# A Review of Health Assessment Techniques for Distribution Transformers in Smart Distribution Grids
## 5 Conclusions
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Monitoring Techniques** & **Monitoring Parameters** & **Advantage** & **Disadvantage** \\ \hline \multirow{4}{*}{6} & Online distribution service & 1. Top oil temperature & Reliable & \\  & transformer health & 2. Vibration & Low cost, only use Energy meter & Further studies needed to \\  & assessment using real-time & 3. Transformer loading & High time resolution (1 s) & improve the precision \\  & grid energy monitor [88] & 4. Power factor & No need to add sensors & \\ \hline \multirow{4}{*}{7} & Multi-source information & 1. Voltage deviation & Higher accuracy & \\  & analysis (statistical data, text mining) [89] & 2. Load rate & Low cost, only use Energy meter & Need conventional test data (Unbalance and Harmonic \\  & & 3. Unbalance factor & No need to add sensors & distortion) \\  & & 4. Harmonic voltage distortion & & \\ \hline \multirow{4}{*}{8} & Transformer Fault Diagnosis & 1. DGA & \multirow{2}{*}{Very high accuracy} & Need to use many parameters \\  & based on Multi-source & 3. Special sensor real-time data & Can predicting the location, & \\  & Information Fusion [90] & 4. Related electrical test data & type and property of & high accuracy and they need to \\  & & 5. Operation and repair records & transformer faults. & use many types of historical \\ \hline \multirow{4}{*}{9} & Leveraging advanced & 1. Transformer loading & \multirow{2}{*}{Comfortable for utility to monitor and set up suitable} & Need to install many of smart \\  & Leveraging advancement & 3. Estimated Ambient & monitor and set up suitable & meters that be installed at \\  & (AMI) [91] & temperature & asset management plans. & customer locations for each of \\  & (AMI) [91] & 4. Computed hottest & Time resolution (1 h) & distribution transformers \\  & & temperature & & \\ \hline \multirow{4}{*}{10} & Advanced Metering & 1. Customer Information System & \multirow{2}{*}{Can collect the loading data of all areas.} & Need to install many of smart \\  & Infrastructure (AMI) [49] & 2. Transformer loading & \multirow{2}{*}{Can collect the loading data of all areas.} & \multirow{2}{*}{There at customer side} \\  & Infrastructure (AMI) [49] & 3. Weather data & & \\ \hline \multirow{4}{*}{11} & Smart Transformer & \multirow{2}{*}{1. DGA } & \multirow{2}{*}{Investing Advances} & \multirow{2}{*}{Investing Advances} & \multirow{2}{*}{Investing Advances} \\  & & 2. Temperature & Comfortable for utility to monitor and set up suitable & \\  & (AMI) and Advance & 4. Real-time loading & asset management plans. & customer locations for each of \\  & (ASI) [80] & 5. Electrical parameters & & \\ \hline \multirow{4}{*}{12} & Wireless Partial Discharges & \multirow{4}{*}{1. Voltage pulses} & Wireless & \multirow{2}{*}{Devoted to dielectric health only} \\  & & & Small physical dimension & \\ \cline{1-1}  & & & Portable & \\ \cline{1-1}  & & High accuracy & & \\ \cline{1-1}  & & No sensors needed & & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: _Cont._these benefits and the pressure utilizing the existing assets under a competitive environment, real-time monitoring is now a hot topic to power system managers and engineers as well as researchers. Research in recent years clearly shows that advanced signal processing techniques and artificial intelligence techniques are indispensable in developing novel real-time monitoring systems. Benefiting from the development of computer techniques and communication techniques, signal processing and AI have become the most powerful tools to make next-generation real-time monitoring equipped with high levels of sensitivity, reliability, intelligence, and cheapness. Conceptualization, Q.T.T. ; writing--original draft preparation: Q.T.T., P.W., J.J.; writing--review and editing, Q.T.T., P.W., J.J., K.D., L.R., E.R.S. and G.Z. ; supervision, L.R. ; project administration, L.R. and K.D. All authors have read and agreed to the published version of the manuscript.