Seba KMT OWTS M28 Partial discharge Test and Fault Location System in Cable Insulation

Description

OWTS M28 Pro

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 d - 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 d-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.