• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.34-40
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• 2013

Islanding phenomenon of photovoltaic system is undesirable because it leads to a safety hazard to utility service personnel and may cause damage to power generation and power supply facilities as a result of unsynchronized re-closure. Anti-islanding protection is an important technical requirement for grid-connected PV system. Until now, various anti-islanding methods for detecting and preventing islanding of photovoltaic and other distributed generations have been proposed. Most of them are focusing on the anti-islanding performance of single PV system according to the related international and domestic standard test procedures. There are few studies on the islanding phenomenon for multiple photovoltaic operation in parallel. This paper presents performance analysis of anti-islanding function for grid-connected PV inverter systems when several PV inverters are connected in parallel.

• Journal of the Korean Solar Energy Society
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• v.29 no.6
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• pp.75-80
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• 2009

Recently, as the grid-connected photovoltaic power conditioning systems (PVPCS) are installed in many residential areas, these have raised potential problems of network protection on electrical power system. One of the numerous problems is an Islanding phenomenon. In this paper, active frequency drift (AFD) method, one of the anti-islanding methods which is analyzed by current magnitude compensation and calculation of RMS value of the output power is proposed and verified by simulation.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.297-302
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• 2009

As the grid-connected photovoltaic power conditioning systems (PVPCS) are installed in many residential areas, these have raised potential problems of network protection on electrical power system. One of the numerous problems is an Islanding phenomenon. In this paper, active frequency drift (AFD) method, one of the anti-islanding analyzed by current magnitude compensation and calculation of RMS value of the output power.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.270-271
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• 2007

본 논문에서는 분산전원을 배전계통에 연계할 때 지켜야 할 계통연계기준과 분산전원의 전력계통 연계기술 중 계통과의 동기화, 역조류, 단독운전 방지에 대한 현재 기술개발동향을 알아보고 상세히 분석하였다.

• 전기의세계
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• v.45 no.1
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• pp.7-9
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• 1996

분산형전원 (Dispersed Storage and Generation System)이란 원자력이나 대용량 화력 등과 같은 집중적이고 대용량이 아닌 소용량의 전력저장시스템이나 발전시스템을 일컫는 말로서 소수력, 태양광, 바이오, 풍력 등의 대체에너지 전원, 소용량의 열병합발전시스템, 전기 등을 이용한 전력 저장시스템이 그 예라 하겠다. 이러한 분산형전원은 그 단어 뜻대로 대규모 전력계통에 비하여 분산되어 있기 때문에 관리가 어렵고 전력계통에 연계될 경우 여러가지 문제를 야기시키게 된다. 이러한 문제중 가장 큰 것은 계통의 전압변동의 요인이 되는 것이고 보호협조 문제 또한 무시할 수 없는 것이다. 더우기 보안상 단독운전이 될 경우를 방지하여야 하고 고조파문제, 계통단락용량 증대문제 등도 염려가 되는 문제이다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.57-62
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• 2010

Renewable energy and smart grid become the focus of attention of industry. The smart grid is an intelligent system which maximizes the efficiency of energy and it needs to monitor the amount of power generation and power consumption continuously. Remote Monitoring System(RMS) is very useful for monitoring the power generation and consumption, but mostly they are implemented on the wire communication. In this paper, we propose a wireless sensor network based remote power monitoring system. And as an application, a new anti-islanding method with the proposed RMS is presented. An experimental micro grid system is implemented to verify the proposed RMS and anti-islanding method.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.602-605
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• 2003

분산전원용 계통연계 인버터가 효율적인 분산전원으로 사용되기 위해서는 기존 계통과 협조 운전이 필요하다. 따라서 전류제어 외에 무효전력의 제어, 계통과 연계시의 PLL 제어, 단독운전 방지 제어 등의 다양한 기능이 필요하다. 그러나 단상 시스템의 경우, 3상 시스템과 달리 교류전력을 다뤄야 하므로, 제어 시 위상 지연이 발생하게 되고 무효전력을 제어하기 어려운 문제점등이 발생된다 따라서 본 논문에서는 이러한 문제점을 해결하기 위해 dq 모델을 단상시스템에 적용하여 단상 제어의 문제점을 보완하였다.

• Journal of the Korean Solar Energy Society
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• v.28 no.2
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• pp.64-69
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• 2008

As the grid-connected photovoltaic power conditioning systems (PVPCS) are installed in many residential areas, these have raised potential problems of network protection on electrical power system. One of the numerous problems is an Islanding phenomenon. There has been an argument that it may be a non-issue in practice because the probability of islanding is extremely low. However, there are three counter-arguments: First, the low probability of islanding is based on the assumption of 100% power matching between the PVPCS and the islanded local loads. In fact, an islanding can be easily formed even without 100% power matching (the power mismatch could be up to 30% if only traditional protections are used, e.g. under/over voltage/frequency). The 30% power-mismatch condition will drastically increase the islanding probability. Second, even with a larger power mismatch, the time for voltage or frequency to deviate sufficiently to cause a trip, plus the time required to execute a trip (particularly if conventional switchgear is required to operate), can easily be greater than the typical re-close time on the distribution circuit. Third, the low-probability argument is based on the study of PVPCS. Especially, if the output power of PVPCS equals to power consumption of local loads, it is very difficult for the PVPCS to sustain the voltage and frequency in an islanding. Unintentional islanding of PVPCS may result in power-quality issues, interference to grid-protection devices, equipment damage, and even personnel safety hazards. Therefore the verification of anti-islanding performance is strongly needed. In this paper, improved RPV method is proposed through considering power quality and anti-islanding capacity of grid-connected single-phase PVPCS in IEEE Std 1547 ("Standard for Interconnecting Distributed Resources to Electric Power Systems"). And the simulation results are verified.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.351-352
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• 2016

Since anti-islanding scheme of grid-connected inverter is a key function of standards compliance, unintentional islanding results in safety hazards, reliability, and many other issues. Therefore, many anti-islanding schemes have been researched, however, existing anti-islanding schemes show poor power quality and non-detection zone issues. Besides, most of them have problems which deteriorate performance of islanding detection under parallel-operation. Therefore, this paper proposes a new anti-islanding scheme that has both negligible power quality degradation, no non-detection zone and precise islanding detection under parallel-operation. Finally, both simulation and experimental results validate the proposed scheme.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.299-301
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• 2009

In this paper, a novel anti-islanding method of DC-AC single phase inverter is proposed. The inverter injects a little harmonic current with the output current of a PCS(Power Conditioning System). When the islanding condition is occurred, the voltage harmonic components appear on the output voltage of the PCS due to the injection of a little harmonic current. So, the PCS detects the voltage harmonic components using the Goertzel algorithm, and then the PCS decides that the islanding condition is occurred. When the PCS recognizes the islanding condition, the PCS are stopped. The proposed a novel anti-islanding method is analyzed, and its validity is proven through simulation.