Evaluate future harmonic levels in central telephone exchanges. II

The increasing share of converter loads in electric power supplies has lead to a growing concern for harmonic distortion. In 1994, the Alexandria Electricity Company (Egypt) began a research program on harmonic levels at utility and customer buses. To ensure power quality for its customers, AEC sought to characterize the harmonic distortion for each type of activities. The central telephone exchange is one of them. A series of measurements were carried out at 12 central telephone exchanges to evaluate the influence of parameters such as harmonic impedances, currents and voltages.