Research for dynamic increasing transmission capacity

The Dynamic Line Rating (DLR) system can increase transmission capacity of overhead line dynamically. The system is composed of sampling terminals installed on dead-end configuration of a line and one control instrument equipped in dispatch center. The data between the sampling terminals and the control instrument is transmitted through GPRS/GSM. Then three major limitations governing the line rating limits were analyzed and stated. This paper analyzed the force balance for overhead line concerned wind speeds and wind direction in a deflection plane. On this basis, a mechanics analysis model of line’s tension and sags was established. Analyzed the advantages and drawbacks of some mathematic model used to calculate transmission capacity. In order that the DLR system received the optimum dynamic capacity curve, combined the WM and TS model. Finally, the necessity and significance to use DLR in power grid are presented.