## 3 Development of Thermal Condition Monitoring System
### Overview of WSNs and Communication Links Characteristics
#### 3.3.1 Attribution of Emerging Wireless Communication Links  
Modern DERs grid integration monitoring and control requires communication between different components to enhance the reliability of grid functions. This demands a reliable range communication protocols for a guaranteed performance. The emergence of wireless communication technologies for distributed grid operation proposes various functioning characteristics with their pros and cons [65]. The concerns of wireless connection for DERs performance present comprehensive benefits with some drawbacks [66], which influence the general communication requirements of smart grid application deployment. WSNs are maturing technologically and in the practice of field applications for physical parameters and also intelligence to transmit signal wirelessly. These present measurement indications in their performance context for operational readiness [65; 67]. They exhibit potentials of development in scientific and industrial communities, thus reinforcing the beliefs that new paradigm of sensing applications are gaining resiliency. Accordingly, the low-power wide-area network (LPWAN) has emerged as a WSN-based technology that adds to the wireless communication solutions [67]. Gradually, its addition seeks to enhance industrial wireless sensor applications and deployment. Particularly, the technology is poised for much development concerning asset management in wide coverage areas of monitoring and controls for processing and production plants. It does propose to improve operation and performance reliability. This means the application could beuseful to distributed energy systems in the context of operational technology for a smart grid concept. The main characteristics are its excellent long-range, low-power consumption, and reduced computation capacity [65; 68; 69]. Although cable-based networked communications are sometimes an infeasible resolution, however due to their complexity in installation and maintenance, their presence in industrial monitoring and controls are still being accommodated until they are completely phased out. In distributed energy systems with high penetration for renewables distributed generation units, connecting at different voltages and power levels make the evolution of wireless technology proposal significant in all performance [65; 66; 67]. This proposes a solution to performance assurance to overcome the operational deficiency as a result of cable breakdown and other lapses in variables indications. The LPWAN encompasses group of technologies, allowing wide area communications at low cost points and reduced power consumption. LPWAN technologies have arisen in both licensed and unlicensed frequency band allocations, such as long range (LoRa), Sigfox, and Narrow band (NB)-IoT/LTE-M [67; 70]. The NB-IoT and LTE-M are considered to be of inter-linked communication, per the spectra band. Amid the LPWAN applications, LoRa and NB-IoT/LTE are the most projecting ones, although they plainly exhibit different technical characteristics. LoRa can operate in both licensed and unlicensed bands however; there are limitations in some countries for acceptance due to signal performance hitches on the ISM band deployment. Unlike LoRa, an NB-IoT/LTE network deployment requires setup on existing cellular network [69; 70]. This makes LoRa a more flexible solution than NB-IoT/LTE to meet the requirements of outlying decentralized network and reaching out to grass root levels where applicable. It is worthy to consider how LoRa is convincingly becoming the main actor in the current LPWAN scene, in deployable areas as it applications operates on an unlicensed spectrum below 1 GHz and also supported by more world leading communication technology entities. From a technological viewpoint, LoRa offers a proprietary chirp spread spectrum (CSS) modulation to achieve greater communication ranges.