Key technologies for ultra-wideband PDs detection in transformer under AC/DC withstand voltage tests, part 2: Overview of on-site PD test of converter transformer

In this paper, the author introduces the on-site PD test methods and requirements of converter transformers in detail. On-site PD tests of converter transformers are divided into two types: AC test and DC test. The PD test under DC voltage is only carried out on the valve side, while the PD test under AC voltage needs to be carried out on the grid side and the valve side. According to the different connection methods of the grid side and valve side, different voltage application methods are adopted. For the Y/D connected converter transformer, the voltage is applied symmetrically on the valve side, and for the Y/Y connected converter transformer, the unilateral pressure is applied on the valve side. In addition, an on-site partial discharge test of a converter transformer is used as an example to explain the calculation process of the test parameters and prove the rationality of the applied voltage method and the calculation of the test parameters.