CN102946224B - Thermal power unit power prediction control system for ensuring safety and stability of sending-end electric grid - Google Patents
Thermal power unit power prediction control system for ensuring safety and stability of sending-end electric grid Download PDFInfo
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Abstract
The invention discloses a thermal power unit power prediction control system for ensuring the safety and stability of a sending-end electric grid. The thermal power unit power prediction control system comprises a high-frequency emergency state and prediction unit (1), a speed regulator prediction control unit (2) and a boiler prediction control unit (3), wherein the high-frequency emergency state and prediction unit (1) is electrically connected with the speed regulator prediction control unit (2) and the boiler prediction control unit (3); the speed regulator prediction control unit (2) is electrically connected with a servo of a speed regulating mechanism; and the boiler prediction control unit (3) is electrically connected with a boiler and an auxiliary machinery. According to the invention, when the sending-end electric grid is split, the power naturally distributed to a unit by the sending-end electric grid is measured, unit prediction power setting for keeping isolated grid balance and equitable distribution is obtained through conversion, fast and accurate control regulation is carried out through a unit prediction control method on a steam turbine and the boiler, so that the dynamic energy balance among the boiler, the steam turbine and the sending-end electric grid is effectively ensured, the problem of oscillation of OPC (Overspeed Protection Control) is solved, and the high-frequency stable level of the sending-end electric grid and the safety of the unit are greatly enhanced.
Description
Technical Field
The invention relates to the field of power grid safety control and the field of thermal control of a steam turbine generator unit, in particular to a thermal power unit power prediction control system for guaranteeing the safety and stability of a power grid at a transmitting end.
Background
The power generated by a steam turbine generator unit in a transmission end power grid is transmitted to a receiving end power grid through the power grid, if a load circuit trips under the fault disconnection or isolated grid state of the transmission end power grid and the receiving end power grid, the power of the steam turbine generator exceeds the load, the power grid frequency and the unit rotating speed are increased, if the power unbalance degree of the power grid is large, the safety of a steam turbine blade is endangered by the overhigh rotating speed, and the generator tripping is caused, so that the high-frequency instability of the power grid is caused.
Under the high-frequency state of a power grid, Overspeed Protection (OPC) of the steam turbine generator unit can act, the steam valve is closed to quickly reduce the output of the unit, and the frequency of the power grid can be quickly returned to normal so as to ensure the safety of the steam turbine. However, when the OPC action is finished, the control of the valve is switched back to the primary frequency modulation and power control of the governor, and at this time, the governor loses the correct control setting and still maintains the power setting before the disconnection, which largely exceeds the isolated grid load level, so that the unit starts to increase the output again, and the grid returns to the high-frequency state again, thereby causing the OPC action again. The process is repeated in a circulating mode, so that the frequency of a power grid and the power of a unit fluctuate periodically and in a saw-tooth shape, and finally the isolated grid loses power in a large area. This condition occurs many times in a domestic grid disconnection accident.
Research shows that under the technical conditions specified by the current standard, regulation and normative document, the high-frequency stability margin of the thermal power unit speed regulating system is very low, and when the power of the thermal power unit exceeds about 12% of the load power (namely the unbalance rate of the power grid) during splitting, the isolated grid frequency cannot be stable. Especially, a power grid safety and stability control system and a high-frequency generator tripping automatic device of a sending end power grid consisting of a large machine and a small machine are difficult to control the unbalance rate of an isolated grid within 12%, the high-frequency stability cannot be guaranteed, and the safe, stable and reliable operation of the sending end power grid and a unit is seriously influenced.
The energy regulation process of the boiler is slower than the power regulation process of the steam turbine, and the power regulation process of the steam turbine is slower than the electromechanical transient process of the power grid. When a power grid at a sending end is disconnected, the power adjustment process of the steam turbine is slow, so that the rotating speed is overhigh, and the safety problem of a steam turbine blade is caused; the delay of the energy adjustment process of the boiler leads to the over-high pressure of the main steam, causes the action of the safety door and easily leads to the machine set cutting machine. Therefore, accelerating the adjustment process of the steam turbine and the boiler is the key for solving the problem of high frequency stability when the power grid at the sending end is disconnected.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: the thermal power generating unit power prediction control system for guaranteeing the safety and stability of the power grid at the sending end is provided, so that the problem of safety of blades of a steam turbine caused by overhigh rotating speed due to the delay of the power adjustment process of the steam turbine when the power grid at the sending end is disconnected is solved; the delay of the energy adjustment process of the boiler leads to the over-high pressure of the main steam, causes the action of the safety door, and easily leads to the problems of machine set cutting and the like.
The technical scheme of the invention is as follows:
thermal power unit power predictive control system of guarantee sending end electric wire netting safety and stability includes:
the high-frequency emergency state and prediction unit judges whether the power grid is in a high-frequency emergency state according to the input signal, outputs a quick power drop-back signal, a power control target, a unit power setting and a power change rate in the high-frequency emergency state, and is electrically connected with the speed regulator prediction control unit and the boiler prediction control unit; the input signals comprise unit power, rotating speed and overspeed protection action signals.
The speed regulator prediction control unit is used for carrying out PID power control according to the high-frequency emergency state and the set power setting sent by the prediction unit in the high-frequency emergency state, readjusting the integral output state to the predicted power setting during the sending period of an overspeed protection OPC action signal, canceling or reducing the limitation of an adjusting instruction speed-limiting link during the sending period of a quick power drop-back signal, and sending an output high-pressure valve instruction to a servo of a speed regulating mechanism to be electrically connected with the servo of the speed regulating mechanism;
the boiler prediction control unit automatically converts the control mode of the analog quantity control system MCS into a boiler following BF mode according to the high-frequency emergency state and a quick power drop-back signal sent by the prediction unit in the high-frequency emergency state, is connected with a coal mill according to the power change rate, accelerates the response of the fuel supply process, controls the opening and closing of the electric pressure relief valve PCV when the quick power drop-back signal is sent out, controls the bypass BP according to the power change rate, and is electrically connected with the boiler and an auxiliary machine;
the high frequency emergency and prediction unit includes:
the high-frequency emergency state judging module is used for carrying out logic operation according to the overspeed protection OPC action signal, the rotating speed signal and the unit offline signal, judging whether the system is in a high-frequency emergency state or not and electrically connected with the emergency state widening module;
the emergency state widening module widens according to the high-frequency emergency state signal sent by the high-frequency emergency state judging module and according to set time, outputs a quick-fall power signal and is electrically connected with the power change rate memory, the power setting memory and the monitoring system;
the generator power, frequency and voltage acquisition module is used for acquiring the generator power, frequency and voltage and is electrically connected with the power, frequency and voltage factor correction module;
the power, frequency and voltage factor correction module corrects the power of the generator according to the frequency and voltage factor of the load of the power grid, so that the power of the generator measured during the OPC action is balanced with the load in total amount, one path of output of the power, frequency and voltage factor correction module is electrically connected with the power change rate memory after passing through the delayer, the other path of output is directly electrically connected with the power change rate memory, and the other path of output is electrically connected with the power setting memory;
the power change rate memory is triggered by the rising edge of the fast fall-back power signal FB, calculates the ratio of the power of the generator during the splitting to the power of the generator before the splitting, writes the power into the power change rate memory and keeps the power;
and the power setting memory writes the unit power measured at the moment into the memory at the moment when the emergency state broadening module outputs the rising edge, keeps the unit power as the unit power setting output during the emergency state broadening period, and keeps the unit power setting memory in the emergency state all the time.
The speed regulator prediction control unit comprises an integral link module with a resettable state and an emergency state speed limit exit module, and the integral link module with the resettable state is connected with the emergency state speed limit exit module through a third adder.
The boiler prediction control unit includes:
the power following control mode conversion module: setting the control mode of the analog quantity control system MCS to be a boiler following mode according to the high-frequency emergency state and the rapid fall-back signal sent by the prediction unit, and electrically connecting the control mode with the first routing switch;
the boiler following controller output tracking module enables the boiler following controller to form a closed loop for tracking the pressure of a main valve in an analog quantity control system control mode, keeps the correct output state of PID, avoids the occurrence of jump of the output state when switching to the boiler following control mode in a high-frequency emergency state, and is electrically connected with the first adder-subtractor;
and the coal mill cutting and fuel distribution module triggers and starts coal mill cutting logic at the starting moment of the high-frequency emergency state quantity according to the power change rate, cuts the corresponding number of coal mills closest to the power change rate, accelerates the control response speed of fuel, and relieves the problem of high main steam pressure caused by slow fuel adjustment.
The thermal power generating unit power prediction control system for guaranteeing the safety and stability of the transmission end power grid measures the active power of a generator at the moment of Overspeed Protection (OPC) action, and the active power is used as predicted unit power setting after being corrected and calculated to control the unit power.
During the period of sending an Overspeed Protection (OPC) action signal, the output state of an integral link in power PID control of a speed regulator prediction control unit is adjusted to a conversion value of a predicted power setting, and the conversion value of the predicted power setting is a corrected and converted replacement value of the output state of the integral link of the generator active power measured at the initial moment of the OPC action.
The invention has the beneficial effects that:
according to the method, after a power grid at a sending end is disconnected, the isolated power flow can be changed immediately, the power of each power plant in the isolated power is redistributed naturally, and the naturally distributed power at the initial moment in a high-frequency emergency state is used as predicted power setting after being corrected by frequency and voltage factors, so that the method has one characteristic. The characteristic ensures that each power plant in the power grid coordinates and reasonably distributes the adjusting task in a dispersed and independent control mode when the power grid at the sending end is disconnected, so that the power of the power grid is balanced, and the steady-state frequency difference existing in the conventional control system is reduced; the system and the control system of the stable cutting machine can be independently controlled without communication and can naturally keep coordination.
The invention adopts a predictive control technology, realizes five coordination under the conditions of disconnection of a power grid at a transmitting end, load shedding of an isolated grid and load shedding of a unit, effectively improves the safety and stability performance of the power grid at the transmitting end and the unit, and particularly comprises the following steps:
the coordination of the Opc primary frequency modulation and the power control is realized; the safety of the turbine blades is effectively guaranteed, and meanwhile, the stability of a speed regulating system and a power grid is improved.
The coordination between the speed regulating system and the boiler control, namely the coordination between the power and the fuel steam pressure control, is realized, the conflict generated by the difference of the speed between the steam turbine and the boiler control is overcome, the action of the safety door caused by overhigh steam pressure is effectively prevented, and the safety and reliability of the unit are improved.
Coordination among the units of the power plants in the isolated network is realized, the units in the isolated network reasonably share power adjustment tasks after load shedding of the isolated network, the units are adjusted according to respective settings, power robbery and conflict caused by different unit characteristics and parameters can not occur, and oscillation formed from the power adjustment tasks is avoided.
The balance and coordination of the unit power control and the isolated network load are realized, the set sum of the power predicted by each unit in the isolated network is equal to the isolated network load, and the power network frequency can return to the rated frequency after each unit is adjusted.
The coordination of the unit control and the power grid safety and stability tripping measures is realized, the unit control and the power grid safety and stability tripping measures can be adjusted and operated respectively without communication connection and cooperation, and the coordination of the unit control and the power grid safety and stability tripping measures keeps natural coordination.
The invention uses the units as units to carry out the dispersed independent control, and the units, the units and the stable cutting machine are automatically coordinated with each other without communication and connection. The distribution coordination control technology has strong adaptability to the splitting of a power grid at a transmitting end caused by unpredictable property faults and the high-frequency stability of an isolated network under disaster conditions,
the invention can greatly improve the high-frequency stability level of the power grid at the transmitting end, improve the firmness of the power grid under unpredictable faults and the disaster resistance of the power grid under disaster conditions, improve the safety of the unit and have remarkable social benefit
The invention effectively solves the problem of frequency safety and stability of large machine and small network by using low-cost control technology, and after eliminating the restriction factor, the power grid can access the large machine set into the 220kV regional power grid during planning, and send out through 500kV contact transmission after load is absorbed, thereby eliminating the circuitous load current, greatly reducing the electric energy loss of the power transmission network, and being an energy-saving and emission-reducing measure with less investment and great effect.
The invention solves the key problem that a large-scale unit is accessed into a 220kV regional power grid, after the large-scale unit is accessed into the 220kV regional power grid, the generated power consumes the 220kV regional power grid load, the power transmitted into a 500kV power grid is greatly reduced, the capacity of 500kV power transmission and transformation facilities is correspondingly reduced, the huge investment of primary equipment of the 500kV power grid can be correspondingly saved, and the economic benefit is obvious.
The invention utilizes the natural distribution characteristic of the unit power after the splitting of the sending end power grid, does not need to build a centralized control system, and controls in a decentralized control mode, and has the characteristics of simple implementation technology and low cost, and the invention does not conflict with the current relevant standards, specifications and regulations in China, is beneficial to development and modification in the prior art, is beneficial to popularization, and solves the problems of overhigh rotating speed and safety of turbine blades caused by the delay of the power adjustment process of the turbine when the splitting of the sending end power grid; the delay of the energy adjustment process of the boiler leads to the over-high pressure of the main steam, causes the action of the safety door, and easily leads to the problems of machine set cutting and the like.
Description of the drawings:
FIG. 1 is a block diagram of the components of the control units of the present invention;
FIG. 2 is a block diagram of a high frequency emergency and prediction unit according to the present invention;
FIG. 3 is a schematic diagram of a governor predictive control unit module of the present invention;
FIG. 4 is a schematic diagram of a boiler predictive control unit module according to the present invention;
FIG. 5 is a simulation diagram of a conventional speed control system when the power grid throws 40% of load;
FIG. 6 is a simulation of the control system of the present invention when 40% of the unit capacity is shed.
The specific implementation mode is as follows:
the principle and the property of isolated grid unit power distribution when a power grid at a sending end is disconnected are as follows:
when a power grid at a sending end is disconnected, isolated grid tide is changed immediately, and the generated power of a unit is redistributed.
When a sending-end power grid is disconnected, electromagnetic synchronous torques of all the generators in the isolated power grid are drawn into each other, all the units in the power grid can keep synchronous, the rotating speed rising speeds are basically consistent, and the time of reaching OPC (optical proximity correction) action (3090 rpm) is basically the same, so that the rotating speeds of the units in the isolated power grid can be assumed to be consistent. In the period after grid splitting and before OPC action, because of time delay of valve servo, pipeline and cylinder, it can be assumed that the mechanical power of the prime mover is not changed before OPC action; after voltage and frequency effects of the load are ignored, the property of the power distribution of the group at the splitting time of the sending-end power grid under the assumed state can be obtained.
According to the principle that power flow of a power grid keeps balance at the same time, after the power grid is split, the time of the unit in OPC action is the same, and the generated power measured by all the units in the isolated power grid at the moment is equal to the isolated power grid load and is called as property 1.
Property 1 indicates that the generated power of all units in the grid, measured at the time of OPC operation, is adjusted individually as the power setting of the governor system, so that the generated power of the grid can be equalized to the load, and the grid frequency can be returned to the rated value.
[0001] M generator sets are arranged in the isolated network, and the following per unit formula can be deduced according to the electromechanical principle
Wherein,is the power generation power before the i-th unit in the isolated network is decomposedAnd power after splittingThe difference between the difference of the two phases,for the power generating capacity of the unit,and the time constant of the rotational inertia of the unit is obtained.The difference between the total power of power generation before the isolated network is disconnected and the isolated network load power after the isolated network is disconnected.
<2>The formula shows that: after the splitting, during OPC operation, the generated power of the unit is measured as the predicted unit power settingWhen each unit is adjusted according to the predicted power setting, the total power of the isolated network imbalanceThe task of adjustment of (2) is distributed to the units in the network in proportion to the product of the capacity of each unit and the time constant of the moment of inertia of the unit, this property being called property 2.
It is noted that the moment of inertia time constants of the large hydroelectric generating set and the thermal power generating set are not greatly different, and the total power of the isolated network imbalanceSubstantially according to the ratio of the unit capacity to the capacityThe case is distributed to each machine set. The regulation of the power of the prime mover of the unit is carried out according to the nature of natural distribution of the generated power after the power grid is split, and the regulation is fair and reasonable.
Property 2 indicates that the generated power of all units in the grid, measured at the time of OPC operation, is individually controlled and adjusted as the power setting of the governor system, and the adjustment amount of each unit is reasonably distributed. The property 1 and the property 2 jointly indicate that the unit sets can be in communication connection with each other, and coordination control can be realized in a high-frequency state of a power grid.
Load shedding powerTime constant of moment of inertiaRotational speed of the motorAnd its speed of riseThe relationship with OPC action time t can be derived as follows:
<3>
in the formula, all variables are per unit value
The action time of OPC rising to 3090rpm is as follows:
the rotational inertia time constant of 300MW or more thermal power generating unit is more than 8.4 seconds, and power is generated in the unitIn the case of total power draw-off, i.e.=1, the OPC operation time can be calculated as 0.27 seconds.
And the whole group of action time controlled by the section of the power grid safety and stability control system is less than or equal to 0.2 second, so that the whole group of action time of the power grid safety and stability control system is less than the OPC action time of the thermal power generating unit.
And after splitting, if the safety and stability control system is switched by an undercutting strategy, naturally distributing the isolated network unit power again after the safety and stability control system is switched, after the distribution is finished, performing OPC (optical proximity correction) on the power, and keeping the property 1 and the property 1 of the measured unit power generation power at the moment. Therefore, whether the stability control system is tripping or not, the generated power measured during the OPC action is always correct as the power setting of the governor, which is called property 1.
The property 3 shows that the safety and stability control system and the unit power control system can be respectively and dispersedly regulated and controlled without communication connection and can be mutually coordinated.
The above properties are derived from assumptions, and in an actual grid, the situation may deviate from the above properties, and according to simulation calculations, the properties of the actual grid are as follows:
when the isolated network formed by the single machine or the single-plant unit of the same type is disconnected in various faults, the power of the unit cannot fluctuate, the predicted power setting accords with three properties, and the deviation degree is small.
The isolated network fault-free tripping operation formed by different types of units of multiple plants is disconnected, the power fluctuation of the units is extremely small, the predicted power setting accords with three properties, and the deviation degree is very small.
The method is characterized in that a power grid at a transmitting end formed by multiple plants is disconnected due to three-phase grounding, phase and single-phase permanent faults, isolated grid units fluctuate mutually, if the isolated grid load shedding rate (unbalance rate) is greater than 50%, under a few conditions, the predicted power setting deviation property 2 is adopted, the phenomenon of uneven distribution of unit adjusting tasks occurs, however, the unit power setting and the isolated grid load are balanced, the deviation property 1 is small, the control system can ensure high-frequency stability, only the phenomenon that the distribution of the unit adjusting tasks is not even slightly occurs, in the actual power grid operation, the situation is rare, the power balance problem is considered when the power grid is planned and operated, and multiple isolated grids with load shedding rates greater than 50% basically do not exist.
Embodiments of the invention
A thermal power generating unit power prediction control system for guaranteeing safety and stability of a transmission end power grid comprises (as shown in figure 1):
the high-frequency emergency state and prediction unit 1 judges whether a power grid is in a high-frequency emergency state or not according to an input signal, outputs a rapid power drop-back signal, a power control target, a unit power setting and a power change rate in the high-frequency emergency state, is in electric signal connection with the speed regulator prediction control unit 2 and the boiler prediction control unit 3, and is connected with an automatic power generation system (AGC) through a monitoring system to carry out information interaction with the high-frequency emergency state and prediction unit 1.
The high-frequency emergency state and prediction unit 1 has the functions of quickly, accurately and reliably predicting the set power setting which keeps balance with the isolated network load and providing accurate prediction control quantity for quickly adjusting the steam pressure, the fuel and the air quantity. Judging whether a power grid is in a high-frequency emergency state or not according to signals including an Overspeed Protection (OPC) action signal, widening time of the emergency state, and outputting a rapid power drop-back signal; measuring the power of the unit as the power of the unit after the power grid is disconnected at the time of an Overspeed Protection (OPC) action by utilizing the natural distribution of the power grid to the power of the unit at the initial stage of the disconnection, and outputting the power of the unit as the predicted power setting in a high-frequency emergency state to a speed regulator prediction control unit after the power of the unit is corrected by a load frequency factor and a voltage factor; and calculating the adjustment quantity such as the power change rate and the like and outputting the adjustment quantity to a boiler prediction control unit.
The high frequency emergency and prediction unit comprises (see fig. 2):
the high-frequency emergency state judging module is used for carrying out logical operation according to the overspeed protection OPC action signal, the rotating speed signal and the unit offline signal, judging whether the system is in a high-frequency emergency state or not and is in signal connection with the emergency state widening module; the basic processing logic is: the method is characterized in that logic and operation are carried out according to an action signal sent by overspeed protection OPC, a rotating speed out-of-limit signal (output after comparison operation of the rotating speed signal and a rotating speed setting signal omega set) and a logical non-signal of unit off-line, the rotating speed out-of-limit signal plays a role in preventing false action as a judging condition of the unit in a high-frequency state, and two possible high-frequency fault modes can be judged by a high-frequency emergency state judging basic logic: a. splitting a power grid at a sending end, and enabling a unit to be in an isolated network in a high-frequency state; b. and tripping the machine set in the isolated network and the heavy-load line. The present module contains only basic logic, but the present invention is not limited to logic combination with other signals, such as: the unit does not participate in high-frequency regulation under the condition of sliding pressure operation, and a sliding pressure state signal can be accessed to the module after being negated.
The emergency state widening module widens according to set time according to the high-frequency emergency state signal sent by the high-frequency emergency state judging module, outputs the signal as a fast-fall power signal, is connected with the power change rate memory, the power setting memory and the monitoring system through leads, widens according to the high-frequency emergency state signal sent by the high-frequency emergency state judging module according to the set time, and outputs the signal as a fast-fall power signal FB (fast Back) which represents an emergency event of fast returning to set power of the machine furnace control system and is an event signal which is greatly different from RB (run Back) and FCB (fast Cut Back). FB differs from RB in that it does not down-regulate power or energy at a certain rate or time sequence, but quickly adjusts the unit output at one time according to the predicted signal; the difference between the FCB and the FCB is that the FCB throws out all loads for supplying power to a power grid, and the FB is that a unit is quickly adjusted to a predicted set power to supply power to the power grid. The high-frequency emergency state (namely the process in the broadening time of the fast buck power signal FB) refers to a dynamic process of changing the isolated network frequency from high frequency to a stable state, the broadening time is set to be 200-300 s, and for a thermal power generating unit, the period comprises the dynamic process of adjusting the rotating speed and power of a steam turbine and comprises a first fluctuation adjusting process which is critical to the steam pressure of a boiler;
the generator power, frequency and voltage acquisition module is used for acquiring the generator power, frequency and voltage, is in signal connection with the power, frequency and voltage factor correction module, and is used for acquiring the generator power obtained by sampling the power at the generator end and obtaining the power of the generator before splitting in a mode that a delayer delays for 5-10 seconds;
the power, frequency and voltage factor correction module corrects the power of the generator according to the frequency and voltage factor of the load of the power grid, so that the power of the generator measured during the OPC action is balanced with the load in total amount, and one output path of the module passes through the time delay unit and is connected with the power change rate memory through signals to output power P before disconnection-NOne path is directly connected with a power change rate memory signal to output power P during splitting, and the other path is connected with a power setting memory signal to output power P during splitting (emergency);
the power change rate memory is triggered by the rising edge of the fast fall-back power signal FB to calculate the power P of the generator during the splitting and the power P of the generator before the splitting-NThe ratio, write to memory and hold;
the power setting memory writes the unit power P measured at the time of the 'emergency' state into the memory at the time of the rising edge output by the emergency state broadening module, and holds the unit power P as the set power setting output during the emergency state broadening period. If the monitoring is released from the emergency state, the memory writes the set power setting sent by the monitoring system. The monitored incoming power setting may be from an automatic generation system (AGC) with a "remote" nature of the power setting or may be written by plant operator operations with a "local" nature of the power setting.
Governor predictive control unit 2 (see fig. 3):
in a high-frequency emergency state, PID power control is carried out according to the high-frequency emergency state and power setting sent by the prediction unit 1, the integral output state is readjusted to be predicted power setting during the sending period of an overspeed protection OPC action signal, the limitation of a speed limiting link of an adjusting instruction is cancelled or reduced during the sending period of a quick power drop signal, and the output high-pressure valve instruction is sent to a servo of a speed regulating mechanism and is connected with a servo lead of the speed regulating mechanism; the speed regulator prediction control unit 2 comprises an integral link module 3.1 with a resettable state and an emergency state speed limit exit module 3.2, wherein the integral link module 3.1 with the resettable state is connected with the emergency state speed limit exit module 3.2 through a third adder 3.5.
In the normal state of the power grid, the unit carries out conventional PID regulation, and in the high-frequency emergency state after disconnection, the power setting of the unit is switched to the predicted power setting after disconnection of the power grid by the high-frequency emergency state and prediction unit 1. During the period when an Overspeed Protection (OPC) action signal is sent, namely the high-pressure valve control authority is transferred to OPC, and the governor predictive control unit loses the high-pressure valve control authority, the governor predictive control unit utilizes the period to carry out state conversion, and converts the output state of the integral link into predicted power setting. After the over-speed protection (OPC) action signal is finished, when the control right of the high-pressure valve is transferred to the speed regulator predictive control unit, the output state of the integral link of the PID of the speed regulator predictive control unit is converted into the predicted power setting. During the period of sending the rapid power drop-back signal, the speed regulator predictive control unit cancels or reduces the limitation of the speed-limiting link of the regulating instruction so as to adapt to the great change of the correct regulating instruction. The unit has the functions of solving the conflict of Overspeed Protection (OPC), speed regulator power control and primary frequency modulation, keeping coordination among the three, solving the unstable problem of large-amplitude oscillation of OPC repeated action unit and power grid power, enabling the unit power and the power grid frequency to quickly and stably return to the rated frequency, and ensuring the safety of the unit and the power grid. The unit consists of a primary frequency modulation, a power PID regulator and a speed-limiting and amplitude-limiting link, is constructed in a digital electro-hydraulic speed regulation system (DEH), and is different from a conventional speed regulator in that an integral link in the PID adopts an integral link module 3.1 with a resettable state, and an emergency speed-limiting exit module 3.2. Specifically, the functions of the modules are explained as follows:
the state-resettable integrating link module 3.1 is composed of a state reset switch 3.1.1, a discharge switch 3.1.2, an integrating state reset coefficient 3.1.3, a pure integrating link 3.1.4 and a corresponding control loop. When OPC acts, the state of the signal of the state reset switch 3.1.1 is "T", the power setting signal marked by "Y" is output to the fourth adder-subtractor 3.1.6, the power setting is the predicted power of the machine set after the power grid is disconnected at the moment, and the discharge switch 3.1.2 takes the output signal of the state resettable integral link module 3.1 to form an internal feedback loop. Because the reset coefficient of the integral state is 3.1.3, the feedback loop can adjust the output of 3.2 to be close to 0 within a step length, and at the moment, the output of the pure integral link 3.1.4 is clamped into the predicted power of the unit after the power grid is disconnected. When the OPC exits, the state is F, the discharge switch 3.1.2 cuts off a feedback loop, the output of the state reset switch 3.1.1 is 0, and the output of the integration link 3.2 with the resettable state is the output of a pure integration link, namely the predicted power of a unit after the power grid is disconnected.
The third adder-subtractor takes the output signal of the reset coefficient of the integral state 3.1.3 and the output signal of the second adder-subtractor 3.6 to send to the third adder-subtractor 3.1.5, after subtraction, carries on integral calculation through the integral constant and integral value 1/S3.1.4, and then sends to the fourth adder-subtractor 3.1.6. The fourth adder-subtractor 3.1.6 outputs a signal to a third adder 3.5, the rotating speed, the set power P and the set power are sent to the second adder-subtractor 3.6 together after being subjected to primary frequency modulation for addition and subtraction operation, one path of output is sent to the third adder 3.5 after being amplified by a proportionality constant, one path of output is sent to the third adder 3.5 after being subjected to differential calculation by a differential constant and a differential constant value S, the third adder 3.5 is output to a speed limiting module 3.2.1 after being subjected to addition operation, the third path of output is sent to a Y end of a switch 3.2.2, the speed limiting module 3.2.1 outputs to an N end of the third path of output by the switch 3.2.2 through a fast buck signal FB for triggering, the output is sent to a limiting module 3.3, the output of the limiting module 3.3 and the output after being subjected to primary frequency modulation are sent to the fourth adder together to form valve instruction output after addition operation.
Boiler prediction control unit 3 (see FIG. 4)
In a high-frequency emergency state, automatically converting an analog control system (MCS) control mode into a Boiler Following (BF) mode according to a high-frequency emergency state and a quick power drop-back signal sent by a prediction unit 1, connecting and cutting a coal mill according to a power change rate to quicken the response of a fuel supply process, controlling an electric pressure relief valve (PCV) to open and close when the quick power drop-back signal is sent, controlling a Bypass (BP) according to the power change rate, and electrically connecting the Bypass (BP) with a boiler and an auxiliary machine;
the boiler predictive control unit 3 comprises (see fig. 4): the power following control mode conversion module 4.1: setting the control mode of an analog quantity control system (MCS) to be a boiler following mode according to the high-frequency emergency state and the rapid fall-back signal sent by the prediction unit 1;
the boiler following controller output tracking module 4.2 enables the boiler following controller to form a closed loop for tracking the pressure of a main valve under the control mode of an analog quantity control system, keeps the correct output state of PID, and avoids the jump of the output state when the boiler following controller is switched to the boiler following control mode under the high-frequency emergency state; and the coal mill cutting and fuel distribution module 4.3 is used for triggering and starting a coal mill cutting logic at the starting moment of the high-frequency emergency state quantity according to the power change rate, cutting the corresponding number of the coal mills closest to the power change rate according to an under-cut principle, accelerating the control response speed of fuel and relieving the problem of high main steam pressure caused by slow fuel adjustment.
The working process is as follows: the boiler prediction control unit receives information such as a fast fall back signal FB, temperature reduction water quantity, a high pressure valve position signal, main steam pressure setting TPs, power change rate, main steam pressure and the like, the temperature reduction water quantity and the high pressure valve position signal are sent to two input ends of a first adder 4.7, an output result is sent to one input end of a second adder 4.8 after addition operation, the main steam pressure setting TPs and the output of a second route switch are used as input values of a first adder-subtractor and a second adder-subtractor, the input values are sent to a steam pressure and fuel control PID module 4.6 after subtraction operation, the output of the steam pressure and fuel control PID module 4.6 is sent to one input end of the second adder 4.8, the second adder 4.8 outputs a boiler following control output signal which is sent to an N input end of the second route switch and a Y input end of the first route switch 4.4, the main steam valve pressure is connected to a Y input end of the second route switch, the output of the second adder 4.8 is connected to an N input end of the second route switch, the N input end of the first route switch 4.4 is connected with the output of other control modes, the Y input end is connected with the output boiler following control output signal of the second adder 4.8, the first route switch 4.4 outputs a boiler main control command to the fuel control function module 4.9, the output of the fuel control function module 4.9 is output to the coal mill cutting and fuel distribution module 4.3, and the coal mill cutting and fuel distribution module 4.3 receives a power change rate and a quick return-down signal and outputs a coal mill cutting treatment and fuel control command.
At the moment of an Overspeed Protection (OPC) action, the active power of the generator is measured, and the active power or the active power is calculated after correction and is used as a predicted set power setting to control the set power.
During the period of sending an Overspeed Protection (OPC) action signal, the output state of an integral link in power PID control of a speed regulator is adjusted to a conversion value of a predicted power setting, and the conversion value of the predicted power setting is the active power of a generator measured at the initial moment of the OPC action, is corrected and converted, and then is used as a replacement value of the output state of the integral link.
The integration mode is as follows:
in a distributed control system DCS of a steam turbine generator unit, a high-frequency emergency state and prediction unit 1 and a speed regulator prediction control unit 2 are embedded into a digital electro-hydraulic regulation system (DEH) in the DCS, and a boiler prediction control unit 3 is embedded into an analog quantity control system (MCS).
The high-frequency emergency state and prediction unit is developed into a new hardware module in the digital control panel cabinet in the DEH, and the processing speed of the high-frequency emergency state and prediction unit is the same as that of an overspeed protection module in the DEH.
The speed regulator predicting control unit is developed into a new module to replace the speed regulating control module in the original DEH, or the software of the original module is replaced.
The development mode of the boiler prediction control unit is characterized in that a power following control mode conversion module 4.1 and a boiler following controller output tracking module 4.2 in the figure 4 are embedded into a boiler following mode control loop of an MCS boiler main control part through a DCS signal and function configuration mode; the fuel distribution control section in the fuel subsystem implements a predictive cut coal pulverizer function 4.3 based on the fast fall back signal FB and the power slew rate.
The data acquisition and communication mode, namely the power signal, the rotating speed signal and the OPC action signal input to the high-frequency emergency state and prediction unit are preferably a direct acquisition mode and a special optical fiber communication mode, so that the rapidity and the synchronism of the signal acquisition and communication are ensured. The rest I/O signals are collected and transmitted through a data collection and communication network of the DCS.
Fig. 5 and 6 are: compared with the simulation of the conventional speed regulating system and the control system of the invention when the output of 40 percent of the unit is thrown out, the difference between delta omega and the rotating speed (Hz), the difference between Pe and the generated power (pu), the difference between Pm and the mechanical power (pu) and the difference between the delta omega and the rotating speed (Hz), the Pe and the generated power (pu), the Pm and the mechanical power (pu),
OPC-OPC operation signals (1 is operation, 0 is no operation).
Embodiments are described in this specification, but the invention is not limited to the details of the foregoing exemplary implementations, and may be embodied in other ways without departing from the spirit and essential characteristics thereof, and it is therefore intended that the embodiments be considered as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein and are therefore not to be considered limited to the claims. Furthermore, it is obvious that the word "comprising" does not exclude other elements or modules, which are also protected by the present patent. The parameter values described in the embodiments are examples only and should not be construed as limiting the claims concerned. A plurality of units, modules or means recited in the claims may also be implemented by one unit or module or device by software or hardware. A unit, module or device as recited in the claims may also be implemented by a plurality of units or modules or means in software or hardware.
Claims (5)
1. Thermal power unit power predictive control system of guarantee sending end electric wire netting safety and stability includes:
the high-frequency emergency state and prediction unit (1) judges whether the power grid is in a high-frequency emergency state or not according to the input signal, outputs a quick power drop-back signal, a power control target, a unit power setting and a power change rate in the high-frequency emergency state, and is electrically connected with the speed regulator prediction control unit (2) and the boiler prediction control unit (3); the input signals comprise unit power, rotating speed and overspeed protection action signals;
the speed regulator prediction control unit (2) is used for carrying out PID power control according to the high-frequency emergency state and the set power setting sent by the prediction unit (1) in the high-frequency emergency state, readjusting the integral output state to the predicted power setting during the sending period of an overspeed protection OPC (optical proximity correction) action signal, canceling or reducing the limitation of a speed limiting link of an adjusting instruction during the sending period of a quick power drop-back signal, and sending an output high-pressure valve instruction to a servo of a speed regulating mechanism to be electrically connected with the servo of the speed regulating mechanism;
the boiler prediction control unit (3) automatically converts the control mode of the analog quantity control system MCS into a boiler following BF mode according to the high-frequency emergency state and a quick power drop-back signal sent by the prediction unit (1) in the high-frequency emergency state, and is connected with a coal mill according to the power change rate to quicken the response of the fuel supply process;
the high frequency emergency and prediction unit includes:
the high-frequency emergency state judging module is used for carrying out logic operation according to the overspeed protection OPC action signal, the rotating speed signal and the unit offline signal, judging whether the system is in a high-frequency emergency state or not and electrically connected with the emergency state widening module;
the emergency state broadening module broadens according to the high-frequency emergency state signal sent by the high-frequency emergency state judging module and the set time, outputs a rapid power drop-back signal and is electrically connected with the power change rate memory, the power setting memory and the monitoring system;
the generator power, frequency and voltage acquisition module is used for acquiring the generator power, frequency and voltage and is electrically connected with the power, frequency and voltage factor correction module;
the power, frequency and voltage factor correction module corrects the power of the generator according to the frequency and voltage factor of the load of the power grid, so that the power of the generator measured during the OPC action is balanced with the load in total amount, one path of output of the power, frequency and voltage factor correction module is electrically connected with the power change rate memory after passing through the delayer, the other path of output is directly electrically connected with the power change rate memory, and the other path of output is electrically connected with the power setting memory;
the power change rate memory is triggered by the rising edge of the rapid power drop-back signal, calculates the ratio of the power of the generator during the splitting to the power of the generator before the splitting, writes the power into the power change rate memory and keeps the power;
and the power setting memory writes the unit power measured at the moment into the memory at the moment when the emergency state broadening module outputs the rising edge, keeps the unit power as the unit power setting output during the emergency state broadening period, and keeps the unit power setting memory in the emergency state all the time.
2. The thermal power generating unit power prediction control system for guaranteeing safety and stability of a sending-end power grid according to claim 1, characterized in that: the speed regulator prediction control unit (2) comprises an integral link module (3.1) with a resettable state and an emergency state speed limit exit module (3.2), wherein the integral link module (3.1) with the resettable state is connected with the emergency state speed limit exit module (3.2) through a third adder (3.5).
3. The thermal power generating unit power prediction control system for guaranteeing safety and stability of a sending-end power grid according to claim 1, characterized in that: the boiler prediction control unit (3) comprises:
a "power following" control mode conversion module (4.1): according to the high-frequency emergency state and the rapid power drop-back signal sent by the prediction unit (1), setting the control mode of the analog quantity control system MCS into a boiler following mode, and electrically connecting the boiler following mode with a first route switch (4.4);
the boiler following controller output tracking module (4.2) enables the boiler following controller to form a closed loop for tracking the pressure of a main valve under the control mode of an analog quantity control system, keeps the correct output state of PID, avoids the jump of the output state when the boiler following controller is switched to the boiler following control mode under the high-frequency emergency state, and is electrically connected with the first adder-subtractor (4.5);
and a coal mill cutting and fuel distribution module (4.3) for triggering and starting coal mill cutting logic at the starting moment of the high-frequency emergency state quantity according to the power change rate, cutting the corresponding coal mill quantity closest to the power change rate, accelerating the control response speed of fuel and relieving the problem of high main steam pressure caused by slow fuel adjustment.
4. The thermal power generating unit power prediction control system for guaranteeing safety and stability of a sending-end power grid according to claim 1, characterized in that: the thermal power generating unit power prediction control system for guaranteeing the safety and stability of the power grid at the sending end measures the active power of the generator at the moment of the overspeed protection OPC action, and the active power is used as the predicted unit power setting after being corrected and calculated to control the unit power.
5. The thermal power generating unit power prediction control system for guaranteeing safety and stability of a sending-end power grid according to claim 1, characterized in that: and during the sending period of an overspeed protection OPC action signal, adjusting the output state of an integral link in power PID control of a speed regulator prediction control unit into a conversion value set by predicted power, wherein the conversion value set by the predicted power is the active power of the generator measured at the initial moment of the OPC action, and is corrected and converted to be used as a replacement value of the output state of the integral link.
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| CN104267594A (en) * | 2014-09-11 | 2015-01-07 | 国家电网公司 | Improved load calculation loop method for gas and steam combined cycle unit |
| CN107046289B (en) * | 2016-11-08 | 2020-05-19 | 国电南瑞科技股份有限公司 | Power grid steady-state frequency estimation method considering security control strategy and primary frequency modulation characteristic |
| CN108879791B (en) * | 2017-05-12 | 2021-03-05 | 中国石油化工股份有限公司 | Isolated grid steam-electricity balancing method |
| CN108565854B (en) * | 2018-04-20 | 2024-01-23 | 华北电力科学研究院有限责任公司 | Simulation method and system for reproducing frequency characteristics of power system |
| CN109098788B (en) * | 2018-07-12 | 2021-04-13 | 广西电网有限责任公司电力科学研究院 | Pressurized water reactor nuclear power unit overspeed protection control optimization system and optimization control method |
| CN111525608A (en) * | 2020-04-17 | 2020-08-11 | 广西电网有限责任公司电力科学研究院 | Method and device for realizing power regulation of thermal power generating unit based on rapid load shedding |
| CN113031565B (en) * | 2021-03-08 | 2022-06-21 | 国网湖南省电力有限公司 | Method and system for predicting primary frequency modulation power response performance of thermal power generating unit |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1883094A (en) * | 2003-09-23 | 2006-12-20 | 响应负载有限公司 | Grid stabilising system |
| CN101499766A (en) * | 2008-01-31 | 2009-08-05 | 通用电气公司 | Power generation stabilization control systems and methods |
| CN102588939A (en) * | 2012-03-06 | 2012-07-18 | 山西省电力公司电力科学研究院 | Main boiler control system for large thermal power generating unit |
Family Cites Families (1)
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-
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- 2012-12-10 CN CN201210536379.9A patent/CN102946224B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1883094A (en) * | 2003-09-23 | 2006-12-20 | 响应负载有限公司 | Grid stabilising system |
| CN101499766A (en) * | 2008-01-31 | 2009-08-05 | 通用电气公司 | Power generation stabilization control systems and methods |
| CN102588939A (en) * | 2012-03-06 | 2012-07-18 | 山西省电力公司电力科学研究院 | Main boiler control system for large thermal power generating unit |
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