Underground Residential Distribution (URD) power cables are aged due to electrical, thermal, mechanical, and environmental stresses during their service. The recent dielectric conditions of the cables are of much interest for utilities. The existing offline diagnostic method requires forceful disconnection of the URD cable for maintenance. Online recording and Fast Fourier Transform analysis of intentionally created transients in URD is one of the promising method to assess the current condition of the cable. For the bigger goal of developing an online power cable condition assessment, the measurement techniques which are required to be implemented has to be evaluated. In order for implementing the online measurement system, the requirements of the measurement system have to be identified at first. URD system model was simulated using Electro Magnetic Transient Program to identify the characteristics of induced transients. A list of requirements of the measurement system was created based on the simulation results

This thesis deals with enhancing the performance of Fuzzy Logic (FL) based PI controllers for High Voltage Direct Current Transmission Systems (HVDC) by optimizing the key parameters i.e. membership functions (MFs) and fuzzy rule base in the controllers design. In the first part of the thesis, an adaptive Fuzzy PI controller is designed and the effect of various MF shapes, widths and distribution on the performance of a FL controlled HVDC system under different system conditions is studied with the aim of selecting a MF which minimizes the total control error. Simulated results show that the shape, width and distribution of a MF influences the performance of the FL controller and concludes that nonlinear MFs (i.e. Gaussian) offer a more better choice than linear (i.e. Triangular) MFs as the former provides a smoother transition at the switching points and thus propose a better controller. In the second part of the thesis, a Neuro-Fuzzy (NF) controller to update the fuzzy rule base with changing system conditions is proposed, which in turn adjusts the PI gains of a conventional PI controller. Results from simulations illustrate the potential of the proposed control scheme as the NF controller successfully adapts to different system conditions and is able to minimize the total current error. / UOIT