DISADVANTAGES OF LOCK UNDERVOLTAGE PROTECTION AT OIL PUMPING STATIONS

Abstract

This article examines the effectiveness of the blocking action for the undervoltage protection from the overcurrent protection in electric mains pump stations and analyzes the impact of non-selective action of the undervoltage protection on the technological process of pumping. The process of pumping oil through main pipelines is continuous. However, when power failure, the motors of the main pumps lose power, that can disrupt the continuity of the technological process of pumping. The protection from power loss are used to detect power failure and taking measures to preserve the continuity of the technological process at oil pumping stations. Undervoltage protection is the main power loss protection when asynchronous drives of the main pumps are used on oil pumping stations. The undervoltage protection must not operate when short circuits in the distribution network of the enterprise to ensure the selectivity of the action. Disable entire section tires switchgear may take place if non-selective trigger occur. It can lead to the stop of the main pumping units and to the total breakdown of the process of pumping oil through the pipeline. Therefore, the protection of the minimum voltage should be blocked when the short circuits in the electrical network of the enterprise. Lock protection minimum voltage at the booster stations is performed from an overcurrent protection input. It isshown that depending on the mode of the supply network lock maximum current input protection may not be effective and undervoltage protection may work selectively. Found resistance range electric supply the range of distances to the fault location at which the failure of MTW and non-selective tripping MNH, at PS, the Investigated transients in the pipeline in the non-selective protection of the minimum voltage. It is shown that depending on the mode of the supply network the blocking may be not effective and undervoltage protection may work incorrect. Found resistance range of electric supply network and the range of distances to the fault location at which an overcurrent protection is not work but undervoltage protection works. Investigated transient processes in the pipeline when protection of the minimum voltage acts not selective.