طراحي سيستمي و تحليل ديناميكي نيروگاه هاي فتوولتائيك متصل به شبكه

چكيده انگليسي :

98 System Design and Dynamic Analysis of Utility Scale PV Energy Systems Zahra Moradi Shahrbabak z moradishahrbabak@ec iut ac ir Date of Submission August 2012 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisors Ahmadreza Tabesh a tabesh@cc iut ac ir and Gholamreza Yousefi yousefi@cc iut ac ir Abstract Advances in silicon base photovoltaic cells and incentive policies for deployment of renewable energy systems have rapidly increased the installed capacity of photovoltaic PV energy systems during the last decade Utility scale PV power plants in the range of tens of MW have been installed and currently operational all over the world Upgrading the size of PV power plants to hundreds of MW requires establishing and complying specific grid codes to maintain the integrity and security of the modern power systems including renewable energy systems High cost of investments and non dispatchable features of PV energy systems introduce new challenges in topology design and grid integration of these systems compared to the conventional power plants Various topologies including centeralised string multi string and modular topologies have been suggested for utility scale PV plants which offer different investment costs Levelized Cost Of Energy LCOE index has been commonly used to compare the cost of energy in different topologies for PV power plants The LCOE index represents the total life cycle cost of a system including investment and maintenance costs per total amount of generated energy over the system physical lifetime This thesis in the first part deals with system design of a utility scale PV power plant that is identifying the best topology and the optimum size of PV strings and inverters for a large scale PV plant The thesis introduces an improved cost index so called Effective LCOE ELCOE which calculates the cost per unit of energy This index estimates the total amount of generated energy by considering the probability of operation of the PV system To investigate the capability of the improved index both LCOE and ELCOE have been calculated and compared for various PV topologies using a case study It will be shown that ELCOE compares PV plant topologies more accurately from techno economical point of view Using this index the multi string topology is identified as the best topology for implementation of utility scale PV plants The thesis also presents an effective cost criterion which mathematically formulates the cost of energy in a PV plant based on different size of inverters This criterion is used to develop an algorithm to find the best size of inverters based on cost and voltage data of the commercially available solar inverters The second part investigates a method for dynamic analysis of a grid connected utility scale PV plant The dynamics of an electronically interfaced PV energy system stem from multiple feedback loops for the control of real reactive powers injected to the grid The PV system dynamics are integral parts of the power system dynamics and due to high penetration level of utility scale PV plants and fluctuation of generated solar power during a day it is necessary that the system remains stable regardless of changes in the generated power of the PV system The thesis presents a method for small signal modeling and frequency domain analysis of a power system including a PV power plant The accuracy of the method is investigated via comparing the frequency domain analysis results with time domain simulation results of a study system Keywords Photovoltaic energy systems PV plants PV Topology design Small signal dynamics Techno economical analysis

مرادي شهربابك، زهرا

طراحي سيستمي و تحليل ديناميكي نيروگاه هاي فتوولتائيك متصل به شبكه

بازده , ساختارهاي اينورتري , ضريب نفوذ , قابليت اطمينان , مدلسازي ديناميكي , مدل ماركوف , نيروگاه هاي خورشيدي فتوولتائيك , هزينه انرژي تراز شده