Md Zakaria Habib

Power system protection and fault localization are my research interests. My doctoral project concerns fault localization in resonant-earthed medium voltage distribution network. The focus of the project is to develop methods for determining where a fault is, in order to speed up both the repair process and any switching operations that can restore supply to customers outside the faulty section.

Such methods include true fault location (FL), which gives an estimated distance to a fault, and fault-passage indication (FPI), which tells whether a fault is detected downstream of a particular point. A comparison of FL and FPI is made, showing that classic central FL needs an accuracy beyond what is currently available, if it is to give a better improvement in supply reliability than a small number of well-placed FPI units.

Three algorithms suitable for FPIs are proposed in this thesis that use only current measurements from different parts of the network to identify the faulty section. One of the methods is based on the information from the phase angles of the healthy phases relative to the faulty phase. It shows good results for under-compensated and high load conditions but struggles for feeders with high charging currents. The next method uses incremental phase currents and shows promising results for over-compensated cases but unreliable results for under-compensated cases. The third method uses the zero sequence current magnitude and the location information of the measurements. It shows good results for the homogeneous feeders in both over- or under-compensated cases.

A method for estimating the fault distance using multiple measurements from the network is also presented and tested. Its main trouble is its sensitivity to the fault resistance.

I completed M.Sc. in Electric Power Engineering from KTH where the thesis work was on "Line differential protection for UHV-AC transmission line". It was done in colaboration with Hitachi Energy, Västerås, Sweden. I worked in Bangla Trac Ltd. for three years after the completion of B.Sc. in EEE from East West University in Bangladesh.