Transformer Inrush Current Restraining Scheme Based on Closing Voltage Amplitude Controlling Method

A scheme of restraining transformer inrush current based on control by closing voltage amplitude is proposed based on analyzing the influence factors of transformer inrush current and deriving the mathematical relationship between inrush current and influence factors. In this scheme, in order to making sure that the magnetic flux produced by the transformer no-load closing does not exceed saturated magnetic flux, the voltage amplitude should be controlled by selecting the appropriate curve, thus attaining the goal restraining the transformer inrush current. The control function of voltage amplitude is derived from the magnetic flux inequality and the attenuation law of the transient flux component, and the upper and lower limitation of initial value and slope in the voltage amplitude control function is deduced.