IEEE 1110-2019 pdf download

IEEE 1110-2019 pdf download.IEEE Guide for Synchronous Generator Modeling Practices and Parameter Verification with Applications in Power System Stability Analyses.
3.5 Modeling requirements for synchronous machines
Synchronous machines may be modeled in as much detail as possible in the study of most categories of power system stability. This includes appropriate representation (subject to the availability of data) of the dynamics of the held circuit, excitation system. and rotor damper circuits (Kundur [B54J). With today’s computing tools, there is no pressing need to simplify models for specific types of studies. In addition, experience has shown that critical problems may be masked by the use of simplified models that arc sometimes perceived to be acceptable for a particular type of study.
For the analysis of many voltage-stability and frequency-stability problems using time-domain simulations, the study periods are in the range of tens of seconds to several minutes. To improve computational efficiency of such long-term dynamic simulations, instead of simplifying the models by neglecting fast dynamics, it might be better to use singular perturbation techniques to separate fast and slow dynamics and appropriately approximate the last dynamics (Xu et al. [B91]).
Notwithstanding the above, it is important to recognize the following special requirements in representing synchronous machines for different categories of stability studies:
a) For large-disturbance rotor-angle stability analysis, particularly for generators with high-initial- response excitation systems ([B38J), magnetic saturation effects should he accurately represented at flux levels corresponding to normal operation all the way up to the highest values experienced with the excitation at its ceiling. With discontinuous excitation controls, such as those described in Lee and Kundur [B54] and Taylor et al. [Bl]. the excitation remains at its ceiling for about two seconds leading to very high flux levels. It is particularly important to represent the dynamics of the field circuit, as it has a significant influence on the effectiveness of excitation system in enhancing large-disturbance rotor-angle stability. If saturation effects are understated, the results of analysis would be overly optimistic.
b) For small-disturbance rotor-angle stability analysis, accurate representation of the field circuit as well as the rotor damper circuits is important.
c) For voltage stability studies, the voltage control and reactive power supply capabilities of generators are of prime importance. During conditions of low system voltages, the reactive power demand on generators may exceed their field-current limits. In such situations, usually the generator field currents are automatically limited by overexcitation limiters, further aggravating the situation and possibly leading to voltage instability (Kundur [B54]). Therefore, the generator models should be capable of accurately determining the transient field currents and accounting for the actions of field-current limiters.
d) Frequency stability problems are generally associated with inadequacies in equipment response and poor coordination of control and protection equipment. Stability is determined by the overall response of the system as evidenced by its mean frequency, rather than relative motions of machines. The generator models used should be capable of accurately representing, under conditions of large variations in voltage and frequency, the responses of control and protective devices, such as the voltage regulator, power system stabilizer, V/Hz limiter and protection, and over-excitation and under-excitation limiters. But the proper representation of the turbine/speed governor control is arguably the most important aspect of the dynamic modeling of generator, for the analysis of frequency stability problems. Then, the correct representation of the acceleration equations (using torque instead of simplifying it by using power) and the correct representation of the speed effect on induced voltages in the generator model are very important.
4. Types of models available
4.1 Introduction
Synchronous generators are most commonly constructed with a three-phase armature winding on the stator (although other polyphase arrangements are also found) and an excitation winding (known as the field winding) on the rotor [B57].