A high speed frequency shift method as a protection for islanding phenomena of utility interactive PV systems

Yuyama, S.; Ichinose, Takashi; Kimoto, K.; Itami, Toshio; Ambo, Tatsuaki; Okado, C.; Nakajima, Kazuyoshi; Hojo, Satoru; Shinohara, Hirofumi; Ioka, S.; Kuniyoshi, Mizuki

doi:10.1016/0927-0248(94)90176-7

Cited by 34 publications

(15 citation statements)

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“…However, it is known that some RLC loads have phase response curves such that the phase of the load increases faster than the phase of the PV inverter [1,16]. This problem is demonstrated in Figure 6, which shows several RLC loads with frequency responses that defeat the instability of this particular SMS curve.…”

Section: Ndzmentioning

confidence: 95%

“…The frequency bias or active frequency drift (AFD) method is easily implemented in a PV inverter with a microprocessor-based controller [16]. In this method, the waveform of the current injected into node "a" by the PV inverter is slightly distorted such that there is a continuous trend to change the frequency.…”

Section: Theory Of Operationmentioning

confidence: 99%

“…In effect, the inverter is measuring dv a /di PV-inv , and for this reason, this method is often called the impedance measurement method [15,16,17,18]. As the inverter can be loaded so that the islanding voltage would fall to the limit of the grid-connected UVP/OVP window, the minimum current shift required for island detection is equal to the full UVP/OVP window size.…”

Section: Theory Of Operationmentioning

confidence: 99%

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

Bower¹,

Ropp²

2002

278

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: 95%

Section: Theory Of Operationmentioning

confidence: 99%

Section: Theory Of Operationmentioning

confidence: 99%

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

Bower¹,

Ropp²

2002

278

281

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“…A few examples of active methods of detection are, slidemode frequency shift (SMS) [11], active frequency drift and Sandia frequency shift (SFS) [11][12][13][14], Sandia voltage shift (SVS) [11], methods based on impedance measurement by harmonic injection [15][16][17][18], impedance measurement by output power shift [8] and impedance measurement by active frequency drift [9].…”

Section: I! Introductionmentioning

confidence: 99%

PWM harmonic signature based islanding detection for a single-phase inverter with PWM frequency hopping

Colombage

Wang

Gould

et al. 2015

2015 IEEE Energy Conversion Congress and Exposition (ECCE)

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--Distributed generation (DG) has gained popularity in recent years due to the increasing requirement for renewable power sources. A problem that exists with DG systems is the islanding of DG units that creates safety issues for personnel as well as the potential for damage to utility infrastructure. Therefore, islanding detection methods are utilized to mitigate the risk of islanded operation of DG units. A new passive method of islanding detection based on the signature of the PWM voltage harmonics is proposed. The viability of the algorithm is investigated with the use of an analytical and time domain model of the inverter and further validated with experimental results. Furthermore, an extension of the detection scheme is proposed for use in multiinverter scenarios composed of adaptive frequency hopping to eliminate unwanted tripping.

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“…4,5 Several islanding detection techniques can be found in the literature. 1,2,4,5,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] They can be mainly classified in two groups: passive and active methods. The passive methods try to detect islanding by means of observing the evolution of the inverter output electrical variables.…”

Section: Introductionmentioning

confidence: 99%

Design methodology for the frequency shift method of islanding prevention and analysis of its detection capability

Sanchis

Marroyo

Coloma

2005

Prog. Photovolt: Res. Appl.

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Islanding protection is one of the most important sources of discrepancy in gridconnected photovoltaic systems. Even when islanding is not very likely to happen, regulations demand the photovoltaic inverters to implement effective protection methods. Due to its several advantages, the frequency shift method of islanding prevention, commonly known as Sandia Frequency Shift, is one of the most important active methods. This method implements a positive feedback of the frequency that tends to move it outside the trip limits in case of islanding. The method shows a very high detection capability, which depends on both the values of the method parameters and the characteristics of the load that remains in the same power section after islanding. This paper develops a mathematical analysis of the Sandia Frequency Shift method and proposes a new methodology to design its parameters as a trade-off between the detection capability, which is evaluated as a function of the load characteristics, and the distortion that the method could introduce in the grid as a consequence of transitory frequency disturbances. The ability of this methodology to design the method parameters and achieve the highest detection capability is satisfactorily proved by means of both simulation and experimental results on a commercial photovoltaic inverter that implements the method once its parameters have been designed with the proposed methodology.

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A high speed frequency shift method as a protection for islanding phenomena of utility interactive PV systems

Cited by 34 publications

References 0 publications

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

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

PWM harmonic signature based islanding detection for a single-phase inverter with PWM frequency hopping

Design methodology for the frequency shift method of islanding prevention and analysis of its detection capability

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