Assessment of the Main Phasor-Based Power Transformer Differential Protection Elements
Rodrigo Prado de Medeiros1; Flavio Bezerra Costa1; Marcos Antonio Dias de Almeida1
1 UFRN
doi:10.20906/CPS/SBSE2016-0404
Resumo
With the advance of the digital technology, the basic principles of the power transformer differential protection have been implemented in logical schemes in the modern numerical differential relays. Moreover, the power transformer differential protection also incorporated the usage of additional protection functions, such as harmonic restraint, harmonic blocking, and negative-sequence current differential elements, improving the discrimination between internal faults and other events. This paper aims to present an analysis about the operation of the main phasor-based differential protection functions during the occurrence of relevant disturbances involving a power transformer modeled in ATP software. By means of the analyze of the differential currents obtained in the different records, the behavior of the several protection functions and the importance of each one were highlighted in order to ensure a robust, reliable and fast protection.
Palavras-chave: Power transformer; Differential protection; Harmonic restraint; Harmonic blocking; Negative-sequence