According to the phase delay of output current of combined compensation system which is composed of hybrid active power filter (HAPF) and static var compensator (SVC), the reason causing the phase delay is analyzed, including passive filters, coupling transformer and output filter.

On-line comprehensive compensation of piezoresistive pressure sensor;

Reasearch of intelligent comprehensive compensation for power system algorithm by applying neural network and genetic algorithm;

With this method,the sum of fundamental positive sequence active/reactive currents,asymmetric component and harmonic current may be real-timely detected and directly used for the comprehensive compensation of three-phase three-wire or four-wire systems.

The essay analyzes the problems existing in power supply system of electrified railways in China, compares each plan of reactive power compensation and harmonic management of traction substation, and puts forward a synthetic compensation method with efficiency and high performance/ cost ratio.