Guest Editorial

Abstract

This is an IET Renewable Power Generation Special Section from the 3rd IET Renewable Power Generation Conference that was held in Naples. There was a wide range of topics among which were wind (turbines, offshore wind farms),photovoltaic generation, distribution power systems including power conversion, management of energy by means of demand side management and energy storage taking into consideration power markets. More than 120 papers were included in the conference's technical programme, and the topics covered a broad spectrum within the field of renewable power generation. A selection of papers presented at the Naples conference were considered appreciable by the Conference Session Chairs and invited to submit to the IET Renewable Power Generation journal. After extensive peer review, two significant papers were accepted for publication by the Editor-in-Chief and the Associate Editor. The accepted papers cover both generation by renewable sources and distribution of the energy treating, in particular, aspects related to the integration of renewable sources in the grid and the control and management of a distributed generation network. K. Musasa, M. N. Gitau and R. C. Bansal, in their paper “Dynamic analysis of DC-DC converter internal to an offshore wind farm”, have analysed the automatic generation control (AGC) problem and considered it in interconnected power systems with doubly-fed induction generator (DFIG)-based wind turbines. A non-linear least squares support vector machines (LS-SVM)-based AGC regulator is proposed; this is trained from an off-line data set obtained from designing and implementing the robust controller to power a system under diverse operating conditions and area load changes. An investigation of time response plots reveal that the designed LS-SVM-based AGC regulator shows promising performance for power systems with governor dead-band non-linearity when compared to that obtained with multi-layer perceptron neural networks and conventional PI-based AGC regulators for a wide range of parametric uncertainties and area load disturbances occurring in the area of the power system. In their paper, M. Cresta, F. M. Gatta, A. Geri, M. Maccioni, A. Mantineo and M. Paulucci analyse possible strategies for the control and management of an LV network with distributed generation connected at LV (consisting in photovoltaic power plants equipped with the last generation of inverters) and electric vehicles charging stations (EVCSs). Various possible scenarios have been studied: the LV network as actually operated; the network operated with the EVCS and the network operated with the EVCS and the NAS storage system. The evolution of voltage levels at the LV busbar, of power-factors at the secondary substation and of energy losses in the LV network have been calculated. By analysing the results, it was found that the installation of the EVCS itself does not present any criticality for the considered distribution network. A proposed optimal power flow detects optimal strategies for the management of reactive power flow supplied by the PV inverter and for the control of charge/discharge cycles of the NAS. From an economic point of view, the installation of the NAS appears to be unjustifiable because of both the high investment cost and the increase in operating costs (due to the additional energy losses). Lastly, the “demand response” practice, applied to “secondary substation” customers does not provide significant benefits on the network operation. However, this practice may generally constitute a convenient and effective solution for the implementation of the “load shifting” along a daily load diagram.