Fig. 1
![Fig. 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs43067-020-00019-2/MediaObjects/43067_2020_19_Fig1_HTML.png)
a Single-line diagram of UPFC connected between bus-i and bus-j. b Single-line diagram of OUPFC connected between bus-i and bus-j
a Single-line diagram of UPFC connected between bus-i and bus-j. b Single-line diagram of OUPFC connected between bus-i and bus-j