CN103150413A - Determining method and device for RB (Runback) project parameters in power system - Google Patents

Abstract

The invention provides a determining method and device for RB (Runback) project parameters in a power system. The method comprises the following steps of: establishing dynamic characteristics among main parameters of a unit corresponding to an RB project according to a main parameter disturbance test; establishing a system simulation model corresponding to the RB project according to actual work; performing RB project simulation test in the system simulation model according to the dynamic characteristics among main parameters; and determining the RB project parameters according to an RB project simulation test result. Through the invention, the success rate and stability of the actual RB test can be improved.

Description

Method and device for determining RB project parameters in power system

technical field

The present invention relates to a power system, in particular to a method and device for determining RB project parameters in the power system. the

Background technique

When a thermal power unit trips due to a failure of an important auxiliary machine, it loses part of its load capacity instantly, and it is a severe challenge for the rapid response and stable operation of the unit control. The design purpose of the rapid load reduction function (RUNBACK, hereinafter referred to as RB) of the unit is to ensure that under the rapid transient working condition when the main auxiliary machine of the unit fails, through logical judgment and control strategies under various working conditions and operating modes The selection can automatically reduce the load of the unit to the target load corresponding to the allowable output of the current operating equipment, and at the same time ensure that the main regulation system works normally and maintain the main parameters of the unit within the allowable range. The design of RB function of large thermal power unit is an automatic decision-making and control system project with high adaptability to working conditions and perfect automatic function. The RB test is one of the most important tests after commissioning or overhaul of the power plant unit. The one-time success rate and effective investment of the test items are of decisive significance for ensuring the safe operation of the unit and reducing the number of unplanned outages of the unit. Safety and grid-side supply security both play a pivotal role. the

However, although the existing RB test program design provides the technical process and principles to realize the RB function of the unit, it does not test and evaluate the characteristics of the unit when the actual RB occurs. When the RB test is carried out with the same type of equipment, the same working conditions, and the same RB control logic, the test results are inconsistent. For example, 4 sets of 600MW drum boilers of the same type in a certain factory were subjected to RB test after overhaul. Among them, the RB test of unit 1 was successful at one time, and the design logic of unit 2, 3 and 4 could be In the case of complete consistency, some projects cannot be successful at one time, and some even fail many times and the projects are different. This is because the characteristics of the same type of unit will not be completely consistent. In the case of consistent RB process design, the key to determining whether RB is successful depends on the main parameters of the unit such as the rate of change of coal volume, the rate of change of main steam pressure, the target value of sliding pressure, Specific setting of dynamic analog quantities such as coal reduction target value, limit value and limit rate of important auxiliary machines. The existing scheme does not provide and involve the setting method and setting basis of the above-mentioned key parameters. The setting of the above-mentioned important parameters is completely based on the experience of the test personnel, thus causing the inconsistency of the test results and the uncertainty of the success rate of the test. This increases the risk of the test and is not conducive to the safe and stable operation of the power plant. the

Contents of the invention

The main purpose of the embodiments of the present invention is to provide a method and device for determining RB project parameters in a power system, so as to solve the unstable RB test success rate caused by the RB test parameters in the prior art because the RB project parameters are only set based on empirical values The problem. the

In order to achieve the above object, the embodiment of the present invention provides a method for determining the parameters of the RB project in the power system. The method includes: establishing the dynamic characteristics between the main parameters of the unit corresponding to the RB project according to the main parameter disturbance test; establishing the dynamic characteristics according to the actual working system The system simulation model corresponding to the RB project; the RB project simulation test is carried out in the system simulation model according to the dynamic characteristics among the main parameters of the unit; the RB project parameters are determined according to the RB project simulation test results. the

Before establishing the dynamic characteristics between the main parameters of the unit corresponding to the RB item according to the main parameter disturbance test, the method further includes: obtaining the dynamic characteristics between the single mill tripping and the main parameters of the unit according to the single mill tripping disturbance test. the

Specifically, the above RB items include at least one of the following: feed water pump RB, boiler water pump RB, coal mill RB, air preheater RB, primary fan RB, and draft fan RB. the

When the above-mentioned RB item is a primary fan RB, the main parameters of the unit include: unit load, main steam pressure, coal quantity, and turbine regulating valve; the parameters of the RB item include: sliding pressure target and sliding pressure rate. the

The establishment of the dynamic characteristics between the main parameters of the unit corresponding to the RB project according to the main parameter disturbance test includes: obtaining the dynamic characteristics of the main steam pressure and unit load under different loads of the boiler according to the coal quantity disturbance test; Main steam pressure and unit load dynamic characteristics. the

When the above-mentioned RB item is the feedwater pump RB, the main parameters of the unit include: water volume, drum water level, and steam volume; the RB item parameters include: the maximum value of the feedwater pump scoop tube and the maximum speed of the feedwater pump scoop tube. the

The establishment of the dynamic characteristics between the main parameters of the unit corresponding to the RB project according to the main parameter disturbance test includes: obtaining the dynamic characteristics of the steam drum water level under the steam volume disturbance according to the steam volume disturbance test; obtaining the steam drum under the spoon tube disturbance according to the spoon tube disturbance test. Water level dynamics. the

The embodiment of the present invention also provides a device for determining the parameters of the RB project in the power system, the device includes: a main parameter dynamic characteristic establishment unit, which is used to establish the dynamic characteristics between the main parameters of the unit corresponding to the RB project according to the main parameter disturbance test The system simulation model establishment unit is used to establish the system simulation model corresponding to the RB project according to the actual working system; the simulation test execution unit is used to carry out in the system simulation model according to the dynamic characteristics between the main parameters of the unit The RB project simulation test; the RB project parameter determination unit, configured to determine the RB project parameters according to the RB project simulation test results. the

The above-mentioned device also includes: a single-mill trip-main parameter dynamic characteristic acquisition unit, which acquires the dynamic characteristics between the single-mill trip and the main parameters of the unit according to the single-mill trip disturbance test. the

The RB project simulation test performed by the above simulation test execution unit includes at least one of the following: feed water pump RB simulation test, boiler water pump RB simulation test, coal mill RB simulation test, air preheater RB simulation test, primary fan RB simulation test, delivery RB simulation test of induced draft fan. the

When the simulation test execution unit performs a fan RB simulation test, the main parameters of the unit include: unit load, main steam pressure, coal quantity, and gas turbine regulating valve; the RB project parameters include: sliding pressure target and sliding pressure rate . the

The above-mentioned main parameter dynamic characteristic establishment unit includes: the first main parameter dynamic characteristic establishment module, which is used to obtain the main steam pressure and unit load dynamic characteristics under different loads of the boiler according to the coal quantity disturbance test; the second main parameter dynamic characteristic establishment module, which is used for According to the valve disturbance test, the dynamic characteristics of main steam pressure and unit load under different boiler loads are obtained. the

When the simulation test execution unit performs the RB simulation test of the feedwater pump, the main parameters of the unit include: water volume, drum water level, and steam volume; the RB project parameters include: the maximum value of the feedwater pump scoop tube and the maximum speed of the feedwater pump scoop tube . the

The above-mentioned main parameter dynamic characteristic establishment unit includes: the third main parameter dynamic characteristic establishment module, which is used to obtain the steam drum water level dynamic characteristic under the steam quantity disturbance according to the steam quantity disturbance test; the fourth main parameter dynamic characteristic establishment module, which is used to obtain the water level dynamic characteristic according to the spoon tube The disturbance test obtained the dynamic characteristics of the water level of the steam drum under the disturbance of the spoon tube. the

With the help of at least one of the above distinguishing technical features, by first establishing the dynamic characteristics between the RB item and the main parameters, then conducting the RB simulation test, and then determining the RB item parameters according to the simulation test results, the success rate and the actual RB test can be improved. stability. the

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only of the present invention. For some embodiments, those of ordinary skill in the art can also obtain other drawings based on these drawings without paying creative efforts. the

Fig. 1 is the flow chart of the RB project parameter determination method in the power system according to the embodiment of the present invention;

Figure 2 is the load and pressure dynamic characteristic curve of the coal disturbance test directly derived from the DCS system;

Figure 3 is the trend diagram of the pressure load characteristics of the coal quantity disturbance simulated in Matlab. the

Fig. 4 is a schematic diagram of a fan RB test simulation model system according to an embodiment of the present invention;

Figure 5 is a trend diagram of the dynamic changes of the RB test simulation model simulating the actual test;

Figure 6 is a new primary wind RB test action trend diagram;

Figure 7 is a schematic diagram of the simulation model system for the control scheme of the steam and water dynamic characteristics when simulating RB;

Fig. 8 (a) is the change trend diagram of the water level in the water level setting value disturbance test when the load is constant;

Figure 8(b) is a trend diagram of the dynamic characteristics of the drum water level when the load is normally changed;

Figure 9 is a transient change trend diagram of the main steam flow rate and the drum water level when the simulated feedwater RB occurs;

Figure 10 is a real-time trend analysis diagram of the dynamic change of steam and water in the actual feed water pump RB test after adopting the newly set parameters;

Figure 11 is the action trend diagram of the RB simulation test of the feedwater pump after adopting the newly set parameters;

Fig. 12 is a structural block diagram of a device for determining parameters of RB items in an electric power system according to an embodiment of the present invention;

Fig. 13 is a specific structural block diagram of the RB project parameter determination device in the power system according to an embodiment of the present invention;

Fig. 14 is a structural block diagram of the main parameter dynamic characteristic establishing unit 1 according to an embodiment of the present invention;

Fig. 15 is a specific structural block diagram of the main parameter dynamic characteristic establishing unit 1 according to an embodiment of the present invention. the

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. the

Since there is no scientific setting method and setting basis for the RB project parameters in the existing scheme, they are only set based on the experience of the testers themselves, thus causing inconsistency in the RB test results and uncertainty in the success rate, resulting in The potential safety hazards of the power plant have been solved. Based on this, embodiments of the present invention provide a method and device for determining parameters of RB projects in a power system. The present invention will be described in detail below in conjunction with the accompanying drawings. the

Embodiment one

The embodiment of the present invention provides a method for determining RB project parameters in a power system, and Fig. 1 is a flow chart of the method, as shown in Fig. 1, the method includes:

Step 101, establish the dynamic characteristics between the main parameters of the unit corresponding to the RB project according to the main parameter disturbance test;

Step 102, establish a system simulation model corresponding to the RB project according to the actual working system;

Step 103, according to the dynamic characteristics between the main parameters of the unit, carry out the RB project simulation test in the system simulation model;

Step 104, determine the RB item parameters according to the RB item simulation test results. the

It can be seen from the above description that by first establishing the dynamic characteristics between the RB item and the main parameters, and then conducting the RB simulation test, and then determining the RB item parameters according to the simulation test results, the RB item parameters determined by modeling are compared with the actual With the experience value in the technology, the success rate and stability of the actual RB test are better improved. the

Before establishing the dynamic characteristics between the main parameters of the unit corresponding to the RB item according to the main parameter disturbance test, the above method further includes: obtaining the dynamic characteristics between the single mill trip and the main parameters of the unit according to the single mill trip disturbance test. Through the single mill tripping disturbance test, the analysis basis for the changes of each main parameter in the RB test can be improved. the

In specific implementation, the RB project includes at least one of the following: feed water pump RB, furnace water pump RB, coal mill RB, air preheater RB, primary fan RB, and draft fan RB. the

For example, when conducting a fan RB test, the main parameters of the above-mentioned unit include: unit load, main steam pressure, coal quantity, and gas turbine valve; RB project parameters include: sliding pressure target and sliding pressure rate. The above-mentioned establishment of the dynamic characteristics between the main parameters of the unit corresponding to the RB project based on the main parameter disturbance test specifically includes: obtaining the dynamic characteristics of the main steam pressure and unit load under different loads of the boiler according to the coal quantity disturbance test; obtaining the dynamic characteristics of the boiler under different loads according to the valve disturbance test Lower main steam pressure and unit load dynamic characteristics. the

For another example, when performing feedwater pump RB, the above-mentioned main parameters of the unit include: water volume, drum water level, and steam volume; the above-mentioned RB project parameters include: the maximum value of the feedwater pump scoop tube and the maximum speed of the feedwater pump scoop tube. The above-mentioned dynamic characteristics between the main parameters of the unit corresponding to the RB project established based on the main parameter disturbance test include: according to the steam volume disturbance test, the dynamic characteristics of the steam drum water level under the steam volume disturbance are obtained; according to the spoon tube disturbance test, the steam drum water level under the spoon tube disturbance is obtained dynamic characteristics. the

Hereinafter, the embodiment of the present invention will be described in detail by taking a fan RB test as an example. the

1. In order to establish the RB system simulation model, it is necessary to distinguish the identification links according to the system structure, whether the signals are measurable, and the correlation between the signals, and determine the transfer function of each link by deriving the dynamic process of the control system. the

When it is necessary to establish the dynamic characteristics among the parameters of unit load, main steam pressure, coal quantity, and steam turbine control valve, the working condition of the unit should be stable first, and the interference of other factors should be minimized. The specific dynamic characteristic test process is as follows:

a) Coal disturbance test

In the two stages of unit load 50% MCR and 70% MCR, and under the condition of stable unit load, release the main control of the boiler automatically, keep the valve position of the main unit unchanged, and manually increase the fuel volume by 10t/h or more in steps. Test the change trend of the main steam pressure and load of the unit, obtain the transfer function of the main steam pressure and load to the coal quantity under different loads of the boiler, and record the generation time of the main steam pressure and load of the boiler (that is, pure delay). That is, the fueling test is carried out first, and after the test ends and the load stabilizes, the fuel quantity is manually reduced by 10t/h, and the boiler characteristics are tested and modeled when the load is raised and lowered respectively. the

b) Valve disturbance test

In the two stages of unit load 50% MCR and 70% MCR, under the condition of stable unit load, release the main control of the boiler automatically, keep the coal volume unchanged, and manually increase the valve opening (combined valve position) of the main unit by 5% quickly and step by step Or above, test the change trend of the main steam pressure and load of the unit, obtain the transfer function of the main steam pressure and load to the valve under different loads of the boiler, and record the generation time of the main steam pressure and load of the boiler (that is, pure delay). That is, the valve opening characteristic test is carried out first, and after the test is completed and the load is stable, the valve opening (combined valve position) of the large machine is manually reduced by 5%, and the boiler characteristics are tested and modeled when the load is raised and lowered. the

c) Constant pressure variable load test

In the constant pressure operation mode, put into coordination, and carry out the variable load rate test. The test range is in the 50%-100% load range, the variable load value is planned to be 50-100MW, and the variable load rate is gradually changed from 5MW/min to 9MW/min, 12MW/min, and the main parameter change trend of the unit is observed and modeled. the

d) Constant load variable voltage test

The operating personnel manually change the target value of the pre-machine pressure in the constant pressure mode, and the change rate of the pre-machine pressure is about 0.2MPa/min. According to the response curve, the change trend of the main parameters of the unit is observed and modeled. the

After the above tests are completed, the input and output parameters of each identification link are derived from the historical trend of the actual DCS system of the unit, and the mathematical model structure diagram of the adjustment system is established by using the transfer function method, and the recursive least squares identification algorithm is used to determine the parameters in the model. The parameters of the model to be identified. It can identify the dynamic characteristics of the pressure under fuel disturbance, the dynamic characteristics of the load under fuel disturbance, the dynamic characteristics of the pressure under the door adjustment disturbance, and the dynamic characteristics of the load under the door adjustment disturbance, and compare the parameters of the identified model with the original data curve to determine the identification accuracy ok. In the same way, the characteristics of all dynamic links related to the test project can be identified for the specific RB test project, and the model library can be built in the simulation software to simulate the actual state when RB occurs. the

2. In order to evaluate the RB capability of the unit, a single mill trip disturbance test should be carried out before the RB test. Obtain the dynamic characteristics of the influence of single mill tripping on the main parameters of the unit through experiments, including: Obtaining the dynamic characteristics of single mill tripping on unit load, main steam temperature, main steam pressure, steam drum water level, primary air pressure, furnace negative pressure, and total air volume characteristic. In this way, the obtained dynamic characteristic information can provide an analysis basis for the changes of each main parameter in the RB experiment. the

3. For the RB projects to be carried out (including feed water pump RB, boiler water pump RB, air preheater RB, primary fan RB, supply and induced draft fan RB), according to the predetermined test sequence, build a simulation model and platform for a single RB test one by one, Under normal circumstances, the test is carried out in accordance with the principle of success rate from high to low, followed by the induced draft fan RB, the air preheater RB, the primary fan RB, the boiler water pump RB, and the feed water pump RB. After building a single RB model, simulate the RB project parameters set in the RB test according to the dynamic characteristics and parameters obtained in the above-mentioned 1 and 2, estimate the results of the actual RB test and perform corresponding optimization. And through the actual RB test, the simulation model is continuously improved and corrected. the

In the embodiment of the present invention, the computer control system (such as DCS system) of the power plant unit and the modeling simulation analysis software (such as Matlab) are jointly implemented. Various control signals can be obtained by sampling through DCS, and the configuration of the logic scheme is also realized in DCS. The PID, addition block, filter block, subtraction block, multiplication block, non-disturbance switching module, MA hand-operated device, etc. used in the embodiments are all commonly used algorithm blocks in digital control systems, and their setting and calculation are relatively convenient. The Simulink module group in Matlab is a dedicated software package for modeling, simulating and analyzing dynamic systems. It supports linear and nonlinear systems and can be modeled in continuous and discrete time domains. It is widely used in signal processing and automatic areas of control. Through Simulink modeling and simulation, first optimizing the control scheme of RB under each working condition is the basis of its control. On the premise of effective control scheme selection, further targeted adjustment of each control parameter can achieve the best effect. the

In actual operation, primary fan RB is the RB project with the highest failure rate among fan RBs, while the primary success rate of draft fan RB and air preheater RB is relatively high, and the optimization methods, steps, and modeling and simulation processes of the latter are all Consistent with the former, only the modeling objects are different. the

The specific implementation of the embodiment of the present invention will be described in detail below by taking the primary fan RB and the water feed pump RB as examples. the

1. A 300MW drum boiler uses two primary fans. When the primary fan is RB, the sliding pressure target should follow the slow release of boiler heat, not the economical sliding pressure curve. Because the sliding pressure setting value and sliding pressure rate in the existing RB scheme are set according to certain empirical values, the setting is unreasonable, which leads to the failure of the primary fan RB test. Taking the setting value of sliding pressure and setting of sliding pressure rate as examples, the process of setting and optimizing the RB parameters of this scheme is explained: 

1) Through the specific disturbance test plan in the above step 1 to establish the dynamic characteristics among the parameters of unit load, main steam pressure, coal quantity, and steam turbine control valve. the

The first is the coal quantity disturbance test, which tests the characteristics of the boiler steam generation time and the load and pressure under the coal quantity disturbance. That is, under the condition that the load of the unit is 210MW and the load of the unit is stable, the main control of the boiler and the automatic control of the main control of the unit are released, and the fuel volume is increased by 10t/h in a rapid step manually, and the change trend of the main steam pressure and load of the unit is tested, and the transfer of the boiler object is obtained. function. The test data and graphics are recorded and saved by the historical data trend analysis function of the DCS system of the power plant, and can be directly exported from the DCS system for model fitting. The data sampling period is 1s, the collection time is 1600s, and 1600 sets of data are obtained. Due to the fact that there are high-frequency parts that are not conducive to identification in the actual measured data on site, in order to improve the identification accuracy, the bad points in the data set are eliminated, and the data set is filtered with an average value of 1.5s, and then the trend and The load and pressure dynamic characteristic curves of the coal quantity disturbance test directly derived from the DCS system are shown in Figure 2. the

For the direct-blown pulverizing system, the pure delay time delay τ of the response characteristics of the main steam pressure to the combustion rate in the process from the change of the combustion rate to the beginning of the change of the main steam pressure is t1 in Fig. 2. About 67.3% of the time from the beginning of the pressure change to the final pressure stabilization (ie t2 in Fig. 2) is the inertia time delay Tc. The pure delay time delay τ of the main steam pressure soaring characteristics measured by the test is 50s, and the inertia time delay Tc is 406s, and the transfer function of the coal mass to the main steam pressure is obtained as: $G_{11}\left(S\right)=\frac{0.17}{40000{\mathrm{the\; <figure-callout\; id="2"\; label="s"\; filenames="HDA0000117079260000042.png,HDA0000117079260000052.png"\; state="\{\{state\}\}">s</figure-callout>}}^2+406\mathrm{the\; s}+1}{e}^{-50\mathrm{the\; s}}.$

According to the specific disturbance test program in the above step 1, the overall dynamic characteristics are as follows:

Pressure versus load characteristic function: $G_{12}\left(\mathrm{the\; s}\right)=\frac{0.459}{400{\mathrm{the\; <figure-callout\; id="2"\; label="s"\; filenames="HDA0000117079260000042.png,HDA0000117079260000052.png"\; state="\{\{state\}\}">s</figure-callout>}}^2+40\mathrm{the\; s}+1};$

The characteristic function of the tone to the pressure is obtained when the coordination is invested in the early stage; $G_{\mathrm{twenty\; one}}\left(\mathrm{the\; s}\right)=\frac{-0.2}{6400{\mathrm{the\; <figure-callout\; id="2"\; label="s"\; filenames="HDA0000117079260000042.png,HDA0000117079260000052.png"\; state="\{\{state\}\}">s</figure-callout>}}^2+160\mathrm{the\; s}+1};$

Characteristic function of pitch versus load $G_{\mathrm{twenty\; two}}\left(\mathrm{the\; s}\right)=\frac{4.36}{6{\mathrm{the\; <figure-callout\; id="2"\; label="s"\; filenames="HDA0000117079260000042.png,HDA0000117079260000052.png"\; state="\{\{state\}\}">s</figure-callout>}}^2+4\mathrm{the\; s}+1}.$

Applying the above characteristic function to the Matlab simulation model, the pressure load characteristic trend diagram of coal quantity disturbance is obtained as shown in Figure 3. the

2) Before the RB test, the single mill tripping disturbance test was carried out. the

Before the test, the main parameters of the operation of the unit load at 300MW are the four-layer mill operation of A mill, B mill, C mill and D mill, the total coal amount is 123t/h, the furnace negative pressure is -111Pa, the unit load is 300MW, and the main steam temperature is 491℃ . The operating personnel stopped the D mill manually, the large machine adjustment door and coal volume control were in manual mode, the coal volume jumped to 90t/h, the unit load dropped from 300MW to 252MW at an average speed of 6.3MW/MIN, and the main steam pressure dropped from 16.02MPa , Reduce to 14.06MPa at an average speed of 0.38MPa/MIN, the lowest furnace negative pressure drops to -502Pa, the lowest main steam temperature is 477°C, and tends to be stable after 9 minutes. According to the coal mill tripping disturbance test and dynamic characteristics results, the RB simulation environment shown in Figure 4 is constructed. the

Substitute the characteristic functions of G ₁₁ (s), G ₁₂ (s), G ₂₁ (s), and G ₂₂ (s) obtained in 1) above into the model shown in FIG. 4 . It is known that when the site is at 300MW, the total coal volume is 123t/h, and the coal volumes of the D and C floor mills where the primary fan RB will trip are 30t/h and 33t/h respectively at full load. In the RB control logic, the target coal volume is to keep 70t/h for operation, so setp1 in Figure 4 (that is, the coal volume setter to be reduced for mill D tripping) is -30t/h, and setp2 in Figure 4 (that is, mill C for 10s The coal quantity setting device to be reduced after tripping) is set at -33t/h after 10s, since the target coal quantity is reserved at 70t/h, step3 in Figure 4 (that is, the coal quantity setting device of the main combustion control) is set at After 15s, add 17t/h of coal, and simulate the change of total coal when RB occurs through the superposition of the three. At the same time, the dynamic setting value of the main steam pressure in the RB test is constructed by step6 (that is, the sliding pressure target value setter) to construct the sliding pressure target value and the sliding pressure rate setter, to simulate the actual load and pressure changes when RB occurs The process is constructed by four dynamic characteristics of G ₁₁ (s), G ₁₂ (s), G ₂₁ (s), and G ₂₂ (s). The actual load change process can be obtained by adjusting the door-to-load characteristics and pressure-to-load characteristics. Through the above-mentioned overall modeling, the actual change process parameters of the pressure can be compared, and the sliding pressure target and rate suitable for the pressure setting value can be reversed under the premise of ensuring a stable load. Figure 5 is a trend diagram of the dynamic changes of the RB test simulation model simulating the actual test.

3) Analyze simulation results and optimize parameter settings

Through the above simulation 300MW primary wind RB test, when the current pressure drops by 0.39MPa when RB occurs, RB has reached the load of 160MW, and the load has dropped by 148MW within 4 minutes. The simulation test results show that the ideal sliding pressure target value is 14.8MPa, the sliding pressure rate is 0.15MPa when the RB operates, and the RB signal should be reset when the RB operates to 160MW. At this time, the sliding pressure can be converted to a constant pressure mode. Resume operation. The test results show that the curve shown in Figure 5 is more accurate in simulating the actual RB process of the sliding pressure mode. Referring to the simulation results, reset the sliding pressure setting value and sliding pressure rate and re-do the RB test of the fan again. The result of the RB test of the fan is a one-time success. Figure 6 is the trend diagram of the new primary wind RB action, and Table 1 is the main parameter values of the actual primary wind RB test. the

Table 1

the minimum Highest set value unit load 146 203 the MW main steam pressure 15.25 15.7 Sliding pressure, sliding pressure rate 0.15MPa MPa Furnace pressure -1104 880 -50 Pa Primary wind pressure 6 8.05 Sliding pressure 10.35-9 kPa Drum water level -119 1.7 0 mm main steam temperature 452 473 Slide 537-535 ℃ Air volume 630 799 Slide 800-640 t/h

2. The water supply system of a 600MW steam drum boiler uses three electric pumps. The RB test of the feed water pump was performed under the tripping accident of a single feed water pump. Due to the unreasonable setting of the maximum value and the maximum speed of the feed water pump scoop tube in the existing RB scheme, resulting in Sheung Shui Affected, at the same time, the unbalanced soda water makes the water level of the steam drum too low to trigger a low 3 value, and the MFT action test fails. The following takes the optimization of the setting of the actuator of the feedwater pump as an example to illustrate the setting process of the RB parameters of this scheme:

1) Obtain the dynamic characteristics between the parameters of water supply, steam drum water level and steam volume, such as the dynamic characteristics of steam drum water level under steam flow disturbance $W_{31}=\frac{1}{25\mathrm{the\; s}+1}+\frac{-0.0121}{\mathrm{the\; s}};$ Dynamic characteristics of steam drum water level under electric pump spoon tube disturbance $W_{32}=\frac{2.1}{10\mathrm{the\; s}+1}{e}^{-6\mathrm{the\; s}}\&Center\; Dot;\frac{0.0131}{100{\mathrm{the\; <figure-callout\; id="2"\; label="s"\; filenames="HDA0000117079260000042.png,HDA0000117079260000052.png"\; state="\{\{state\}\}">s</figure-callout>}}^2+\mathrm{the\; s}}.$

The simulation structure and dynamic process of the completed overall dynamic model, Fig. 7 is the simulation diagram of the control scheme of steam and water dynamic characteristics when RB occurs, as shown in Fig. 7, the deviation between the set value and the actual water level of the drum Through the action of the two PID blocks of the main tuner and the auxiliary tuner, the opening value of the scoop tube of the feed water pump is finally calculated, and the dynamic influence of the scoop tube opening on the water level can be simulated by the pump scoop tube to the feedwater flow characteristics and the feedwater flow to the water level characteristics; At the same time, when the RB trigger signal is triggered in Figure 7, the corresponding main steam flow calculated by the load reduction after the RB trigger can simulate the dynamic change of the steam reduction to the water level after the RB is triggered, and the model in Figure 7 Dynamically simulate the unbalance of main steam flow and feed water flow after RB is triggered, and the final influence value of the unbalance of steam and water on the steam drum water level under the maximum limit value allowed by the scoop tube. the

Fig. 8(a) is the change trend diagram of the water level when the load is constant and only the set value of the water level is disturbed in the test; Flow and drum water level transient change trend diagram. the

2) Analyze simulation results and optimize parameter settings

Analyzing the simulation test results, it can be calculated that for a 600MW subcritical steam drum boiler, if the influence of the cycle rate is ignored, according to the calculation of the effective volume between the upper and lower water levels of the steam drum, the "water shortage and dry pot" can occur in 8.4s under the rated evaporation. "Accidents, so the imbalance of soda water has a greater impact on the water level. The simulation results show that the dynamic process of 20% change of the spoon tube can make up 101t/H more water supply, which is the key to the rapid and stable water level. The fast adjustment rate of the spoon tube is another key factor. When the maximum adjustment rate of the spoon tube reaches 2.0%/s, the water level can quickly return to the set value and stabilize. According to the simulation results, the high limit of the spoon tube is set at 76%, and the adjustment rate of the spoon tube is 1.8%/s, and the maximum output test of a single electric pump is carried out in cooperation with the boiler professional to ensure that the speed and current of the electric pump under the above values will not be too large. Trigger electrical protection action. the

According to the parameters set according to the simulation results, the RB test of the feed water pump was re-conducted, and the RB test of the new feed water pump was successful once. The working conditions of the unit before the test are as follows:

Unit load: 579MW

Coordinated control mode: Furnace and machine coordination

Running mill conditions: A, B, C, E, F

Total coal supply: 226t/h

Front pressure: 16.88MPa

Drum water level: 35.91mm

Furnace negative pressure: -160Pa

Main steam temperature: 540℃

Reheat steam temperature: 534°C

Spoon Tube Tracking Bits: 55%

00:37 The operating personnel stopped the B pump on the spot. After the B pump stopped, the unit coordination control mode was automatically switched from the furnace to the machine coordination to the machine following mode. The unit load was reduced from 579MW at a speed of 900MW/MIN to 300MW, and after 5 minutes it tended to more stable. the

Figure 10 is a real-time trend analysis diagram of the dynamic change of steam and water in the actual water supply pump RB test after adopting the newly set parameters, and Table 2 is the main parameter value of the newly set actual water supply RB test. As shown in Figure 10, the dynamic matching process of steam and feedwater is the slanted part in the figure. The area of the slashed part is the tonnage of the output steam flow greater than the input feedwater flow, which is the gap of steam-water imbalance. The maximum adjustment rate of the actual spoon tube reaches 2.8%/s, and the average adjustment rate is also greater than 1.5%/s, and the current and speed of the pump during this process do not exceed the protection allowable value, which is within a safe range. the

Table 2

the minimum Highest set value unit Drum water level -173 35.91 -- mm Furnace pressure -1890 1980 -120 Pa primary wind pressure 8.04 10.78 10.45-8.95 kPa Front pressure 16.24 17.16 16.20 MPa main steam temperature 490 540 -- ℃ reheat steam temperature 492 529 -- ℃

[0104] Fig. 11 is the action trend diagram of the feedwater pump RB simulation test after adopting the newly set parameters. According to Fig. 10 and 11, the results of the actual RB test and the simulation test results are more similar.

Example two

The embodiment of the present invention also provides a device for determining RB project parameters in a power system, as shown in Figure 12, the device includes:

The main parameter dynamic characteristics establishment unit 1 is used to establish the dynamic characteristics between the main parameters of the unit corresponding to the RB project according to the main parameter disturbance test;

The system simulation model establishment unit 2 is used to establish the system simulation model corresponding to the RB project according to the actual working system;

The simulation test execution unit 3 is used to carry out the RB project simulation test in the system simulation model according to the dynamic characteristics between the main parameters of the unit;

The RB item parameter determination unit 4 is configured to determine the RB item parameters according to the RB item simulation test results. the

It can be seen from the above description that the dynamic characteristics between the RB project and the main parameters are firstly established by the main parameter dynamic characteristic establishment unit, and then the system simulation model establishment unit establishes the simulation system, and the RB simulation test is carried out by the simulation test execution unit, and then the RB project The parameter determination unit determines the RB project parameters according to the simulation test results, and the RB project parameters determined by modeling are better than the empirical values in the prior art, and the success rate and stability of the actual RB test are better improved. the

As shown in Figure 13, the above-mentioned device also includes:

The single mill tripping-main parameter dynamic characteristic acquisition unit 5 acquires the dynamic characteristics between the single mill tripping and the main parameters of the unit according to the single mill tripping disturbance test. the

Specifically, the RB project simulation test performed by the above simulation test execution unit includes at least one of the following: RB simulation test of feed water pump, RB simulation test of boiler water pump, RB simulation test of coal mill, RB simulation test of air preheater, RB simulation test of primary fan Test, draft fan RB simulation test. the

When the above-mentioned simulation test execution unit performs a fan RB simulation test, the main parameters of the above-mentioned unit include: unit load, main steam pressure, coal quantity, and gas turbine control valve; the above-mentioned RB project parameters include: sliding pressure target and sliding pressure rate. As shown in Figure 14, the main parameter dynamic characteristic establishment unit 1 includes:

The first main parameter dynamic characteristic building module 11 is used to obtain the main steam pressure and unit load dynamic characteristics of the boiler under different loads according to the coal quantity disturbance test;

The second main parameter dynamic characteristic establishment module 12 is used to obtain the main steam pressure and unit load dynamic characteristics under different loads of the boiler according to the valve disturbance test. the

When the above-mentioned simulation test execution unit executes the RB simulation test of the feedwater pump, the main parameters of the above-mentioned unit include: water volume, steam drum water level, and steam volume; the above-mentioned RB project parameters include: the maximum value of the feedwater pump scoop tube and the maximum speed of the feedwater pump scoop tube. As shown in Figure 15, the main parameter dynamic characteristic establishment unit 1 can also include:

The third main parameter dynamic characteristics building module 13 is used to obtain the dynamic characteristics of the drum water level under the steam quantity disturbance according to the steam quantity disturbance test;

The fourth main parameter dynamic characteristic establishing module 14 is used to obtain the dynamic characteristic of the steam drum water level under the spoon-tube disturbance according to the spoon-tube disturbance test. the

For the specific execution process of the above units and modules, reference may be made to the description in the above Embodiment 1, which will not be repeated here. Moreover, the specific setting of each unit and each module may be a unified setting or a single setting, and the present invention is not limited thereto. the

It can be seen from the above description that in order to improve the one-time success rate of the RB test of thermal power generating units, the embodiment of the present invention proposes a new optimization method for RB testing, based on the transient and steady-state objects of thermal power generating units under different working conditions Characteristics, starting from dynamic modeling, several key analog quantities that directly affect the success of RB (coal volume change rate, main steam pressure change rate, sliding pressure target value, coal reduction target value, limit value and limit rate of important auxiliary equipment etc.) to optimize the settings. The optimization scheme of the new RB experiment simulates the actual parameter change process when the real RB occurs, estimates the subsequent impact, and sets the parameters accurately, so as to realize the optimal selection of the control scheme and parameters. By building the RB dynamic model and making full use of the advantages of simulation technology, the problem of coupling interference of various parameters in the process of RB parameter setting and the difficulty of previous parameter setting relying entirely on personnel experience have been solved, and the limitations of conventional setting methods have been overcome; at the same time, this The algorithm enables the determined RB parameter optimization scheme to be pre-evaluated and continuously optimized, so as to achieve the optimal effect of minimizing the expected risk. the

For thermal power generation units, the optimization of RB control strategy based on dynamic modeling can improve the analysis and setting efficiency and shorten the system adjustment period (actually 30 -The dynamic process of 50 minutes can be realized in only 3-5 seconds in matlab), and avoid the huge impact of the unsuccessful RB test on the safe and stable operation of the unit under the conventional method; improve the control accuracy of the system, and complete the completion that cannot be completed manually The complex calculation and control evaluation index; its fast calculation and convenient modification of parameters can fully compare different design schemes and different parameter combinations, so as to realize the best selection of control schemes and parameters. Generally speaking, the embodiment of the present invention can quickly get rid of the cumbersome parameter setting from the focus of on-site technology, and put more energy on the optimization of the RB scheme. At the same time, it is also positive for the application of modern control schemes such as intelligent control in power plant automation as soon as possible. significance. the

Those of ordinary skill in the art can understand that all or part of the steps in the methods of the above-mentioned embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, such as ROM/RAM, disk , CD, etc. the

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Protection scope, within the spirit and principles of the present invention, any modification, equivalent replacement, improvement, etc., shall be included in the protection scope of the present invention. the

Claims (14)

1. a method for determining RB project parameters in an electric power system, is characterized in that, described method comprises: Establish the dynamic characteristics between the main parameters of the unit corresponding to the RB project according to the main parameter disturbance test; Establishing a system simulation model corresponding to the RB project according to the actual working system; Carry out the RB project simulation test in the system simulation model according to the dynamic characteristics between the main parameters of the unit; The RB item parameters are determined according to the RB item simulation test results. 2. The method according to claim 1, characterized in that, before establishing the dynamic characteristics between the main parameters of the unit corresponding to the RB project according to the main parameter disturbance test, the described method also includes: According to the single mill trip disturbance test, the dynamic characteristics between the single mill trip and the main parameters of the unit are obtained. 3. The method according to claim 2, wherein the RB item comprises at least one of the following: Feed water pump RB, furnace water pump RB, coal mill RB, air preheater RB, primary fan RB, and induced draft fan RB. 4. The method according to claim 3, wherein when the RB item is a primary fan RB, The main parameters of the unit include: unit load, main steam pressure, coal quantity, gas engine regulating valve; The RB item parameters include: sliding pressure target and sliding pressure rate. 5. method according to claim 4, is characterized in that, described according to main parameter perturbation test, establishes the dynamic characteristics between the main parameters of the corresponding unit of RB project comprising: According to the coal quantity disturbance test, the dynamic characteristics of the main steam pressure and unit load under different loads of the boiler are obtained; According to the valve disturbance test, the dynamic characteristics of main steam pressure and unit load under different boiler loads are obtained. 6. The method according to claim 3, characterized in that, when the RB item is a feedwater pump RB, The main parameters of the unit include: water volume, drum water level, and steam volume; The RB project parameters include: the maximum value of the scoop tube of the feed water pump and the maximum speed of the scoop tube of the feed water pump. 7. The method according to claim 6, wherein the dynamic characteristics between the main parameters of the unit corresponding to the RB project according to the main parameter disturbance test are established: According to the steam volume disturbance test, the dynamic characteristics of the steam drum water level under the steam volume disturbance are obtained; According to the spoon-tube disturbance test, the dynamic characteristics of the water level of the steam drum under the spoon-tube disturbance are obtained. 8. A device for determining RB project parameters in an electric power system, characterized in that the device comprises: The main parameter dynamic characteristics establishment unit is used to establish the dynamic characteristics between the main parameters of the unit corresponding to the RB project according to the main parameter disturbance test; A system simulation model establishment unit, configured to establish a system simulation model corresponding to the RB project according to an actual working system; The simulation test execution unit is used to perform the RB project simulation test in the system simulation model according to the dynamic characteristics between the main parameters of the unit; The RB item parameter determination unit is configured to determine the RB item parameters according to the RB item simulation test results. 9. The device according to claim 8, further comprising: The single mill tripping-main parameter dynamic characteristic acquisition unit acquires the dynamic characteristics between the single mill tripping and the main parameters of the unit according to the single mill tripping disturbance test. 10. The device according to claim 9, wherein the RB project simulation test performed by the simulation test execution unit comprises at least one of the following: Feed water pump RB simulation test, furnace water pump RB simulation test, coal mill RB simulation test, air preheater RB simulation test, primary fan RB simulation test, draft fan RB simulation test. 11. The device according to claim 10, characterized in that, when the simulation test execution unit performs a fan RB simulation test, The main parameters of the unit include: unit load, main steam pressure, coal quantity, gas engine regulating valve; The RB item parameters include: sliding pressure target and sliding pressure rate. 12. The device according to claim 11, wherein the main parameter dynamic characteristic establishing unit comprises: The first main parameter dynamic characteristic building module is used to obtain the main steam pressure and unit load dynamic characteristics under different loads of the boiler according to the coal quantity disturbance test; The second main parameter dynamic characteristic building module is used to obtain the main steam pressure and unit load dynamic characteristics of the boiler under different loads according to the valve disturbance test. 13. The device according to claim 10, characterized in that, when the simulation test execution unit executes the feedwater pump RB simulation test, The main parameters of the unit include: water volume, drum water level, and steam volume; The RB project parameters include: the maximum value of the scoop tube of the feed water pump and the maximum speed of the scoop tube of the feed water pump. 14. The device according to claim 13, wherein the main parameter dynamic characteristic establishing unit comprises: The third main parameter dynamic characteristic building module is used to obtain the dynamic characteristics of the steam drum water level under the steam quantity disturbance according to the steam quantity disturbance test; The fourth main parameter dynamic characteristic building module is used to obtain the dynamic characteristics of the water level of the steam drum under the spoon-tube disturbance according to the spoon-tube disturbance test.

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