Moisture can significantly impact the performance of SF₆ gas in electrical equipment. Maintaining low moisture levels in SF₆ gas is crucial for ensuring the reliable operation of electrical equipment. Regular testing and monitoring of moisture content, along with proper maintenance practices, are essential to prevent the adverse effects of moisture on SF₆ gas performance. We can learn from below aspects.
1. Insulation Strength Reduction
Excessive moisture in SF₆ gas can lead to a decrease in its insulation strength. This is critical because SF₆ is widely used in high-voltage electrical equipment due to its excellent insulating properties. When moisture content exceeds certain levels, it can compromise the dielectric strength of the gas, increasing the risk of insulation failure 1.
2. Corrosion of Equipment Components
Moisture can react with SF₆ gas under certain conditions, especially in the presence of electric arcs, to form corrosive by-products such as hydrofluoric acid (HF) and sulfur dioxide (SO₂). These compounds can corrode internal components of the equipment, leading to degradation and potential failure over time 1.
3. Formation of Toxic Decomposition Products
When SF₆ gas containing moisture is exposed to electric arcs, it can decompose into toxic substances like SF₄, S₂F₂, SOF₂, HF, and SO₂. If these decomposition products are released into the environment, they can pose serious health risks, including respiratory issues and other toxic effects 3.
4. Impact on Flashover Voltage
High moisture content can affect the flashover voltage of solid insulating surfaces within the equipment. This means that the voltage at which an insulating barrier fails and an arc forms can be reduced, increasing the likelihood of flashovers and subsequent equipment damage 1.
5. Measurement Standards for Moisture Content
To mitigate these issues, strict standards are set for the moisture content in SF₆ gas. For instance, newly charged gas should have a moisture content not exceeding 150 parts per million (ppm) in the case of circuit breaker arc extinguishing chambers, while during operation, this value should not exceed 300 ppm 3
Our WS-2 SF6 gas moisture analyzer can help to measure the moisture content of SF6 gas, portable and high-performance. It is an idea analyzer for GIS or other SF6 gas electric equipment.