Ripple control interference at irrigation installations

Series resonance at ripple carrier frequencies, between distribution transformers and power-factor correction capacitors, has occurred at irrigation installations in the North Canterbury Electric Power Board´s rural supply area. Inductor blocking to relocate the series resonance at a lower frequency is discussed. A low-cost inductor suitable for practical use is suggested. The use of interactive linear-network-simulation computer programs to analyse the inductor blocking requirements of various motor, transformer and capacitor combinations is then outlined, and optimised inductor parameters for the various equipment combinations used at pumps sites are presented. Laboratory tests with the low-cost inductors confirm the theoretical analysis