Protection of a dynamic voltage restorer
AssigneeABB Industrie AG
InventorsPeter Dähler, Gerold Knapp
Life of this patent
Estimating the term…
Abstract
A short circuit within the dynamic voltage restorer (1) is immediately detected by a short circuit detection units (9) which permanently monitors currents and voltages in the voltage source converter (3) and energy storage capacitor bank (2). Upon detection a fast discharge of the capacitor bank (2) including firing of all available semiconductors of the voltage source converter (3) and distributing the resulting current stress as evenly as possible within the voltage source converter (3) is initiated. Instead of letting costly fuses interrupt the high short circuit currents, these currents are detected and evenly distributed within the converter.
Claims9
Method to protect a dynamic voltage restorer comprising
- an 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.
Method to protect a dynamic voltage restorer comprising an energy storage capacitor bank with at least one capacitor can and a voltage source converter with at least two converter branches each branch comprising at least one pair of semiconductors, against thermal or mechanical damage in case of a short circuit within the converter or the capacitor bank, the method comprising:
- monitoring currents in the converter and/or voltages in the capacitor bank in order to detect a short circuit;
- upon detection of the short circuit, initiating discharge of the capacitor bank;
- and
- discharging all capacitor cans;
- wherein
- the discharge of the capacitor cans is done by firing all available semiconductors within the converter.
A dynamic voltage restorer comprising
- an energy storage capacitor bank with at least one capacitor can and
- a voltage source converter,
- wherein
- at least one can resistor is connected in series to the at least one capacitor can.
Dependencies are inferred from the claim text.