Fluke Ti450 SF6 User Manual

APPLICATION NOTE

Why SF6 gas detection matters
in utilities

Sub-station equipment including circuit breakers and transformers,
switch and transform high voltages and currents. The switching
of such high voltages poses a risk to safety and production in the
form of an arc flash. SF6 gas is used for insulation purposes in
this equipment. Indeed, this greenhouse gas is a more efficient
alternative to insulators such as air and oil, due to its ionization
properties as a quenching gas. However, as a potent greenhouse
gas it is important to ensure that in the event of a gas leak, it is
detected and dealt with appropriately.

Figure 1. An inspector uses the Fluke Ti450 SF6 Gas Detector to
inspect bolted connections.

Using SF6 gas requires that
utilities have a process in place
to track the amount the utility
uses and what amount of gas
is leaked into the atmosphere.
The best choice to address this
is to have a reliable infrared
camera with SF6 gas detection
for spotting possible leakage
during day-to-day mainte­nance rounds. This is where
the rugged Fluke Ti450 SF6 Gas
Detector enters the picture, as
it’s a more affordable infrared
camera solution. Using the Fluke
Ti450 SF6, utilities professionals
can perform thermal inspections
to detect leaks of varying signif­icance, reduce downtime, and
schedule appropriate repairs to
the welds or bolted connections
(seals and flanges) of bushings.

The importance of SF6
gas detection

SF6 gas is used to insulate out­door substation equipment with
higher than 35,000 volts (with
corresponding high current) in
utilities such as circuit break­ers, transmission line switches
and underground distribution
switches or devices. If air or
moisture sneaks inside the
equipment, catastrophic failure
like an arc blast can ensue.
SF6 gas helps prevent such
calamities but the gas itself

carries some downsides and
needs to be contained within
the equipment enclosures. Each
country will have their own
set of regulations. In the United
States, the Environmental Pro­tection Agency (EPA) requires
utilities to have a process in
place to regularly monitor SF6
gas leakage. Fluke advises that
you research and familiarize
yourself with your country and
local regulations.

The minimum requirements for
utilities is to have a process in
place to monitor SF6 gas use
and leaks. California is the only
state that requires the utility
to record SF6 gas usage and
leak rate on an annual basis,
achieving transparency through
reporting and thorough record­keeping. If the gas leak is more
than 1 % of the total gas used
across the company, the EPA
can fine the company. Utilities
can be randomly audited by the
EPA during which the govern­ment organization checks a
facility to determine if a SF6
monitoring process is both in
place and effective enough
in accordance with reducing
greenhouse gas emissions.

The Fluke Ti450 SF6 rein­vents the bar for everyday
inspection rounds, combin­ing infrared and gas detection

8 tips to capture gas images

Figure 2: A thermal image with gas detection overlaid on a visible light image of a circuit
breaker.

• Avoid rainy/windy days–under these condi­tions gas dissipates too fast unless a massive
leak is present

• Gas needs to be a different temperature than
your background to see–you need a thermal
contrast:

– Cold sky or heated control box
– Emissivity is a factor–make sure you plan

for it

• Use a tripod to stabilize the camera during
inspection

• Place the camera 10-12 feet from the target

• Position your camera lower than the leak and

point the camera up – take advantage of the
cold sky when you can, as gas leaks out in
blurbs, not straight lines

• Be patient–wait for the gas

• Common leak locations are flanges, top and

base of bushings, tubes

• When you find the leak, remove the camera
from the tripod to get closer or move it to a
better angle to get a better image

in one cost-effective tool. This infrared camera
combines the Fluke Ti450, a high-performance
thermal imager with a dependable pistol grip
form factor, and SF6 gas detection. It empowers
inspectors to locate gas leaks without taking
equipment offline and monitor equipment from a
safe distance. The Ti450 SF6 sports an intuitive
interface that seamlessly switches between stan­dard thermal imaging and gas imaging modes.

A utilities inspector lacking a thermal imaging
camera with SF6 detection capability might find
it difficult to pinpoint the exact location of the
leak. Unfortunately, the all-too-common solution
is to shut down the equipment and replace or
repair all joints or points where the leak could be
occurring just to be safe and in total compliance
with government regulations. The Ti450 SF6
helps avoid expensive and potentially unnec­essary equipment repairs. The camera offers
confident leak detection and can help locate
the source of a leak more effectively than other

methods.

How utilities locate leaks

The current protocol for detecting a leak is rather
cumbersome. A pressure gauge is used to indicate
if there is a loss of gas. For a known SF6 loss, the
gas canister used to top up the SF6 is weighed
before and after to determine how much gas has
been lost/leaked. Periodic inspections and top­ping up informs the utility of the rate of the gas
leak. Depending on the rate of the gas leak the
utility will adopt different strategies to deal with
the leak. Before taking any remedial action, the

2 Fluke Corporation Why SF6 gas detection matters in utilities