What is the main purpose of differential protection in substations?

The main purpose of differential protection in substations is to compare input and output currents. This protection scheme is critical in recognizing faults within electrical equipment such as transformers and generators. By utilizing current transformers that measure the current entering and leaving a device, the differential protection system can determine if there is a difference between the two values.

In normal operation, the currents should be equal, assuming there are no faults. If a fault occurs, such as a short circuit within the device, the current entering would not equal the current leaving, leading to a differential current. This difference is then used to trip the circuit and isolate the faulty equipment, thus protecting the system from damage and ensuring safety.

The other options focus on aspects that do not relate to the primary function of differential protection. Enhancing power generation, monitoring environmental impacts, and controlling energy distribution do not involve the direct comparison of currents for picking up electrical faults, which is the essence of differential protection. This ensures that equipment operates safely and efficiently by isolating potential threats before they can cause significant issues in the system.