction function to obtain a first intermediate instruction, and the target flow instruction may be input to a single-valve flow correction function to obtain a second intermediate instruction. And finally, obtaining the opening instruction of the steam inlet regulating valve according to the operation control mode of the steam turbine, the first intermediate instruction, the second intermediate instruction and the critical flow-opening function.

Therefore, on the basis of field tests, theoretical calculation is combined, and through specific setting operation steps, the steam distribution function of the steam turbine in an indirect steam distribution mode can be measured and calculated, accurate quantitative data are provided for the steam turbine to optimize the steam distribution performance and the regulation performance of the steam turbine, accurate parameter setting can be provided for the optimization of the steam distribution and the regulation characteristics of the steam turbine, field implementation is facilitated, and the control effect of the steam inlet flow of the steam turbine is greatly improved.

In addition, the problems of specification setting and setting in the existing field are solved, and the flow of the steam turbine can be accurately controlled on the basis of field tests.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

FIG. 1 is a flow chart illustrating the steps of an indirect steam distribution method for an intake regulating valve according to an embodiment of the present invention;

FIG. 2 is a flow chart of a flow instruction process according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of an indirect steam distribution device of an inlet steam regulating valve according to an embodiment of the present invention;

FIG. 4 is a schematic illustration of a steam turbine provided in accordance with an embodiment of the present invention.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the following description is made by way of specific embodiments with reference to the accompanying drawings.

As described in the background art, the steam distribution function set in the existing indirect steam distribution mode has a poor control effect on the steam inlet flow of the steam turbine.

In addition, in the aspect of setting a steam turbine steam distribution function, a unified industry standard is not yet available for standardization, so that an indirect steam distribution method for a steam inlet regulating valve is urgently needed to solve the standardization and setting problems in the field at present.

In order to solve the problems in the prior art, the embodiment of the invention provides an indirect steam distribution method and device of a steam inlet regulating valve and a steam turbine. First, an indirect steam distribution method of the steam inlet regulating valve provided by the embodiment of the invention is described below.

As shown in fig. 1, an indirect steam distribution method for an intake regulating valve provided in an embodiment of the present invention may include the following steps:

step S110, acquiring a sequence valve backpressure correction function, a flow distribution function, an overlap correction function, a single valve flow correction function and a critical flow-opening function of the steam turbine according to test data of a first preset flow characteristic test and a second preset flow characteristic test which are performed in advance.

The first preset flow characteristic test is a flow characteristic test which is carried out under the condition that the overlap degree of the steam inlet regulating valve is removed in the working state of the steam turbine sequence valve, and the second preset flow characteristic test is a flow characteristic test which is carried out under the working state of a single valve of the steam turbine.

Optionally, the specific processing of step S110 may be as follows:

acquiring first test data of each steam inlet regulating valve under a plurality of opening degrees in a first preset flow characteristic test; the first test data at least comprises the pressure after the regulation stage, the temperature after the regulation stage, the main steam pressure, the main steam temperature and the opening degree of each steam inlet regulating valve;

acquiring a sequence valve backpressure correction function, a flow distribution function and an overlap correction function of the steam turbine according to the first test data;

acquiring second test data of each steam inlet regulating valve under a plurality of opening degrees in a second preset flow characteristic test; the second test data at least comprises the pressure after the regulation stage, the temperature after the regulation stage, the main steam pressure, the main steam temperature and the opening degree of each steam inlet regulating valve;

and acquiring a single valve flow correction function and a critical flow-opening function of the steam turbine according to the second test data.

In some embodiments, the first predetermined flow characteristic test may be performed as follows:

quitting the unit operation coordination control, quitting the primary frequency modulation and steam turbine remote control functions, and removing the overlapping degree of the steam inlet regulating valve in the working state of the steam turbine sequence valve;

under the conditions of the rated load and the rated main steam temperature of the unit, adjusting the main steam pressure of the steam turbine to fully open each steam inlet adjusting valve, recording the main steam pressure at the moment, and keeping the main steam pressure unchanged in the subsequent test process;

during the process of slowly reducing the total flow instruction of the steam turbine, each steam inlet regulating valve is gradually closed until the opening degree of the last two steam inlet regulating valves is adjusted to a certain opening degree, such as 30%.

And recording the load, the main steam pressure, the main steam temperature, the pressure after the regulation stage, the temperature after the regulation stage and the opening degree of each steam inlet regulating valve which are in a stable state under different opening degrees.

In some embodiments, the process of the second preset flow characteristic test may be as follows:

exiting the unit operation coordination control, exiting the primary frequency modulation and steam turbine remote control function, and entering a steam turbine single valve regulation mode;

under the conditions of the rated load and the rated main steam temperature of the unit, adjusting the main steam pressure of the steam turbine to fully open each steam inlet adjusting valve, recording the main steam pressure at the moment, and keeping the main steam pressure unchanged in the later test process;

and slowly reducing the total flow instruction of the steam turbine, and keeping synchronous closing of all the steam inlet regulating valves until the opening degree of all the regulating valves is finally adjusted to a certain opening degree, such as below 20%.

And recording main parameters of each steam inlet regulating valve in a stable state, wherein the main parameters comprise load, main steam pressure and temperature, regulating stage pressure and temperature, opening degree of each steam inlet regulating valve and the like.

Alternatively, the specific process of obtaining the sequence valve backpressure modification function of the steam turbine may be as follows: acquiring actual relative flow and corresponding total critical flow of each steam inlet regulating valve in an opening state according to the first test data; generating a curve of the actual relative flow and the total critical flow according to the actual relative flow and the corresponding total critical flow of each steam inlet regulating valve in the opening state; and determining a function of the curve of the actual relative flow and the total critical flow as a sequence valve back pressure correction function of the steam turbine.

In some embodiments, the actual relative flow at steady state of each inlet steam regulating valve can be calculated by equation (1), as follows:

wherein p is₂、υ₂、p_msThe unit of the pressure after the adjusting stage, the specific volume after the adjusting stage and the main steam pressure are respectively MPa, m3/kg and MPa, and the parameter with the lower corner mark of 0 is the rated load state parameter.

Then, the critical pressure ratio of the regulating stage and the total critical pressure ratio of the regulating stage of the steam inlet regulating valve under the condition that the overlap degree of the steam inlet regulating valve is removed from the working state of the sequence valve of the steam turbine can be calculated through the following steps:

i) calculating the front-back pressure ratio of the regulating stage in the working condition (fully-opened working condition of the steam inlet regulating valve) of each valve point of the working state of the sequence valve by using a formula (2):

wherein epsilon_nIndicating a regulated stage pressure ratio; p is a radical of₀Indicating the pre-conditioning pressure in MPa.

When the steam inlet regulating valve is fully opened under the working condition of the valve point, the front pressure of the regulating stage is the rear pressure of the steam inlet regulating valve, and the front pressure can be calculated by adopting a formula (3) to obtain:

wherein PL is the designed pressure drop in unit percent of the steam turbine steam inlet stop valve and the steam inlet regulating valve in the fully-opened state.

And ii) when the pressure ratio before and after the regulating stage of a certain valve point working condition is less than 0.5, taking the valve point working condition as a critical pressure ratio calculation reference working condition, and using a lower corner mark B to represent. Taking all the fully-opened working condition data of the steam inlet regulating valve, and calculating R characteristic value by using a lower corner mark 'VWO':

wherein p is₀、T₀Respectively, the pre-stage pressure and the pre-stage temperature of the adjustment stage are expressed in MPa and K.

Calculating the critical pressure ratio of the regulating stage using equation (4):

iv) calculating the total critical pressure ratio of the regulating stage of the steam inlet regulating valve by adopting a formula (5):

therefore, the total critical pressure ratio of the regulating stage of the steam inlet regulating valve can be obtained.

Then, after obtaining the total critical pressure ratio of the regulating stage of the steam inlet regulating valve, the total critical flow rate of each steam inlet regulating valve in the stable opening state can be calculated by using the following formula:

wherein epsilon_n(vb)Representing the total critical pressure ratio of the steam inlet regulating valve and the regulating stage,ε_nc(vb)representing the total critical pressure ratio Fr of the regulating stage of the steam inlet regulating valve_cThe total critical flow of each steam inlet regulating valve in a stable opening state is obtained.

And finally, drawing a flow instruction-total critical flow curve in the state of the sequence valve according to the actual relative flow and the corresponding total critical flow obtained by calculation under the opening state of each steam inlet regulating valve, wherein the function corresponding to the curve is a sequence valve backpressure correction function F (x1), and the flow instruction is the actual relative flow value obtained by the test.

Optionally, the specific process of obtaining the flow distribution function of the steam turbine may be as follows: according to the first test data, acquiring the total critical flow corresponding to each steam inlet regulating valve when the steam inlet regulating valve starts to be opened and the total critical flow corresponding to each steam inlet regulating valve when the steam inlet regulating valve is fully opened; and acquiring a flow distribution function of the steam turbine according to a preset corresponding relation between the total critical flow corresponding to the starting time and the total critical flow corresponding to the full starting time.

In some embodiments, the flow distribution function of the (i) th inlet modulation valve may be expressed as:

F_rfcCi)＝KX+B；

wherein, F_rfc(i)Is the critical flow instruction percentage of the (i) th steam inlet regulating valve, unit%; taking the total critical flow of the unit in unit percent, wherein X is an independent variable; the value of K is solved by the following formula:

the value of B is solved by the following formula:

the flow characteristic test calculation data under the condition of the overlapping degree of the steam inlet regulating valves can be removed by checking the working state of the sequence valve of the steam turbine, and the corresponding total critical flow when the (i) th steam inlet regulating valve starts to be opened and is fully opened is recorded and respectively marked as Frc_(i)sAnd Fr_c(i)eI is more than or equal to 1 and less than or equal to n, and n is the total number of the steam inlet regulating valves.

Optionally, the specific process of obtaining the overlap correction function of the steam turbine may be as follows: according to the first test data, acquiring the back pressure of the partially opened steam inlet regulating valve and the front-back pressure ratio of the regulating valve; determining the overlapping degree setting starting position and the overlapping degree setting ending position of two adjacent opened steam inlet regulating valves according to the valve back pressure of the partially opened steam inlet regulating valve and the front-to-back pressure ratio of the regulating valve; and determining an overlap correction function of the steam turbine according to the overlap area condition of the two adjacent opened steam inlet regulating valves.

In some embodiments, the partial open back pressure of the steam inlet regulating valve and the back-to-front pressure ratio of the regulating valve under the condition of the steam turbine sequence valve mode and the steam inlet regulating valve overlap degree removed can be calculated by the following steps:

i) calculating the steam inlet flow of the fully-opened steam inlet regulating valve under a certain state:

wherein, the symbol with lower angle mark '1' represents the parameter in the solving state, and the symbol with lower angle mark 'B' represents the reference valve point working condition when the critical pressure ratio is calculated; fr_1aRepresents the relative flow passing through the fully-opened steam inlet regulating valve under a certain test state, and the unit percent; epsilon_n1aThe relative pressure ratio of the fully-opened steam inlet regulating valve under a certain test state is shown and calculated by the formula (2).

ii) calculating the steam inlet flow rate through the partially opened steam inlet regulating valve under a certain state by the formula (6) as follows:

Fr_1b＝Fr₁-Fr₁a (6)

wherein Fr₁The relative flow, in units%, through all the admission control valves under a certain test condition can be calculated according to the formula (1).

iii) solving the relative pressure ratio corresponding to the regulating stage at the moment according to the steam inlet flow of the partially opened steam inlet regulating valve,getIt is possible to obtain:

iv) the pressure after partial opening of the admission control valve, i.e. the pressure before the regulating stage, is given by the following equation (7):

the corresponding front pressure of the adjusting stage can be solved according to the principle that the enthalpy value after the steam inlet adjusting valve is partially opened is the same as the enthalpy value of the main steamAnd substituting the relative pressure ratio calculation formula, and solving again until the error value of the two-time pressure ratio calculation is smaller than the specified error. At this time, the finally obtained pre-stage pressure and pre-stage temperature of the regulation are the final pressure and the final temperature after the steam inlet regulating valve is partially opened.

v) calculating the ratio of the front pressure to the rear pressure at the partial opening of the partially opened steam inlet regulating valve by the formula (8).

Thus, the pressure behind the inlet steam regulating valve which is partially opened and the pressure ratio between the front and the rear of the regulating valve can be obtained.

Then, each test condition data and the calculated front-back pressure ratio under partial opening of the steam inlet regulating valve can be observed, when the flow instruction is increased by 1%, the opening increasing rate of the previously opened steam inlet regulating valve exceeds a certain set rate value (for example, 8%, which can be set according to the field condition) and the valve front-back pressure ratio before the opening of the steam inlet regulating valve is increased is more than 87%, the critical flow value FO corresponding to the flow instruction (FOs) at the moment can be defined_csIs the initial position of the overlap, at which the corresponding opening degree of the former opening regulating valve is P_1sCritical flow command percentage F corresponding to the previous open regulating valve_rfcs(i)According to flow distribution function F_rfc(i)Calculation (X takes FO)_csValue) is obtained; critical flow command percentage F corresponding to the latter opening regulating valve_rfcs(i+1)Can be based on a flow distribution function F_rfc(i+1)Calculation (X takes FO)_csValue) was obtained.

Then, through equation (9), the flow command corresponding to the end position of the overlap degree area of the two steam inlet regulating valves is determined as follows:

in which FO is_s、FO_eFlow instructions corresponding to the initial and end positions of the overlapping degree area of two adjacent opened steam inlet adjusting valves are provided, and the unit is; p_1sThe opening degree of the previous opening regulating valve at the beginning of the overlapping degree area of the two steam inlet regulating valves is unit percent; s_VThe opening increase rate limit of the steam inlet regulating valve is set as unit%/%, when the flow instruction is increased by 1%.

Thus, the flow rate command FO corresponding to the end position can be set according to the degree of overlap_eAnd in combination with the sequence valve backpressure modification function F (x1), find the flow command FO_eCorresponding critical flow value FO_ceAt this time, the opening of the latter opening regulating valve is P_2e. In addition, the critical flow command percentage F corresponding to the later opening regulating valve_rfce(i+1)According to its flow distribution function F_rfc(i+1)Calculated to obtain (X takes FO)_ceValue), the critical flow command percentage F corresponding to the previously opened regulating valve_rfce(i)According to its flow distribution function F_rfc(i)Calculated to obtain (X takes FO)_ceValue).

Meanwhile, in the set overlap region, when the critical flow instruction percentage of the previous opened steam inlet regulating valve linearly changes along with the total critical flow and when the critical flow instruction percentage of the original steam inlet regulating valve is 100% (corresponding to the critical flow instruction percentage of the original steam inlet regulating valve)Total critical flow of Fr_c(i)e) The corresponding new critical flow command percentages are:

wherein, F_{rfc(i)_100％}The corresponding new critical flow instruction percentage is unit percent when the critical flow instruction percentage of the original steam inlet regulating valve is 100 percent; Δ F_c(i)The deviation value can be manually set and used for correcting the linearity of the valve opening and the flow command in the overlapping degree area, and the unit percent is calculated.

Thus, when there is only one overlap region between the previously opened steam inlet regulating valve and the adjacent steam inlet regulating valve, the overlap correction function of the previously opened steam inlet regulating valve in the overlap region is shown in the following table.

Watch 1

In addition, for the critical flow instruction percentage correction value of the later-opened steam inlet regulating valve in the set overlap degree area, if the critical flow instruction percentage of the later-opened steam inlet regulating valve in the set overlap degree area is linearly changed along with the total critical flow, the later-opened steam inlet regulating valve is originally opened and the critical flow instruction percentage is 0% (the corresponding total critical flow is Fr)_c(i)e) The critical flow command percentage (compared to the no overlap setting) is:

F_{rfc(i+1)-0％}＝100-F_{rfc(i)_100％}；

wherein, F_{rfc(i+1)-0％}The new critical flow instruction percentage is unit percent corresponding to the condition that the later steam inlet regulating valve is originally opened and the critical flow instruction percentage is 0 percent.

Thus, when the latter opened steam inlet regulating valve has only one overlap region with the adjacent steam inlet regulating valve, the overlap correction function of the latter opened steam inlet regulating valve in the overlap region is shown in the following table two.

Watch two

Percent original critical flow instruction (%)	Corrected critical flow command percentage (%)
		-600	0
Frfcs(i+1)	0
		0	Frfc(i+1)_0％
Frfce(i+1)	Frfce(i+1)
		100	100
800	100

It is worth mentioning that when a certain steam inlet regulating valve has an overlapping degree region with the previous steam inlet regulating valve and also has an overlapping degree region with the next steam inlet regulating valve, critical flow instruction percentage correction functions can be respectively determined and then combined (8 function points are obtained), so that a final correction function in the overlapping degree region is obtained.

Optionally, the specific process of obtaining the critical flow-opening function of the steam turbine may be as follows: according to the second test data, obtaining the critical flow of each steam inlet regulating valve in the stable state with different opening degrees; generating a curve of critical flow and opening according to the critical flow of each steam inlet regulating valve in a stable state with different openings; and determining a function of the curve of the critical flow and the opening as a critical flow-opening function of the steam turbine.

In some embodiments, after the second preset flow characteristic test is performed, based on the obtained second test data, the following formulas may be adopted to calculate the actual relative flow and the critical flow of each steam inlet regulating valve in different opening degree stable states.

The actual relative flow is calculated as follows:

wherein p is₂、υ₂、p_msRespectively the post-regulation pressure, the post-regulation specific volume and the main steam pressure, wherein the units are respectively MPa, m3/kg and MPa; the parameter indicated by the lower corner mark "0" represents the rated load state parameter.

The formula for calculating the critical flow is as follows:

wherein epsilon_n(vb)Representing the total pressure ratio of the admission control valve and the regulating stage,ε_nc(vb)representing the total critical pressure ratio of the regulating stage of the steam inlet regulating valve.

Then, a relative critical flow-regulating valve opening curve which meets the actual situation of the test can be drawn by using the obtained critical flow data calculated under each opening state, and the function corresponding to the curve is the regulating valve flow opening function F (x 4). In addition, relative critical flow can be obtained by taking the percentage of the relative flow value of each steam inlet regulating valve obtained by the test and the relative flow value under the full-open state of the steam inlet regulating valve.

Optionally, the specific processing for obtaining the single-valve flow correction function may be as follows: according to the second test data, acquiring actual relative flow and corresponding critical flow of each steam inlet regulating valve in a stable state with different opening degrees; generating curves of actual relative flow and critical flow according to the actual relative flow and the corresponding critical flow of each steam inlet regulating valve in the stable state with different opening degrees; and determining a function of the curves of the actual relative flow and the critical flow as a single valve flow correction function of the steam turbine.

In some embodiments, a relative flow-relative critical flow curve according with the actual test situation may be drawn according to the relative flow and critical flow data calculated under the opening state of each steam inlet regulating valve, and the function corresponding to the curve is the regulating valve single valve flow correction function F (x 3).

Step S120, inputting the received target flow instruction into an indirect steam distribution function group formed by sequentially connecting a sequence valve backpressure correction function, a flow distribution function and an overlap correction function to obtain a first intermediate instruction; and inputting the target flow instruction into the single valve flow correction function to obtain a second intermediate instruction.

And S130, obtaining an opening instruction of the steam inlet regulating valve according to the operation control mode of the steam turbine, the first intermediate instruction, the second intermediate instruction and the critical flow-opening function.

In some embodiments, corresponding instructions can be selected as input of the critical flow-opening function according to the specific operation control mode of the steam turbine so as to obtain the opening instruction of the steam inlet regulating valve.

Specifically, under the condition that the operation control mode of the steam turbine is the sequential valve regulation mode, the first intermediate instruction is input into the critical flow-opening function, and the opening instruction of the steam inlet regulating valve is obtained. And under the condition that the operation control mode of the steam turbine is a single-valve regulation mode, inputting the second intermediate instruction into the critical flow-opening function to obtain an opening instruction of the steam inlet regulating valve.

It should be noted that the sum of the obtained sequence valve backpressure correction function, flow distribution function, overlap correction function, single valve flow correction function, and critical flow-opening function of the steam turbine is the steam distribution function set in the indirect steam distribution mode, and the flow instruction of the steam turbine can be converted into the opening instruction of each steam inlet regulating valve through these functions.

As shown in fig. 2, a flow rate command processing flow in steps S120-S130 is shown, and the input flow rate command can be configured as an opening command of the steam inlet regulating valve through the steam distribution function set in the indirect steam distribution mode.

It should be noted that the flow distribution function and the overlap correction function in fig. 2 are serial structures, which are convenient for field implementation and low in implementation cost.

In the embodiment of the present invention, a sequence valve backpressure correction function, a flow distribution function, an overlap correction function, a single valve flow correction function, and a critical flow-opening function of a steam turbine may be obtained according to test data of a first preset flow characteristic test and a second preset flow characteristic test performed in advance. Then, the received target flow instruction may be input to an indirect steam distribution function group formed by sequentially connecting a sequence valve backpressure correction function, a flow distribution function, and an overlap correction function to obtain a first intermediate instruction, and the target flow instruction may be input to a single-valve flow correction function to obtain a second intermediate instruction. And finally, obtaining the opening instruction of the steam inlet regulating valve according to the operation control mode of the steam turbine, the first intermediate instruction, the second intermediate instruction and the critical flow-opening function.

Therefore, on the basis of field tests, theoretical calculation is combined, and through specific setting operation steps, the steam distribution function of the steam turbine in an indirect steam distribution mode can be measured and calculated, accurate quantitative data are provided for the steam turbine to optimize the steam distribution performance and the regulation performance of the steam turbine, accurate parameter setting can be provided for the optimization of the steam distribution and the regulation characteristics of the steam turbine, field implementation is facilitated, and the control effect of the steam inlet flow of the steam turbine is greatly improved.

In addition, the problems of specification setting and setting in the existing field are solved, and the flow of the steam turbine can be accurately controlled on the basis of field tests.

Based on the indirect steam distribution method of the steam inlet regulating valve provided by the embodiment, correspondingly, the invention also provides a specific implementation mode of the indirect steam distribution device of the steam inlet regulating valve applied to the indirect steam distribution method of the steam inlet regulating valve. Please see the examples below.

As shown in fig. 3, there is provided an indirect steam distribution device 300 of a steam inlet regulating valve, the device including:

the function obtaining module 310 is configured to obtain a sequence valve backpressure correction function, a flow distribution function, an overlap correction function, a single valve flow correction function, and a critical flow-opening function of the steam turbine according to test data of a first preset flow characteristic test and a second preset flow characteristic test which are performed in advance; the method comprises the following steps that a first preset flow characteristic test is carried out under the condition that the overlap degree of a steam inlet regulating valve is removed in the working state of a steam turbine sequence valve, and a second preset flow characteristic test is carried out under the working state of a single valve of the steam turbine;

the input module 320 is configured to input the received target flow instruction to an indirect steam distribution function group formed by sequentially connecting a sequence valve backpressure correction function, a flow distribution function, and an overlap correction function, so as to obtain a first intermediate instruction; inputting the target flow instruction into a single valve flow correction function to obtain a second intermediate instruction;

the instruction generating module 330 is configured to obtain an opening instruction of the steam inlet regulating valve according to the operation control mode of the steam turbine, the first intermediate instruction, the second intermediate instruction, and the critical flow-opening function.

Optionally, the function obtaining module is further configured to:

acquiring first test data of each steam inlet regulating valve under a plurality of opening degrees in a first preset flow characteristic test; the first test data at least comprises the pressure after the regulation stage, the temperature after the regulation stage, the main steam pressure, the main steam temperature and the opening degree of each steam inlet regulating valve;

acquiring a sequence valve backpressure correction function, a flow distribution function and an overlap correction function of the steam turbine according to the first test data;

acquiring second test data of each steam inlet regulating valve under a plurality of opening degrees in a second preset flow characteristic test; the second test data at least comprises the pressure after the regulation stage, the temperature after the regulation stage, the main steam pressure, the main steam temperature and the opening degree of each steam inlet regulating valve;

and acquiring a single valve flow correction function and a critical flow-opening function of the steam turbine according to the second test data.

Optionally, the function obtaining module is further configured to:

acquiring actual relative flow and corresponding total critical flow of each steam inlet regulating valve in an opening state according to the first test data;

generating a curve of the actual relative flow and the total critical flow according to the actual relative flow and the corresponding total critical flow of each steam inlet regulating valve in the opening state;

and determining a function of the curve of the actual relative flow and the total critical flow as a sequence valve back pressure correction function of the steam turbine.

Optionally, the function obtaining module is further configured to:

according to the first test data, acquiring the total critical flow corresponding to each steam inlet regulating valve when the steam inlet regulating valve starts to be opened and the total critical flow corresponding to each steam inlet regulating valve when the steam inlet regulating valve is fully opened;

and acquiring a flow distribution function of the steam turbine according to a preset corresponding relation between the total critical flow corresponding to the starting time and the total critical flow corresponding to the full starting time.

Optionally, the function obtaining module is further configured to:

according to the first test data, acquiring the back pressure of the partially opened steam inlet regulating valve and the front-back pressure ratio of the regulating valve;

determining the overlapping degree setting starting position and the overlapping degree setting ending position of two adjacent opened steam inlet regulating valves according to the valve back pressure of the partially opened steam inlet regulating valve and the front-to-back pressure ratio of the regulating valve;

and determining an overlap correction function of the steam turbine according to the overlap area condition of the two adjacent opened steam inlet regulating valves.

Optionally, the function obtaining module is further configured to:

according to the second test data, obtaining the critical flow of each steam inlet regulating valve in the stable state with different opening degrees;

generating a curve of critical flow and opening according to the critical flow of each steam inlet regulating valve in a stable state with different openings;

and determining a function of the curve of the critical flow and the opening as a critical flow-opening function of the steam turbine.

Optionally, the function obtaining module is further configured to:

according to the second test data, acquiring actual relative flow and corresponding critical flow of each steam inlet regulating valve in a stable state with different opening degrees;

generating curves of actual relative flow and critical flow according to the actual relative flow and the corresponding critical flow of each steam inlet regulating valve in the stable state with different opening degrees;

and determining a function of the curves of the actual relative flow and the critical flow as a single valve flow correction function of the steam turbine.

Optionally, the instruction generating module is further configured to:

under the condition that the operation control mode of the steam turbine is a sequence valve regulation mode, inputting a first intermediate instruction into a critical flow-opening function to obtain an opening instruction of a steam inlet regulating valve;

and under the condition that the operation control mode of the steam turbine is a single-valve regulation mode, inputting the second intermediate instruction into the critical flow-opening function to obtain an opening instruction of the steam inlet regulating valve.

In the embodiment of the present invention, a sequence valve backpressure correction function, a flow distribution function, an overlap correction function, a single valve flow correction function, and a critical flow-opening function of a steam turbine may be obtained according to test data of a first preset flow characteristic test and a second preset flow characteristic test performed in advance. Then, the received target flow instruction may be input to an indirect steam distribution function group formed by sequentially connecting a sequence valve backpressure correction function, a flow distribution function, and an overlap correction function to obtain a first intermediate instruction, and the target flow instruction may be input to a single-valve flow correction function to obtain a second intermediate instruction. And finally, obtaining the opening instruction of the steam inlet regulating valve according to the operation control mode of the steam turbine, the first intermediate instruction, the second intermediate instruction and the critical flow-opening function.

Therefore, on the basis of field tests, theoretical calculation is combined, and through specific setting operation steps, the steam distribution function of the steam turbine in an indirect steam distribution mode can be measured and calculated, accurate quantitative data are provided for the steam turbine to optimize the steam distribution performance and the regulation performance of the steam turbine, accurate parameter setting can be provided for the optimization of the steam distribution and the regulation characteristics of the steam turbine, field implementation is facilitated, and the control effect of the steam inlet flow of the steam turbine is greatly improved.

In addition, the problems of specification setting and setting in the existing field are solved, and the flow of the steam turbine can be accurately controlled on the basis of field tests.

FIG. 4 is a schematic illustration of a steam turbine provided in an embodiment of the present invention. As shown in fig. 4, the steam turbine 4 of this embodiment includes: a processor 40, a memory 41 and a computer program 42 stored in said memory 41 and executable on said processor 40. The processor 40, when executing the computer program 42, implements the steps of the above-described embodiments of the indirect steam distribution method for each of the steam admission control valves, such as steps 110 to 130 shown in fig. 1. Alternatively, the processor 40, when executing the computer program 42, implements the functions of the modules/units in the above-mentioned device embodiments, such as the functions of the modules 310 to 330 shown in fig. 3.

Illustratively, the computer program 42 may be partitioned into one or more modules/units that are stored in the memory 41 and executed by the processor 40 to implement the present invention. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions that describe the execution of the computer program 42 in the steam turbine 4. For example, the computer program 42 may be divided into the modules 310 to 340 shown in fig. 3.

The steam turbine may include, but is not limited to, a processor 40, a memory 41. Those skilled in the art will appreciate that FIG. 4 is merely exemplary of a steam turbine 4 and is not intended to be limiting of the steam turbine 4, and may include more or less components than illustrated, or some components in combination, or different components, for example, the steam turbine may also include input and output devices, network access devices, buses, and the like.

The Processor 40 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The storage 41 may be an internal storage unit of the turbine 4, such as a hard disk or a memory of the turbine 4. The memory 41 may also be an external storage device of the steam turbine 4, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), and the like, provided on the steam turbine 4. Further, the storage 41 may also include both an internal storage unit and an external storage device of the steam turbine 4. The memory 41 is used to store the computer program and other programs and data required by the steam turbine. The memory 41 may also be used to temporarily store data that has been output or is to be output.

It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working processes of the units and modules in the system may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

In the embodiments provided in the present invention, it should be understood that the disclosed apparatus/terminal device and method may be implemented in other ways. For example, the above-described embodiments of the apparatus/terminal device are merely illustrative, and for example, the division of the modules or units is only one logical division, and there may be other divisions when actually implemented, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated modules/units, if implemented in the form of software functional units and sold or used as separate products, may be stored in a computer readable storage medium. Based on such understanding, all or part of the flow in the method according to the above embodiment may be realized by a computer program, which may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the steps of the above-described indirect steam distribution method embodiment of the steam inlet regulating valve may be realized. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.