On-site Dielectric Tests for Synchronise Condensers

Synchronous condensers (syncons) are an effective solution for improving the strength and stability of modern electricity grids where renewable energy sources are integrated on a large scale. Before energising a syncon, it is essential to carry out dielectric tests to verify its insulation integrity as the shipping and assembling process can introduce mechanical or environmental stresses that affect insulation performance. IEC 60034-1 and IEC 60034-27 recommend on-site tests such as power frequency withstand voltage, insulation resistance, polarization index, dielectric dissipation factor (DDF) measurement, and partial discharge (PD) testing to detect damage or contamination during installation. However, dielectric tests present specific challenges when conducted on-site. This paper describes practical methods for conducting on-site dielectric tests on syncons, with a focus on three key tests: the power frequency voltage withstand test, the DDF test, and the PD test. It presents the details of the tests and is aiming to support engineers and utilities in improving the reliability and effectiveness of field testing on syncons.