SPD in illumination system of HV air insulated substation Anton Kosorukov, Pavel Karpov, Nataliya Kutuzova, Svetlana Pashicheva and Vasiliy Titkov E3S Web Conf., 164 (2020) 03020 Published online: 05 May 2020 DOI: 10.1051/e3sconf/202016403020