17-1

EE 442-642

Electric Utility Applications

17-2

HVDC Transmission

17-3

HVDC Poles

sin35.1,cos35.1

,3

cos23

11

21

dLLddLLd

ds

LLdd

IVQIVP

IL

VVV

17-4

HVDC Transmission: 12-Pulse Idealized Waveforms

17-5

HVDC Transmission: Inverter Mode

17-6

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

17-7

HVDC Transmission: DC-Side Filters Tuned for the lowest (12th harmonic) frequency

17-8

HVDC Transmission: AC-Side Filters Tuned for the lowest (11th and the 13th harmonic) frequencies

17-9

Effect of Active and Reactive Current on Voltage Magnitude

17-10

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

17-11

Thyristor-Switched Capacitors (TSCs)

Transient current at switching must be minimized

17-12

Instantaneous VAR Controller (SATCOM)

Can be considered as a reactive current source

17-13

Photovoltaic Grid-Tied Inverter

This scheme uses a thyristor inverter

17-14

Harnessing of Wing Energy

17-15

Interface of SMES

Can be used for utility load leveling

17-16

Active Filters for Harmonic Elimination

Active filters inject a nullifying current so that the current

drawn from the utility is nearly sinusoidal

17-17

Utility Interface – Power Quality

PCC is the point of common coupling

17-18

Diode-Rectifier Bridge Harmonic Content

17-19

Harmonic Guidelines: IEEE Std. 519

commonly used for specifying limits on the input current

distortion

17-20

Harmonic Guidelines: IEEE Std. 519

Limits on distortion in the input voltage supplied by the utility

17-21

Reducing the Input Current Distortion of Diode Bridge

Rectifier with Passive Filters

17-22

Power-Factor-Correction (PFC) Circuit

For meeting the harmonic guidelines

17-23

Power-Factor-Correction (PFC) Circuit Control

17-24

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.

17-25

Switching Waveforms

• Typical rise and fall times

17-26

FCC and VDE Compliance Curves

17-27

17-28

Conducted EMI

Typical EMI filter arrangement