# Study of Partial Discharge Inception Voltage in Inverter Fed Electric Motor Insulation Systems
## 2 Literature Review
### Pulse Width
#### 2.1.3 Summary of Variables Affecting PDIV
** \\ \hline \multirow{3}{*}{Pressure} & Decrease & 5–50/70 mbar & - & \(\downarrow\) air breakdown \(V\) & Range depends on air & [26] \\ \cline{2-7}  & Increase & 100–1013 mbar & - & \(\uparrow\) air breakdown \(V\) & gap and material & [26; 27; 28] \\ \hline \multirow{6}{*}{Humidity} & Decrease & \(>\)50\% & \(V\leq 5\) kV & \multirow{2}{*}{\(V\) insulation permittivity} & \multirow{2}{*}{-} & [20; 29; 34] \\  & Decrease & 10–97\% & \(V\leq 3\) kV & \multirow{2}{*}{-} & [20; 36; 37; 38; 39] \\  & Increase & \(<\)50\% & \(V\geq 5\) kV & \multirow{2}{*}{\(\uparrow\) air breakdown \(V\)} & \multirow{2}{*}{-} & [20; 29] \\  & Increase & 50–97\% & \(V\leq 3\) kV & \multirow{2}{*}{\(V\) insulation permittivity} & \multirow{2}{*}{-} & [39; 26] \\  & & \(T_{\text{amb}}=30\)\({}^{\circ}\)C & & & & \\ \cline{2-7}  & Negligible & 50–95\% & \(V\leq 3.5\) kV & \multirow{2}{*}{\(\uparrow\) air breakdown \(V\), \(\downarrow\) area of PD activity} & \multirow{2}{*}{-} & [38; 26] \\  & & & \(T_{\text{amb}}=25\)\({}^{\circ}\)C & & & \\  & & & \(T_{\text{amb}}=25\)\({}^{\circ}\)C & & & \\  & & & \(T_{\text{amb}}=25\)\({}^{\circ}\)C & & & \\  & & & & \(T_{\text{amb}}=25\)\({}^{\circ}\)C & & & \\  & & & & \(T_{\text{amb}}=25\)\({}^{\circ}\)C & & & \\  & & & & & & \\  & & & & & & \\  & Negligible & 50–95\% & \(V\leq 3.5\) kV & \multirow{2}{*}{-} & [20; 34] \\  & & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\ \hline \multirow{6}{*}{Switching frequency} & \multirow{2}{*}{Decrease *} & \multirow{2}{*}{2–10,000 Hz} & \multirow{6}{*}{-} & \(\uparrow\) space charge due to homo-discharge} & \multirow{6}{*}{-} & [48; 49; 52] \\  & Decrease * & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & Decrease & 2–10,000 Hz & \multirow{6}{*}{-} & [20; 34] \\  & Decrease & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\ \hline \multirow{6}{*}{Rise time} & \multirow{2}{*}{7–1000 ns} & \multirow{2}{*}{7–1000 ns} & \multirow{2}{*}{N overshoot} & \(\downarrow\) time for initial electron generation} & \multirow{2}{*}{-} & [43; 47] \\  & Negligible & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\ \hline \multirow{6}{*}{Rise time} & \multirow{2}{*}{150 ns} & \multirow{2}{*}{7–1000 ns} & \multirow{2}{*}{N overshoot} & \(\downarrow\) time for initial electron waveform \(V\) & \multirow{2}{*}{-} & [26; 45; 46] \\  & Negligible & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\ \hline \multirow{6}{*}{Rise time} & \multirow{2}{*}{7–1000 ns} & \multirow{2}{*}{7–1000 ns} & \multirow{2}{*}{N overshoot} & \(\downarrow\) time for initial electron waveform \(V\) & \multirow{2}{*}{-} & [43; 47; 52] \\  & Negligible & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\ \hline \multirow{6}{*}{Rise time} & \multirow{2}{*}{7–1000 ns} & \multirow{2}{*}{7–1000 ns} & \multirow{2}{*}{N overshoot} & \(\downarrow\) time for initial electron waveform \(V\) & \multirow{2}{*}{-} & [26; 45; 46] \\  & Negligible & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & \\ \hline \multirow{6}{*}{Rise time} & \multirow{2}{*}{7–1000 ns} & \multirow{2}{*}{7–1000 ns} & \multirow{2}{*}{N overshoot} & \(\downarrow\) time for initial electron waveform \(V\) & \multirow{2}{*}{-} & [26; 45; 46] \\  & Negligible & & & & & & \\  & & &