It is estimated that in the USA alone, tens of millions
pole top transformers are not equipped with internal
fault visual indicators, thus putting in danger the lives
of personnel maintaining the distribution network.
The InsuLogix® RFM is the only retrofittable pole
top transformer fault detector designed to help the
linemen determine if the transformer has an internal
The primary function of the InsuLogix® RFM is to provide
a visible external indication when arcing occurs inside
the transformer tank. The device’s red indicator serves as
confirmation that a fault has occurred within the transformer,
and the unit should not be re-energized for safety reasons.
The InsuLogix® RFM is sensitive enough to detect a pressure
increase due to internal low energy arcing which can result
from partial discharge, or high energy arcing resulting from
short circuits between phases or between phase and ground.
The InsuLogix® RFM will never activate during transformer
testing, transport, or installation; and comes equipped with
a pressure relief valve for release of internal tank pressure
manually or automatically.
The InsuLogix® RFM operates with a bellows mechanism
resistant to vibration and temperatures. Each device is
individually tested with five consecutive tests at three
different pressure rates: 1.5, 5, and 14 psi/sec. Test
certificates are available with each release upon request.
Wide Calibration: For low energy arcs the flag triggers with
any slow and progressive increase of the internal pressure
of the transformer.
Reduced Calibration: This type of calibration is immune to
pressure increases due to temperature variation. Flag will
not trigger as a result of low energy arcs.
The InsuLogix® RFM can be used on pole-mount, pad mount
distribution transformers and voltage regulators. For voltage
regulators application the InsuLogix® RFM will be calibrated
at 4.5 psi.
INTEGRATION WITH SCADA
For operations that need information on pole top
transformer health transmitted in real time into the SCADA,
Weidmann has developed a solution consisting of a wireless
transmitter connected to the RFM. The RFM status can be
transmitted to SCADA via modem or a radio transmitter.
Moreover, where necessary, the transmitter can also
transfer information such as transformer temperature and
load. In the latter case, temperature and current additional
sensors are required. Such solutions are recommended
for pole top transformers located in highly populated areas
and/or feeding critical buildings such as hospitals, schools,
and government institutions. Contact Weidmann for more
information on the integrated solution.
Patented InsuLogix® RFM Overpressure Indicator
* Patent # US 10,345,367 Bl