Gas-Guard 8 Online dissolved gas analysis sensor

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Dissolved gas analysis (DGA)Throughout your system there are transformers that are vital to the reliability of your grid – generator step-up transformers, large transmission transformers and critical substation transformers. Based on historical installation rates, the average transformer age is 40 years. However, age itself is not a cause of failure. As transformers age, they endure various stresses that can contribute to a variety of failure mechanisms. Appropriate online DGA monitoring and diagnostic tools can help utilities lower maintenance costs, extend transformer useful life and avoid unplanned failures. Gas chromatography (GC) has long been the accepted standard for the measurement of dissolved gas levels in transformer oil. GAS-Guard® 8 brings the DGA laboratory to your transformer with its rugged, closed-loop gas chromatograph.

Dissolved gas analysis is the single-most comprehensive tool for transformer condition assessment

Key benefits include• Field-based, fully automated DGA requires

no manual oil sampling or remote lab testing

• Use of the only measurement method specified for all DGA standards worldwide (IEE, IEC, ASTM)• Performs accurate DGA analysis on mineral and ester-based insulating fluids• Built-in self calibration system traceable

to the National Institute of Standards and Technology (NIST) executes weekly tests for performance confirmation

• Accurate and timely DGA results improve the ability to protect transformer against fault damage• Time-date stamped test results allow

correlation between real events and measured conditions

• Data generated by Gas-Guard 8 can be used to support condition-based maintenance programs

The software package included with the GAS-Guard 8 sensor allows the user to graphically display continuous gas evolution for each of the eight critical fault gases and as well as moisture, load and ambient temperature.

Online diagnostic toolsThe software package also allows the user to trace changes in fault severity over time through dynamic plots created using the Duval Triangle and Rogers Ratios analysis tools.

Online DGA data populating diagnostic tools deliver new insights. This displays Rogers Ratios (IEEE PC57.104.D11d) and basic gas ratios (IEC 60599-1999-03).

The Duval Triangle (IEC 60599-199-03) provides a diagnostic outcome for combinations of three fault gases.

Comprehensive data requires powerful analytical tools

Moisture-in-oil and oil temperature option

Parameter Accuracy1 Range

Moisture-in-oil ±2% 0 – 100% RS2

<10% of reading for oil temperature >30° C

0 to 803 ppm

<18% of reading for oil temperature <30° C

0 to 803 ppm

Oil temperature ±0.1° C (typ.) -40° C to +180° C1 Includes nonlinearity and repeatability2 Relative saturation3 Upper range limited to saturation

Environmental specifications

Operating temperature –50° C to + 55° C

Cold-start temperature –20° C

Operating humidity 5% to 95%, RH noncondensing

Oil inlet pressure 0 to 45 psi, to 3 bar

Storage temperature –40° C to +75° C

Storage humidity 5% to 95%, RH noncondensing

Physical specifications and weights

Height 22.0 in (55.9 cm)

Width 20.0 in (50.8 cm)

Depth 11.2 in (28.4 cm)

Weight 65 lb (29.5 kg)

Enclosure rating IP 66, NEMA 4

Packaged dimensions 26.4 in x 26.4 in x 15.9 in (67 cm x 67 cm x 40.3 cm)

Shipping weight (monitor only) 70 lb (31.8 kg)

Certifications/standards

Electromagnetic compatibility

Specification Test method

EN 61326 Class A: 2002 EN 61326: 2002 radiated emissions,

2002 conducted

emissions

EN 61000-3-2: 2000 EN 61000-3-2: 2000 current harmonics

EN 61000-3-3: 2001 EN 61000-3-3: 2001 voltage

fluctuations

EN 61326 Annex A: 2002 IEC 61000-4-2: 2001 ESD

IEC 61000-4-3: 2002 radiated immunity

against HF field

IEC 61000-4-4: 2004 EFT

IEC 61000-4-5: 2001 surge

IEC 61000-4-6: 2004 conducted RF

immunity

IEC 61000-4-8: 2001 magnetic field

immunity

IEC 61000-4-11: 2004 voltage dips and

interrupts

Safety

IEC 61010-1, IEC 61010-2-81

UL 61010-1 (2nd Edition), UL 60950-1 Clause 6.4

CSA-C22.2 No. 61010-1-04

Input power requirements

Voltage 115 VAC or 230 VAC ±15%

Frequency 50/60 Hz

Current 6 A maximum at 115 V

3 A maximum at 230 V

Total dissolved gases

True total dissolved combustible gas (TDCG) output is available(∑H2, CO, CH4, C2H2, C2H4, C2H6 in PPM)

Each gas is measured at 100% of detected level

Total hydrocarbons (THC) output is available (∑CH4, C2H2, C2H4, C2H6 in PPM)

Each gas is measured at 100% of detected level

Gas analysis

Oil sampling is continuous and gas analysis intervals are user-selectable from 2 hours to 12 hours (Default: 4 hours)

All data is time-date stamped

Up to two years of data stored in memory

Automatic schedule acceleration when rate of change alarm limit exceeded

(Default: 1 hour)

System performs periodic autocalibration to NIST traceable gas standard

Alarms

For each individual gas measured:

Two individually programmable caution and alarm settings for level (ppm) as

well as rate of change (ppm/day)

Freely programmable relay contact for gas alarm or service event

One relay contact for self-monitoring of power supply

External sensors

Current sensor for load-dependent gas development

Ambient temperature

Moisture in oil and oil temperature

GAS-Guard 8: Facts and figures

Communications options

Standard physical layer interfaces include RS-232, RS-485, Ethernet

(10/100Base-TX), V.92 internal POTS modem

Optional physical layer interfaces include cellular modem, Ethernet

(100Base-FX), wireless radio

Three 4-20 mA inputs and one RS-232 port available to connect to

optional devices

Protocols supported: TCP/IP, DNP3, Modbus RTU and ASCII, OPC

The Siemens GAS-Guard 8 sensor provides a complete online dissolved gas analysis. Through chromatography, GAS-Guard 8 generates individual mea-surements of eight critical fault gases found in transformer oil. Accu-racy is commensurate with traditional lab results. The sensor continu-ally collects oil samples as often as every two hours. GAS-Guard 8 can also measure moisture in the oil, oil temperature and ambient tem-perature. DGA results and other measurement data are time-date stamped and can be correlated to transformer load.

Gas Accuracy1 Repeatability2 Range3

Hydrogen H2 +/- 5% or +/- 2 ppm <2% 2-3,000 ppm

Oxygen O2 +/- 5% or +30 / - 0 ppm <1% 30-5,000 ppm

Methane CH4 +/- 5% or +/- 10 ppm <1% 10-5,000 ppm

Carbon Monoxide CO +/- 5% or +/- 3 ppm <1% 3-10,000 ppm

Carbon Dioxide CO2 +/- 5% or +/- 5 ppm <1% 5-30,000 ppm

Ethylene C2H4 +/- 5% or +/- 3 ppm <1% 3-5,000 ppm

Ethane C2H6 +/- 5% or +/- 5 ppm <1% 5-5,000 ppm

Acetylene C2H2 +/- 5% or +/- 1 ppm <2% 1-3,000 ppm

NOTES: All specifications are independent of oil temperature and gas pressure level.1 Percent of ppm - whichever is greater2 At gas calibration level3 Gas-in-oil

DGA tolerances of the GAS-Guard 8

Graphical representation of GAS-Guard 8 connected to the transformer tank.

DGA tolerance of GAS-Guard 8

Siemens Industry, Inc.7000 Siemens Road Wendell, NC 27591

For more information, please contact our Customer Support Center. Phone: 1-800-347-6659

usa.siemens.com

Order No: IC1000-E240-A145-X-4AUSPrinted in USA©2016 Siemens Industry, Inc.

Subject to changes and errors. The information given in this document only contains general descriptions and/or performance features which may not always specifically reflect those described, or which may undergo modification in the course of further development of the products. The requested performance features are binding only when they are expressly agreed upon in the concluded contract.