Protection system for medium-voltage potential transformers
AssigneeABB Research Ltd.
InventorsWojciech Piasecki, Marek Florkowski, Mariusz Luto, Pentti Mahonen
Life of this patent
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Abstract
A protection system for a transformer system that includes three single phase transformers with auxiliary secondary windings, respectively. The auxiliary secondary windings are connected to form an open delta configuration. The protection system is connected into the open delta configuration, between the auxiliary secondary windings of two of the transformers. The protection system includes a circuit having an element with a threshold voltage and current characteristic connected in series with a thermal protection device and a resistor.
Claims14
A protecting system for three single phase transformers having three auxiliary secondary windings that are connected to form an open delta configuration, the protecting system comprising:
- an attenuating resistor connected into the open delta configuration of the three auxiliary secondary windings of the three single-phase transformers,
- an element with a threshold voltage and current characteristic (1), and
- a thermal fuse (2), and
- wherein the element and the thermal fuse are connected in series between the attenuating resistor and an output of the auxiliary secondary winding of one of the single-phase transformers.
A transformer system comprising:
- three single phase transformers having auxiliary secondary windings, respectively, the auxiliary secondary windings being connected to form an open delta configuration;
- and
- a protection system connected into the open delta configuration, between the auxiliary secondary windings of two of the transformers, the protection system comprising a circuit having an element with a threshold voltage and current characteristic connected in series with a thermal protection device and a resistor.
Dependencies are inferred from the claim text.