DC test systems of the type DCG provide a DC output voltage with a continuous DC current as specified. The benefits of this type of DC generators are the small footprint required, their compact and modular design and low weight. Although designed for laboratory use, they can also be used on-site under fair weather conditions.
Furthermore, with the use of a blocking impedance super-imposed transient voltages can be applied to the test object simultaneously with the DC voltage.
The setup of the system consists of a power cubicle containing the switches to provide grid power to the system (usually 3 x 400V <100kW), also including components of the control system and the frequency converter with filter. The frequency converter operates at a frequency of approx. 1000Hz and provides together with the filter an almost sinusoidal output voltage. This voltage is provided to the primary of a high voltage transformer feeding into the cascaded setup of the capacitor and rectifier columns.
- Small footprint required
- Compact & modular design
- Low weight
- Super-imposed transient voltages can be applied to the test object simultaneously with the DC voltage using a blocking impedance
The rectifier valves contain the power electronic elements with remote controlled polarity reversal. They are of reliable design with proper voltage grading and internal protection elements. The polarity reversal is activated by the control system via a glass fiber. The different units are hermetically closed and oil insulated. The thermal power generated, is dissipated by natural cooling to assure continuous operation. The cascade as well as the transformer have additional transient protection elements for transient over voltages. At the output of the cascade a resistive and capacitively graded high voltage divider is situated. The output voltage is measured here. Furthermore, this divider can also be used as a DC coupling capacitor for PD measurement, if required. At the output a blocking impedance can be installed to enable testing with super-imposed BIL and SIL pulses simultaneously with the DC voltage applied to the test object.
The whole system is operated and controlled by a control system providing all system functions such as HV ON and OFF, increasing and decreasing the output voltage, as well as polarity reversal. Furthermore, all measurement values are displayed, monitored and recorded there. Programmable functions as well as timer and automatic operation modes are available. The control system complies with the latest safety standard such as EN60204-1 and EN ISO 13849-1:2006 / IEC 62061:2005. The whole system fulfills the testing standards IEC 60060-1 and IEC 60060-2.