# Sensor Technologies for Transmission and Distribution Systems: A Review of the Latest Developments
## 5 Key Challenges and Future Research Directions
### Credibility of Data Acquisition  
Sensors facilitate the raw data acquisition of grid parameters through the sensing of various grid components. However, during these acquisitions, the input sensors, especially the source sensor nodes in wireless sensing networks face several issues. First, there is poor management and no security at the input level, which makes the sensor nodes vulnerable to hackers and attackers [153]. Hence, privacy at the input sensing level must be ascertained to maintain the credibility and quality of the sensed raw data. Second, even though the synchronicity among input sensor nodes for wireless sensor networks are maintained \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline
**Power Grid** & **Present Characteristics** & **Future Development Considerations** \\ \hline \hline \multirow{7}{*}{**Transmission System**} & 1. Operator based controls & 1. Automatic controls \\ \cline{2-3}  & 2. SCADA support & 2. Time synchronized measurements \\ \cline{2-3}  & 3. Early integration of RTUs, PMUs & 3. ’Adaptive’ transmission line instruments with multi-level coordination. \\ \cline{2-3}  & 4. Early integration of Wireless Sensing Network & 4. Incorporation of economical energy management techniques and bulk storages. \\ \cline{2-3}  & 5. Sensor based real-time monitoring. & 5. ’Saster-than-real time’ monitoring. \\ \cline{2-3}  & 6. Congestion issues & 6. Switchable network structures to relieve congestion issues. \\ \cline{2-3}  & 7. Uni directional flow of power with early integration and islanding of microgrids & 7. Bidirectional flow of power with transformation to smart grids. \\ \cline{2-3}  & 8. Vulnerable to threats like natural calamities, destabilizing issues, cyber security threats etc. & 8. Incorporation of IoT based real time condition monitoring and predictive maintenance along with cyber security protocols. \\ \hline \hline \multirow{7}{*}{**Distribution System**} & 1. ’Floating’ on transmission line & 1. Distribution automation with advanced distribution management system. \\ \cline{2-3}  & 2. Monitoring and controls restricted to substation & 2. On-site, non-invasive, and active distribution system asset monitoring. \\ \cline{2-3}  & 3. Radial structure & 3. Facilitation of bidirectional power \\ \cline{2-3}  & 4. Limited controllability & 4. Local and autonomous controls \\ \cline{2-3}  & 5. Congestion issues & 5. Switchable network structures to relieve congestion issues. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: A summary of the scope for future developments in transmission and distribution systems with its integration with modern-day sensor technology. through clocks and timers, identity management of each node is still not achieved. This makes the identification and location of faulty nodes in big wireless sensing networks difficult. The identification and naming of sensor nodes is essential since it would help in declaring their availability for efficient utilization of each sensor node, especially during different modes of operations. For example, at any given point in time, some nodes might be in an ACTIVE state, but others might be in SYNCH or SLEEP states, and providing specific addresses to different input sensor nodes would make their differentiation easier [154]. It would also help with the addition of newer sensor nodes into the system that will increase their scalability. Here, scalability means the ability to integrate new sensors to the wireless sensing networks for its expansion in the future. Thirdly, the parameter update policy [3] of the acquired raw grid parameters is not standardized according to the grid conditions. For example, the temporal resolution of electrical parameters during transient grid conditions is supposed to be lower than that in normal grid conditions. Hence, the grid parameters should be updated according to the changing grid conditions. This is essential in capturing the complete profile with all the features of the fault parameters. Finally, there is no accountability for the losses in sensors.