Determination of penetration levels of static power converters connected to a distribution system based on harmonic limits using a probabilistic approach

This paper proposes a novel probabilistic approach to evaluate allowable penetration levels of AC-to-DC static power converters uniformly distributed along the feeder of a radial distribution system. The allowable penetration levels of the studied system are based on the calculated results of both voltage distortion limit and current harmonic limit. Harmonic currents produced by static power converters have randomly varying firing angles with fixed upper and lower limits. A probabilistic model is established for the injected harmonic currents using expected value and variance. Allowable penetration levels of connected static power converters are practically determined by feeder's current capacity, line impedances, number of connected static converters along the feeder, specific injected harmonic currents, total harmonic distortion (THD) limit based on IEEE Standard 519-1992, and voltage variation limitation at the point of common coupling (PCC). It can be concluded from the simulation results that the proposed probabilistic approach is very effective to evaluate the penetration levels of a number of static converters connected to a radial distribution feeder.