CN105182189B - The inverter combined based on electric voltage frequency and measurement impedance disturbs formula isolated island detection method - Google Patents
The inverter combined based on electric voltage frequency and measurement impedance disturbs formula isolated island detection method Download PDFInfo
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Abstract
The present invention relates to Power System Analysis technical field, and formula isolated island detection method is disturbed more particularly to a kind of inverter combined based on electric voltage frequency and measurement impedance, it is characterised in that：The idle relation of frequency after analysis isolated island first；Control sets the idle feedback transmitter inverter of frequency, adds a feedback factor；If the reactive power sum of each inverter output is not zero, then according to the electric voltage frequency of combining inverter beyond whether the limitation of normal operation detects whether island operation state occur, otherwise using one voltage source signal of concentration injection at system point of common coupling, the signal is single-frequency signals, injection mode is injected for three-phase, detects whether island operation state occur by the feature difference of the systematic survey impedance at system point of common coupling.Isolated island detection method proposed by the present invention can avoid more disturbing signal mutual interference failures under multiple inverter system scene, have higher reliability；With higher detection speed；Principle is easy and effective.
Description
Technical field
The present invention relates to Power System Analysis technical field, more particularly to one kind based on electric voltage frequency and measurement impedance knot
The inverter disturbance formula isolated island detection method of conjunction.
Background technology
Worldwide, conventional fossil energy is increasingly exhausted, while problem of environmental pollution increasingly causes the concern of people,
Therefore, national governments increasingly pay attention to the development of regenerative resource.Photovoltaic system distributed power supply more and more match somebody with somebody by access
Power network, with incrementally increasing for distributed power source capacity, the radiant type network of distribution system from a power one-way flow is changed into
The complex network of the more power supplys and Power System Interconnection of one power energy two-way flow.Thus there is the grid-connected protection of distributed power generation
Problem, isolated island protection is exactly one of them.
The islet operation of distributed photovoltaic system refers to power network due to originals such as electric fault, artificial origin or natural causes
During because of interruption of power supply, photovoltaic system fails to detect power down mode and departs from power network, continues to convey electric energy, and this to system nearby
The self-supporting power supply isolated island not controlled by public electric wire net that ground load is together formed.It is in distributed photovoltaic power generation system
During island operation state, the quality of power supply can be influenceed or even damage electrical equipment, islet operation circuit continues powered to influence failure
Arc extinction so that unsuccessful reclosing, it is serious when entail dangers to attendant personal safety.Therefore, either from secure context
Or from the aspect of reliability, unplanned island operation state does not allow, it should timely and effectively detects orphan
Island running status, and photovoltaic DC-to-AC converter is broken from system point of common coupling (Point of Common Coupling, PCC) place
Open, i.e., isolated island is protected.
Island detection method is divided into distance type method, proactive and passive type method according to operation principle again.Wherein,
Contributed after passive detection method analysis isolated island due to distributed power source and mismatch the electrical quantity for causing to protect installation place with load nearby
Change, this kind of method are realized simply, but contributed in distributed power source with check frequency be present during load approximate match nearby；Actively
Detection method is generally injected using inverter to system to be disturbed, and the front and rear response change of measuring system isolated island, detection can be reduced or eliminated
Blind area, but system power quality can be influenceed.
The main direction of studying detected at present through inverter networking distributed generator islanding is active detection method, to reduce
Or eliminate check frequency.However, with system to it is various when varying duty, the grid-connected development of multi-inverter, each inverter in active method
Disturbing signal interaction cause isolated island detection failure, it is therefore desirable to carry out for tradition based on inverter disturbance it is active
The research of the isolated island detection method of detection method Problem of Failure.
The content of the invention
In order to solve the above problems, the technical scheme that the present invention takes is as follows：
A kind of inverter combined based on electric voltage frequency and measurement impedance disturbs formula isolated island detection method, it is characterised in that institute
The method of stating comprises the following steps：
The idle relation of frequency before and after step 1, analysis isolated island；
Step 2, control set the inverter of frequency-idle feedback transmitter, and the reactive power disturbance of system chooses public coupling
Point electric voltage frequency faWith power network rated frequency fgDifference, in order that the change of less frequency obtains enough reactive disturbances to carry
High detection speed, the feedback of frequency is added in disturbance quantity, add a feedback factor k, then the idle work(of inverter output
Rate Qinv=k (fa-fg)；
If the reactive power sum ∑ Q of step 3, each inverter outputinv≠ 0, then according to the electric voltage frequency of combining inverter
Beyond the limitation of normal operation, island operation state is detected, system is not if electric voltage frequency is without departing from the limitation of normal operation
In island operation state；If the reactive power sum ∑ Q of each inverter outputinv=0, then according to the voltage of combining inverter
Frequency beyond whether normal operation limitation come detect whether to occur the detection method of island operation state fail, perform step 4；
Step 4, one voltage source signal of injection is concentrated at system point of common coupling, the signal is single-frequency signals,
Injection mode is injected for three-phase, the injecting voltage and the data of current-responsive measured at acquisition system point of common coupling, through data
After processing, measurement impedance at system point of common coupling is calculated to obtain；The impedance Z of usual power networkGirdMuch smaller than the resistance of distributed power source
Anti- ZDGWith the impedance Z of loadload,
ZGrid＜ ＜ ZDG,ZGrid＜ ＜ Zload
Before isolated island, the measurement impedance Z at system point of common couplingmeasFor：
After isolated island, measurement impedance Z at system point of common coupling 'measFor：
Z′meas=ZΙslanding＞ ＞ Zmeas
ZIslandingThe systematic survey impedance after isolated island generation is represented, is carried out based on impedance characteristic difference before and after above isolated island
Impedance measurement isolated island detects.
In the step 3, according to the electric voltage frequency of combining inverter beyond whether the limitation of normal operation detects whether
Occur island operation state detection method failure mechanism be：This method is corresponding according to the change output of system real-time frequency
Reactive power so that unbalanced due to reactive power after isolated island, the electric voltage frequency of islanded system is because positive feedback amplification is beyond just
The limitation often run, so as to detect island operation state；However, because local load is also real-time change, load changes
With randomness, if the reactive power change of the idle change locally loaded and the detection detection output of photovoltaic system isolated island is firm
Good to offset, now the detection method is failure；In addition, in multi-inverter or multi-computer cluster system, because inverter is large number of, respectively
The reactive disturbance of inverter output mutually can cut down or offset, and the detection method at this moment is also failure.
Beneficial effect
(1) the reason for analyzing and demonstrating the detection failure of active class method isolated island mechanism, to avoid isolated island detection failure
Specific aim reference is provided；
(2) because being injected using centralized specific frequency disturbing signal, this method is independent of inverter, not by power supply type office
Limit；
(3) a kind of inverter disturbance formula isolated island detection method combined based on electric voltage frequency and measurement impedance proposed is avoided that
More disturbing signal mutual interference failures, have higher reliability under multiple inverter system scene；
(4) do not need frequency departure to be gradually amplified to the process of action threshold value, there is higher detection speed；Principle is simple
Effectively.
Brief description of the drawings
Fig. 1 is the electrical block diagram of grid-connected inverter system.
Fig. 2 is the control structure figure of three-phase frequency-idle feedback isolated island detection method.
Fig. 3 is that the anti-isolated island of the present invention detects the equivalent schematic diagram of dead methods.
Fig. 4 a-4b are according to inverter exit potential frequency and output under specific embodiment of the invention normal operation
Idle oscillogram.
Fig. 5 a-5b are frequency in the case of the isolated island according to specific embodiment of the invention application three-phase frequency-idle feedback transmitter
Rate and idle oscillogram.
Fig. 6 a-6b are to detect failure conditions lower frequency and idle oscillogram according to specific embodiment of the invention isolated island.
Fig. 7 is special using the time domain on-line measurement impedance of anti-failure island detection method according to the specific embodiment of the invention
Levy Dependence Results figure.
A kind of flow charts of the inverter disturbance formula isolated island detection method combined based on electric voltage frequency and measurement impedance of Fig. 8.
Embodiment
Below in conjunction with the accompanying drawings, the present invention is elaborated.Fig. 8 it is a kind of based on electric voltage frequency and measurement impedance combine it is inverse
Become the flow chart of device disturbance formula isolated island detection method.
Judge whether photovoltaic system is in island operation state according to the amplitude of the output voltage of combining inverter and frequency.
In order to improve the benefit of photovoltaic system, general photovoltaic system only sends active power, that is, worked under unity power factor.Photovoltaic
When system is incorporated to bulk power grid, the reference voltage of inverter output end is clamped down on by bulk power grid, is rated operational voltage.For three
Equal balance system, combining inverter power output are：
In formula, PinvFor the active power of inverter output, QinvFor the reactive power of inverter output, ud、uqAnd id、iq
Voltage and current respectively under the three-phase voltage and current transformation to two-phase rotating coordinate system of the output of photovoltaic system inverter, by
Line voltage vector is oriented in the d axles of d-q coordinate systems, now there is uq=0, obtain：
When photovoltaic system is incorporated into the power networks, ud、uqIt is constant, under power limitation control strategy, photovoltaic system exports active
Power and reactive power correspond to i respectivelyd、iq.Therefore, when studying isolated island protection, combining inverter is approximately that local load is parallel connection
RLC loads and the current source that operates under unit power.The schematic circuit of grid-connected inverter system is as shown in Figure 1.
When K1, K2 are closed, inverter power supply is incorporated into the power networks, then has：
P in formulaloadFor system normal operation when the active power of load absorption, QloadInhaled to be loaded during system normal operation
The reactive power of receipts；PinvFor the active power of inverter output, QinvFor the reactive power of inverter output；Δ P is local negative
It is reactive power mismatch degree to carry and mismatch degree, the load of Δ Q locals and generating with electricity generation system active power；UgFor inverter
Output end voltage amplitude, f when being incorporated into the power networksgOutput end frequency when being run for grid-connected inverters.
After K2 trippings, local load is individually powered by combining inverter.Combining inverter works in power limitation control mould
During formula, after islet operation, the voltage U of local load endisland, local load end frequency fisland, P 'loadLoad consumption is active
Power, Q 'loadLoad consumption reactive power.Now, then have：
Local load terminal voltage U when calculating islet operation by formula (3)island, i.e.,：
Combining inverter runs on unit power condition, i.e. QinvWhen=0, after islet operation generation, inverter and power network
Neither reactive power, the frequency f of local load end when calculating islet operation according to formula (4) are provided to loadisland, i.e.,：
Therefore, local load mismatches degree Δ P and U with electricity generation system active powerislandRelation be：
Local load and generating are reactive power mismatch degree Δ Q and fislandRelation be
In formula,For the quality factor of load.
When inverter and power network disconnection, if the active-power P of inverter outputinv, inverter output reactive power
QinvMismatch with the power needed for load, be i.e. when Δ P and Δ Q are not equal to 0, released from formula (9) and (10), inverter output
Voltage and frequency will all change.After if inverter and power network disconnected, the active-power P of inverter outputinv, inversion
The reactive power Q of device outputinvWith load needed for power it is almost equal, i.e. Δ P=0, Δ Q=0, substitute into formula (9) and (10) must
To Uisland=Ug, fisland=fg.The reactive power disturbance of system chooses PCC electric voltage frequencies and the difference isolated island of power network rated frequency
After operation, PCC electric voltage frequencies are relevant with the reactive power that inverter exports, therefore are changed by disturbing the idle output of inverter
Become PCC electric voltage frequencies, judge that grid-connected inverter system whether there is islet operation with this.
Active frequency drift method (Active Frequency Drift, AFD) is one kind of active alone island detection method, single-phase frequency
The operation principle of rate deflection method is shifted by the frequency of frequency disturbance PCC voltages, due to before isolated island by bulk power grid
Clamp down on, frequency keeps 50Hz, and the adjustment effect of bulk power grid is lost after isolated island, frequency shift (FS) goes out the scope of permission, is judged with this
Isolated island, method realizes simple, isolated island discrimination height, but when local quality factor are higher, easily causes detection to fail.In three-phase
In the isolated island detection of frequency shift (FS), the reference current based on d-q conversion control methods is used as DC quantity, can not be directly by changing
The frequency and phase of variable reference electric current enter line displacement to the frequency of electric current.Now for the island detection method of three-phase frequency shift (FS)
In, more commonly used is three-phase reactive disturbance method, passes through reactive power or current disturbing so that PCC voltages after bulk power grid disconnects
Frequency shift (FS).In three-phase reactive disturbance method, there are reactive power disturbance and reactive current disturbance, respectively for power limitation control
And constant current controlling.
The reactive power disturbance of system chooses the difference of PCC electric voltage frequencies and power network rated frequency, in order that obtaining less frequency
Rate change obtains enough reactive disturbances to improve detection speed, and the feedback of frequency is added in disturbance quantity, adds one instead
Feedforward coefficient, i.e. three-phase frequency-idle feedback transmitter, its control structure figure is as shown in Fig. 2 its expression formula is as follows：
Qinv=k (fa-fg) (11)
In formula, k is frequency feedback coefficient；faFor the frequency of PCC voltages；fgFor line voltage rated frequency, 50Hz.
Use power limitation control method control photovoltaic system export active power and reactive power for definite value, photovoltaic system is simultaneously
It is rated voltage that site voltage is clamped down on by big system, at the PCC under the two-phase rotating coordinate system formed after d-q is converted
Voltage Udpcc、UqpccAnd steady state value, it follows that reference currentReference currentIntroduce two current status feedback quantity ω
LidWith ω LiqTo realize decoupling, generation reference voltage Ud, reference voltage Uq, then convert by dq-abc, generate PWM signal
Ripple, the voltage and current needed for inverter output is controlled by PWM.
After islet operation occurs, when locally load and inverter output power matching degree are higher, PCC electric voltage frequencies
Vary less, reactance or filter capacitor production are connected due to the feedback of pull-in frequency, in the reactive disturbance and inverter of load
Raw idle skew all can become big due to the effect of feedback, until frequency shift (FS) exceeds isolated island detection range, isolated island protection act.
Three-phase frequency-idle feedback transmitter is the corresponding reactive power of change output according to system real-time frequency so that lonely
Unbalanced due to reactive power behind island, the electric voltage frequency of islanded system exceeds the limitation of normal operation, so as to detect isolated island
Running status.However, because local load is also real-time change, load change has randomness, if the nothing locally loaded
Work(changes and the just counteracting of the reactive power change of photovoltaic system isolated island detection detection output, and now active detecting method is failure
's；In multi-inverter or multi-computer cluster system, because inverter is large number of, the reactive disturbance of each inverter output can mutually cut down
Or offset, i.e. ∑ Qinv=0, now active detecting method is failure.
A kind of inverter combined based on electric voltage frequency and measurement impedance disturbs formula isolated island detection method, and equivalent constructions are illustrated such as
Fig. 3, different from traditional inverter generator terminal perturbation scheme, and the concentration disturbing signal injection at PCC is used, Injection Signal is
Voltage signal, the signal are specific single-frequency, and injection mode is injected for three-phase.
The impedance Z of usual power networkGirdMuch smaller than the impedance Z of distributed power sourceDGWith the impedance Z of loadload,
ZGrid＜ ＜ ZDG,ZGrid＜ ＜ Zload (12)
Before isolated island, the measurement impedance Z at PCCmeasFor：
After isolated island, measurement impedance Z at PCC 'measFor：
Z′meas=ZΙslanding＞ ＞ Zmeas (15)
Formula (14)-(15) show, Z 'meas＞ ＞ Zmeas, impedance measurement isolated island inspection is carried out based on this impedance characteristic difference
Survey.The injecting voltage and the number of current-responsive that measurement impedance before and after isolated island at PCC is measured by acquisition system point of common coupling
According to being calculated after data processing.
Illustrate a kind of inversion combined based on electric voltage frequency and measurement impedance of the present invention with more specifical example below
Device disturbs the technique effect of formula isolated island detection method.Grid-connected inverter system circuit model as shown in Figure 1 is used in this example.Light
Volt inverter is employed and controlled shown in Fig. 2.
It is to be controlled according to formula (11) and Fig. 2 below, the simulation implementation carried out under matlab/simulink, simulation parameter：
For photovoltaic system to be incorporated to 220kV Infinite bus systems through boosting after 3 photovoltaic DC-to-AC converter parallel connections, active power output is 3*100kW,
Idle output determines by difference on the frequency, Qinv=k (fa- 50) Var, wherein feedback factor k=-3802.RLC is loaded and is connected in
10.5kV on bus：Active load Pload=300kW, Qload.L=150kVar, Qload.C=-152kVar.System is in 0.2s
Generation isolated island, emulation duration is 1.2s.Because three grid-connected photovoltaic DC-to-AC converters are fully equivalent, and PCC frequencies and inversion
Device exit frequency is identical, therefore only investigates the frequency of the voltage of No. 1 inverter output.Its simulation result is as shown in Figure 4.
The frequency of the voltage of (PCC is same) and inverse at inverter outlet when Fig. 4 show no active detecting method
Become the waveform of the reactive power of device output.Influenceed by photovoltaic system control strategy, in 0.4s or so, photovoltaic system output
Reactive power just tends towards stability, and is that from now on, system operation is in stable state.Because power and bear that inverter exports
The power match degree that lotus is consumed is higher, after bulk power grid disengaging, during photovoltaic system islet operation, photovoltaic system output
Power can be dissolved by load completely just, and system does not fluctuate substantially, being capable of normal operation.Now, when islet operation can be longer
Between continue.But it is detrimental to the personal safety of attendant and the safety of power system device.
Fig. 5 show isolated island situation lower frequency and idle oscillogram of the present invention using three-phase frequency-idle feedback transmitter.
After the three-phase frequency as shown in formula (11)-idle feedback transmitter photovoltaic isolated island inspection policies, other simulated conditions are constant, emulation
As a result it is as shown in Figure 5.The frequency of system drops down to below 49.5Hz after isolated island in 0.2s so that the isolated island fortune of photovoltaic system
Row state can be detected faster.The reactive power of photovoltaic system output rises with the decline of frequency so that frequency
Rate further declines.Detected it follows that three-phase frequency-idle feedback transmitter is the isolated island that can be suitably used for photovoltaic system.
Three-phase frequency-idle feedback transmitter is the corresponding reactive power of change output according to system real-time frequency so that lonely
Unbalanced due to reactive power behind island, the electric voltage frequency of islanded system exceeds the limitation of normal operation, so as to detect isolated island
Running status.However, because local load is also real-time change, load change has randomness, if the nothing locally loaded
Work(changes and the just counteracting of the reactive power change of photovoltaic system isolated island detection detection output, and now the detection method is failure
In multi-inverter or multi-computer cluster system, because inverter is large number of, the reactive disturbance of each inverter output can mutually cut down or
Offset, now the detection method is failure.
The emulation of failure Mechanism, simulation parameter are carried out under matlab/Simulink：Photovoltaic system is 3 photovoltaics
220kV Infinite bus systems are incorporated to through boosting after inverter parallel, active power output is 3*100kW, and idle output is by difference on the frequency
To determine, Qinv=k (fa- 50) Var, wherein feedback factor k=-3802.RLC is loaded：Active load is simultaneously connected in 10.5kV
On bus：Pload=300kW, Qload.L=150kVar, Qload.C=-152kVar.Isolated island occurs in 0.2s for system, during emulation
Length is 1.2s.In order to simulate the real-time change of local load reactive power, set the idle value of feedback of one of photovoltaic system
It is set to two other idle value of feedback and obtains negative sum, i.e.,：Qinv.3=-2*k (fa-50)Var.PCC frequencies and inverter outlet
Locate that frequency is identical, therefore investigate the frequency of the voltage of No. 1 inverter output and idle.Three-phase when Fig. 6 show load time-varying
The simulation result figure in detection dead band be present in frequency-idle feedback transmitter.
Learnt by Fig. 6, the reactive power equilibrium of the photovoltaic system output of varying load at that time and feedback or each inverter are defeated
When going out reactive disturbance and interfering counteracting, for three-phase frequency-idle feedback transmitter there will be dead band, the frequency of voltage will be near 50Hz
Fluctuation, without departing from the threshold value of frequency.The idle change also with frequency of photovoltaic system output changes by a small margin, and 0
Near, and the idle sum of three photovoltaic systems is close to 0.
Using a kind of inverter disturbance formula isolated island detection combined based on electric voltage frequency and measurement impedance proposed by the present invention
Method, using the theory structure shown in Fig. 3, in the case where emulating same condition and parameter with failure Mechanism above, implemented
Checking.Time domain on-line measurement impedance plot when stable state and isolated island, as shown in Figure 7.
As seen from Figure 7, this method has higher accuracy of detection, has more significant impedance characteristic amount poor before and after isolated island
Different, therefore this method also has higher sensitivity.Meanwhile Fig. 7 shows, this method has a higher detection speed, after isolated island
Island state is quickly detected in 15ms.
Therefore, formula isolated island is disturbed by using a kind of inverter combined based on electric voltage frequency and measurement impedance of the present invention
Detection method, analyze and demonstrate the reason for detection of active class method isolated island is failed mechanism, to avoid isolated island detection failure from providing
Specific aim refers to；Because being injected using centralized disturbing signal, this method is not limited to by power supply type, can kept away independent of inverter
Exempt from more disturbing signal mutual interference failures under multiple inverter system scene, there is higher reliability；Frequency departure is not needed gradually to put
The big process to action threshold value, there is higher detection speed；Principle is easy and effective.
It should be noted that above-mentioned embodiment is only the preferable embodiment of the present invention, it is impossible to is understood as to this
The limitation of invention protection domain, under the premise of without departing from present inventive concept, to any minor variations that the present invention is done and modification
Belong to protection scope of the present invention.
Claims (2)
1. a kind of inverter combined based on electric voltage frequency and measurement impedance disturbs formula isolated island detection method, it is characterised in that described
Method comprises the following steps：
The relation of electric voltage frequency and the reactive power of inverter output at point of common coupling, draws energy before and after step 1, analysis isolated island
Change the frequency of point of common coupling by disturbing the idle output of inverter；
Step 2, control set the inverter of frequency-idle feedback transmitter, and the reactive power disturbance of system chooses point of common coupling electricity
Voltage-frequency rate faWith power network rated frequency fgDifference, in order that the change of less frequency obtains enough reactive disturbances to improve inspection
Degree of testing the speed, the feedback of frequency is added in disturbance quantity, add a feedback factor k, then the reactive power Q of inverter outputinv
=k (fa-fg)；
If the reactive power sum Σ Q of step 3, each inverter outputinv≠ 0, then exceeded according to the electric voltage frequency of combining inverter
The limitation of normal operation, detects island operation state, and system is not in if electric voltage frequency is without departing from the limitation of normal operation
Island operation state；If the reactive power sum ∑ Q of each inverter outputinv=0, then according to the electric voltage frequency of combining inverter
Whether beyond the limitation of normal operation judge that the detection method whether system island operation state occurs fails at this moment, perform
Step 4；
Step 4, one voltage source signal of injection is concentrated at system point of common coupling, the signal is single-frequency signals, injection
Mode is injected for three-phase, the injecting voltage and the data of current-responsive measured at acquisition system point of common coupling, through data processing
Afterwards, measurement impedance at system point of common coupling is calculated to obtain；The impedance Z of usual power networkGirdMuch smaller than the impedance Z of distributed power sourceDG
With the impedance Z of loadload,
ZGrid＜ ＜ ZDG,ZGrid＜ ＜ Zload
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After isolated island, measurement impedance Z at system point of common coupling 'measFor：
Z′meas=ZΙslanding＞ ＞ Zmeas
ZIslandingThe systematic survey impedance after isolated island generation is represented, impedance is carried out based on impedance characteristic difference before and after above isolated island
Mensuration isolated island detects.
2. the inspection of formula isolated island is disturbed according to a kind of inverter combined based on electric voltage frequency and measurement impedance described in claim 1
Survey method, it is characterised in that in the step 3, according to the electric voltage frequency of combining inverter beyond whether the limitation of normal operation come
Detect whether that the mechanism that the detection method for island operation state occur fails is：This method is defeated according to the change of system real-time frequency
Go out corresponding reactive power so that unbalanced due to reactive power after isolated island, the electric voltage frequency of islanded system is put because of positive feedback
The big limitation for exceeding normal operation, so as to detect island operation state.
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| CN106918754A (en) * | 2017-03-23 | 2017-07-04 | 华北电力大学 | A kind of direct-current micro-grid island detection method based on additional impedance |
| CN110350585A (en) * | 2019-07-26 | 2019-10-18 | 上海电力大学 | The isolated island of grid-connected photovoltaic system detects control method |
| CN111064233B (en) * | 2019-12-04 | 2022-10-04 | 中国电力科学研究院有限公司 | Method and system for distributing active and reactive current proportion of inverter |
| CN111103484B (en) * | 2019-12-19 | 2021-11-30 | 国网湖南省电力有限公司 | Island detection method, device and system based on hybrid power feedback disturbance |
| CN111682582B (en) * | 2020-05-21 | 2022-08-19 | 国网江苏省电力有限公司常州供电分公司 | Converter input control method and control system |
| CN116047188B (en) * | 2022-10-17 | 2023-11-07 | 中国人民解放军陆军工程大学 | Island detection method of power electronic transformer, electronic equipment and storage medium |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101867171A (en) * | 2010-06-28 | 2010-10-20 | 中国南方电网有限责任公司电网技术研究中心 | Distributed generator islanding detection method based on impedance measurement |
| CN102830307A (en) * | 2012-08-17 | 2012-12-19 | 西安交通大学 | Virtual inductance based positive feedback island detection method |
| CN103091578A (en) * | 2013-01-11 | 2013-05-08 | 天津理工大学 | Island detection method of photovoltaic grid-connected system |
| CN103207335A (en) * | 2013-03-21 | 2013-07-17 | 中国农业大学 | Island detection method based on phase-frequency positive feedback |
| CN103983873A (en) * | 2014-05-19 | 2014-08-13 | 国网宁夏电力公司 | Island detection method suitable for multi-inverter parallel operation and based on impedance measurement |
| EP2806280A1 (en) * | 2013-05-21 | 2014-11-26 | ABB Research Ltd. | Detecting electrical islands using wide-area measurements |
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2015
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101867171A (en) * | 2010-06-28 | 2010-10-20 | 中国南方电网有限责任公司电网技术研究中心 | Distributed generator islanding detection method based on impedance measurement |
| CN102830307A (en) * | 2012-08-17 | 2012-12-19 | 西安交通大学 | Virtual inductance based positive feedback island detection method |
| CN103091578A (en) * | 2013-01-11 | 2013-05-08 | 天津理工大学 | Island detection method of photovoltaic grid-connected system |
| CN103207335A (en) * | 2013-03-21 | 2013-07-17 | 中国农业大学 | Island detection method based on phase-frequency positive feedback |
| EP2806280A1 (en) * | 2013-05-21 | 2014-11-26 | ABB Research Ltd. | Detecting electrical islands using wide-area measurements |
| CN103983873A (en) * | 2014-05-19 | 2014-08-13 | 国网宁夏电力公司 | Island detection method suitable for multi-inverter parallel operation and based on impedance measurement |
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