Environmental meteorological parameters (temperature, humidity, air pressure, etc.) have an important impact on short gap streamer discharge. Based on the streamer theory and particle continuity equation of gas discharge, a short gap streamer discharge simulation model is established, and the influence of environmental parameters on the dynamic development process of streamer discharge is simulated and analyzed. The short gap air gap discharge characteristics were tested in a self-made gas discharge chamber. The results show that at low humidity (relative humidity 80%), with the increase of humidity, the electron density of the streamer channel decreases, the field strength of the streamer head decreases, the development speed of the streamer slows down, and the gap breakdown voltage increase. With a decrease of gas pressure, the electron density of the streamer channel decreases, the field strength of the streamer head decreases, the development speed of the streamer increases, and the gap breakdown voltage decreases; The temperature change has little effect on the streamer development process.

The arrangement of insulator strings has an effect on its pollution flashover characteristics. A new arrangement of insulator strings, inverted T‐type arrangement, is proposed in this study. The electric field distribution is simulated and the pollution flashover characteristics are tested in an artificial climate chamber. The test results indicate that the inverted T‐type arrangement can greatly improve the flashover voltage of polluted insulator strings, the ‘7 + 2’ inverted T‐type arrangement can increase the flashover voltage of each insulator by 8.5% on average, and the ‘3 + 3’ inverted T‐type arrangement can increase the flashover voltage of each insulator by 13.4%. The discharge process is different from that of the normal suspension string when the insulator string is inverted T‐shaped, i.e. a local arc is produced at the low voltage end of the insulator string and develops downward along the suspension part. While as for the horizontal tension string parts, it is difficult to generate arc during discharge development.