Microturbine based distributed generator in smart grid application

Abstract

Microturbines (MTs) are currently being deployed as small scale on-site distributed generators for microgrids and smart grids. This calls for extensive off-line and real-time research for analyzing the load following performance of MTs under islanded and grid-connected modes of operation at distribution voltage level. This paper presents development and simulation of MT models to analyze its load following performance with general as well as critical priority loads. Load following analysis of the models are carried out through Matlab simulations for both standalone and grid-integrated modes of operations. Two MT models are considered for performance analysis. MT Model-1 comprises speed governor, acceleration control and temperature control blocks. It is assumed that MT is operating under normal operating conditions (neglecting its fast dynamics). Speed control operates on the speed error formed between a reference speed and rotor speed. Speed control is usually modelled by using a lead-lag transfer function or by a PID controller. MT Model-2 is based on the standard GAST model. The real power control is described as conventional PI-control function. The MTgenerator unit consists of the MT coupled to a synchronous generator. The unit is integrated to the utility distribution system at the point of common coupling (PCC). It can be connected/disconnected to distribution system by operating the PCC circuit breaker.