Methodology for Protection Performance Evaluation on Power Transmission Networks

Abstract

An innovative methodology for protection performance evaluation on transmission networks is presented in this paper. It was developed to overcome difficulties faced by the Brazilian utility Companhia Hidro Eletrica do Sao Francisco (CHESF) during the preparation of short-circuit reports that must be sent to regulatory organizations whenever transmission-line faults occur. In the proposed methodology, a combination of several algorithms is used to extract from oscillographic records relevant information about short circuits and performance of protection functions. Aiming toward practical applications in CHESF, a software named disturbance analysis and protection performance evaluation has been developed in order to execute the proposed methodology functions, providing reports about the short-circuit characteristics and protection operation. To validate the proposed methodology, digital fault simulations in the Alternative Transients Program (ATP) and in Computer-Aided Protection Engineering (CAPE) software were carried out. Furthermore, real-world fault cases were also analyzed by assessing actual oscillographic fault records provided by CHESF. The obtained results show that the proposed methodology is reliable and quite useful for short-circuit analysis and protection performance evaluation procedures.