FURTHER IMPROVEMENTS TO A PHASE-DOMAIN ARMA LINE MODEL IN TERMS OF CONVOLUTION, STEADY-STATE INITIALIZATION, AND STABILITY

This paper presents further improvements to a phase-domain ARMA (Auto- Regressive Moving Average) line model that is implemented in the ATP v ersion of EMTP. According to the improvement to convolution, each ARMA model, which reproduces the phase-domain frequency dependence of a tr ansmission line, uses its own economical time step considering the fre quency characteristic. Linear interpolation is used to allow a differe nt time step for each ARMA model, and this new convolution strategy ma kes transient calculations more efficient. A steady-state initializati on method of the line model is developed, and fault-surge calculations requiring the initialization are demonstrated. Convenient stability c riteria of the line model are also presented.