# A Low-Cost Secure IoT Mechanism for Monitoring and Controlling Polygeneration Microgrids
## 2 Related Work  
A microgrid is a group of interconnected loads and distributed energy resources within a defined electrical boundaries [16]. Traditionally, microgrids have been used in remote areas without access to main power grids and can employ various communication technologies to data sharing. In addition, the governments in the U.S., the Asia Pacific region, and the European Union have established supporting policies, demonstration projects, control systems research, and the development of software tools for microgrids. For instance, The U.S. federal government provides investment tax incentives for customers installing microgrid technologies. The incentives cover a wide range of technologies including solar photovoltaics, combined heat and power, and electric vehicles. Some states provide incentive for microgrid projects to supply individual customersor critical loads such as hospitals, first responders, and water treatment facilities, after natural disasters such as Hurricane Sandy [17]. However, given the intermittency and variability of RES, microgrid customers need mechanisms for controlling power demand depending on power availability. Therefore, the U.S. Department of Energy has identified several core areas for microgrid controls: (1) frequency control; (2) volt/volt-ampere-reactive control; (3) grid-connected-to-islanding transition; (4) islanding-to-grid-connected transition; (5) energy management; (6) protection; (7) ancillary service; (8) black start; and (9) user interface and data management [18]. Wireless Sensor Networks (WSN) are used in area monitoring, threat detection, the domestic sector, health care sector, environmental sector, industrial sector, and the primary sector. A WSN is defined as a self-configured and infrastructure-less wireless network of spatially dispersed sensors dedicated to monitoring and recording physical conditions of the environment [19]. A WSN can have a few to even thousands of nodes, where each node is connected to one or many sensor nodes to cooperatively pass their data across the network to a main location (usually a data center). Each sensor node is typically composed of a radio transceiver with an internal or external antenna, a micro-controller, an electronic circuit interfacing with the sensors and an energy source. WSNs topologies can vary from a simple star topology to a multi-hop wireless mesh topology [20]. Size and cost constraints on sensor nodes result in corresponding constraints on resources such as energy, memory, computational speed, and communications bandwidth. Moreover, a WSANCS is composed of a group of distributed sensors and actuators that communicate through wireless link which achieves distributed sensing and executing tasks [21]. This latter scheme allows the distributed control of devices that are spread in a wide area without physical connections between them such as a polygeneration distributed system with several renewable energy sources. A WSANCS connected to the Internet becomes an IoT system. [PERSON] [22] illustrated the integration of the IoT for monitoring tasks in the office sector. They showed the convenience of having a monitoring system for conserving energy. A similar application was implemented by [PERSON] [23], who demonstrated the potentiality of having a smart home monitoring system. However, the use of this communication technology puts at risks the security and privacy of the data. IoT uses the Internet, thus carrying its vulnerabilities. These systems are vulnerable to diverse types of attacks such as denial of services, packet sniffing, and session hijacking to the confidentiality, integrity, and availability of the system, both damaging the system and putting the user to a possible personal risk [24; 25]. In [26], [PERSON] described that 70% of the most popular IoT devices have vulnerabilities. Additionally, more than 25 vulnerabilities per device were discovered on average, with a total of 250 security concerns across all products tested.