Desenvolvimento de um sistema de monitoramento online de descargas parciais para transformadores de potência

Abstract

Serious failures in power transformers are usually driven by problems in the insulation structures, whether internal to the tank or in the bushings, and constitute one of the most critical occurrences of the power system. Thus, the evaluation of the insulation condition of a transformer is of great importance for the operational efficiency of the transmission and distribution of electrical energy. However, as insulation systems are complex, many challenges are seen in terms of measurement systems and modes of analysis of critical parameters such as partial discharges (PDs), which are recognized as a phenomenon that carries relevant information regarding the health of a high voltage equipment. In this context, this dissertation addresses the development of an online monitoring system for partial discharges for power transformers. The system applies the electrical method to detect the discharge pulses through capacitive coupling in condenser bushings and is integrated by a proprietary software for data processing and communication with supervisory systems through the DNP 3 protocol. The robustness of the developed system and the guarantee of integrity of the monitored equipment, as well as the ability to correlate data to track the condition of the asset, were verified by laboratory tests and real applications in substations. In the latter case, the results were explored to show how information from a PD can be interpreted in practical situations to analyze the conditions of the asset and assist in defining diagnoses.