his paper reflects the authors' experience in conductor thermal part (temperature) and mechanical part (sag and clearance) estimation in real Latvian PS conditions using IEEE, CIGRE, Girshin and classical mechanics methods. Both theoretical and practical results of the research are discussed. Theoretical calculations based on real Phasor Measurement Unit (PMU) measurements of 330 kV line and environmental data collected from meteo-websites have shown that deviation is low in conductor thermal calculation methods. The Dynamic Line Rating (DLR) measurements are improved with the PMU data, which permit accurate line current data with GPS timestamps. The authors have calculated the conditions of conductor thermal dynamics at a step of one second; such accuracy together with environmental data can provide an excess of maximum line capacity without harming the conductor life cycle. © 2016 Power Systems Computation Conference.