CLOSE UP OPERATION OF DISTRIBUTION CABLES CONSIDERING THERMAL CAPACITY LIMITS OF JOINTS

Abstract

In this thesis, a navel model of a thermal relay for cable thermal protection is introduced. This model is developed for microprocessor-based relay implementation. The time-current characteristics provided using this model can be adjusted to match the thermal characteristics of a cable containing a joint, taking the surrounding temperature into considerations. The permissible time-current curves of this cable were obtained via measuring the heat build-up curves. Effect of surrounding temperature on these time-current curves is tested experimentally. Also, effect of temperature measuring location along the cable is high lighted. Results of the experimentally carried out tests are discussed. Curve modeling procedure is presented and a proposed design of a microprocessor- based relay using the developed model is given