DC voltage sources
The DC voltage sources include the following systems:
- 1.2 MV DC voltage source
- 600 kV Unipolar Greinacher Cascade
- 600 kV Bipolar single-stage Greinacher Cascade
1.2 MV DC voltage source
The DC voltage source consists of 3 encapsulated modules (built in 2018). It is a transformer supported Greinacher cascade, which can create both polarities. A voltage divider is integrated in the source. The tests are carried out in accordance with IEC 60060-1. Superimposed impulse voltage tests can also be carried out with the series resistor of the DC voltage source . These are tests with applied DC voltage and superimposed lightning / switching impulse voltage. This kind of tests are of particular interest for HVDC cables, DC-GIS or DC GIL applications. For high voltage connection, a resistively graded support insulator is also available.
600 kV Unipolar Greinacher Cascade
The DC voltage source (built in 1965) is built in a metal encapsulated enclosure with 4-stages and is powered by 7.3 kHz converters. The DC voltage is carried out through the enclosure with a high voltage cable and cable sealing end to air. The DC source generates an extremely low current ripple. Therefore, the source is excellent for sensitive insulation tests. The source thus excels by far the requirements of IEC 60060-1.
600 kV bipolar Greinacher Cascade
This Greinacher cascade can be operated in both polarities and is mobile (built in 1964). The polarity can be changed by turning the diodes.