CN102570497A - Method for controlling thermal generator set in isolated network operation of power grid - Google Patents
Method for controlling thermal generator set in isolated network operation of power grid Download PDFInfo
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- CN102570497A CN102570497A CN2011104176269A CN201110417626A CN102570497A CN 102570497 A CN102570497 A CN 102570497A CN 2011104176269 A CN2011104176269 A CN 2011104176269A CN 201110417626 A CN201110417626 A CN 201110417626A CN 102570497 A CN102570497 A CN 102570497A
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Abstract
The invention discloses a method for controlling a thermal generator set in the isolated network operation of a power grid. The grading of an isolated network is taken into account, and a primary frequency control strategy is improved and subjected to grading control. In addition, the action of acceleration of a rotor is introduced into predictive control over the generator set, and the regulation amplitude of the generator set is enhanced before the protection action of the generator set. By the method, the frequency fluctuation of the power grid can be reduced as fast as possible when the power grid enters the isolated network operation, and heat accumulation and automatic regulation functions of the thermal generator set are fully utilized within a short time to avoid the further spreading of an accident.
Description
Technical field
The present invention relates to a kind of control method of thermal power generation unit, especially relate to the control method of the thermal power generation unit of a kind of electrical network when lonely network operation.
Background technology
In operation of power networks,, form the region operation of power networks of part power supply point owing to cause the circuit pack tripping under the initiations such as system oscillation, natural calamity, electric switch malfunction or fault.At this moment, the section electrical network is also referred to as lonely net, mains frequency, unit operation operating mode fluctuation in the lonely net.In this case, existing primary frequency modulation control has been insignificant to the contribution of orphan's net, generally all is to rely on unit overspeed protection means to come significantly to reduce steam turbine to exert oneself with the frequency of the lonely net of fast and stable.
When electrical network breaks down; Frequency fluctuation was violent when regional power grid and the major network off-the-line with part power supply point got into lonely network operation, caused the turbine speed fluctuation, even can make unit overspeed protection action; The power of the assembling unit reduces fast; Thereby make regional power grid power, frequency instability, finally might make regional power grid collapse the occurrence of large-area power outage.
The overspeed protection of most fired power generating unit all was arranged on 3090 rev/mins in the electrical network in the past; Get in the lonely network operation process at electric network from collapsing; When if lonely net frequency surpasses the 51.5Hz of 3090 rev/mins of correspondences; All unit overspeed protections are moved simultaneously, and this control very easily makes frequency significantly vibrate.At present; For tackling the special operation condition of lonely network operation; There are some areas to carry out the strategy of unit overspeed protection grading control; Both big electrical network was divided into some sections, and in the section, carried out the classification of overspeed protection according to the difference of unit capacity, importance difference in electrical network, the part of generating units overspeed protection is reduced to 3060 rev/mins, part of generating units overspeed protection and is increased to 3120 rev/mins etc.Even but adopt this control strategy; When the orphan nets the 51Hz that frequency do not reach 3060 rev/mins of correspondences; The interior unit of lonely net is not brought into play quick adjustment steady load net and is acted on frequently, when reaching unit overspeed protection operating value, unit and lonely net is also had very big impact.
Primary frequency modulation is meant that the paired running unit is according to the automatic distribution load of the static characteristic of self in the electrical network; In the adjustment of electrical network; Primary frequency modulation can be thought temporary transient; Frequency modulation frequency modulation also has little time fully to guarantee the balance between supply and demand of electric network active power after the electrical network load variations, and it is unlikely excessive and cause serious consequence temporarily to guarantee that by primary frequency modulation mains frequency changes.The setting that primary frequency modulation dead band and amplitude limit are common such as Fig. 1; The dead time is ± 2r/min; Diversity factor is 5%, and general load change is limited in 6%～10% rated load, and the amplitude of fired power generating unit rated load below 200MW is 10%; Amplitude between 200MW～500MW is 8%, and the above amplitude of 500MW is 6%.
DEH regulation and control system transfer function principle is seen Fig. 2; The primary frequency modulation amount is superimposed upon the given aperture that goes up as the steam turbine pitch of unit, and load that generating unit speed is corresponding with the speed discrepancy of 3000r/min or pitch aperture become a module among the DEH with the form of difference functions.
In mains frequency fluctuation, the adjustment that unit is automatically loaded according to self primary frequency modulation characteristic is carried out frequency modulation frequency modulation according to the instruction of dispatching of power netwoks more simultaneously and is kept the stable of electrical network to reduce the deviation of frequency.But existing control strategy can't be resisted the big ups and downs of mains frequency when electrical network gets into lonely netted condition operation.
The modern power network scale enlarges day by day; The loss that risk that the while electrical network faces and fault cause is also increasing; The electrical network icing accident of province such as China Zhejiang, Hunan, Guizhou just causes the lonely network operation of large-area power failure and some areas like in January, 2008, brings tremendous loss to national economy.
Also have; Especially wind-powered electricity generation is fast-developing for the multiple new forms of energy of China at present; Wind-powered electricity generation installed capacity accumulative total in 2009 9196.16MW in the Inner Mongol, west area, accumulative total 13858.01MW in 2010, the wind-powered electricity generation energy output accounts for whole energy output and surpasses 10%; Accumulative total 1187.95MW in 2009 in Gansu, accumulative total 4943.95MW in 2010.Maritime provinces is also being greatly developed offshore wind farm, and according to the planning of the new forms of energy of National Energy Board, wind-powered electricity generation will keep the fast-developing impetus in China 10 years, 20 years, and the wind-powered electricity generation installed capacity accounts for total installation of generating capacity in some areas ratio also can rise.
But the extensive off-grid accident of wind-powered electricity generation unit constantly takes place recently; Like April 17; Guazhou County, Gansu synergism wind-powered electricity generation company case of dry river mouth west second wind energy turbine set becomes the high-pressure side cable end and punctures; Cause serial reaction, cause 702 unit off-grids of 15 wind energy turbine set, loss exert oneself that area, the preceding Jiuquan of the accident that accounts for wind-powered electricity generation exerts oneself 54.17%.April 25, wind-powered electricity generation base, Jiuquan has an accident, thousands of typhoon machine off-grids, and the loss wind-powered electricity generation is exerted oneself 153.5 ten thousand kilowatts.So the large-scale wind power unit is concentrated off-grid, causes network system voltage, frequency to fluctuate widely.Direct threats is moved to power system safety and stability, even causes electric network from collapsing to form a plurality of lonely network operations.
Summary of the invention
Technical problem to be solved by this invention; Just provide the thermal power generation unit control method of a kind of electrical network when lonely network operation; It can reduce the fluctuation of mains frequency as early as possible when electrical network gets into lonely network operation; Make full use of the accumulation of heat and automatic regulatory function of fired power generating unit at short notice, avoid the further expansion of accident.
Solve the problems of the technologies described above, the technical scheme that the present invention takes is:
The thermal power generation unit control method of a kind of electrical network when lonely network operation may further comprise the steps:
1) in the moment that gets into lonely net, calculate rotor acceleration according to the spinner velocity that detects, be converted into corresponding pitch actuating quantity be superimposed upon unit given on;
2) lonely net is carried out classification, when the mains frequency fluctuation is within ± 60 rev/mins (containing 60 rev/mins), adopt improved primary frequency modulation grading control strategy; When the mains frequency fluctuation surpasses ± 60 rev/mins, unit overspeed protection classification action when adopting high frequency: net the interior pre-set hierarchy plan of unit according to the orphan and successively move, cut network load according to pre-set off-load scheme during low frequency;
Being scaled described in the step 1): the interpolating function module of the corresponding pitch aperture of rotor acceleration of stack is in unit is given in DEH control;
Step 2) the improved primary frequency modulation hierarchy plan described in is: increased the primary frequency modulation control of 15r/min～60r/min in the control blind area of original 11r/min～60r/min, in increasing the zone, kept 5% diversity factor.
Beneficial effect: according to the characteristics of orphan net, this programme is through netting the consideration that classification is carried out in frequency fluctuation to the orphan, and then on control strategy, takes the strategy of primary frequency modulation grading control, can reach and accelerate the stable effect of lonely net.
Description of drawings
Fig. 1 for existing primary frequency modulation dead band and amplitude limit common sketch map is set;
Fig. 2 is existing DEH regulation and control system transfer function schematic diagram;
Fig. 3 is the primary frequency modulation control sketch map after improving;
Fig. 4 is a Steam Turbine rotor acceleration sketch map;
Fig. 5 is rotor acceleration and pitch regulated quantity graph of a relation;
Fig. 6 is the DEH regulation and control system transfer function schematic diagram after improving.
Embodiment
The thermal power generation unit control method embodiment of electrical network of the present invention when lonely network operation may further comprise the steps:
1) in the moment that gets into lonely net, calculate rotor acceleration according to the spinner velocity that detects, be converted into corresponding pitch actuating quantity be superimposed upon unit given on;
2) lonely net is carried out classification, when the mains frequency fluctuation is within ± 60 rev/mins, adopt improved primary frequency modulation grading control strategy; When the mains frequency fluctuation surpasses ± 60 rev/mins, unit overspeed protection classification action when adopting high frequency: net the interior pre-set hierarchy plan of unit according to the orphan and successively move, cut network load according to pre-set off-load scheme during low frequency;
Being scaled described in the step 1): the interpolating function module of the corresponding pitch aperture of rotor acceleration of stack is in unit is given in DEH control.
Step 2) the improved primary frequency modulation hierarchy plan described in is: increased the primary frequency modulation control of 15r/min～60r/min in the control blind area of original 11r/min～60r/min, in increasing the zone, kept 5% diversity factor.
Specify as follows:
At first; Lonely net is carried out classification, when the mains frequency fluctuation surpasses ± 60 rev/mins, think that lonely net gets into severe; Unit overspeed protection classification action when adopting high frequency, in netting according to the orphan the pre-set hierarchy plan of unit successively move, the strategy of high frequency cutter and UFLS; When the mains frequency fluctuation was within ± 60 rev/mins, it was moderate to think that lonely net gets into, and unit overspeed protection does not at this moment reach the condition of action, is the fast and stable mains frequency, adopts primary frequency modulation grading control strategy.
Primary frequency modulation grading control strategy is exactly the sphere of action that on original primary frequency modulation basis, enlarges primary frequency modulation; The primary frequency modulation control of 15r/min～60r/min, the diversity factor of maintenance 5% in increasing the zone have been increased in the control blind area of original 11r/min～60r/min according to the classification of orphan net.Referring to Fig. 3:
In order to strengthen the control of unit, utilize unit get into lonely network operation moment the turbine rotor acceleration variation carry out Prediction Control.The differential equation of motion that the turbo generator set stiff rotor sways is:
In the formula:
is for acting on epitrochanterian resultant moment;
is each item moment of resistance sum;
is Steam Turbine Driven moment;
is the moment of inertia of rotor;
and
is the angle and the angular speed of rotor rotation, and
is exactly the acceleration of rotor.
When electrical network when getting into lonely net; Unit sends in the lonely net power and laod unbalance; Make rotor acceleration occur; And along with the big or small acceleration of power and laod unbalance also with linear change, the maximum speed that reaches balance condition at unit changes too, sees Fig. 4: produce different acceleration a at different torque difference effect lower rotor parts
3>a
2>a
1, the highest net that reaches when stable is f frequently
3>f
2>f
1
Utilize this characteristic of unit rotor acceleration, can be in the moment that gets into lonely net, other control strategy is still controlled Puiescent, inoperative the time in advance; Utilize detected rotor acceleration be converted into corresponding pitch actuating quantity be superimposed upon unit given on; Along with the adjusting that the orphan nets interior unit, the power of the interior unit of lonely net and load be balance gradually, and rotor acceleration also diminishes gradually; Effect weakens, and the adjusting of whole system has been played differential regulated.Can realize during interpolating function module that can be through the corresponding pitch aperture of a rotor acceleration that superposes in DEH control and unit are given.The principle schematic of newly-increased module is seen Fig. 5, and wherein rotor acceleration a0 and ak can calculate according to the load rejection test calculated value of every unit, and corresponding regulated quantity xk can be 6%～8% or a corresponding pitch opening value of rated load.
DEH regulation and control system transfer function schematic diagram improvement part is seen left side among Fig. 6:
Can find out from new control strategy; When the moment of the lonely net of electrical network entering, the rotor acceleration module is judged according to the severe of orphan's net, is worked immediately unit is controlled; Rising along with generating unit speed progressively tightens control according to the grading control principle primary frequency modulation module of primary frequency modulation afterwards; The Load Regulation intensity maximum of unit is original 6 times, and the maximal regulated amount reaches 36% of rated load, the fluctuation in the time of can significantly reducing electrical network and get into lonely network operation; Reduce the possibility that accident enlarges, race against time for dispatching as early as possible the stable electrical network operation.
Key point of the present invention is: adopt the consideration of lonely net being carried out classification, the primary frequency modulation control strategy is improved do grading control.In addition, introduce the effect of rotor acceleration, unit is carried out Prediction Control, before the generator protection action, strengthen the amplitude that unit is regulated.
Claims (1)
1. the thermal power generation unit control method of an electrical network when lonely network operation may further comprise the steps:
1) in the moment that gets into lonely net, calculate rotor acceleration according to the spinner velocity that detects, be converted into corresponding pitch actuating quantity be superimposed upon unit given on;
2) lonely net is carried out classification, when the mains frequency fluctuation is within ± 60 rev/mins (containing 60 rev/mins), adopt improved primary frequency modulation grading control strategy; When the mains frequency fluctuation surpasses ± 60 rev/mins, unit overspeed protection classification action when adopting high frequency: net the interior pre-set hierarchy plan of unit according to the orphan and successively move, cut network load according to pre-set off-load scheme during low frequency;
Being scaled described in the step 1): the interpolating function module of the corresponding pitch aperture of rotor acceleration of stack is in unit is given in DEH control;
Step 2) the improved primary frequency modulation hierarchy plan described in is: increased the primary frequency modulation control of 15r/min～60r/min in the control blind area of original 11r/min～60r/min, in increasing the zone, kept 5% diversity factor.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103147804A (en) * | 2013-02-20 | 2013-06-12 | 哈尔滨汽轮机厂有限责任公司 | One-step frequency modulation control method for steam turbine |
| CN104009474A (en) * | 2014-06-17 | 2014-08-27 | 贵州电力试验研究院 | Primary frequency modulation setting method used under condition of isolated power grid |
| CN104201668A (en) * | 2014-08-13 | 2014-12-10 | 中国南方电网有限责任公司 | Isolated grid operation stabilization control method for regional weak tie power grid |
| CN104779615A (en) * | 2015-04-29 | 2015-07-15 | 酒泉钢铁(集团)有限责任公司 | Grid frequency regulation method for reducing loads of generator set rapidly |
| CN106300442A (en) * | 2016-09-20 | 2017-01-04 | 国网浙江省电力公司电力科学研究院 | A kind of control method of thermal power generation unit responsive electricity grid low frequency fault accommodation |
| CN108964025A (en) * | 2018-06-29 | 2018-12-07 | 国电南瑞科技股份有限公司 | A kind of asynchronous power grid AGC control method containing a plurality of DC line |
| CN112564169A (en) * | 2020-12-14 | 2021-03-26 | 济宁华源热电有限公司 | Thermal power generation primary frequency modulation system and method based on load feedback |
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| JPH07224752A (en) * | 1994-02-08 | 1995-08-22 | Kubota Corp | Voltage adjusting device for small hydraulic power generator |
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| JPH07224752A (en) * | 1994-02-08 | 1995-08-22 | Kubota Corp | Voltage adjusting device for small hydraulic power generator |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103147804A (en) * | 2013-02-20 | 2013-06-12 | 哈尔滨汽轮机厂有限责任公司 | One-step frequency modulation control method for steam turbine |
| CN104009474A (en) * | 2014-06-17 | 2014-08-27 | 贵州电力试验研究院 | Primary frequency modulation setting method used under condition of isolated power grid |
| CN104009474B (en) * | 2014-06-17 | 2021-11-02 | 贵州电网有限责任公司 | Primary frequency modulation setting method used in isolated grid mode of power grid |
| CN104201668A (en) * | 2014-08-13 | 2014-12-10 | 中国南方电网有限责任公司 | Isolated grid operation stabilization control method for regional weak tie power grid |
| CN104779615A (en) * | 2015-04-29 | 2015-07-15 | 酒泉钢铁(集团)有限责任公司 | Grid frequency regulation method for reducing loads of generator set rapidly |
| CN104779615B (en) * | 2015-04-29 | 2017-10-03 | 酒泉钢铁(集团)有限责任公司 | A kind of net frequency modulation adjusting method of generating set fast cutback |
| CN106300442A (en) * | 2016-09-20 | 2017-01-04 | 国网浙江省电力公司电力科学研究院 | A kind of control method of thermal power generation unit responsive electricity grid low frequency fault accommodation |
| CN106300442B (en) * | 2016-09-20 | 2019-05-28 | 国网浙江省电力公司电力科学研究院 | A kind of control method of thermal power generation unit responsive electricity grid low frequency fault accommodation |
| CN108964025A (en) * | 2018-06-29 | 2018-12-07 | 国电南瑞科技股份有限公司 | A kind of asynchronous power grid AGC control method containing a plurality of DC line |
| CN108964025B (en) * | 2018-06-29 | 2021-07-02 | 国电南瑞科技股份有限公司 | AGC control method for asynchronous power grid comprising multiple direct current lines |
| CN112564169A (en) * | 2020-12-14 | 2021-03-26 | 济宁华源热电有限公司 | Thermal power generation primary frequency modulation system and method based on load feedback |
| CN112564169B (en) * | 2020-12-14 | 2021-10-26 | 济宁华源热电有限公司 | Thermal power generation primary frequency modulation system and method based on load feedback |
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Application publication date: 20120711 |