Impact of Nonlinear Loads on Leakage Protection in Vietnamese Mine Networks

The current leakage protection relays in Vietnam's underground mining are design and operate under the current and voltage conditions of the sinusoidal electrical network. However, in recent years, many nonlinear loads have been equipped and used in underground mine electrical networks, which makes the voltage and current in the mine electrical network no longer sinusoidal. The consequence of that causes the mistaken impact of the leakage protection relay, leading to unsafe mining operations. In addition, quantitative analysis studies of the impacts of nonlinear loads on the operation of the leakage protection relay in the mining power grid in Vietnam are still lacking. The content of the article is to study, evaluate, and analyze the influence of nonlinear loads on leakage current in the mine electrical network. The research results are analyzed on the basis of theory and evaluated on the simulation model using Matlab - Simulink software. The results in the article are also the scientific basis for equipping and adjusting the leakage protection relay appropriately, thereby improving safety in mining in Vietnam.