مدل سازي مايكروگريد جزيره اي مبتني بر مبدل هاي استاتيك و بررسي رفتار ديناميكي آن

چكيده انگليسي :

Modeling of an Islanded Converter Based Microgrid And Analysis of Its Dynamics Seyed Shahab Tabatabaee Sh tabatabaee@ec iut ac ir Date of Submission 2009 5 10 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan Iran 84156 83111 Degree M Sc Language FarsiSupervisors name Hamid Reza Karshenas karshen@cc iut ac irAbstract Nowadays Distributed Energy Resources DERs are used extensively They have eliminated lots ofpower system problems However high penetration of DERs can cause other problems like increasing powersystem complexities and malfunction of protection schemes Traditional approaches for integrating DERsfocus on the impacts on grid performance of one two or a relatively small number of DERs Also theseapproaches concern ensuring that interconnected DERs will shut down automatically if problems arise on thegrid By contrast the Microgrid concept represents an entirely new approach to integrating DERs AMicrogrid would be designed to seamlessly separate or island from the grid and reconnect to the grid onceits problems are resolved The Microgrid concept assumes a cluster of loads and Distributed Energy Resources operating as asingle controllable system that provides both power and heat to its local area In this thesis variousMicrogrids with different structures that have been implemented in the world are briefly described One ofthese Microgrids is selected as the test grid of this thesis Operation of Microgrids consisting of converterbased DERs is also analyzed and their modes of operation is discussed Properties of a grid connectedMicrogrid are described Specifically it is explained why energy resources in a grid connected Microgridsare preferred to operate in PQ mode Time domain simulations of a grid connected Microgrid are used toanalyze the operation of DERs controllers An important mode of Microgrid is islanded mode This mode acts as a stimulus to reliabilityincreasing In this mode control system has some new responsibilities These responsibilities are voltagecontrol frequency control and load sharing The concept of load sharing and frequency synchronization isexplained Two droop characteristics used to share the active reactive power between DERs are describedand compared and the requirements for implementing each method are discussed Time domain simulationsare used to verify the operation of islanded Microgrids with different droop characteristics This thesis isconcerned with the modeling and analysis of islanded Microgrids and the effect of different parameters ontheir performance The small signal analysis of an islanded converter based Microgrid is presented In doingso the Microgrid is divided to some sections and different sections of it including static converter and filter controllers and the network are modeled separately Finally these models are connected together and theaggregated model of the Microgrid is obtained By introducing some perturbation in the small signal model it is shown that the results are very close to the time domain simulations thus verifying the frequency domainmodeling With this verified model of Microgrid eigen value analyses are presented The effect of different variables on the operation of Microgrids is examined Specifically the slope ofdroop characteristic X R ratio of lines the length of lines and the location of sources are studied and theireffect on the operation of Microgrid is shown These studies are based on the results of eigen value analysesand time domain simulation of the Microgrid Key Words Distributed Energy Resources Microgrid static converter load sharing conventional droopcharacteristic inverse droop characteristic

طباطبايي، شهاب

مدل سازي مايكروگريد جزيره اي مبتني بر مبدل هاي استاتيك و بررسي رفتار ديناميكي آن

منابع انرژي پراكنده , تقسيم بار , مشخصه افتي مرسوم , مشخصه افتي معكوس