## 4 Experimental Results  
Experimental results were obtained by varying pressure from 0.05 to 0.30 MPa and increasing the mixing ratio from 10-30% of base gas and 70-90% of buffer gas. The pressure is varied to determine the gas mixture characterization for medium- or high-voltage switchgear. Based on the results, it is evident that the proposed gas mixture can be utilized for a medium-voltage switchgear system, as it shows promising results at pressure 0.20 MPa or below. The mixing values are varied to determine the optimum mixing ratio, which can be employed in practical applications with dielectric strength comparable to the benchmark SF\({}_{6}\) gas. The insulation performance reliability of the HFO1336 Mzz (E)/CO\({}_{2}\) gas mixtures is assessed by comparing with the benchmark SF\({}_{6}\). SF\({}_{6}\) gas is tested along with all the proposed test gas mixture combinations under the same testing conditions and field configurations. In sphere-plane configuration under AC test voltage of 30%, the base gas mixture at 0.15 MPa shows 1.2 times higher dielectric strength than SF\({}_{6}\). Similarly, the proposed mixture shows 0.9 times dielectric strength for DC voltage compared to SF\({}_{6}\). On the other hand, plane-plane configuration under AC voltage shows \begin{table}
\begin{tabular}{c c c} \hline
**Electrode Configuration** & \
\begin{tabular}{c} **Electric Field Utilization Factor \(\eta\) at** \\ **Constant 6 mm Air Gap** \\ \end{tabular} &
\begin{tabular}{c} **Electric Field Homogeneity Factor \(\alpha\)** \\ \end{tabular} \\ \hline Sphere–plane & 0.74 & 1.34 \\ \hline Plane–plane & 0.95 & 1.04 \\ \hline \end{tabular}
\end{table} 
Table 2: Electric field utilization factor calculation. Figure 7: Electric field intensity of sphere–plane electrode configuration (weakly non-uniform field). 1.60 times and under DC voltage shows 1.15 times higher breakdown strength than SF\({}_{6}\). The detailed experimental results under HVAC and HVDC are discussed in Section 4.1. HVAC Breakdown Characteristics of HFO-1336 mzz (E) Mixture with CO\({}_{2}\)/N\({}_{2}\) under Quasi-Uniform Electric Field  
The HVAC dielectric properties of the test mixtures are comprehensively investigated in terms of breakdown voltages relative to absolute pressure and mixing ratios. The HVAC breakdown properties of the HFO-1336 mzz (E)/CO\({}_{2}\) and HFO-1336 mzz (E)/N\({}_{2}\) mixtures are investigated under uniform and weakly uniform electric field configurations. HFO-1336 mzz (E) has a high liquefaction temperature of 7.5 \({}^{\circ}\)C, so it needs to be mixed with buffer gases such as CO\({}_{2}\) and N\({}_{2}\). The buffer gases N\({}_{2}\)/CO\({}_{2}\) are inert in nature; hence, they de-energize free electrons and help reduce the overall greenhouse gas effect. It is evident from Figure 8a that breakdown voltages of the HFO-1336 mzz (E)/CO\({}_{2}\) gas mixture significantly increase with the increase in applied pressure and mixing ratio. It is because of the significant electro-negativity properties of the proposed gas and the positive synergistic effect between the base gas and buffer gas. Under a quasi-uniform field configuration (sphere-Plane), the breakdown voltages increase nonlinearly with increasing pressure. It is observed that when the HFO-1336 mzz (E) mixing ratio is 20% or more, it has a higher breakdown voltage than SF\({}_{6}\) at a pressure of less than 0.2 MPa. When the pressure increases from 0.2 MPa, the HFO-1336 mzz (E)'s breakdown voltage decreases compared to SF\({}_{6}\). At 0.1 MPa and increasing the base gas mixing ratio from 10 to 30%, the proposed gas breakdown potential increases from 10.5 to 22.4 kV. When the HFO-1336 mzz (E) mixing ratio is 20%, the breakdown increases from 17.6 kV to 29.7 kV from a pressure of 0.05 to 0.3 MPa. When pressure increases from 0.2 MPa, the proposed gas mixture breakdown voltage is less than SF\({}_{6}\), i.e., at 0.3 bar, SF\({}_{6}\)'s breakdown strength is 1.17 times higher than that of HFO-1336 mzz (E)/CO\({}_{2}\).