Search

CN-121976861-A - Self-adaptive water spraying temperature reduction system based on low-pressure final stage blasting temperature of steam turbine

CN121976861ACN 121976861 ACN121976861 ACN 121976861ACN-121976861-A

Abstract

The invention discloses a self-adaptive water spraying temperature reduction system based on low-pressure final stage blast temperature of a steam turbine, which relates to the field of steam turbine temperature reduction and comprises a multipoint blast temperature monitoring module, a load-temperature linkage self-adaptive control module, a high-precision water spraying execution module and a safety protection and early warning module which are connected with the load-temperature linkage self-adaptive control module in a signal mode. In the invention, 3 groups of high-precision thermocouples are respectively arranged at the front and the steam exhaust ports of the low-pressure final stage of the steam turbine, a PID+load pre-judging composite model is adopted, parameters such as the current load, the change rate and the like of the unit are input, future load is predicted by an exponential smoothing method, the air blast temperature is pre-judged by combining a load-temperature correlation matrix, the deviation is controlled in a smaller range after calibration, and the pre-judging window can be dynamically adjusted. And calculating the water spraying amount based on a thermodynamic equilibrium formula, self-correcting, presetting in advance to avoid the temperature exceeding a 180 ℃ threshold value, and perfectly adapting to a steam extraction energy storage low-load fluctuation scene.

Inventors

  • ZHANG XIAOXU
  • LI XIANG
  • ZHAO GUANGYAO
  • DUAN LIBO

Assignees

  • 国能河北龙山发电有限责任公司

Dates

Publication Date
20260505
Application Date
20251216

Claims (10)

  1. 1. The self-adaptive water spraying and temperature reducing system based on the low-pressure final stage blast temperature of the steam turbine is characterized by comprising a multipoint blast temperature monitoring module, a load-temperature linkage self-adaptive control module, a high-precision water spraying execution module and a safety protection and early warning module which are connected in sequence in a signal mode, wherein the high-precision water spraying execution module is connected with the load-temperature linkage self-adaptive control module in a signal mode; The multi-point blast temperature monitoring module collects and transmits temperature signals related to low-pressure final stage blast of the steam turbine, the load-temperature linkage adaptive control module adopts a PID+load pre-judging composite model, pre-judges blast temperature and calculates water spraying amount based on real-time signals, unit operation parameters and historical data, and outputs an adjusting instruction, the high-precision water spraying execution module executes water spraying amount adjustment and adapts load fluctuation, the safety protection and early warning module triggers over-temperature interlocking and water erosion early warning, and the core control target of the system is that the temperature before the low-pressure final stage is less than or equal to 180 ℃ and the exhaust temperature is less than or equal to 70 ℃ and adapts to the extraction and energy storage low-load heat storage working condition of the thermal power unit.
  2. 2. The self-adaptive water spraying temperature reduction system based on the low-pressure final stage blast temperature of the steam turbine according to claim 1, wherein the multi-point blast temperature monitoring module is respectively and uniformly provided with 3 groups of thermocouples at the front of the low-pressure final stage of the steam turbine and at the exhaust port of the low-pressure cylinder, the measuring range of the thermocouples is-20-400 ℃ and the precision is +/-0.5 ℃, and temperature signals are transmitted at the sampling frequency of 1Hz through a high-temperature resistant shielded cable to cover the peripheral critical area of the final stage blade.
  3. 3. The self-adaptive water spray temperature reducing system based on the low-pressure final stage blasting temperature of the steam turbine according to claim 1, wherein the PID+load pre-judging composite model input parameters of the load-temperature linkage self-adaptive control module comprise the current load of a unit acquired by 1Hz AGC load command Current low pressure final stage front temperature Load change rate for 1Hz differential calculation And a load-temperature correlation matrix trained offline and updated every 1 hour.
  4. 4. The self-adaptive water spray temperature reduction system based on the low-pressure final stage blast temperature of the steam turbine according to claim 3, wherein the pre-judging logic of the PID+load pre-judging composite model is that short-term load pre-judging adopts an exponential smoothing method, and the formula is as follows: ; Initial value ; Temperature trend prejudgment establishes a mapping model based on the incidence matrix: ; And calibrated by the following formula: ; Prejudging window Default 5min, and dynamic adjustment to 3-10 min according to the temperature increase and the load change rate.
  5. 5. The self-adaptive water spray temperature reducing system based on low-pressure final stage blasting temperature of steam turbine according to claim 1, wherein the load-temperature linkage self-adaptive control module calculates the water spray amount through a thermodynamic equilibrium model The formula is as follows: ; Wherein the method comprises the steps of In order to correct the coefficient of the coefficient, For the low pressure cylinder steam flow, self-correcting based on historical data, Corresponding to the low-pressure final stage front temperature or the exhaust temperature, Corresponding to 180 ℃ or 70 ℃.
  6. 6. The self-adaptive water spray temperature reducing system based on the low-pressure final stage blast temperature of the steam turbine according to claim 1, wherein an actuating mechanism in the high-precision water spray actuating module adopts a main path and a bypass double-path pipeline structure, the main path bears 70% rated water spray quantity adjustment, and the bypass is adapted to small flow supplement.
  7. 7. The self-adaptive water spraying and temperature reducing system based on the low-pressure final stage blasting temperature of the steam turbine according to claim 1, wherein the overtemperature interlocking function of the safety protection and early warning module triggers emergency water spraying and sends an alarm signal to the DCS when the temperature before the low-pressure final stage is more than 180 ℃ or the exhaust steam temperature is more than 80 ℃, and the steam extraction quantity is reduced in a linkage way; And when the water spray quantity is 90% of the design value and lasts for 10min or the opening of the regulating valve is 95%, the water erosion early warning function gives out early warning and recommends optimizing the back pressure of the unit to be below 7 kPa.
  8. 8. The self-adaptive water spraying and temperature reducing system based on the low-pressure final stage blast temperature of the steam turbine according to claim 6, wherein the executing mechanism comprises an end cover (1), a spray pipe (2) and a spray nozzle (6), the tip end of the spray pipe (2) is in threaded connection with the spray nozzle (6), a main pipe (5) and a bypass pipe (8) are arranged at the other end of the spray pipe (2), a primary through groove (13) is formed in the middle line position of the spray pipe (2), a primary main passage (9) is formed in the spray pipe (2) and located on the outer side of the primary through groove (13), the middle passage of the main pipe (5) is communicated with the primary main passage (9), and the bypass pipe (8) is communicated with the primary through groove (13).
  9. 9. The self-adaptive water spray temperature reducing system based on the low-pressure final stage blast temperature of the steam turbine is characterized in that a secondary through groove (15) is formed in the center line position of the nozzle (6), a secondary main passage (14) is formed in the nozzle (6) and located outside the secondary through groove (15), the primary main passage (9) is communicated with the secondary main passage (14), the secondary through groove (15) is communicated with the primary through groove (13), a pin (16) is slidingly arranged in an inner gap of the secondary through groove (15), a middle shaft (10) is slidingly inserted at the upper end of the pin (16), the middle shaft (10) is slidingly arranged in the primary through groove (13), a spring (11) is abutted to the other end of the middle shaft (10), a push rod (12) is abutted to the other end of the spring (11), a bolt (7) is inserted at the other end of the push rod (12), and the bolt (7) is in threaded connection with the middle part of the end cover (1).
  10. 10. The self-adaptive water spraying and temperature reducing system based on the low-pressure final stage blast temperature of the steam turbine, as set forth in claim 9, is characterized in that the end cover (1) is in threaded connection with the end part of the spray pipe (2), the outer side of the bypass pipe (8) is in threaded connection with the bypass connecting pipe (3), the outer side of the main pipe (5) is in threaded connection with the main connecting pipe (4), and the bypass connecting pipe (3) and the main connecting pipe (4) are connected with a water source through electromagnetic valves.

Description

Self-adaptive water spraying temperature reduction system based on low-pressure final stage blasting temperature of steam turbine Technical Field The invention relates to the technical field of steam turbine temperature reduction, in particular to a self-adaptive water spraying temperature reduction system based on low-pressure final-stage blast temperature of a steam turbine. Background Under the low-load heat storage working condition of 'steam extraction energy storage' fused salt heat storage transformation of the thermal power generating unit, the low-pressure cylinder of the steam turbine is greatly reduced due to the volume flow, and the final-stage blades easily enter the blasting working condition (for example, the blasting temperature of the low-pressure final-stage outlet under the working condition of 30MW can reach 166.45 ℃), so that the steam discharge temperature exceeds 80 ℃ alarm value. However, the existing water spraying and temperature reducing system adopts a stop valve to control, and can only be fully opened/closed (the water spraying amount is 22.32t/h in a single-cylinder design), so that two main core problems exist, namely, the water spraying amount cannot be dynamically regulated according to the blast temperature, water erosion of a tail blade is easily aggravated due to excessive water spraying, the exhaust steam is overtemperature due to insufficient water spraying, and in low-load heat storage (4-hour peak regulation period), the exhaust steam temperature is fast fluctuated along with load (the 69MW working condition starts approaching an alarm value), and the safety risk is easily caused by manual regulation lag. Disclosure of Invention The invention aims to provide a self-adaptive water spraying temperature reduction system based on the low-pressure final stage blasting temperature of a steam turbine so as to solve the problems of the background art. The self-adaptive water spraying and temperature reducing system based on the low-pressure final stage blasting temperature of the steam turbine comprises a multipoint blasting temperature monitoring module, a load-temperature linkage self-adaptive control module, a high-precision water spraying execution module and a safety protection and early warning module which are connected with the load-temperature linkage self-adaptive control module in a signal way, wherein the multipoint blasting temperature monitoring module, the load-temperature linkage self-adaptive control module and the high-precision water spraying execution module and the safety protection and early warning module are connected with each other in sequence in a signal way; The multi-point blast temperature monitoring module collects and transmits temperature signals related to low-pressure final stage blast of the steam turbine, the load-temperature linkage adaptive control module adopts a PID+load pre-judging composite model, pre-judges blast temperature and calculates water spraying amount based on real-time signals, unit operation parameters and historical data, and outputs an adjusting instruction, the high-precision water spraying execution module executes water spraying amount adjustment and adapts load fluctuation, the safety protection and early warning module triggers over-temperature interlocking and water erosion early warning, and the core control target of the system is that the temperature before the low-pressure final stage is less than or equal to 180 ℃ and the exhaust temperature is less than or equal to 70 ℃ and adapts to the extraction and energy storage low-load heat storage working condition of the thermal power unit. Preferably, 3 groups of thermocouples are uniformly arranged at the front of the low-pressure final stage of the steam turbine and at the steam exhaust port of the low-pressure cylinder respectively, the measuring range of the thermocouples is-20-400 ℃ and the precision is +/-0.5 ℃, temperature signals are transmitted at the sampling frequency of 1Hz through a high-temperature resistant shielded cable, and the peripheral critical area of the final stage blade is covered. Preferably, the PID+load pre-judging composite model input parameters of the load-temperature linkage adaptive control module comprise the current load of the unit acquired by 1HzAGC load commandCurrent low pressure final stage front temperatureLoad change rate for 1Hz differential calculationAnd a load-temperature correlation matrix trained offline and updated every 1 hour. Preferably, the pre-judging logic of the PID+load pre-judging composite model is that short-term load pre-judging adopts an exponential smoothing method, and the formula is as follows: ; Initial value ; Temperature trend prejudgment establishes a mapping model based on the incidence matrix: ; And calibrated by the following formula: ; Prejudging window Default 5min, and dynamic adjustment to 3-10 min according to the temperature increase and the load change rate. Preferably, the load-temper