Harmonic Interaction Between HVDC Converters and ac Power Systems

A technique is presented for calculating the harmonic interactive behaviour between HVdc and ac systems. The ac system is represented by discrete impedances at harmonic frequencies, and the calculations involve the repeated iteration of a large computer program representative of the interaction of generated ac harmonic currents with the ac system impedances and filters. Examples of computed harmonic conditions are presented, and the degree to which the harmonic behavior is dependent on the ac system impedances and filters is discussed for both normal and abnormal harmonics.