**3. Procedure**

Measurements were carried out in a semi-anechoic chamber located at a latitude of 2250 m and pressure of 585 mmHg (Mexico City). The temperature inside the chamber was 25°C with a relative humidity of 50%. To start the measurements, the electromagnetic environment was first analyzed in the range of measurement frequencies under test in order to ensure that there would not be a presence of spurious signals.

CD onset corona voltage is well identified for the different configurations of needle plane, corona cage, and others [17, 18]. A good reference for the presence of the phenomenon is the corona current pulse, which is detected in the conducted form [18]. The detection of such as current may be carried out between the power supply and configuration under test or in return plane. In the first case, a coupling circuit is needed, which is a complex method of measurement. The measurement of corona current at the return plane is simpler because measurements with a current probe are enough as a CT.

The rise time of the corona current pulse gives information of the phenomenon, and the fall time is a function of the parasitic electrical components of the configuration. Therefore, to have a better shaped pulse, it is necessary to optimize the circuit of the discharge configuration. Knowing the rise time of the corona pulse, the fundamental frequency can be determined, both for conducted and radiated radio electric emissions [19].

To carry out the electromagnetic spectrum analysis of the corona discharge, we did the following:


carried out in the near field. The results are presented in dBμV; from these, the current can be calculated to predict the far field.

