Voltage and current harmonics caused by corona

THE FOLLOWING investigation was made to study the effects of corona in producing voltage and current harmonics in transmission systems. In the early work on corona in 1910 a very complete oscillographic study was made of voltage and current. It was found that the current wave of corona loss very much resembled the excitation current wave of a transformer or iron-core reactor. A typical corona wave is shown in Fig. 1.
¹
This wave has a very prominent third harmonic.