Method for preventing islanding phenomenon on utility grid with a number of small scale PV systems

Kobayashi, Hiromu; Takigawa, Kiyoshi; Hashimoto, Eiji; Kitamura, Akio; Matsuda, H.

doi:10.1109/pvsc.1991.169299

Cited by 87 publications

(53 citation statements)

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“…Figure 2b shows the same NDZ for changes of voltage and frequency. Phase jump detection (PJD) involves monitoring the phase difference between the inverter's terminal voltage and its output current for a sudden "jump" [7,8]. Under normal operation and for current-source inverters, the inverter's output current waveform will be synchronized to the utility voltage by detecting the rising (or falling) zero crossings of v a at node "a" in Figure 1.…”

Section: Ndzmentioning

confidence: 99%

“…When the utility disconnects, the harmonic currents produced by the inverter will flow into the load, which in general has much higher impedance than the utility. The harmonic currents interacting with the larger load impedance will produce larger harmonics in v a [8]. These voltage harmonics, or the change in the level of voltage harmonics, can be detected by the inverter, which can then assume that the PV inverter is islanding and discontinue operation.…”

Section: Theory Of Operationmentioning

confidence: 99%

“…When current-source inverters are used, and when the switch that disconnects the utility voltage source from the island is on the primary side of the transformer, as shown in Figure 1, the secondary of the transformer will be excited by the output current of the PV inverter. However, because of the magnetic hysteresis and other non-linearities of the transformer, its voltage response is highly distorted [8] and will increase the THD in v a . There can also be non-linearities in the local load, such as rectifiers, which would similarly produce distortion in v a .…”

Section: Theory Of Operationmentioning

confidence: 99%

“…In theory, the voltage harmonic monitoring method promises to be highly successful in detecting islanding under a wide range of conditions [8], and its effectiveness should not change significantly in the multiple-inverter case.…”

Section: Strengthsmentioning

confidence: 99%

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Evaluation of Islanding Detection Methods for Utility-Interactive Inverters in Photovoltaic Systems

Bower¹,

Ropp²

2002

279

281

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This report describes the various methods and circuits that have been developed to detect an islanding condition for photovoltaic applications and presents three methods that have been developed to test those methods and circuits. Passive methods for detecting an islanding condition basically monitor parameters such as voltage and frequency and/or their characteristics and cause the inverter to cease converting power when there is sufficient transition from normal specified conditions. Active methods for detecting the island introduce deliberate changes or disturbances to the connected circuit and then monitor the response to determine if the utility grid with its stable frequency, voltage and impedance is still connected. If the small perturbation is able to affect the parameters of the load connection within prescribed requirements, the active circuit causes the inverter to cease power conversion and delivery of power to the loads. The methods not resident in the inverter are generally controlled by the utility or have communications between the inverter and the utility to affect an inverter shut down when necessary. This report also describes several test methods that may be used for determining whether the anti-islanding method is effective. The test circuits and methodologies used in the U.S. have been chosen to limit the number of tests by measuring the reaction of a single or small number of inverters under a set of consensus-based worst-case conditions. FOREWORDThis report has been prepared as part of Sandia National Laboratories' Photovoltaic Systems Research and Development work for the U.S. Department of Energy. Sandia is the DOE's lead laboratory for photovoltaic systems research. The development and approach for accomplishing meaningful systems goals for the nation's photovoltaic program and the photovoltaic industry is defined through five technical objectives: (1) reduce the life-cycle costs; (2) improve the reliability; (3) increase and assure the performance and safety of fielded systems; (4) remove barriers to the use of the technology; and (5) support market growth for commercial U.S. photovoltaic systems. This evaluation of the various islanding detection methods for photovoltaic inverters and utility-interactive power systems complements Sandia's photovoltaic inverter development and evaluation goals, provides valuable information for standards and codes input, and summarizes the strengths and weaknesses of the developed anti-islanding methods available today. ABSTRACTThis report describes the various methods and circuits that have been developed to detect an islanding condition for photovoltaic applications and presents methods that have been developed to test those methods and circuits. The methods described are separated into three categories. They are:

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Section: Ndzmentioning

confidence: 99%

Section: Theory Of Operationmentioning

confidence: 99%

Section: Theory Of Operationmentioning

confidence: 99%

Section: Strengthsmentioning

confidence: 99%

See 2 more Smart Citations

Evaluation of Islanding Detection Methods for Utility-Interactive Inverters in Photovoltaic Systems

Bower¹,

Ropp²

2002

279

281

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“…Phase Jump Detection -PJD) se dá pelo monitoramento da diferença de fase entre a tensão no PAC e a corrente de saída do inversor (BOWER; ROPP, 2002;KOBAYASHI et al, 1991). A Figura 2.8 ilustra uma típica implementação desse método.…”

Section: A Detecção De Ilhamento Através Do Método Detecção Do Salto unclassified

Estudo sobre a interação de métodos anti-ilhamento para sistemas fotovoltaicos conectados à rede de distribuição de baixa tensão com múltiplos inversores.

Silva¹

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Este trabalho estuda a interação entre os métodos anti-ilhamento aplicados em sistemas fotovoltaicos residenciais, operando simultaneamente em uma rede de distribuição de baixa tensão. Os sistemas fotovoltaicos em geral interagem entre si, com a rede de distribuição da concessionária e com outras fontes de geração distribuída. Uma consequência importante dessa interação é a ocorrência do ilhamento, que acontece quando as fontes de geração distribuída fornecem energia ao sistema elétrico de potência mesmo quando esta se encontra eletricamente isolada do sistema elétrico principal. A função anti-ilhamento é uma proteção extremamente importante, devendo estar presente em todos os sistemas de geração distribuída. Atualmente, são encontradas diversas técnicas na literatura. Muitas delas oferecem proteção adequada quando um inversor está conectado à linha de distribuição, mas podem falhar quando dois ou mais funcionam simultaneamente, conectados juntos ou próximos entre si. Dois destes métodos são analisados detalhadamente nesse estudo, avaliados em uma rede de distribuição residencial de baixa tensão. Os resultados obtidos mostram que a influência de um método sobre o outro é dependente da predominância de cada um deles dentro do sistema elétrico. Contudo, nas condições analisadas o ilhamento foi detectado dentro do limite máximo estabelecido pelas normas pertinentes. This work studies the interaction between islanding detection methods applied in residential photovoltaic systems, operating simultaneously in a low voltage distribution network. Photovoltaic systems, in general, interact with themselves, with the utility grid and other distributed generation sources. An important consequence of this interaction is the islanding occurrence, which happens when distributed generation sources supply energy to the electrical power system even when it is electrically isolated from the main electrical system. The anti-islanding function is an extremely important protection, and should be present in all distributed generation systems. Actually, many techniques are found in the literature. Most of them provide suitable protection when one inverter is connected to the distribution line, but can fail when two or more work simultaneously, connected at the same point or close to each other. Two of these methods are analyzed in detail in this study and evaluated in a residential low voltage distribution line. The obtained results show that the influence of a method over another one is dependent of the predominance of each one within the electrical system. However, in the analyzed condition the islanding was detected within the maximum allowed time established by applicable rules.

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Prevention of islanding in grid-connected photovoltaic systems

Ropp

Begović

Rohatgi

1999

Prog. Photovolt: Res. Appl.

114

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Method for preventing islanding phenomenon on utility grid with a number of small scale PV systems

Cited by 87 publications

References 1 publication

Evaluation of Islanding Detection Methods for Utility-Interactive Inverters in Photovoltaic Systems

Evaluation of Islanding Detection Methods for Utility-Interactive Inverters in Photovoltaic Systems

Estudo sobre a interação de métodos anti-ilhamento para sistemas fotovoltaicos conectados à rede de distribuição de baixa tensão com múltiplos inversores.

Prevention of islanding in grid-connected photovoltaic systems

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