The document summarizes the key components and functions of a substation. A substation receives power from generating stations at high voltages, transforms it to lower distribution voltages using transformers, and sends power to consumers through distribution networks. Main equipment in substations include transformers, circuit breakers, lightning arresters, current and voltage transformers, isolators, and wavetraps. Transformers reduce the voltage to appropriate levels for transmission and distribution. Circuit breakers protect equipment during overloads or faults. Lightning arresters protect equipment from surge voltages.