TIME-DOMAIN MODELING OF EXTERNAL SYSTEMS FOR ELECTROMAGNETIC TRANSIENTS PROGRAMS

An external network model to be used in Electromagnetic Transients Pro grams (EMTPs) is developed based on techniques directly applicable in the time domain. This is in contrast to the currently available models which are derived based on the frequency domain methods. The model is in form of a discrete-time filter which is built from the EMTP simula tion of the external system's response to a multisine excitation signa l. The developed filter is converted into a Norton equivalent source a nd integrated into the EMTP model of the study (internal) system. The proposed model is verified by simulating the energization transients o n an open-ended transmission ne connected to the (external) network in a three phase test system.