GR-10
Oscillating Wave Test System
GR-10
GR-10
Dielectric Diagnosis and Partial Discharge Measuting System
• PD Measurement by means of DAC similar to nominal net frequency
• Online processing for complex PD-Diagnosis
• Portable test system, compact design and low weight
Integrated tan δ – measurement
The oscillating wave test system OWTS is used to identify, evaluate and locate partial discharge (PD) faults in a cable insulation and in joints and terminations.
The HV unit generates the attenuated oscillating frequency up to the peak voltage of the system. An Embedded controller for the operation and the digital signal processing and storage from two 100 MHz AD converter systems is intergrated in the cylindrical housing. Transport wheels permit easy transportation. The communication to the user interface of the notebook is done by W-LAN. Optional a optical data link is possible.
The OWTS can also be coupled with a VLF System. In this case the VLF provides, controlled by the OWTS, the High Voltage supply.
Key Benefits:
• PD diagnosis under oscillating wave test voltage – electrical field distribution as in nominal service conditions
• PD evaluation possibility and pattern recognition at the nominal voltage level
• Automatic calibration and joint location facility
• PD level measurement according to IEC 270 at a bandwidth of 150 … 650 kHz
• Semi- and fully automatic PD analysing software for defect location with mapping feature
• Calculation of the cable capacitance and the tan delta value of the test object from the characteristic decrease of the voltage wave shape
• Simple to use and easy to handle menu-driven unit for operation of the test sequence
• Compact design; low weight
• Compact PD: combination of OWTS, vlf test unit and the fault location system Compact
Description
The oscillating wave test system OWTS is used to identify,evaluate, and locate partial discharge (PD) faults in cable insulation and accessories in all types of medium voltage cables. The system consists of a notebook as a WLAN control unit and a HV unit. The HV unit contains a HV source and a resonance inductor with an integrated electronic switch to generate the AC test voltage. The HV divider and an embedded controller for the digital data acquisition and PD signal processing is integrated. The storage, analysis and evaluation of the PD signals takes place in the notebook and can be done either on site or in the office. The PD fault location is based on the time domain reflection method. For the PD diagnosis the test object is charged to the preselected peak value by a HV source within a couple of seconds and afterwards shorted with an electronic switch via a resonance coil. Thus a sinusoidal oscillating AC voltage with low damping is created (DAC). The frequency is fixed in a range from 50 Hz to several 100 Hz, depending on the capacitance of the test object. Since the frequency of the test voltage is close to nominal service conditions, all measured PD activities can be effectively evaluated. The oscillating voltage energizes the test object only for a few 100 ms and therefore causes no long-term influences. Due to the decaying amplitude of the test voltage, the PD extinction voltage and the tan δ-value can be easily determined. Critical PD levels responsible for the future status of the cable insulation are important criteria in the evaluation. The analysis and evaluation of the typical PD parameter as well as the PD fault location supports the Asset Management for reliable decision criteria for maintenance or replacement activities.
Scope of delivery
HV unit
Notebook with WLAN connection to the HV unit
Safety-Box with HV ON/OFF; Emergency push button and key switch
Accessory bag
Operating manual
5 m HV test lead; power supply- and grounding cable
OWTS Explorer package, 2 Dongle CD-ROM
Calibrator
Technical Data
Max. DAC outputvoltage 28 kVpeak / 20 kVrms
DAC frequency range 50 Hz … 800 Hz
Capacitance range 0,025 µF … 2 µF
HV charging current 10 mA
PD measuring range 1 pC … 100 nC
PD level detection acc. to IEC 60270
Bandwidth for PDlocalisation 150 kHz … 45 MHz
Dissipation factor tan δ 0,1 % … 10 %
Power supply 110 … 240 V-AC, 50 … 60 Hz
Operating temperature -10 °C … +40 °C
Weight app. 55 kg
Components
Unit 1 Ø: 600 mm, H: 650 mm
Unit 2 Notebook app. 2 kg