Leakage Current Detection System for

1
Leakage Current Detection System for Insulated
Boom Trucks
The purpose of this project is to design a
system for testing the insulation integrity of
boom trucks while the boom is placed in contact
with a high voltage line. This system is to have
three modules or sub systems sensing, signal
encode including transmit, and signal receive
including display. With the present method,
linemen read a boom-mounted ammeter using field
glasses, while standing on the ground at a safe
distance from the truck. For this project, a
device will be designed, using the leakage
current sensed by the existing analog ammeter
which is then converted into digital form, and
transmitted to a handheld device, where it is
translated in a digital read out. This hand held
device is read by a lineman, standing a safe
distance from the truck. This will make reading
the leakage current easier, to verify the
insulation integrity of the boom. Safety of
linemen working from buckets must be assured by
keeping the leakage current below specified
values. -Utility Linemen -Equipment
Maintenance Personnel The device to be able to
withstand normal weather conditions and withstand
temperatures ranging from 30 to 185 degrees
Fahrenheit. -The measured leakage current will
range from 0 to 2000 microamps. -The receiving
end will be within 100 feet of the boom
truck. -The duty cycle is limited to the battery
life. -The boom truck will only be in contact
with one line at a time. -The Leakage Current
Detection System is working correctly. -The KV
value and allowable leakage current are known for
the line. -Lab Testing Includes operational
testing of the sensor, transmitter, and
receiver for functionality and accuracy. -Field
Testing The device will be given to the client
to be tested in a real world
environment. -Total estimated cost
1000 -Total estimated team effort 623 hours
Design a radio frequency (RF) system to transmit
data from the top end of the boom to a remote
hand held device on the ground. This RF system
will utilize the existing leakage current sensor
in analog form, then convert it to a digital
signal that will be transmitted to a hand held
device about 100 feet away. This receiving
module will display the leakage the current or
some system message (i.e. Low Battery) the
resultant leakage current data will verify safety
degree of the truck and boom.     The new system
will measure the insulation integrity of the boom
and truck to provide the same safety information
as the existing system, with no change in the
safety concept. This system could also be used in
various field locations as well as in laboratory
settings.     The new system will consist of a
leakage current sensor, from the existing system,
together with an analog to digital converter,
plus a transmitter and hand held display device,
capable of operating within 100 feet of the point
of contact with the high voltage line. This will
eliminate the need for field glasses and the
large meter display. The system will also be
easily tested to ensure proper readings in the
field. The new system will not add significant
size to the existing hardware to keep it mobile
and easily adaptable to the existing system. It
will also have to be durable to withstand normal
temperature and weather conditions. The new
device will also have to be powered by batteries
and add no more than 100 to the existing
system. -Interface with current unit This
will be judged by successful integration with the
current probe assembly. -Data Input to
programmable unit This will be judged by the
successful input of the measured current signal
into the programmable logic unit. -RF
Transmission/Reception This will be determined
by a successful transmission and receiving of a
digital bit stream. -Receiver/Display Interface
This will be successful upon the completion of
the system to decode and display data.
Boom and Truck Being Tested
Typical Boom Truck
Boom Truck Controls
Acceptable Leakage Current Values
Present Current Detecting and Display Device
New Current Detecting, signal Transmitting and
Display System
Team May01-12
Client Skarshaug Testing Laboratory, Inc.
Ames, IA
Team Members Joshua Struble (EE), Elijah Forney
(EE), Thuy-Linh Nguyen (EE), Christopher Hulsebus
(EE) Advisors Glen Hillesland, John Lamont,
Robert Weber