Assessment of the Impact of Joint Bays on the Ampacity of High-Voltage Cable Circuits

Improvements in the cost and availability of computational power in recent years has led to numerical techniques such as finite-element analysis (FEA) becoming viable for cable-rating calculations. This analysis has previously been completed for the case of directly buried and force-cooled cable circuits, but without direct consideration of the joint bay. This paper presents methods by which conductor temperature profiles within joint bays may be obtained through the use of FEA. Results are presented for a number of joint bay configurations common to the U.K. for naturally and force-cooled installations. Implications of the results on circuit-rating practice are discussed and the benefits of using tools, such as FEA, are considered versus other existing methods.