CN103606907A - An anti-islanding detection method - Google Patents
An anti-islanding detection method Download PDFInfo
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- CN103606907A CN103606907A CN201310573942.4A CN201310573942A CN103606907A CN 103606907 A CN103606907 A CN 103606907A CN 201310573942 A CN201310573942 A CN 201310573942A CN 103606907 A CN103606907 A CN 103606907A
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Abstract
The invention relates to an anti-islanding detection method comprising the following steps: a control system outputs reactive power output disturbance instructions to a three-phase inverter, and whether an islanding phenomenon exists is determined through detecting whether a time difference due to phase difference of any two phases of a three-phase voltage exceeds an allowed threshold; if the time difference exceeds the threshold, the islanding phenomenon occurs to the three-phase inverter; instructions formed by the time difference is returned to the three-phase inverter as feedbacks and the reactive power disturbance instructions are changed, so that the three-phase inverter breaks off and active anti-islanding is realized. According to the invention, whether the islanding phenomenon exists is determined through detecting whether the time difference due to phase difference of any two phases of the three-phase voltage exceeds the allowed threshold, and a feedback mechanism is formed through reactive disturbances, so that a purpose of controlling the turn-on and turn-off of the inverter is realized, and the inverter can normally determines the islanding phenomenon which occurs and carries out islanding protection in conditions of single-phase or two-phase islanding.
Description
Technical field
The present invention relates to a kind of combining inverter that is applicable to detect and to prevent it that method of isolated island phenomenon occurs.
Background technology
In photovoltaic parallel in system, as shown in Figure 1, Blast Furnace Top Gas Recovery Turbine Unit (TRT) accesses in electrical network by inverter, and can connect local load.When grid-connected inverter is thrown off electrical network, can there is isolated island phenomenon, now need at the appointed time interior disconnection of inverter, this is anti-isolated island method.Due to the local load that may exist on inverter, so various countries' safety only requires inverter also can spill isolated island phenomenon timely off-grid for local resonant load.
In existing technology, anti-isolated island is mainly divided into passive anti-isolated island and the anti-isolated island function of active.Passive anti-isolated island refers to that system is when occurring isolated island phenomenon, according to there will be electrical network overvoltage, under-voltage, overfrequency, and the phenomenons such as under-frequency judge.This method can only cover part isolated island phenomenon, substantially approaches in the situation of inverter power normally off-grid for local load.At this time just need initiatively anti-isolated island method to realize.
Initiatively anti-isolated island method mainly contains by electric network impedance measurement, phase hit, frequency disturbance, meritorious disturbance and idle disturbance etc. and realizes.Wherein the algorithm of electric network impedance method of measurement is complicated, realizes difficulty.Phase hit method cannot all isolated island situations of fine covering, and easily erroneous judgement.Meritorious disturbance is not too favourable for there being magnetic field to close, and can cause electrical network less stable.So main application is frequency disturbance method and idle perturbation motion method.
Frequency disturbance side's ratio juris is not changed in non-isolated island situation based on mains frequency.System is controlled the frequency instruction and the actual electric network that provide and is had droop, and in non-isolated island situation, this droop does not affect the frequency of output grid-connected current.Only have when isolated island occurs, inverter frequency changes with output frequency, and phase-locked loop (PLL) is followed the tracks of output frequency and phase angle simultaneously, adjusts output frequency to a direction simultaneously, forms positive feedback mechanism.Make within a certain period of time frequency go beyond the scope, reach protection object.
Idle perturbation motion method and frequency disturbance mechanism are similar; but what use is the method for disturbance reactive power; make to export the output frequency that certain idle disturbance changes isolated island in the situation that of inverter generation isolated island; by adjusting the instruction of output reactive power; form positive feedback mechanism, realize the object of anti-island protect.
For three phase network system, due to the anti-isolated island technology of current major part, as above-mentioned each side method is all considered the situation that three-phase disconnects simultaneously.During as IEC62116 standard testing, only test the protection under three-phase isolated island phenomenon; and VDE0126-1-1 standard also will be examined or check the protection mechanism under single-phase isolated island wherein to three-phase system simultaneously, make current most of anti-isolated island mechanism adopting complete failure in this case.Because the in the situation that of a phase or two-phase isolated island, three-phase inversion control system based on vector control method, three-phase frequency now is also limited by mains frequency, and inverter output cannot change the frequency of output current and voltage, and the method based on frequency positive feedback was now all lost efficacy.And can be effective based on independent single-phase electric network impedance measurement and the perturbation motion method of gaining merit, but having its shortcoming: the former realizes complexity, and the meritorious disturbance of the latter is more unfavorable to grid stability, and the latter also can affect MPPT algorithm sometimes.
Summary of the invention
The simple and effective anti-island detection method that the object of this invention is to provide a kind of isolated island phenomenon for a phase or two-phase and propose.
For achieving the above object, the technical solution used in the present invention is:
A kind of anti-island detection method, for detection of being connected between Blast Furnace Top Gas Recovery Turbine Unit (TRT) and electrical network and whether the three-phase inverter of working under the control of control system occurs isolated island phenomenon and carry out the anti-isolated island of active, the method comprises: described control system is to the defeated idle disturbance instruction that goes out of described three-phase inverter, detect in the three-phase voltage of described three-phase inverter output arbitrarily between two-phase owing to differing the time difference causing and whether exceed allowed threshold value and judge whether to occur isolated island phenomenon, if the described time difference surpasses described threshold value, three-phase inverter generation isolated island phenomenon, described time difference formation instruction feedback changes described idle disturbance instruction to described three-phase inverter, by changing described idle disturbance instruction, make described three-phase inverter disconnection realize initiatively anti-isolated island.
In said method, if a certain time difference respectively and between all the other two-phases mutually in the three-phase voltage of described three-phase inverter output surpasses described threshold value, there is isolated island phenomenon in this mutually.
Because technique scheme is used; the present invention compared with prior art has following advantages: in the three-phase voltage of the present invention by the output of detection three-phase inverter, judge isolated island phenomenon arbitrarily between two-phase owing to differing the time difference causing; and form feedback mechanism by idle disturbance; reach the object that control inverter disconnects, make inverter in the situation that of single-phase or two-phase isolated island, can normally judge the isolated island phenomenon of generation and to make island protect.
Accompanying drawing explanation
The schematic diagram that accompanying drawing 1 is photovoltaic parallel in system.
The schematic flow sheet that accompanying drawing 2 is anti-island detection method of the present invention.
Accompanying drawing 3 is the schematic vector diagram of three-phase current and three-phase voltage in anti-island detection method of the present invention.
Embodiment
Below in conjunction with embodiment shown in the drawings, the invention will be further described.
Embodiment mono-: a kind of anti-island detection method, and for detection of being connected between Blast Furnace Top Gas Recovery Turbine Unit (TRT) and electrical network and whether the three-phase inverter of working under the control of control system occurs isolated island phenomenon and carry out the anti-isolated island of active.
As shown in Figure 3, anti-isolated island method of the present invention is based on three-phase inverter and control system thereof.Three-phase inverter output three-phase equilibrium electric current is respectively Ia, Ib, Ic, forms 120 ° of angles and amplitude identical between three-phase current.In non-isolated island situation, three-phase voltage is respectively as shown in Ua, Ub, Uc in accompanying drawing 3, and also amplitude is identical and be each other 120 degree angles.For example, and when certain phase, when isolated island phenomenon occurs A mutually, its voltage changes Ua ' into.Show after deliberation, differing between three-phase voltage is relevant to the idle disturbance of three-phase transformer input with control system, and this to differ be the dimension based on absolute time, when there is isolated island phenomenon, the time dimension that this differs can change thereupon.Therefore, the variation that differs brought time dimension by detection can reach the object that isolated island detects, and can form positive feedback by it and change idle disturbance, thereby realizes island protect.
Therefore a kind of anti-island detection method, comprise: control system to be to the defeated idle disturbance instruction that goes out of three-phase inverter, detect in the three-phase voltage of three-phase inverter output arbitrarily between two-phase owing to differing the time difference causing and whether exceed allowed threshold value and judge whether to occur isolated island phenomenon.If the time difference surpasses threshold value, three-phase inverter generation isolated island phenomenon, if a certain time difference respectively and between all the other two-phases mutually in the three-phase voltage of three-phase inverter output surpasses threshold value, there is isolated island phenomenon in this mutually.Time difference forms instruction feedback and changes idle disturbance instruction to three-phase inverter, by changing idle disturbance instruction, makes three-phase inverter disconnection realize initiatively anti-isolated island.
Specifically, as shown in accompanying drawing 2 and accompanying drawing 3, under normal circumstances, the three-phase current of three-phase transformer output is Ia, Ib, Ic, and the three-phase voltage of output is Ua, Ub, Uc.Between the electric current I a of A phase and voltage U a, shape has a certain degree, and differs.Suppose the A phase voltage generation isolated island phenomenon of three-phase transformer output, its voltage changes Ua ' into by Ua, now, Ua is nearer apart from the voltage U b of other two-phases or the distance of Uc, and differing changes changes A phase and the time difference Δ T between B phase or A phase and C phase.A given idle disturbance Iq, detects owing to differing brought time difference Δ T and whether has surpassed admissible threshold value and can judge A whether isolated island phenomenon occurs mutually.This threshold value can draw according to the related data of three-phase inverter and electrical network, if time difference Δ T has surpassed this threshold value, can conclude that isolated island phenomenon has occurred A mutually.Now; by detecting the information about time difference Δ T obtaining, change instruction feedback in the control system of three-phase inverter; make control system change the idle disturbance Iq providing to three-phase inverter; thereby the idle disturbance of inputting three-phase inverter by change disconnects it, reaches the object of island protect.
Above-mentioned anti-island detection method has solved a certain problem that occurs isolated island phenomenon and cannot detect and prevent in three-phase system, meets IEC62116 and VDE0126-1-1 about the demand of the anti-isolated island of photovoltaic DC-to-AC converter aspect.
Above-described embodiment is only explanation technical conceive of the present invention and feature, and its object is to allow person skilled in the art can understand content of the present invention and implement according to this, can not limit the scope of the invention with this.All equivalences that Spirit Essence is done according to the present invention change or modify, within all should being encompassed in protection scope of the present invention.
Claims (2)
1. an anti-island detection method, for detection of being connected between Blast Furnace Top Gas Recovery Turbine Unit (TRT) and electrical network and whether the three-phase inverter of working under the control of control system occurs isolated island phenomenon and carry out the anti-isolated island of active, it is characterized in that: the method comprises: described control system is exported idle disturbance instruction to described three-phase inverter, detect in the three-phase voltage of described three-phase inverter output arbitrarily between two-phase owing to differing the time difference causing and whether exceed allowed threshold value and judge whether to occur isolated island phenomenon, if the described time difference surpasses described threshold value, three-phase inverter generation isolated island phenomenon, described time difference formation instruction feedback changes described idle disturbance instruction to described three-phase inverter, by changing described idle disturbance instruction, make described three-phase inverter disconnection realize initiatively anti-isolated island.
2. anti-island detection method according to claim 1, is characterized in that: if a certain time difference respectively and between all the other two-phases mutually in the three-phase voltage of described three-phase inverter output surpasses described threshold value, isolated island phenomenon occurs mutually for this.
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Cited By (4)
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| CN104659758A (en) * | 2015-01-26 | 2015-05-27 | 国网浙江海盐县供电公司 | Anti-islanding grid-connection switch protection method for distributed type power supply system and grid-connection switch device |
| CN105629087A (en) * | 2014-10-17 | 2016-06-01 | 国家电网公司 | Improved inverter anti-island detection method |
| CN117805541A (en) * | 2024-02-29 | 2024-04-02 | 西安千帆翼数字能源技术有限公司 | Island detection method, protection method and related device of energy storage converter |
| CN117805541B (en) * | 2024-02-29 | 2024-05-03 | 西安千帆翼数字能源技术有限公司 | Island detection method, protection method and related device of energy storage converter |
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| US20130187473A1 (en) * | 2012-01-24 | 2013-07-25 | Infineon Technologies Austria Ag | Power Converter Circuit |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105629087A (en) * | 2014-10-17 | 2016-06-01 | 国家电网公司 | Improved inverter anti-island detection method |
| CN105629087B (en) * | 2014-10-17 | 2018-10-26 | 国家电网公司 | A kind of anti-island detection method of improved inverter |
| CN104659758A (en) * | 2015-01-26 | 2015-05-27 | 国网浙江海盐县供电公司 | Anti-islanding grid-connection switch protection method for distributed type power supply system and grid-connection switch device |
| CN117805541A (en) * | 2024-02-29 | 2024-04-02 | 西安千帆翼数字能源技术有限公司 | Island detection method, protection method and related device of energy storage converter |
| CN117805541B (en) * | 2024-02-29 | 2024-05-03 | 西安千帆翼数字能源技术有限公司 | Island detection method, protection method and related device of energy storage converter |
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Application publication date: 20140226 |