5. Define the verification method. Second part: detection of steady state

While the European family of standards says nothing about how to detect the established regime, fascicule X15-140 proposes two methods: a graphical one and a statistical one, the latter having several advantages.

• Based on tests of equality of mean and variance, it is relevant when sufficient samples are available and the recording time is greater than one period of regulation oscillation.

• Easily automated, it can detect a stable phase in real time or a posteriori.