Determination of critical span in real time using proper orthogonal decomposition

In a power delivery system, excessive loads may lead to high temperature of power transmission lines. The extent of aging is proportional to the severity of the thermal overload. How to evaluate aging is an important issue for electric power systems. A critical span refers to a span where the highest conductor temperature occurs in transmission lines and thereby limits how much power can be delivered. In order to monitor real-time temperature of an overhead transmission network, this paper develops a method to simulate a dynamic model for conductor temperature distribution of transmission lines. Proper orthogonal decomposition (POD) is a widely used technique to simulate a spatio-temporal model. For high-dimensional data, POD is an efficient method to reduce the complexity of modeling. Furthermore, an extension of POD - the gappy POD - is used in this study to determine the critical spans so as to reconstruct the conductor temperature distributions of all spans. The simulation results show that the proposed method provides an efficient way of estimating transmission conductor temperature with high accuracy. The average mean square error is less than 10^-4. Through building a transmission conductor temperature model, the critical span of transmission lines are determined so that effective management and scheduling in real time for power delivery systems can be achieved.