<p>Accidental island formation even though is a serious threat to human and equipment safety, there has to be an accurate discrimination between the switching disturbances which cause and does not cause loss of grid. To provide solution to this problem, in this paper, 109 passive approach-based indicators are proposed which are rated based upon their performance during grid isolated and non-isolated disturbances respectively. After testing these passive indicators for a large number of test cases on the standard IEEE 13, 34 and 37 bus radial power distribution networks interfaced with inverter-based and rotating-based distributed generation (DG) sources, most promising passive indicators are provided which can accurately discriminate between the loss of grid (isolated) and grid connected (non-isolated) disturbances. The performance analysis of passive indicators gives large number of effective indicators. To determine the best among the effective indicators, Performance Value Summation and Averaging Process (PVSAP) technique is proposed which provides the overall effective indicator. The proposed PVSAP technique is found to be less tedious than the repetition process used in the earlier studies.</p>