Presentation - POWER TRANSFORMERS: Saturation ...
Presentation - POWER TRANSFORMERS: Saturation ...
Presentation - POWER TRANSFORMERS: Saturation ...
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<strong>POWER</strong> <strong>TRANSFORMERS</strong>:<br />
<strong>Saturation</strong> Compensation Modeling,<br />
Simulation, and Experiments<br />
John Thomas, Dr. David Cope<br />
Engineering Matters, Inc.<br />
23 Farwell Street<br />
Newton, MA 02460<br />
www.engineeringmatters.com<br />
14 October 2003<br />
1
Engineering Matters ®<br />
Short Form Resume<br />
• Incorporated 1998<br />
• Woman-Owned Small Business<br />
• Won several Phase I and Phase II SBIRs<br />
• Electromechanical Focus<br />
– Specialty motors, robotics, electromagnetic<br />
signature control and analysis<br />
• Direct drive force feedback joysticks<br />
– Several patents received<br />
– Three high-performance versions available<br />
• Ansoft user since 1984.<br />
Engineering Matters ® 2
Engineering Matters ®<br />
Design & Analysis Expertise<br />
• Electromagnetics<br />
– Motors<br />
– Actuators<br />
– Sensors<br />
• Electrical design<br />
– Power<br />
– Analog and digital<br />
design<br />
• Systems integration<br />
• Mechanical design<br />
– Prototype<br />
– Design for<br />
Manufacturing<br />
• Software design<br />
– Firmware<br />
– GUI/API<br />
– Computer interfacing<br />
• Control design.<br />
Engineering Matters ® 3
Power Transformer <strong>Saturation</strong><br />
Progression<br />
• Large scale common mode transformer currents, through<br />
a series of physical interactions, cause many deleterious<br />
effects. In some notable cases, these effects have led to<br />
total system collapse.<br />
SMD<br />
EMP<br />
ESP<br />
σ<br />
SMD = Solar Magnetic Disturbance<br />
EMP = Electromagnetic Pulse<br />
ESD = Earth Surface Potential<br />
GIC = Ground-Induced Currents<br />
VAR = Volts-Amps Reactive<br />
GIC<br />
Harmonics<br />
Engineering Matters ® 4<br />
B<br />
HEAT<br />
VAR<br />
H
Reasons for interest in<br />
transformer saturation<br />
• Transformer DC current<br />
causes half-cycle<br />
saturation, generation of<br />
harmonics, over-heating,<br />
increased audible noise,<br />
and mechanical stress.<br />
• Results in decreased<br />
transformer life.<br />
DC Flux<br />
Offset<br />
φ(t)<br />
t 1 t 2 t 3<br />
t 4 t 5 t 6<br />
Engineering Matters ® 5<br />
t<br />
t 1<br />
t 2<br />
t 3<br />
B(H)<br />
t 4<br />
t 5<br />
t 6<br />
t<br />
H<br />
I mag
Ground-Induced Currents (GIC)<br />
• Solar Coronal Mass<br />
Ejections (CME) affect<br />
utility operations<br />
– Generates an Earth-surface<br />
potential (1-10 V/km)<br />
– Drives a quasi-DC ground<br />
current (10-100A DC)<br />
– Duration 2-4 hours.<br />
• HEMP effects are more<br />
intense than CME effects<br />
– 10X voltage (10-100 V/km)<br />
– 10X current (~1000A DC)<br />
– 10-15 minutes/burst.<br />
Two Causes:<br />
Image credit: NASA<br />
I<br />
I/3 I/3<br />
I/3<br />
Engineering Matters ® 6<br />
I<br />
I/3 I/3<br />
I/3<br />
I
Solar Magnetic Disturbances<br />
• Solar magnetic<br />
disturbances<br />
(SMD) emit<br />
coronal mass<br />
ejections (CME)<br />
that interact with<br />
the earth’s<br />
magnetic field.<br />
Image credit: NASA<br />
Engineering Matters ® 7
SMDs follow the<br />
11 Year Sunspot Cycle<br />
Measurement<br />
period<br />
March 2003<br />
Image credit: Meteorological Satellite<br />
Applications Branch, Air Force Weather Agency.<br />
Engineering Matters ® 8
Overall Electrical Schematic for<br />
Source<br />
Energy<br />
Storage<br />
60 Hz Filter<br />
GIC Compensation<br />
3φ Generator<br />
a b c<br />
GSU XFMR<br />
Y-Y XFMR<br />
Transmission Line<br />
GIC injection<br />
(simulated)<br />
GIC injection<br />
(simulated)<br />
GIC injection<br />
(simulated)<br />
Earth ground<br />
Single<br />
Phase<br />
XFMR<br />
Single<br />
Phase<br />
XFMR<br />
Single<br />
Phase<br />
XFMR<br />
Phase A<br />
Load<br />
Tertiary Winding<br />
Phase B<br />
Load<br />
Tertiary Winding<br />
Phase C<br />
Load<br />
Tertiary Winding<br />
GIC Compensation<br />
GIC<br />
Compensation<br />
GIC Compensation<br />
Engineering Matters ® 9
Ansoft Maxwell ® & Simplorer ®<br />
• Three cases:<br />
(1) No GIC (before),<br />
(2) GIC (during),<br />
(3) GIC with<br />
compensation (after)<br />
• Maxwell 2D<br />
nonlinear Model<br />
• Simplorer Model<br />
– Block diagram &<br />
circuit simulation<br />
– Post processing<br />
analysis.<br />
Modeling<br />
Engineering Matters ® 10
Maxwell-Simplorer Linkages<br />
Nonlinear Transformer Model<br />
Engineering Matters ® 11
Simplorer Block Diagram<br />
Functionality of three circuits<br />
(PLL, time delay switch, op-amps)<br />
Engineering Matters ® 12
Simplorer Results: <strong>Saturation</strong><br />
Compensation Control<br />
Engineering Matters ® 13
Simplorer Results: Closed-loop<br />
Error Signal & Correction Current<br />
Engineering Matters ® 14
Simplorer Results:<br />
Post-processing FFT<br />
Before GIC<br />
I 2n ~0<br />
During GIC,<br />
large I 2n<br />
After GIC with<br />
Compensation<br />
I 2n ~0<br />
Engineering Matters ® 15
Maxwell 2D Results:<br />
Transformer |B| plots<br />
Before GIC During GIC<br />
After GIC with<br />
Compensation<br />
Engineering Matters ® 16
Sub-scale Mock-up Demo Unit<br />
• Sub-scale<br />
demonstration unit<br />
built & tested<br />
• Experimental<br />
measurements<br />
compared with<br />
simulation results<br />
Transmission<br />
Lines<br />
GIC<br />
Injection<br />
GSU XFMR<br />
Filter<br />
Filter<br />
Step-down<br />
XFMR<br />
Generator<br />
Load<br />
Compensation<br />
Circuits<br />
Engineering Matters ® 17
Sub-scale Unit Measurements:<br />
Error Signal & Compensation Current<br />
Engineering Matters ® 18
Sub-scale Unit Measurements:<br />
Primary currents for three cases<br />
Before GIC<br />
During GIC<br />
After GIC with<br />
Compensation<br />
Engineering Matters ® 19
Sub-scale Unit Measurements:<br />
FFT Harmonic Amplitudes<br />
Engineering Matters ® 20
Transformer <strong>Saturation</strong><br />
Compensation Summary<br />
• Natural & man-made events can cause transformer<br />
saturation which threatens power electric system<br />
stability and reliability<br />
• Regained transformer stability by automated<br />
measurement and compensation<br />
• Achieved very good comparison between<br />
simulations and experiments<br />
• Future work will extend SMPS capabilities to<br />
higher power and voltage. More modeling and<br />
simulation are needed.<br />
Engineering Matters ® 21
Additional Projects of Interest<br />
(designed with Maxwell® 3D)<br />
• Force Feedback<br />
Joystick (Direct drive,<br />
wide bandwidth, very<br />
rugged)<br />
• MEMS OXC actuator<br />
Engineering Matters ® 22
Robotic Design and System Integration—Power<br />
Electronics, Vehicle design, Test Plan; RC, Motor<br />
and Battery selection<br />
Engineering Matters ® 23
Acknowledgements<br />
The GIC-compensation project was<br />
developed with funding from the<br />
United States Army Space &<br />
Missile Defense Command<br />
Contract numbers DASG60-01-<br />
C-0017 and DASG60-02-C-0066.<br />
Engineering Matters ® 24
Unconventional Alternative<br />
• Geothermal<br />
• Wave-action<br />
• Human-effort<br />
Power Applications<br />
Engineering Matters ® 25
Bill Powell working out in<br />
Icelandic geothermal pool<br />
Engineering Matters ® 26
References<br />
• Introduction to Geomagnetic Fields, Wallace Campbell, Cambridge<br />
University Press, NY, 1997.<br />
• “Geomagnetic Storms and Their Impact on Power System,”<br />
Kappenman, John, G., IEEE Power Engineering Review, May 1996, p.<br />
5.<br />
• “Comparison of SS-GIC and MHD-EMP-GIC effects on power<br />
systems,” Meliopoulos, A.P.S.; Glytsis, E.N.; Cokkinides, G.J.;<br />
Rabinowitz, M. Georgia Inst. of Technol., Atlanta, GA, USA Power<br />
Delivery, IEEE Transactions on, Pages: 194-207 Jan. 1994 Vol. 9<br />
Issue: 1 ISSN: 0885-8977.<br />
• "Geomagnetically induced Currents during Magnetic Storms", R.<br />
Pirjola, Plasma Science, IEEE Transaction on, Vol. 28, No. 6, Dec.<br />
2000, p. 1867.<br />
Engineering Matters ® 27
Significant Power System<br />
Outages (GIC & Other)<br />
• GIC Storms:<br />
– February 1986, March<br />
1989, March 1991,<br />
November 1991 and May<br />
1992.<br />
• GIC-Utility Events (place,<br />
people affected, duration):<br />
– North America: April 1940,<br />
Sept. 1989, March 1991,<br />
Oct 1991<br />
– Quebec March 1989, 6M, 9<br />
hr. massive outage<br />
• General Outages (place,<br />
people affected, duration):<br />
– US August 2003, 50M, 16-<br />
20 hr.<br />
– London August 2003,<br />
1.5M, 1 hr.<br />
– Denmark & Sweden<br />
September 2003, 5M, 4 hr.<br />
– Italy September 2003, 57M,<br />
9 hr.<br />
Engineering Matters ® 28
March 13, 1989 GIC-related<br />
Image credit: Kappenman<br />
‘Events’<br />
Engineering Matters ® 29