EPE Association: EPE 2007 - Subtopic 13-2 - LS: Distributed Generation

EPE 2007 - Subtopic 13-2 - LS: Distributed Generation
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 13: 'Electrical energy generating systems, renewable energy systems' > EPE 2007 - Subtopic 13-2 - LS: Distributed Generation

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   Influence Analysis of the effects of an Inductive-Resistive Weak Grid over L and LCL Filter Current Hysteresis Controllers
By BUENO Emilio; HUERTA Francisco; COBRECES Santiago; RODRIGUEZ Francisco J. [View]
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Abstract: The objective of this paper is to analyse the influence of a non-ideal grid over hysteresis controllers of converters connected to the grid through both L and LCL filters. The paper will describe the different possible configurations in both cases, analysing the effect of a general R-L grid. Limit values for both grid inductance and resistance are given for the L structure. In the case of LCL connection, the analysis will overview important issues such as active damping, and switching behaviour giving limits to stability as a function of grid impedance value.

   Optimized destabilizing islanding protection scheme for grid-tied inverters insensitive to short term network disturbances
By BRÃœNDLINGER Roland; MAYR Christoph [View]
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Abstract: When interconnecting inverter based distributed generation (DG) systems to the distribution grid, an islanding detection is essential to avoid substantial safety and performance implications. Many anti-islanding methods currently used for grid connected inverters have weaknesses as high sensitivity resulting in spurious tripping or distortion of the output currents, particularly in multi-inverter installations. The main objective of the work presented here is to develop a new destabilising anti-islanding detection scheme, which combines an active frequency shift technique using positive feedback with a Rate of Change of Frequency (RoCoF) detector and an innovative control algorithm. It enables to discriminate between short term frequency disturbances on the network and transition to or operation of an undesirable island. The optimized approach presented here reliably avoids unintentional islanding and furthermore exhibits optimal performance during frequency fluctuations in the network. It will be demonstrated that the new scheme has better performance than existing ones by using a SIMULINK model.

   Parallel Operation of Uninterruptible Power Supply Systems in MicroGrids
By GUERRERO Josep [View]
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Abstract: In this paper, a control scheme applied to distributed UPSs forming a microgrid is proposed. The control architecture consists of two levels of hierarchy: 1) the P/Q droop control method of every UPS unit and 2) the management of the microgrid through the control of the setpoints of the units, and the connection or disconnection to the utility mains.

EPE 2007 - Subtopic 13-2 - LS: Distributed Generation
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 13: 'Electrical energy generating systems, renewable energy systems' > EPE 2007 - Subtopic 13-2 - LS: Distributed Generation
	[return to parent folder]

	Influence Analysis of the effects of an Inductive-Resistive Weak Grid over L and LCL Filter Current Hysteresis Controllers By BUENO Emilio; HUERTA Francisco; COBRECES Santiago; RODRIGUEZ Francisco J.	[View] [Download]
Abstract: The objective of this paper is to analyse the influence of a non-ideal grid over hysteresis controllers of converters connected to the grid through both L and LCL filters. The paper will describe the different possible configurations in both cases, analysing the effect of a general R-L grid. Limit values for both grid inductance and resistance are given for the L structure. In the case of LCL connection, the analysis will overview important issues such as active damping, and switching behaviour giving limits to stability as a function of grid impedance value.

	Optimized destabilizing islanding protection scheme for grid-tied inverters insensitive to short term network disturbances By BRÃœNDLINGER Roland; MAYR Christoph	[View] [Download]
Abstract: When interconnecting inverter based distributed generation (DG) systems to the distribution grid, an islanding detection is essential to avoid substantial safety and performance implications. Many anti-islanding methods currently used for grid connected inverters have weaknesses as high sensitivity resulting in spurious tripping or distortion of the output currents, particularly in multi-inverter installations. The main objective of the work presented here is to develop a new destabilising anti-islanding detection scheme, which combines an active frequency shift technique using positive feedback with a Rate of Change of Frequency (RoCoF) detector and an innovative control algorithm. It enables to discriminate between short term frequency disturbances on the network and transition to or operation of an undesirable island. The optimized approach presented here reliably avoids unintentional islanding and furthermore exhibits optimal performance during frequency fluctuations in the network. It will be demonstrated that the new scheme has better performance than existing ones by using a SIMULINK model.

	Parallel Operation of Uninterruptible Power Supply Systems in MicroGrids By GUERRERO Josep	[View] [Download]
Abstract: In this paper, a control scheme applied to distributed UPSs forming a microgrid is proposed. The control architecture consists of two levels of hierarchy: 1) the P/Q droop control method of every UPS unit and 2) the management of the microgrid through the control of the setpoints of the units, and the connection or disconnection to the utility mains.