A simplified mathematical procedure for determining the transient temperature rise of cable systems [includes discussion]

The transient temperature rise of a cable system under a constant load, that is, the manner in which the temperature of the conductor rises with time after the constant load is applied, is a matter of considerable interest to cable engineers, since it may serve as a basis for short time ratings, and for the determination of the temperature variations with a varying load. Although these determinations are most readily made by means of an analogue computer nevertheless there is need for rnathematical methods of determining this basic constant-load-temperature transient. This paper presents a simplified mathematical procedure which it is believed suffers only from the actual procedure, apart from theory, being extremely intricate and laborious. In this respect only is it limited to a degree. While a portion of the procedure is admittedly somewhat laborious, the computations re quired in this part involving the application of vector algebra are such that they may be done by an engineering assistant who need not necessarily be familiar with cable engineering.