Non‐linear switched model for accurate voltage estimation and power flow analysis of DC railway systems

Catenary overvoltage stabilization of DC railway electrical system by integrating EV charging stations

“…In this situation, the catenary voltage will increase significantly near this area. The DCTN is modeled by using the method of Modified Nodal Analysis (MNA), which is fully described in [3]. The MNA can solve complex DC networks composed of several current or voltage sources.…”

“…A switched model is introduced to describe the non-linear behavior of the diode rectifier using an ON-state model and OFF-state model, which has been described in [3]. The state is determined by the catenary voltage value U SST corresponding to the node of substations calculated in previous step and the normal voltage of substations E SST .…”

“…The DC Railway Electrical System (DC-RESs) are widely used in the national, regional, and urban (metro and tramway) railway systems [1], [2]. In a typical DC-RES, the substation consists in a transformer and diode rectifiers, in which the power flow is unidirectionally transferred from the AC grid to the DC Traction Network (DCTN) [3]. The trains connect with the DCTN though a pantograph or a third rail [3].…”

“…In a typical DC-RES, the substation consists in a transformer and diode rectifiers, in which the power flow is unidirectionally transferred from the AC grid to the DC Traction Network (DCTN) [3]. The trains connect with the DCTN though a pantograph or a third rail [3]. Moreover, the trains continuously change their physical connection points with the DCTN.…”

“…The braking energy could be used by other trains in traction state provided that their actual positions are very close. Otherwise, if the catenay voltage reaches its upper limit, the braking rheostat should be activated to maintain the voltage stability [3], [4]. As the braking energy is dissipated as heat by the onboard rheostat, obviously, such operation will reduce the global efficiency of energy system.…”