EE 442-642 Electric Utility Applications
Transcript of EE 442-642 Electric Utility Applications
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EE 442-642
Electric Utility Applications
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HVDC Transmission
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HVDC Poles
sin35.1,cos35.1
,3
cos23
11
21
dLLddLLd
ds
LLdd
IVQIVP
IL
VVV
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HVDC Transmission: 12-Pulse Idealized Waveforms
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HVDC Transmission: Inverter Mode
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Control of HVDC Transmission System
dc
dBdAd
R
VVI
Minimize Id to reduce I2Rdc losses → operate a minimum extinction angle γ
,3
cos23
ds
LLdB IL
VV
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HVDC Transmission: DC-Side Filters Tuned for the lowest (12th harmonic) frequency
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HVDC Transmission: AC-Side Filters Tuned for the lowest (11th and the 13th harmonic) frequencies
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Effect of Active and Reactive Current on Voltage Magnitude
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VAR Control: Thyristor-Controlled Inductor (TCI)
Increasing the delay angle reduces the reactive power drawn by the TCI.
L
VII s
LL
1
1
1 ,)2sin(22
L
seff
sL
I
VL
L
VI
eff
sLs
L
VIVQ
2
1
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Thyristor-Switched Capacitors (TSCs)
Transient current at switching must be minimized
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Instantaneous VAR Controller (SATCOM)
Can be considered as a reactive current source
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Photovoltaic Grid-Tied Inverter
This scheme uses a thyristor inverter
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Harnessing of Wing Energy
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Interface of SMES
Can be used for utility load leveling
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Active Filters for Harmonic Elimination
Active filters inject a nullifying current so that the current
drawn from the utility is nearly sinusoidal
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Utility Interface – Power Quality
PCC is the point of common coupling
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Diode-Rectifier Bridge Harmonic Content
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Harmonic Guidelines: IEEE Std. 519
commonly used for specifying limits on the input current
distortion
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Harmonic Guidelines: IEEE Std. 519
Limits on distortion in the input voltage supplied by the utility
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Reducing the Input Current Distortion of Diode Bridge
Rectifier with Passive Filters
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Power-Factor-Correction (PFC) Circuit
For meeting the harmonic guidelines
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Power-Factor-Correction (PFC) Circuit Control
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EMI: Conducted Interefence
• Common and differential mode currents
Electromagnetic interference (EMI) is disturbance that affects an electrical
circuit due to either electromagnetic induction or electromagnetic radiation
emitted from an external source. Anywhere electrical power is being turned off
and on rapidly is a potential source.
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Switching Waveforms
• Typical rise and fall times
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FCC and VDE Compliance Curves
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Conducted EMI
Typical EMI filter arrangement