Summary of the invention
The purpose of the utility model just is that overcoming prior art exists shortcoming and defect, and a kind of primary frequency modulation device of revising based on float frequency difference adjusting and the instruction of variable Rate load is provided.
The technical scheme of the utility model is:
One, the primary frequency modulation device of revising based on float frequency difference adjusting and the instruction of variable Rate load (abbreviation device)
Comprise main process equipment: steam turbine transfers valve opening computing unit, steam turbine DEH to regulate servo card, steam turbine admission adjuster valve group, unit load command calculations unit, coal feeder of boiler command calculations unit, feeder motor, boiler feed pump command calculations unit, steam feed pump, boiler fan command calculations unit and forced draft fan motor;
It is characterized in that: be provided with the primary frequency modulation controller;
Its annexation is:
Steam turbine accent valve opening computing unit, steam turbine DEH are regulated servo card, steam turbine admission adjuster valve group connects successively;
Unit load command calculations unit, coal feeder of boiler command calculations unit, feeder motor connect successively;
Unit load command calculations unit, boiler feed pump command calculations unit, steam feed pump connect successively;
Unit load command calculations unit, boiler fan command calculations unit, forced draft fan motor connect successively;
The primary frequency modulation controller transfers the valve opening computing unit to be connected with unit load command calculations unit with steam turbine respectively.
This primary frequency modulation controller is core with the Industry Control server and disposes the respective peripheral PORT COM.
Two, the primary frequency modulation method of revising based on float frequency difference adjusting and the instruction of variable Rate load (abbreviation method)
This method comprises the following steps:
1. with mains frequency signal f
ActTransfer function equation according to the definition of fast frequency time-delay computing unit
Calculate the mains frequency signal f after obtaining delaying time
k
2. with mains frequency time delayed signal f
kWith mains frequency signal f
ActAsk difference to calculate, obtain instantaneous mains frequency relative variation Δ f
k
3. to Δ f
kAsk absolute calculation, obtain instantaneous mains frequency absolute change amount Δ f
* kThe frequency variation rate judging unit passes through Δ f
* kComputational analysis, obtain the compensation way code C of instantaneous primary frequency modulation system loading instruction through keeping the pulse computing unit
1(0,1);
4. universal frequency time-delay computing unit is according to compensation way code C
1The requirement of (0,1) utilizes the transfer function equation
To real-time power network frequency signal f
ActHandle calculating, the frequency difference that realizes floating is regulated, and obtains mains frequency time delayed signal f
c, and with real-time power network frequency signal f
ActCompare calculating, obtain real-time grid frequency difference signal Δ f
c
5. diversity factor gain calculating unit is according to unit diversity factor slope K
δ, according to equation Δ P
1=K
δ* Δ f
c, calculate real-time unit active power compensation rate Δ P
1, transfer the open and close of valve opening computing unit driving steam turbine to transfer valve through steam turbine, change the admission flow, and then change unit active power, realize the quick compensation of unit active power;
6. diversity factor curvilinear function computing unit is according to unit diversity factor function, in real time to mains frequency f
ActFrequency difference value with standard mains frequency 50Hz is calculated, and obtains the urgent compensation rate Δ of unit active power P
2With the urgent compensation rate Δ of unit active power P behind the unit safety amplitude limit
* 2
7. diversity factor function calculation unit is monitored the real-time grid frequency f simultaneously
ActNumerical value is worked as f
Act>50.2Hz or f
ActDuring<49.0Hz, obtain the urgent compensation way code C of primary frequency modulation system
2(0,1);
8. analog quantity instruction output unit is according to the urgent compensation way code C of primary frequency modulation system
2(0,1) is judged, at C
2(0,1)=1 is o'clock with Δ P
BAssignment is Δ P
* 2, at C
2(0,1)=0 is o'clock with Δ P
BAssignment is Δ P
1
9. through unit load command calculations unit, coal feeder of boiler command calculations unit, boiler feed pump command calculations unit, boiler fan command calculations unit; Calculate boiler coal feeding amount instruction β, boiler feed capacity instruction ω, boiler air quantity instruction μ respectively; Drive coal feeder of boiler, water supply pump, forced draft fan equipment; Change boiler combustion rate, boiler load is complementary with the unit load command request.
The utlity model has following advantage and good effect:
1. adopt the frequency difference of floating to regulate; Can overcome the mains frequency long period departs from the caused primary frequency modulation control system of 50Hz lasting output compensation rate and can't be returned to the drawback in the frequency difference dead band; The lasting fm capacity that can keep unit is for the later stage response provides the frequency modulation allowance;
2. adopt the frequency variation rate judging unit, can be through monitoring the rate of change of mains frequency, the mode of frequency regulation (fast, at a slow speed) of selecting the primary frequency modulation system to be adopted in real time.When mains frequency changed at a slow speed, the primary frequency modulation system can adopt at a slow speed the instruction compensation of loading of frequency modulation pattern, kept the stability of electrical network; When mains frequency changed sudden change because of external load, the primary frequency modulation control system can rely on the variation of the timely load-responsive of fast frequency hopping pattern, increased considerably or reduced unit output, satisfied the frequency modulation requirement of electrical network.Hurry up, the differentiation of frequency modulation pattern at a slow speed, can improve in the net thermal power generation unit to the adaptive capacity of small area mains frequency characteristic, and overcome that the unit load instruction causes along with the frequency difference real-time change increase and decrease phenomenon significantly, fast;
3. introduce the urgent compensation way of primary frequency modulation system, make the primary frequency modulation control system when extreme operating condition appears in mains frequency, can be in time for electrical network provides load support, for mains frequency safety provides effective guarantee.
Embodiment
Further specify below in conjunction with accompanying drawing and embodiment:
One, this primary frequency modulation device (dull joint loop)
1, overall
Like Fig. 2,3, this primary frequency modulation device comprises main process equipment: steam turbine transfers valve opening computing unit 100, steam turbine DEH to regulate servo card 200, steam turbine admission adjuster valve group 201, unit load command calculations unit 300, coal feeder of boiler command calculations unit 400, feeder motor 401, boiler feed pump command calculations unit 600, steam feed pump 601, boiler fan command calculations unit 700 and forced draft fan motor 701;
Its annexation is:
Steam turbine transfers valve opening computing unit 100, steam turbine DEH to regulate servo card 200, steam turbine admission adjuster valve group 201 connects successively, realizes the control of Steam Turbine throttle flow, and then controls Steam Turbine active power;
Unit load command calculations unit 300, coal feeder of boiler command calculations unit 400, feeder motor 401 connect successively, realize boiler according to the unit load command request, corresponding change boiler oil amount;
Unit load command calculations unit 300, boiler feed pump command calculations unit 600, steam feed pump 601 connect successively, realize that boiler according to the unit load command request, provides the feedwater flow that is complementary for the boiler varying duty;
Unit load command calculations unit 300, boiler fan command calculations unit 700, forced draft fan motor 701 connect successively, realize that boiler is according to the unit load command request, for boiler combustion provides suitable air distribution;
Be provided with this primary frequency modulation controller 500;
This primary frequency modulation controller 500 transfers valve opening computing unit 100 to be connected with unit load command calculations unit 300 with steam turbine respectively, realizes the primary frequency modulation controlled function.
This primary frequency modulation controller 500 is core with the Industry Control server and disposes the respective peripheral PORT COM that its software control module comprises fast frequency time-delay computing unit 501, absolute value calculation unit 502, frequency variation rate judging unit 503, maintenance pulse computing unit 504, universal frequency time-delay computing unit 505, diversity factor gain calculating unit 506, diversity factor curvilinear function computing unit 507, compensation limiting unit 508 and analog quantity instruction output select unit 509;
Its interactive relation is:
Fast frequency time-delay computing unit 501, absolute value calculation unit 502, frequency variation rate judging unit 503, keep pulse computing unit 504, universal frequency time-delay computing unit 505 mutual successively, realize that variable Rate load instruction correcting mode judges;
Universal frequency time-delay computing unit 505, diversity factor gain calculating unit 506, analog quantity instruction output select unit 509 are mutual successively, and the frequency difference that realizes floating is regulated variable Rate load instruction correction down;
Diversity factor curvilinear function computing unit 507, compensation limiting unit 508, analog quantity instruct output select unit 509 mutual successively, realize that the load instruction under the emergency work condition is revised.
2, functional block
1) main process equipment
1. steam turbine DEH (digital electrohydraulic control system) is regulated servo card 200 and steam turbine admission adjuster valve group 201
Steam turbine adopts resuperheat, a single shaft and coagulates the formula steam turbine, is equipped with complete all steam turbine admission adjuster valve groups 201.Steam turbine DEH is formed by the senser of electrical principle design, digital circuit (computer) and by amplifier element and hydraulic servomechanism that hydraulic principle designs.
The function of steam turbine admission adjuster valve group 201 is to realize the control of Steam Turbine throttle flow, and then control Steam Turbine active power.
2. the feeder motor 401
Feeder motor 401 comprises the belt-type feeder, and be combined with double-inlet and double-outlet steel ball coal mill, the bowl formula directly blow coal pulverizer or middle storage formula pulverized coal feeder.
The function of feeder motor 401 is to realize boiler according to the unit load command request, corresponding change boiler oil amount.
3. boiler feed pump 601
The boiler feed pump 601 general steam feed pump of two 50%BMCR (boiler maximum continuous rating) and the electrically driven feed pumps of a 30%BMCR of adopting;
Perhaps adopt two 60%BMCR steam feed pumps, perhaps adopt three 50%BMCR electrically driven feed pumps.
The function of boiler feed pump 601 is to realize that boiler according to the unit load command request, provides the feedwater flow that is complementary for the boiler varying duty.
4. the forced draft fan motor 701
Forced draft fan motor 701 adopts the axial flow blower of two 50%BMCR.
The function of forced draft fan motor 701 is to realize that boiler is according to the unit load command request, for boiler combustion provides suitable air distribution.
5. steam turbine transfers valve opening computing unit 100 and unit load command calculations unit 300 to be control system software configuration program, and its function is to receive the unit load instruction, carry out corresponding operation after, again to subordinate's controller sending controling instruction.
6. steam turbine DEH is regulated servo card 200, coal feeder of boiler command calculations unit 400, boiler feed pump command calculations unit 600 and boiler fan command calculations unit 700 and is Programmable Logic Controller (PLC), and its function is to receive higher level's control command to carry out driving the operation of actuator of subordinate again after the corresponding data processing.
2) this primary frequency modulation controller 500
1. fast frequency time-delay computing unit 501 is: according to the real-time power network frequency signal, and through inertial element, the mains frequency after being delayed time fast;
2. absolute value calculation unit 502 is: the difference of the mains frequency signal after real-time power network frequency signal and the quick time-delay is carried out absolute value handle;
3. frequency variation rate judging unit 503 is: the amplitude to instantaneous mains frequency variable quantity absolute value is judged, surpasses the threshold value of setting and promptly triggers the maintenance pulse;
4. keep pulse computing unit 504 to be:, to generate the compensation way code of instantaneous primary frequency modulation system loading instruction, and code is carried out alternately with other unit with the mode of pulse signal according to the predefined burst length;
5. universal frequency time-delay computing unit 505 is: according to the requirement of the compensation way code of instantaneous primary frequency modulation system loading instruction, the real-time power network frequency is carried out computing, realize the frequency difference regulatory function of floating;
6. diversity factor gain calculating unit 506 is: according to the unit diversity factor, according to gain equation, calculate real-time unit active power compensation rate;
7. diversity factor curvilinear function computing unit 507 is: according to unit diversity factor function, in real time mains frequency is calculated with the frequency difference value of standard mains frequency 50Hz, obtain the urgent compensation rate of unit active power; Monitor the real-time power network frequency simultaneously, generate the urgent compensation way code of corresponding primary frequency modulation system according to its scope;
8. compensating limiting unit 508 is: the 507 urgent compensation rates of unit active power that calculate are carried out amplitude limiting processing;
9. analog quantity instruction output select unit 509 is: according to the urgent compensation way code of primary frequency modulation system; Under normal circumstances with unit active power compensation rate as output; Alternately to unit load command calculations unit; In case of emergency with the urgent compensation rate of unit active power as output, alternately to unit load command calculations unit.
Like Fig. 4, this primary frequency modulation controller 500 adopt with skeleton-grid be the dcs (DCS) of structure as hardware platform, and controller is carried out programmed, thereby realizes desired primary frequency modulation function with specific software.
Present domestic DCS major vendor has: Shanghai Xinhua, Nanjing section are far away, Hangzhou excellent steady, SUPCON, Hollysys, Weisheng, Zhejiang, Ziyi Stocks Trading Co, Luneng control, state's electricity intelligence is dark, Shanghai is Chinese-language, in the happy China in Shanghai, Zhejiang from etc.;
External DCS major vendor has: western room (Ai Mosheng), FOXBORO, ABB, Siemens, Honeywell, Yokogawa, Rockwell, Yamatake-Honeywell co., Ltd., FISHER-ROSEMOUNT company etc.
The grid of DCS has several big advantages: at first, it can satisfy the requirement of real-time, can in the time dimension of confirming, accomplish the transmission of information.Which kind of situation no matter the time dimension of said here " confirming " be meant under, and information transmits and can both in this time dimension, accomplish, and this time dimension then is to confirm according to the real-time requirement of Be Controlled process; Secondly, after it adopted the network topology structure of dual bus, annular or dual star, grid was very reliable, and no matter under any circumstance, network service can not interrupted; The 3rd, in order to satisfy the requirement of system expansibility, the maximum node quantity that can insert on the grid should be than the big several times of number of nodes of reality use.Like this, can increase new node at any time on the one hand, also can make grid run on lighter communication load state on the other hand,, and have very strong online network reconfiguration function with real-time and the reliability of guaranteeing system.
The DCS system adopts the network node of fully on-the-spot I/O being handled and realizes Direct Digital control (DDC) function.Among the general cover DCS on-the-spot I/O control station to be set, in order to I/O and the controlled function of sharing whole system.So both can avoid causing the inefficacy of whole system, improve system reliability, and also can make each website share data acquisition and controlled function, help improving the performance of whole system because a website loses efficacy.
DCS utilizes the engineer station to carry out configuration, configuration work and online system monitor, the control of off-line, the network node of maintenance; Its major function provides carries out configuration to DCS; The tool software of configuration effort (being configuration software); And the ruuning situation of when the DCS on-line operation, keeping watch on each node on the DCS network in real time, make the system engineer DCS is under the best operating state at any time through the setting of the timely Adjustment System configuration of engineer station and some system parameterss.
3, this device operation principle
In order to realize the desired primary frequency modulation function of net accent, the thermal power generation unit has all designed the primary frequency modulation control system.Like Fig. 5 (power system frequency-power relation curve), electric power system balance movement point is a, if the load in the system increases Δ P
L, then total load static frequency characteristic becomes P
L1, suppose the equal regulator-free of at this moment intrasystem all units, the input power of unit is constant to be P
T, and equal P
L, then system frequency will descend, and the active power that load is taken reduces gradually.
Rely on the Load Regulation effect, system reaches new balance, and operating point moves on to the b point, and the frequency stabilization value drops to f
3, the active power that system load is taken still is original P
LValue.In this case, exemplary frequency deviation values Δ f is decided by Δ P
LThe size of value generally is sizable.
But in fact each thermal power generation unit all is designed with the primary frequency modulation control device, and after system load increased, and frequency begins to descend, the primary frequency modulation control system was started working, the action of driving power adjuster, the input power P of increase unit
TAfter after a while, in the stable operation of c point, frequency is f
2, the power that system load is at this moment taken is P
L2, less than desired power P under the rated frequency
L1The frequency deviation f of this moment is much little when wanting the specific power adjuster, and this regulating action is commonly referred to primary frequency modulation.
Two, method
1, the related work process of this method
According to the situation of power system operation, can the course of work of this primary frequency modulation controller 500 under the corresponding operating mode be discussed respectively with frequency according to the different numerical interval division.
1) slow rate load instruction correcting mode
The work operating mode of this mode is: mains frequency fluctuates between 49~50.2Hz, and at a time, mains frequency descends or rises because of load user's increase or minimizing constantly, and decline or climbing speed<0.01Hz/min.
At this moment, mains frequency signal f after the time-delay that calculated of fast frequency time-delay computing unit 501
kWith the real-time grid frequency f
ActDifference be instantaneous mains frequency relative variation Δ f
k, 502 couples of Δ f of absolute value calculation unit
kAfter carrying out signed magnitude arithmetic(al), export instantaneous mains frequency absolute change amount Δ f
* kCarry out alternately with frequency variation rate judging unit 503.Owing to Δ f this moment
* k<0.01Hz/min keeps pulse computing unit 504 to judge the compensation way code C of instantaneous primary frequency modulation system loading instruction through the computing meeting
1(0,1) is status word " 0 ", after universal frequency time-delay computing unit 505 receives " 0 " status word, carries out computing according to the pre-designed time constant of inertial element at a slow speed.Such working method promptly is called slow rate load instruction correcting mode.
Aspect main operational loop, the real-time grid frequency f
ActAt first alternately to universal frequency time-delay computing unit 505, obtain the mains frequency time delayed signal f after the computing
c, and with the real-time grid frequency f
ActAsk difference operation, obtain electrical network frequency difference signal Δ f
cThis frequency difference is different from traditional account form based on the 50Hz frequency reference, but Real-time and Dynamic changes certain frequency difference amount that produces, and therefore is called the frequency difference regulative mode that floats.
506 of diversity factor gain calculating unit are according to unit diversity factor gain slope K
5, calculate frequency difference signal Δ f
cPairing real-time unit active power compensation rate Δ P
1Δ P
1The steam turbine that directly is added to is on the one hand transferred valve opening computing unit 100, and 201 actions of driving steam turbine admission adjuster valve group increase steam turbine admission flow in advance, form the quick response of unit load; On the other hand alternately to unit load command calculations unit 300; And then drive feeder motor 401, steam feed pump 601, forced draft fan motor 701; Thereby change boiler and keep follow-up load required coal amount, the water yield, air quantity; After guaranteeing the primary frequency modulation action, unit can get into corresponding steady working condition.
The characteristics of this mode are; Have only a spot of frequency modulation compensation rate to participate in the adjusting of unit; Purpose is to satisfy mains frequency (in the process of speed<0.01Hz/min), the primary frequency modulation system of each unit finely tunes the compensation of network load deviation in the net slowly descending or rise.
2) rapid rate load instruction correcting mode
The work operating mode of this mode is: mains frequency f
ActBetween 49~50.2Hz, fluctuate, at a time, mains frequency f
ActDescend or rise because of load user's increase or minimizing, and decline or climbing speed>0.01Hz/min.
At this moment, mains frequency signal f after the time-delay that calculated of fast frequency time-delay computing unit 501
kWith the real-time grid frequency f
ActDifference be instantaneous mains frequency relative variation Δ f
k, 502 couples of Δ f of absolute value calculation unit
kAfter carrying out signed magnitude arithmetic(al), export instantaneous mains frequency absolute change amount Δ f
* kCarry out alternately with frequency variation rate judging unit 503.Owing to Δ f this moment
* k>0.01Hz/min keeps pulse computing unit 504 to judge the compensation way code C of instantaneous primary frequency modulation system loading instruction through the computing meeting
1(0,1) is status word " 1 ", after universal frequency time-delay computing unit 505 receives the one state word, and can be with the time-delay mains frequency f of output
cNumerical value according to a last execution cycle keeps, and the retention time is provided with in this unit in advance.Such working method promptly is called rapid rate load instruction correcting mode.
Because the output signal f of universal frequency time-delay computing unit 505
cRemain unchanged, in follow-up a period of time, frequency difference signal Δ f
cNumerical value can As real-time mains frequency f
ActProgressively decline or rise increase always, cause the real-time unit active power compensation rate Δ P that is exported of diversity factor gain calculating unit 506
1Absolute value increases always.Therefore, compare with slow rate load instruction correcting mode, in the unit interval, unit provides more load responding to the variation of mains frequency, has realized the fast frequency response.
The characteristics of this mode are: the primary frequency modulation system thinks that mains frequency descends or climbing speed is too fast; Therefore provide more frequency modulation compensation rate to participate in the adjusting of unit; Purpose is to satisfy mains frequency descending fast or rising (in the process of speed>0.01Hz/min); Rapid compensation network breach load of the primary frequency modulation system of each unit or quick-release surplus electric weight in the net, the decline of relieving system frequency or climbing speed.
3) urgent load instruction correcting mode
The work operating mode of this mode is: mains frequency f
ActAt a time, bust is to perhaps jumping to more than the 50.2Hz below the 49.0Hz
At this moment, diversity factor curvilinear function computing unit 507 calculates this moment mains frequency f according to unit diversity factor characteristic curve on the one hand
ActWith the deviation between the mains frequency fiducial value 50Hz, and calculate the pairing unit active power of this frequency departure compensation rate Δ P
2, mutual with compensation limiting unit 508 then, realize the safe amplitude limit function of unit active power compensation, finally obtain the urgent compensation rate Δ of unit active power P behind the unit safety amplitude limit
* 2
On the other hand, diversity factor curvilinear function computing unit 507 is with the urgent compensation way code C of primary frequency modulation system
2(0,1) to status word " 1 " is alternately to analog quantity instruction output select unit 509, with its output Δ P
BAssignment is Δ P
* 2And alternately to unit load command calculations unit 300, and then drive feeder motor 401, steam feed pump 601, forced draft fan motor 701, keep follow-up load required coal amount, the water yield, air quantity thereby change boiler; After guaranteeing the primary frequency modulation action, unit can get into corresponding steady working condition.
The characteristics of this mode are: in case mains frequency is reduced to below the 49Hz or risen to 50.2Hz; The primary frequency modulation controller thinks that promptly the variation of mains frequency this moment has exceeded safe range; Transfer the primary frequency modulation control mode to emergency mode immediately; Through increasing considerably or reducing unit active power, compensation or the unnecessary electric weight of quick-release electrical network make mains frequency return to range of normal value fast.
2, software design
Software operational flowchart when Fig. 6 is 500 work of primary frequency modulation controller.
The software computing is carried out according to following steps:
The 0th: the computing of this cycle begins;
The 1st: the real-time grid frequency variation rate calculates Δ f
k(the corresponding method step 1., 2.)
The 2nd: absolute calculation, try to achieve Δ f
* k(the corresponding method step 3.)
The the 3rd: carry out Δ f
* k<0.01Hz/min judges, is then to get into the 4th step, otherwise jumps to the 6th step; (the corresponding method step 3.)
The the 4th: with C
1(0,1) status word reset;
The the 5th: utilize transfer function f
c(t)=1/ (1+20s) * fact (t) calculates f
c, and jumped to for the 8th step; (the corresponding method step 4.)
The the 6th: with C
1(0,1) status word set;
The the 7th: with f
c(t) kept last execution cycle value N second;
The the 8th: with equation Δ f
c=fact-f
cCalculate frequency difference; (the corresponding method step 4.)
The the 9th: by frequency difference Δ f
cCalculate primary frequency modulation compensation power Δ P
1(the corresponding method step 5.)
The the 10th: carry out f
Act<49.0Hz or f
Act>50.2Hz judges, is then to get into the 11st step, otherwise jumps to the 12nd step; (the corresponding method step 7.)
The the 11st: with Δ P
BAssignment is Δ P
1, jump to the 15th step; (the corresponding method step 8.)
The the 12nd: calculate Δ P according to unit diversity factor characteristic curve
2(the corresponding method step 6.)
The 13rd: the amplitude limit computing obtains Δ P
* 2(the corresponding method step 6.)
The the 14th: with Δ P
BAssignment is Δ P
* 2, get into the 15th step; (the corresponding method step 8.)
The 15th: the computing of this cycle finishes.
Three, test result
Fig. 7 is the real-time unit major parameter data that obtained being applied in the engineering test based on the primary frequency modulation control system that the frequency difference of floating is regulated and the varying duty instruction is revised.This system has shown the high frequency to the small area mains frequency, the adaptability of fluctuation characteristic in actual turbo generator set puts into operation process, and can make the primary frequency modulation ability of unit satisfy the dispatching of power netwoks index request simultaneously.