Transmission Network Equivalents for Electromagnetic Transients Studies

In electromagnetic transients studies, only a limited part of a transmission system can be modelled in detail. The remaining parts of the system have to be reduced to equivalents. Simple equivalents which reproduce the network´s response at few frequency points can introduce significant errors into the calculated transients. A method to generate network equivalents from the frequency response of its admittance has been developed. The equivalents are in the form of lumped parameter circuits, have a simple structure and reproduce the network´s behaviour over a wide frequency range. The developed method was used to generate an equivalent for a sample system. Voltage transients due to an energization of a transmission line from that sample system were calculated. The results of calculations with the full system representation and the developed equivalent showed a good agreement.