PMU-Based Cable Temperature Monitoring and Thermal Assessment for Dynamic Line Rating

The aim of this paper is to present a novel phasor measurement unit (PMU) data-based cable temperature monitoring method with an intended application towards facilitating dynamic line rating. First part of the paper presents the method to estimate and track the temperature of a 3-phase cable segment. The benefit of this temperature monitoring method is that no additional temperature measurement sensors are required to be placed along the cable. The method is based on a novel algorithm which gives accurate resistance estimates for 3-phase cable segments even in the presence of random and bias errors in the grid measurements. The performance of the method is demonstrated by utilizing data from PMUs in a distribution grid. The results from the grid data show that the method is capable of monitoring the cable temperature up to an accuracy of ±5 °C. The later part of the paper presents a system to utilize the temperature estimates given by the monitoring method to predict the dynamic thermal state of the cable for forecasted power-flow scenarios. This is demonstrated by using the available temperature estimates to initialize and solve the system of equations given by the thermoelectric equivalent (TEE) model of the cable.