In summary, acoustic techniques are relatively cheap and simple to apply, are
utilised online and can detect the presence and location of discharges in the various
items of plant discussed. Their disadvantages include their inability to be applied
to intrinsically noisy plant, e.g. motors/generators, the need for the sensor to be
relatively close acoustically to the discharge source (so the technology cannot, for
example, be applied to cables) and their inability to be calibrated in terms of voltage
output versus size of discharge.