A q component‐based adaptive protection coordination optimisation using overcurrent relays in coordination with fuses for hybrid microgrid

Abstract

In a hybrid microgrid, the overcurrent relays (OCRs) must sense the changes in the fault currents while the microgrid switches from the grid-connected to the islanded mode of operation. Further, for the different types of distributed generator (DG), such as photovoltaic (PV), wind turbines of types I, III, and IV, the variation in fault currents must also be detected by the relays. This leads to delay and inappropriate coordination in conventional protection schemes. To minimise the impact of inappropriate coordination in this study, an adaptive protection scheme with optimal settings is proposed for phase and earth faults detection. It also takes care of different nature of DGs, all feasible operating modes of hybrid microgrid with only quadrature (q) component of fault current while zero component is used to differentiate between earth and phase faults. Also, only q component-based proposed technique optimises the coordination time (CT) of fuses as a backup to primary and backup relays with newly proposed CT interval constraints. A differential evolutionary algorithm is proposed for determination of optimal settings for the directional OCRs.