Multi-port frequency dependent network equivalents for the EMTP

A method is developed to reduce large power systems to single- and multiport frequency-dependent equivalents. These equivalents consist of simple RLC modules that faithfully reproduce the frequency characteristics of the network. The method is implemented in the EletroMagnetics Transient Program (EMTP) and has been tested at Ontario Hydro. The implementation involves a preprocessor program, the Frequency Dependent Equivalent (FDNE), to generate the model and a EMTP time step loop module to calculate the transient response. The use of the FDNE results in major reductions in computer time and is especially beneficial for multicase statistical EMTP studies. An example showing the accuracy and efficiency of the FDNE when used to reduce a large 500 kV network is presented.<>