CN203086401U - Thermal power generating unit power prediction control device capable of guaranteeing safety and stability of export electric network - Google Patents
Thermal power generating unit power prediction control device capable of guaranteeing safety and stability of export electric network Download PDFInfo
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- CN203086401U CN203086401U CN 201220676564 CN201220676564U CN203086401U CN 203086401 U CN203086401 U CN 203086401U CN 201220676564 CN201220676564 CN 201220676564 CN 201220676564 U CN201220676564 U CN 201220676564U CN 203086401 U CN203086401 U CN 203086401U
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Abstract
The thermal power generating unit power prediction control device capable of guaranteeing safety and stability of a export electric network comprising a high frequency emergency state and prediction unit (1), which is electrically connected with a regulator prediction control unit (2) and a boiler prediction control unit (3); the regulator prediction control unit (2) is electrically connected with a server of a speed regulation mechanism; the boiler prediction control unit (3), which is electrically connected with the boiler and an auxiliary machine. During the export electric network splitting, the power, which is distributed to the generating unit by the electric network naturally, can be measured, the generating unit prediction power setting capable of maintaining the balance of the isolated network and guaranteeing the just distribution can be acquired by the conversion. By adopting the generating unit prediction control method, the fast and accurate control adjustment of the steam turbine and the boiler can be carried out, the energy dynamic balance among the boiler, the steam turbine, and the electric network can be effectively guaranteed, the oscillation problem of the overspeed protection (OPC) can be solved, and the high frequency stability level of the export electric network and the safety of the generating unit can be greatly improved.
Description
Technical field
The utility model relates to Power system security control field and turbo generator set heating power control field, refers more particularly to a kind of fired power generating unit power prediction control device that ensures the sending end electricity net safety stable.
Background technology
The generated output of the turbo generator set in the sending end electrical network is sent to the receiving end electrical network by electrical network, if load line tripping under sending end electrical network and receiving end electric network fault off-the-line or lonely net state, turbo generator power has surpassed load, will cause mains frequency and rising rate of rolational speed of generating set, if the uneven degree of grid power is larger, too high rotating speed, with regard to the safety of entail dangers to turbine blade, causes cutting machine, thereby causes the power grid high-frequency unstability.
Under the power grid high-frequency state, turbo generator set overspeed protection (OPC) can be moved, and steam off valve fast reducing unit output can make the mains frequency fast return to normal, to ensure Turbine Safety.But when the OPC release, the control of valve rotates back into again primary frequency modulation and the power of speed regulator and controls, speed regulator has now lost correct control and has set, still remain on power setting before off-the-line, that surpass to a great extent lonely net load level, making unit start again to increase exerts oneself, electrical network turns back to the high frequency state once more, thereby causes that OPC moves again.This process circulation repeatedly, causes mains frequency and the power of the assembling unit to be periodic zigzag fluctuation, finally causes lonely net large tracts of land dead electricity.This situation, repeatedly occur in sending end grid disconnection accident at home.
Research is found, under the technical conditions of current standard, rules and regulatory documents defined, the high frequency stability margin of fired power generating unit governing system is very low, if the overload 12%(unbalanced power supply rate of power of fired power generating unit power during off-the-line) left and right, lonely net frequency just can not stablized.Especially the sending end electrical network that the little net of large machine forms, electricity net safety stable controlling system and high-frequency cutting machine automatics are difficult to lonely net unbalance factor is controlled in 12%, high frequency is stable can not access guarantee, has had a strong impact on the safety and stability reliability service of sending end electrical network and unit.
Because the energy adjusting process of boiler is slower than the power adjustment process of steam turbine, and the power adjustment process of steam turbine is slower than the electromechanical transient process of electrical network.When the sending end grid disconnection, the power adjustment process of steam turbine slow, cause rotating speed too high, causes the turbine blade safety problem; The energy adjusting process of boiler slow, cause main vapour pressure too high, causes the emergency exit action, easily causes unit to cut machine.Therefore, accelerating the adjustment process of steam turbine and boiler, is the key of high frequency stable problem while solving the sending end grid disconnection.
Summary of the invention
The technical problems to be solved in the utility model: a kind of fired power generating unit power prediction control device that ensures the sending end electricity net safety stable is provided, to solve when the sending end grid disconnection, the power adjustment process of steam turbine slow, cause rotating speed too high, causes the turbine blade safety problem; The energy adjusting process of boiler slow, cause main vapour pressure too high, causes the emergency exit action, easily causes unit to cut the problems such as machine.
Technical solutions of the utility model:
A kind of fired power generating unit power prediction control device that ensures the sending end electricity net safety stable, it comprises:
The high frequency state of emergency and predicting unit, according to the input signal distinguishing electrical network whether in the high frequency state of emergency, when the high frequency state of emergency, the output fast power returns and falls signal, power control target, power of the assembling unit setting and power variation rate, with speed regulator PREDICTIVE CONTROL unit and boiler PREDICTIVE CONTROL unit, is electrically connected to;
Speed regulator PREDICTIVE CONTROL unit, under the high frequency state of emergency, the power setting of sending according to the high frequency state of emergency and predicting unit carries out the control of PID power, during overspeed protection OPC actuating signal is sent, the integration output state is readjusted to the power setting into prediction, at fast power, return and fall during signal sends, cancel or reduce the restriction of regulating command speed limit link, the high pressure valve instruction of output is sent to the server of speed adjusting gear, is electrically connected to the server of speed adjusting gear;
Boiler PREDICTIVE CONTROL unit, under the power grid high-frequency state of emergency, the fast power of sending according to the high frequency state of emergency and predicting unit returns and falls signal, automatically analog control system MCS control mode is converted to boiler follow BF mode, according to power variation rate connection, cuts coal pulverizer, accelerate the response of fuel supply process, return and fall signal while sending at fast power, electronic pressure relieving valve PCV is carried out to open and close controlling, according to power variation rate signal, bypass BP is controlled, be electrically connected to boiler and subsidiary engine;
The high frequency state of emergency and predicting unit comprise:
High frequency state of emergency discrimination module, carry out logical operation according to overspeed protection OPC actuating signal, tach signal and unit off-grid signal, judges that whether system is in the high frequency state of emergency, with state of emergency broadening module, is electrically connected to;
State of emergency broadening module, the high frequency state of emergency signal of sending into according to high frequency state of emergency discrimination module, carry out broadening by the time of setting, be output as fast and return and fall power signal, be electrically connected to power variation rate memory, power setting memory and supervisory control system;
Generator power, frequency and voltage acquisition module, gathered power, frequency and the voltage of generator end, with power, frequency and voltage factor correcting module, is electrically connected to;
Power, frequency and voltage factor correcting module, frequency and voltage factor correction generator power according to network load, the generator power of measuring while making the OPC action, on total amount with load balancing, output one tunnel of affiliated module is electrically connected to power variation rate memory after delayer, one tunnel directly is electrically connected to power variation rate memory, and a road is electrically connected to the power setting memory;
Power variation rate memory, be subject to return fast the rising edge that falls power signal FB and trigger, the ratio of generator power before generator power and off-the-line while calculating off-the-line, and write memory also keeps;
The power setting memory, in the moment of state of emergency broadening module output rising edge, will be somebody's turn to do the power of the assembling unit write memory of " promptly " moment measurement, keep during state of emergency broadening and set output as the power of the assembling unit, in the state of emergency, memory will keep always.
Speed regulator PREDICTIVE CONTROL unit comprises that integral element module and state of emergency speed limit that state can be reset exit module, and the integral element module that state can be reset exits module by the 3rd adder with state of emergency speed limit and is connected.
Boiler PREDICTIVE CONTROL unit comprises:
" power following " control mode modular converter: the control mode of falling signal, analog control system MCS of returning fast of sending according to the high frequency state of emergency and predicting unit is set to " boiler follow " mode, with the first routing switch, is electrically connected to;
" boiler follow " controller output tracking module, under other control mode, make " boiler follow " controller form a closed loop that stop-valve pressure is followed the tracks of, the correct output state that keeps PID, while avoiding being switched to " boiler follow " control mode under the high frequency state of emergency, the generation transition of output state, be electrically connected to the first adder-subtracter;
Coal pulverizer excision and fuel distribution module, according to the power variation rate, initial time in high frequency state of emergency amount, trigger and start coal pulverizer excision logic, excision is close to the corresponding coal pulverizer quantity of power variation rate, accelerate the control response speed of fuel, alleviate fuel and adjust the slow problem that main vapour pressure is high that causes.
The fired power generating unit power prediction control device of described guarantee sending end electricity net safety stable; it is the moment in overspeed protection (OPC) action, measures generator active power, active power or after corrected Calculation; control and set as the power of the assembling unit of prediction, the power of the assembling unit is controlled.
The fired power generating unit power prediction control device of described guarantee sending end electricity net safety stable; during overspeed protection (OPC) actuating signal is sent; the output state of integral element during the power P ID of speed regulator is controlled; be adjusted into the conversion numerical value that predicted power is set; the conversion numerical value of the power setting of described prediction is the generator active power of measuring at OPC action initial time; through revising and converting, be re-used as the displacement numerical value of the output state of integral element.
The utility model beneficial effect:
The utility model is after the sending end grid disconnection, lonely net trend can change immediately, in lonely net, the power of each power plant will be redistributed naturally, naturally the distribution power of utilization initial time under the high frequency state of emergency, after frequency and the correction of the voltage factor, as the power setting of prediction, this is the feature had of the present utility model.This feature has ensured that in electrical network, each power plant, to disperse independently control mode, when the sending end grid disconnection, coordinates reasonably to distribute the adjusting task, makes electrical network reach power-balance, has reduced the stable state frequency difference that classical control system exists; And ensured system of the present utility model and the stable machine control system of cutting, and can control independently without writing to each other, keep natively coordinating.
The utility model adopts Prediction and Control Technology, in the situation that sending end grid disconnection, lonely net load rejection and the load rejection of unit off-grid have realized five coordinations, has effectively improved sending end electrical network and unit safety stability, particularly:
Realized the coordination that Opc primary frequency modulation, power are controlled; In effective guarantee turbine blade safety, improve the stability of governing system and electrical network.
Realized coordinating between governing system and boiler control, be to coordinate between power and fuel vapor pressure-controlled, overcome the conflicts that produce because of the speed difference between steam turbine and boiler control, effectively prevented that the too high emergency exit that causes of vapour pressure from moving, and improved the unit safety reliability.
Realize the coordination between each Power Plant in lonely net, the power that the interior machine reasonable set of lonely net is shared after lonely net load rejection is adjusted task, unit is by setting and regulated separately, and the power that can not occur to cause because machine unit characteristic is different with parameter is grabbed and conflict, has avoided the vibration formed thus.
Realized that the power of the assembling unit is controlled and the lonely balance and coordination of loading of netting, the power setting summation that in lonely the net, unit is predicted is separately netted load with the orphan and is equated, after each self-regulation of unit, mains frequency can turn back to rated frequency.
Realized that unit controls the coordination of cutting the machine measure with electricity net safety stable, unit control cut the machine measure with electricity net safety stable can be without communicating to connect and cooperating, each self-adjusting and action, it is natural harmonious that both cooperation keeps.
The utility model is to take unit to be disperseed independent control as unit, between unit, unit links without communicating by letter with the stable machine of cutting, automatically mutually coordinates.This distributed coordination control technology, the sending end grid disconnection caused for unpredictable character fault, frequently stable for the lonely net height under hazardous condition, possess very strong adaptability,
The utility model can significantly improve sending end power grid high-frequency maintenance level, and under the electrical network robustness under raising Unpredictability fault and hazardous condition, the anti-disaster ability of electrical network, improve unit safety, has significant social benefit
The utility model is with control technology cheaply, effectively solve the frequency security stable problem of the little net of large machine, after eliminating these restraining factors, electrical network just can be by large-scale unit access 220kV regional power grid when planning, dissolve the load after by 500kV get in touch with the change send, eliminated the roundabout of load current, the electric energy loss of the power transmission network greatly reduced, be the energy-saving and emission-reduction measure that a kind of less investment, effect are large.
The utility model has solved large-scale unit access 220kV regional power grid key issue, after large-scale unit access 220kV regional power grid, dissolve 220kV regional power grid load of generated output, sending into the 500kV grid power reduces in a large number, the corresponding capacity that reduces the 500kV power transformating and supplying facility, can be corresponding the huge investment of saving 500kV electrical network primary equipment, there is significant economic benefit.
The utility model utilizes the natural partition characteristic of the power of the assembling unit after the sending end grid disconnection, do not need to build Centralized Control System, with decentralized control, controlled, there is the enforcement technology simple, characteristics with low cost, and, the utility model and domestic current relevant criterion, standard and regulation do not clash, be beneficial to and develop on prior art and transform, be beneficial to popularization, solved when the sending end grid disconnection, the power adjustment process of steam turbine slow, cause rotating speed too high, cause the turbine blade safety problem; The energy adjusting process of boiler slow, cause main vapour pressure too high, causes the emergency exit action, easily causes unit to cut the problems such as machine.
the accompanying drawing explanation:
Fig. 1 is each control unit composition frame chart of the utility model;
Fig. 2 is the utility model high frequency state of emergency and predicting unit modular structure schematic diagram;
Fig. 3 is the utility model speed regulator PREDICTIVE CONTROL unit module structural representation;
Fig. 4 is the utility model boiler PREDICTIVE CONTROL unit module structural representation;
Fig. 5 is the analogous diagram of conventional governing system when electrical network throws away 40% load;
Fig. 6 is the analogous diagram of the utility model control system when throwing away 40% unit output.
embodiment:
Principle and character that during the sending end grid disconnection, the lonely net power of the assembling unit is distributed:
When the sending end grid disconnection, lonely net trend changes immediately, unit generation power is redistributed, theoretical foundation of the present utility model, be based upon on the character of unit generation power division after lonely net off-the-line, due to the dynamo-electric process complexity of electrical network, its character of must deriving in the ideal situation, then analyze actual electric network and desirable departing from property of electrical network.
When the sending end grid disconnection, in lonely net, the electromagnetism synchronous torque of each generator is mutually led and is drawn, and each unit in electrical network can keep synchronous, rise of rotational speed speed is basically identical, the moment that arrives OPC action (3090rpm) is basic identical, therefore, can suppose that in lonely net, generating unit speed is consistent.After grid disconnection with OPC action before this period, because valve is servo, the time delay of pipeline and cylinder, can suppose that the mechanical output of prime mover is before the OPC action, power does not change; After the voltage of ignoring load and frequency effect, the character of unit power division in the time of can obtaining sending end grid disconnection under the supposition state.
Keep the principle of balance at synchronization according to electric network swim, after grid disconnection, unit is identical in the moment of OPC action, now inscribes all each the self-metering generated outputs of unit of lonely net, nets load with the orphan and equates, is called character 1.
Character 1 shows, all units in electrical network, and the unit generation power of measuring in the moment of OPC action, carry out each self-adjusting as the power setting of governing system, can make grid generation power equate with loading, and mains frequency can turn back to specified.
[0001] in lonely net, m platform generating set is arranged, according to electro-mechanical principle, can derive following standardization formula
<2>
Wherein,
it is the front generated output of i platform unit solution in lonely net
with power after off-the-line
poor,
for this unit generation capacity,
for this turbine generator inertia time constant.
the poor of lonely net load power after lonely net off-the-line front generating gross power and off-the-line.
<2>formula shows: after off-the-line, when OPC moves, measure the unit generated output and set as the power of the assembling unit of prediction
, when each unit is set adjusting by predicted power, the uneven gross power of lonely net
the adjustment task be by the pro rate of the product of each unit capacity and turbine generator inertia time constant to each unit in net, this character is called character 2.
Notice, the moment of inertia time constant difference of Large Hydropower Station and fired power generating unit is little, the uneven gross power of lonely net
basically be to each unit according to the pro rate of unit capacity size.By the character that after this grid disconnection, generated output distributes naturally, the unit original machine power being regulated, is fair and reasonable.
Load rejection power
, the moment of inertia time constant
, rotating speed
and raising speed
with OPC operate time
relational expression can derive as follows:
<3>
In formula, all variablees are perunit value
OPC in the operate time that rises to 3090rpm is:
The moment of inertia time constant of 300MW and above fired power generating unit is greater than 8.4 seconds, at unit generation power, all throws away in situation,
=1, can calculate OPC operate time is 0.27 second.
And be less than or equal to 0.2 second whole group of operate time of electricity net safety stable controlling system control of section, so be less than fired power generating unit OPC operate time whole group of operate time of electricity net safety stable controlling system.
If after off-the-line, safety stabilization control system is to owe the Qie Celveqie machine, stablely cut the lonely net power of the assembling unit after machine and again naturally distribute, after having assigned, OPC moves subsequently, the unit generation power that this measures constantly, still retention properties 1 and character 1.Therefore, no matter whether security stability control system cuts machine, and the generated output of measuring during the OPC action is as the power setting of speed regulator, and always correct, this character, be called character 1.
Above-mentioned character is derived according to supposition, and in actual electric network, situation can depart to some extent with above-mentioned character, and according to simulation calculation, the character of actual electric network is as follows:
Various fault disconnections are occurring in the lonely net that unit or single factory homotype unit form, and the power of the assembling unit can not fluctuate, and the power setting of prediction meets three character, and departure degree is very little.
The lonely net fault-free trip off-the-line that the dissimilar unit of many factories forms, power of the assembling unit fluctuation is minimum, and the power setting of prediction meets three character, and departure degree is very little.
Many factories form sending end electrical network generation three-phase ground, alternate, single-phase permanent fault and off-the-line, lonely net unit can fluctuate mutually, if lonely net load rejection rate (unbalance factor) is greater than 50%, under a few cases, the power setting of prediction departs from character 2, unit adjusting task maldistribution phenomenon appears, it is balance that but the power of the assembling unit is set with lonely net load, the degree that departs from character 1 is very little, control system can ensure that high frequency is stable, the distribution that just unit is regulated task is unjust phenomenon slightly, in service in actual electric network, this situation is very rare, electrical network has just been considered the power-balance problem when planning and operation, basically do not exist the load rejection rate to be greater than the lonely net of factory more than 50%.
Embodiment of the present utility model
It comprises (see figure 1) a kind of fired power generating unit power prediction control device that ensures the sending end electricity net safety stable:
The high frequency state of emergency and predicting unit 1, according to the input signal distinguishing electrical network whether in the high frequency state of emergency, when the high frequency state of emergency, the output fast power returns signal, power control target, power of the assembling unit setting and the power variation rate of falling, with speed regulator PREDICTIVE CONTROL unit 2, with boiler PREDICTIVE CONTROL unit 3 signals of telecommunication, be connected, the high frequency state of emergency and predicting unit 1 are connected and carry out information interaction with automatic power generation system (AGC) by supervisory control system.
The function of the high frequency state of emergency and predicting unit 1 is, dopes fast, accurately, reliably to net load with the orphan and keep the power of the assembling unit of balance to set, for the rapid adjustment of vapour pressure, fuel, air quantity provides PREDICTIVE CONTROL amount accurately.Whether it differentiates electrical network in the high frequency state of emergency according to the signal that comprises overspeed protection (OPC) actuating signal, and the state of emergency is carried out to time explanation, and the output fast power returns and falls signal; Utilization is distributing the power of the assembling unit naturally at off-the-line initial stage electrical network, in overspeed protection (OPC) action constantly, measure the power of the assembling unit of the power of the assembling unit after as grid disconnection, after the LOAD FREQUENCY factor and the correction of the voltage factor, as the power setting of predicting under the high frequency state of emergency, output to speed regulator PREDICTIVE CONTROL unit; The regulated quantitys such as rated output rate of change output boiler PREDICTIVE CONTROL unit.
The high frequency state of emergency and predicting unit comprise (see figure 2):
High frequency state of emergency discrimination module, carry out logical operation according to overspeed protection OPC actuating signal, tach signal and unit off-grid signal, judges that whether system is in the high frequency state of emergency, with state of emergency broadening module by signal, is connected; The basic handling logic is: the actuating signal of sending according to overspeed protection OPC, the out-of-limit signal of rotating speed (tach signal and rotary speed setting signal ω set
??
?output after comparison operation) and the logic NOT signal of unit off-grid carry out the logical AND operation, criterion as unit in the high frequency state, the out-of-limit signal of rotating speed plays and prevents misoperation use, the high frequency state of emergency is differentiated basic logic can determine two kinds of high frequency fault forms that may occur: a. sending end grid disconnection, among orphan's net of unit under the high frequency state; B. the orphan nets interior unit, the line tripping of loading greatly.This module only comprises basic logic, but the utility model is not limited to utilize other signals to carry out logical combination, as: consider that under the sliding pressure operation state, unit does not participate in the high frequency adjusting, the sliding pressure status signal can be got to this module of " non-" rear access.
State of emergency broadening module, the high frequency state of emergency signal of sending into according to high frequency state of emergency discrimination module, carry out broadening by the time of setting, be output as fast and return and fall power signal, with power variation rate memory, the power setting memory is connected with the supervisory control system wire, the high frequency state of emergency signal that it is sent into according to high frequency state of emergency discrimination module, carry out broadening by the time of setting, be output as fast and return and fall power signal FB(Fast Back), represent the emergency that pulls back to fast setting power of machine furnace control system, this be one with RB(Run Back) and FCB(Fast Cut Back) event signal of larger difference arranged.FB and RB difference be, it is not according to adjusting power or energy under given pace or time sequencing, but by the signal of prediction rapid adjustment unit output once; It and FCB difference be, FCB is the whole loads that throw away to mains supply, and FB is unit, is adjusted downward to fast the setting power of prediction to mains supply.The high frequency state of emergency (returning fast the process in the time broadening that falls power signal FB) refer to lonely net frequency from high frequency to stable state dynamic process, time broadening is set at 200 ~ 300s, for fired power generating unit, this period has comprised the rotating speed of steam turbine and the dynamic process that power is adjusted, and has comprised the critical adjustment process that fluctuates for the first time of boiler pressure;
Generator power, frequency and voltage acquisition module, power, frequency and voltage to generator end are gathered, with power, frequency and voltage factor correcting module signal, be connected, the generator power that the power of Generator end is sampled and obtained, take the delayer time delay mode of 5 ~ 10 seconds, obtain the power of the front generator of off-the-line;
Power, frequency and voltage factor correcting module, frequency and voltage factor correction generator power according to network load, the generator power of measuring while making the OPC action, on total amount with load balancing, output one tunnel of affiliated module after delayer, with power variation rate memory signals, be connected output off-the-line before power P
-N, power P when a road directly is connected the output off-the-line with power variation rate memory signals, power P (promptly) when road is connected the output off-the-line with the power setting memory signals;
Power variation rate memory, be subject to return fast the rising edge that falls power signal FB and trigger, generator power P before generator power P and off-the-line while calculating off-the-line
-Nratio, write memory also keeps;
The power setting memory, in the moment of state of emergency broadening module output rising edge, to be somebody's turn to do the power of the assembling unit P write memory that " promptly " state is measured constantly, keep during state of emergency broadening and set output as the power of the assembling unit, in the state of emergency, memory will keep always, it is in the moment of state of emergency broadening module output rising edge (being the OPC action moment), to be somebody's turn to do the power of the assembling unit write memory of " promptly " moment measurement, keep during state of emergency broadening and set output as the power of the assembling unit, if supervisory control system is not removed " promptly " state, memory will keep always.If " state of emergency " is removed in monitoring, memory will write the power of the assembling unit setting that supervisory control system is sent.It may be that automatic power generation system (AGC) is sent that power setting is sent in monitoring, has the power setting of " remote control " character, may be also that the operations staff of power plant operation writes, and has the power setting of " this locality " character.
Speed regulator PREDICTIVE CONTROL unit 2(is shown in Fig. 3):
Under the high frequency state of emergency, the power setting of sending according to the high frequency state of emergency and predicting unit 1 carries out the control of PID power, during overspeed protection OPC actuating signal is sent, the integration output state is readjusted to the power setting into prediction, return and fall during signal sends at fast power, cancel or reduce the restriction of regulating command speed limit link, the high pressure valve instruction of output is sent to the server of speed adjusting gear, be connected with the server wire of speed adjusting gear; Speed regulator PREDICTIVE CONTROL unit 2 comprises that integral element module 3.1 and state of emergency speed limit that state can be reset exit module 3.2, and the integral element module 3.1 that state can be reset exits module 3.2 by the 3rd adder 3.5 and state of emergency speed limit and is connected.
Under the normal state of electrical network, this unit carries out conventional PID to be regulated, and under the high frequency state of emergency after off-the-line, its power setting is switched to by the high frequency state of emergency and predicting unit 1 power setting of predicting after grid disconnection.During overspeed protection (OPC) actuating signal is sent; be that the high pressure valve control is transferred to OPC, speed regulator lose the high pressure valve control during, speed regulator utilizes this period to carry out the conversion of state; by the output state of integral element, be converted into the power setting of prediction.After overspeed protection (OPC) actuating signal finishes, when the high pressure valve control is transferred to speed regulator again, the integral element output state of speed regulator PID has been converted into the power setting of prediction.Return and fall during signal sends at fast power, the restriction of regulating command speed limit link will be cancelled or reduce in speed regulator PREDICTIVE CONTROL unit, to adapt to the significantly variation of correct regulating command.The effect of this unit is the conflict that solves overspeed protection (opc), the control of speed regulator power and primary frequency modulation; make between the three to keep coordinating; solve the instability problem of OPC perseveration unit and grid power oscillation on large scale; make the power of the assembling unit and mains frequency fast, steadily turn back to rated frequency, ensure unit and power grid security.This unit is comprised of primary frequency modulation, power P ID adjuster and speed limit amplitude limit link, in the digital electro-hydraulic governing system, in (DEH), build, with conventional speed regulator difference, be, the integral element module 3.1 that integral element in PID takes state to reset, state of emergency speed limit exits module 3.2.Particularly, the function declaration of each module is as follows:
The integral element module 3.1 that state can be reset is by state Resetting Switching 3.1.1, discharge switch 3.1.2, and integration state replacement coefficient 3.1.3, pure integral element 3.1.4 and corresponding control loop form.When OPC moves, state Resetting Switching 3.1.1 signal condition is " T ", export the power setting signal of " Y " sign to the 4th adder-subtracter 3.1.6, now power setting has been the predicted power of unit after grid disconnection, discharge switch 3.1.2 gets integral element module 3.1 output signals that state can be reset, and forms inner feedback loop.Due to integration state replacement coefficient, 3.1.3 is very large, and feedback loop can be adjusted to 3.2 output close to 0 in a step-length, and the predicted power into unit after grid disconnection is just clamped down in now pure integral element 3.1.4 output.When OPC exits, state is " F ", and discharge switch 3.1.2 cuts off feedback loop, and state Resetting Switching 3.1.1 is output as 0, and the output of the integral element 3.2 that state can be reset is exactly the output of pure integral element, i.e. the predicted power of unit after grid disconnection.
The 3rd adder-subtracter is got the output signal of integration state replacement coefficient 3.1.3 and the output signal of the second adder-subtracter 3.6 is delivered to the 3rd adder-subtracter 3.1.5, after being subtracted calculating, by integral constant and integration numerical value 1/S 3.1.4, undertaken delivering to the 4th adder-subtracter 3.1.6 after integral and calculating.Output signal to the 3rd adder 3.5 by the 4th adder-subtracter 3.1.6, rotating speed carries out plus and minus calculation through after primary frequency modulation, with power of the assembling unit P, together with power of the assembling unit setting, delivering to the second adder-subtracter 3.6, export to lead up to after proportionality constant amplifies and deliver to the 3rd adder 3.5, the 3rd adder 3.5 is delivered in one tunnel after derivative constant and derivative constant value S carry out differential calculation, the 3rd adder 3.5 is after adding computing, export speed limit module 3.2.1 to, with the Y end of Third Road by switch 3.2.2, speed limit module 3.2.1 exports the N end of Third Road by switch 3.2.2 to, Third Road falls signal FB triggering by switch 3.2.2 by returning fast, amplitude limit module 3.3 is delivered in output, the output of amplitude limit module 3.3 with deliver to the 4th adder together with output through after primary frequency modulation by forming valve instruction output after adding computing.
Boiler PREDICTIVE CONTROL unit 3(is shown in Fig. 4)
Under the power grid high-frequency state of emergency, the fast power of sending according to the high frequency state of emergency and predicting unit 1 returns and falls signal, automatically analog control system (MCS) control mode is converted to boiler follow (BF) mode, cut coal pulverizer according to power variation rate connection, accelerate the response of fuel supply process, return and fall signal while sending at fast power, electronic pressure relieving valve (PCV) is carried out to open and close controlling, according to power variation rate signal, bypass (BP) is controlled, be electrically connected to boiler and subsidiary engine;
Boiler PREDICTIVE CONTROL unit 3 comprises (see figure 4): " power following " control mode modular converter 4.1: the control mode of falling signal, analog control system (MCS) of returning fast of sending according to the high frequency state of emergency and predicting unit 1 is set to " boiler follow " mode;
" boiler follow " controller output tracking module 4.2, under other control mode, make " boiler follow " controller form a closed loop that stop-valve pressure is followed the tracks of, the correct output state that keeps PID, while avoiding being switched to " boiler follow " control mode under the high frequency state of emergency, the generation transition of output state; Coal pulverizer excision and fuel distribution module 4.3, according to the power variation rate, initial time in high frequency state of emergency amount, trigger and start coal pulverizer excision logic, according to owing to cut principle, excision, close to the corresponding coal pulverizer quantity of power variation rate, is accelerated the control response speed of fuel, alleviates fuel and adjusts the slow problem that main vapour pressure is high that causes.
The course of work: boiler PREDICTIVE CONTROL unit receives fast and returns and fall signal FB, spray water flux, the high pressure valve valve position signal, main vapour pressure is set TPs, the information such as power variation rate and main vapour pressure, spray water flux and high pressure valve valve position signal are delivered to two inputs of first adder 4.7, after adding computing, Output rusults is delivered to an input of second adder 4.8, main vapour pressure is set the input value of the output of TPs and secondary route switch as the first adder-subtracter, after subtracting computing, deliver to vapour pressure and fuel Control PID module 4.6, an input of second adder 4.8 is delivered in the output of vapour pressure and fuel Control PID module 4.6, second adder 4.8 output boiler follows are controlled output signal, deliver to the N input of secondary route switch and the Y input of the first routing switch 4.4, stop-valve pressure is connected to secondary route switch Y input, the output of second adder 4.8 is connected to the N input of secondary route switch, other control mode outputs of N input termination of the first routing switch 4.4, the output boiler follow of Y input termination second adder 4.8 is controlled output signal, the first routing switch 4.4 output boiler master order to fuel are controlled functional module 4.9, the coal pulverizer that outputs to that fuel is controlled functional module 4.9 excises and fuel distribution module 4.3, signal falls in coal pulverizer excision and the fuel distribution module 4.3 received power rate of change and quick returning, output coal pulverizer Resection in Treatment and fuel control command.
In the moment of overspeed protection (OPC) action, measure generator active power, active power or after corrected Calculation, control and set as the power of the assembling unit of prediction, and the power of the assembling unit is controlled.
During overspeed protection (OPC) actuating signal is sent; the output state of integral element during the power P ID of speed regulator is controlled; be adjusted into the conversion numerical value that predicted power is set; the conversion numerical value of the power setting of described prediction is the generator active power of measuring at OPC action initial time; through revising and converting, be re-used as the displacement numerical value of the output state of integral element.
Integration mode:
The utility model is in turbo generator set Distributed Control System DCS, the high frequency state of emergency and predicting unit 1 and speed regulator PREDICTIVE CONTROL unit 2 are embedded into to the digital electro-hydraulic control system (DEH) in DCS, boiler PREDICTIVE CONTROL unit 3 is embedded in analog control system (MCS).
The high frequency state of emergency and predicting unit, exploitation becomes numerical control in DEH and shields new hardware module in cabinet, and its processing speed is identical with the overspeed protection module in DEH.
Speed regulator PREDICTIVE CONTROL unit, exploitation becomes new module and replaces the speed regulating control module in former DEH, or the software of master mould member is changed.
The development scheme of boiler PREDICTIVE CONTROL unit, by DCS signal and functional configuration mode, " power following " control mode modular converter in Fig. 4 4.1 and " boiler follow " controller output tracking module 4.2 are embedded in " boiler follow " mode control loop of MCS boiler master part; Fuel in fuel sub-system distributes control section, according to returning fast signal FB and the power variation rate of falling, implements prediction excision coal pulverizer function 4.3.
Data acquisition and communication mode, the power signal, tach signal and the OPC actuating signal that are input to the high frequency state of emergency and predicting unit should employing directly be adopted mode and special optic fibre communication mode, ensure described signals collecting and the rapidity of communicating by letter and synchronism.All the other I/O signals are gathered and are transmitted by data acquisition and the communication network of DCS.
Fig. 5 and Fig. 6 are: Qi Zhong ⊿ ω-speed discrepancy (Hz) of conventional governing system and the simulation comparison of the utility model control system when throwing away 40% unit output, Pe-generated output (pu), Pm-mechanical output (pu),
OPC-OPC actuating signal (1 is action, and 0 for being failure to actuate).
Put down in writing embodiment in this specification, but the utility model is not limited to the details that above-mentioned demonstration is implemented, in the situation that do not break away from spirit of the present utility model and essential characteristic also available additive method realize the utility model, therefore, should regard embodiment as exemplary, and it is nonrestrictive, scope of the present utility model is limited by claims rather than above-mentioned explanation, therefore be intended to the implication that is equal to important document and all changes in scope that drop on claim are included in the utility model, the any Reference numeral in claim should be considered as limit related claim.In addition, obviously other unit or module do not got rid of in " comprising " word, all is subject to the protection of this patent yet.Parameter values described in embodiment is only example, parameter values should be considered as limit related claim.A plurality of unit of stating in claim, module also can or be installed and realize by software or hardware by a unit or module.A unit of stating in claim, module also can or be installed and realize by software or hardware by a plurality of unit or module.
Claims (3)
1. ensure the fired power generating unit power prediction control device of sending end electricity net safety stable, it is characterized in that: it comprises the high frequency state of emergency and predicting unit (1), and the high frequency state of emergency and predicting unit (1) are electrically connected to speed regulator PREDICTIVE CONTROL unit (2) and boiler PREDICTIVE CONTROL unit (3); Speed regulator PREDICTIVE CONTROL unit (2) is electrically connected to the server of speed adjusting gear, and boiler PREDICTIVE CONTROL unit (3) is electrically connected to boiler and subsidiary engine.
2. the fired power generating unit power prediction control device of guarantee sending end electricity net safety stable according to claim 1, it is characterized in that: the high frequency state of emergency and predicting unit (1) comprising: high frequency state of emergency discrimination module is electrically connected to state of emergency broadening module; State of emergency broadening module is electrically connected to power variation rate memory, power setting memory and supervisory control system; Generator power, frequency are electrically connected to power, frequency and voltage factor correcting module with voltage acquisition module; Output one tunnel of power, frequency and voltage factor correcting module is electrically connected to power variation rate memory after delayer, and a road directly is electrically connected to power variation rate memory, and a road is electrically connected to the power setting memory.
3. the fired power generating unit power prediction control device of guarantee sending end electricity net safety stable according to claim 1, it is characterized in that: speed regulator PREDICTIVE CONTROL unit (2) comprises that integral element module (3.1) and state of emergency speed limit that state can be reset exit module (3.2), and the integral element module (3.1) that state can be reset exits module (3.2) by the 3rd adder (3.5) and state of emergency speed limit and is connected.
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| CN 201220676564 CN203086401U (en) | 2012-12-10 | 2012-12-10 | Thermal power generating unit power prediction control device capable of guaranteeing safety and stability of export electric network |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103501145A (en) * | 2013-09-16 | 2014-01-08 | 贵州电网公司电网规划研究中心 | Power grid high frequency stability prediction control method based on isolated network tide transfer principle |
| CN104184169A (en) * | 2014-09-11 | 2014-12-03 | 国家电网公司 | Transient generator tripping control method considering wind power integration and wind-thermal coordination |
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2012
- 2012-12-10 CN CN 201220676564 patent/CN203086401U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103501145A (en) * | 2013-09-16 | 2014-01-08 | 贵州电网公司电网规划研究中心 | Power grid high frequency stability prediction control method based on isolated network tide transfer principle |
| CN103501145B (en) * | 2013-09-16 | 2016-05-11 | 贵州电网公司电网规划研究中心 | Power grid high-frequency stability forecast control method based on lonely net trend principle of transfer |
| CN104184169A (en) * | 2014-09-11 | 2014-12-03 | 国家电网公司 | Transient generator tripping control method considering wind power integration and wind-thermal coordination |
| CN104184169B (en) * | 2014-09-11 | 2017-03-29 | 国家电网公司 | The transient state that a kind of meter and wind-electricity integration wind-fire are coordinated cuts machine control method |
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