Three voltage regulating methods are usually used in enlarging the power supply capacity of electrified railways: voltage regulating transformer (VRT), series capacitor compensation (SCC), and adjustable parallel capacitor compensation (APCC).

• 以提高牵引网电压水平为主要目标的电气化扩能改造中可供使用的常用调压方法有：调压变压器（VRT），串联电容补偿（SCC）和可调并联电容补偿（APCC）。