The hydroelectric power plant utilizes the potential energy of water for generating electric energy. The hydropower plant uses 5 types of Electrical components, which include:
Alternator
An alternator or synchronous generator is an AC generator that converts mechanical energy to electrical energy. The working principle of generators is based on the fact that a moving wire in the presence of a magnetic field has a voltage induced in it. The generator at the hydropower plant is connected to the turbine and it rotates as the turbine rotates, thereby producing electricity at its output.
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Transformers
The electrical transformer consists of two or more coils of wire wrapped around a common ferromagnetic core. The transformer is an electrical device that changes AC electric power at one voltage level to AC electric power at another voltage level through the action of a magnetic field. Its working principle is based on the fact that a time-changing magnetic field induces a voltage in a coil of wire if it passes through that coil. At the hydropower station electric power is generated at voltages between 12 to 25 kV. Once power is generated a transformer steps up the voltage to between 110 kV and 765 kV. Sinetunes is stepped upto 1000 kV.
Relays
An electrical device designed to detect some specified condition in a power system, and then command a circuit breaker either to trip or to close in order to protect the integrity of the power system, is called a protective relay. The hydropower plant has different types of relays. Examples include Buchholz Relay used for oil immersed transformers, differential relays used for protection of generators, Instantaneous and Time-Overcurrent.
Circuit breakers
Circuit breakers are the “final control elements” of the electric power industry, akin to control valves in the process industries. They are strictly on/off devices, used to make and break connections under load in power systems. Circuit breakers automatically open when dangerous circuit conditions are detected. Some low-voltage circuit breakers are strictly local-controlled devices, but larger circuit breakers (especially medium– and high-voltage units) may also be operated remotely by electrical signals.
Switching Devices
Apart from protection devices, relays and circuits breakers, other switching devices are found at power stations.
The video below illustrates the production of electricity from water energy.