A Model Predictive Control Strategy for Distribution Grids: Voltage and Frequency Regulation for Islanded Mode Operation

Abstract

In the last few years, one of the most important challenges of power technologies has been the integration of traditional energy production systems and distributed energy resources. Large-scale photovoltaic systems and wind farms may decrease the quality of the electrical grid service, mainly due to voltage and frequency peaks and fluctuations. Besides, new functionalities, such as the operation in islanded mode of some portions of the medium-voltage grid, are more and more required. In this respect, a model predictive control for voltage and frequency regulation in interconnected local distribution systems is presented. In the proposed model, each local system represents a collection of intelligent buildings and microgrids with a large capacity in active and reactive power regulation. The related model formalization includes a linear approximation of the power flow equations, based on stochastic variables related to the electrical load and to the production from renewable sources. A model predictive control problem is formalized, and a closed-loop linear control law has been obtained. In the results section, the proposed approach has been tested on the Institute of Electrical and Electronics Engineers(IEEE) 5 bus system, considering multiple loads and renewable sources variations on each local system.

Distribution Grid Stability—Influence of Inertia Moment of Synchronous Machines

“…Under the permissible load angle oscillation amplitude β A = 0.1 rad (equal to the overflow of active power P a = 20 kW), the intersection point P presented the maximum value I = 160 kg•m 2 .…”

“…Grid frequency oscillation has a random noise trend because it is only the response of an energy system to a casually changing daily demand energy diagram [1]. This effect is particularly significant in microgrids [2][3][4]. The issue of network stability has been studied in a number of other works (e.g., [5]).…”

A Comprehensive Virtual Synchronous Generator Control Strategy for Harmonic and Imbalance Voltage Suppression of Multi-Inverter Parallel Microgrid

“…Ref. [21] proposed a closed-loop control law for linearization and control. The model is used to adjust the power through the model to change the grid voltage and frequency, thereby improving the quality of the system.…”

Disturbance Observer-Based Offset-Free Global Tracking Control for Input-Constrained LTI Systems with DC/DC Buck Converter Applications

“…If the control objective is to stabilize the system, the problem is easy to solve since zero input is a feasible stabilizing control owing to the open loop stability of the system. However, if the feedback control aims to achieve the offset-free tracking for the uncertain input-constrained system, the problem is not trivial [1][2][3][4][5].…”