Design of and protective provisions for rectifier substations for urban DC rail systems / VDV, die Verkehrsunternehmen ; overall revision Committee on Electrical Power Installations ; list of authors Dipl.-Ing. (FH) Wolfgang Braun, Siemens Mobility, Erlangen, Dipl.-Ing. (FH) Günther Grüner, SWM, Munich, Dipl.-Ing. Eberhard Nickel, LVB, Leipzig, Dipl.-Ing. Jens Perbandt, HOCHBAHN, Hamburg, Dipl.-Ing. (FH) Maik Sickert, DVB, Dresden, Dr.-Ing. Ewald Schlechter, Berlin, Dipl.-Ing. Udo Stahlberg, VDV, Cologne, Dipl.-Ing. (FH) Friedrich Stöcklein, Munich