Application, design and optimization of hybrid filters for oil drilling rigs

This paper presents the application of hybrid active power filters (HAPF) to mitigate harmonics problems in oil drilling rig system as a case study. In oil rig systems, where majority of the load is non-linear and varying over a wide range, the problems of harmonics are more severe and pose a challenge to the design of a filter which can work effectively at all loading conditions. Passive power filters (PPF) and active power filters (APF) are the main solutions used in the past to address harmonic problems. While the passive filters are not much suitable for varying system conditions, the active filters became popular because of their dynamic nature and high bandwidth operation. But APF still have drawbacks in terms of cost and reliability for its application in high power systems. Of late, HAPF which is a combination of both passive and active filters has gained much attention due to its potential advantages of cost and performance. The challenges in selecting a power filter for a rig system, optimal design of HAPF and its control strategy are presented are given in this paper. The performance is compared with conventional filters under variable load conditions. The simulation results show that HAPF has superior performance compared to conventional filters especially at light load conditions while reducing the overall cost of the system.