Comparação de protótipo localizador de faltas com relés comerciais: um estudo para identificação de melhorias

Abstract

Fault location (FL) in transmission lines (TL) plays a strategic role in the operation of electric power systems, as it makes it possible to precisely identify the point of occurrence of disturbances and reduce system restoration time. In this way, accurate FL estimates contribute to efficient service restoration and optimize maintenance activities, thus increasing system reliability. With the objective of monitoring signals and recording disturbances at points of interest, Itaipu Parquetec, with the support of ITAIPU Binacional, developed a device that integrates the functionalities of a Digital Fault Recorder (DFR) and a Phasor Measurement Unit (PMU), resulting in the Disturbance Recorder and Phasor Measurement Unit (RPMF), with its latest update being the addition of an LF module for LTs. Considering the need to test and enhance these updates, this work presents a comparative evaluation of the RPMF’s LF prototype with commercial LF estimators, in order to assess the technological compatibility between the products, as well as to verify whether the proposed multi-method can be applied to more critical LTs without the need for flexibility. To achieve this, real-time simulations were carried out using a Hardware-inthe-loop configuration, in which the RPMF and two intelligent electronic devices (IEDs) were connected in parallel to amplifiers controlled by a Real-Time Digital Simulator (RTDS). The LTused as a model in the tests is part of the Paraguayan power system, selected due to ITAIPU’s interest and aiming for future applications of the LF prototype at the location. In addition to the comparison with the commercial IEDs, the performance of the main LF methods present in the RPMF algorithm was also evaluated, namely: (i) Impedance Method, (ii) Reactance Method, (iii) Simple Takagi, (iv) Negative-Sequence Polarized Takagi, and (v) Zero-Sequence Polarized Takagi. A series of tests was conducted simulating various fault scenarios, including variations in fault type, resistance, incidence angle, and distance to the fault point. The analysis of the results allowed for a comparison between the methods implemented in the RPMF and the other evaluated equipment. The results obtained demonstrate that the RPMF presents satisfactory performance, comparable to the commercial solutions analyzed, and stands out in various scenarios. Furthermore, the analysis of the RPMF methods evidenced potential for multimethod improvement, revealing the possibility of recommendations for strategic adjustments that would increase its accuracy in more critical LTs. Thus, the study reinforces the viability of the RPMF as a promising national solution for LF, distinguishing itself by its performance and flexibility for adaptation to different conditions, while also indicating paths for future developments.