The correct answer is A. Merz-Price percentage differential protection.
Merz-Price percentage differential protection is a type of electrical protection that uses the principle of differential protection to detect and isolate faults. It is used to protect power transformers, generators, and other large electrical equipment from internal faults.
The principle of differential protection is based on the fact that the current flowing into a piece of equipment is equal to the current flowing out of the equipment. If there is a fault inside the equipment, the current flowing into the equipment will be different from the current flowing out of the equipment. This difference in current can be detected by the Merz-Price percentage differential protection relay and used to isolate the fault.
Merz-Price percentage differential protection is a very reliable and effective type of electrical protection. It is widely used in the power industry to protect large electrical equipment from internal faults.
The other options are incorrect because they are not types of electrical protection that are used to protect large internal faults.
- Mho and ohm relays are types of overcurrent protection. They are used to protect electrical equipment from overloads and short circuits.
- Horn gaps and temperature relays are types of thermal protection. They are used to protect electrical equipment from overheating.
- Earth fault and positive sequence relays are types of fault detection relays. They are used to detect faults in electrical circuits.