The secondary busbar structure,layout and operation status dictate the operation status of the thermal phosphorus furnace unit.Taking the up-set case process parameters of the phosphorus furnace transformer of Plant 2 as an example,the causes of the incident and the issues identified in the treat-ment process are analyzed.It is proposed that in the process of incident investigation,theory should be combined with practice,comprehensive considera-tion,comprehensive analysis,and advanced experience should be leveraged to continuously achieve breakthroughs and innovations in core technologies,and further supplement and improve the basic theory of thermal phosphorus production technology.