Electrical Life Assessment of the Low-Voltage Circuit Breaker (LVCB) Considering Arc Voltage

Abstract

The low-voltage circuit breaker (LVCB) is commonly utilized in the distribution network. An accurate evaluation of its electrical life is related to the safety and reliability of electric energy output. The traditional arc erosion model only considers the effect of current on contact wear while ignoring the impact of operation conditions (supply voltage and power factor) on electrical life. As a result of the arc voltage, the original circuit topology changes, resulting in an early current zero. At 220–660 V AC supply voltages, arc voltage causes the distortion of the breaking current waveform, and the contact erosion amount (CEA) is smaller than that in the ideal case. This work investigates the effect of arc voltage on breaking current, develops an arc erosion model that includes arc voltage, and compares the CEA curves for various supply voltages and power factors. The electrical life of the LVCB is then simulated using the Monte Carlo approach to determine the distribution of electrical life under various operating situations. The results reveal that the LVCB’s electrical life diminishes as the supply voltage increases under the same power factor; it first declines and then increases as the power factor grows under the same supply voltage. For the combination of two parameters (220 V, 0.95) and (660 V, 0.65), the electrical life difference of the LVCB can reach 21.4%. The method solves the low accuracy problem of the LVCB life assessment under different operation conditions. It improves the efficiency of overhaul and maintenance on the LVCB in power distribution systems.