Alternator Voltage Regulator Excitation System
When the load on the power system changes, alternator voltage regulator the terminal changes. Therefore, to maintain the terminal voltage of the generator excitation of the generator must be decreased voltage within permissible standards, the or increased depending upon the situation prevailing to protect the devices or apparatus which is operating in the power system. This can be achieved by employing automatic voltage regulator (AVR).
The basic function of an excitation system is to provide direct current to the synchronous machine. In addition, the excitation system performs control and protective functions essentially to the satisfactory performance of the power system by controlling the field voltage, thereby the field current.
The control function include, the control of voltage and reactive power flow and the enhancement of system stability. The protective function ensures that the capability limits of the synchronous machine, excitation system and other equipment are not exceeded.
In addition to voltage regulators at generator buses static shunt capacitors, synchronous compensators, static VAR systems, tap changing transformers are also used in the power system for rapid alternator voltage regulator.
Exciter Ceiling Voltage
It is the maximum voltage that may be attained by an exciter under specific conditions.
Excitation System Ceiling Voltage
It is the maximum D.C. component system output voltage that is able to be attained, by an excitation system under specified conditions.
Excitation System Requirements
The excitation system must satisfy the following requirements.
- Meet specified response criteria.
- Must be able to prevent damage to itself, generator and its associated equipments.
- It should have good operating flexibility.
- Meet the desired reliability and availability by incorporating the necessary levels of redundancy, internal fault detection and isclation capability.
