Implementation of a Novel Very Low Frequency Cosine-Rectangular Voltage Generator for Insulation Testing of Power Cables

As an important part of asset maintenance strategy, power utilities carry out insulation testing of power cables to diagnose and assure their health condition. Among various testing methods, very low frequency cosine-rectangular voltage (VLF-CRV) testing is a relatively new approach that has been recently proposed because of its significant advantages of high efficiency, multifunctionality, and easy transportability. This article shows the design, implementation, and confirmation of the topology of a novel VLF-CRV generator based on voltage multiplier that avoids separately using HVdc sources and high voltage switches, thus accordingly strengthening its scalability. Note that the mathematical modes of the generator are presented for comprehensive analysis and optimization of the VLF-CRV generator. Simulation in MATLAB/Simulink is performed to validate the generator's feasibility and implementation of a laboratory prototype is also detailed. Moreover, experiments on a capacitor and a medium voltage power cable were performed to confirm the effectiveness of our implementation.