CN-121993777-A - Automatic purging control method and system for differential pressure transmitter of coal-fired generator set

CN121993777ACN 121993777 ACN121993777 ACN 121993777ACN-121993777-A

Abstract

The application discloses an automatic purging control method and system for a differential pressure transmitter of a coal-fired power generating unit. According to the method, a comprehensive blocking index is set for each measuring point and used for quantitatively evaluating the current blocking risk, two dimensions of the current state and the change trend can be fused into a continuous and quantitative index, so that the system can not only recognize blocking, but also evaluate the severity and urgency of the blocking, a data basis is provided for realizing grading alarm or differential purging strategies subsequently, and therefore the blocking state can be judged automatically and intelligently, purging can be performed rapidly, and the effect can be quantitatively verified.

Inventors

KANG XU
ZHANG TIELIANG
ZHAO WENQUAN
LI ZHENFU
ZHOU YUJIAN
SUN QIAN
CHEN FANG
YANG BOWEN
LIU YING

Assignees

天津国能津能热电有限公司

Dates

Publication Date: 20260508
Application Date: 20251222

Claims (10)

1. An automatic purging control method for a differential pressure transmitter of a coal-fired power generation unit is characterized by comprising the following steps of: Step one, simultaneously collecting real-time differential pressure measured values of at least 3 adjacent measuring points in a sampling pipe of a differential pressure transmitter, and preprocessing each real-time differential pressure measured value to obtain a real-time differential pressure processed value of each measuring point; Step two, obtaining differential pressure dynamic reference values of all the measuring points according to differential pressure processing values of the measuring points, and carrying out normalization processing on the deviation degree of each measuring point according to the differential pressure processing values of each measuring point and the differential pressure dynamic reference values to obtain normalized deviation degrees of each measuring point; Step three, obtaining the comprehensive blocking index of each measuring point through the normalized deviation degree and the deviation deterioration rate of each measuring point, and judging that the measuring point is blocked and sending out a purging demand instruction when the comprehensive blocking index of a certain measuring point continuously exceeds a preset trigger threshold value and continuously lasts for a preset time period; Judging the comprehensive start-up permission condition, if the purging is started, judging whether the normalized deviation degree of the measuring point and the real-time working condition deviation coefficient of the differential pressure treatment values of all the measuring points are lower than a set threshold value or not in the purging process, if not, continuing to purge for preset time, if so, stopping the purging; step five, after stopping the purging, judging whether the normalized deviation degree of the measuring point and the real-time working condition deviation coefficient of the differential pressure treatment values of all the measuring points are lower than a set threshold value, if not, returning to the step four to continue the purging, if the accumulated purging time exceeds a preset upper limit and is not met, forcibly stopping the purging and alarming, if yes, ending the purging, and entering the step six; step six, after the purging is finished, the system self-detects whether a fault exists, if not, the system judges that the purging of the measuring point is finished and the measuring point is operated, if so, the system executes a guarantee operation aiming at the fault state and displays the fault and the measuring point state.
2. The automatic purge control method according to claim 1, wherein in the second step, the differential pressure dynamic reference values of all the measurement points are obtained by the following formula: ; Wherein, the Is a dynamic reference value of differential pressure, and is unit kPa; for the pressure difference processing value sequence of n measuring points at the time t, n is more than or equal to 3, calculate When the sequence is used, the sequence is firstly Ordered from small to large or from large to small, if n is an odd number, Is the median value of the data of n measuring points, if n is an even number, Is the average of the middle two data of the n measuring point data.
3. The automatic purge control method according to claim 2, wherein in the second step, the normalized deviation degree is obtained by the following formula: ; Wherein, the For normalized deviation, the units are, The pressure difference is a real-time pressure difference treatment value of the ith measuring point after pretreatment at the moment t, i=1, 2,3, 。
4. The automatic purge control method according to claim 3, wherein in the second step, the deviation deterioration rate of each measurement point is obtained by the following formula: ; wherein the slope of the fitting straight line is extracted as the deviation deterioration rate by performing linear regression analysis on the latest N pieces of normalized deviation data Unit%/s or%/min; N is a preset integer and is more than or equal to 2 for the latest N normalized deviation degree sequences.
5. The automatic purge control method according to claim 4, wherein in the third step, the algorithm of the integrated clogging index of each measuring point is: Wherein, the To synthesize the occlusion index, T is the total time window of the last N cycles, The weight coefficient of the deviation degree of each measuring point, Weighting and summing the deviation degree and the deviation deterioration rate according to a preset weight distribution proportion for the weight coefficient of the deviation deterioration rate of each measuring point to obtain a comprehensive blocking index; When (when) And continuing the preset time period to judge that the measuring point is blocked.
6. The automatic purge control method according to claim 3, wherein in the fourth step, a real-time operating condition deviation coefficient of the differential pressure treatment values of all the measurement points is determined The algorithm of (1) is as follows: 2 ; Wherein, the The real-time working condition deviation coefficient is the unit of kPa; Differential pressure treatment value for each measuring point Average value of (2).
7. The automatic purging control method according to claim 1, wherein the fourth step further comprises the steps of judging a status bit by the main control system before purging is started, executing a preset program, and maintaining the differential pressure value in a maintenance state, and the sixth step further comprises the steps of performing fault self-checking by the main control system and executing corresponding operations according to different conditions after purging is finished.
8. The automatic purge control method according to claim 1, further comprising: When an emergency working condition occurs, the purging process is cut off through the manual emergency stop interface, and data output of the real-time differential pressure measured values of all purged measuring points is recovered.
9. The automatic purge control method according to claim 1, wherein in the first step, each real-time differential pressure measurement value is preprocessed, and the preprocessing is that a kalman filter algorithm is adopted to process a data sequence of the real-time differential pressure measurement value of each measuring point.
10. An automatic purge system for a differential pressure transmitter of a coal-fired power generation unit, applied to the automatic purge control method according to any one of claims 1 to 9, characterized by comprising: The multipoint measurement unit comprises at least three differential pressure transmitters which are arranged at adjacent positions in the measured pipeline and are independently installed; the purging execution unit comprises a plurality of purging branch pipelines which are respectively communicated with the pressure taking pipelines of the differential pressure transmitters, wherein the purging branch pipelines are arranged to be capable of controlling on-off independently, and The central control unit is electrically connected with the multipoint measurement unit and the purging execution unit and comprises a data receiving module, a data processing module, a logic judging module and an execution control module, wherein the data receiving module is used for receiving real-time pressure difference values of all measuring points, the data processing module is used for preprocessing the real-time pressure difference values, calculating normalized deviation degree, deviation deterioration rate and comprehensive blocking index, the logic judging module is used for analyzing the processed data in real time and judging whether blocking occurs or not according to preset compound logic conditions, and the execution control module is used for automatically controlling the purging execution unit to execute purging, verifying purging effect in real time and controlling state switching and recovery of the whole flow.

Description

Automatic purging control method and system for differential pressure transmitter of coal-fired generator set Technical Field The application relates to the technical field of coal-fired power station boilers, in particular to an automatic purging control method and system for a differential pressure transmitter of a coal-fired power unit. Background In the thermal power generation process, primary air bears the important function of conveying pulverized coal into a hearth, and the accurate measurement of the air quantity of the primary air directly relates to the air distribution optimization, the combustion efficiency and the operation safety and stability of a boiler. At present, a differential pressure method is generally adopted to measure the primary air quantity, namely, a differential pressure device is arranged in a primary air duct, and a differential pressure transmitter is utilized to convert a measured differential pressure signal into a standard electric signal so as to calculate an air quantity value. The measurement result is taken as a key parameter to participate in combustion control logic, and is a basis for realizing efficient and clean combustion. In the prior art, in order to solve the problem of blockage of a pressure taking port and a pressure guiding pipeline caused by coal dust, fly ash and unburned carbon particles carried in primary air, the maintenance is mainly carried out in a periodic manual purging mode. The specific operation comprises working ticket handling, measuring point exiting, pipeline disassembling, compressed air blowing in, dust deposit cleaning, reinstallation, measuring point operation and the like. Although the method can temporarily restore the measurement function to a certain extent, the method is a passive and empirical maintenance means in nature, and the whole process is highly dependent on human intervention. However, the existing maintenance mode has a plurality of defects that firstly, the maintenance has blindness and hysteresis, the preventive purging with a fixed period cannot dynamically respond to the boiler load fluctuation and the coal quality change, the insufficient maintenance or the excessive maintenance is easy to cause, and the fault driving type purging has response hysteresis, so that the measurement distortion causes long-time interference to the control system. Secondly, the operation flow is complex and long, multiple persons are needed to cooperate and go through multiple examination and approval and operation links in a single operation, the time consumption can reach tens of minutes to several hours, and quick response and immediate processing are difficult to realize. Thirdly, the operation is practically limited, and the unit is required to be in a low-load window period. It must be ensured that the unit load-up requirement cannot be affected when the purge is completed. Fourth, the risk of misoperation is larger in the operation process, the wrong dismantling point or the wrong forced measuring point can cause sharp fluctuation of air quantity, the risk of misoperation is increased, and the reliability of the system is reduced. Fifthly, the working environment is severe, the personnel safety risk is increased due to high temperature, high dust and high noise, the sealing structure is damaged easily due to frequent disassembly and assembly, the interface thread is damaged, the leakage hidden trouble is introduced, and the long-term reliability of the system is reduced. Sixth, lack of a scientific and closed-loop effect verification mechanism, whether the purging completely depends on subjective judgment and visual inspection, cannot be quantitatively evaluated, and is easy to remain and accumulate dirt, so that the blockage problem repeatedly occurs. Therefore, a primary air quantity measuring and maintaining system capable of realizing automation, intelligence, high efficiency and effect feedback is needed in the prior art, so as to overcome the defects and improve the stability and safety of the operation of the boiler. Disclosure of Invention The application mainly aims to provide an automatic purging control method and system for a differential pressure transmitter of a coal-fired power generating unit, so that the blocking state can be automatically and intelligently judged, purging can be rapidly executed, and the effect can be quantitatively verified. According to a first aspect of the application, an automatic purging control method for a differential pressure transmitter of a coal-fired power generating unit is provided, comprising the following steps of firstly, collecting real-time differential pressure measured values of at least 3 adjacent measuring points in a sampling pipe of the differential pressure transmitter, and preprocessing each real-time differential pressure measured value to obtain a real-time differential pressure processed value of each measuring point; step two, obtaining differential pressure dynam