Study of associated root cause of mal- tripping and the environmental effect in arc flash protection system air insulated switchgear

• Main Author: Mohd Nur Khaidir Hussein
• Format: text::Thesis
• Language: English
• Published: 2023
• Subjects: STUDY OF ASSOCIATED ROOT CAUSE OF MAL- TRIPPING AND THE ENVIRONMENTAL EFFECT IN ARC FLASH PROTECTION SYSTEM AIR INSULATED SWITCHGEAR

This thesis presents the establishment of associated root cause of mal-tripping in arc flash protection system. This study related to the arc flash protection system that has been used in Tenaga Nasional Berhad (TNB) and has been proven a fast acting fault isolation system within air insulated switchgear in substations. However, there have been cases where mal- tripping occurred whereby the incomer was tripped even though the arc fault only affected one outgoing feeder. This caused a larger area than necessary to be affected by the arc fault causing huge load and revenue loss. There are also concerns on the long-term effects of environmental factors, in particular dust accumulation on the optical sensors, on the reliability and sensitivity of these sensors. The hypothesis on the root causes of mal- tripping was developed through the preliminary works and site investigation. The root cause was verified through modelling, simulation and laboratory experiment. Based on the study, the most probable root cause is the light leakage from the affected compartment to another compartment through gap or hole that exist between the compartment. It is recommended to close the gap by using a suitable silicone and industrial tape to prevent light leakage and hence preventing mal-tripping in arc flash protection system. This mitigation measures had been tested at laboratory condition and implemented in actual substation.