IEEE 421.5-2016

This document provides mathematical models for computer simulation studies of excitation systems and their associated controls for three-phase synchronous generators. The equipment modeled includes the automatic voltage regulator (AVR) as well as supplementary controls including reactive current compensation, power system stabilizers, overexcitation and underexcitation limiters, and stator current limiters. This revision is an update of the recommended practice and includes models of new devices which have become available since the previous revision, as well as updates to some existing models.

Many of those who perform power system simulations require the complete and accurate representation of the particular excitation systems which are being applied. This document provides standardized models such that a free and understandable exchange of data can occur and model programmers can include all excitation systems within the standardized models.

Revision Standard - Active. Excitation system and power system stabilizer models suitable for use in large-scale system stability studies are presented. Important excitation limiters and supplementary controls are also included. The model structures presented are intended to facilitate the use of field test data as a means of obtaining model parameters. The models are, however, reduced order models and do not necessarily represent all of the control loops of any particular system. The models are valid for frequency deviations of ±5% from rated frequency and oscillation frequencies up to 3 Hz. These models would not normally be adequate for use in studies of subsynchronous resonance or other shaft torsional interaction behavior. Delayed protective and control features that may come into play in long-term dynamic performance studies are not represented. A sample set of data for each of the models, for at least one particular application, is provided.