Digital Control of Electric Power Flows in Unbalanced Distribution Networks as Part of The Automated Metering and Control System

Abstract

This paper aims to address the problem of controlling the electricity flows in power distribution networks (PDN) operating under current and voltage unbalance. As is known, the unbalance factor is responsible for significant losses of active power and, therefore, is detrimental to the PDN efficiency and technical and economic performance. The purpose of control is to minimize technical power losses in the distribution network. This is to be achieved by building an information control system (ICS) for balancing a three-phase network as part of the automated metering and control system (AMCS). The latter is currently being widely adopted to automate information processes in PDNs. However, the AMCS does not include technologies for solving the problem in question. We propose an algorithm of the digital controller operation for the ICS. Its primary function is to maintain phase power at a given level in real-time. The algorithm concept is based on the idea of required redistribution of electricity flows between the phases of the distribution network by appropriately switching single-phase loads of consumers (users) to ensure a minimum spread of phase powers relative to their required level. To achieve the goal of control, we construct criterion functions that determine qualitative indices of the ICS operation and develop computational schemes for their minimization. Control actions to be generated by the digital controller and performed on the facility represent a digital code that contains data on the coordinates of three-phase network loads to be switched to another phase.

Development Issues of Systems for Automation and Digitalization of Power Distribution Networks

“…where P is a discrete admissible subset; p * is an optimal desired vector. An algorithm for solving the extremevalue problem ( 2) is proposed in [8].…”

“…From a technical perspective, the IС subsystem is implemented by means of a digital controller (DС) [8,31], the structure of which is shown in Fig. 3.…”

“…This control signal u * is transmitted to the actuators of the system through the communication channel (CC). Such actuators are phase current switches (PCS) designed to carry out the required switching of loads of network consumers from one phase to another [7,8]. The phase current switch (PCS) is implemented on the basis of a separate microcontroller unit.…”

“…. Methods, algorithms, and technologies for the construction of the IC subsystem are proposed in [7,8].…”

“…The practice of their use has shown that they fail to adequately ensure the desired level of electricity losses, since these automated systems are mainly designed for electricity revenue metering. Analysis indicates that to significantly reduce electricity losses in the PDN it is necessary to additionally perform the optimization of operating conditions of facilities [5][6][7][8], diagnostics of critical states of distribution grids [9][10][11], including the identification of places of unauthorized consumption (theft) of electricity [12][13][14], and the monitoring of electricity losses [15,16] in real time. The existing (conventional) ASEMMs do not address this set of tasks.…”