SOME STUDIES ON PERFORMANCE IMPROVEMENTS OF COMBINED CYCLE POWER PLANTS

Abstract

Worldwide power industry structure is changing to market economy to ensure commercial availability. The resource are allocated for operation and maintenance from commercial consideration rather than technical alone, necessitating introduction of a commercial approach for the analysis of reliability, efficiency, installation and operating cost for thermal power plants. These requirements suggest the need for development of mathematical model for monitoring the performance of system in the form of a single numerical composite index capable of incorporating all design and operating parameters affecting the plant performance. In the present work a simple, numerically efficient model based on Graph Theoretic Analysis (GTA) is used to develop a single composite performance index on the basis of efficiency and reliability for combined and cogeneration cycle power plants. For Graph Theoretic Analysis (GTA), combined and cogeneration cycle power plant are divided into sub-systems and various interconnections between sub-systems and parameters affecting them are presented in System Structure Graph (SSG). The developed SSG for performance, reliability and efficiency, represented by a matrix is used for detailed evaluation and analysis of the both combined and cogeneration cycle power plants using computational tool. Reliability of different subsystems is used to develop a real-time reliability index (RTRI) for the power plants. Similarly, using operating efficiency data of various sub-systems, real-time efficiency index (RTEI) is also developed. With the help of RTRI and RTEI, a composite index for efficiency and reliability (CIER) has been calculated which is helpful in decision making for system selection and monitoring the performance of the power plant in real time. Design parameters and their interdependencies are quantified iteratively for calculating RTRI and RTEI and results obtained are found to be in good agreement with industrial data. Initial guess for the quantification is obtained from the thermodynamic inference. Exergy analysis of cogeneration cycle power plant has also been carried out for the identification and quantification of PDF Created with deskPDF PDF Writer - Trial :: http://www.docudesk.com design parameters for efficiency at sub-system level. Practical implementation of the proposed methodology in a systematic manner is helpful for power generation industry to identify, categorize, analyse and evaluate parameters responsible for plant reliability and efficiency.