# Design of a Partially Grid-Connected Photovoltaic Microgrid Using IoT Technology
## 1 Introduction  
Electric power systems have been developed over the past century until they became integrated systems in terms of planning, management, operation, and control. These systems are characterized by central bulk power generation power plants connected to consumers through high-, medium-, and low-voltage transmission and distribution networks. This complex power system forms the backbone of modern human civilization. The existing infrastructure uses strategies and technologies that were developed many decades ago, which utilize limited control and digital communication technologies of the 21 st century [1]. Moreover, climate change concerns and environmental issues urged many countries to adopt new strategies for reducing the dependency on fossil fuels to reduce carbon dioxide emissions. Clean energy production is achieved through enabling renewable energy generation and integration into electrical energy systems. Power systems need to meet changes in generation profiles to create intelligent tools that rely on advanced sensors, ICT (information and communication technologies), and digital control technologies that can distribute electricity effectively, economically, and securely. Renewable power integration can provide many advantages such as lowering cost and increasing system reliability, power quality, and energy efficiency [2, 3]. The integration of renewables is achieved in the form of either mega-sized renewable energy parks connected to the main grid or small-sized units connected to distribution systems. Besides these,other forms of distributed small-size energy resources include fuel cells, microturbines, reciprocating engines, storage systems, and controllable loads. Such power generation resources require power-electronic interfaces, communications, and control systems to deal with and dispatch within the constraints of the uncertainty of renewable generation [4]. The concept of a Smart Grid has emerged as the vision of the future generation of power systems [5]. The smart grid's attributes can be summarized in the following [6]: (1) optimal cost electricity generation considering dispatchable demands, (2) maximizing low-carbon generation, (3) resiliency of both physical and cyber-attacks, (4) ensuring the best power quality for consumers, and (5) monitoring of components and devices to prevent component outages or even system blackouts. It is important to mention herein that the cost of an electric system blackout is very high and results in severe economic and social impacts [7]. Smart grid enabling requires innovative solutions and technologies that include digital smart meters, sensors, actuators, controllable charging, intelligent circuit interfaces, phasor measurements units, communication systems, cloud computing, wide and local area controllers, home automation, etc. [8]. Smart grid technologies and associated infrastructures continue to grow tremendously, which requires associated approaches and methods to improve system performance and energy efficiency [9]. Demand response (DR) is the most economical and reliable solution for smart power systems [9; 10; 11; 12]. The IEEE Std. 2030.6-2016 defines the DR as: _The participation of customers in electricity markets by changing their electricity consumption patterns in response to the price signals or incentive mechanisms from DR service providers._[13]. The DR implementation allows the use of electricity with changes in the customer's load profile according to their needs. Also, it allows dealing with the variation of renewable energy sources (RES) generation [14]. The DR implementation is relying on advances in ICT [15]. The DR implementation offers many opportunities for market agents to provide cost-effective solutions [14; 16]. Demand response programs involve a series of control strategies to fulfill both end-users as well as specific requirements. In a typical DR scheme, a balancing strategy could be implemented to provide load flexibility during stress periods of the grid.