CN111927570A - Steam distribution curve optimization method for undisturbed switching of single valve/sequence valve of nozzle-regulated steam turbine - Google Patents
Steam distribution curve optimization method for undisturbed switching of single valve/sequence valve of nozzle-regulated steam turbine Download PDFInfo
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- CN111927570A CN111927570A CN202010802384.4A CN202010802384A CN111927570A CN 111927570 A CN111927570 A CN 111927570A CN 202010802384 A CN202010802384 A CN 202010802384A CN 111927570 A CN111927570 A CN 111927570A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D17/00—Regulating or controlling by varying flow
- F01D17/10—Final actuators
- F01D17/105—Final actuators by passing part of the fluid
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Abstract
The invention discloses a steam distribution curve optimization method for undisturbed switching of a single valve/sequence valve of a nozzle-regulated steam turbine, which comprises the following steps of: when the operating valve position instruction MR of the steam turbine is less than or equal to 40%, the steam distribution mode of the steam turbine is single-valve steam distribution; when the operating valve position instruction MR of the steam turbine is more than 40%, less than or equal to 45% or 50%, the steam distribution mode of the steam turbine is in a switching section from a single valve to a sequence valve; and when the operating valve position instruction MR of the steam turbine is more than 45% or 50%, the steam distribution mode of the steam turbine is gradually and automatically switched to sequence valve steam distribution. The undisturbed switching method can effectively solve various problems caused by the traditional manual switching method.
Description
Technical Field
The invention belongs to the technical field of steam turbines, and relates to a steam distribution curve optimization method for undisturbed switching of a single valve/sequence valve of a nozzle-regulated steam turbine.
Background
The single-valve steam distribution means that when the load of the unit changes, all the high-speed regulating valves of the steam turbine are opened and closed at the same time, the opening degree of the high-speed regulating valves is the same, and all the high-speed regulating valves are throttled at the same time to control the steam inlet quantity of the steam turbine. The steam distribution of the sequence valve, namely the high-speed regulating valve of the steam turbine is opened in sequence according to a certain sequence, the opening degrees of the high-speed regulating valves are different, the opening degree of the high-speed regulating valve which is opened firstly is large, the opening degree of the high-speed regulating valve which is opened later is small, and throttling exists only in the individual high-speed regulating valve in each load section.
When single valve steam distribution is carried out, the high-pressure cylinders of the steam turbine under each load section are all full-cycle steam admission, the cylinders are uniformly heated, the deformation of the cylinders is basically not influenced, but the high-pressure cylinder efficiency is obviously reduced due to the throttling of all high-pressure regulating valves, so that the heat consumption rate of the steam turbine is obviously increased, and the coal consumption of a unit is obviously increased. The steam distribution advantages and disadvantages of the sequence valve are just opposite.
The advantages and the disadvantages of single valve steam distribution and sequence valve steam distribution are comprehensively considered, and two high-pressure regulating valve steam distribution curves are generally configured in a DEH system of a nozzle regulating steam turbine set: one is a single valve steam distribution curve, and the other is a sequence valve steam distribution curve. When the unit is in a new production half year or in the speed-up and low-load stage after normal operation, a single-valve steam distribution curve is adopted from the safety perspective; and when the unit is normally put into operation and is more than a certain load, the steam distribution curve of the sequence valve is switched to from the economic point of view.
In the switching process of the single valve/sequence valve of the nozzle regulating steam turbine, the following problems mainly exist:
the switching process inevitably disturbs the unit load to a certain degree, and if the deviation between the actual flow characteristic of the high-speed regulating valve and the design characteristic is large or the actual flow characteristic curve of the high-speed regulating valve is steep, the single valve/sequence valve switching has a large influence on the load disturbance;
when power closed-loop control is put into before switching of the single valve/sequence valve, the disturbance of the switching on the unit load is improved, but the requirement on load adjustment precision is high, namely when the difference value between the actual load and the set load is greater than a certain value, the switching cannot be smoothly carried out;
the switching process of the single valve/sequence valve may cause certain influences on shaft vibration, tile temperature, axial displacement and expansion difference of the steam turbine #1/# 2;
in operation practice, in order to ensure the safety and reliability of the switching process, the requirement is not only on the duration time of the switching process, but also on the actual valve position instruction of the steam turbine. Under the new situation that peak regulation amplitude and energy conservation and consumption reduction pressure of a thermal power generating unit generally increase day by day, if a high-pressure-regulating-valve steam distribution mode is frequently switched in the normal operation process of the thermal power generating unit, the switching workload and the error probability of operating personnel can be increased undoubtedly, the operation safety risk of a steam turbine can be increased due to the normalization of switching operation, and the operation economy of the steam turbine can be reduced due to the fact that the switching operation is not timely.
The above problems of the conventional single valve/sequence valve switching manner of the nozzle-regulated steam turbine in operation practice cannot be completely and effectively solved by a simple manual switching method.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a steam distribution curve optimization method for the undisturbed switching of a single valve/sequence valve of a nozzle-regulated steam turbine, which can effectively solve various problems caused by a simple manual switching method.
In order to achieve the aim, the steam distribution curve optimization method for the undisturbed switching of the single valve/sequence valve of the nozzle regulating steam turbine comprises the following steps:
when the operating valve position instruction MR of the steam turbine is less than or equal to 40%, the steam distribution mode of the steam turbine is single-valve steam distribution; and when the operating valve position instruction MR of the steam turbine is more than 45% or 50%, the steam distribution mode of the steam turbine is automatically switched to sequence valve steam distribution.
And in the process of switching the single-valve steam distribution curve to the sequence valve steam distribution curve, adding a switching section with a valve position instruction interval of 5-10%.
In the process of determining the optimal valve sequence of the high-pressure regulating valve, economic factors need to be considered, and stability needs to be considered as much as possible so as to ensure that the safety indexes and the change trends of shafting of the steam distribution section of the switching section and the sequence valve meet the safety requirements (such as #1/#2 shaft vibration, bearing bush metal temperature, axial displacement, expansion difference and the like).
Before the high-speed regulating valve activity test is carried out, the main steam pressure bias or the test load condition is changed, so that the main valve position command can avoid a switching section and a transient unstable sequence valve steam distribution section during the test.
The invention has the following beneficial effects:
when the steam distribution curve optimization method for the undisturbed switching of the single valve/sequence valve of the nozzle adjusting steam turbine is in specific operation, when the operating valve position instruction MR of the steam turbine is more than 45% or 50%, the steam distribution mode of the steam turbine is automatically switched to the sequence valve steam distribution mode, so that the load disturbance caused by manual switching is fundamentally eliminated, the precision of load adjustment is improved, the switching process of the single valve/sequence valve can be automatically and timely carried out, operators do not need to carry out any manual switching work, the safety risk possibly caused by the manual switching (for example, indexes such as #1/#2 shaft vibration, bearing bush metal temperature, axial displacement, expansion difference and the like are abnormal) is eliminated, meanwhile, the automatic switching can be timely carried out even before and after rapid deep peak regulation, and the running economy of a unit is improved.
Drawings
FIG. 1 is a graph of undisturbed switching steam distribution of a single valve/sequence valve of a 600MW supercritical nozzle regulated turbine according to one embodiment;
FIG. 2 is a graph of undisturbed switching steam distribution of a single valve/sequence valve of a 1000MW ultra supercritical nozzle regulated turbine in the second embodiment.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings:
the invention relates to a steam distribution curve optimization method for undisturbed switching of a single valve/sequence valve of a nozzle adjusting steam turbine, which comprises the following steps of:
when the operating valve position instruction MR of the steam turbine is less than or equal to 40%, the steam distribution mode of the steam turbine is single-valve steam distribution; when the operating valve position instruction MR of the steam turbine is more than 40%, less than or equal to 45% or 50%, the steam distribution mode of the steam turbine is in a switching section from a single valve to a sequence valve; and when the operating valve position instruction MR of the steam turbine is more than 45% or 50%, the steam distribution mode of the steam turbine is automatically switched to sequence valve steam distribution.
In the process of converting the single-valve steam distribution curve into the sequence valve steam distribution curve, a switching section with a valve position instruction interval of 5-10% is added.
And determining the optimal valve sequence in a high-speed regulating valve sequence optimization test to ensure that the safety indexes and the change trends of shafting of the switching section and the sequence valve steam distribution section meet the safety requirements.
Before the high-speed regulating valve activity test is carried out, the main steam pressure bias or the test load condition is changed, so that the main valve position command avoids the switching section and the transient unstable sequence valve steam distribution section during the test.
Example one
Referring to fig. 1, fig. 1 shows a 600MW supercritical nozzle regulated turbine single valve/sequence valve undisturbed switching steam distribution curve. The steam turbine is in a medium pressure cylinder starting mode, when the total valve position instruction of the steam turbine is more than 0 and less than or equal to 20%, the opening degrees of the CV2, CV3, CV4 and CV1 high regulating valves are all 0, and the medium regulating valve instruction of the steam turbine is gradually increased from 0 to 100; when the total valve position instruction of the steam turbine is more than 20% and MR is less than or equal to 39.6%, the CV2, CV3, CV4 and CV1 high-speed regulating valves are synchronously opened and have consistent opening degrees, and the steam distribution mode of the steam turbine at the stage is a complete single-valve steam distribution mode; when the total valve position instruction of the steam turbine is 39.6% < MR < 45%, the opening degrees of CV2 and CV3 high-speed regulating valves are continuously increased, the CV4 and CV1 high-speed regulating valves are gradually closed, and the steam turbine is in a stage of switching from single-valve steam distribution to sequential valve steam distribution (the total valve position instruction interval of the switching section is 5.4%); when the total valve position instruction MR of the steam turbine is larger than or equal to 45%, the opening degree of the CV2 and CV3 high-pressure regulating valves is continuously increased along with the increase of the total valve position instruction MR of the steam turbine, the CV4 high-pressure regulating valves are gradually opened when the total valve position instruction MR of the steam turbine is increased to 48.6%, the CV1 high-pressure regulating valves are gradually opened when the total valve position instruction MR of the steam turbine is continuously increased to 81.5%, and the steam distribution mode of the steam turbine at the stage is a complete sequence valve steam distribution mode.
Example two
Referring to fig. 2, fig. 2 is a graph of undisturbed switching steam distribution of a single valve/sequence valve of a 1000MW ultra supercritical nozzle regulated steam turbine. When the total valve position command of the steam turbine is more than 0 and less than or equal to 40 percent, the CV2, the CV3, the CV4 and the CV1 high-speed regulating valves are synchronously opened and have consistent opening degrees, and the steam turbine steam distribution mode at this stage is a complete single-valve steam distribution mode; when the total valve position instruction of the steam turbine is 40% < MR < 48.6%, the opening degrees of CV2 and CV3 high-speed regulating valves are continuously increased, the CV4 and CV1 high-speed regulating valves are gradually closed, and the steam turbine is a single-valve steam distribution to sequence valve steam distribution switching section (the total valve position instruction interval of the switching section is 8.6%); when the total valve position instruction MR of the steam turbine is larger than or equal to 48.6%, the opening degree of CV2 and CV3 high-pressure regulating valves is continuously increased along with the increase of the total valve position instruction MR of the steam turbine, when the total valve position instruction MR of the steam turbine is increased to 51.8%, the CV4 high-pressure regulating valve is gradually opened, when the total valve position instruction MR of the steam turbine is continuously increased to 84.5%, the CV1 high-pressure regulating valve is gradually opened, and the steam distribution mode of the steam turbine at the stage is a complete sequence valve steam distribution mode.
Claims (4)
1. A steam distribution curve optimization method for undisturbed switching of a single valve/sequence valve of a nozzle-regulated steam turbine is characterized by comprising the following steps of:
when the operating valve position instruction MR of the steam turbine is less than or equal to 40%, the steam distribution mode of the steam turbine is single-valve steam distribution; and when the operating valve position instruction MR of the steam turbine is more than 45% or 50%, the steam distribution mode of the steam turbine is automatically switched to sequence valve steam distribution.
2. The method for optimizing the steam distribution curve of the undisturbed switching of the single valve/sequence valve of the nozzle regulated steam turbine as claimed in claim 1, wherein a switching section with a valve position command interval of 5-10% is added in the process of converting the single valve steam distribution curve to the sequence valve steam distribution curve.
3. The steam distribution curve optimization method for the undisturbed switching of the single valve/sequence valve of the nozzle regulated steam turbine according to claim 1, wherein an optimal valve sequence is determined in a valve sequence optimization test to ensure that the safety indexes and the change trends of shafting of the switching section and the steam distribution section of the sequence valve meet the safety requirements.
4. The method for optimizing the steam distribution curve for the undisturbed switching of the single valve/sequence valve of the nozzle regulated steam turbine according to claim 1, wherein the total valve position command avoids the switching section and the transient unstable sequence valve steam distribution section during the test by changing the main steam pressure bias or the test load condition before the high-speed governor valve activity test is carried out.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114943127A (en) * | 2022-06-28 | 2022-08-26 | 西安热工研究院有限公司 | Calculation method for correcting steam turbine sequence valve state to single valve state |
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| CN103046972A (en) * | 2012-12-13 | 2013-04-17 | 哈尔滨工业大学 | Nonlinear automatic undisturbed single valve/sequence valve switching method for steam turbine |
| JP2014037816A (en) * | 2012-08-20 | 2014-02-27 | Toshiba Corp | Valve control device and valve control method |
| CN106968727A (en) * | 2017-02-06 | 2017-07-21 | 广东红海湾发电有限公司 | Steam turbine match somebody with somebody vapour method and steam distribution system |
| CN107143387A (en) * | 2017-05-08 | 2017-09-08 | 西安西热节能技术有限公司 | A kind of full admission throttle-governed turbine matches somebody with somebody vapour determination method for parameter |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101644173A (en) * | 2009-09-09 | 2010-02-10 | 东北电力大学 | Method for optimizing steam distribution way of steam turbine |
| JP2014037816A (en) * | 2012-08-20 | 2014-02-27 | Toshiba Corp | Valve control device and valve control method |
| CN103046972A (en) * | 2012-12-13 | 2013-04-17 | 哈尔滨工业大学 | Nonlinear automatic undisturbed single valve/sequence valve switching method for steam turbine |
| CN106968727A (en) * | 2017-02-06 | 2017-07-21 | 广东红海湾发电有限公司 | Steam turbine match somebody with somebody vapour method and steam distribution system |
| CN107143387A (en) * | 2017-05-08 | 2017-09-08 | 西安西热节能技术有限公司 | A kind of full admission throttle-governed turbine matches somebody with somebody vapour determination method for parameter |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114943127A (en) * | 2022-06-28 | 2022-08-26 | 西安热工研究院有限公司 | Calculation method for correcting steam turbine sequence valve state to single valve state |
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