SF6 – the insulation gas with excellent electrical characteristics
A gas density gauge is assembled on every compartment of a SF6-insulated switchgear. This gauge measures pressure at 20°C reference for each gas compartment in a constant manner, with a hermetically sealed sensor. If a high-voltage product has SF6-insulation inside, the gas needs to be monitored for two essential reasons: the functionality and the environmental aspect.
Leak detection for reliable functionality and a healthy environment
Regarding the functionality aspect, gas is needed for two reasons: the insulation of conductors and electrical parts from their surrounding compartment and the arc quenching during switching operations. As SF6 is an insulation gas with excellent electrical characteristics, it is possible to distribute and transmit energy with highest electrical safety. If pressure rises inside a compartment, as a result of an internal fault or lightning, the monitor detects this fast-rising pressure and instantly communicated with the control and protection system to reestablish a fault-free operational condition. In the unlikely event of low pressure inside the gas compartment, caused by an internal or external leak, a switching operation could lead to destruction of the equipment. Both switching operations either at lower or higher pressure can cause equipment failure.
Gas monitoring can detect gas leaks in an early state, which – undetected - could lead to gas losses into the atmosphere over several years. As SF6 is not only an excellent insulation gas, it has also the highest known global warming potential, about 22,800 times that of CO2. Hence, gas losses have a high impact on the environment, which makes it necessary for OEMs to apply state-of-the-art sealing technologies, highest standards of material and guarantee most reliable testing methods. All is designed to avoid any gas loss of SF6 into the atmosphere.
Comprehensive gas monitoring with Sensgear®
Gas monitoring via Sensgear® is taking the concept a step further. Sensgear® portfolio for switching products includes e.g. online gas density monitoring and gas inventory reporting features, thereby giving the operators the means to reduce costs and to comply with regulations. It paves the way for the sustainable and digital substation of the future. Sensgear® gives the operator connective transmission products that use data to optimize grid operations and to make better-informed business decisions.
Applying artificial intelligence to optimize gas monitoring
Where conventional trending models require long data history intervals ranging over, in this case weeks or even months, before performing linear interpolation - gas trending is achieved by applying neural networks to compensate weather influences on sensor data. It is faster and more accurate, because the artificial intelligence model requires short historical data intervals of just few days. Additionally, all analyzed data can be monitored via smartphone or any other mobile device. Warning and alarm notifications can be pushed instantly to the mobile devices.
Operators and the environment benefit from mobile gas density monitoring
Grid operators benefit from reduced SF6 emissions, cost savings for unplanned SF6 leakage repairs and less risk contingencies and penalties for SF6 emissions. Sensgear® supports the operator by reducing maintenance frequency, resulting in less manhours on equipment and reduced site travels plus the opportunity to easily grant and revoke access to external service personnel.
SF6 monitoring via Sensgear® reduces manual legal reporting efforts and risk contingencies of potential penalties for SF6 emissions, which could have been avoided.
We are not stopping here! In fact, we are leveraging the power of a cloud platform and data in a substation environment. The next step for Sensgear® is to enhance intelligence with digital twin operation. This will allow operators to actively overload switchgear, based on real and virtual sensor information.Dr. Ulf Katschinski, Siemens Energy’s Vice President of the Switching Products business unit
UN sustainability goals
As a leader in innovative and sustainable products, Siemens Energy Transmission is supporting the implementation of the United Nations Sustainable Development Goals. With biodegradable ester insulating fluids for step-up transformers, dry-type transformers and clean air insulation for gas-insulated switchgear we support the implementation of goals number 3 “good health and well-being”, 7 “Affordable and clean energy”, 8 “Decent work and economic growth”, 9 “Industry, innovation and infrastructure", 11 “Sustainable cities and communities”, 12 “Responsible Consumption and Production”, 14 “Life below water” and 15 "Living on land".
