Lightning strike is one of the leading causes of transmission line trip-outs worldwide. In China, for instance, lightning accounts for over 50% of power system failures, and operational data from five provinces within the China Southern Power Grid over a five-year period indicated that approximately 62% of all trip-out faults were lightning-related. Externally Gapped Line Arresters (EGLAs) have emerged as highly effective countermeasures for transmission line lightning protection.
Line arresters are critical for overvoltage protection in transmission and distribution networks. However, their external insulation performance can be severely compromised under harsh environmental conditions. While pollution and moisture have long been recognized as flashover contributors, the synergistic effect involving impulse current—simulating a lightning strike—remains underexplored. This article presents the physical mechanisms by which (pollution), (moisture), and impulse current collectively trigger external insulation flashover in line arresters, providing insights for improved insulation design and maintenance strategies.
Metal oxide surge arresters (MOSAs) are critical components in power transmission and distribution networks, protecting equipment against overvoltages caused by lightning strikes and switching surges
Lightning strikes remain the primary cause of unplanned outages on overhead transmission lines, directly impacting grid reliability and operational costs. While line lightning arresters (LLAs) are effective protection devices, their indiscriminate installation leads to diminishing economic returns. This article presents a quantitative methodology to determine the optimal density and placement of LLAs by analyzing localized lightning trip-out rates, tower grounding characteristics, and insulator flashover thresholds. A risk-priority model is proposed to minimize total line trip-out probability under a fixed budget constraint.
Metal oxide surge arresters (MOAs) have become the primary overvoltage protection devices in modern power systems due to their excellent nonlinear volt-ampere characteristics, high energy absorption capacity, and gapless design. The zinc oxide (ZnO) varistor, as the core component of MOA, determines the overall performance and reliability of the arrester. However, under real-world operating conditions—particularly in high-temperature and high-humidity (HTHH) environments prevalent in tropical coastal regions and subtropical industrial zones—the aging process of ZnO varistors is significantly accelerated, posing serious threats to the safe and stable operation of transmission lines
Coastal environments pose severe challenges to transmission line insulators due to high humidity, salt spray, and persistent contamination. This study compares the flashover performance of three common insulator types – porcelain, glass, and composite (silicone rubber) – under simulated coastal pollution conditions. Results indicate that composite insulators exhibit superior flashover voltage retention and hydrophobic behavior, while porcelain and glass require longer creepage distances to achieve equivalent reliability. The findings provide practical guidance for insulator selection in coastal transmission projects.
