DEVELOPMENT AND CONFIGURATION OF A FULL-ORDER OBSERVER FOR «CABLE LINE – INDUCTION MOTOR» ELECTRICAL COMPLEX

Abstract

Link for citation: Rakov I.V., Glazyrin A.S., Kladiev S.N. Development and configuration of a full-order observer for «cable line – induction motor» electrical complex. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 10, рр. 219-231. In Rus. The relevance. The task of oil production specialists is to minimize all types of energy consumption, ensuring an increase in oil production profitability because of the following reasons. First of all, availability of oil reserves with low energy consumption decreases, and the number of gushing wells reduces, along with increase in water content in the extracted liquid. One of the methods of reducing energy consumption in wells with low and moderate flow rate, equipped with electric submersible pumps, is a well transfer from continuous to periodic operation mode, namely cyclic well operation. This involves alternating short periods of oil production (up to 15 minutes) with liquid accumulation (up to 30 minutes) in the wellbore. Well switching to a cyclic operation mode leads to a 40 % reduction in electric power consumption by the submersible electric motor, as well as increase in oil production up to 3 %. This can be achieved by partial gravitational separation of the extracted liquid at the accumulation stage. However, a negative consequence of switching to a cyclic operation mode is a reduction in an average time between failures. This is due to increase in current surges and torque during rapid acceleration of the submersible electric motor to the rated speed. Transition from a scalar control system with an open loop to a vector control system without sensors can settle these problems. To implement a vector control system, it is necessary to obtain information about the state variables of a submersible electric motor. Construction of a full-order observer based on explicit mathematical models is considered as a promising method of obtaining information, taking into account the main advantages and disadvantages of direct measurement and indirect estimation of state variables. Based on the above, the urgent task is to develop a full-cycle observer for the electromechanical complex «cable line – induction motor» and a methodology for its configuration. The settlement of this issue will create prerequisites for implementation of a vector control system by a submersible electric motor. The main aim: to develop and experimentally validate the effectiveness of a full-order observer for the electrical complex «cable line – induction motor» using voltage and current measurements at a cable line input. Methods: literature analysis, system analysis, mathematical modeling, experimental research. Results. The authors have developed and tested a full-order observer for the «cable line – induction motor» electrical complex. The results of this study confirm the efficiency of the developed observer and its potential applicability for implementing a vector control system for electric submersible pumps. Ultimately, this will enable the transition of low- and medium-flow-rate oil wells to a cyclically operated mode without a significant reduction of the mean time between failures.