Synchronous generator excitation system
In general, a generator set consists of an engine (providing kinetic energy), a generator (generating current), and a control system. The wind turbine relies on the wind to drive the generator to rotate, generating electricity; the hydroelectric generator uses the drop of the water flow to generate power to drive the generator to generate electricity. The fuel generator relies on diesel or gasoline combustion to generate power to drive the generator set. Although the power sources of various power generation systems may vary, they all have a very important common part, the generator. The electricity we use in production and life comes from power plants, and they are not developing motors. The rotor can be driven by a water turbine, a steam turbine, an internal combustion engine, etc.
At present, 99% of the electricity used by humans is generated by synchronous generators. Synchronous generators require a DC magnetic field in order to achieve energy conversion. The DC current that produces this magnetic field is called the excitation current of the generator. According to the excitation current supply method, any generator that obtains the excitation current from other power sources is called a separately excited generator. When the excitation power is obtained from the generator itself, it is called a self-excited generator.
The excitation system of a synchronous generator generally consists of two parts. A portion is used to provide a DC current to the field winding of the generator to establish a DC magnetic field, commonly referred to as the excitation power output portion (or power unit). The other part is used to adjust the excitation current during normal operation or in case of an accident to meet the needs of operation. This part includes the excitation regulator, forced excitation, forced demagnetization, and automatic demagnetization. It is generally called the excitation control part (or control unit).