Aprimoramento de soluções de localização de curtos-circuitos em linhas de transmissão.

Abstract

A new single-ended traveling wave (TW)-based fault location method is proposed in this work. It uses the voltage and current signals obtained through the Park’s transformation to estimate the fault distance. For ungrounded short-circuit cases, a correlation function is applied to compute the time delay between the fault-induced incident and reflected waves, whereas the incident direct (aerial)- and zero-mode current components are used for grounded disturbances. The proposed algorithm evaluations are performed through digital simulations. Its validation is carried out by comparisons with the performance of an actual numerical relay equipped with one-terminal TW-based fault location functions, and with the performance of one- and two-ended TW-based fault locators reported in the literature. From the obtained results, the efficiency in locating faults with single-ended measurements by the proposed technique is quite acceptable, even for zero-crossing fault inception angle scenarios and high fault resistances, which are usually reported as limiting factors for this kind of routines. Besides, a significant saving of economic resources are achieved since the use of the proposed algorithm does not require any communication means and their associated devices. In another strand, contributions on sensitivity analysis of five EMTP-based coupling capacitive voltage transformers (CCVT) digital models for protection studies are presented, in which their frequency response changing due to modeling errors or CCVT aging are shown, including the phase response, which is not often reported in the literature. Additionally, an original study of statistical analysis using the obtained fault location estimated errors is performed, attesting that the total error points can be approximated by a function with normal probability distribution.