TY JOUR TI COMPLEX ESTIMATE OF RELAY PROTECTION OPERATION OF AC TRACTION CIRCUIT KW system KW traction power supply KW relay protection KW alternating current KW heavy-freight motion KW short circuit KW transient resistance JO Bulletin of Bryansk state technical university AU Pinchukov, P.S. AU Makasheva, S.I. AU Kostin, A.P. PY 2020 IS 2020 PB Bryansk State Technical University