CN103066618A - Access system and island monitoring method of thin film solar photovoltaic generating station - Google Patents
Access system and island monitoring method of thin film solar photovoltaic generating station Download PDFInfo
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- CN103066618A CN103066618A CN2012105242351A CN201210524235A CN103066618A CN 103066618 A CN103066618 A CN 103066618A CN 2012105242351 A CN2012105242351 A CN 2012105242351A CN 201210524235 A CN201210524235 A CN 201210524235A CN 103066618 A CN103066618 A CN 103066618A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/40—Arrangements for reducing harmonics
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Abstract
The invention discloses an access system and an island monitoring method of a thin film solar photovoltaic generating station based on thin film solar photovoltaic generation micro-grid access technical field. The system comprises a voltage parallel type filter and an island detecting unit. The voltage parallel type filter is connected between the solar photovoltaic generating station and a grid-connected inverter in series. The island detecting unit is connected between the solar photovoltaic generating station and a bus in series. The island monitoring method comprises that common connecting point voltage is subjected to feedforward through the island detecting unit; through preset algorithm, a current amplitude disturbance quantity is output; a solar photovoltaic generating station output current is computed; and power interruption between the solar photovoltaic generating station and a bus power grid is determined. Harmonic suppression and island detection of the grid-connected inverter of a grid-connected photovoltaic power generation system are achieved.
Description
Technical field
The invention belongs to the microgrid access technology field of based thin film solar energy power generating, relate in particular to a kind of thin film solar photo-voltaic power generation station connecting system and isolated island monitoring method thereof.
Background technology
Carry out the grid-connected impact research on electrical network of large capacity, research has operability, comprehensively, effectively be incorporated into the power networks administrative standard and technical specification, from standardized administration and the reliable angle of technology grid-connected photovoltaic power generation system is claimed, under the prerequisite that guarantees the photovoltaic generating system quality of power supply, reliability and fail safe, to farthest utilizing the solar power generation resource significant.
Photovoltaic generation has from net and the two kinds of working methods that are incorporated into the power networks.In the past, because the production cost of solar cell is high, the photovoltaic generation majority is used to remote areas without electricity, and in the majority with the middle mini system that the family is used and the village is used, and all belongs to from net type user.But in recent years, great variation has occured in photovoltaic industry and market thereof, beginning is strided forward fast by the direction that outlying rural area progressively generates electricity by way of merging two or more grid systems to the city, photovoltaic building is integrated, solar energy oneself through approved it will will be " alternative energy source " of future generation by the role of " replenish the energy " globally.
China is in and switches to a market economy and flourish period, but energy problem is severe, owing to using in a large number fossil energy, environment continues to worsen in the city.That the side HO of the World Health Organization in 2000) announces pollutes in ten the most serious big cities in the world, and China has accounted for eight, and wherein Beijing occupy the 7th.Greatly developing parallel network power generation will help to address this problem as early as possible.Relevant leading department of country has begun to attach great importance to, and at first is that the Ministry of Science and Technology has planned step by step relevant scientific and technical innovation research, demonstration and the industrialization process thereof of propelling." eight or five " and the enforcement period of the ninth five-year plan have been listed " State Commission for Restructuring the Economic Systems " to " photovoltaic roof grid-connected system " in, have built up respectively the photovoltaic roof grid-connected system of 1OOKWp, 17KWp, 7KWp5KWp in Shenzhen and Beijing and have successfully realized generating electricity by way of merging two or more grid systems.The single roof type thin film solar photovoltaic generating system of largest domestic begins to generate electricity by way of merging two or more grid systems in Shenzhen a few days ago.This project has been included into country's " golden sun " demonstration project catalogue, and expectation will obtain 1,500 ten thousand yuan subsidy fund.
Up to the present, the key technology of China's parallel network power generation and equipment is still mainly from import, but in the face of so huge domestic demands, develops in a down-to-earth manner the relevant high-tech with self-knowledge property right, and then realize its industrialization, be instant thing.
Summary of the invention
The object of the invention is to, a kind of thin film solar photo-voltaic power generation station connecting system and isolated island monitoring method thereof are provided.
To achieve these goals, the technical scheme of the present invention's proposition is that a kind of thin film solar photo-voltaic power generation station connecting system is characterized in that described system comprises voltage parallel mode filter and isolated island detecting unit;
Described voltage parallel mode filter is connected in series between solar photo-voltaic power generation station and the combining inverter, is used for suppressing the harmonic wave that combining inverter produces; Described voltage parallel mode filter is comprised of the instruction current computing module that is linked in sequence and offset current generation module; Described instruction current computing module is for detection of the harmonic wave in the target compensation electric current and reactive power, and the command signal of generation offset current; Offset current generation module produces actual offset current for the command signal of the offset current that draws according to the instruction current computing module;
Described isolated island detecting unit is connected in series between solar photo-voltaic power generation station and the bus, is used for the output current of monitoring solar photo-voltaic power generation station, thus determine solar photo-voltaic power generation station whether with the bus grid cut-off.
A kind of isolated island monitoring method of thin film solar photo-voltaic power generation station connecting system, method comprises shown in it is characterized in that:
Step 1: the isolated island detecting unit is with the points of common connection electric voltage feed forward;
Step 2: by preset algorithm, output current amplitude disturbance quantity;
Step 3: calculate the solar photo-voltaic power generation station output current;
Step 4: determine solar photo-voltaic power generation station whether with the bus grid cut-off.
The present invention has realized that the harmonic wave of grid-connected photovoltaic system combining inverter suppresses and isolated island detects.
Description of drawings
Fig. 1 is thin film solar photo-voltaic power generation station connecting system structure chart.
Embodiment
Below in conjunction with accompanying drawing, preferred embodiment is elaborated.Should be emphasized that, following explanation only is exemplary, rather than in order to limit the scope of the invention and to use.
Fig. 1 is thin film solar photo-voltaic power generation station connecting system structure chart.Among Fig. 1, the thin film solar photo-voltaic power generation station connecting system that the present invention proposes comprises voltage parallel mode filter and isolated island detecting unit.
The voltage parallel mode filter is connected in series between solar photo-voltaic power generation station and the combining inverter, is used for suppressing the harmonic wave that combining inverter produces.The voltage parallel mode filter is comprised of the instruction current computing module that is linked in sequence and offset current generation module.The instruction current computing module is for detection of the harmonic wave in the target compensation electric current and reactive power, and the command signal of generation offset current.Offset current generation module produces actual offset current for the command signal of the offset current that draws according to the instruction current computing module.
The isolated island detecting unit is connected in series between solar photo-voltaic power generation station and the bus, is used for the output current of monitoring solar photo-voltaic power generation station, thus determine solar photo-voltaic power generation station whether with the bus grid cut-off.
In municipal power supply system; in recent years because the extensive application of power semiconductor; make electric power system be subject to very large pollution; especially the various convertor equipments that move in electric power system easily produce a large amount of harmonic waves; one of pollutant sources of electric power system maximum; it has influence on the quality of supply of electric power; other precision equipment produces harmful effect or increases transformer in the system to being connected to; the power loss of the equipment such as electric rotating machine and power line; even cause the misoperation of protection equipment; and cause very large loss, even interfere with the normal operation of communication system and computer system.With the day by day increase of work commercial power, harmonic pollution is serious increasingly, so the research of harmonic problem is also just more important and urgent.
Photovoltaic generating system converts solar energy into direct current energy by photovoltaic module, by the grid type inverter direct current energy is converted into and electrical network same frequency, synchronous sine-wave current again, be connected to the grid, direct current energy is converted in the process of AC energy through inversion, can produce a large amount of harmonic waves.
When photovoltaic generation is operated in the low-power district, have larger current harmonics.For existing combining inverter, the effective solution that harmonic wave suppresses has team control technology and comprehensive compensation to control two kinds.
The team control technology refers in order to make inverter be operated in efficient district, with many inverter parallels, coordinates a kind of mode of controlling between inverter.Because the DC side parallel of each inverter during team control, improved the capacity of DC side, low power state with respect to non-team control, by coordinating to control so that only have 1 inverter work at this moment, this inverter work higher efficiency area can be made, thereby inverter generated output, reduction harmonic content can be improved.
Compensating Control then is integrated alternating current filter in inverter, is mainly Active Power Filter Technology, by Comprehensive Control, realize output meritorious/when Reactive Power Control, offset the harmonic component that produces.
Because film photovoltaic power station connecting system is directly given electrical network with solar energy inversion rear feed, so must there be various perfect methods to be protected.When working for system, cooperate software detection, judgement, identify and process that power device overcurrent, the power device that may occur drive that signal is under-voltage, power device is overheated, solar cell array output is under-voltage and electrical network overvoltage, the malfunction such as under-voltage by hardware circuit than being easier to.But for grid-connected photovoltaic system, also need to consider the counte-rplan under a kind of special malfunction, namely island effect prevents and countermeasure.
Island effect refers to: the power supply when Utilities Electric Co., barrier accident or when having a power failure maintenance and escape for some reason, the solar grid-connected electricity generation system of each user side is failed immediately to detect power down mode and will self be cut off the civil power networking, and the self-energizing isolated island that the Utilities Electric Co. that formation is formed by solar grid-connected electricity generation system and load on every side can't grasp.
When island effect occurs when, voltage and frequency in the uncontrollable isolated island of electrical network.If voltage and frequency exceed the scope of permission, may cause damage to user's equipment, reduced the fail safe of electrical network; If load capacity is greater than the total capacity of photovoltaic system, the photovoltaic system overlond running easily burns it; Circuit breaker reset and automatic reclosing can make main system and isolated island step-out.This shows.The generation of isolated island can cause serious consequence, so behind grid power blackout, suspension system prevents the generation of island effect to the power supply of electrical network at once.
The key of hence one can see that anti-island effect is the detection of grid cut-off, and detection time, more fugitive fruit was better.Two kinds of detection methods are generally arranged, passive detection method and active detecting method.The passive detection method is frequency and the phase place of real-time detection of grid voltage, unusually judges whether dead electricity of electrical network by frequency and phase place.Adopt passive island detection method to be not enough in the situation that load matched effectively detects the isolated island phenomenon, for this reason, must adopt active detection method.The active detecting method is by in real time electrical network parameter being sent interference signal, judges whether dead electricity of electrical network by detecting feedback signal.Can adopt active frequency drift method, sliding formwork frequency deviation method and power output Disturbance Detection method etc. detects, but certain blind area is arranged.
A kind of new island detection method is proposed here---electric voltage feed forward positive feedback disturbance island detection method.Concrete grammar is with the points of common connection electric voltage feed forward, and through certain preset algorithm, output variable is as the current amplitude disturbance quantity.Use the improvement algorithm to draw PV system (photovoltaic generating system) output current, the validity of extracting method in order to verify, all situations that may occur after need to occuring isolated island be analyzed.The method is by introducing positive feedback, make point of common coupling voltage be tending towards unstable, and adding disturbance quantity, broken the state that may occur the balance of voltage after isolated island occurs, quick isolated island when having realized separate unit or many PV grid-connected system operations detects, and has eliminated the detection blind area that exists in traditional island detection method.The method realizes simple, and is little on quality of power supply impact, has stronger engineering using value.
The objective of the invention is to study the photovoltaic plant microgrid and concentrate the distribution of access high pressure, on electrical network and load impact and countermeasure.Inquire into the method for technical solution difficult point.The generated power forecasting technology of photovoltaic plant has been proposed, networking technology etc.
Solve the actual new method of engineering of harmonic problem, in order to eliminate these harmonic waves, the passive type filter that the past adopts capacitor and inductor to form usually comes harmonic carcellation that a lot of shortcomings are arranged according to the passive type filter, own non-good solution.The filter of selecting reasonably to be incorporated into the power networks in the access way design of converters is one of reasonable mode of improving harmonic wave, and this engineering uses novel capable of dynamic to suppress the voltage parallel mode filter of harmonic wave.Wherein system is comprised of the two large divisions, i.e. instruction current computing module and offset current generation module (being made of current tracking control module, driver module and three parts of main circuit).Wherein, the core of instruction current computing module is to detect the current components such as harmonic wave in the target compensation electric current and reactive power, is harmonic wave and Detecting Reactive Current module.The effect of offset current generation module is the command signal of the offset current that draws according to the instruction current computing module, produces actual offset current.Main circuit all adopts the PWM current transformer at present.
The invention allows for a kind of island detection method---the electric voltage feed forward disturbance island detection method.Concrete grammar is with the points of common connection electric voltage feed forward, and through certain preset algorithm, output variable is as the current amplitude disturbance quantity.Use the improvement algorithm to draw PV system output current, the validity of extracting method in order to verify, all situations that may occur after need to occuring isolated island be analyzed.The method is by introducing positive feedback, make point of common coupling voltage be tending towards unstable, and adding disturbance quantity, broken the state that may occur the balance of voltage after isolated island occurs, quick isolated island when having realized separate unit or many PV grid-connected system operations detects, and has eliminated the detection blind area that exists in traditional island detection method.The method realizes simple, and is little on quality of power supply impact, and certain using value is arranged in this engineering.
In this engineering is used, find using active frequency drift method, in the time of the main criterions such as sliding formwork frequency deviation method and power output Disturbance Detection method, need the applicable condition of these main criterions of consideration, increase necessary barring condition.Take power output Disturbance Detection method as example, when little electrical network internal fault, power output Disturbance Detection method criterion also can start.In order to prevent malfunction, this device has increased the direction locking condition of inlet wire current, when namely the fault current direction is pointed to little electrical network inside, thinks little electrical network internal fault has occured, and this moment is the locking of isolated island detection criteria.
The above; only for the better embodiment of the present invention, but protection scope of the present invention is not limited to this, anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.
Claims (2)
1. a thin film solar photo-voltaic power generation station connecting system is characterized in that described system comprises voltage parallel mode filter and isolated island detecting unit;
Described voltage parallel mode filter is connected in series between solar photo-voltaic power generation station and the combining inverter, is used for suppressing the harmonic wave that combining inverter produces; Described voltage parallel mode filter is comprised of the instruction current computing module that is linked in sequence and offset current generation module; Described instruction current computing module is for detection of the harmonic wave in the target compensation electric current and reactive power, and the command signal of generation offset current; Offset current generation module produces actual offset current for the command signal of the offset current that draws according to the instruction current computing module;
Described isolated island detecting unit is connected in series between solar photo-voltaic power generation station and the bus, is used for the output current of monitoring solar photo-voltaic power generation station, thus determine solar photo-voltaic power generation station whether with the bus grid cut-off.
2. the isolated island monitoring method of a thin film solar photo-voltaic power generation station connecting system, method comprises shown in it is characterized in that:
Step 1: the isolated island detecting unit is with the points of common connection electric voltage feed forward;
Step 2: by preset algorithm, output current amplitude disturbance quantity;
Step 3: calculate the solar photo-voltaic power generation station output current;
Step 4: determine solar photo-voltaic power generation station whether with the bus grid cut-off.
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Cited By (6)
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| CN103336205A (en) * | 2013-06-27 | 2013-10-02 | 新疆希望电子有限公司 | Island effect detection system and method during simultaneous injection of two harmonic current |
| CN103368136A (en) * | 2013-07-15 | 2013-10-23 | 国家电网公司 | Method and device for processing power grid power loss |
| CN104767220A (en) * | 2015-04-14 | 2015-07-08 | 扬州大学 | Feed-forward control method for grid-connected operation mode and independent operation mode switching |
| CN105723584A (en) * | 2013-08-23 | 2016-06-29 | Abb技术有限公司 | Method and apparatus for operating a converter in a converter-based power distribution system, and power distribution system having a plurality of converter-based power transmission units |
| CN106771860A (en) * | 2016-12-07 | 2017-05-31 | 中国人民解放军后勤工程学院 | A kind of current feed-forward disturbance island detection method |
| CN110601656A (en) * | 2019-07-31 | 2019-12-20 | 成都三六八建设工程有限公司 | Photovoltaic power generation fault monitoring system and method thereof |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103336205A (en) * | 2013-06-27 | 2013-10-02 | 新疆希望电子有限公司 | Island effect detection system and method during simultaneous injection of two harmonic current |
| CN103368136A (en) * | 2013-07-15 | 2013-10-23 | 国家电网公司 | Method and device for processing power grid power loss |
| CN105723584A (en) * | 2013-08-23 | 2016-06-29 | Abb技术有限公司 | Method and apparatus for operating a converter in a converter-based power distribution system, and power distribution system having a plurality of converter-based power transmission units |
| CN105723584B (en) * | 2013-08-23 | 2018-06-05 | Abb瑞士股份有限公司 | The method and apparatus and distribution system of converter are run in a power distribution system |
| CN104767220A (en) * | 2015-04-14 | 2015-07-08 | 扬州大学 | Feed-forward control method for grid-connected operation mode and independent operation mode switching |
| CN106771860A (en) * | 2016-12-07 | 2017-05-31 | 中国人民解放军后勤工程学院 | A kind of current feed-forward disturbance island detection method |
| CN110601656A (en) * | 2019-07-31 | 2019-12-20 | 成都三六八建设工程有限公司 | Photovoltaic power generation fault monitoring system and method thereof |
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Application publication date: 20130424 |