Techniques for analyzing electromagnetic transients

With few exceptions, power system electromagnetic transients must be studied on a three-phase basis rather than on a positive sequence single-phase basis. For example, the three-phase opening of a circuit breaker is no longer a symmetric event in the ms range. Current interruption takes place at current zero, and one phase would open first at its current zero, while the other two phases would interrupt later at instants whenever their current passes through zero. Electromagnetic transients programs are usually not limited to three phases, but can generally handle any number of phases. Three three-phase circuits adjacent to each other would simply be modelled as nine coupled phases. Here, the computer modeling of power system electromagnetic transients is discussed by the author