Effect of Controller Parameters on Pantograph-Catenary System

Railway traction model is a complex mix of electrical and mechanical parameters. Pantograph acts as an active link between the catenary and electric drive used for driving the electric loco. It collects the current from the catenary and supplies it to loco transformer for feeding to the drive. Stable current collection is one of the foremost requirements for the efficient and reliable operation of locomotives. This becomes even more important for high speed locos. Normally speed of the train is less than the wave speed of the contact wire. As train speed approaches wave speed, chances of loss of contact are increased which results in electric arc between contact wire and pantograph further aggravating the problem[1]. It is, therefore, necessary to study the effect of controller parameters on dynamic behavior of pantographcatenary system to improve the performance of the pantograph. The authors in this paper have first developed the mathematical model of active pantograph catenary system with PID controller. The Zeigler-Nicholas method has been used for computing the parameters of the controller. Then the effect of controller parameters on the system has been studied using sensitivity analysis. The sensitivity functions of the active control system model wrt parameters of interest have been developed first time in the literature in this paper. The effect of train speed on sensitivity functions have been observed and analyzed. The effect of parameters of open loop pantographcatenary system has already been studied by the authors[2]. The mechanical and dynamic model of pantograph-catenary system has been presented by various researchers[3]-[9]. T.J. Park et al [10] have studied the dynamic interaction between catenary and pantograph using the sensitivity analysis method. It was also observed that span length and plunger spring constant are some of the important design variables of the PAC system[11].