## 2 Application of Wireless Sensor Networks in Smart Grid  
WSN is a cost effective solution for monitoring, control, measurement and fault diagnosis in various domains of smart grid network. A sensor node mainly contains sensors, memory, processor, power supply, transceiver and actuator. Sensors are used to sense various quantities like humidity, temperature, current, etc. Generally, WSN nodes are battery powered. Figure 1 shows the basic structure of WSN node. WSN facilitates both sensing and communication requirements [21; 22; 23]. Small sensor nodes collectively form a sensor network which is used for remote wireless communication in HAN, NAN and WAN [21]. Large scale deployment of sensor nodes can be used to communicate the conditions of various generation, transmission and distribution units. Wireless sensor nodes can provide economical solution for smart microgrid monitoring which facilitates high penetration of renewable energy sources. WSN is a significant part of advanced metering infrastructure (AMI). Sensing and communication are crucial for Plug in Hybrid Electric Vehicle (PHEV) system which is one of the most ingenious component of smart grid technology. PHEV contains gasoline or diesel engine with an electric motor as well as a large rechargeable battery. PHEV can be recharged from an electrical  
Figure 1: Architecture of WSN (Wireless Sensor Network) node. power outlet. It has the potential to reduce Green House Gases (GHG) emissions and carbon footprint [38; 39; 40]. PHEV facilitates flexibility as well as economy in fuel usage [41; 42; 43]. WSN can be used to communicate PHEV statistics to upstream network layers for operation and control of Smart Grid components. This information will be online available to various stakeholders through a web of sensor nodes [44; 45; 46; 47; 48]. An effective remote monitoring, diagnosis and control can prevent cascaded disastrous events and breakdowns [49; 50; 51]. Wireless sensor networks can be used for accurate monitoring of generation, transmission, distribution and consumption of electricity [52; 53; 54; 55]. WSN is the most suitable solution for HAN, NAN, WAN and smart microgrid applications for integration and operation of renewable energy sources [54; 55; 56; 57; 58; 59]. Figure 2 shows the application of WSN at different levels of smart grid. Wireless sensor networks are applicable for the following smart grid utilities:  
* Smart power generation  
Wireless sensor networks can be used at the generation side for monitoring and management of produced energy. It is a prominent solution for smart microgrid applications using renewable energy resources. WSN can be used in solar farm, wind farm, biogas plant, etc. to monitor and control intermittent energy. One of the objectives of smart grid is to expedite the use of renewable energy sources. Renewable energy resources are situated in harsh environments and hostile locations. Moreover, their unpredictable behavior creates more challenges during their operation and management. WSN nodes are economical solutions for monitoring the behavior of renewable energy resources [55; 56; 57; 58]. Various parameters of generating equipment can be effectively measured, communicated and controlled using WSN. * Smart power transmission and distribution  
Transmission and distribution of power contains various components like overhead transmission lines, underground cable network, substations and distribution transformers. WSN is an essential element of SCADA system. Real time remote monitoring of these components is  
Figure 2: Application of WSN in smart grid hierarchical architecture. inevitable to prevent power failures due to equipment breakdown or malicious attacks. Wireless sensor networks can be used for power monitoring, fault detection and isolation, location discovery and outage detection [56; 57; 58; 59]. * Customer applications  
Wireless sensor network is an effective and prominent solution for home automation systems. It can be used for complete energy management of customer premises.