Studies to investigate burnt neutral terminal of three-phase kWh meters and inrush current of household appliances

• Main Author: Fu, Suan Yi.
• Other Authors: Gooi Hoay Beng
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Electric power::Production, transmission and distribution; DRNTU::Engineering::Electrical and electronic engineering::Electric apparatus and materials
• Online Access: http://hdl.handle.net/10356/53232
• Institution: Nanyang Technological University

This project collaborates with Singapore Power (SP) PowerGrid Ltd., Metering department, to investigate on the burnt neutral terminal at the 3-phase kWh meter of customer premise and the reasons of electrical appliances being damaged after turning on its electricity supply and after the periodic replacement of the meter. Experiments were done to replicate these scenarios. Since the probability of such occurrence was 4 out of 10,000, this would indicate that the cause maybe a combination of the reasons below over a long period of time. It was researched that damaged electrical appliances could be due to the high inrush currents and/or the deterioration of the electrical components; while the burnt neutral terminal is usually associated with loose connection and/or high neutral current, which could be contributed by third harmonic, unbalanced loading and high power demand. Mitigations would include the use of capacitor banks, cables with higher rating, adopt paired neutral connection, installing temperature sensing circuit breakers, and regular checks and maintenances.