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Premisas, objetivos, estrategia y restricciones
!!Premisa: charla ha sido preparada en respuesta a
solicitud de IEEE PES sección Chile
!!Objetivo: discutir aspectos básicos de la transmisión
de potencia eléctrica en corriente continua de alta
tensión y su potencial aplicación en Chile
!!Estrategia: descripción básica de la tecnología y de las
razones que la justifican con apoyo en material
preparado por el autor y otro disponible en la web de fabricantes: ABB, SIEMENS, AREVA/Alstom
!!Restricciones: sólo 45 minutos
!!Las opiniones son de Gabriel Olguín y no representan
necesariamente la de su empleador
Nota: Para una entretenida descripción de la guerra AC versus DC ver “AC/DC: The Savage Tale of the First Standards War” by Tom McNichol
HVDC is not a new technology!
First commercial HVDC transmission in
1954 (100 kVdc, 20 MW)
¿Que es HVDC?
!! HVDC es una opción tecnológica para la transmisión de grandes bloques
de potencia eléctrica sobre grandes distancias
!! Utiliza dispositivos de electrónica de potencia para lograr la conversión de
corriente alterna a corriente continua y vice versa
!! La transmisión de potencia se realiza en corriente continua lo que
posibilita costos por kilómetro de línea menores que en el caso de
corriente alterna
!! Los bloques de potencia a transmitir son de miles de MWs
Sistema
AC 1
Sistema
AC 2 Trasmisión en CC Convertidora
AC<=>CC
Convertidora
CC<=>AC
Transmisión expresa de potencia eléctrica sobre una
distancia de ~700 a 2300km
HVDC 2 Technologies
1.- HVDC Classic 7000 MW, 800kV
!! Thyristor controlled
!! Switched Reactive Power Control
!! Typical design valve building plus
switchyard
!! Mass impregnated cables
2.- HVDC VSC 1000 MW, 350kV
!! Transistor (IGBT) controlled
!! Continuous Reactive Power Control
!! Easily expandable to more terminals
!! Dynamic voltage regulation
!! Black start capability
!! Extruded cables
550 MW, 120x50x11 meters
600 MW, 200x120x22 meters
What is HVDC (Classic)?
HVDC Configurations &Transmission modes
Monopolar
Bipolar
HVDC Transmission Modes
Bipolar Multiterminal
12-pulse groups
UHVDC Transmission Modes
UHVDC Bipole
12-pulse groups
12-pulse groups
12-pulse groups
12-pulse groups
Transmission
Capacity up to
appr. 7000 MW
Componentes Sistemas HVDC
Costos de
inversión
Distancia
Estaciones AC
Inversión total AC
Estaciones
convertidoras
Costo de la línea
Inversión total DC
¿Porque HVDC? Comparación de costos AC DC
Distancia crítica
Itaipu Transmission System, 2 x 6300 MW = 12600 MW
60 Hz
HVAC 6300 MW
800 kV
60 Hz
HVAC 800kV
34m
50 Hz
HVDC 6300 MW
±600kV
±600kV
60 Hz
HVDC ±600kV
34m
Examples of HVDC projects: ABB
See also: www.abb.com
NorNed HVDC Cable, Norway - Holland
Customer’s need
!! Worlds longest sub sea cable transmission
to allow optimal utilization of production
resources in two markets
Solution
!! Turnkey 700 MW system with innovative ±
450 kV converter system. Cable length 580
km.
Customer’s benefits
!! Short delivery time and high performance
Technical Data:
Commissioning year: 2002 Dec. Pole 1,
2003 June Bipole
Power rating: 3000 MW
DC voltage: ± 500 kV
Length of overhead DC
line: 890 km
Main reasons for
choosing HVDC system: Long distance, network
stability, environmental
concerns
P
3000MW ± 500kV Three Gorges HVDC Project
Baltic Cable 600 MW HVDC link
Shunt Capacitors
Harmonic Filters
Valve Hall
Converter
Transformers
AC Switchyard
Approximately 80 x 180 meters
Monopolar Converter station, 600 MW
AC line
DC Switchyard
DC line
The HVDC Classic Monopolar Converter Station
Converter station
Transmission line or cable
Converter
Smoothing reactor
DC filter
Telecommunication
Control system
AC filters Shunt
capacitors or other reactive
equipment
AC bus
~~
HVDC Technology: valves,
converter transformer & filters
Thyristor Function
"!Block high voltage in reverse
direction
"!Block high voltage in forward
direction
"!Conduct current in forward
direction at very low losses
"! Turn on when given firing pulse and positive voltage
"! Turn off when the thyristor current
crosses zero
+ Vthyr -
Current direction
Valves
Thyristor Valves: Purposes and Functions
"!Composed by various thyristor
"!Connect ac-phases to dc-
system
"! Conduct High Current
"! Block High Voltage
"! Controllable
"! Fault Tolerant and Robust
Thyristor equipped rectifier operation
Star
winding
6-pulse Graetz
rectifier bridge
To load
From
load
0
Phase Angle increased #Reduced Power
Transformador convertidor
El sistema de transformadores convertidores cumple
las siguientes funciones:
!! Aislación galvánica entre el sistema AC y DC
!! Ajusta los voltajes AC a los requeridos DC y viceversa
!! Limita la corriente de cortocircuito
!! Introduce el desface de 30 grados necesario para
configurar un puente de 12 pulsos
!! Limita y corrige los cambios de voltaje estacionarios del
lado AC
Converter transformer, configurations
Converter transformer, single-phase three-winding
Typical characteristics
for a Converter
Transformer:
-!Transport weight approximately 250 tons
-!Installed weight approximately 350 tons
Harmonic currents on the AC side of a converter
AC filters types
Series resonance filter High-pass filter Double-tuned filter
Filtros AC
HVDC Control
HVDC Control, Line-commutated converters
100 W 99 W
+99 V +100 V
1 !
Inverter Rectifier 1A
~ ~ +100 V +99 V
Power direction:
1 !
Inverter Rectifier 1A
~ -99 V -100 V
~
100 W
-100 V
99 W
-99 V
Power reversal:
HVDC Transmission Control
!! Valve Firing angle
!! Transformer Tap-changer
!! Shunt filters, capacitors & reactors
Filter
Filter
Filter
Filter
HVDC Control Overview, Valve firing angle
Rectifier Inverter
Firing angle DC current Minimum extinction
angle
Filter
Filter
Filter
Filter
HVDC Control Overview, Tap-changer
Rectifier Inverter
Firing angle DC current Minimum extinction
angle
Tap changer Steady state firing
angle
Steady state DC
voltage
Filter
Filter
Filter
Filter
HVDC Control Overview, Filter banks
filter converter
unbalance
I d
Q
Rectifier Inverter
Firing angle DC current Minimum extinction
angle
Tap changer Steady state firing
angle
Steady state DC
voltage
Filter banks Harmonic filtering Harmonic filtering
Reactive power Reactive power
Filter
Filter
HVDC reference projects
Longquan Converter Station, Panorama View
Converter Station size:
600m x 360m
Double Valves 500 kV DC, Zhengping
Potencial de aplicación en Chile
!! Proyectos de transmisión punto a punto destinados a
transportar grandes bloques de potencia por grandes
distancias
!! Explotación de recursos hídricos en extremo sur del país
!! Proyectos Aysén y Energía Austral
!! Proyectos de interconexión de sistemas con
frecuencias distintas o dinámicas incompatibles
!! Interconexión Perú-Chile
!! Interconexión SIC-SING
!! Interconexiones que requieran cable soterrado o
submarino
Muchas gracias
DC in
Electrode
Equipotential
contours
Current
paths High-resistivity
environment => high DC potentials
at e.g. converter station
Electrodes
DC in
Electrode
Equipotential
contours
Current
paths Low-resistivity
environment => low DC potentials at
e.g. converter station
Electrodes
low
resistivity
high
resistivity
low-
resistivity
rock
Anisotropy or low-resistivity structures will change the
shape of potential contours. The effect from the electrode will be different in different directions.
Electrodes