Energy Processing and Smart Grid

CHAPTER 16SMART-GRID LAYERS AND CONTROL

16.1 INTRODUCTION

This chapter aims to evaluate various control systems involved in a smart grid. The layers of a smart grid, including the physical, real-time measurement, communication, application, and cost–benefit analysis will be comprehensively reviewed. State-of-the-art tools for control and communications are evaluated, as are related issues and challenges. Smart grid as a case study of a cyber-physical system will also be described.

16.2 CONTROLS FOR THE SMART GRID

Smart-grid control is important so that the following can be achieved:

• New micro sources can be integrated into the system without modification of existing equipment.
• The microgrid can choose operation point independently.
• The microgrid can connect to or island itself from the traditional grid quickly and seamlessly.

A key element of smart-grid operation is the grid energy management system (EMS). It includes control functions that define the grid as a system that can manage itself, operate autonomously or grid connected, and seamlessly connect to and disconnect from the main distribution grid for the exchange of power and the supply of ancillary services.

Hierarchical levels of control for micro grids may be categorized as primary, secondary, and tertiary, Figure 16.1. Primary control is the level in the control hierarchy that is based exclusively on local measurements, which includes islanding detection, output control, and power sharing (and balance control). ...