An Electric Drive for a Drilling-Rig Top-Drive System

Abstract

This paper is devoted to the possibility of increasing the torque-control range of the top-drive system (TDS) of the drilling rig by using the three-row planetary gearbox in the mechanical channel. By means of electromagnetic couplings, it is possible to direct mechanical energy either through all three rows or through the second and third rows of the gearbox. Thus, it becomes possible to change the gear ratio of the planetary gearbox remotely, which is of outmost importance for a TDS. As a result, it is possible to achieve higher energy indicators of the electric installation when drilling at both small and large depths. In both cases, the engine operates in a mode close to the nominal mode. The use of a reduced transmission also reduces the peak currents when loosening the pipe column. This hypothesis is tested on a mathematical model, in which the electric drive is represented by a converter–motor system with a vector control system. The power consumption is measured at the input of the frequency converter when simulating a large and small load and changing the gear ratio. By optimal ratios when operating in normal mode and in reduced gear, it is possible to achieve an increase in energy efficiency by 4–8.5%, depending on the drilling depth.