CN104062529A - Island detection method - Google Patents
Island detection method Download PDFInfo
- Publication number
- CN104062529A CN104062529A CN201410324666.2A CN201410324666A CN104062529A CN 104062529 A CN104062529 A CN 104062529A CN 201410324666 A CN201410324666 A CN 201410324666A CN 104062529 A CN104062529 A CN 104062529A
- Authority
- CN
- China
- Prior art keywords
- voltage
- frequency
- threshold value
- island
- detection method
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Inverter Devices (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
Provided is an island detection method. A passive method and an active method are matched, an island can be detected out fast according to an overfrequency/underfrequency and an overvoltage/undervoltage method, and the quality of electric energy is not affected; when islanding occurs and power matching is formed in an island system, power matching of the system can be destroyed according to a capacitor switching method with harmonic detection as a criterion, voltage and frequency in the system are made to change, and consequently the island is detected out.
Description
Technical field
The invention belongs to extensive new forms of energy and concentrate grid-connected anti-island protect field, is the anti-island protect detection scheme that a kind of passive detection and active detecting combine, particularly the island detection method of voltage/frequency detection and harmonic wave Detection capacitance switching.
Background technology
Isolated island refers to after electric network fault, and distributed generation system is load supplying towards periphery still, thereby forms a uncontrollable local supply network.Unplanned isolated island serve serious problem can to the safe and stable operation band of electric system, as the voltage in isolated island and frequency uncontrollable, may cause damage to user's equipment; Circuit in isolated island is still charged, may jeopardize maintainer's personal safety etc.The Main Function that isolated island detects is, when distributed system and major network disengaging, to disconnect in time distributed power source, prevents unplanned islet operation.Conventional island detection method can be divided into remote detection method, passive detection method and active detecting method three major types at present.
Passive detection method is by gathering local signal, carries out isolated island detection in the situation that of additional any disturbance not, and conventional have voltage/frequency detection method, voltage harmonic detection method and a voltage-phase sudden change detection method etc.Its advantage is that principle is simple, and equipment investment is few, is easy to realize, noiseless to electrical network, on the quality of power supply without impact; Under many inverters, detection efficiency can not reduce, and shortcoming is that detection blind area is larger.
Wherein, voltage/frequency detection method is by detecting voltage and the frequency of PCC (electrical network points of common connection), judging whether grid-connected system island state occurs.During normal operation, DG (distributed power generation) system output voltage or frequency are clamped down on by large line voltage, can not change.When island state, DG system is not clamped down on by large line voltage, if the output power of DG system inverter and local load power are uneven, output voltage or frequency will change.If voltage and frequency change have surpassed the normality threshold of setting, isolated island can be detected and occur.General combining inverter can configure overvoltage protection (OVR), under-voltage protection (UVR), over frequency protection (OFR), four kinds of protections of underfrequency protection (UFR); these protections be detect island effect the most substantially, the most direct method; once line voltage, the paranormal scope of frequency be detected; be judged as isolated island and occur, holding circuit just cuts off electrical network by combining inverter.But when DG system output power and local bearing power, to be close to after grid cut-off, PCC is ordered while mating voltage and frequency change very little, and these variable quantities are not enough to start OVR/UVR and OFR/UFR, and isolated island detects unsuccessfully.Meanwhile, for preventing that the normal fluctuation of line voltage and frequency from causing misoperation, the threshold value of four kinds of protections can not arrange too low, causes existing larger detection blind area.
Active detecting method is to detect judgement by artificially introducing small voltage, electric current or frequency disturbance signal to system, and that commonly uses has impedance measurement, reactance insertion, variation method, power disturbance method, active frequency drift method and a sliding formwork frequency drift etc.Advantage is when distributed power source output power is mated with load power demand, active method still can detect isolated island, blind area is less, sensitivity is higher, shortcoming be as the disturbance of drawing-in system control improper, cannot stable operation after can causing micro-electrical network to enter island state.
Wherein, external switch capacitance detecting method be near the relay region of mating with local load capacity at DG, install additional can automatic switching electric capacity, change system load impedance, when municipal power failure, being about to electric capacity is incorporated to, by reactive power, destroy system balancing, can judge whether to occur isolated island by the ANOMALOUS VARIATIONS of voltage, frequency being detected.This method has two kinds of implementations, a kind of is periodicity switching capacitance, a time interval is set, every one or several cycle capacitance switch state by being disconnected to closure, after certain hour, disconnect, so repeatedly, if at capacitance switch period of contact generation isolated island, electric capacity will change the output power of islanded system.But adopt the method that periodically drops into capacitor, if the electric capacity dropping into is larger, while being incorporated into the power networks, may uninterruptedly cause voltge surge to the less distribution network system of capacity, the quality of power supply is had a certain impact; Secondly, this method is higher to switch reliability requirement, and periodicity switching can shorten the serviceable life of switch.The second is to match with PCC point place switch, as switch S in Fig. 11, and when switch S 1 disconnects, switch S 2 closures, external capacitor is incorporated to system, destroys the power-balance of system.The shortcoming of the method is that the switching of electric capacity will coordinate with the switch at PCC point place, PCC point switch must be detected and disconnect and could drop into electric capacity, if pick-up unit breaks down, and isolated island detection general failure.In addition, the method must be found power match point, but the trend of electric system is often to change, and is difficult to find fixing power match point.
Comprehensive above analyze knownly, voltage/frequency detection method can effectively detect isolated island when uneven in the output power of DG system inverter and local load power, but when the output power of DG system inverter and local load power balance, the method inefficacy.And external switch capacitance detecting method can effectively detect isolated island when the output power of DG system inverter and local load power balance, but high or need to coordinate with PCC point switch to switch performance requirement.Therefore, can be in conjunction with voltage/frequency detection method and external switch capacitance detecting method advantage separately, and do suitable improvement, and find out a kind of more effectively practical island detection method, realize and detect non-blind area.
Summary of the invention
For ensureing the stationarity of micro-operation of power networks state conversion, consider accuracy of detection, sensitivity and the disturbance impact on system stable operation simultaneously, the application proposes a kind of micro-electrical network feature that is applicable to, take passive detection as main, active detecting is auxiliary combination decision isolated island detection scheme: adopted/under-frequency of the passive means of this programme and mistake/under-voltage detection method, active method adopts take the capacitor switching method that percent harmonic distortion is criterion.First this scheme utilizes mistake/under-frequency device and the mistake/under-voltage device that inverter carries to detect in real time frequency and the voltage that PCC is ordered, any place installing harmonic measurement device in DG system, detect in real time percent harmonic distortion, do not need to look for again power match point that installation is set.Capacitor is connected with harmonic measurement device by switch, and controlled by it.Schematic diagram is shown in Fig. 2, if harmonic measurement device detects percent harmonic distortion, has exceeded the threshold value of setting, and the frequency that mistake/under-frequency device and mistake/under-voltage device detects, voltage surpass threshold value, and now possible reason is:
1, the disturbance of system itself, as neighbouring, have high ferro through or large steel-making plant making steel or transient fault etc. occurred;
2, when the output power of DG system inverter and local load power balance, there is isolated island.
Consider the possibility of generation systems disturbance, the time delay that 1s is set escapes the reclosure time after ringing action time and failure removal, in 1s time delay, if percent harmonic distortion is lower than threshold value, voltage, frequency do not exceed threshold value yet, illustrate that original harmonic distortion is that disturbance by system itself causes or automatic reclosing overlaps PCC switch, isolated island does not occur, after 1s time delay finishes, percent harmonic distortion still exceeds threshold value, and voltage, frequency does not exceed threshold value, now may there is isolated island in explanation, and the power that inverter sends mates with local load power, by switch S 2 closures, drop into electric capacity, destroy system balancing, make voltage, frequency has greatly changed, inverter can detect these variations, in 2s, detect isolated island, stop power supply and (according to China's photovoltaic system interconnection technology, require the requirement of GB/T19939-2005, when isolated island occurs, should in 2s, detect isolated island, if cannot detect isolated island in 2s, be considered as detecting unsuccessfully).
Based on harmonic wave Detection capacitance switching and voltage/frequency, detect the island detection method matching and comprise the following steps, its process flow diagram is shown in Fig. 3:
Step 1: utilized/under-frequency device and mistake/under-voltage device detects frequency and the voltage that PCC is ordered in real time, utilizes active detection method, that is, harmonic measurement device detects percent harmonic distortion in real time;
Step 2: judge whether detected frequency, voltage have surpassed the threshold value of setting, and if so, carry out step 5, if not, return to the first step; Judge whether percent harmonic distortion has exceeded threshold value, if so, carry out step 3; If not, carry out step 1;
Step 3: start time delay 1S, all do not exceed threshold value if voltage, frequency, percent harmonic distortion detected after time delay 1S finishes, return to step 1; If percent harmonic distortion detected after time delay 1S finishes, still exceed threshold value, and voltage, frequency do not exceed threshold value, carry out step 4;
Step 4: Closing Switch S1, drops into electric capacity, uses inverter to measure voltage and the frequency of islanded system, if voltage and frequency exceed threshold values, performs step five, if do not exceed threshold values, returns to step 1;
Step 5: be judged to be isolated island.
Beneficial effect of the present invention is: the application is a kind of isolated island detection scheme that passive means is matched with active method, in most of the cases, after there is isolated island, islanded system internal power does not mate, voltage and frequency can have greatly changed, now adopted/under-frequency and mistake/under-voltage method can fast detecting go out isolated island, and on not impact of the quality of power supply; After there is isolated island and during islanded system internal power coupling, adopt and using harmonic wave and detect the capacitor switching method as criterion, can destroy the power match of system, intrasystem voltage and frequency are changed, thereby detect isolated island.Compare with traditional passive detection method, this programme can detect power matching state, and has dropped into electric capacity when power match, can mate by breakdown power, does not exist and detects blind area; Compare with traditional active detecting method, this programme does not affect the quality of power supply when grid-connected inverters moves, and only need simply transform in net side, can use mistake/under-frequency and the mistake/under-voltage protection that inverter itself has can realize detection, need on every inverter, not install new algorithm additional, be easy to realize; Compare with traditional capacitor switching method, this programme is used percent harmonic distortion as start-up criterion, and without coordinating with PCC on off state, without the point of finding power match, and detection efficiency and device installation is location-independent, is easy to realization.Therefore, new method does not exist and detects blind area, little on quality of power supply impact, can realize isolated island measuring ability fast and effectively, has practical meaning in engineering.
Accompanying drawing explanation
Fig. 1 is traditional external switch capacitance detecting method schematic diagram;
Fig. 2 is the schematic diagram based on harmonic wave Detection capacitance switching island detection method;
Fig. 3 detects the process flow diagram of the island detection method matching based on harmonic wave Detection capacitance switching and voltage/frequency;
When being isolated island, Fig. 4 (a) detects the harmonic wave analogous diagram of the island detection method matching based on harmonic wave Detection capacitance switching and voltage/frequency;
When being isolated island, Fig. 4 (b) detects the common point voltage analogous diagram of the island detection method matching based on harmonic wave Detection capacitance switching and voltage/frequency;
When being isolated island, Fig. 4 (c) detects the common point frequency analogous diagram of the island detection method matching based on harmonic wave Detection capacitance switching and voltage/frequency.
Embodiment
Below in conjunction with accompanying drawing, the present invention is further described.
Based on harmonic wave Detection capacitance switching and voltage/frequency, detecting the island detection method matching comprises the following steps:
Step 1: utilized/under-frequency device and mistake/under-voltage device detects frequency and the voltage that PCC is ordered in real time, utilizes active detection method, that is, harmonic measurement device detects percent harmonic distortion in real time;
Step 2: judge whether detected frequency, voltage have surpassed the threshold value of setting, and if so, carry out step 5, if not, return to the first step; Judge whether percent harmonic distortion has exceeded threshold value, if so, carry out step 3; If not, carry out step 1;
Step 3: start time delay 1S, all do not exceed threshold value if voltage, frequency, percent harmonic distortion detected after time delay 1S finishes, return to step 1; If percent harmonic distortion detected after time delay 1S finishes, still exceed threshold value, and voltage, frequency do not exceed threshold value, carry out step 4;
Step 4: Closing Switch S1, drops into electric capacity, uses inverter to measure voltage and the frequency of islanded system, if voltage and frequency exceed threshold values, performs step five, if do not exceed threshold values, returns to step 1;
Step 5: be judged to be isolated island.
Detection criteria is as follows:
(1) in GB12326-90, stipulate, to weigh point be ratings for points of common connection voltage allows skew ± 5%, if perunit value is arrived in conversion, when common point voltage being detected, is greater than 1.05 or be judged to be isolated island while being less than 0.95.
(2) in GB/T15945-95, stipulate, the deviation allowing for electric system, normally allows for ± 0.2Hz, and for can be loosened to ± 0.5Hz of low capacity system, microgrid belongs to low capacity system, and frequency detecting criterion is set as f
min=45.5Hz, f
max=50.5Hz, the common point electric voltage frequency detecting is less than 45.5Hz or is greater than 50.5Hz, is judged to be isolated island.
(3) in GB/T14549-93, stipulate, the measurement point of 380V electric pressure is for the mains by harmonics aberration rate THD of points of common connection is 5% (0.05), when percent harmonic distortion being detected and being greater than 5% (0.05), judges that electrical network occurs abnormal.
Figure 4 shows that the isolated island detection simulation figure that uses the inventive method to obtain, isolated island occurred since the 4th second, within the 5th second, drop into capacitor C=0.0001F.Fig. 4 (a) has provided the harmonic wave analogous diagram based on the method, and as can be seen from the figure after within the 4th second, there is isolated island, percent harmonic distortion has just surpassed 5%, and 1 second percent harmonic distortion of time delay still surpasses 5%; Fig. 4 (b) has provided the common point voltage analogous diagram based on the method, as can be seen from the figure at the 4th second, occurs after isolated island, and due to system power coupling, voltage is substantially unchanged, time delay after 1 second voltage still unchanged, do not exceed threshold value; Fig. 4 (c) has provided the common point frequency analogous diagram based on the method, as can be seen from the figure at the 4th second, occurs after isolated island, and due to system power coupling, frequency change is very little, time delay after 1 second frequency change still very little, do not exceed threshold value.At the 5th second, drop into electric capacity, from analogous diagram, can find out, percent harmonic distortion on the contrary than little before not throwing, illustrates that the capacitance of selecting is suitable after dropping into electric capacity, and System Reactive Power power is provided, and has reduced percent harmonic distortion; Common point voltage reduces rapidly after dropping into electric capacity, exceeds threshold value; Common point frequency also reduces rapidly, exceeds threshold value.Voltage/frequency pick-up unit starts island protect and moves rapidly, and isolated island detects successfully.
Claims (5)
1. an island detection method, comprises the following steps:
Step 1: utilized/under-frequency device and mistake/under-voltage device detects frequency and the voltage that PCC is ordered in real time, utilizes harmonic measurement device to detect in real time percent harmonic distortion;
Step 2: judge whether detected frequency, voltage have surpassed the threshold value of setting, and if so, carry out step 5, if not, return to the first step; Judge whether percent harmonic distortion has exceeded threshold value, if so, carry out step 3; If not, carry out step 1;
Step 3: start time delay 1S, all do not exceed threshold value if voltage, frequency, percent harmonic distortion detected after startup time delay 1S finishes, return to step 1; If percent harmonic distortion detected after time delay 1S finishes, still exceed threshold value, and voltage, frequency do not exceed threshold value, carry out step 4;
Step 4: Closing Switch S1, drops into electric capacity, uses inverter to measure voltage and the frequency of islanded system, if voltage and frequency exceed threshold values, performs step five, if do not exceed threshold values, returns to step 1;
Step 5: be judged to be isolated island.
2. island detection method according to claim 1, is characterized in that, the threshold value of frequency described in step 2 is f
min=45.5Hz, f
max=50.5Hz.
3. island detection method according to claim 1, is characterized in that, the threshold value of voltage described in step 2 is the side-play amount that points of common connection voltage allows, its scope is ratings ± and 5%.
4. island detection method according to claim 1, is characterized in that, percent harmonic distortion described in step 3 is 5%.
5. island detection method according to claim 1, is characterized in that the capacitor C=0.0001F dropping into described in step 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410324666.2A CN104062529B (en) | 2014-07-09 | 2014-07-09 | A kind of island detection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410324666.2A CN104062529B (en) | 2014-07-09 | 2014-07-09 | A kind of island detection method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104062529A true CN104062529A (en) | 2014-09-24 |
| CN104062529B CN104062529B (en) | 2017-06-13 |
Family
ID=51550333
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410324666.2A Expired - Fee Related CN104062529B (en) | 2014-07-09 | 2014-07-09 | A kind of island detection method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104062529B (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104655957A (en) * | 2015-01-28 | 2015-05-27 | 东南大学 | Active and passive integrated mixed island detection method |
| CN105974238A (en) * | 2016-06-20 | 2016-09-28 | 重庆瑜欣平瑞电子股份有限公司 | Automatic testing method and automatic testing system for gasoline engine inverter |
| CN104267317B (en) * | 2014-10-21 | 2017-02-22 | 华北电力大学 | Islanding detection method based on reactance layered switching |
| CN107422196A (en) * | 2017-02-27 | 2017-12-01 | 国电南瑞科技股份有限公司 | A kind of island detection method based on percent harmonic distortion and frequency |
| CN107526009A (en) * | 2017-09-13 | 2017-12-29 | 国电南瑞科技股份有限公司 | It is a kind of that Interlocking Methods are detected according to the isolated island of frequency and curent change sequential |
| CN107765108A (en) * | 2016-08-18 | 2018-03-06 | 华为技术有限公司 | A kind of island detection method of inverter, device and electric power system |
| CN107918082A (en) * | 2016-10-10 | 2018-04-17 | 中国电力科学研究院 | A kind of island detection method of inverter parallel |
| CN110632413A (en) * | 2019-09-02 | 2019-12-31 | 国网吉林省电力有限公司 | Reactive power disturbance island detection method triggered in delayed mode |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0450672A (en) * | 1990-06-12 | 1992-02-19 | Kansai Electric Power Co Inc:The | Fault detecting method for electric power system using two parallel circuits |
| CN101847876A (en) * | 2010-05-28 | 2010-09-29 | 上海理工大学 | Three-phase photovoltaic grid connected inverter system |
| CN101944746A (en) * | 2010-07-20 | 2011-01-12 | 郑军 | Island detection method, device and system of photovoltaic grid-connected power generating system |
| CN102255329A (en) * | 2011-04-14 | 2011-11-23 | 东南大学 | Island detection method of photovoltaic grid connected system |
| CN103064035A (en) * | 2013-01-08 | 2013-04-24 | 天津大学 | Active island detection method of multi-distributed power supply tied-grid |
| 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 |
| CN103323695A (en) * | 2013-05-16 | 2013-09-25 | 国家电网公司 | Device and method for automatically loading anti-islanding protection test system |
| CN103412207A (en) * | 2013-07-11 | 2013-11-27 | 华北电力大学（保定） | Photovoltaic grid connected inverter island detection method based on negative sequence current injection |
| KR20130135520A (en) * | 2012-06-01 | 2013-12-11 | 엘에스산전 주식회사 | A power monitoring system and a method for displaying information of a power system |
| CN103645404A (en) * | 2013-12-16 | 2014-03-19 | 辽宁工业大学 | Micro-grid islanding detection method |
-
2014
- 2014-07-09 CN CN201410324666.2A patent/CN104062529B/en not_active Expired - Fee Related
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0450672A (en) * | 1990-06-12 | 1992-02-19 | Kansai Electric Power Co Inc:The | Fault detecting method for electric power system using two parallel circuits |
| CN101847876A (en) * | 2010-05-28 | 2010-09-29 | 上海理工大学 | Three-phase photovoltaic grid connected inverter system |
| CN101944746A (en) * | 2010-07-20 | 2011-01-12 | 郑军 | Island detection method, device and system of photovoltaic grid-connected power generating system |
| CN102255329A (en) * | 2011-04-14 | 2011-11-23 | 东南大学 | Island detection method of photovoltaic grid connected system |
| KR20130135520A (en) * | 2012-06-01 | 2013-12-11 | 엘에스산전 주식회사 | A power monitoring system and a method for displaying information of a power system |
| CN103064035A (en) * | 2013-01-08 | 2013-04-24 | 天津大学 | Active island detection method of multi-distributed power supply tied-grid |
| 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 |
| CN103323695A (en) * | 2013-05-16 | 2013-09-25 | 国家电网公司 | Device and method for automatically loading anti-islanding protection test system |
| CN103412207A (en) * | 2013-07-11 | 2013-11-27 | 华北电力大学（保定） | Photovoltaic grid connected inverter island detection method based on negative sequence current injection |
| CN103645404A (en) * | 2013-12-16 | 2014-03-19 | 辽宁工业大学 | Micro-grid islanding detection method |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104267317B (en) * | 2014-10-21 | 2017-02-22 | 华北电力大学 | Islanding detection method based on reactance layered switching |
| CN104655957A (en) * | 2015-01-28 | 2015-05-27 | 东南大学 | Active and passive integrated mixed island detection method |
| CN105974238A (en) * | 2016-06-20 | 2016-09-28 | 重庆瑜欣平瑞电子股份有限公司 | Automatic testing method and automatic testing system for gasoline engine inverter |
| CN105974238B (en) * | 2016-06-20 | 2019-07-23 | 重庆瑜欣平瑞电子股份有限公司 | Gasoline engine inverter automatic test approach and system |
| CN107765108B (en) * | 2016-08-18 | 2020-01-21 | 华为技术有限公司 | Island detection method and device of inverter and power supply system |
| CN107765108A (en) * | 2016-08-18 | 2018-03-06 | 华为技术有限公司 | A kind of island detection method of inverter, device and electric power system |
| US10488450B2 (en) | 2016-08-18 | 2019-11-26 | Huawei Technologies Co., Ltd. | Islanding detection method and apparatus for inverter, and power supply system |
| CN107918082B (en) * | 2016-10-10 | 2021-01-15 | 中国电力科学研究院 | Island detection method for parallel operation of inverters |
| CN107918082A (en) * | 2016-10-10 | 2018-04-17 | 中国电力科学研究院 | A kind of island detection method of inverter parallel |
| CN107422196A (en) * | 2017-02-27 | 2017-12-01 | 国电南瑞科技股份有限公司 | A kind of island detection method based on percent harmonic distortion and frequency |
| CN107422196B (en) * | 2017-02-27 | 2019-12-06 | 国电南瑞科技股份有限公司 | Island detection method based on harmonic distortion rate and frequency |
| CN107526009A (en) * | 2017-09-13 | 2017-12-29 | 国电南瑞科技股份有限公司 | It is a kind of that Interlocking Methods are detected according to the isolated island of frequency and curent change sequential |
| CN110632413A (en) * | 2019-09-02 | 2019-12-31 | 国网吉林省电力有限公司 | Reactive power disturbance island detection method triggered in delayed mode |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104062529B (en) | 2017-06-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104062529A (en) | Island detection method | |
| Telukunta et al. | Protection challenges under bulk penetration of renewable energy resources in power systems: A review | |
| US9170306B2 (en) | Islanding detection method and system | |
| CN102183733B (en) | Photovoltaic grid connected inverter island detection method for improving quality of electric energy | |
| CN103124068B (en) | A kind of anti-island protect system of distributed power generation grid-connected system and guard method thereof | |
| WO2007033505A1 (en) | Method for detecting islanding operation of a distributed generator | |
| KR101904815B1 (en) | PCS for ESS and PCS Operating Method thereof | |
| CN103217595B (en) | A kind of detection method of one-phase island of three-phase grid-connected inverter, equipment and system | |
| CN203747436U (en) | Distributed photovoltaic power generation access system | |
| WO2021000682A1 (en) | Direct current islanding detection method based on positive feedback of bus voltage having specific frequency | |
| US9419428B2 (en) | Protection device for DC collection systems | |
| Tziouvaras | Relay performance during major system disturbances | |
| CN106026160A (en) | Distributed photovoltaic generation anti-islanding protective device | |
| Chandrakar et al. | An assessment of distributed generation islanding detection methods | |
| Deshmukh et al. | Overview of dynamic voltage restorer (DVR) for power quality improvement | |
| CN104882904A (en) | Novel photovoltaic power station passive anti-islanding protection method | |
| CN103475022B (en) | Photovoltaic power station system with low voltage crossing and anti-isolated island defencive function | |
| CN103887811A (en) | Distributed power supply system and control method with low voltage ride through and anti-islanding protective functions | |
| WO2020057860A1 (en) | Method of controlling a renewable power generation plant during network ground fault | |
| CN104267317B (en) | Islanding detection method based on reactance layered switching | |
| CN211063355U (en) | Energy storage inverter controlled by grid-connected and off-grid fast switching | |
| Abdolrasol et al. | Hybrid anti-islanding algorithm for utility interconnection of distributed generation | |
| Moradzadeh et al. | A novel hybrid islanding detection method for distributed generations | |
| Yan et al. | Islanding of distribution networks: challenges and potential solutions | |
| CN103529323A (en) | Dead zone reduction method for passive island detection of micro-grid |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20170613 Termination date: 20190709 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |