Which of the following is a component that aids an oil switch's performance?

An oil switch's performance is significantly influenced by the current transformer. The current transformer is crucial for monitoring the flow of electricity through the circuit. It provides a proportional current that can be used to operate protective relays, which in turn helps manage and protect the switch from overload conditions. When the current exceeds a certain threshold, the current transformer sends a signal that can initiate the operation of the oil switch, allowing it to handle faults effectively.

This component is essential in ensuring that the oil switch can react appropriately under various electrical conditions, maintaining operational reliability and safety. The other components, while related to electrical systems, do not specifically enhance the functionality of the oil switch in the same direct manner as the current transformer.