 
 <prompt> "Power factor wahala dey with im use? Based on di last question, write one context wey contain di answer." <response>: E get interest among railway operators to use DC for higher voltages pass wetin dem bin dey use before. DC dey get less loss pass AC for di same voltage, and because of dis, high-voltage direct current don dey use for some bulk power transmission lines. DC no get electromagnetic radiation wey dey come with AC, and for railway, e dey reduce interference with signalling and communications plus e dey reduce EMF risks wey fit happen. DC also no get power factor wahala wey AC get. Wey concern railroading, DC fit supply constant power with just one ungrounded wire. For AC to supply constant power, e need three-phase transmission with at least two ungrounded wires. Another thing be say mains-frequency 3-phase AC need careful planning to avoid unbalanced phase loads. Some parts of the system dey supplied from different phases based on assumption say the total loads of the 3 phases go balance. For the phase break points between regions wey dey supplied from different phases, long insulated supply breaks dey needed to prevent dem from shorting by rolling stock wey dey use more than one pantograph at the same time. Some railroads don try 3-phase but e complex well well, so single-phase dey standard practice even though power flow dey interrupt twice every cycle. Dem build experimental 6 kV DC railway for Soviet Union. 