Brochure · EN — Siemens Energy Transmission Service brochure (2021) for Assetguard GDM, an SF₆ gas density monitoring system for gas-insulated equipment. It continuously acquires data from Modbus RTU gas density sensors / hybrid density monitors — scalable up to 512 sensors (32 per RS485 daisy-chain network) behind a single Assetguard Gateway web HMI — and turns it into leakage early warning: Warning / Stage 1 (Low-Pressure) / Stage 2 (Block-out) alarms, a Time-to-next-Alarm prediction over the next 90 days, gas loss reporting in kg, and an overall SF₆ gas inventory, with SCADA integration via IEC 61850, IEC 60870-5-104, DNP3, Rest API and voltage-free contacts.
The recent European and North American legislation has focused on greenhouse gases such as SF₆, with the target of reducing emissions to 0,5% per annum. As a result, gas density monitoring is essential to improve leakage visibility, notwithstanding the superior performance of modern Gas Insulated Switchgear (GIS).
The Siemens Energy Assetguard GDM takes care of the actual SF₆ gas condition and helps manage a more dynamic and extensive network where conventional routine inspections are not viable, such as offshore installations.
With its state-of-the-art web-based user interface, the system provides a Single Line Diagram view (SLD) for easy localization, gas density measurement with high accuracy, recognition of trends and prediction of intervention dates, an overall SF₆ gas inventory, and data storage for expert analysis.
Alarms can be forwarded to the Siemens Energy Customer Support Center, with easy navigation to investigate the actual condition or an alarm status. Different users can access the system simultaneously — even on mobile devices — without disturbing other systems for control, protection, and automation. Graphical web elements can be reused in other applications, and the interface offers multi-language support and user-based permissions.
Early warning in case of SF₆ gas leakage (Time to next Alarm) and a Gas Lost Report for asset managers. The system facilitates integrability (e.g., in SCADA systems or asset management platforms), enables easy involvement of Siemens Energy Customer Support, and integrates the monitoring gas zones in one single HMI.
The Assetguard GDM application has been adapted to monitor gas density sensors / hybrid density monitors with a Modbus RTU interface. Thus, a single Assetguard GDM system can be configured to monitor up to 512 Modbus sensors, seamlessly integrated in a single user interface, i.e., the Assetguard Gateway.
Depending on the project-specific requirements the system can be delivered with: [Optional] Modbus gas density sensors / hybrid density monitors; wiring for the connection of the Modbus sensors in a RS485 network (daisy chain); a Modbus gateway for the communication with the sensors; the Assetguard Gateway + GDM Knowledge Module running in an industrial PC; a web-based user interface; a central cubicle containing the industrial PC and further needed communication and power supply components; NTP time synchronization; communication protocols and free voltage contacts; an uninterrupted power supply (UPS); and [Optional] integration with other monitoring systems (partial discharge, circuit breaker).
Data acquisition, self-test and alarming characteristics as printed in the brochure:
| Characteristic | Specification |
|---|---|
| Acquisition | Modbus RTU |
| Self-Test | broken cable detection, Sensor failure |
| Gas Density Alarms | Warning, Stage 1 (Low-Pressure), Stage 2 (Block-out), Time to next Alarm (next 90 days), Overpressure |
System-level properties of the delivered components:
| Property | Specification |
|---|---|
| Input Channels | Scalable up to 512 Sensors (32 Sensors per RS485 Network) |
| Enclosure Dimensions | 600x625x600 mm (other dimensions under request) |
| Environmental Conditions | Operating Temperature: -25°C to 55°C; Humidity: =93%RH non-condensing |
| EMC Standards | Immunity for usage in power station or substation environment, IEC 61000-6-5 |
In the standard system architecture, gas density sensors and hybrid gas density monitors (32 per RS485 daisy-chain network) connect through a Modbus gateway (serial device server, connection up to 512 Modbus slaves, i.e. sensors) to the Assetguard Gateway + GDM Knowledge Module in a cubicle, fed by a 24 VDC power supply (120-230 VAC / 110-220 VDC input). The customer network connects over copper / fiber optic with DNP3, IEC 61850, web HMI, 8x free voltage contacts and IEC 60870-5-104 (the diagram notes that additional components are required and the system architecture may vary). The gateway's headline features as printed:
| Feature | Specification |
|---|---|
| Communication Protocol | IEC 61850, IEC 60870-5-104, DNP3, Rest API, Voltage-Free Contacts |
| Historical Data Storage | Min. 5 years |
| Gas Density Analysis | Time to next Alarm (Predictions), Gas Loss report (kg) |
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