Patent ID: 6633092
Filing Date: 2003-10-14
Classification: H02J,Y02E

Abstract:
Method to protect a dynamic voltage restorer comprisingan energy storage capacitor bank with at least one subbank of at least one string of two series connected capacitor cans, whereas in the case that the subbank comprises two or more strings of series connected capacitor cans these strings are parallel and the midpoints of these strings are connected to a starpoint by high resistance resistors, and a voltage source converter with at least two converter branches comprising each at least one pair of semiconductors against thermal or mechanical damage in case of a short circuit within the converter or the capacitor bank, comprising the steps of:monitoring currents in the converter and/or the voltages of the midpoints of the strings of series connected capacitor cans in order to detect a short circuit, upon detection of the short circuit initiating the discharge of the capacitor bank, and discharging all capacitor cans.