“平夷” is just a name of a county. It is a proper noun。
In Yong Jia 5th Year of Jin (AD 311), a part of tthe Zang Ke (牂柯) Region was separated and became a new Region named Ping Yi (平夷).
The seat of its local government is in Ping Yi County, which located in today's southwestern part to Ren Huai County, Gui Zhou Province.
Two counties are under the jurisdiction of Ping Yi Region: the Ping Yi County and the Bi County