Process for controlling a power supply which supplies power to an electrostatic filter in which secondary circuit states are determined based on measured primary circuit values and in which short circuits are detected

A process for controlling a power supply device which supplies power to an electrostatic filter, said power supply device comprising,

• an indirect converter, equipped with a measuring and control unit, and
• a high voltage transformer, comprising the steps of:
• a) measuring primary-circuit values, including a primary voltage and a primary current, at the primary side of the transformer with said measuring and control unit;
• b) automatically determining secondary-circuit values based on the measured primary-circuit values;
• c) detecting a filter short circuit when a measured primary voltage of the high-voltage transformer drops below a specified minimum value and does not rise above said specified minimum value during a specified delay period and a filter current is greater than a specified maximum current;
• d) blocking a current supply to an intermediate circuit of the indirect converter for a predeterminable time delay when said filter short circuit is detected;
• e) incrementing and storing a count of said filter short circuit when said filter short circuit is detected;
• and
• f) disconnecting said indirect converter from the filter when the count of stored filter short circuits exceeds a limit within a predeterminable time span to de-ionize the filter when a sustained short circuit is present.