CN109184818B - Back pressure turbine blade protection method based on turbine speed regulation system - Google Patents
Back pressure turbine blade protection method based on turbine speed regulation system Download PDFInfo
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- CN109184818B CN109184818B CN201810896420.0A CN201810896420A CN109184818B CN 109184818 B CN109184818 B CN 109184818B CN 201810896420 A CN201810896420 A CN 201810896420A CN 109184818 B CN109184818 B CN 109184818B
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- turbine
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- differential pressure
- steam
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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
- F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
- F01D21/003—Arrangements for testing or measuring
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D17/00—Regulating or controlling by varying flow
- F01D17/10—Final actuators
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- 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
- F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
- F01D21/14—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for responsive to other specific conditions
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2270/00—Control
- F05D2270/30—Control parameters, e.g. input parameters
- F05D2270/301—Pressure
- F05D2270/3015—Pressure differential pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2270/00—Control
- F05D2270/70—Type of control algorithm
- F05D2270/706—Type of control algorithm proportional-integral-differential
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Turbines (AREA)
Abstract
The invention relates to a safety protection method for a steam turbine. The method can control the differential pressure value of the wheel chamber pressure and the exhaust steam pressure within a certain safety range, avoid the phenomenon that the exhaust steam pressure fluctuates greatly due to the fact that the inlet steam pressure fluctuates greatly, trigger the exhaust steam pressure protection action to cause the emergency shutdown of the steam turbine, and ensure the normal operation of the back pressure steam turbine. The technical scheme is as follows: a back pressure turbine blade protection method based on a turbine speed regulation system is carried out according to the following steps: 1) pressure sensors are respectively arranged on a turbine wheel chamber and a turbine exhaust port, and signals obtained by the two pressure sensors are respectively input into a turbine speed regulating system; a rotating speed sensor is arranged on the steam turbine, and an actual rotating speed signal obtained by the rotating speed sensor is input into a steam turbine speed regulating system; 2) the steam turbine speed regulating system carries out logical operation on signals input by the two pressure sensors to obtain a differential pressure value delta P.
Description
Technical Field
The invention relates to a safety protection method for a steam turbine, in particular to a protection method for a back pressure type steam turbine blade.
Background
The steam turbine with the exhaust pressure greater than the atmospheric pressure is called a back pressure steam turbine; the exhaust steam of the back pressure steam turbine can be used for supplying heat or supplying the original medium and low pressure steam turbines to replace medium and low pressure boilers of old power plants, so that the heat efficiency is higher than that of a condensing steam turbine. However, when the back pressure turbine operates, the problem of overlarge stress of the blade caused by overlarge differential pressure of the front and rear stages can occur, and the safe operation of the turbine is endangered.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the method can control the differential pressure value of the wheel chamber pressure and the exhaust steam pressure within a certain safety range, avoid the phenomenon that the exhaust steam pressure fluctuates greatly due to the large fluctuation of the steam inlet pressure, trigger the emergency shutdown of the steam turbine caused by the protection action of the exhaust steam pressure, and ensure the normal operation of the back pressure steam turbine.
The technical scheme provided by the invention is as follows:
a back pressure turbine blade protection method based on a turbine speed regulation system is carried out according to the following steps:
1) pressure sensors are respectively arranged on a turbine wheel chamber and a turbine exhaust port, and signals obtained by the two pressure sensors are respectively input into a turbine speed regulating system;
a rotating speed sensor is arranged on the steam turbine, and an actual rotating speed signal obtained by the rotating speed sensor is input into a steam turbine speed regulating system;
2) the steam turbine speed regulating system carries out logical operation on signals input by the two pressure sensors to obtain a differential pressure value delta P;
3) the speed regulating system of the steam turbine carries out the following treatment:
(1) the differential pressure value delta P is greater than or equal to the differential pressure alarm value delta PAOutputting an alarm signal to an alarm device to trigger alarm;
(2) the differential pressure value delta P is greater than or equal to the differential pressure shutdown value delta PTOutputting a shutdown signal to a turbine emergency shutdown system to trigger shutdown, and triggering an alarm by a shunt lock;
(3) inputting a differential pressure value delta P as a differential pressure actual value signal and a given differential pressure value delta SP signal into a differential pressure control PID, and outputting an obtained output signal of the differential pressure control PID to a low selection module LSS;
inputting a rotating speed actual value signal and a rotating speed set value signal of the steam turbine into a differential control PID, and outputting an obtained output signal of the differential control PID to a low selection module LSS;
and the low selection module processes signals input by the two PIDs, and takes a smaller control signal as a final control signal to be output to an actuating mechanism of the steam turbine.
The pressure sensor is an intelligent pressure transmitter.
The speed control system of the steam turbine performs three-sampling-and-centering processing on signals obtained by the three speed sensors, and the obtained signals are used as actual speed signals to be input into a speed PID.
The differential pressure control PID and the rotating speed control PID are both set by software of a steam turbine speed regulating system.
The low selection module is formed by software of a speed regulating system of the steam turbine.
The invention has the beneficial effects that: because the back pressure turbine is additionally provided with the blade protection system, the online monitoring of the differential pressure value of the wheel chamber pressure and the exhaust steam pressure can be realized; once the differential pressure value exceeds a set value, the turbine speed regulating system can be shut down, so that the phenomenon that the turbine is shut down emergently due to triggering of the protection action of the exhaust steam pressure caused by the large fluctuation of the exhaust steam pressure due to the large fluctuation of the inlet steam pressure can be avoided to the maximum extent; and the control precision is high, the stability is good, and the safe operation of the steam turbine is ensured. In addition, the blade protection system is established on the basis of the original hardware, so that the blade protection system is good in compatibility with the original system, convenient to debug and low in investment cost.
Drawings
Fig. 1 is a schematic diagram of the connection relationship of the present invention.
FIG. 2 is a flow chart of the logic operation of the present invention.
In the figure: p1 is wheel chamber pressure; p2 is the exhaust pressure.
Detailed Description
The following further description is made with reference to the embodiments shown in the drawings.
The existing back pressure turbines are all provided with a turbine speed regulating system (DEH system) and a turbine emergency shutdown system (ETS system); the inlet steam (input steam) enters the steam turbine to work after passing through the quick closing valve and the steam regulating valve in sequence; the method comprises the steps that three rotating speed sensors arranged on a steam turbine are used for obtaining rotating speed signals, the rotating speed signals are input into a steam turbine speed regulating system, the steam turbine speed regulating system is processed through three-step selection (removing the size and taking signals of a second numerical value), the rotating speed signals are used as rotating speed actual value signals and input into a rotating speed control PID (Proportion Integration Differentiation) together with rotating speed set value signals, the rotating speed actual value signals are set by steam turbine speed regulating system software, one path of rotating speed control signals are output to a regulating steam valve after processing, the steam inlet quantity input into the steam turbine is regulated, and therefore the rotating speed of the steam turbine is regulated.
However, the above-described rotational speed control system does not have a blade protection function.
The control method adopted by the invention is as follows:
two intelligent pressure transmitters are used for respectively measuring the pressure of a wheel chamber and the exhaust pressure, and the two transmitters respectively output a 4-20mA current signal corresponding to the actual pressure. The signal is input into a turbine speed regulating system through an IO card of the turbine speed regulating system, and compared and logically operated by a differential pressure control PID (set by turbine speed regulating system software) to generate a differential pressure value delta P, wherein an alarm signal is sent out when the differential pressure value delta P is greater than a differential pressure alarm value delta PA, and a stop signal is sent out to a turbine emergency stop system when the differential pressure value delta P is greater than a differential pressure stop value delta PT. The differential pressure value delta P signal and the differential pressure given value delta SP signal of the control system are sent to a differential pressure control PID together, and one path of differential pressure control signal is output after processing.
The rotating speed control signal output by the rotating speed control PID and the differential pressure control signal output by the differential pressure control PID are processed by a low selection module (set by software of a control system), and the path of control signal with the smaller value of the rotating speed control PID and the differential pressure control signal is output to an actuating mechanism (a regulating steam valve) of the steam turbine as a final control signal to regulate the steam inlet quantity input to the steam turbine.
The wheel chamber pressure and the steam exhaust pressure are obtained by respectively arranging a pressure sensor PT at the wheel chamber of the steam turbine and a steam exhaust port of the steam turbine and detecting by the two pressure sensors; the two pressure sensors are respectively connected to a steam turbine speed regulating system through data lines so as to carry out online monitoring.
The invention adds the blade protection function to the rotating speed control system of the back pressure turbine; and when the speed regulating system of the steam turbine regulates the rotating speed, the differential pressure value between the wheel chamber pressure and the exhaust steam pressure is subjected to low selection regulation, and the differential pressure value delta P (P1-P2) of the wheel chamber pressure and the exhaust steam pressure is controlled within a certain safety range. When the differential pressure value between the wheel chamber pressure of the steam turbine and the exhaust steam pressure is greater than or equal to the differential pressure alarm value delta PATriggering alarm, when the differential pressure value between the pressure of the wheel chamber of the steam turbine and the exhaust pressure is greater than or equal to the differential pressure stop value delta PTTriggering the shutdown output and interlocking the shutdown.
In the operation process of the steam turbine, the differential pressure value between the pressure of the wheel chamber and the exhaust pressure is ensured to be delta PAThe turbine can be effectively prevented from being caused by the front and rear stagesThe large differential pressure causes damage to the turbine blades.
Therefore, the invention can utilize the existing speed regulating system (DEH) of the steam turbine, does not need to increase special hardware, only needs to ensure that enough analog quantity input channels of 4-20mA exist, converts the monitored wheel chamber pressure P1 and the exhaust pressure P2 into 4-20mA, and sends the 4-20mA to the speed regulating system of the steam turbine; and corresponding software improvement is carried out on the existing speed regulating system of the steam turbine, and a differential pressure control frequency converter and a low selection module are added. The method can not only protect the turbine blades, but also prevent the turbine from emergency shutdown caused by the protection action of the exhaust steam pressure due to the large fluctuation of the inlet steam pressure of the turbine to the maximum extent in the allowable safety range of the turbine.
Finally, it should be noted that the above-mentioned list is only a specific embodiment of the present invention. It is obvious that the present invention is not limited to the above embodiments, but many variations are possible. All modifications which can be derived or suggested by a person skilled in the art from the disclosure of the present invention are to be considered within the scope of the invention.
Claims (5)
1. A back pressure turbine blade protection method based on a turbine speed regulation system is carried out according to the following steps:
1) pressure sensors are respectively arranged on a turbine wheel chamber and a turbine exhaust port, and signals obtained by the two pressure sensors are respectively input into a turbine speed regulating system;
a rotating speed sensor is arranged on the steam turbine, and an actual rotating speed signal obtained by the rotating speed sensor is input into a steam turbine speed regulating system;
2) the steam turbine speed regulating system carries out logical operation on signals input by the two pressure sensors to obtain a differential pressure value delta P;
3) the speed regulating system of the steam turbine carries out the following treatment:
(1) the differential pressure value delta P is greater than or equal to the differential pressure alarm value delta PAOutputting an alarm signal to an alarm device to trigger alarm;
(2) the differential pressure value delta P is greater than or equal to the differential pressure shutdown value delta PTOutputting a stop signal to the emergency stop system of the steam turbine to trigger the stop, andthe alarm is triggered in an interlocking way;
(3) inputting a differential pressure value delta P serving as a differential pressure actual value signal and a given differential pressure value signal delta SP into a differential pressure control proportional-integral-derivative module, and inputting an obtained differential pressure control output signal to a low selection module;
inputting a rotating speed actual value signal and a rotating speed set value signal of the steam turbine into a rotating speed control proportional-integral-derivative module, and inputting an obtained rotating speed control output signal to a low selection module;
and the low selection module processes the signals input by the two proportional-integral-derivative modules, and takes a smaller signal as a final control signal to be output to an actuating mechanism of the steam turbine.
2. The method for protecting back pressure turbine blades based on a turbine governor system of claim 1, wherein: the pressure sensor is an intelligent pressure transmitter.
3. The method for protecting back pressure turbine blades based on a turbine governor system of claim 2, wherein: the speed control system comprises three speed sensors, a steam turbine speed control system performs three-taking-in-middle processing on signals obtained by the three speed sensors, and the obtained signals are input into a speed control proportional-integral-derivative module as actual speed signals.
4. The method for protecting back pressure turbine blades based on a turbine governor system of claim 3 wherein: the differential pressure control proportional-integral-derivative module and the rotating speed control proportional-integral-derivative module are both formed by software of a steam turbine speed regulating system.
5. The method for protecting back pressure turbine blades based on a turbine governor system of claim 4 wherein: the low selection module is formed by software of a speed regulating system of the steam turbine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810896420.0A CN109184818B (en) | 2018-08-08 | 2018-08-08 | Back pressure turbine blade protection method based on turbine speed regulation system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810896420.0A CN109184818B (en) | 2018-08-08 | 2018-08-08 | Back pressure turbine blade protection method based on turbine speed regulation system |
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| Publication Number | Publication Date |
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| CN109184818A CN109184818A (en) | 2019-01-11 |
| CN109184818B true CN109184818B (en) | 2020-11-17 |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE757455A (en) * | 1969-10-16 | 1971-03-16 | Westinghouse Electric Corp | ANTI-RIGGING SYSTEM FOR |
| CN201043476Y (en) * | 2007-04-10 | 2008-04-02 | 杭州中能汽轮动力有限公司 | Front pressure regulating mechanism of pure low-temperature waste heat turboset |
| CN106089326B (en) * | 2016-08-15 | 2018-01-16 | 鞍钢集团工程技术有限公司 | Dry coke quenching heat recovery steam electric turbine enters, steam discharge control method |
| CN108240238B (en) * | 2016-12-26 | 2020-11-24 | 上海电气电站设备有限公司 | Control system and control method for steam turbine of extraction back pressure water feeding pump and steam turbine |
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