Comparison between IEEE and CIGRE ampacity standards

Bolh l,E,€:.E. and CIGRt havc published industry standards Cor calculating thc ampaciiy of overhrad conductors. Although these two standards use the same basic heal balance concept, they usc difSercnt appriiaches to calculate ainpacity ratings. As a result of thcse diSCercnces. thc ampacity rating cak!ukdted by each mcthod may vary by almost 10% dcpcnding on the environmenlal conditions being considered. This paper looks at thc diSSerent approaches used to calculate individual heal bdldncc terms, at lhe ovcrall impacl oSlhesc tcrms on the ampacity rating. and at Lhc scnsitivity oi“ thesc approaches to varinus input parameters. The uscr of these standzirds should he aware of thesc variations in calculated ratings and, i f they consider these variations significant. thz uscr inectls lo sclcct a singlc approach Cor rating thcir lines based on thcir undcrstanding oC these difScrcnt approaches and of thc puhlishcd cxpcrimcntdl research supporting each method.