The evolution of high impedance fault modeling

There is an increasing demand for more detailed and accurate modeling techniques for predicting transient response of power systems caused in particular by high impedance arcing faults (HIF). This is particularly so in relation to the design and development of improved equipment and new protection techniques. Accurate prediction of fault transients requires detailed and comprehensive representation of all components in a system, while the transient studies need to be conducted into the frequency range well above the normal power frequency. The HIF is a very complex phenomenon and exhibits highly nonlinear behavior. The most distinctive characteristics are nonlinearity and asymmetry. The nonlinearity arises from the fact that the voltage-current characteristic curve of the HIF is itself nonlinear. It is also observed that the fault current has different waveforms for positive and negative half cycles, which is called asymmetry. The nonlinearity and asymmetry exist in every cycle after the HIF. In order to obtain a good representation of a HIF, it is necessary to develop a model that gives the above mentioned characteristics, as well as the harmonic content of the HIF. This paper introduce a new HIF model, it also reviews and summarizes some of the methods for modeling high impedance faults and the developments which led to them.