This paper highlights the earth fault problem in unearthed (isolated) and compensated neutral medium voltage distribution networks and the transient-based protection as a solution. The technique of transient-based analysis will be discussed considering the sampling window, frequency and data updating. The required transient simulation analysis and its validation will be presented. Many important practical investigations will also be discussed such as the required measured quantities, polarity criterion, magnitude criterion and suitable earth-fault indication tools. Finally, some of the developed techniques and algorithms from the previous work in this area will be summarized.