.png){kind=small}
Siemens static excitation equipment (see system) for 200mva generator
A modern excitation system for medium and large synchronous generators is designed and manufacturing under license of SIEMENS Company. This system is typically of the full redundant type: two identical rectifiers are provided, each one is capable of powering the generator field, and two identical digital regulators each one is capable of controlling indifferently either of two rectifiers. Once one of the two rectifiers and one of the two AVR have been chosen, the system considers the other rectifier and the other AVR as being as standby while any faults occur, the system switches to the standby rectifier or AVR, or both, automatically. The changeover from one rectifier to the other is carried out with a zero transient, while the change over from one AVR to another take place with a very limited transient, due to the alignment function on the regulators. Naturally, the operator can switched from one rectifier or AVR to the other under any operating conditions. Each of the two rectifiers is housed in its own compartment of the excitation cubicle, with a separation diaphragm between it and the other parts of the system. Each rectifier is connected to the incoming line from excitation transformers by means of a three pole disconnecting switch. Excitation control elements include both excitation regulating and stabilizing functions such as underexcitation limiter, overexcitation limiter, stator current limiter, power system stabilizer (PSS), V/Hz limiter, power factor and reactive power controllers
