## 4 Results and Discussion
### Transformer Condition Monitoring
#### 4.8.4 Partial Discharges
This noted rise suggests that more people are becoming aware of the potential benefits of IoT technology for transformer monitoring. The largest shift occurred in 2022 when there was a noteworthy increase of 25.8% of studies published. This spike can be attributed to the increasing availability of implementation tools and data, as well as the expanding awareness of IoT applications. There seems to be a lot of interest among researchers and practitioners in the idea of using the IoT to enhance transformer status monitoring. The trend in growing interest and research activity in IoT technology for transformer monitoring is evident from these data. It suggests that researchers, industry professionals, and other interested parties are beginning to understand how the IoT might fundamentally change how electrical transformers are serviced, maintained, and optimized. As technology advances, this trend is probably going to continue, leading to more inventive uses and solutions in the years to come. RQ 6: What emerging opportunities and technological advancements are highlighted in the collected literature that may shape the future of transformer monitoring using the IoT? Figure 13: Research distribution by communication channel. The collected literature focuses on a number of recent innovations and technological advances that may have an impact on transformer monitoring via the IoT in the future. Among them are the following:  
* Several studies discuss the use of advanced sensors and data collection tools to capture data in real time from transformers [65]. Improved monitoring and diagnostics may result from the more complete and accurate data collection provided by new sensor technologies, such as optical sensors. * Studies show that machine learning, AI, and deep learning algorithms are being used more and more for defect identification and data analysis [22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 39; 40; 41; 42]. Improvements in fault prediction and classification made possible by these developments enhance transformer monitoring. * A few works address the application of edge computing for data processing and analysis [34]. In situations where cloud connectivity may be limited, edge computing can reduce latency and enhance real-time monitoring capabilities. * Cloud-based solutions are mentioned in some research. The scalability, storage, and data-processing capabilities of cloud computing can facilitate large-scale IoT deployments and data analytics. * Internet of Things technology is crucial for managing the whole transformer lifetime, from design and manufacture to operation and maintenance, according to the literature [36]. By using a comprehensive approach, transformer performance can be optimized, and their lifespan can be increased. * Maintaining the cybersecurity of IoT systems is essential given the growing connectivity and data sharing [28]. A few articles address the use of cybersecurity to safeguard infrastructure and data related to IoT technology. * Several studies focus on improving energy efficiency through IoT technology [117]. Optimizing transformer operation and reducing energy losses are key objectives, contributing to sustainability efforts. RQ 7: Which transformer types does the collected literature investigate? Figure 14: Research evolution over a decade. The gathered literature explores a range of transformer types, representing a variety of uses and research interests in the topic of electrical transformer monitoring. Figure 15 illustrates that 49 percent of studies concern the \"Power Transformer\", the most often studied transformer type in the literature. This implies that power transformers, which are essential parts of electrical power systems, are the subject of a significant amount of research, with 40.8 percent of publications focusing on distribution transformers. The significance of guaranteeing dependable energy distribution is in line with the research interest in transformer monitoring, as these devices are essential to power distribution networks.