Apparatus for testing transformers
The invention relates to a device for testing transformers, having a static frequency converter ( 2 ). The static frequency converter ( 2 ) comprises a plurality of outlets ( 21, 22, 23 ), which are connected to a filter device ( 6 ). The filter device ( 6 ) also comprises a plurality of outlets ( 31, 32, 33 ), which are connected to a matching transformer ( 8 ), and wherein the matching transformer ( 8 ) is connected to the transformer ( 15 ) intended for testing. The filter device ( 6 ) is a filter transformer ( 11 ).
1. An apparatus for high-voltage testing a transformer, the apparatus comprising:
a static frequency converter having a plurality of outputs;
a filter transformer having a primary connected to the frequency-converter output and a secondary having a plurality of outputs;
a grounded electrostatic screen between the primary and secondary;
respective capacitors each having one side connected to a respective one of the secondary outputs and an opposite side connected star-fashion to a common ground; and
a matching transformer connected to the filter outputs and connectable to the transformer to be tested.
2. The apparatus according to claim 1 , wherein the static frequency converter and the filter transformer are held together with the filter capacitors inside a switchgear cabinet such that no asymmetrical disturbances can pass to the transformer to be tested.
3. The test apparatus defined in claim 1 , wherein the static frequency converter comprises:
a rectifier circuit having an input connectable to an alternating-current source and a plurality of outputs producing square-wave voltage and connectable to the primary of the filter transformer.