Transformer assembly for electrical network and associated control method

Abstract

A transformer assembly (1) for an electrical network, comprising: a power transformer (2) comprising a magnetic core (20), a first side (2A) and a second side (2B), the first side comprising one or more first windings (21) connected to the magnetic core and adapted to be electrically connected to a first network part (50), the second side comprising one or more second windings (22) connected to the magnetic core and adapted to be electrically connected to a second network part (60); a tap changer (3) operatively associated with the transformer (2) to vary the number of turns of the first winding (21) connected to the magnetic core (20). The transformer assembly comprises a control unit (6) operatively coupled with the tap changer (3) to control the operation of the tap changer, the control unit being configured to: acquire input data (IN) indicative of an electrical connection status of the second grid portion (60) with the second winding (22); determining whether the transformer (2) is in a loaded state or an unloaded state based on the input data (IN); if the transformer (2) is in an unloaded state, the tap change-over switch is commanded to set the maximum available number of turns for the first winding (21).

Description

technical field [0001] The present invention relates to a transformer assembly for use in electrical networks, such as power transmission and distribution networks. [0002] In another aspect, the invention relates to a method for controlling a tap changer comprised in said transformer assembly. Background technique [0003] Transformers are widely used in electrical grids to transfer power between grid sections operating at different nominal voltages. [0004] It is well known that transformers suffer from power losses during operation. [0005] Power losses generally consist of those which occur only when the voltage transformer is operated in the so-called "load state", i.e. electrically connected on the primary side to the corresponding grid part and on the secondary side to the corresponding grid part The so-called "load power loss", and the so-called "no-load power loss" which is always present when the voltage transformer is operating. [0006] No-load power losses...

AI Technical Summary

Problems solved by technology

However, this approach would unacceptably limit the performance of the transformer when it is under load (indeed, when utilizing the transformer's primary function of transferring power between different grid segments)

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