Department of Engineering, CCSU Northeast Utilities 

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115 KV Power Line Electromagnetic Interference Field Testing

Engineering and Safety Study

Alfred A. Gates, Ph.D., P.E.

Department of Engineering, CCSU

Abstract

An engineering and safety study, involving power line electromagnetic interference, 

was developed and implemented for unmanned aircraft system, UAS, flight next to 

115KV power lines. Four unmanned aircraft systems were tested for 

electromagnetic interference from 115 KV lines. The unmanned aircraft systems 

were positioned on a platform next to 115KV power lines and support structures. 

The autopilot system of each UAS was tested and evaluated. The test set up 

consisted of a multi axis tether platform that each UAS was secured to. The 

platform allowed the UAS to hover in any orientation at a maximum height of three 

feet from the platform. If the UAS became uncontrollable, the tether system will

prevent the aircraft from crashing and allow the pilot to land the aircraft with no 

damage to the aircraft or property, on the platform. The flight testing was successful 

and the four UAS aircraft are capable of flight within three feet of 115KV power 

lines. This report will review the testing of one of the aircraft, the Draganflyer X4-

P. 

Introduction

Currently power line support structures are inspected for damage due to wild life 

habitation, corrosion, weather and vandalism. The current process of support 

structure inspection involves the use of a bucket truck and crew of highly skilled 

line workers. To inspect a support structure a bucket truck is driven over terrain that 

sometimes only four wheel drive vehicles can make it through. In those cases road 

work is required to enable the bucket truck to make it to the support structure. Next 

the area next to the support structures will have to be cleared and checked and 

leveled for a proper foundation to support the support legs from the bucket truck. 

Finally the support structure can be inspected and a determination made of the 

quality of each support structure. Another method of support structure inspection 

involves personnel climbing the support structure and performing the inspection. 

Each method is time consuming and potentially dangerous.

A new method of support structure inspection is proposed that involves the use of 

unmanned aircraft systems, UAS. The UAS would be operated with in visual 

distance from a pilot/operator and observer. A pilot would fly a UAS up to a 

support structure and hover it in a position within 10 feet of a location that is 

potentially damaged. The UAS would have a video system on board which would 
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be used to provide a close up view of the support structure potential damage. The 

UAS would be flown in GPS position hold mode. The UAS will hold position, 

whenever the pilot stops using the control sticks on a transmitter. This allows for 

safe flight next to objects such as power line support structures. 

The benefits of this procedure are savings in inspection time, reduction in 

environmental impact, reduction in personnel required and reduction in equipment 

necessary for the inspection. Additional benefits include the development of a video 

database of the support structures use as a baseline for comparison. Also the 

inspection process time would be significantly reduced.

An engineering and safety study is necessary to determine if the electromagnetic 

field interferes with the onboard electronics of UAS aircraft. Also different 

airframes and or electrical wiring to the motors of each UAS may change the 

electromagnetic field around the onboard electronics. 

The aircraft selected for this experimentation is a multicopter specifically called a 

quadcopter. The quadcopter has four arms supporting motors and propellers, figure 

1.0. The Draganflyer X4-P electronics that would be used for power line inspection 

are; flight controller, inertial measuring unit, telemetry radio, GPS, receiver and 

transmitter radio, and video transmitter. 
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Figure 1.0, Draganflyer X4-P, Multicopter (Quadcopter) and Transmitter

The make of the UAS aircraft for testing is a Draganfly and the model of the 

aircraft is the Draganflyer X4-P

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, figure 1.0 and 2.0. The X4-P UAS airframe is 

made of carbon fiber with a high resistance coating. If the coating is scratched the 

resistance of each arm is reduced to 500 Ohms. Also the propellers are made of 

carbon fiber and have a similar coating. A ground control station was also used in 

the 115 KV power line testing. The ground control station provided the telemetry 

from the aircraft and has an attitude indicator along with a compass heading of the 

aircraft. The attitude indicator and magnetic heading indicator can be used to 

monitor the effects of an electromagnetic field. If a magnetic field interferes with a 

UAS either the attitude indictor and or the magnetic heading indicator will fail. 

This aircraft along with three other aircraft were tested for electromagnetic

interference with the flight stability and position holding capability. This report 

covers the results of the Draganflyer X4-P aircraft.

Figure 2.0, Draganflyer X4-P Quadcopter Electronics

115 KV Power Line Test Platform

Platform tethered flight test were performed using the Draganflyer X4-P aircraft. 

The test apparatus was a wood structure, secured to a non-grounding power line 

bucket. The test apparatus allowed the quadcopter UAS to hover in any orientation 

at a maximum at a height of up to three feet from the platform, figure 3.0. The test 

platform can also be suspended from a crane, figure 4.0. The maximum pitch and or 
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roll angle the tether platform would allow is approximately 45 degrees. The pitch 

and roll degrees of freedom is accommodated by a universal joint gimbal, figure 

5.0. The aircraft can yaw in either direction and the rotation about the yaw axis is 

unlimited. This tether platform was designed to constrain the UAS in the event of 

any type of malfunction. In all modes of flight the quadcopter will never experience 

pitch and or roll angles greater than 25 degrees. The platform was tested at another 

location to ensure that there was no possibility of damage to the aircraft, platform 

and nearby property by purposely orienting the aircraft at pitch and roll angels 

greater than 25 degrees. Figure 4.0 displays a quadcopter in a tethered hover in the 

suspended platform. 

Figure 3.0, 115 KV Multicopter Test Platform, Mock Testing
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Figure 4.0, 115 KV Multicopter in a Suspended Platform and in a Tethered Hover
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Figure 5.0, Universal Joint Gimbal

Draganflyer X4-P Airframe Evaluation

The Draganflyer X4-P airframe has been examined for electrical resistance. The 

airframe and propellers are made of carbon fiber and are coated with a high 

resistance coating. The coating was scratched off in places and the resistance was 

checked and found to be 500 Ohms. Figure 6.0 provides an evaluation on the 

resistance of the Draganflyer X4-P airframe. 
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Figure 6.0, Resistance Evaluation, Draganflyer X4-P

115 KV Power Line Test Procedure

The test procedure involves securing the test platform onto the top of a bucket, 

figure 7. The multcopter is powered up and the multicopter is hovered on the 

platform, table 1. Also the telemetry is checked with the ground control station. 

Next the throttle is advanced to a setting slightly less than hover. The ground 

control station is checked and once all of the systems are operating correctly the 

multicopter on the test platform is moved within three feet of a 115KV power line. 

At three feet the electromagnetic field is constant and remains constant out to

approximately 5 meters (16.4 feet)2, figure 8. The telemetry is checked for any 

malfunctions. The multicopter is next hovered on the platform at a height up to 

three feet from the platform for approximately one minute. Following the hover the 

multicopter is landed on the platform and the throttle is set slightly less than hover 

throttle. The multicopter held in position for approximately 10 minutes. Finally the 

multicopter is hovered in the fixture for approximately a minute. After that the 

multicopter is landed on the platform and the throttle is again set to slightly less 

than hover and the bucket is moved to the ground. Once the bucket is stabilized on 

the ground the multicopter is hovered above the platform for several minutes. 

Throughout this process the ground control station is monitored for any 

malfunctions and the video monitor is watched for any abnormal activity from the 

multicopter. 
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Figure 7.0, Draganflyer X-4P Mounted on the Test Platform

Figure 8.0, Typical Electromagnetic Field around Different Power Lines, National 

Grid EMF help Line2
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Table 1, 115 KV Power Line Test Procedures

Install hover platform on bucket and secure multicopter 

Turn on multicopter and ground control station

Check telemetry on ground control station

Hover multicopter on platform and check telemetry

Set throttle slightly below hover throttle and hold

Move bucket to position three feet next to 115 KV lines

Hover multicopter in place at approximately three feet from platform for one 

minute

Set throttle to slightly lower than hover power (monitor telemetry and record 

errors)

Wait 10 minutes in position (monitor telemetry and record errors)

Hover multicopter for one minute (monitor telemetry and record errors)

Land multicopter on platform and set throttle to slightly less than hover power

Move bucket back to ground 

Hover multicopter at three feet over platform for several minutes (monitor 

telemetry and record errors)

Shut down aircraft and remove platform

115 KV Power Line Test Results

The 115 KV power line test was performed at Grandville Mass on December 19, 

2013, figure 9.0. The tests were conducted as planned, table 1, by placing the 

Draganflyer X4-P on a platform mounted on a bucket, figure 7.0. 

Figure 9.0, Grandville Mass 115 KV Power Line Support Structure 
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Photos of the positioning of the bucket next to the 115KV power lines are displayed 

in figure 10.0. The platform with the Draganflyer X4-P was positioned in-between

two 115 KV power lines as well as within three feet of a 115 KV power line.

Figure 10.0, Movement of the Platform within Three Feet of 11 KV Power Lines

Figure 11.0 provides a picture of the video display monitor used to hover the 

Draganflyer X4-P on the platform next to the 115 KV power lines. Also the 

Draganflyer X4-P ground control station displayed in figure 12.0 was used to 

monitor the telemetry from the multicopter. During all of the procedures the ground 

control station provided normal telemetry output from the multicopter, table 2. 

There were no abnormalities due to the electromagnetic field. Also the video

displayed normal operations of the Draganflyer X4-P during all phases of the test. 

Figure 11.0, Video Monitor
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Figure 12.0, Draganflyer X4-P Ground Control Station

Table 2, Draganflyer X4-P Telemetry Data
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Conclusion

An engineering and safety study was performed for electromagnetic interference 

from 115KV lines. The Draganflyer X4-P was tested on a platform attached to a 

bucket within three feet of a 115 KV power line. The platform allowed the 

Draganflyer X4-P to hover at an altitude of three feet above the platform at any 

orientation. The telemetry was viewed from a ground control station and displayed 

normal data for the duration of the testing. Also a video system was used to view 

the Draganflyer X4-P at all times during the testing. The video also displayed 

normal operation of the X4-P during all of the testing phases. The results of the 

tests indicate that the electromagnetic field at three feet or more from 115 KV 

power lines does not interfere with the Draganflyer X4-P controller, inertial 

measuring unit, magnetic compass, transmitter, receiver or GPS.

References

1) Draganfly Inc., http://www.draganfly.com/uav-helicopter/draganflyer-x4es/index.php

2) National Grid EMF help Line, 

http://www.emfs.info/Sources+of+EMFs/Overhead+power+lines/
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Appendix A

C E N T R A L

CONNECTICUT STATE UNIVERSITY

_________________________________

1615 Stanley Street P.O. Box 4010 New Britain, CT 06050-4010 www.ccsu.edu

4/16/14

To: Skip Wiegand

AEA 220 UAS

Federal Aviation Administration

From: Alfred A. Gates

Subject: 115KV Line SUAS Line Testing

References: Email From Skip Wiegand Dated 4/8/14

The answers to your questions are:

1) The 115KV Power line Electromagnetic Interference testing was done on Thursday 12/19/13. 

The line was energized with a voltage of 115KV and a current flow of 24.9 Amperes. 

2) The bucket truck used is a non-grounded High Voltage (HV) Barhand bucket which is used 

for live line maintenance and is tested for work up to 500KV. Before the truck can be used 

the bucket is tested to insure there is no leakage to ground by moving the bucket into a 

position where it makes contact with the power lines and checking the current flow using a 

permanently installed meter at the base of the aerial lift. 

3) All personnel involved with the experimentation were fully qualified high tension line 

workers from PAR Electrical Contractors working for Northeast Utilities satisfying all 

OSHA requirements. 

4) All personnel involved with the experimentation were on the ground during all phases of the 

testing. No personnel were in the bucket during the experimentation. The quadcopters X4-P 

was mounted to a tethered platform. The hovering flight was controlled by watching a 

wireless video monitor from a camera mounted on a wood pole a ways from the quadcopters, 

see figure. 

5) The testing procedure was approved by the supervisor on site and met all safety issues. The 

wood platform and tether system was found to be acceptable and did not cause an arc since 

the platform is electrically isolated by the Barhand bucket.
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6) For the quadcopter to cause an electrical short, or arc, it would have to be grounded. The 

quadcopters was always electrically isolated by the Barhand bucket. If the quadcopter came 

in contact with a power line nothing would happen to the airframe since the airframe is not 

grounded. The quadcopter frame voltage would become the same as the line voltage in the 

event of a contact. This would be similar to a bird landing on a power line.

7) Wood has a very small electrical conductance compared to aluminum, steel and other metals 

and carbon fiber. We had to be very careful to not generate current through the platform and 

tether system. We also used plastic parts where possible to minimize any current flow. 

8) Current flow will occur through conducting bodies such as carbon fiber frames when they are 

in the proximity of an electromagnetic field. If we used a conducting platform and tether 

system then the current flow through it could of altered our experimental results. This test 

addressed the effects of current flow through the quadcopter’s carbon fiber frame in addition 

to the electromagnetic field around the power lines.

Quadcopter Tether Test Platform Mounted to Barhand Bucket

Sincerely

Alfred A. Gates

Central CT State University

1615 Stanley Street, New Britain, CT 06050

Copernicus Hall Room 2350920

Phone: (860) 301-2117, Email: gatesa@ccsu.edu