CN103501145B - Power grid high-frequency stability forecast control method based on lonely net trend principle of transfer - Google Patents
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Abstract
The invention discloses the power grid high-frequency stability forecast control method based on lonely net trend principle of transfer, the trend principle of transfer of its electrical network during according to sending end off-the-line or lonely net load tripping operation, utilize trend to be transferred to the balance and coordination that generator distributes power, prediction power of the assembling unit control target is also controlled fast and accurately to units, comprises the steps: to gather generator power, generating unit speed, mains frequency and overspeed protection actuating signal; Form power grid high-frequency state of emergency signal through compound logic computing; This high frequency status signal is carried out to broadening; During broadening, gathering generator power deposits memory in and remains unchanged; Calculate power of the assembling unit control target according to memory power; During broadening, according to power control target, unit is carried out to power prediction control. The present invention can significantly improve the high frequency maintenance level of electrical network and the security of unit, has both good decentralized coordinating, universality, reliability and compatibility, has good economic results in society.
Description
Technical field:
The present invention relates to Power system security control field and Turbo-generator Set heating power control field,Relate in particular to a kind of power grid high-frequency stability forecast controlling party based on lonely net trend principle of transferMethod.
Background technology:
Be born to so far from power system, frequency promptly regulates task by set speed adjustment system oneInferior frequency modulation is born, and flies pendulum develop into digital electro-hydraulic control system now from the Edison at initial stage(DEH), although there is great variety in technology, on the control principle of primary frequency modulationNever there is change. Primary frequency modulation in principle according to frequency shift (FS) to the power of the assembling unitDeviation Control, is actually at electric network state and undergos mutation, and power of the assembling unit control target is not clearThe really regulative mode of a kind of "crossing river by touching stones" in situation, due to rotating speed and frequency byElectrical network electromechanical transient process produces, the comprised electromechanics of primary frequency modulation to original machine power adjustmentTransient process, is shown in Fig. 1, and therefore regulating the speed of turbine can not be faster than the process of electromechanical transient.This is that once frequency modulation performance is bad in the large disturbance situation of off-the-line, turbine rotating speed and mains frequencyThe basic reason of ascending to heaven. In the time of sending end grid disconnection, if generating and load power imbalanceDegree is larger, and speed fling lifting is easy to higher than 110%, with regard to the peace of entail dangers to turbine bladeEntirely, cause turbine emergency interrupting system to be shut down, thereby have a strong impact on the stabilization of power grids.
For preventing that speed fling lifting is higher than 110%, in the time that rotating speed is greater than 103%, steam turbine generatorGroup overspeed protection (OPC) can be moved, and steam off valve fast reducing unit output, canSo that mains frequency fast return is to normal, to ensure Turbine Safety. But work as OPCWhen release, the control of valve rotates back into again primary frequency modulation and the power control of speed regulator,Speed regulator has now lost correct power control and has set, still remain on before off-the-line,Exceed to a great extent the power setting of lonely net load level, make unit start again to increasePower, electrical network turns back to high frequency state once more, thereby causes that OPC moves again. ThisProcess circulates repeatedly, causes mains frequency and the power of the assembling unit to be the large amplitude wave of periodic zigzagMoving, finally cause lonely net large area dead electricity. This situation, at home sending end grid disconnection thingTherefore in repeatedly occur.
Equally, the boiler master of fired power generating unit is Deviation Control mode, large disturbance in the time of off-the-lineIn situation, boiler oil and vapour pressure adjustment process are difficult to catch up with steam turbine power adjustment process,Easily in removal of load process, form vapour pressure and ascend to heaven, cause safety door action accident.
The present patent application people's research is found, at current standard, code and regulatory documentsUnder the technical conditions of defined, the high frequency stability margin of fired power generating unit governing system is very low, separatesIf when when row, fired power generating unit power overloads 9% (unbalanced power supply rate) of power,Lonely net frequency just can not be stablized. Especially the sending end electrical network that the little net of large machine forms, power grid securityIn the situation that stabilizing control system and high-frequency cutting machine automatics can not play a role, high frequency is steadySurely be difficult to ensure, had a strong impact on the safety and stability reliability service of sending end electrical network and unit.
While solving sending end grid disconnection, the key of high frequency stable problem is, Accurate Prediction goes out orphanThe power of unit under net mode, accelerates original machine power adjustment process, enable to catch up with orExceed the electromechanical transient process of power system, effectively controlled frequency is ascended to heaven, and prevents that OPC from shakingSwing; Accelerate boiler oil and vapour pressure adjustment process, enable to catch up with load dumpPower adjustment process, ensures that vapour pressure is stable, prevents safety door action.
Summary of the invention:
The technical problem to be solved in the present invention: provide a kind of based on lonely net trend principle of transferPower grid high-frequency stability forecast control method, adopts primary frequency modulation technology to solve prior art,Exist in the time of sending end grid disconnection, generating set and load power imbalance degree is largerTime, prime mover control response speed is slow, and prime mover adjustment does not catch up with the change procedure of electrical network,Form serious speed fling lifting, rotating speed, easily higher than 110%, jeopardizes the peace of turbine bladeEntirely, cause turbine emergency interrupting system to be shut down, thereby have a strong impact on the stabilization of power grids and thermoelectricityUnit is in the time of off-the-line in large disturbance situation, and boiler oil and vapour pressure adjustment process are difficult to catch up with vapourWheel acc power adjustment process easily forms vapour pressure and ascends to heaven in removal of load process, causes safetyThe problems such as door action accident.
The present invention utilizes electric network swim to shift electromagnetic transient orphan is netted to interior each unitBalance, the coordination that generator power distributes and the irrelevant characteristic of moving with stability control equipment,Under the high frequency state of emergency, gather generator power, it calculation correction is become to speed regulator powerControl target, and implement immediately prediction (super relaxation) by power control target and control this baseIn the power grid high-frequency stability forecast control method of lonely net trend principle of transfer, there is good heightFrequently stablize control performance, and can produce significant safety economy benefit;
Technical solution of the present invention:
A power grid high-frequency stability forecast control method based on lonely net trend principle of transfer, itsBe characterised in that: it comprises the steps:
Step 1, collection unit generator power, generating unit speed, mains frequency and overspeed protection are movingMake signal;
Step 2, by the unit generation acc power described in step 1, generating unit speed, mains frequency andOverspeed protection actuating signal generates power grid high-frequency state of emergency judgement letter through compound logic computingNumber; Described compound logic computing is the combination of logical AND, logic OR and logic NOT;
Step 3, according to the judged result of the compound logic computing of step 2, when electrical network judge inWhen the high frequency state of emergency, power grid high-frequency state of emergency signal is carried out to broadening;
Step 4, in the time that high frequency state of emergency signal sends, by the generator power of this moment unit P0Deposit memory in, during power grid high-frequency state of emergency signal broadening, remain unchanged;
Step 5, according to the generator power P in step 4 memory0Calculate power of the assembling unit control orderMark Pobj,
Step 6, during high frequency state of emergency signal broadening, the power prediction control system of unitAccording to power control target P, obj controls the power of the assembling unit.
The high frequency state of emergency described in step 2 judges signal, be by the out-of-limit signal of rotating speed,The out-of-limit signal of mains frequency, overspeed protection OPC actuating signal and unit generation acc power becomePart signal or the whole signal changed in the out-of-limit signal of per unit value carry out compound logic computing, instituteThe compound logic computing of stating is the combination of logical AND, logic OR and logic NOT;
The out-of-limit signal of generating unit speed: rotating speed is more than or equal to setting value;
The out-of-limit signal of-mains frequency: mains frequency is more than or equal to setting value;
-overspeed protection (OPC) actuating signal: fired power generating unit collection, Hydropower Unit does not makeUse this signal;
-unit generation acc power changes the out-of-limit signal of perunit value: described unit generation acc powerChanging perunit value Δ P isP current time power P, P-ΔtWhen currentQuarter, the power ， ⊿ t of Qian ⊿ t was 5～10 seconds, and Pe is generator rating power, instituteStating the out-of-limit signal of unit generation acc power variation perunit value is that Δ P is greater than upper limit set valueOr be less than lower limit set value.
The computing formula of power of the assembling unit control target P obj described in step 5 is:
P0For the unit generation acc power that memory described in step 3 deposits in, k is loadCharacteristic correction coefficient,
U is the per unit value of voltage while measuring after off-the-line, U0For the voltage mark under stable stateValue, dfFor the meritorious frequency influence factor, f is frequency per unit value, and a, b, c are permanentThe proportionality coefficient of impedance, constant current, permanent power section, has a+b+c=1.
Unit control system described in step 6 is Control System for Thermal Power Units, utilizes meritRate control target P obj, by the governing system of fired power generating unit, fuel dispensing system, electromagnetismValve control and Bypass Control System, control fast.
Unit control system described in step 6 is Hydropower Unit, utilizes power control orderMark Pobj, controls fast by turbine governor system, to permit in servo-drive systemThe maximum closing velocity guide vane closing of being permitted, regulates Hydropower Unit power.
Beneficial effect of the present invention:
The present invention discloses, unit generator power P when lonely net trend shiftseThere is following principleAnd character:
Character 1: machine net balancing the load
In lonely net, each unit unit generation acc power sum equates with lonely net load.
Character 2: between unit, power division is coordinated rationally
The adjustment task of lonely net imbalance power is by each unit capacity and turbine generator inertiaThe ratio of the product of time constant is automatically assigned to each unit in net. Substantially be according toThe pro rate pondage of unit capacity size.
Character 3: prediction correctness and the stable machine system acting of cutting have nothing to do
Can prove, OPC moves the moment, rotating speed or mains frequency reach 103% timeCarve, to set generator power PeGather, be now engraved in stable while cutting the action of whole group of machineBetween after. After cutting machine will there is trend transfer in lonely net again, and moment enters generator power againRow redistributing again, whether no matter safety and stability section is cut machine control system is cut machine, isNo tripping or malfunction, the power of prediction is retention properties 1 and character 2 still
According to lonely net trend principle of transfer, control system forms and sees Fig. 2, is divided into lonely net trend and turnsMove and two parts of power grid high-frequency stability forecast control based on lonely net trend principle of transfer.
Lonely net self is as a kind of natural central control system, sending end grid disconnection or orphanAt the initial stage of load tripping operation when network operation, lonely net flow state shifts automatically divides fast to unitJoined machine net power-balance, coordinate between unit power signal.
Power grid high-frequency stability forecast control based on lonely net trend principle of transfer be the present inventionDescribed step, differentiates the high frequency state of emergency, measures the distribution of electric network swim state transitions unitThe power of giving unit, has obtained the power control target P under final stable stateobj. At electricityFrequently fault initial of net height, just know what has occurred electrical network, and what unit should do,Should be adjusted to how many, according to PobjNumerical value, immediately implement fast, accurately, oneThe control that step puts in place, implements fast transfer control to machine unit speed regulating device state, and unit is followedThe mutation process that upper lonely net trend shifts, the machine net of allowing reaches rapidly stable state.
The present invention has following control performance
1, significantly improve sending end power grid high-frequency maintenance level
Power grid high-frequency stability margin can be brought up to 50% from current 9%.
2, rapidity and the accuracy controlled
Because unit control system has just obtained power target accurately at the off-the-line initial stage, canCalculate immediately the controlled quentity controlled variable of maintenance machine net power-balance and machine capacity of furnace balance, to unit meritRate, fuel and vapour pressure are carried out instantaneous and PREDICTIVE CONTROL accurately. Original machine power is regulatedCaught up with electromechanical transient process, boiler oil and Steam Pressure Control of Circulated have been caught up with steam turbine power adjustingProcess, machine net, machine stove reach rapidly the balance of power and energy.
3, disperse independence
Each unit control in lonely net, overspeed protection (OPC), electrical network is stable cuts machine controlBetween, do not need communication connection to work in coordination with, take to disperse and control mode independently, canThe coordination forming natively.
4, harmony
1. steam turbine OPC and the collaborative and self-discipline of predicting speed regulator
During after off-the-line, removal of load regulates, OPC takes the lead in moving, in the mode of Fast ValvingReduce power, make mains frequency fast-descending, when OPC returns, pitch control is turnedDuring to predicted power speed regulator, control target and the output state of predicted power speed regulator are pressedUnit trend transfer signal has carried out accurate replacement, under network load poised state, carries outContinuous control, has avoided the rising again of frequency, has also just thoroughly eliminated OPC againAction.
Mutually collaborative between OPC and speed regulator, learn from other's strong points to offset one's weaknesses, make steam turbine power adjustmentProcess has been caught up with the electrical network electromechanical transient process after off-the-line, has avoided OPC vibration, avoidsThe low frequency load shedding that causes of the overshoot of power and frequency.
Emulation shows: OPC vibration does not occur in novel control, and removal of load rate is no more than 80%Time, OPC action frequency only has 1 time.
2. working in coordination with between the control of machine stove
By above-mentioned automatic measure, realize working in coordination with between the control of machine stove, make boiler oilCatch up with steam turbine power variation with Steam Pressure Control of Circulated. Emulation shows: unit is in removal of load 50%Time, can ensure that vapour pressure is stable, and safety door action accident does not occur.
3. the collaborative and self-discipline of controlling between unit
After off-the-line, the unit independent prediction of disperseing in lonely net power control target, and eachCarry out rapid adjustment from the power target by oneself prediction, because orphan nets the power order of interior unitMark sum equates with load, disperses to be independently actually and carries out accurately mutual working in coordination with, fastMachine net power is adjusted to balance by speed ground, and this cooperative mode does not interfere with each other, and do not exist mutuallyBetween power grab conflict.
4. stable section is cut the cooperative compensating of machine system and unit PREDICTIVE CONTROL
Before the action that stable section is cut machine system occurs in prediction signal collection, according to off-the-lineThe character 3 that trend circulation moves the power signal of distribution, unit control and electricity net safety stable are cutMachine measure can be without communication connection and cooperation, each self-adjusting and action, and both cooperations are protectedThat holds is harmonious. As action before and after stable control and unit PREDICTIVE CONTROL, it is a kind of phaseCollaborative mutually. The off-the-line outside stable control range as stable tripping or electrical network, the pre-observing and controlling of unitSystem shows standby and supplementary function.
5. universality and reliability
The system architecture of the unit high frequency Prediction and Control Technology based on trend principle of transfer is handleLonely net itself is as a natural centralized control system, and it stablizes the initial of accident at high frequencyMoment, for each unit assigned with balancing the load and distributed reasonable power command. This dayRight centralized control system has following characteristic:
1. universality: it does not exist the restriction of control range, no matter load line when lonely network operationRoad tripping operation or sending end grid disconnection, no matter where splitting point occurs in electrical network, also no matter lonelyNet size, lonely this natural centralized control system of net all can correctly be given an order. This generalAdaptive, is adapted to be difficult under disastrous condition the accident of prediction especially.
2. reliability: lonely this natural centralized control system of net malfunction can not occur and refusesMoving, there is not equipment fault and maintenance issues yet, completely reliable.
The program of Predictive Control System takes to embed design, does not increase hardware device, canSo that PREDICTIVE CONTROL program is embedded among operating software module, meet one-time authentication, exempt from all the lifeThe reliability requirement of safeguarding, is adapted to the splitting accident that probability is little, have a big risk. Meet and combat a natural disasterThe reliability requirement of mitigation facility.
Downward compatibility
Under other states during except the high frequency state of emergency, with the control knot of existing control systemStructure, parameter and characteristic are identical, do not increase new controller parameter, not with existing standard,There is any conflict in code and regulation, is beneficial to and applies.
Effect of the present invention and benefit:
Great safety benefit: significantly improve the security of sending end power grid high-frequency stability and unit,Significantly improve the anti-disaster ability of electrical network under Unpredictability fault, especially for urgently to be resolved hurrilyThe high frequency of regional power grid " large the little net of machine " stablize a difficult problem, have important using value.Significant green economy benefit: support large capacity unit to be linked in 220kV regional power grid,The load of directly dissolving, eliminates load bypass, reduces network loss; Dissolve after load, reduced500kV power transmission and transformation capacity, reduces 500kV contact parameter amount, saves investment.The important technology of intelligent grid supports: the present invention transforms the high frequency stable problem of sending end electrical networkFor ensure the advantage of power grid securities at different levels with superior Power Supplies Condition, build by Electric Power Network Planning,Form self-holding, the interregional contact of regional power grid life and support, transmission of electricity and contact function are clearly demarcated" earthwormization " electrical network, intelligent, efficient, the reliable green electrical network of final realization.
Utilization the invention solves prior art and adopts primary frequency modulation technology, existence in sending endWhen grid disconnection, when the uneven degree of generating set and load power is larger, prime mover controlResponse speed is slow, and prime mover adjustment does not catch up with the change procedure of electrical network, forms serious rotating speedAscend to heaven, rotating speed, easily higher than 110%, jeopardizes the safety of turbine blade, causes steam turbineEmergency trip system-down, thus have a strong impact on the stabilization of power grids and fired power generating unit is large in the time of off-the-lineIn disturbance situation, boiler oil and vapour pressure adjustment process are difficult to catch up with steam turbine power and adjustedJourney easily forms vapour pressure and ascends to heaven in removal of load process, and initiation safety door action accident etc. is askedTopic.
Brief description of the drawings
Fig. 1 is traditional primary frequency modulation controlling unit schematic diagram;
Fig. 2 is that system of the present invention forms schematic diagram;
Fig. 3 is that the present invention is in steam turbine signals collecting, power target prediction and PREDICTIVE CONTROL signalFigure;
Fig. 4 is the vapour that adopts 600MW supercritical turbine generator group of the present invention removal of load 50%Turbine process simulation figure, the Pm in figure is prime mover mechanical output, Pe is generator power;
Fig. 5 is the boiler mistake of 600MW supercritical turbine generator group of the present invention removal of load 50%Journey analogous diagram;
Fig. 6 is the loose PREDICTIVE CONTROL schematic diagram of hydraulic turbine component of the present invention;
When Fig. 7 is 700MW Load Rejection of Hydraulic Turbine 30%, the conventional primary frequency modulation emulation of water wheels unit is shownIntention;
Fig. 8 adopts speed timing simulation schematic diagram of the present invention while being 700MW Load Rejection of Hydraulic Turbine 30%;
Fig. 9 is that cut machine and regulates concentrated Optimal Control System schematic diagram hydroelectric power plant.
Figure 10 is forecast Control Algorithm and the block diagram based on lonely net trend principle of transfer.
Detailed description of the invention:
Control method of the present invention and step
A power grid high-frequency stability forecast control method based on lonely net trend principle of transfer, it comprisesFollowing step:
Step 1, collection unit generator power, generating unit speed, mains frequency and overspeed protection are movingMake signal;
Step 2, by the unit generation acc power described in step 1, generating unit speed, mains frequency andOverspeed protection actuating signal generates power grid high-frequency state of emergency judgement letter through compound logic computingNumber; Described compound logic computing is the combination of logical AND, logic OR and logic NOT;
Step 3, according to the judged result of the compound logic computing of step 2, when electrical network judge inWhen the high frequency state of emergency, power grid high-frequency state of emergency signal is carried out to broadening;
Step 4, in the time that high frequency state of emergency signal sends, by the generator power of this moment unit P0Deposit memory in, during power grid high-frequency state of emergency signal broadening, remain unchanged;
Step 5, according to the generator power P in step 4 memory0Calculate power of the assembling unit control orderMark Pobj,
Step 6, during high frequency state of emergency signal broadening, the power prediction control system of unitAccording to power control target P, obj controls the power of the assembling unit.
Forecast Control Algorithm and step based on lonely net trend principle of transfer are shown in Figure 10.
The high frequency state of emergency described in step 2 judges signal, by the out-of-limit signal of rotating speed, electricityNet frequency out-of-limit signal, overspeed protection OPC actuating signal and unit generation acc power changePart signal in the out-of-limit signal of per unit value or all signal carry out compound logic computing, described inCompound logic computing is the combination of logical AND, logic OR and logic NOT.
If mains frequency and generating unit speed are out-of-limit, both one of meet or exceed 1.03 (pu)Time, electrical network is in the high frequency state of emergency, or sending end grid disconnection has occurred, or lonely net occursLoad tripping operation. In order to judge reliably the power grid high-frequency state of emergency, take multiple differencesThe compound logic computing of the signal in source judges, mistake occurs when preventing certain abnormal signalJudgement. Gather unit generator power, generating unit speed, mains frequency and fired power generating unit superSpeed protection (OPC) operating state, forms following judgment signal:
The out-of-limit signal of-generating unit speed: rotating speed is more than or equal to setting value;
The out-of-limit signal of-mains frequency: mains frequency is more than or equal to setting value;
-overspeed protection (OPC) actuating signal: fired power generating unit overspeed protection (OPC) existsWhen rotating speed meets or exceeds 1.03 (pu) by instantaneous this signal that sends;
-unit generation acc power changes the out-of-limit signal of perunit value: described unit generation acc powerChanging perunit value Δ P isP current time power P, P-ΔtWhen currentQuarter, the power ， ⊿ t of Qian ⊿ t was 5～10 seconds, and Pe is generator rating power, instituteStating the out-of-limit signal of unit generation acc power variation perunit value is that Δ P is greater than upper limit set valueOr be less than lower limit set value.
The effect of step 3 is whole group of actions determining that the high frequency state of emergency and unit are dynamically adjustedTime, is determining after the power grid high-frequency state of emergency, by the exhibition of power grid high-frequency state of emergency signalWide, the time of broadening is exactly the time that high frequency emergency adjustment process experiences, and power grid high-frequency is steadyFixed emergent control process approximately 3 minutes.
The moment of step 4 after grid disconnection, experience an electromagnetic transient fastAfter, in lonely net, trend has just occurred to shift and change, and in lonely net, generator has also been redistributedPower, the initial time sending at power grid high-frequency state of emergency signal, i.e. generating unit speed or electricityWhen net frequency is specified 103%, and only carve at this moment, by set generator power P0, depositEnter memory, during power grid high-frequency state of emergency signal broadening, remain unchanged. Step 4Effect is to guarantee that the power of the assembling unit gathering has power between machine net balancing the load character, unitDistribute coordinate reasonable character and with the stable irrelevant character of machine system acting of cutting.
The effect of step 5 is the voltage of elimination load and the mistake that the frequency influence factor causesPoor. The computing formula of power of the assembling unit control target P obj described in step 5 is:
P0For the unit generation acc power that memory described in step 3 deposits in, k is loadCharacteristic correction coefficient,
U is the per unit value of voltage while measuring after off-the-line, U0For the voltage mark under stable stateValue, dfFor the meritorious frequency influence factor, f is frequency per unit value, and a, b, c are permanentThe proportionality coefficient of impedance, constant current, permanent power section, has a+b+c=1.
Unit control system described in step 6 is Control System for Thermal Power Units, utilizes meritRate control target P obj, by the governing system of fired power generating unit, fuel dispensing system, electromagnetismValve control and Bypass Control System, carry out fast, accurately, the prediction that settles at one go(super relaxation) controlled.
Unit control system described in step 6 is Hydropower Unit, utilizes power controlTarget P obj, controls fast and accurately by turbine governor system, to watchThe rapid guide vane closing of maximum closing velocity that dress system allows, regulates Hydropower Unit power.
The present invention is at fired power generating unit embodiment
1, trend shifts the Forecasting Methodology of distributing power signal
Fired power generating unit is overspeed protection meeting snap action in the time that rotating speed reaches 103%, tach signalGet OPC actuating signal, mains frequency signal is taken from power plant's high voltage bus voltage signal. ?These two signals of digital electro-hydraulic adjuster (DEH) all possess, by two separate sourcesWhether the logical AND of signal, can reliably differentiate this unit place electrical network in the urgent shape of high frequencyState, referring to Fig. 3.
2, steam turbine predicted power speed regulating control
Steam turbine predicted power speed regulating control is that the state based on predicted power signal can be resetPID speed regulator. It is with the power reset speed regulator power control loop joint PID it is predictedState, realized super relaxation the fast and accurately of mechanical output to steam turbine and controlled, makeThe control and regulation speed of steam turbine process, caught up with after grid disconnection dynamo-electric mistake fastJourney, has stablized mains frequency effectively, and mains frequency can not raise again, fundamentally keeps awayExempt from the vibration of OPC.
3 coal pulverizers promptly excise PREDICTIVE CONTROL
The generator power obtaining according to prediction is taked instantaneous in boiler oil distribution is controlledConnect and cut the coal pulverizer of correlated measure, make to realize quickly between fuel and vapour pressure balance.
4 magnetic valves (PCV) self-locking quick is opened control
In the time of the high frequency state of emergency, in not yet rising, carves pressure, and the instantaneous PCV of opening carriesFront release of pressure, pressure returns when specified and closes, and after one-off, with regard to locking, prevents PCV'sOpen and close vibration. The vapour pressure that effectively reduces off-the-line initial time is ascended to heaven, and ensures follow-up phase simultaneouslyVapour pressure steady.
Control is opened in 5 bypasses that start based on prediction soon
As the measure under degree of depth removal of load of Subcritical Units, in the high frequency state of emergencyTime, according to the order of severity of load rejection and steam pressure present situation, determine whether throw immediatelyEnter bypass, take to open soon and regulate continuously hybrid mode to surpass the control that relaxes. This measure can haveEffect reduces the vapour pressure of off-the-line initial time ascends to heaven, and ensures that the vapour pressure of follow-up phase is steady simultaneously.
Above-mentioned coal pulverizer promptly excises the mode that PREDICTIVE CONTROL is a kind of " taking away the firewood under the cauldron "; ElectricityMagnet valve (PCV) self-locking quick is opened and is controlled and belong to based on predicting that the bypass starting opens to control soonThe mode of " ineffectual remedy ", it cooperates mutually, can suppress furnace wall, pipeline and subcriticalThe heat accumulation of unit drum in degree of depth removal of load situation, has ensured pot in the time of sending end grid disconnectionStablizing of stove and steam turbine energy balance and vapour pressure, guarantees in removal of load 50% situation, superThere is not safety door action accident in the critical and critical unit of pressure.
4, the simulated effect after fired power generating unit enforcement
600MW supercritical turbine generator group is implemented, after the technical measures of this patent, to get rid of negativeWhen lotus 50%, the process simulation of main operating mode is shown in Fig. 4 and Fig. 5, and frequency and vapour pressure have all obtainedWell control, OPC concussion does not occur, safety door action does not occur.
The present invention is at the embodiment of hydroelectric power plant and water wheels unit:
1. hydraulic turbine power prediction speed regulating control embodiment
If the ratio of area power grid water power capacity is less, can take hydraulic turbine power predictionSpeed regulating control, the unit being dispersed in lonely net carries out PREDICTIVE CONTROL independently, and control system is shown inFig. 6.
In the time of the high frequency state of emergency, hydraulic turbine power prediction speed regulating control takes predicted power to existThe technical measures such as the preposition and PID state replacement of PID, the stator allowing with servo control mechanism is the fastestClosing velocity, in hydraulic turbine hydraulic pressure is adjusted the scope of protecting regulation, promptly regulates, and suppresses to turnSpeed is ascended to heaven, and effectively reduces the overshoot that few servo-drive system integration causes, and prevents that electrical network from occurring lowFrequently cutting load.
Unit unit possesses the signal using to some extent, and system is completely independent, does not need and unitOutside, unit connects, and reliability is high.
Adopt hydraulic turbine power prediction speed regulating control of the present invention, considering that maximum (top) speed is not superCross under 110% restrictive condition, water wheels unit can be by removal of load rate from 10% of primary frequency modulation,Bring up to 30%. Primary frequency modulation when Fig. 7, Fig. 8 are 700MW Load Rejection of Hydraulic Turbine 30%Effect emulation comparison diagram with control of the present invention.
2. machine and prediction speed governing complex optimum control system are cut in high frequency prediction in hydroelectric power plant's
If the large percentage of area power grid water power capacity, need to take hydroelectric power plant's high frequency predictionCut machine and the control of prediction speed governing complex optimum, control system is shown in Fig. 9.
Complex optimum control device is arranged in booster stations, in order to reduce communication connection, high frequencyThe state of emergency is differentiated the signal electing of logic with regard to earth signal, adopts power plant's high voltage bus voltage letterThe mains frequency signal number obtaining. When mains frequency meets or exceeds 103%, and unit meritThe logical AND of rate Sudden Changing Rate signal, can produce the reliable power station high frequency state of emergency and differentiateSignal. System takes hydroelectric power plant's high frequency prediction to cut machine and prediction speed governing complex optimum control skillArt, in the scope of level of factory, cutting machine amount and power adjustment are carried out combined optimization decision-making, realExecute the machine of cutting fast, and the power prediction target after optimizing is dealt into unit list by fiber optic communicationUnit's side, carries out hydraulic turbine power prediction speed regulating control. This complex optimum control system can beIn the situation of sending end electrical network degree of depth removal of load, further limit Hydropower Unit speed fling lifting, carryThe high frequency of high electrical network is stablized the security with unit.
Claims (5)
1. the power grid high-frequency stability forecast control method based on lonely net trend principle of transfer, itsBe characterised in that: it comprises the steps:
Step 1, collection unit generator power, generating unit speed, mains frequency and overspeed protection are movingMake signal;
Step 2, by the unit generation acc power described in step 1, generating unit speed, mains frequency andOverspeed protection actuating signal generates power grid high-frequency state of emergency judgement letter through compound logic computingNumber; Described compound logic computing is the combination of logical AND, logic OR and logic NOT;
Step 3, according to the judged result of the compound logic computing of step 2, when electrical network judge inWhen the high frequency state of emergency, power grid high-frequency state of emergency signal is carried out to broadening;
Step 4, in the time that high frequency state of emergency signal sends, by the generator power of this moment unitP0Deposit memory in, during power grid high-frequency state of emergency signal broadening, remain unchanged;
Step 5, according to the generator power P in step 4 memory0Calculate power of the assembling unit control orderMark Pobj,
Step 6, during high frequency state of emergency signal broadening, the power prediction control system of unitAccording to power control target P, obj controls the power of the assembling unit.
2. a kind of power grid high-frequency based on lonely net trend principle of transfer according to claim 1Stability forecast control method, is characterized in that: the high frequency state of emergency described in step 2Judging signal, is to protect by the out-of-limit signal of rotating speed, the out-of-limit signal of mains frequency, hypervelocityProtecting OPC actuating signal and unit generation acc power changes in the out-of-limit signal of per unit valuePart signal or all signal carry out compound logic computing and obtain, described compound logicComputing is the combination of logical AND, logic OR and logic NOT;
The out-of-limit signal of generating unit speed: rotating speed is more than or equal to setting value;
The out-of-limit signal of-mains frequency: mains frequency is more than or equal to setting value;
-overspeed protection (OPC) actuating signal: fired power generating unit collection, Hydropower Unit does not makeUse this signal;
-unit generation acc power changes the out-of-limit signal of perunit value: described unit generation acc powerChanging perunit value Δ P isP current time power P, P-ΔtWhen currentQuarter, the power ， ⊿ t of Qian ⊿ t was 5～10 seconds, and Pe is generator rating power, instituteStating the out-of-limit signal of unit generation acc power variation perunit value is that Δ P is greater than upper limit set valueOr be less than lower limit set value.
3. a kind of power grid high-frequency based on lonely net trend principle of transfer according to claim 1Stability forecast control method, is characterized in that: the power of the assembling unit control described in step 5The computing formula of target P obj is:
P0For the unit generation acc power that memory described in step 3 deposits in, k is loadCharacteristic correction coefficient,
U is the per unit value of voltage while measuring after off-the-line, U0For the voltage mark under stable stateValue, dfFor the meritorious frequency influence factor, f is frequency per unit value, and a, b, c are permanentThe proportionality coefficient of impedance, constant current, permanent power section, has a+b+c=1.
4. a kind of power grid high-frequency based on lonely net trend principle of transfer according to claim 1Stability forecast control method, is characterized in that: the unit control system described in step 6When system is Control System for Thermal Power Units, utilize power control target P obj, by fireThe governing system of group of motors, fuel dispensing system, solenoid valve controller and Bypass ControlSystem, controls fast.
5. a kind of power grid high-frequency based on lonely net trend principle of transfer according to claim 1Stability forecast control method, is characterized in that: the unit control system described in step 6When system is Hydropower Unit, utilize power control target P obj, adjust by Hydropower UnitSpeed system is controlled fast, closes with the maximum closing velocity allowing in servo-drive systemClose stator, regulate Hydropower Unit power.
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| GB201710404D0 (en) * | 2017-06-29 | 2017-08-16 | Rolls Royce Plc | Apparatus, methods, computer programs, and non-tranitory computer readable storage mediums for controlling a power generation system |
| CN109038664B (en) * | 2018-08-02 | 2020-05-26 | 山东大学 | High-frequency turn setting method considering fan grid-involvement protection |
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| JPH0287999A (en) * | 1988-08-01 | 1990-03-28 | General Motors Corp (Gm) | Electrical equipment for vehicles with starter/generator induction devices |
| CN101162883B (en) * | 2006-10-12 | 2012-07-04 | 通用电气公司 | Methods and apparatus for electric power grid frequency stabilization |
| CN102946224A (en) * | 2012-12-10 | 2013-02-27 | 贵州电网公司电网规划研究中心 | Thermal power unit power prediction control system for ensuring safety and stability of sending-end electric grid |
| CN203086401U (en) * | 2012-12-10 | 2013-07-24 | 贵州电网公司电网规划研究中心 | Thermal power generating unit power prediction control device capable of guaranteeing safety and stability of export electric network |
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| JPH0287999A (en) * | 1988-08-01 | 1990-03-28 | General Motors Corp (Gm) | Electrical equipment for vehicles with starter/generator induction devices |
| CN101162883B (en) * | 2006-10-12 | 2012-07-04 | 通用电气公司 | Methods and apparatus for electric power grid frequency stabilization |
| CN102946224A (en) * | 2012-12-10 | 2013-02-27 | 贵州电网公司电网规划研究中心 | Thermal power unit power prediction control system for ensuring safety and stability of sending-end electric grid |
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