I'm finishing my PhD which was in developing a new method for modelling controllable devices in LF studies. The method is based on constructing an external (with respect to the LF problem) criterion function in such a way that the root of this function corresponds to the correct solution. So, the LF routine is unaltered and I use runpf() as a subroutine. I have completed the derivations and have tested the codes using MatPower. Seeing as there are quite a lot of questions about this functionality I have decide that I would like to make the codes available to others. ?The modelling is developed for transformers (OLTC, PAR, QBT), 1st gen FACT (Series and Shunt compensation) and for 2nd gen.FACTS (STATCOM, SSSC, UPFC, IPFC, GUPFC). So, does anybody think there is anything special to take into consideration before I upload? Also, a question for Ray, I previously made a pull req on GitHub with tap changers and phase shifters and I was wondering if that was ok? Because maybe I'd do it similarly this time. regards, Gorazd.