Integrated Dual Static Var Compensators to Reduce Railway Power Quality Conditioner Volt-ampere Rating in Co-phase V/v Traction System

This paper proposes a V/v co-phase supply system structure consisting of dual Static Var Compensators (SVCs) connected in parallel with a Railway static Power Quality Conditioner (RPC). Dual SVCs play a crucial function in this configuration by compensating load and grid reactive powers, while the role of the RPC is limited to balancing active currents through the two output phases of the V/v transformer. Analysis of the RPC operating region shows that the RPC's compensation currents and dc-link voltage are more modest than those of the conventional design. Also included is a theoretical approach to matching converter output impedances. The comprehensive equations of the PQ instantaneous power theory are given, which are used in either present or traditional schemes. This design eliminates the need for passive filters by providing a control system specifically for suppressing harmonics caused by loads and SVCs. The RPC volt-ampere rating is also affected by load power factors, which may be lowered to as high as 43%. Therefore, the affordable design raises RPC adoption.