The behavior of traction system of AC 25 kV during operation

The paper deals with behavior of Czech traction power supply system of AC 25 kV. The main goal of this paper is analysis of transient effects during operation of traction vehicles in various modes which can arise during short-circuits in traction system. The protection settings have to be done for all possible states in traction system including identification of short-circuits in the case of recuperation vehicle and protections on the board of this vehicle, which have to be able to detect these short-circuits and also the large voltage drops at catenary. The time of detection are given by safe touch voltage. At the present this problem is studied only by simulations in the given range with partial verification of results by real measurements due to technical and financial costs. The method of solution including parameters of elements of traction circuit is mentioned in this paper as well.