Development of a grid connected solar photovoltaic system

Abstract

This study and development are focused about an integration of a solar photovoltaic (PV) system to an existing power plant located in Colombo Sri Lanka. The combined cycle power plant related to the project consists of many easily identifiable resources for the development of a solar project. Survey to find out available resources, ways of integrating the selected resources to optimize the project outcome, best way to utilize the solar energy and finding out the feasibility of implementing the project are the objective behind the project development. The project identifies a grid connected solar PV system with a single axis tracking as the best way to integrate solar PV energy to an existing power plant. The areas of study and design are related to solar panels and the structural frame work, sun tracking system, tracker drive mechanism, power conversion and power evacuation system. The project components selection criteria developed in this project are based on the preliminary studies and surveys. Comparison made for deferent types of solar cells based on their reliability, cost & efficiency. Also surveys were done about gains, regulations, quality checks, safety and environmental aspects related to project components. Upon finalizing the basic project configuration, sizing of the systems carried out in a logical criterion prior to the detailed design stages. Comprehensive design carried out for the control module and drive mechanism of solar tracker which demonstrates the flexibility of existing plant control system. Design of structural framework is used to find cost components relevant to the balance of system and to find out the impact of loading the building roof with solar PV components. Cost benefit analysis carried out against three different options of energy dispatch to meet the conclusions. As an outcome following conclusions have been met, • By effective utilization of existing resources available at a power plant simple pay back (SPB) period of a solar PV system of 106 k W capacity could be brought down to 9-10 years . • A single axis tracking system could further reduce the SPB period of a solar PV system. • It is more beneficial to export solar PV energy separately to the grid during the cases where thermal energy production cost is cheaper than Rs.20/= to further bring down SPB period. This is possible by introducing a switching signal from DCS for smooth change over between separate power feeding and station power feeding based on online energy unit cost comparison. • Design, construction and commissioning of Solar PV system with a thermal power plant at initial stages in parallel with main project could avoid wastages of resources. The concepts and design criteria used at different phases of this project development could be useful for direct application or with appropriate modifications to incorporate with solar PV project developments.