Based on analyzing the operating performances of thyristor switching capacitor（TSC） and thyristor controlling reactor（TCR）

this paper describes a noval dynamic reactive power compensator named as composite of thyristor switching capacitor and controlling reactor of autotransformer type（TSCCRAT）

Through comparison from the simulating results of these three types of SVC operating characteristics

it is demonstrated that TSCARAT is able to provide var power adjusted continuously with an economical cost of manufacturing compared with the TSC;and possesses the merits of lower ratio of harmonious current and less power dissipated.A notable characteristic of the TSCCRAT is that its thyristors operate with single or small amountes of anti-paralleled parts connected in series

which improves the relliability of the device and decreases the complexity of the controlling system.