973-SF6 Analyzer – DEW POINT HYGROMETER WITH A CHILLED MIRROR 

  • Simultaneous measurement of humidity, SF6 purity and SO2 concentration6
  • Integrated gas recovery system with automatic pump-back
  • Fully automated SF6 gas testing
  • Fundamental drift-free measuring principle
  • Measurement results at SF6 compartment or standard pressure
  • Intuitive color touch screen user interface

Optimum SF6 Gas Analysis Solution

The 973-SF6 is an advanced analyzer for the measurement of humidity, SF6 purity and SO2 concentration in SF6 gas insulated switchgear (GIS) and other high voltage equipment. With its internal gas containment and recovery system, the 973-SF6 provides a high quality and environmentally safe measurement solution within a single, self-contained unit.
Pure SF6 is the standard filling within GIS, but over time gas compartments become contaminated with water vapor (H2O) through permeation and by desorption from internal components. Whilst water vapor and SF6 do not normally react with each other,
in the presence of a high-energy discharge, hydrogen and oxygen disassociated from water vapor will react with the sulfur and fluorine from SF6 to form breakdown components. These include Sulfur dioxide (SO2), Hydrofluoric acid (HF) and Sulfuric acid (H2SO4) that are corrosive to the internal components of gas compartments. SF6 with low water vapor content (low humidity) significantly reduces the potential for formation of these corrosive compounds, which is why accurate and repeatable measurement data is an invaluable part of any GIS preventative maintenance program.

Accuracy and Repeatability using Advanced Chilled Mirror Technology

A polished mirror surface is cooled to the point at which condensation forms on the mirror surface, then the temperature is measured. Since this condensation temperature is specific to water vapor concentration, highly precise results are achieved without t he need for humidity sensors.
Chilled mirror technology is the most accurate and reliable humidity measurement technique available. Since the 973-SF6 employs the same condensation principle in the determination of SF6 purity, the same high levels of repeatability and long-term stability are attained for both key SF6 measurements.

Intuitive User Interface

Measurement results are clearly presented on a clear full color touch screen in the units of choice. Results are held on the display for user notation and can easily be imported into Microsoft Excel using the software and cable supplied. The 973-SF6 data format is compatible with test procedures issued by all major SF6 equipment manufacturers and standards organizations such as CIGRE and IEC.

Technical data

PARAMETER VALUE
Measuring Range: Frost/Dew Point: -50…+20 °C
Humidity content by volume: 40…20000 ppmv
Volume SF6: 0…100%
Inlet pressure: 120…1000 kPa abs
Accuracy: Frost/Dew point: ≤ ± 0,5 °C
ppmv /ppmw: ≤ ± 1 ppm +6% of reading
Volume SF6: ≤ ± 0.5%
Pressure: ≤ ± 3 kPa
Repetitiveness: < +/- 0,1°C, +/- 1 digit
Digital output: RS-232
Analog output: 10 mV/°C, 0 °C = 0 mV, mA optional
Principle of measurement: Dew point hygrometer with a mirror, optical detection
Cooling: Thermoelectric, Peltier element, 3-step 
Power supply voltage: 110...240 VAC, 50/60 Hz
Energy consumption: About 200 W
Environment temperature: -10...+40°C for work
 -20…+50 °C for storage
Environment humidity:
 Maximum 98% RH, without condensation
Weight: Approximately 16,5 kg
Overall dimensions 420 (width) x 155 (height) x 390 (depth) mm

Options and accessories

SO2 Measurement

The 973-SF6 is available with integrated measurement of SO2 concentration (ppmv). The electrochemical SO2 measurement cell is conveniently located on the rear panel for simple user replacement with low cost, pre-calibrated, interchangeable SO2 modules. From 2012, all new 973-SF6 instruments are ready for SO2 measurement, so if required, this option may be field upgraded by means of a plug-in sensor module and a software activation key. Earlier instruments can be factory upgraded if required; please contact MBW or your local representative for guidance. All SO2 sensors supplied by MBW are calibrated before delivery.MBW Callibration Ltd. has a right to change devices and their parameters without a former notifications.

Transportable with Robust, Shock-Resistant Case

The 973-SF6 is supplied complete in a robust, shock-resistant, waterproof case with wheels for use on-site and for transportation. Sample lines and the most common DN8 and DN20 fittings are included. Alternative fittings are available to suit almost any SF6 installation.
Producer:
MBW Calibration Ltd.
Seminarstrasse 57
CH-5430 Wettingen
Switzerland
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