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.