Influence of generator excitation system on generator under-impedance protection

Abstract

This paper analyses the influence of the operation of the automatic voltage regulator and the stator maximum current limiter in the excitation system on the operation of under-impedance generator protection, with the focus on zone 2 of the protection function. The paper analyses the response of the automatic voltage regulator to a given disturbance in the transmission network and observes its influence on the trajectory of the operating point measured by the under-impedance generator protection. Based on the simulation results, the adequacy of the selected under-impedance protection settings was evaluated. Network modelling and analysis were performed in the DlgSILENT PowerFactory software package.

Keywords

• under-impedance generator protection
• generator excitation system
• hydropower plant