Deep Dive: SF6 Gas Monitoring

Mar 21, 2022 | substations , breakers , Utilities
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With its high density, SF6 gas is an excellent dielectric medium insulator for circuit breakers. It allows the interruption of high voltages to be done in a very confined space, and in a very short time. Unfortunately, SF6 is also a very potent greenhouse gas, 23,000 times more damaging than carbon dioxide. The EPA has regulations regarding the release of SF6 into the atmosphere, requiring utilities to report their SF6 use and any losses annually. Monitoring for this gas in circuit breakers is vital to ensuring both circuit breaker performance and EPA compliance.

What Are the Different Types of SF6 Gas Monitoring?

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SF6 Gas Density Sensor

Measures both temperature and the true density of SF6 gas.

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SF6 Gas Pressure Sensor

Measures both the temperature and the Temperature-Compensated Pressure of SF6 gas.

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SF6 Gas Dew Point Sensor

Measures the moisture content of SF6 gas.

How Does it Work?

In a circuit breaker, the pressure of the SF6 gas must be maintained, so that the proper density is maintained, and the insulating properties are sustained. The Optimizer3 Circuit Breaker Monitor is capable of constantly measuring the SF6 gas density, pressure and temperature, and will assert an alarm if the pressure or density is too low. Low gas density and excess moisture can seriously compromise the insulating properties of SF6, which can lead to a catastrophic failure. The Optimizer3 will detect and trend any SF6 leakage and provide an early warning, long before damage occurs. The moisture content of the SF6 gas can also be monitored using a Dew Point Sensor. 

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How Are Sensors Installed?

Regardless of the breaker type, installing an SF6 sensor is easy. Sensors can be installed directly into the pipe feeding a pressure gauge, into the breaker’s SF6 fill port using INCON® Fill Port Adapters, or into a breaker’s accessory port.

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SF6 Gas Sensor Fill Port Adapters

SF6 Gas Sensor Adapters allow the range of sensors to be directly connected to a circuit breaker via the SF6 gas fill port. Integrated check valves and O-Ring seals facilitate a tight connection, mitigating the risk of a gas leak.

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SF6 Gas Humidity Absorber

The SF6 Gas Humidity Absorber is capable of passively absorbing up to 40 milliliters of water from SF6 gas, saving major expense compared to standard circuit breaker moisture removal. The corrosion-resistant absorber is easily connected to a circuit breaker’s SF6 gas port.

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Optimizer3 Circuit Breaker Monitor

The INCON® Optimizer3 Circuit Breaker Monitor delivers advanced automated reporting of all critical circuit breaker diagnostics to ensure uptime and facilitate predictive maintenance. The Optimizer3 is ideal for high-voltage, live or dead-tank, oil, vacuum, or gas circuit breakers. 

The Optimizer3 and its array of sensors deliver a complete diagnostics report of a circuit breaker’s performance.


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