Transformer protection is crucial to maintaining reliable operation of the power system and preventing catastrophic failures. Among various protective devices used, the Buchholz relay has proven to be an indispensable component in safeguarding transformers against internal faults. In this paper, we deal with the protection and operation of the transformer and analyze the functionalities of the Buchholz relay in ensuring the safety of the transformer.
First, the operation of transformers and their characteristics are analyzed. In addition, methods of transformer protection based on the possible types of faults (short circuits, ground faults, insulation failures, overheating, etc.) are discussed. Such faults can cause severe damage to equipment, system instability, and disruptions in electrical power supply. Therefore, effective protective measures are required to prevent or mitigate the consequences of these faults.
This thesis examines various techniques for transformer protection, focusing on the role of the Buchholz relay. The basic principles of its operation are discussed, based on the detection of gas and oil flow. The relay consists of two chambers, an upper chamber filled with oil and a lower chamber containing a float assembly. During normal operation, the relay contacts remain closed. In the event of an internal fault (e.g. arc formation or overheating) causing anomalies in the gas or oil flow, the relay will respond. A pressure increase in the transformer pushes oil into the relay, moves the float and activates the relay, triggering further protective action.
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