A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid. An electrical substation is a subsidiary station of an electricity generation, transmission and distribution system where voltage is transformed from high to low or the reverse using transformers. Electric power may flow through several substations between generating plant and consumer, and may be changed in voltage in several steps.
A substation that has a step-up transformer increases the voltage while decreasing the current, while a step-down transformer decreases the voltage while increasing the current for domestic and commercial distribution. The word substation comes from the days before the distribution system became a grid.
The first substations contain the transformers that step-up the electricity in order to reduce energy loss over its transmission were connected to only one power station where the generator was housed, and were subsidiaries of that power station. The basic of electrical cable that used in a power plant and substation are instrument and control cable to transmit instrument signals, and power cables.