On November 26, 2018, Herch's fiber optic temperature control system for transformer windings was put into operation in Yongle 110KV substation of the China State Power Grid. Yongle Substation is a 110KV integrated automation substation located in Yongle Town, Jingyang County, Shaanxi Province. It was put into operation in October 1992 and transformed into an integrated automation unattended substation in 2006.

Herch's optical fiber temperature control system for transformer winding is used in the 110 KV transformer replaced.