Fuzzy logic supervision and control of distributed generators

The decentralised production connected to electrical network has been a research theme quite developed during the last years. Indeed, several factors are responsible of such rise, technological progress in the dispersed generation fields, government economic incentives for renewable energies and finally, surely the most important factor, the deregulation permitting the possibility to sell energy provided by distributed generators (DG) connected to the transport or distribution existing networks [1]. The more common units are small-scale generation units connected on the low-voltage (LV) networks. But high penetration of that distributed energy resources (DER) may influence the operation of the network The current structure of the network is not adapted to a high insertion of DER, so the technical problems have to be identified and analysed, and studies have to be lead to improve the quality and the stability of the network using DER. This study deals with DG participations to the ancillary services and to the network operation. DR can participate to increase reliability and stability of the network, providing power closer to the consumption and they can participate to voltage control [2] [3J. This work proposes connexion of prime sources to the grid via a power electronic level. By using the inverter, it is possible to control voltage with the reactive power injected. To create a flexible and evolutive control of such system, fuzzy logic is well adapted. In the case of a high penetration of DER the control device has to be calculated considering the network states. Fuzzy logic supervision is able to adapt these control parameters depending on the error states and on its dynamic variations, regardless of the network states in terms of currents or power flows. This kind of control will permit a better stability in dynamic simulation. In this context a powerful control system for the system DER-inverter must be developed. This paper proposes a power and voltage contro- scheme for DG using a fuzzy logic supervisor. The work is divided in three parts; the first one is about the association DG and inverter modelling and control, followed by the development of the fuzzy supervisor. Finally test and results are leaded to prove the efficiency of such a control.