Monitoring method for judging working condition of thermal power generating unit in real time

Abstract

The invention discloses a monitoring method for judging the working condition of a thermal power generating unit in real time, and particularly relates to the monitoring field of the working condition of the thermal power generating unit, comprising the following steps: S1, collecting multi-dimensional operating parameters of the thermal power generating unit, and establishing a three-dimensional dynamic coordinate system; s2, constructing a parameter dynamic correlation model, and calculating a parameter coupling degree based on the residual sum of squares; s3, calculating the spatial distance between the current operating point and the original point in the operating state coordinate system, and calculating the working condition deviation degree in combination with the parameter coupling degree; s4, working condition grades are divided according to the working condition deviation degree, and real-time judgment and early warning are achieved in combination with the deviation degree change rate; s5, corresponding adjustment strategies are executed according to different working condition grades, and real-time monitoring is carried out until the working condition returns to normal; according to the method, the multi-dimensional parameters of the thermal power generating unit are collected, the parameter dynamic correlation model is constructed, and the working condition deviation degree is calculated, so that collaborative analysis among the parameters is realized, the problem of misjudgment caused by single parameter monitoring in the prior art is solved, and the working condition judgment accuracy is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of monitoring the working condition of a thermal power unit, and more particularly to a monitoring method for real-time determination of the working condition of a thermal power unit. BACKGROUND

[0002] During the operation of a thermal power unit, working condition monitoring is a key link for ensuring the safe and stable operation of the unit. Currently, key parameters are collected through the arrangement of temperature, pressure, flow and other sensors, basic data monitoring and recording are realized in combination with a DCS control system, and a static threshold model is established relying on historical operation data, so as to determine whether the unit is in a normal working condition.

[0003] The prior art can realize real-time collection and overrun alarm of core parameters of the unit, and to some extent, meets the basic monitoring requirements, but has obvious deficiencies: first, a single parameter threshold determination mode is adopted, and the correlation between parameters is ignored, for example, abnormal exhaust steam temperature of a steam turbine may be associated with condenser vacuum degree, circulating water flow and other parameters, and separate monitoring may lead to misjudgment; second, the static threshold model cannot adapt to dynamic scenarios such as unit load fluctuation and environmental temperature change, and when the unit is in variable load operation, the fixed threshold is easy to trigger invalid alarm or miss alarm; third, the working condition determination is obviously lagging, and only responds when the parameter is overrun, and cannot predict the potential working condition degradation trend in advance.

[0004] In view of the problems of insufficient parameter correlation analysis, poor dynamic adaptability and lagging early warning in the prior art, the present application provides a monitoring method for real-time determination of the working condition of a thermal power unit, which realizes collaborative analysis between parameters and early determination of working condition through the construction of a dynamic correlation model, and improves the accuracy and timeliness of monitoring. SUMMARY

[0005] In order to overcome the above-mentioned defects of the prior art, the present application provides a monitoring method for real-time determination of the working condition of a thermal power unit, which solves the problems raised in the background art through the following scheme.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a monitoring method for real-time determination of the working condition of a thermal power unit, comprising: S1, collecting multi-dimensional operation parameters of the thermal power unit, and establishing a three-dimensional dynamic coordinate system; S2, constructing a parameter dynamic correlation model, and calculating a parameter coupling degree based on residual sum of squares; S3, calculating the spatial distance between the current operating point and the origin in the operating state coordinate system, and calculating the working condition deviation degree in combination with the parameter coupling degree; S4, dividing the working condition level according to the working condition deviation degree, and realizing real-time determination and early warning in combination with the deviation degree change rate; S5, execute corresponding adjustment strategy for different working condition levels, and monitor in real time until the working condition returns to normal.

[0007] Preferably, the multi-dimensional operating parameters specifically include main steam temperature T, main steam pressure P, turbine speed N, condenser vacuum V, boiler feed water flow F, and furnace outlet flue gas temperature Y; the three-dimensional dynamic coordinate system takes the operating state at rated load of the unit as the origin, takes the main steam flow rate of change as the x-axis, takes the turbine speed deviation rate as the y-axis, and takes the unit load fluctuation as the z-axis, thereby constructing the three-dimensional dynamic coordinate system.

[0008] Preferably, the parameter dynamic correlation model includes a temperature-pressure correlation model, a speed-current correlation model, and a vacuum-flow correlation model; the temperature-pressure correlation model is used to perform nonlinear fitting on the main steam temperature T and the main steam pressure P to obtain a theoretical pressure value calculated based on temperature , wherein represents a temperature-pressure coupling coefficient, represents a reference correction value; the speed-current correlation model is used to perform correlation analysis on the turbine speed N and the generator stator current I to obtain a theoretical current value calculated based on speed , wherein represents an electromechanical conversion coefficient, represents a loss correction value; and the vacuum-flow correlation model is used to perform coupled calculation on the condenser vacuum V and the boiler feed water flow F to obtain a theoretical vacuum degree calculated based on flow , wherein represents a vacuum-flow coefficient, represents an environmental correction value; the parameter coupling degree is used to extract the residual sum of squares of the actual collection value and the theoretical calculation value of each parameter, denoted as Q1, Q2, and Q3, respectively, and specifically represented as: parameter coupling degree .

[0009] Preferably, the specific way of calculating the working condition deviation degree is: in the operating state coordinate system, the current operating point coordinates (x, y, z) are obtained, the spatial distance between the current operating point and the origin is calculated , and the working condition deviation degree is calculated in combination with the parameter coupling degree C .

[0010] Preferably, the working condition deviation degree includes an initial threshold value and a serious deviation working condition threshold value ; the working condition level: when S < 0.5, it is determined as normal working condition; when 0.5 ≤ S < 1, it is determined as slightly deviated working condition; and when S ≥ 1, it is determined as serious deviated working condition. ​​​When the deviation degree is greater than 0 and the duration exceeds the early warning delay threshold, an early warning mechanism is triggered.

[0011] Preferably, the adjustment strategy specifically comprises: when it is determined that the working condition is slightly deviated, adjusting the swing angle of the boiler burner wherein represents a swing angle correction coefficient, represents a main steam rated temperature; when it is determined that the working condition is seriously deviated, firstly reducing the unit load wherein represents a load adjustment coefficient, represents a rated rotating speed, and simultaneously starting a standby cooling system to adjust the cooling water amount wherein represents a water amount correction coefficient, represents a rated vacuum degree; in the adjustment process, parameters are collected in real time and the working condition deviation degree is recalculated until S adjustment is stopped.

[0012] Technical effects and advantages of the present application: 1. The present application realizes the collaborative analysis among parameters by collecting multi-dimensional parameters of the thermal power unit, constructing a parameter dynamic correlation model and calculating the working condition deviation degree, solves the misjudgment problem caused by single parameter monitoring in the prior art, and improves the accuracy of working condition judgment. 2. The present application calculates the working condition deviation degree based on the operation state coordinate system and the parameter coupling degree, realizes dynamic early warning in combination with the deviation degree change rate, solves the poor adaptability problem of the static threshold model, can accurately identify working condition abnormalities in dynamic scenes such as variable load, and improves the real-time and forward nature of monitoring. 3. The present application formulates a targeted adjustment strategy according to the working condition level, realizes the dynamic optimization of the unit through quantitative parameter correction, solves the hysteresis problem of the traditional adjustment, reduces the unit fault risk, and improves the operation economy. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a schematic diagram of the overall structure of the present application. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0015] As shown in the accompanying Figure 1The embodiment of the application discloses a real-time monitoring method for judging the working condition of a thermal power generating unit S1, collecting multi-dimensional operation parameters of the thermal power generating unit, and establishing a three-dimensional dynamic coordinate system; It should be particularly noted that the multi-dimensional operation parameters specifically include a main steam temperature T, a main steam pressure P, a steam turbine rotating speed N, a condenser vacuum V, a boiler feed water flow F and a furnace outlet flue gas temperature Y; the three-dimensional dynamic coordinate system takes the operation state of the unit at the rated load as an origin, takes a main steam flow rate change rate as an x axis, takes a steam turbine rotating speed deviation rate as a y axis, and takes a unit load fluctuation as a z axis, so that the three-dimensional dynamic coordinate system is constructed. The safe and stable operation of the thermal power generating unit depends on the cooperative balance of multiple parameters, the parameters collected in the scheme are all core indexes reflecting the operation state of the unit, and there is a clear physical correlation between the parameters, and the specific physical correlation is as follows: the main steam temperature T and the pressure P: the two are core indexes of the steam energy output by the boiler, meet the steam thermodynamic characteristics (temperature rise will cause nonlinear change of pressure), and are key parameters reflecting the combustion efficiency of the boiler; the steam turbine rotating speed N and the generator stator current I: the rotating speed directly determines the power generation frequency, and the current reflects the actual output power, and the two follow a "rotating speed-power" dynamic correlation law (rotating speed change will cause current fluctuation according to a specific function relationship); the condenser vacuum V and the boiler feed water flow F: the vacuum degree affects the steam turbine exhaust efficiency, and the feed water flow determines the boiler heat exchange efficiency, and the two form a coupling relationship through "steam-water circulation" (change of the feed water flow will change the condenser heat load, and then affect the vacuum degree); the furnace outlet flue gas temperature Y: directly reflects the combustion state of the boiler (combustion sufficiency, flame center position and the like), and is a "central index" related to all the above parameters. The selection of the above parameters covers core equipment such as the boiler, the steam turbine and the generator, and embodies the physical coupling relationship between the parameters, thereby providing a solid physical basis for subsequent model construction.

[0016] S2, constructing a parameter dynamic correlation model, and calculating a parameter coupling degree based on a residual sum of squares; It should be particularly noted that the parameter dynamic correlation model includes a temperature-pressure correlation model, a rotating speed-current correlation model and a vacuum-flow correlation model; the temperature-pressure correlation model is used for nonlinear fitting of the main steam temperature T and the main steam pressure P, to obtain a theoretical pressure value calculated based on the temperature , wherein represents a temperature-pressure coupling coefficient, represents a reference correction value; the rotating speed-current correlation model is used for correlation analysis of the steam turbine rotating speed N and the generator stator current I, to obtain a theoretical current value calculated based on the rotating speed , wherein represents an electromechanical conversion coefficient, represents a loss correction value; the vacuum-flow correlation model is used to couple the condenser vacuum V and the boiler feed water flow F to obtain a theoretical vacuum degree based on flow calculation , wherein represents a vacuum flow coefficient, represents an environmental correction value; the parameter coupling degree is used to extract the residual sum of squares of the actual acquisition value and the theoretical calculation value of each parameter, respectively denoted as Q1, Q2 and Q3, and specifically represented as: parameter coupling degree .

[0017] S3, calculate the spatial distance between the current operating point and the origin in the operating state coordinate system, and calculate the operating condition deviation degree combined with the parameter coupling degree; Specifically, the method for calculating the operating condition deviation degree is as follows: in the operating state coordinate system, the current operating point coordinates (x, y, z) are obtained, the spatial distance between the current operating point and the origin is calculated , and the operating condition deviation degree is calculated combined with the parameter coupling degree C .

[0018] S4, divide the operating condition level according to the operating condition deviation degree, and realize real-time judgment and early warning combined with the deviation degree change rate; Specifically, the operating condition deviation degree includes an initial threshold and a serious deviation condition threshold ; the operating condition level: when S , it is determined that the operating condition is normal; when ≤S , it is determined that the operating condition is slightly deviated; when S≥ , it is determined that the operating condition is seriously deviated; when the deviation degree change rate is greater than 0 and the duration exceeds the warning delay threshold, the warning mechanism is triggered.

[0019] S5, execute corresponding adjustment strategies for different operating condition levels, and real-time monitor until the operating condition returns to normal.

[0020] Specifically, the adjustment strategy specifically includes: when it is determined that the operating condition is slightly deviated, adjust the swing angle of the boiler burner , wherein represents a swing angle correction coefficient, represents the rated temperature of the main steam; when it is determined that the operating condition is seriously deviated, first reduce the unit load , wherein represents a load adjustment coefficient, represents the rated speed, and simultaneously start the standby cooling system to adjust the cooling water quantity , wherein represents a water quantity correction coefficient, Indicates the rated vacuum degree; real-time acquisition of parameters during adjustment and recalculation of working condition deviation until S < S1

[0021] Wherein, the design of working condition deviation combines the dual dimensions of "spatial deviation" and "parameter coupling": the spatial distance quantifies the physical deviation of the current state of the unit from the rated state through a three-dimensional coordinate system, meeting the demand for "multi-dimensional parameter collaborative evaluation"; the parameter coupling degree C: reflects the synergy between parameters through the reciprocal product of residuals (the smaller the residual, the higher the coupling degree), introduces the influence of the furnace outlet flue gas temperature Y on the overall coupling of the corrected combustion state, and ensures that the coupling degree can truly reflect the comprehensive state of the unit; the exponential term is used to amplify the cumulative effect of parameter fluctuations (when x, y and z deviate in the same direction, the exponential term rapidly increases, strengthening the sensitivity of the deviation), avoiding the lag of early warning caused by the accumulation of small deviations, and meeting the evolution law of "small deviation-big fault" of the unit. The adjustment strategies formulated in the scheme according to the working condition level are all conventional and effective control means in the operation of thermal power units, as follows: adjusting the boiler burner swing angle under slight deviation working condition: the burner swing angle directly affects the flame center position, and then adjusts the main steam temperature T (the swing angle upward can increase the furnace outlet flue gas temperature and increase the steam heat absorption), the adjustment amount is linked with the deviation and the temperature deviation rate, realizing "quantitative adjustment" and avoiding the blindness of traditional empirical operation; reducing the load and adjusting the cooling water under serious deviation working condition: reducing the load is a basic safety measure when the unit appears serious abnormality (reducing energy input to reduce equipment pressure), adjusting the cooling water can quickly improve the condenser vacuum (increasing cooling can improve the vacuum and improve the steam turbine efficiency), the adjustment amount of both is directly related to the deviation, ensuring that the adjustment intensity matches the abnormality degree; closed-loop adjustment mechanism (real-time calculation of S until S < S1): conforms to the classic closed-loop logic of "monitoring-judgment-adjustment-remonitoring" in industrial control, ensuring that the adjustment effect is verifiable and traceable, and avoiding the problem of one-time adjustment not in place.

[0022] The present application realizes collaborative analysis between parameters by collecting multi-dimensional parameters of thermal power units, constructing a parameter dynamic correlation model and calculating working condition deviation, solves the misjudgment problem caused by single parameter monitoring in the prior art, and improves the accuracy of working condition judgment; based on the operation state coordinate system and the parameter coupling degree, the working condition deviation is calculated, and dynamic early warning is realized by combining the deviation change rate, solving the poor adaptability problem of the static threshold model, accurately identifying the working condition abnormality in dynamic scenes such as variable load, and improving the real-time and forwardness of monitoring; according to the working condition level, the specific adjustment strategy is formulated, the dynamic optimization of the unit is realized through quantitative parameter correction, the traditional adjustment lag problem is solved, the unit fault risk is reduced, and the operation economy is improved.

[0023] ​Secondly: the embodiment of the present application discloses only the structure related to the embodiment of the present application, other structures can refer to the general design, and in the case of no conflict, the same embodiment and different embodiments of the present application can be combined with each other; Finally: the above only describes the preferred embodiments of the present application and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A monitoring method for judging the working condition of a thermal power generating unit in real time, characterized in that, include: S1. Collect multi-dimensional operating parameters of thermal power units and establish a three-dimensional dynamic coordinate system; S2. Construct a dynamic parameter correlation model and calculate the parameter coupling degree based on the sum of squared residuals; S3. Calculate the spatial distance between the current running point and the origin in the running state coordinate system, and calculate the working condition deviation in combination with the parameter coupling degree; S4. Divide the working condition level according to the deviation of the working condition, and realize real-time judgment and early warning by combining the deviation change rate; S5. Implement corresponding adjustment strategies for different operating condition levels and monitor in real time until the operating condition returns to normal.

2. The monitoring method for judging the working condition of a thermal power generating unit in real time according to claim 1, characterized in that: The multi-dimensional operating parameters specifically include main steam temperature T, main steam pressure P, turbine speed N, condenser vacuum V, boiler feedwater flow rate F, and furnace outlet flue gas temperature Y; the three-dimensional dynamic coordinate system is constructed with the unit's rated load operating state as the origin, the main steam flow rate change rate as the x-axis, the turbine speed deviation rate as the y-axis, and the unit load fluctuation as the z-axis.

3. The monitoring method for real-time judgment of the operating condition of thermal power units according to claim 1, characterized in that: The parameter dynamic correlation models include a temperature-pressure correlation model, a speed-current correlation model, and a vacuum-flow correlation model; the temperature-pressure correlation model is used to perform nonlinear fitting between the main steam temperature T and the main steam pressure P to obtain the theoretical pressure value calculated based on the temperature. ,in Indicates the temperature-pressure coupling coefficient. This represents the baseline correction value; the speed-current correlation model is used to perform correlation analysis between the turbine speed N and the generator stator current I to obtain the theoretical current value calculated based on the speed. ,in Indicates the electromechanical conversion factor. This represents the loss correction value; the vacuum-flow correlation model is used to couple the condenser vacuum degree V with the boiler feedwater flow rate F to obtain the theoretical vacuum degree based on flow rate calculation. ,in Indicates the vacuum flow coefficient. The environmental correction value is represented; the parameter coupling degree is used to extract the sum of squared residuals between the actual collected values ​​and the theoretical calculated values ​​of each parameter, denoted as Q1, Q2, and Q3 respectively, and is specifically expressed as: parameter coupling degree. .

4. The monitoring method for real-time judgment of the operating condition of thermal power units according to claim 2, characterized in that: The specific method for calculating the deviation of the operating condition is as follows: In the operating state coordinate system, obtain the coordinates (x, y, z) of the current operating point, and calculate the spatial distance between the current operating point and the origin. The deviation of the operating condition is calculated by combining the parameter coupling degree C. .

5. The monitoring method for real-time judgment of the operating condition of a thermal power unit according to claim 2, characterized in that: The deviation from the operating condition includes an initial threshold. and serious deviation from the operating condition threshold The operating condition level is: when S < When, it is determined to be a normal operating condition; when ≤S< When S ≥ 0, it is judged as a slight deviation from the operating condition; when S ≥ 0. When the deviation rate is greater than 0 and the duration exceeds the warning delay threshold, the warning mechanism is triggered.

6. The monitoring method for real-time judgment of the operating condition of a thermal power unit according to claim 2, characterized in that: The adjustment strategy specifically includes: adjusting the boiler burner sway angle when a slight deviation from the operating condition is detected. ,in This represents the swing angle correction factor. This indicates the rated temperature of the main steam; when it is determined to be a serious deviation from the operating condition, the unit load should be reduced first. ,in Indicates the load adjustment factor. Indicates the rated speed, simultaneously activates the backup cooling system, and adjusts the coolant flow rate. ,in This represents the water quantity correction factor. This indicates the rated vacuum level; during the adjustment process, parameters are collected in real time and the deviation from the operating condition is recalculated until S < Stop adjusting when the time is right.

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