Effect of utility system X/R ratio on harmonic amplification characteristics of a plastic plant

This paper investigates the harmonic amplification characteristics of a plastic plant considering the changing of X/R ratios in the utility system. In the design stage, in general, the utility X/R ratios are assumed unchanged and the impedances are also frequency-independent. It makes the computation results more conservative. However, in a weak power system, such as the Taiwan Power Network, the X/R ratios depend on the changing transmission system configuration and the system short-circuit capacity. Field measurements and computer simulations indicate that the X/R ratios have a great impact on harmonic amplification and power loss of harmonic filters. Hence, one should consider the effect of changing X/R ratios on harmonic amplification in design stage in order to improve the reliability of filters.