Atec HDW-OWTS-M28 User Manual

SebaKMT · Dr.-Herbert-Iann-Str. 6 · 96148 Baunach/Germany · Tel. [phone] - 6 80
Fax [phone] - 22 73 · [e-mail] · www.sebakmt.com

ISO 9001:2000

Technical data subject to change without notice.
LFT_OWTS M 28_eng_2007_05

sebaKM T is a regi stered t radem ark of the s ebaK MT group

OWTS M 28

Partial discharge Test and Fault
Location System

Benefi ts

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

Description

The oscillating wave test system OWTS is used to identify,
evaluate and locate partial discharge (PD) faults in a 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 offi ce. The PD fault location is
based on the time domain refl ection 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 fi xed 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 cause no long-term infl uences.

The PD extinction voltage and the tan δ-value can be easily
determined due to the decaying amplitude of the test voltage.
Critical PD levels responsible for the future status of the cable
insulation are an 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.

Features

PD diagnosis by means of damped AC voltage (DAC)
PD level measurement according to IEC 60270
Automatic adjustment of the bandwidth of the

measurement circuit for optimised signal detection

Automatic calibration mode with joint location feature
PC with WIN XP and WLAN for system control
Statistical PD fault acquisition, online processing
Menu-driven unit to operate the test sequence
Portable design, low weight, easy set-up on-site

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 PD-

localisation

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