Multivariable Hybrid Control System of the Distribution System Power Factor

Abstract

Existing mathematical models of electric distribution systems containing a group synchronous motors considered as a reactive power control object do not take into account the influence of synchronous electric motors on each other through a common power source, which negatively affects not only control errors but also the possible reactive overload of the individual motors. In this paper, a multivariable plant model of an industrial electric distribution system with a group of two synchronous motors with the common and individual field windings DC power source was derived and a reactive power coefficient feedback control system was proposed. The control system provides two separate reactive power control channels with the excitation current control loop interacting in the torque angle variables for each of the motors in the group. The parameters of the reactive power coefficient regulator are selected taking into account the interaction of the control channels, which reduces the value of the system stability margin by 25–30%. In the case when the reactive power supplied by the controlled synchronous electric motors is not enough the control system provides additional control channel that activates a capacitor bank, which helps to maintain the value of the reactive power coefficient within the normative limits. The control system has been verified using MATLAB/Simulink simulation models and partially validated in a field test on the distribution system of the oil field cluster pumping station Barinovskaya, JSC Samaraneftegaz. The proposed power factor control system can be effectively used in industrial distribution systems operating with a significantly variable power consumption mode incorporating high power synchronous drive.