Question

What is the best approach to isolate a small load sensitive to harmonics from a very large load, which produces high harmonic currents?

A. Provide a separate return for each phase of the high harmonic generating load and increase the size of this load’s phase supplies

B. Increase the size of the neutral conductors to minimise the effect of the harmonics

C. Use a ferro-resonant transformer for the sensitive load

D. Shorten the distance between the service panel and the loads to reduce the voltage produced by the harmonic currents

Answer 1

B. Increase the size of the neutral conductors to minimise the effects of the harmonics.

Oversized neutral conductor is one of the best approach to solve the problem of harmonic distortion. Electronic equipment carries with it significant potential for generating third-order harmonics—primary culprits in neutral overloads. Harmonics are not new problems for electrical-distribution systems. Branch circuits feeding high-intensity discharge always have required full-sized neutrals, along with dedicated neutrals for each dimmer branch circuit.