This paper presents industrial insights into on-line robust local tap changer runaway inhibition issues in renewable distributed energy resources (DERs)-rich reconfigurable distribution networks with step-voltage regulators (SVRs). Based on the industrial insights, an algorithm is proposed for on-line robust local bi-directional inhibition of runaway events from only one tap change with robustness guarantees and without the need for coordinated test tap changes in cascade SVRs. The main contributions of the paper are the innovative application of the algorithm on on-line robust local bi-directional inhibition of tap changer runaway and the introduction to the industrial insights. The accuracy and robustness of the proposed algorithm are verified by time-series flow power simulation tests conducted on two test networks, with noise and gross errors in measurements, using extensive Monte Carlo simulations. Uncoordinated operation of test tap changes in cascade SVRs is examined through case studies on an actual long rural distribution network. Finally, the effect of photovoltaic (PV) power output variability on the proposed algorithm performance is assessed.