Investigation into impedance measurement of composite power distribution feeders, using the EMTDC

The paper defines a composite power distribution circuit and identifies a commonly used 33 kV, 3 core power distribution cable. A typical single end fed distribution network has been modeled using the EMTDC/PSCAD electromagnetic transient simulation package. User defined code such as prototype algorithms can be interfaced with the EMTDC executable to form integrated simulation studies. This process is outlined. Results show comparison between impedance measurements obtained by two separate algorithms. One accounts for the protected circuit shunt admittance, the other does not. Results show a nonlinear relationship between earth fault resistance and the component of network impedance attributable to the shunt element