CN102170112A - Three-phase photovoltaic inverter anti-islanding method based on phase angle deviation positive feedback - Google Patents
Three-phase photovoltaic inverter anti-islanding method based on phase angle deviation positive feedback Download PDFInfo
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- CN102170112A CN102170112A CN2011100797710A CN201110079771A CN102170112A CN 102170112 A CN102170112 A CN 102170112A CN 2011100797710 A CN2011100797710 A CN 2011100797710A CN 201110079771 A CN201110079771 A CN 201110079771A CN 102170112 A CN102170112 A CN 102170112A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
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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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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention relates to a three-phase photovoltaic inverter anti-islanding method based on phase angle deviation positive feedback, which comprises the steps as follows: carrying out disturbance to a power grid phase with T being used as a cycle, a disturbance phase angle for each time is delta theta under a grid synchronization condition of the inverter; and beginning to accumulate when a power grid voltage phase angle is 0 degree and assuming total accumulating n times within T, namely a current phase leading voltage is n*delta theta degrees, and calculating an error value delta f of the current frequency and the last periodic frequency of the power grid voltage, so that the error value is adopted as phase angle deviation positive feedback quantity. When islanding happens, the frequency of the current voltage is more than that of the last period, the delta f is positive, a control loop leads the plosive value into the positive feedback, the disturbance quantity is changed into n*delta theta+delta f at the moment, and equivalently, the forward disturbance is increased, so that the more the phase disturbance is, the more the voltage frequency deviation is, so as to form a forward deviation positive feedback system; and the system reports an overfrequency error until the frequency exceeds standard, so as to achieve the islanding protection purpose.
Description
Technical field
The present invention relates to a kind of anti-isolated island method, the anti-isolated island method of especially a kind of three-phase photovoltaic DC-to-AC converter based on the phase angle shift positive feedback.
Background technology
The electricity generation system of forming with new forms of energy is representative with wind-force, solar grid-connected generating at present; Because initial electric energy is stablized inadequately, general adopt is converted into stable direct current by power electronic technology more, obtains the also net mode of synchronous AC again via inverter.If certain bar line failure in the electric power system distribution, then can rely on nearest protective relaying device to remove, if exist the parallel net type electricity generation system in this distribution, then distributed power source can continue to powering with the distribution of electrical network disconnection, under some special situations, form independently small power generation system, this kind phenomenon is " island effect ", islet operation can be given electrical network, the user, personal safety is brought very big harm, mainly show as: under the situation of electrical breakdown, generating equipment still as isolating power supply to this phenomenon of electric, has brought great potential safety hazard for the line maintenance personnel; Do not have the support of big electrical network, the quality of power supply of distributed power source can not get guaranteeing.
The anti-isolated island method great majority of photovoltaic DC-to-AC converter adopt frequency disturbance to add passive detection method at present, there is the unsteadiness shortcoming in this type of anti-island detection method: when there is anti-isolated island failure in inversion output in different capacity section (10%～100%) when isolated island occurring, to electrical network maintenance personal security presence hidden danger; Disturbance under normal circumstances is excessive, frequent excessively, influences the inverter current harmonic wave, influences power factor of electric network.
Summary of the invention
The purpose of this invention is to provide the anti-isolated island method of a kind of phase angle shift positive feedback, suit, to the not influence of electric network performance index at the anti-isolated island of different capacity section.
For achieving the above object, the present invention is achieved through the following technical solutions:
The anti-isolated island method of a kind of three-phase photovoltaic DC-to-AC converter based on the phase angle shift positive feedback under inverter is incorporated into the power networks condition, is the cycle electrical network phase place to be carried out disturbance with the time T, and each disturbance phase angle is Δ θ; At the line voltage phase angle is 0 to begin to add up when spending, suppose to add up n time altogether in the time T, also be current phase leading voltage n* Δ θ degree, calculate the error amount Δ f of current frequency of line voltage and last period frequency simultaneously, with this error amount as the phase angle shift amount of positive feedback.
Further, Δ is carried out amplitude limit, prevent the misoperation that electrical network saltus step and interference cause.
The anti-isolated island method of three-phase photovoltaic DC-to-AC converter based on the phase angle shift positive feedback of the present invention, when isolated island took place, current electric voltage frequency was greater than last period frequency; Δ f is for just; on the occasion of introducing positive feedback, this moment, disturbance quantity became n* Δ θ+Δ f to control ring with this, was equivalent to and strengthened the forward disturbance; phase perturbation is increasing; the electric voltage frequency skew is also increasing, has formed the forward migration positive feedback system, exceeds standard up to frequency; system's newspaper overfrequency mistake reaches the purpose that isolated island is protected.
Description of drawings
According to embodiment and accompanying drawing the present invention is described in further detail below.
Fig. 1 is the anti-isolated island method of the three-phase photovoltaic DC-to-AC converter positive feedback system control block diagram based on the phase angle shift positive feedback of the present invention.
Embodiment
The anti-isolated island method of three-phase photovoltaic DC-to-AC converter based on the phase angle shift positive feedback of the present invention, under inverter is incorporated into the power networks condition, with the time T is the cycle electrical network phase place to be carried out disturbance, each disturbance phase angle is Δ θ, at the line voltage phase angle is 0 to begin to add up when spending, suppose to add up n time altogether in the time T, and also be current phase leading voltage n* Δ θ degree, calculate the error amount Δ f of current frequency of line voltage and last period frequency simultaneously, with this error amount as the phase angle shift amount of positive feedback.
Positive feedback system control block diagram as shown in Figure 1.
When not having isolated island, electric network voltage phase is determined by electrical network, Δ f=0, and amount of positive feedback is 0.The three-phase current phase place keeps synchronously with voltage all the time, and promptly inverter power factor PF value is greater than 0.99.
When isolated island takes place; current electric voltage frequency is greater than last period frequency, and Δ f is being for just, control ring with this on the occasion of introducing positive feedback; this moment, disturbance quantity became n* Δ θ+Δ f; be equivalent to and strengthen the forward disturbance, phase perturbation is increasing, and the electric voltage frequency skew is also increasing; formed the forward migration positive feedback system; exceed standard up to frequency, system's newspaper overfrequency mistake reaches the purpose that isolated island is protected.Simultaneously Δ f is carried out amplitude limit, prevent the misoperation that electrical network saltus step and interference cause.
Adopt the method for the invention, its test result is: isolated island begins to have the reliability height, the characteristics that rapidity is good to 135ms inverter protection (requiring in the 2S).The method is applicable to the three-phase photovoltaic DC-to-AC converter, can avoid anti-isolated island inefficacy under the different capacity grade, has accurately quick anti-isolated island ability; The electrical network saltus step can not cause the isolated island erroneous judgement, to electric network performance index (THD, PF) not influence of value.
Claims (2)
1. anti-isolated island method of the three-phase photovoltaic DC-to-AC converter based on the phase angle shift positive feedback is characterized in that:
Under inverter is incorporated into the power networks condition, be the cycle electrical network phase place to be carried out disturbance with the time T, each disturbance phase angle is Δ θ; At the line voltage phase angle is 0 to begin to add up when spending, suppose to add up n time altogether in the time T, also be current phase leading voltage n* Δ θ degree, calculate the error amount Δ f of current frequency of line voltage and last period frequency simultaneously, with this error amount as the phase angle shift amount of positive feedback.
2. the anti-isolated island method of the three-phase photovoltaic DC-to-AC converter based on the phase angle shift positive feedback according to claim 1 is characterized in that: Δ f is carried out amplitude limit, prevent the misoperation that electrical network saltus step and interference cause.
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| CN2011100797710A CN102170112A (en) | 2011-03-31 | 2011-03-31 | Three-phase photovoltaic inverter anti-islanding method based on phase angle deviation positive feedback |
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| CN2011100797710A CN102170112A (en) | 2011-03-31 | 2011-03-31 | Three-phase photovoltaic inverter anti-islanding method based on phase angle deviation positive feedback |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102608496A (en) * | 2012-03-15 | 2012-07-25 | 北京昆兰新能源技术有限公司 | Improved type positive feedback active frequency deviation island detection method |
| CN102611137A (en) * | 2012-03-16 | 2012-07-25 | 北京昆兰新能源技术有限公司 | Three-phase photovoltaic inverter active anti-island method based on reactive power disturbance |
| CN103138268A (en) * | 2013-02-25 | 2013-06-05 | 国家电网公司 | Low-voltage anti-island device of distributed photovoltaic power generation systems |
| CN103901295A (en) * | 2014-02-21 | 2014-07-02 | 江苏兆伏新能源有限公司 | Single-phase and two-phase islanding detection method based on power grid negative sequence |
| WO2021098595A1 (en) * | 2019-11-22 | 2021-05-27 | 科华恒盛股份有限公司 | Islanding disturbance method and system, and terminal device |
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| CN101123349A (en) * | 2007-07-20 | 2008-02-13 | 东南大学 | Island effect detection method based on active frequency deviation and its device |
| CN102183733A (en) * | 2011-03-07 | 2011-09-14 | 河海大学 | Photovoltaic grid connected inverter island detection method for improving quality of electric energy |
| CN102262182A (en) * | 2011-07-07 | 2011-11-30 | 浙江大学 | Method for detecting island of photovoltaic grid-connected inverter |
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2011
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| CN101123349A (en) * | 2007-07-20 | 2008-02-13 | 东南大学 | Island effect detection method based on active frequency deviation and its device |
| CN102183733A (en) * | 2011-03-07 | 2011-09-14 | 河海大学 | Photovoltaic grid connected inverter island detection method for improving quality of electric energy |
| CN102262182A (en) * | 2011-07-07 | 2011-11-30 | 浙江大学 | Method for detecting island of photovoltaic grid-connected inverter |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102608496A (en) * | 2012-03-15 | 2012-07-25 | 北京昆兰新能源技术有限公司 | Improved type positive feedback active frequency deviation island detection method |
| CN102611137A (en) * | 2012-03-16 | 2012-07-25 | 北京昆兰新能源技术有限公司 | Three-phase photovoltaic inverter active anti-island method based on reactive power disturbance |
| CN102611137B (en) * | 2012-03-16 | 2014-11-26 | 北京昆兰新能源技术有限公司 | Three-phase photovoltaic inverter active anti-island method based on reactive power disturbance |
| CN103138268A (en) * | 2013-02-25 | 2013-06-05 | 国家电网公司 | Low-voltage anti-island device of distributed photovoltaic power generation systems |
| CN103901295A (en) * | 2014-02-21 | 2014-07-02 | 江苏兆伏新能源有限公司 | Single-phase and two-phase islanding detection method based on power grid negative sequence |
| WO2021098595A1 (en) * | 2019-11-22 | 2021-05-27 | 科华恒盛股份有限公司 | Islanding disturbance method and system, and terminal device |
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Application publication date: 20110831 |