阅读说明：本技术 一种火力发电厂汽轮机进汽温度测量控制系统 (Steam inlet temperature measurement control system of steam turbine of thermal power plant ) 是由 刘锋 王超 唐田 金晶 李渊 于 2021-07-19 设计创作，主要内容包括：一种火力发电厂汽轮机进汽温度测量控制系统,包括：进汽管道、热电偶、保护套管、补偿导线和DCS控制装置；DCS控制装置包括接线端子板、连接电缆、温度卡件、通道背板和主控制器,主控制器中含有用于对接收到的信号进行逻辑运算的逻辑模块,热电偶的正负极两个输出端子按照正对正、负对负的方式连接补偿导线两芯的其中一端,补偿导线两芯的另外一端按照正对正、负对负的方式连接端子板的接线端子,端子板再通过连接电缆与温度卡件连接,温度卡件和主控制器插在背板的插槽上。本发明极大地提高了蒸汽温度变化监视的准确性和汽轮机防进水保护动作的可靠性。(A steam turbine admission temperature measurement control system of a thermal power plant comprises: the device comprises a steam inlet pipeline, a thermocouple, a protective sleeve, a compensation lead and a DCS control device; the DCS control device comprises a terminal board, a connecting cable, a temperature clamping piece, a channel back board and a main controller, wherein the main controller comprises a logic module used for carrying out logic operation on received signals, two output terminals of a positive electrode and a negative electrode of a thermocouple are connected with one end of two cores of a compensation lead in a positive alignment mode and a negative alignment mode, the other end of the two cores of the compensation lead is connected with a wiring terminal of the terminal board in a positive alignment mode and a negative alignment mode, the terminal board is connected with the temperature clamping piece through the connecting cable, and the temperature clamping piece and the main controller are inserted into a slot of the back board. The invention greatly improves the accuracy of monitoring the steam temperature change and the reliability of the water inlet prevention protection action of the steam turbine.)

1. The utility model provides a steam turbine admission temperature measurement control system of thermal power factory, characterized by: the main controller BRC400(205) comprises a logic module (206), the logic module comprises a first to a fifth large value taking module, a first to a fifteenth DELAY module DELAY and a subtraction module, and the connection mode is as follows:

the system comprises first to fourth delay modules (20601 to 20604), a first maximum value taking module (206100), fifth to seventh delay modules (20605 to 20607), a second maximum value taking module (206200), eighth to tenth delay modules (20608 to 20610), a third maximum value taking module (206300), eleventh to thirteenth delay modules (20611 to 20613), a fourth maximum value taking module (206400), fourteenth to fifteenth delay modules (20614 to 20615) and a fifth maximum value taking module (206500), which are connected in sequence, and then the maximum value of the temperature in 10 minutes is output to a subtraction module (206600);

wherein: the first time delay module inputs the steam inlet temperature of the steam turbine, the first to third time delay modules are also respectively connected to the first large value taking module, the fifth time delay module, the sixth time delay module are also respectively connected to the second large value taking module, the eighth time delay module, the ninth time delay module are also respectively connected to the third large value taking module, the eleventh time delay module, the twelfth time delay module are also respectively connected to the fourth large value taking module, and the fourth large value taking module and the fourteenth time delay module are also respectively connected to the fifth large value taking module;

and the subtraction module also inputs the steam inlet temperature at the same time, and the final output result is the steam temperature drop value within 10 minutes.

2. The steam turbine inlet temperature measurement control system of a thermal power plant according to claim 1, characterized in that: the delay time of the delay module in the logic module is set as follows: the delay time of the first delay module, the second delay module, the third delay module and the fourth delay module is 1 second; the delay time of the fifth, sixth and seventh delay modules is 4 seconds; the delay time of the eighth delay module, the ninth delay module and the tenth delay module is 16 seconds; the delay time of the eleventh delay module, the twelfth delay module and the thirteenth delay module is 60 seconds; the delay time of the fourteenth and fifteenth delay modules is 180 seconds.

3. The steam turbine inlet temperature measurement control system of the thermal power plant according to claim 1 or 2, characterized in that: the thermocouple is K in indexing type, II in precision grade and 0-800 ℃ in measuring range.

4. The steam turbine inlet temperature measurement control system of the thermal power plant according to claim 1 or 2, characterized in that: the compensating conductor has a model of KX-HS-FFP 2x1.0mm²。

Technical Field

The invention relates to a steam inlet temperature measurement control system of a steam turbine of a thermal power plant.

Background

The temperature monitoring of the steam of the thermal power plant has great reference significance for judging whether the steam turbine enters water or not. High-temperature and high-pressure steam generated by boiler combustion enters a steam turbine through a steam inlet pipeline, and the steam temperature is deviated from a rated parameter and generally does not exceed 20 ℃ in the normal operation process of a unit. When the steam temperature drops too much, especially when the degree of hypothermia exceeds the degree of superheat, the steam turbine runs the risk of water inflow. According to the stipulation of twenty-five countermeasures 8.3.4, when the unit normally operates, the temperature of main and reheated steam is suddenly reduced by 50 ℃ within 10 minutes, and the steam turbine should be immediately opened. The temperature monitoring and measuring of the main and reheated steam in the existing thermal power plant has the following problems:

in the first part of the power plant, a temperature measuring point is introduced into a control system through a measuring device to monitor an instantaneous value, and the drop value of the temperature of main reheat steam and reheat steam within 10 minutes can not be monitored.

And secondly, after the temperature of part of power plants is introduced into the control system, monitoring and alarm protection are carried out on the reduction values of the main and reheated steam temperatures within 10 minutes based on a logic module of the control system, but the time precision is low, and the alarm protection action is unreliable.

And thirdly, after the temperature of part of power plants is introduced into the control system, monitoring and alarm protection are carried out on the steam temperature reduction value within 10 minutes based on a logic module of the control system, the time precision meets the requirement, but the configuration program is long, a large amount of load rate and block address of the controller are occupied, and the controller is easy to crash.

In order to improve the monitoring accuracy of the steam temperature drop value within 10 minutes and ensure the reliability of the alarm protection action, a proper measuring instrument and a reliable control system need to be selected, and meanwhile, a proper logic module needs to be combined to accurately monitor the steam temperature drop value within 10 minutes.

Disclosure of Invention

The invention aims to solve the technical problem of providing a steam inlet temperature measurement control system of a steam turbine of a thermal power plant, which can accurately measure the specific value of steam temperature reduction within 10 minutes, improve the accuracy of parameter monitoring and ensure the reliability of alarm protection action.

The technical scheme adopted by the invention is as follows:

the utility model provides a steam turbine admission temperature measurement control system of thermal power factory, characterized by includes:

the measuring instrument is used for extending into and measuring the temperature of steam in a steam inlet pipeline (1) for conveying high-temperature and high-pressure steam, which is arranged on a steam turbine of a thermal power plant;

a protection sleeve (3) which is sleeved outside the thermocouple and used for assisting in measurement and protecting the thermocouple;

a measuring instrument K graduation thermocouple 2 used for extending into and measuring the temperature of the steam in the steam inlet pipeline;

a protection sleeve 3 which is sleeved outside the thermocouple 2 and used for assisting in measurement and protecting the thermocouple 2;

a two-core compensation lead 4 for transmitting and compensating the output signal measured by the thermocouple 2;

a DCS control device 5 for receiving the measuring signal transmitted by the compensation wire 4 and carrying out processing conversion and logic operation on the measuring signal;

the DCS control device 5 further includes a terminal block NTAI 06201, a cable NKAS 01202, a temperature clamping piece ASI 23203, a back plate MMU 22204, and a main controller BRC 400205 (all the devices in fig. 2 are part of a DCS control system, the above-mentioned part is hardware necessary for measuring temperature, and the DCS control system further includes many other devices);

the two output terminals of the positive and negative electrodes of the thermocouple 2 are connected with one end of two cores of the compensation lead 4 in a positive-positive and negative-negative mode, the other end of the two cores of the compensation lead 4 is connected with a connecting terminal of a terminal board NTAI 06201 in a DCS control system in a positive-positive and negative-negative mode, the terminal board NTAI 06201 is connected with a temperature clamping piece ASI 23203 through a connecting cable NKAS 01202, and the temperature clamping piece ASI 23203 and the main controller BRC 400205 are inserted into a slot of a back plate MMU 22204.

The main controller BRC 400205 includes a logic module 206, the logic module 206 includes a plurality of modules for taking a large value, a plurality of DELAY modules DELAY, and a subtraction module, and the connection mode is:

the input temperature measured from the thermocouple 2 is transmitted to the first to fourth delay modules 20601 to 20604, the first maximum value module 206100, the fifth to seventh delay modules 20605 to 20607, the second maximum value module 206200, the eighth to tenth delay modules 20608 to 20610, the third maximum value module 206300, the eleventh to thirteenth delay modules 20611 to 20613, the fourth maximum value module 206400, the fourteenth to fifteenth delay modules 20614 to 20615, and the fifth maximum value module 206500, which are connected in sequence, and then the maximum value of the temperature in 10 minutes is output to the subtraction module 206600;

wherein: the first to third delay modules are also respectively connected to the first big value taking module, the fifth delay module and the sixth delay module are also respectively connected to the second big value taking module, the eighth delay module and the ninth delay module are also respectively connected to the third big value taking module, the eleventh delay module and the twelfth delay module are also respectively connected to the fourth big value taking module, and the fourth big value taking module and the fourteenth delay module are also respectively connected to the fifth big value taking module;

and the subtraction module also simultaneously inputs the input temperature measured by the thermocouple 2, and the final output result is the steam temperature drop value within 10 minutes.

The delay time setting of the delay module in the logic module 206: the delay time of the first delay module, the second delay module, the third delay module and the fourth delay module is 1 second; the delay time of the fifth, sixth and seventh delay modules is 4 seconds; the delay time of the eighth delay module, the ninth delay module and the tenth delay module is 16 seconds; the delay time of the eleventh delay module, the twelfth delay module and the thirteenth delay module is 60 seconds; the delay time of the fourteenth and fifteenth delay modules is 180 seconds.

The graduation model of the thermocouple 2 is K, the precision grade is II grade, and the measuring range is 0-800 ℃.

The compensating lead 4 has the model number KX-HS-FFP 2x1.0mm²。

Has the advantages that: the invention applies a reliable measurement control system for improving the accuracy of steam temperature monitoring and ensuring the reliability of the water inlet prevention alarm protection action of the steam turbine, and has the main advantages that:

1) the method can accurately measure the drop value of the monitored steam temperature within 10 minutes, and ensures the accuracy of parameter monitoring and the reliability of alarm protection action.

2) The control system has reliable protection and alarm functions, and the time precision is improved to 1 second.

3) The main controller runs stably, the load occupancy rate is low, and the block address occupancy rate is low.

Drawings

The invention is described in further detail below with reference to the following figures and specific examples:

FIG. 1 is a flow chart of the steam temperature measurement of the present invention;

FIG. 2 is a schematic diagram of the components and connection relationship of the steam inlet temperature measurement control system of the steam turbine of the thermal power plant;

FIG. 3 is a logic module connection diagram of the steam turbine inlet temperature measurement control system of the thermal power plant.

Description of reference numerals:

1-an steam inlet pipeline, 2-a thermocouple, 3-a protective sleeve, 4-a compensation wire and 5-a DCS control device;

201-terminal board NTAI06, 202-connection cable NKAS01, 203-temperature card ASI23, 204-backplate MMU22, 205-main controller BRC400, 206-logic module;

20601 to 20615-first to fifteenth DELAY modules DELAY, 206100 to 206500-first to fifth maximum value modules; 206600-subtraction module.

The specific implementation mode is as follows:

embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and detailed description.

High-temperature and high-pressure steam generated by boiler combustion enters a steam turbine through a steam inlet pipeline, in order to measure the temperature of the steam in the steam inlet pipeline 1, a temperature thermocouple protective sleeve 3 is inserted into the steam inlet pipeline 1, and a temperature thermocouple 2 is inserted into the protective sleeve 3. Because the measuring cold end of the temperature thermocouple 2 is not 0 ℃, the measuring cold end of the temperature thermocouple 2 is extended to the DCS control device 5 through the compensating lead 4, and meanwhile, the compensating lead 4 also has the function of transmitting the measuring output electric signal of the temperature thermocouple 2, the DCS control device 5 carries out processing conversion and logic operation on the received measuring output signal, and transmits the final result to a production process control object for control or an operator station for monitoring.

The system embodiment of the present invention as shown in fig. 1 to 2 comprises: the measuring instrument K graduation thermocouple 2 used for measuring the steam temperature in the admission line, its overcoat is used for assisting and measuring and protecting the protective sleeve 3 of the thermocouple 2, insert in the admission line 1 used for conveying high-temperature high-pressure steam together with the two; a compensation lead 4 for transmitting and compensating the output signal measured by the thermocouple 2; and the DCS control device 5 is used for receiving the measurement signal transmitted by the compensation conductor 4 and carrying out processing conversion and logic operation on the measurement signal.

The circuit part in the DCS control device 5 includes: a terminal board NTAI 06201 for connecting the compensation conductor 4 and receiving the measured output electrical signal; a connecting cable NKAS 01202 for transmitting the electric signal of the terminal board NTAI 06201 to the card; the temperature clamping piece ASI 23203 is used for receiving the electric signal transmitted by the connecting cable NKAS 01202 and converting the electric signal into a digital signal; a channel backplane MMU 22204 for transmitting the digital signal output by the temperature card ASI 23203; a main controller BRC 400205 for receiving digital signals passed by the backplane MMU 22204; a logic block 206 loaded in the processing main controller BRC 400205 for performing a logic operation on the received signal.

The system logic module 206 of the present invention as shown in FIG. 3 includes: fifteen delay modules, five large value taking modules and a subtraction module, wherein the connection mode is as follows:

the input temperature and the first, second, third and fourth DELAY modules DELAY are sequentially connected, and the outputs of the four DELAY modules DELAY are connected to the first large value taking module; the output of the first large value taking module and the fifth, sixth and seventh DELAY modules are connected in sequence; the output of the first big value taking module and the outputs of the fifth, sixth and seventh DELAY modules DELAY are connected to the second big value taking module; the output of the second large value taking module and the eighth, ninth and tenth DELAY modules DELAY are connected in sequence; the output of the second maximum value module and the output of the eighth DELAY module, the ninth DELAY module and the tenth DELAY module are connected to the third maximum value module; the output of the third large value taking module and the eleventh, twelfth and thirteenth DELAY modules DELAY are connected in sequence; the output of the third large value taking module and the output of the eleventh, twelfth and thirteenth DELAY modules DELAY are connected to the fourth large value taking module; the output of the fourth large value taking module and the fourteenth and fifteenth DELAY modules DELAY are connected in sequence; the output of the fourth large value taking function block and the outputs of the fourteenth and fifteenth DELAY function blocks DELAY are connected to the fifth large value taking function block; fifthly, the output temperature of the large-value function block is the maximum value of the temperature within 10 minutes; the input temperature and the output temperature are connected to a subtraction module, and the output result is the steam temperature drop value within 10 minutes.

Working process

Referring to fig. 1, a thermocouple 2 is inserted into a protective sleeve 3, the temperature of steam in an inlet pipe 1 is measured through the protective sleeve 3, the thermocouple 2 converts the measured temperature into an output electrical signal of millivolt level based on thermoelectric effect, and two output terminals of the thermocouple 2 are connected with one end of two cores of a compensation wire 4 in positive alignment and negative alignment and are transmitted to a DCS control device 5 through the compensation wire 4.

Referring to fig. 2, the terminal block NTAI 06201 in the control system is connected with the other end of the two cores of the compensation lead 4 in a positive-positive, negative-negative mode, and transmits an electric signal to the temperature clamping piece ASI 23203 through the connection cable NKAS 01202, the temperature clamping piece ASI 23203 converts the electric signal into a digital signal which can be identified by the controller, the temperature clamping piece ASI 23203 and the main controller BRC 400205 are inserted into a slot of the back plate MMU 22204 and communicate through the back plate, and the main controller BRC 400205 performs logic operation on the received signal through the logic module 206.

Referring to fig. 3, the logic module performs logic operation on the input temperature according to the connection mode of the modules in the diagram, the output temperature is the maximum value of the steam temperature within 10 minutes, and the reduction value of the steam temperature within 10 minutes is obtained by subtracting the input temperature from the output temperature.