Open AccessPrimary control level of parallel distributed energy resources converters in system of multiple interconnected autonomous microgrids within self‐healing networks
Author(s) -
Shahnia Farhad,
Chandrasena Ruwan P.S.,
Rajakaruna Sumedha,
Ghosh Arindam
Publication year - 2014
Publication title -
iet generation, transmission and distribution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 110
eISSN - 1751-8695
pISSN - 1751-8687
DOI - 10.1049/iet-gtd.2013.0126
Subject(s) - microgrid , voltage droop , converters , distributed generation , control theory (sociology) , controller (irrigation) , control engineering , decentralised system , computer science , linear quadratic regulator , distributed computing , engineering , control (management) , voltage , voltage regulator , renewable energy , electrical engineering , agronomy , artificial intelligence , biology
To minimise the number of load sheddings in a microgrid (MG) during autonomous operation, islanded neighbour MGs can be interconnected if they are on a self‐healing network and an extra generation capacity is available in the distributed energy resources (DER) of one of the MGs. In this way, the total load in the system of interconnected MGs can be shared by all the DERs within those MGs. However, for this purpose, carefully designed self‐healing and supply restoration control algorithm, protection systems and communication infrastructure are required at the network and MG levels. In this study, first, a hierarchical control structure is discussed for interconnecting the neighbour autonomous MGs where the introduced primary control level is the main focus of this study. Through the developed primary control level, this study demonstrates how the parallel DERs in the system of multiple interconnected autonomous MGs can properly share the load of the system. This controller is designed such that the converter‐interfaced DERs operate in a voltage‐controlled mode following a decentralised power sharing algorithm based on droop control. DER converters are controlled based on a per‐phase technique instead of a conventional direct‐quadratic transformation technique. In addition, linear quadratic regulator‐based state feedback controllers, which are more stable than conventional proportional integrator controllers, are utilised to prevent instability and weak dynamic performances of the DERs when autonomous MGs are interconnected. The efficacy of the primary control level of the DERs in the system of multiple interconnected autonomous MGs is validated through the PSCAD/EMTDC simulations considering detailed dynamic models of DERs and converters.