To maximise both user convenience and value for money, Megger’s new HV DAC300 test set combines withstand testing facilities and partial discharge diagnostics for HV cables operating at up to 230 kV in a single readily transportable system.
The DAC300 uses damped AC (DAC) voltage technology to energise the cable and is capable of generating peak voltages of up to 300 kV. It can be used with cable with capacities of up to 8 µF.
This versatile new test system is suitable for identifying, evaluating and locating partial discharge (PD) faults in cable insulation and cable accessories in all types of high-voltage power cables. Typical applications include acceptance testing of new and repaired cables in accordance with the IEC 60840 and IEC 62067 standard, and condition analysis of service-aged cables.
An important benefit of the system is that the frequency of the DAC test voltage generated is close to nominal power frequency. This means that the measured PD values relate directly to the in-service characteristics of the cable. In particular, the PD inception voltage (PDIV) and PD extinction voltage (PDEV) can be readily and accurately determined.
Key features include adjustable detection sensitivity, automatic calibration mode with joint location facilities, real time data processing so that results can be examined while the test is being performed, an intuitive menu-drive user interface, and an internal cable database with search, browse and edit functions.
The results provided by the DAC300 test system give crucial information about the status of the cable insulation, and are an invaluable aid to asset management, as they provide reliable criteria for making informed decisions about cable maintenance and replacement.
The system includes a laptop computer running the specially developed software that is used to control the unit. The software also handles data storage, analysis and evaluation and can configured to provide results in real time, or to carry out evaluation after the tests have been completed.
To ensure ease of transportation, the DAC300 test set is supplied as four separate units: the HV source, which only requires a 400 V supply with a capacity of 5 kVA; the HV switch; the HV resonance inductor, divided into four components for ease of set-up; and the HV divider/PD analyser. The units are housed in transportation cases, and two further cases are supplied which conveniently house cables and other accessories.