This document discusses electromagnetic interference (EMI) on large wind turbines. It describes the key components of wind turbines, including blades, hubs, and control systems. Control systems are especially sensitive to EMI since they use GSM transceivers. Large, high power turbines require more complex electronic systems and produce higher electromagnetic fields. EMI occurs through near field effects, diffraction and reflection/scattering from the rotating blades. Proper electromagnetic shielding of control systems, generators and blades is needed to reduce EMI and protect electronic components. Shielding effectiveness can be reduced by cable connectors or ventilation slots.

1. Yogesh Solunke
CDS14M011
Electromagnetic Interference on Large
Wind Turbines
5/11/2015 1

2. Wind Turbine
• A wind turbine is the popular name for a device that converts kinetic
energy from the wind into electrical power.

3. Large Wind Turbines
• It consist of
1. control system(GSM control system)
2. Wings(blades)
3. Hub

4. Control system
• Control system is most sensitive part of wind turbine
• A GSM 900MHz transceiver system installed to the hub
would allow operators to access the control systems
• Control over
1. Sharing data or power with their environment and the
other system operator
2. The rotational speed of the rotor and generator.

5. High power turbine
• Produces high power or electric power at the output
(in thousand’s of KW)
• For that purpose recently turned to more complex turbines to
capture power over a wide range of wind speeds and to increase the
power of the turbines so
• These turbines require more
1. electronic or control systems
2. GSM Transceiver
3. Rotors

6. Wind turbines (WT) cause EMI via three principal
mechanisms
• Near field effects
• Diffraction
• Reflection/scattering

7. Near field effects
• Near field effects refer to the potential of a wind turbine to cause
interference to radio signals due to electromagnetic fields emitted by
the generator and switching components in the turbine

8. Diffraction
• Diffraction occurs when an object modifies an advancing wave by
obstructing the wave’s path of travel.
• Diffraction effects can occur when the object not only reflects part of
the signal, but also absorbs the signal

9. Reflection/scattering interference
• Reflection/scattering interference occurs when turbines either reflect
or obstruct signals between a transmitter and a receiver.
• This occurs due to rotating blades of a turbine receive signals.
• In this situation the receiver may pick up two signals simultaneously,
with the scattered signal causing EMI because it is delayed in time
(out of phase).

10. EMI in Wind Turbine Control Systems
• The critical elements of a wind turbine affected by electromagnetic
fields is Control systems inside the hub(GSM 900 MHz Transceiver)
• Most EMI is caused by frequencies that fall between 1 kilohertz and
10 gigahertz, and this range is known as the RFI band,

11. Electromagnetic Shielding
• It is one of the most important tools in the area of electromagnetic
compatibility (EMC)
• Shielding require to
1. Control System Devices
2. Generator : Near field effect reduce
3. Blades: Over come Reflection/scattering

12. Shielding Effectiveness ( )
• The factor that expresses the attenuation caused by scattering during
its passage through a medium
• Due to cable connectors or ventilation slots, represent weaknesses in
the shielding devices.
• Electric and magnetic fields are able to penetrate into the shielded
space
• Over-voltages and currents are induced into the electric circuits and
may lead to the destruction of circuit elements

13. Path of field in Shielding

14. REFERENCES
• “ Electromagnetic Interference on Large Wind Turbines “
Florian Krug and Bastian Lewke , Published: 20 November 2009
• “EMC ISSUES FOR WIND TURBINES” by
M.C. Esteban , F. Arteche, M. Iglesias and FJ. Arcega
• http://www.learnemc.com
• http:// www.Google.com