24-12-2012, 01:07 PM
An Islanding Detection Method for a Grid-Connected System Based on the Goertzel Algorithm
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Abstract:
Islanding refers to a condition of a distributed generator (DG) in that it continues to power a location even though power from the grid is no longer present. This condition can be dangerous to grid workers who may not realize that the load is still powered even though there is no power from the grid. Adverse effects of islanding are low power quality, grid-protection interference, equipment damage, and personnel safety hazards. For these reasons, DG systems must detect an islanding condition and immediately stop producing power; this is referred to as anti-islanding. Islanding detection methods can be categorized into two major approaches: the passive and active methods. The passive methods are based on measurement of the natural effects of islanding. The active methods use intentional transients or harmonic effects. When the power generated by the DG matches the load power consumption, passive methods fail due to the small natural effects of islanding. Therefore, the passive methods have a non detection zone (NDZ).The active method scan reduce the NDZ size. However, these methods reduce the grid power quality. In this paper, a novel anti-islanding method (AIM) is proposed. A single-phase DG using the proposed AIM injects the output current with a little harmonic current into the grid and monitors the harmonic components of the voltage at the point of common coupling using the Goertzel algorithm. The Goertzel algorithm is a kind of discrete Fourier transform. It extracts the magnitude and phase of the desired frequency from the input signal, with a minimum computation. The proposed islanding detection algorithm resolves the NDZ but also the bad effects on the grid power quality due to injecting har- monic components qualified by the interconnection standard. The proposed islanding detection method was verified using PSIM (see www.powersimtech.com) simulations and experimental results.
WHAT IS POWER ELECTRONICS
Power Electronics is a field which combines Power (electric power), Electronics and Control systems. Power engineering deals with the static and rotating power equipment for the generation, transmission and distribution of electric power. Electronics deals with the study of solid state semiconductor power devices and circuits for Power conversion to meet the desired control objectives (to control the output voltage and output power).
Power electronics may be defined as the subject of applications of solid state power semiconductor devices (Thyristors) for the control and conversion of electric power. Power electronics deals with the study and design of Thyristorised power controllers for variety of application like Heat control, Light/Illumination control, and Motor control – AC/DC motor drives used in industries, High voltage power supplies, Vehicle propulsion systems, High voltage direct current (HVDC) transmission.
[attachment=45100]
Abstract:
Islanding refers to a condition of a distributed generator (DG) in that it continues to power a location even though power from the grid is no longer present. This condition can be dangerous to grid workers who may not realize that the load is still powered even though there is no power from the grid. Adverse effects of islanding are low power quality, grid-protection interference, equipment damage, and personnel safety hazards. For these reasons, DG systems must detect an islanding condition and immediately stop producing power; this is referred to as anti-islanding. Islanding detection methods can be categorized into two major approaches: the passive and active methods. The passive methods are based on measurement of the natural effects of islanding. The active methods use intentional transients or harmonic effects. When the power generated by the DG matches the load power consumption, passive methods fail due to the small natural effects of islanding. Therefore, the passive methods have a non detection zone (NDZ).The active method scan reduce the NDZ size. However, these methods reduce the grid power quality. In this paper, a novel anti-islanding method (AIM) is proposed. A single-phase DG using the proposed AIM injects the output current with a little harmonic current into the grid and monitors the harmonic components of the voltage at the point of common coupling using the Goertzel algorithm. The Goertzel algorithm is a kind of discrete Fourier transform. It extracts the magnitude and phase of the desired frequency from the input signal, with a minimum computation. The proposed islanding detection algorithm resolves the NDZ but also the bad effects on the grid power quality due to injecting har- monic components qualified by the interconnection standard. The proposed islanding detection method was verified using PSIM (see www.powersimtech.com) simulations and experimental results.
WHAT IS POWER ELECTRONICS
Power Electronics is a field which combines Power (electric power), Electronics and Control systems. Power engineering deals with the static and rotating power equipment for the generation, transmission and distribution of electric power. Electronics deals with the study of solid state semiconductor power devices and circuits for Power conversion to meet the desired control objectives (to control the output voltage and output power).
Power electronics may be defined as the subject of applications of solid state power semiconductor devices (Thyristors) for the control and conversion of electric power. Power electronics deals with the study and design of Thyristorised power controllers for variety of application like Heat control, Light/Illumination control, and Motor control – AC/DC motor drives used in industries, High voltage power supplies, Vehicle propulsion systems, High voltage direct current (HVDC) transmission.