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