RMS digital trips offer increased accuracy and reliability advances in low-voltage circuit breaker trip technology

With the growing use of static power converters and the subsequent increase in the harmonic content of power system current, low-voltage solid-state current-sensitive trip sensing techniques are becoming increasingly important. The function of low-voltage circuit breaker trip units and the need for direct root mean square (RMS) overcurrent sensing of the sinusoidal and nonsinusoidal current wave, including the percent error analysis, is reviewed