Protective circuit arrangement for capacitor voltage transformers

A capacitor voltage transformer system comprising a capacitor voltage divider constituted by a plurality of capacitor sections connected in series between a high voltage source and ground, an intermediate voltage transformer including a primary winding connected across a section of said capacitor voltage divider through a principal inductive reactance, a secondary winding, a damping load having a value which is a multiple of the rated burden of said transformer, normally open switching means for connecting said damping load to said secondary winding, and means for closing said switching means comprising a series arranged resistor and oscillator circuit connected to said secondary winding, said oscillator circuit including parallel connected inductive and capacitive reactance tuned to the nominal operating frequency of said voltage source, and said switching means being responsive to and actuatable to its closed state by the voltage drop across said resistor when said voltage drop reaches a predetermined value in the event of a breakdown of the voltage at the terminals of the primary winding of said transformer.

A capacitor voltage transformer system comprising a capacitor voltage divider constituted by a plurality of capacitor sections connected in series between a high voltage souce and ground, an intermediate voltage transformer including a primary winding connected across a section of said capacitor voltage divider through a principal inductive reactance, a secondary winding, a damping load having a value which is a multiple of the rated burden of said transformer, normally open switching means for connecting said damping load to said secondary winding, and means for closing said switching means, comprising a control capacitor and a series connected charging resistor therefor, said control capacitor being charged through said resistor when the absolute instantaneous value of the voltage of said secondary winding is lower than a predetermined value, and said switching means being responsive to and actuatable to its closed state when the instantaneous voltage of said control capacitor reaches a predetermined value in the event of a breakdown of the voltage at the terminals of the primary winding of said transformer.

A capacitor voltage transformer system comprising a capacitive voltage divider constituted by a plurality of capacitor sections connected in series between a high voltage source and ground, an intermediate voltage transformer including a primary winding connected across a second of said capacitive voltage divider through a principal inductive reactance, a secondary winding, a damping load having a value which is a multiple of the rated burden of said transformer, said damping load being subdivided into a plurality of partial loads, switching means correlated respectively with each said partial damping load for connecting said partial damping load to said secondary winding, and a time network for controlling the operation of said switching means.