Uncertain Impedances Propagation in Power Flow by Polynomial Chaos Expansion

Distribution networks are integrating a growing number of flexible consumers and distributed generation, opening the possibility for their management. However, instrumentation is very scarce in distribution areas. As lines have a very long service life, their impedances cannot be assumed to be perfectly known. This study therefore proposes to introduce into the power flow equations a source of uncertainty arising from the impedances values. This stochastic power flow is solved using Polynomial Chaos Expansion. The accuracy of this method is confirmed on a case study, along with its numerical efficiency. It is also revealed to be capable of adapting to very high impedance variances, as well as to asymmetric distributions with discontinuities.