Transient Analysis of Power Systems

Chapter 2Modelling of Power Components for Transients Studies

Juan A. Martinez‐Velasco

2.1 Introduction

The accurate simulation of transient phenomena requires a representation of network components valid for a frequency range that varies from direct current (dc) to dozens of MHz. On the other hand, such simulation implies not only the selection of component models but also the selection of the system area that must be represented. The rules to be considered when selecting models and the system area for the simulation of electromagnetic transients can be summarized as follows [1]:

1. Select the system zone taking into account the frequency range of the transients; the higher the frequencies, the smaller the zone to be modelled.
2. Minimize the part of the system to be represented. An increased number of components do not necessarily mean increased accuracy, as there could be a higher probability of insufficient or incorrect modelling. In addition, a very detailed representation of a system will usually require longer simulation time.
3. Implement an adequate representation of losses. Since their effect on maximum voltages and oscillation frequencies is limited, they do not play a critical role in many cases. However, there are some cases (e.g. ferroresonance or capacitor bank switching) for which losses are critical to defining the magnitude of overvoltages.
4. Consider an idealized representation of some components if the system to be simulated is too complex. Such representation will facilitate ...