KR20100048487A - Control method for fast and stable load control by compensating turbine and boiler response delays in power plants - Google Patents

Abstract

PURPOSE: A control method for a fast and stable load control by compensating turbine and boiler response delays in power plants are provided to prevent rapid life-shortening of a main and emergency equipment of power generation system by preventing the delay of generation output variation and maintaining a boiler and a turbine stable. CONSTITUTION: In a control method for a fast and stable load control by compensating turbine and boiler response delays in power plants, a unit master controls change the output of a power generation system (s10). A boiler master is controlled to supply a fuel, water, combustion air to a boiler auxiliary equipment based on the unit master signal(S12). The turbine master controls a steam valve of a turbine and control the output of power output(S14). An input is controlled by dynamical response compensation of the boiler master when output request value change.

Description

CONTROL METHOD FOR FAST AND STABLE LOAD CONTROL BY COMPENSATING TURBINE AND BOILER RESPONSE DELAYS IN POWER PLANTS}

The present invention relates to a control method for improving the stability of power plant output control by the response delay compensation of boiler and turbine, and more particularly, in the field of design and manufacture of a control system for controlling a boiler and a turbine and its auxiliary equipment. The present invention relates to a control method for improving the stability of power plant output control by boiler and turbine response delay compensation that can contribute to stability.

The unit master at the top of power plant control and the lower part of the unit control the boiler master and the turbine master, which controls the entire boiler and turbine.In the past, simple control was performed by analog circuit, but in modern times, digital control using computer technology The system combines standardized function blocks and adjusts internal parameters to achieve the desired control algorithms.

In power plants where a turbine generator that responds within seconds to a large boiler with a time delay of more than a few minutes in the process will typically have poor boiler stability and attempt to increase the power output from the turbine generator. Overshoot: There is a case where the plant is stopped due to unstable operation due to large overshoot. The maintenance of the plant increases due to frequent leakage of boiler tube. In response to this problem, each power plant is operating with stability by limiting the maximum output fluctuation rate, but in this case, the system load followability is lowered and the system frequency stability is lowered.

In the power plant, a process that is difficult to control, complex control methods are designed and implemented by Control Logic, which traditionally relies on proportional, derivative, and integral control (PID control) methods. Delays in fluctuations occur, for example, when changing the 25% generation output at a rate of 5% per minute, the design time is 5 minutes, but in practice it is typically 8 to 9 minutes. In general, when the power output fluctuation starts, the unit master sends an output indicator signal to the boiler master and the turbine master at the same time, which causes instability in the coal-fired power plant due to the large delay in the operation time.

Moreover, the power plant must be able to follow its power generation output quickly according to the load of the power system. For many reasons, the speed of output increase and decrease is limited and the operation condition of the boiler turbine becomes unstable. In such a transitional period, the overall stability of the plant's transient stability must be maintained within the specified range, and in the event of severe instability, the plant will be shut down to protect the plant. Therefore, the increase / decrease rate (change speed) of the power plant is often limited, which hinders the operation of the power supply, and when the power generation rate is lowered, the power plant profit is reduced.

The present invention has been made to solve the above problems, the object of the present invention is to prevent the delay of power generation output fluctuations in a power plant using coal, solid fuel, etc. with a large time delay during processing, transportation and combustion of boiler fuel and And boilers to provide better quality power by keeping turbines in a more stable state, preventing plant emergency shutdowns and rapid shortening of plant mains facilities, and ultimately improving the ability to follow power generation output for power system power demand. And a control method for improving power plant output control stability by turbine response delay compensation.

In addition, another object of the present invention is to effectively overcome the response time delay caused by the transfer, processing (pulverized coal) and combustion of the fuel in the boiler to perform a stable control so that the boiler is not unstable, such as fuel, air and water supply It prevents overshoot of boiler input, prevents delay of reaching the target load by changing the actual output linearly as the set value when power generation output changes, and effectively prevents the difference of response time delay between boiler and turbine. Compensation cooperative control can be implemented, and a more aggressive model-base modern control technology provides a control method for improving the stability of power plant output control by boiler and turbine response delay compensation that enables faster output response.

In order to achieve the above object, the present invention includes the steps of: A) controlling the unit master to operate by changing the generator output in accordance with the target output setting and the required output change rate of the power plant; B) controlling the boiler master to supply fuel, water supply and combustion air to the lower boiler auxiliary facilities based on the signal of the unit master; C) controlling the turbine master to control the generator output by adjusting the steam valve of the turbine based on the signal of the unit master; And D) controlling the input according to the dynamic response compensation of the boiler master when the output demand varies by the control of the unit master, the boiler master, and the turbine master.

In addition, step B) and step C) in the present invention is characterized in that it is performed at the same time.

In addition, the step B) and the step C) in the present invention is characterized in that it is linked to cooperate with each other to control the steam pressure and temperature of the power plant.

In addition, the step A) in the present invention, a) output command by the remote power signal in the power supply command; b) setting a target output through a signal generator during operation of the unit master; c) the upper or lower limit output limit signal of the target output and the signal passing through the selector do not exceed the limit value as an output command; d) tracking the actual output by selecting the actual power output in the selector and disregarding the lower limit output limit signal if it is not cooperative control of the boiler and turbine in the operation mode of the unit master; e) controlling the rate of change of the signal and limiting the rate of change in output deceleration or output rise or output deceleration to a predetermined target; f) the frequency signal for the frequency following operation is inputted as a frequency error to be added to or subtracted from the unit master signal, so that the output is added or decremented, and a continuous increase or decrease signal is added to the unit master signal at the time of output rise or output deceleration; And g) the generator output is suddenly decelerated when a part of the boiler auxiliary equipment is stopped and a target transmission signal is transmitted and supplied as a command signal of the turbine master and the boiler master; Characterized in that it comprises a.

In addition, the step B) in the present invention includes the steps of: a) the output request signal of the unit master is scaled to fit the boiler auxiliary equipment to become a reference signal of the boiler master; And b) selecting the cooperative control mode or the boiler following control mode of the boiler and the turbine and outputting a corresponding result.

In addition, in the present invention, when selecting the cooperative control mode of the boiler and the turbine in the step b), after the steam pressure error is detected in the subtraction block is supplied to the proportional integral derivative controller to control the steam pressure.

In the present invention, when the boiler following control mode is selected in the step b), the boiler master is characterized in that the input of the entire boiler by the main steam pressure error.

In addition, the step C) in the present invention, a) the output request signal supplied from the unit master is a reference signal of the turbine master; b) compensating for a time delay of a boiler larger than a turbine in calculating the reference signal; And c) selecting a cooperative control mode or a turbine following control mode of the boiler and the turbine according to the time delay compensation.

In addition, in the present invention, when selecting the cooperative control mode of the boiler and the turbine in the step c), after the steam pressure error is detected in the subtraction block is supplied to the proportional integral derivative controller to control the output.

In addition, in the present invention, when the turbine following control mode is selected in the step c), the turbine master is characterized in that the operation of the turbine valve by the main steam pressure error.

In addition, in the present invention, the frequency error of the turbine and the generator speed deviation is scaled for the frequency control operation during the step C), and the turbine master signal in the cooperative control mode or the turbine following control mode of the boiler and the turbine is added or subtracted. It features.

In addition, the step D) in the present invention includes the steps of: a) output request value power station output request signal is changed to generate a signal in a direction to help the output change in the differentiator to add a signal to the boiler master; And b) programming the differential signal in a function generator to adjust its magnitude according to the output period.

Further, in the step D) of the present invention, filtering is required as the first delay of the differential signal, but the delay constant is programmed according to the output interval band in the function generator, and the differential signal is decreased when the output increase / deceleration is completed. And the ratio is programmed according to the output section of the function generator.

In addition, the present invention is characterized in that a signal change appears exponentially instead of a change rate limiter that increases or decreases at a constant rate during the dynamic response to generate a compensation signal.

In order to achieve the above object, the present invention includes the steps of: A) controlling the unit master to operate by changing the generator output in accordance with the target output setting and the required output change rate of the power plant; B) controlling the boiler and turbine master using an advanced controller to implement an output control enhancement technique based on the signal of the unit master; And C) controlling the input according to the dynamic response compensation of the boiler master when the output demand varies by the control of the unit master, the boiler master, and the turbine master.

In addition, the step B) in the present invention, a) in response to the variation of the output request signal supplied from the unit master in order to predict the control of the boiler with a slow response to the stable signal and the leading signal in the model base transfer function generator Generating; b) adding the stable leading signal and the dynamic leading signal, which is a steep leading signal, by adding a ratio in a fuzzy logic according to a difference between a final output target value and a current set value to be a leading signal of a boiler master; c) predicting the steam pressure change in accordance with the turbine master and boiler master signals in the model-based transfer function generator; d) applying a setpoint to a proportional integral derivative controller in accordance with said vapor pressure prediction; And e) generating a boiler master signal for controlling fuel, air, and water of the entire boiler by comparing the predicted set value with the actual steam pressure.

As described above, the control method for improving the stability of power plant output control by compensating the delay of the response of the boiler and the turbine is to delay the fluctuation of the power generation output in a power plant using coal, solid fuel, etc., which have a large time delay during processing, transportation and combustion of boiler fuel. To keep the boilers and turbines in a more stable state, preventing plant emergency shutdowns and rapid shortening of the plant's main equipment, and ultimately improving the ability to follow power generation output for power system power demand. It can be effective.

In addition, the power plant output control stability improvement control method by the boiler and turbine response delay compensation of the present invention effectively overcomes the response time delay that occurs in the transfer, processing (pulverized coal) and combustion of the fuel in the boiler so that the boiler becomes unstable. Stable control, prevent overshoot of boiler inputs such as fuel, air and water supply, and when power output fluctuates, the actual output changes linearly as set point to delay the time to reach the target load. It is possible to implement cooperative control to prevent and effectively compensate for the difference in response time delay between the boiler and the turbine, and to implement a faster output response by using a more aggressive model-based modern control technology.

Hereinafter, an embodiment of the power plant output control stability improvement control method by the response delay compensation of the boiler and the turbine of the present invention will be described with reference to the accompanying drawings.

Power plant output control stability improvement control method by the boiler and turbine response delay compensation according to an embodiment of the present invention is a unit master control step (S10), boiler master control step (S12), turbine master as shown in FIG. And a control step S14 and a boiler and turbine response delay compensation step S16.

The turbine master is a device that controls the generator output by adjusting the steam valve of the turbine. The boiler master and turbine master are designed to cooperate with each other to stabilize the plant steam pressure and temperature. Power plant control is configured to transfer signals hierarchically from unit masters to turbine masters and boiler masters, and to boiler controllers.

As shown in FIG. 2, the unit master control step (S10) is a generator top controller so that an operator sets a target output of a power plant and, if necessary, changes the generator output (MW) to operate according to a desired output change rate. To control.

That is, when the step (S10) is described in more detail, it is a part for setting the target output of the power plant and calculating the respective output set value. In the mode where the power plant is operated by the remote control signal of the feeder station, the signal of the remote target (Remote Target: 21) operates as the output command, and when the operator operates in the local mode, the operator operates the generator target through the signal generator 22. Set the output.

The output command signal does not exceed the limit value by comparing the upper limit and lower limit output limit signals of the upper limit and lower limit values 23 and 24 with the signal passing through the selector 25.

If the unit operation mode is not the boiler-turbine cooperative control, the signal of the power production setpoint 27 is ignored and the unit master signal follows the actual output by selecting the actual output of the actual power demand device 29 in the selector 28. (Tracking)

The output variation rate set by the operator comes from the variation rate 30 and controls the variation rate of the signal in the variation rate limiter 31. In run-back, run-up, and run-down, the rate-of-change limiter 31 operates with instantaneous characteristics.

The frequency signal for the frequency following operation is inputted as a frequency error (KdF: 32) in the turbine control system and added to or subtracted from the unit master signal, thereby output is added or decreased according to the frequency.

When run up or run down is needed, the increment 35 or decrement 36 signal is added to the unit master signal continuously. When one of the power plant critical auxiliary equipment is stopped, the generator output suddenly decelerates (runs back), and the target output signal is transmitted from the runback target 38. The signal of the unit master is supplied as a demand signal of the turbine master and the boiler master.

Here, a unit master refers to a power plant, and the master is a concept of a general controller. Requirement loads of power plants (setpoints of power plants to supply electricity for homes, factories, etc., and the need for more oil to speed up cars, and energy such as fuel, water and air to produce more electricity in power plants) The highest control level to set the highest signal of these) is the unit master's set value is the Auto Dispatch System (ADS, generated from the power exchange that monitors the entire Korean power operation). Or set by the plant operator.

The unit master's setpoints send signals to the boilers that produce high-temperature, high-pressure steam using air, fuel, and water, and to the masters of rotating turbines. The turbine rotates like a watermill when hot and high pressure steam enters. And the turbine is connected to the generator to rotate the generator to produce electricity, which is supplied to each home, factory, building, etc. through the transmission line, substation, distribution station of the transmission tower.

The boiler master control step (S12) is a step of controlling the boiler master to supply the fuel, water supply and combustion air to the lower boiler auxiliary facilities based on the signal of the unit master as shown in FIG.

That is, the step S12 will be described in more detail. The boiler master is a boiler main controller that controls fuel, feed water, and combustion air by controlling the lower boiler auxiliary facilities based on the signal of the unit master.

An output request signal (ULD: Unit Laod Demand: 52) supplied from the unit master is scaled according to the lower control signal to become a reference signal of the boiler master. In the boiler-turbine cooperative control mode, the circuit of the left part is selected in FIG. 3. First, when the steam pressure error TPe is detected in the subtraction block 58 on the right side, the proportional integral derivative controller PID: through the adder 60. The main operation is to control the steam pressure by being supplied to 61). At this time, the preceding signal 65 in which the output request signal ULD is scaled is added to the end to increase the quick response.

If the error (MWe: 54) between the output request signal (ULD: 52) signal and the actual generator output (MW: 51) becomes too large, it is added to the adder 60 beyond the deadband 59, so that the actual generator output 51 A corrective action for instability is also added. In other words, the steam pressure is usually controlled, but if the output error is large, this is also reflected in the control, so that the power plant is quickly stabilized.

This static compensation and mutual cooperation do not provide satisfactory control in the increase or decrease of output. Therefore, Dynamic Response Enhancer (69) is additionally configured.

This is a preliminary control by detecting the rate of change of the output request signal 52 by the differential function, but is configured to program the derivative time constant, the addition gain and the delay filter time constant according to the output section.

3, when the boiler following control mode on the right side is selected, the boiler master adjusts the input of the entire boiler (fuel, air, water) by the main steam pressure error, and at this time, the preceding signal operates through the scaled generator output 64. As a result, it performs quick control when load changes.

The Model Based Advanced Boiler Master Control part is configured as shown in FIG. 12.

When the boiler master is operated in manual mode, the fuel, air and water supply can be adjusted simultaneously by directly adjusting the value of the boiler master through the signal generator. The operation modes available in the boiler master are as follows. That is, there are a boiler-turbine cooperative auto mode, a boiler following auto mode, an advanced control auto mode and a manual mode (see FIG. 12).

The turbine master control step (S14) is a step of controlling the turbine master to control the generator output by adjusting the steam valve of the turbine based on the signal of the unit master as shown in FIG.

That is, when the step (S14) is described in more detail, the turbine master is a device for controlling the generator output by adjusting the steam valve of the turbine. The output request signal (ULD) 82 supplied from the unit master becomes the reference signal of the turbine master.

Since proper calculation of this reference signal is most important for stable operation of a power plant, pure delay compensators 85 and 86 have been implemented to compensate for a much larger time delay of a boiler than a turbine. In coal-fired power plants, very long delays occur in fuel transport and crushing, combustion and evaporation, and heat exchange, which have time constants containing pure delays of tens of seconds.

Therefore, when controlling the entire power plant, it is to harmonize the stability of the boiler and the turbine by delaying the turbine input control rather than the boiler. In this case, adding a pure time delay of tens of seconds is a key technique and supplementally includes some first-order delay. Pure time delay is impossible in analogue, but digital controller with large memory realizes pure time delay.

In the boiler-turbine cooperative control mode, the circuit of the left part is selected in FIG. 4. First, the generator output error MWe is detected in the subtraction block 88 on the left, and the proportional integral derivative controller PID is detected through the adder 90. It is the main operation to control the output by being supplied to 91). Of course, signals through the pure time delay compensators 85 and 86 are supplied to the set values of the output control.

At this time, the preceding signal 92 in which the output request signal ULD is scaled is added to the end to increase the quick response. The steam pressure setpoint that supports the transformer operation mode is generated by the delayed output request signal 86 through the function generator and the first order delay filter, and the setpoint and actual vapor pressure error are computed in the subtractor 98, where the deadband is set. If it exceeds 89, it is added to the output error in the adder 90, which also adds a corrective action for steam pressure instability. In other words, the output is usually controlled, but if the steam pressure error is large, this is also reflected in the control, and the plant is quickly stabilized.

On the other hand, while the boiler master control step (S12) and turbine master control step (S14) can be performed at the same time, is linked to cooperate with each other to control the steam pressure and temperature of the power plant.

When the turbine following control mode on the right side of FIG. 4 is selected, the turbine master quickly adjusts the turbine valve due to the main steam pressure error, and at this time, the preceding signal is operated to perform rapid control during load fluctuation. 86, but this signal is corrected by actual pressure and supplied as a preceding signal.

For the frequency control operation, the turbine-generator speed deviation (KdF) in the turbine control system is scaled according to the speed adjustment rate in the function generator to add and subtract the turbine master signal in cooperative control or turbine follow-up control mode.

The Model Based Advanced Turbine Master Control section can adjust the opening demand signal supplied to the turbine valve by directly adjusting the turbine master's value via the signal generator when the turbine master is operated in manual mode. The operating modes available to the turbine master consist of a boiler-turbine cooperative auto mode, a turbine following auto mode, an advanced control auto mode and a manual mode.

The boiler and turbine response delay compensation step (S16) is a step of controlling the input according to the dynamic response compensation of the boiler master when the output demand is changed by the control of the unit master, the boiler master, and the turbine master, as shown in FIG. 5. .

In other words, the step S16 will be described in more detail. When the process stable state is the worst in the power plant, output fluctuations occur. That is, the most unstable state appears during or immediately after the output increase and decrease.

In oil or gas-fired power plants, there is little delay in the fuel processing and supply process, resulting in higher transient and static stability and easier control than coal power plants.

Coal-fired power plants are difficult to control and prone to transient instability due to the large delays in the crushing, transporting and burning of fuels. In the prior art Proportional Integral Controller (PID), it is difficult to control the transient instability, so the preceding control is used to improve the transient control error, but it is not sufficient.

In the present invention, a dynamic response compensator which operates a control algorithm that generates a dynamic preceding signal when the output demand value changes, that is, does not depend on the proportional integral derivative controller (PID) in the transition period, and uses the proportional integral derivative control mainly in a stable state. Dynamic Response Enhancer (DRE) is uniquely implemented and applied.

When the output demand is changed, it is possible to detect the INC and DEC signals by detecting the presence or absence of the change in the output request signal (ULD) by the differentiator, and the DRE circuit is operated by this signal. This is like supplying additional boiler input (fuel) when power is needed, such as stepping on the accelerator in advance when the car goes up a hill.

Output Request Value When the output request signal changes, a signal in the direction that helps the output change in the differentiator 111 is generated, and the signal is added to the boiler master through various correction circuits to stabilize the boiler. This differential signal is programmed in the function generators 115 and 116 such that its magnitude is adjusted in the multiplier 121 or multiplier 122 according to the output interval. In FIG. 5, the left side operates when the output increases and in FIG. 5, the right side operates when the output decreases.

This differential signal needs to be filtered with a suitable primary delay whose delay time constants can be programmed according to the output intervals in the function generators 117 and 118. When the output increase and decrease is completed, it is necessary to gradually reduce the differential signal. The ratio is programmed in the function generator bands 119 and 120 as well.

The signal of the dynamic response compensator is generated by the dynamic response compensator 125 when the output is increased and by the first time delay of the dynamic response compensator 126 when the output is decreased, and the final signal is summed at the final part of the boiler master.

The dynamic response compensators 125 and 126 compensate for the first time by applying an F (t), that is, a time delay function, in which a signal change is exponential instead of a velocity limiter that increases or decreases at a constant rate. Signals are generated effectively and without causing sudden instability. This unique filtering technique prevents instabilities that occur every time the output ramp is completed in the past and the compensation signal returns to its original position.

The operation control screen is a tree structure in which control signals are transmitted hierarchically as shown in FIG. 8, and is displayed on the screen as it is. The target value can be selected by selecting each value and the main control variables of the entire power plant are listed. It is structure that can monitor effectively by chance.

Selecting the model-based output control enhancement technology mode in which modern control theory is implemented allows the operator to select the control system to stop the proportional integral differential control and to control by advanced control technology. Implemented bumpless control without any instability.

According to the automatic and manual selection of the boiler and turbine master, the selection of boiler-turbine cooperative control, boiler following automatic control, turbine following automatic control, and turbine / boiler manual control mode is automatically made.

As shown in FIG. 9, the output change state of the output control enhancement mode (URO) and the general control mode in the improvement trend of output control performance shows that there is almost no output delay.

In accordance with another embodiment of the present invention, a control method for improving power plant output control stability by boiler and turbine response delay compensation includes a unit master control step (S130), a boiler and turbine master control step using an advanced controller ( S132) and the boiler and turbine response delay compensation step (S134).

Here, since the unit master control step (S130) and the boiler and turbine response delay compensation step (S134) has the same structure and function as that of the previous embodiment, a detailed description thereof will be omitted.

The boiler and master control step using the advanced controller (S132) is a step of controlling the boiler and turbine master using an advanced controller to implement the output control enhancement technology based on the signal of the unit master as shown in FIG. to be.

That is, the step (S31) will be described in more detail as follows.

The rate of change of output at the power plant is very important. This is because it is possible to contribute to the stabilization of the system frequency by quickly following the target value at the request of power supply or when performing the Governor free operation. Since the rate of change in output per minute is used as the basic data to calculate the rate, it is necessary to secure the rate of change in output over a certain level.

In coal-fired power plants, it takes a lot of time to pulverize, transport, and burn the fuel, which makes it difficult to rapidly increase or decrease output due to the slow response of the process. Damage to the boiler structure or deterioration of life due to overshoot of the generated fuel is accompanied.

Therefore, it is necessary to design the boiler so that it can rapidly increase or decrease the power without large transient phenomenon, and it should be equipped with an automatic control system to support it.

The present invention implements an output control enhancement technique using an advanced controller (APC) to configure a controller using a model to overcome the difficulties caused when using a conventional controller. The output control improvement technique of this invention uses the following method.

Dynamic feedforward (model-based kicker) is used to enhance the fuel's upstream behavior. The integral operation of the transition is slowed down and the steam pressure setpoint is corrected by pressure prediction.

The advantages of using the modelbase output control enhancement technique are as follows. First, the pressure fluctuations during the load fluctuation transition period are reduced, and rapid stability can be obtained after the end of the transition period.

On the other hand, in order to predictively control a boiler with a slow response, the model base transfer function generates a slow feed forward from the model base transfer function generator (ARX) 143 according to the variation of the output request signal (ULD) supplied from the unit master. The generator 144 generates a fast feed forward, respectively.

These two dynamic preceding signals are added to the fuzzy logic 145 at an appropriate ratio according to the absolute difference between the final output target value and the current set value (ABS: 142) to be the preceding signal of the boiler master.

The model-base transfer function generator 147 and the model-base transfer function generator 148 predict the steam pressure change according to the turbine master and boiler master signals, respectively, and act as the setpoints in the proportional integral derivative controller block 151, respectively. And the actual steam pressure is compared to generate a boiler master signal that controls the fuel, air and water supply throughout the boiler.

In the transient period, the pressure error can excessively wind up the integrator output from the proportional integral derivative controller (PID), thereby slowing the operation by modifying the setpoint using a pressure prediction model, instead of using feedforward ( The feedforward signal is processed by using the transfer function generator (ARX) algorithm and the fuzzy function to reduce the pressure error and sent out to the output of the proportional integral derivative controller. In other words, in the transitional period, the main strategy is to use accurate predictive control rather than the correction function of the proportional integral derivative controller. The fuel control signal using the model enters a lot at first, but you can see that it is stable.

The setting of the fuzzy algorithm is programmed to be controlled by the difference between the output final target value and the current output.

Since the turbine control is very fast in response, the generator output prediction is performed according to the boiler master change through the transfer function generator (ARX) 146, and the turbine valve is controlled to control the generator output with the proportional integral controller 150 according to this prediction set value. The turbine master signal 154 to adjust is output.

There are two types of models that can be used in the transfer function generator, but the empirical model is used in this technology. To calculate the model, the advanced controller (APC) tool kit of the digital controller is used. This allows simple design and input into the controller without complicated calculations.

In the physical model, a structural model using physics and thermodynamics is usually expressed as a differential equation, and in an empirical model, a model obtained by using input and output signals obtained from actual plant operation is used in an advanced controller.

The transfer function of the model obtained through the simulation of a 1000MW supercritical pressure coal power plant is shown in Equation 1.

On the other hand, the terms used in the present invention are defined as follows.

Function block is a symbol that has functions such as automatic, manual mode conversion, proportional derivative controller starting from arithmetic operation, and internal parameter is used to input the function limit value of function block, fixed function, proportional integral setting value, etc. It is variable, and the control algorithm is control logic to execute the controller of unit master, turbine master, boiler master, etc. according to the characteristics and functions of power generation facilities such as boiler and turbine, and the process proceeds according to the setting value. Situation, overshoot is, for example, increasing the fuel from 50% to 100%, increasing from 50% to 100%, rather than staying constant at 100%, going up to 105% and going back to 100% The rate of change is the rate of change of generator output (electrical output) over time, and the rate of change that must be observed for each power plant is determined by the government notice. Reflected in electricity prices settlement said, and follow-up system load is when the amount of electricity your home or plant growth are be asked to produce more electricity through the power exchange. At this time, in case of sudden change, the load should be able to produce more electricity according to the fixed time (output change rate).

In addition, the frequency stability of the system changes when the load of the system is poor, resulting in a decrease in the quality of electricity and in the quality of precision industrial products. In recent years, in modern control technology, the controller is made by constructing these functions as a model, making the controller simple and convenient when adjusting the controller to the characteristics of the power plant site.

USC is Ultra Super Critical, super supercritical pressure, Redundant Remote Targets: Remote power request signal of power exchange, Redundant is composed of several so that there is no problem in signal transmission even if one problem occurs, Remode Interface: Power exchange APS is an automatic plant start-up / shut-down, a load target is a power production setpoint generated by an operator or an APS, and an operator high / low limit set. The upper limit / lower limit of sudden power setpoint change, Actual MW is the power demand generated by the actual consumption of electricity at home, factory, etc., RB is Run-Back, output reduction to the target, RU is Run-Up, slightly RD is Run-Down, a little output deceleration, Frequency Control is for frequency control, 60Hz, UMC is Unit Master Control, TP is Throttle Pressure, Boiler main steam pressure, APC is Advanced Process Control, URO is Unit Response Optimizer, Power Plant Response Optimizer, ABS is absolute value, ARX is function block for model input, Fuzzy Block is ARX Output is selected by section, PID is proportional integral controller, LAG is time delay, MWe is MW Error which is the deviation between power demand signal and actual usage, TPe is Throttle Pressure Error, Pressure SP Program is pressure Setpoint Program, FF Program is Feedforward Program, STe is Superheater Temperature Error, Main Steam Temperature Deviation, M / A Station is Maual / Automatic Station, Manual, Automatic Mode Selection Function, BM is Boiler Master, KdF is frequency error and Delay Compensation is delay compensation.

In the detailed description of the present invention described above with reference to the preferred embodiment of the present invention, the scope of protection of the present invention is not limited to the above embodiment, and those skilled in the art of the present invention It will be understood that various modifications and changes can be made in the present invention without departing from the spirit and scope of the invention.

1 is a block diagram illustrating a control method for improving power plant output control stability by boiler and turbine response delay compensation according to an embodiment of the present invention.

FIG. 2 is a block diagram showing unit master control in a control method for improving power plant output control stability by the delay response of the boiler and turbine.

3 is a block diagram showing a boiler master control in the power plant output control stability enhancement control method by the boiler and turbine response delay compensation.

4 is a block diagram illustrating the turbine master control in the power plant output control stability improvement control method by the boiler and turbine response delay compensation.

FIG. 5 is a block diagram illustrating a boiler master dynamic response compensation control in a power plant output control stability improvement control method by the boiler and turbine response delay compensation.

6 is a graph showing a linear output response by the dynamic pressure compensator in the power plant output control stability improvement control method by the boiler and turbine response delay compensation.

7 is a schematic block diagram of the entire control logic in the power plant output control stability improvement control method by the boiler and turbine response delay compensation.

8 is an operation control monitoring screen in the power plant output control stability improvement control method by the response delay compensation of the boiler and turbine.

FIG. 9 is a graph illustrating an improvement trend of output control performance in a control method of improving power plant output control stability by the response delay compensation of the boiler and turbine.

FIG. 10 is a photograph illustrating major control variable trends when a power plant output fluctuates in a control method for improving power plant output control stability due to the response delay compensation of the boiler and turbine.

FIG. 11 is a block diagram illustrating a control method for improving power plant output control stability by boiler and turbine response delay compensation according to another embodiment of the present invention.

12 is a block diagram showing a boiler turbine master control using an advanced controller in the power plant output control stability improvement control method by the boiler and turbine response delay compensation.

13 is a diagram illustrating a high speed and a low speed forward feed in the power plant output control stability improvement control method by the boiler and turbine response delay compensation.

Claims (16)

A) controlling the unit master to change and operate the generator output according to the target output setting of the power plant and the required output change rate; B) controlling the boiler master to supply fuel, water supply and combustion air to the lower boiler auxiliary facilities based on the signal of the unit master; C) controlling the turbine master to control the generator output by adjusting the steam valve of the turbine based on the signal of the unit master; And D) controlling the input according to the dynamic response compensation of the boiler master when the output demand value is changed by the control of the unit master, the boiler master and the turbine master; Control stability improve control method. The method of claim 1, The step B) and step C) is performed at the same time characterized in that the power plant output control stability improvement control method by the response delay compensation of the boiler and turbine. 3. The method of claim 2, Step B) and step C) are cooperatively controlled so as to cooperate with each other to stabilize the steam pressure and temperature of the power plant. The method of claim 1, wherein step A) a) output command by the remote power signal from the power supply command; b) setting a target output through a signal generator during operation of the unit master; c) the upper or lower limit output limit signal of the target output and the signal passing through the selector do not exceed the limit value as an output command; d) tracking the actual output by selecting the actual power output in the selector and disregarding the lower limit output limit signal if it is not cooperative control of the boiler and turbine in the operation mode of the unit master; e) controlling the rate of change of the signal and limiting the rate of change upon output deceleration or output rise or output deceleration to a predetermined target; f) the frequency signal for the frequency following operation is inputted as a frequency error to be added to or subtracted from the unit master signal, so that the output is added or decremented, and a continuous increase or decrease signal is added to the unit master signal at the time of output rise or output deceleration; And g) the generator output is suddenly decelerated and the target transmission signal is transmitted when the boiler auxiliary equipment is partially stopped and supplied as a command signal of the turbine master and the boiler master; Power plant output control stability improvement control method by the boiler and turbine response delay compensation comprising a. The method of claim 3, wherein the step B) is a) output request signal of the unit master is scaled to fit the boiler auxiliary equipment to become a reference signal of the boiler master; And b) selecting a cooperative control mode or a boiler following control mode of the boiler and the turbine and outputting a corresponding result; and controlling the power plant output control stability by controlling the delay response of the boiler and the turbine. The method of claim 5. In selecting the cooperative control mode of the boiler and the turbine in step b), after the steam pressure error is detected in the subtraction block, it is supplied to the proportional integral differential controller to control the steam pressure. Power plant output control stability improvement control method. The method of claim 5. When the boiler following control mode is selected in the step b), the boiler master adjusts the input of the entire boiler due to the main steam pressure error. . The method of claim 3, wherein step C) a) output request signal supplied from said unit master becomes a reference signal of a turbine master; b) compensating for a time delay of a boiler larger than a turbine in calculating the reference signal; And c) selecting a cooperative control mode or a turbine following control mode of the boiler and the turbine according to the time delay compensation; and improving the power plant output control stability by controlling the response delay of the boiler and the turbine. The method of claim 8, When selecting the cooperative control mode of the boiler and turbine in the step c), after the steam pressure error is detected in the subtraction block is supplied to the proportional integral derivative controller to control the output by the response delay compensation of the boiler and turbine Power plant output control stability improvement control method. The method of claim 8. When the turbine following control mode is selected in the step c), the turbine master adjusts the operation of the turbine valve by the main steam pressure error. . The method according to claim 9 or 10, A frequency error of the turbine and the generator speed deviation is scaled for the frequency control operation during step C), and the turbine master signal of the cooperative control mode or the turbine following control mode of the boiler and the turbine is added or subtracted. Power plant output control stability improvement control method by turbine response delay compensation. The method of claim 1, wherein the step D) a) output request value If a power plant output request signal changes, generating a signal in a direction which helps the output change in the differentiator and adding the signal to the boiler master; And b) the differential signal is programmed in the function generator so that the magnitude is adjusted according to the output interval. The method of claim 12, wherein the step D) Filtering is required as the first delay of the differential signal, the delay integer is programmed according to the output section of the function generator, and when the output ramp up is completed, the reduction of the differential signal is required and the ratio is applied to the output section of the function generator. Power plant output control stability improvement control method by boiler and turbine response delay compensation characterized in that the programming according to. The method of claim 13, The control method for improving power plant output control stability by boiler and turbine response delay compensation, characterized in that for generating a compensation signal by exponentially appearing the signal change instead of the change rate limiter that increases or decreases at a constant rate during the dynamic response. A) controlling the unit master to change and operate the generator output according to the target output setting of the power plant and the required output change rate; B) controlling the boiler and turbine master using an advanced controller to implement an output control enhancement technique based on the signal of the unit master; And C) controlling the input according to the dynamic response compensation of the boiler master when the output required value is changed by the control of the unit master, the boiler master and the turbine master; Control stability improve control method. The method of claim 15, wherein the step B), a) generating a stable preceding signal and a sharp preceding signal in a model-base transfer function generator in accordance with a change in the output request signal supplied from the unit master to predictively control a boiler having a late response; b) adding the stable leading signal and the dynamic leading signal, which is a steep leading signal, by adding a ratio in a fuzzy logic according to a difference between a final output target value and a current set value to be a leading signal of a boiler master; c) predicting the steam pressure change in accordance with the turbine master and boiler master signals in the model-based transfer function generator; d) applying a setpoint to a proportional integral derivative controller in accordance with said vapor pressure prediction; And e) generating a boiler master signal for controlling the fuel, air and water supply of the entire boiler by comparing the predicted set value with the actual steam pressure; Improve control method.

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