Research of the optimal method of control of the first rise pumps electric drives operated in conditions of negative temperatures

Abstract

OBJECT. The work is aimed at solving an important problem of increasing the economic efficiency, the level of resource saving and accident-free operation of the first rise section of the centralized water supply systems of small and medium-sized settlements. At the same time, the task is to minimize the cost of electricity associated with the excess performance of pumps, while ensuring the protection of the pipeline from freezing in conditions of negative ambient temperatures. METHODS. To solve this problem, an optimal method for controlling electric drives of first rise pumps at the request of the end user of water was developed, which differs from the existing ones by analyzing the state of the thermal parameters of the pipeline. The method is based on the calculation of control actions based on the water level in the storage reservoir or the water pressure in the pipeline UL and the water temperature at the end of the pipeline UT, followed by the calculation of the optimal pump supply setpoint, which is then maintained by the frequency control method. The Matlab® Simulink simulation model was used to determine the optimal laws for calculating control actions and evaluate the effectiveness of the proposed solutions. RESULTS. Based on the simulation results, it was found that it is advisable to use the PID law for calculating the control effect for the UL level, the PD law for the UT temperature, and the PI law for the flow rate. The parameters of the technological process and the level of power consumption in the control process were also evaluated. CONCLUSIONS. Studies of the proposed concept of managing the first rise section have shown high technical and economic efficiency, in particular, the savings in electricity consumption are estimated at about 22 % while ensuring the protection of the pipeline from freezing.