On the matters of increasing the dependability of first stage pumping stations power supply

Abstract

First stage pumping stations are first category power consumers that usually have back-up power supply. Additionally, the engine room of the pumping station is equipped with synchronous or asynchronous high-voltage motors that in transient states may create unforeseen problems in the power supply system not only within the station, but beyond. The dependability of plant and equipment is defined by many factors, e.g. start-up procedures, stopping-down, operational changes, equipment shutdown. [6]. The primary factors that reflect the impact of the transient states are mechanical overload, voltage slumps in load centers, voltage slumps in switchgear busbars, etc. The value of voltage slump associated with start-up of high-voltage synchronous motors that does not last more than 30 seconds is neglected, though the impact of start-up voltage slump is a negative factor that affects adjacent consumers on the grid [7]. The dependability of the power supply system has an effect not only on pump station operation, but also on the service life of the facility’s electrical equipment. An undependable power supply system can also contribute to higher electric loss and deterioration of power quality. Improving the dependability of power supply systems of the considered facilities requires first and foremost specific tasks to be solved. To that effect, this article specifies and analyzes primary causes of faults in first stage irrigation pumping plants. The authors clarify the dynamic stability of high-voltage synchronous motors and its dependence on short interruptions of power supply. They also analyze the impact of start-up currents of synchronous motors on the operation of pumping units and electrical equipment in general. The article substantiates the efficiency of soft starters (SSs) in start-up procedures of high-voltage synchronous motors of pumping units of irrigation pumping stations. The article also establishes the inefficiency of frequency converters in pumping units of irrigation pumping stations using specific examples. It was found that automatic transfer equipment in the considered facility does not ensure the speed of operation required for fault recovery and negation of water hammers in pumping units. The article sets forth the tasks and possible solutions related to improving the dependability of power supply systems of first stage irrigation pumping plants.