Comparison of passive and active power filters in oil drilling rigs

The Power systems in oil rigs are isolated, standalone systems. The source impedance is low. Bulk of the load is fluctuating nonlinear one and are powered directly from the generators without any series impedance. This paper investigates the harmonic problems, and presents the design of passive and active filter for oil rig power systems. The performance of the system with passive and active filters is studied. The simulation results and actual filed data are presented. Passive filter and active filters are compared in terms of THD improvement, filtering action, VAR rating, size, cost, efficiency and reliability. It is observed that passive filters are suitable where a space constraint is not an issue. In most of the rigs space is a constraint and active filter is the better choice.