## 3 Simulation Results and Experimental Validation
### Simulation Results and Experimental Verification
(**b**) is the temperature drop process of the ZnO varistors. Figure 9: The influence of different current amplitudes on \(\beta\). The currents of columns 1, 2, and 3 increase sequentially. According to the thermal effect of current flowing through varistor, the column with a higher current accumulates more heat and the temperature rises faster for the same structure. The temperature rise of the ZnO varistor increases sequentially as well. Combining the experimental results in Figures 10 and 11, the experimental results are in accordance with the theoretical analyses. The lowest temperature in column 2 in Figure 10 is due to the special measurement point chosen. The column 2 ZnO varistor's temperature measurement points are 2-5, as shown in Figure 8. This ZnO varistor is relatively close to spacer II-II. Due to the significant difference in the conductivity of the materials, the rise in temperature of the ZnO varistor is greater than that of the spacer. It promotes the temperature transfer between the ZnO varistor and the spacer. During the temperature rise, the temperature of the ZnO varistors near the spacers is lower, and their temperature away from the spacers is higher. Placing spacers around the ZnO varistors can reduce the temperature rise and improve their reliability. The time for the temperature to be lowered to room temperature is about 300 min. The simulation results show that the temperature of the three ZnO varistors decreases from 76.60 \({}^{\circ}\)C, 62.90 \({}^{\circ}\)C, and 80.50 \({}^{\circ}\)C to 20.00 \({}^{\circ}\)C. The experimental results show that the temperature of the three ZnO varistors decreases from 74.39 \({}^{\circ}\)C, 62.41 \({}^{\circ}\)C, and 76.30 \({}^{\circ}\)C to 20.80 \({}^{\circ}\)C. The temperature of the ZnO varistor in column 2 is low, and the descent process is gentle. In Figure 10, the simulation results agree with the experimental results. The maximum error of the ZnO varistor in column 1 is 2.98% at 14 min. The maximum error of column 2 ZnO varistor is 4.30% at 14 min. The maximum error of the ZnO varistor in column 3 is 4.60% at 14 min. From the simulation results of the spacers, the maximum temperature of column 1 is 48.50 \({}^{\circ}\)C, the maximum temperature of column 2 is 45.70 \({}^{\circ}\)C, and the maximum temperature of column 3 is 42.90 \({}^{\circ}\)C. From the experiment results of the spacers, the maximum temperature of column 1 is 47.34 \({}^{\circ}\)C, the maximum temperature of column 2 is 44.12 \({}^{\circ}\)C, and the maximum temperature of column 3 is 41.76 \({}^{\circ}\)C. In both the simulation and experimental results, the maximum temperature of the column 1, 2, and 3 spacers increases sequentially. This is based on the current in Figure 9. The temperature of the column ZnO varistor with a high current is higher. The temperature difference between the adjacent ZnO varistor and the spacer is even greater. The ZnO varistor and spacer have more heat conduction energy. The temperature of the spacer is higher, and the temperature of the ZnO varistor adjacent to the spacer is lower in Figure 10. In Figure 11, the temperature of the three-column spacer gradually reduces to room temperature. The maximum error of  
Figure 11: Temperature comparison diagrams of the simulation and experiment between each column spacer. (**a**) is the temperature rise process of the spacers. (**b**) is the temperature drop process of the spacers. the spacer in column 1 is 2.54% at 14 min. The maximum error of the column 2 spacer is 4.74% at 14 min. The maximum error of the spacer in column 3 is 4.45% at 14 min.