Medium voltage line parameter estimation using synchrophasor data: a step towards dynamic line rating

In an active distribution grid with high renewable penetration, thermal rating of critical lines could be a major constraint for bulk power routing during high generation periods. The loading of the lines are generally fixed based on electrical characteristics, physical arrangement and ambient conditions of the conductor. Dynamic Line Rating establishes dynamic loading values defined for a period of time based on line temperature and ambient environmental conditions. The authors have proposed a novel approach for estimating the line temperature without heat equation or thermodynamic approaches. Accurate estimates of real-time resistance of the line could hold the key to determine the temperature of the conductors. In the past, algorithms have been developed to estimate the line parameters of transmission lines. In this paper, an attempt has been made to analyze the applicability of a parameter estimation method to estimate the temperature of a medium voltage line. Case of overhead-line and underground cable were considered for analysis. Accuracy of the parameter estimator was investigated by implementing it in a simulated medium voltage distribution grid in presence of practical real-field challenges like ratio and phase errors of current and voltage transformers. Effects of random errors associated with measurement on the accuracy parameter estimation are also studied.