DC distribution networks are gaining widespread adoption due to their high efficiency, flexible control capabilities, and seamless integration with renewable energy sources, energy storage systems, and DC loads.
Current-limiting fuses are critical protection devices in modern power systems, capable of interrupting fault currents within milliseconds. This article reviews the arc characteristics during high-current interruption and the post-arc dielectric recovery mechanisms that determine successful current interruption. Key aspects include the physical processes of arc ignition and suppression, the role of quartz sand filling in arc cooling and plasma confinement, the nonlinear evolution of arc resistance, and the dielectric recovery dynamics after current zero. Understanding these mechanisms is essential for optimizing fuse design and enhancing interruption reliability.
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.
