Estimating the remaining useful life of power grid transmission lines using synchrophasor data

Abstract

This paper addresses the use of traditional PHM techniques for estimating the remaining useful life (RUL) of a transmission line in a typical power grid. The sensor of interest is the Phasor Measurement Unit (PMU) which provides sampled data in the form of a synchrophasor. A Synchrophasor is a GPS based time stamped measurement of voltage and current at different physical locations on the grid. It is the fact that the measurements are time stamped to a common clock that allows one to obtain the absolute phase difference between measurements at different points in the grid. It is this phase difference that determines the health of the grid. Too large of a phase difference can result in voltage collapse and a subsequent blackout. In this paper, we propose a model for describing the aforementioned phase difference and obtain estimates of the model parameters. We subsequently use our model to formulate an equation that estimates the RUL of a given transmission line. This technique is applied to three different cases of phase difference that one might observe on an actual power grid, with estimates of the RUL presented for each case.