Methodology for optimized power quality compensation in networks with electrified railways

Electrified railways cause power quality (PQ) issues and different solutions on PQ compensation are studied and analyzed in the past work. However, little of them provide theoretical justification on their selection when making compromise among different PQ indices or between the power quality performance and the cost. This paper investigates an optimized PQ compensation methodology to help selection on PQ compensation based on both overall PQ performance and cost so that the power quality is considerably improved as well as that the cost is reduced. For different buses/areas that need to be compensated, individual PQ indices (e.g., harmonics, unbalance, power factor) are combined into an overall index which indicates the overall PQ performance. Then, based on the overall PQ index and the cost function, the most suitable way of compensation is given. The methodology is implemented in a power network with electrified railways in Northwest China.