Premisas, objetivos, estrategia y restricciones

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 Convertidora AC<=>CC Trasmisión en CC Convertidora CC<=>AC Sistema AC 2 Transmisión expresa de potencia eléctrica sobre una distancia de ~700 a 2300km

HVDC 2 Technologies 1.- HVDC Classic 7000 MW, 800kV 600 MW, 200x120x22 meters Thyristor controlled Switched Reactive Power Control Typical design valve building plus switchyard Mass impregnated cables 2.- HVDC VSC 1000 MW, 350kV 550 MW, 120x50x11 meters Transistor (IGBT) controlled Continuous Reactive Power Control Easily expandable to more terminals Dynamic voltage regulation Black start capability Extruded cables What is HVDC (Classic)?

HVDC Configurations &Transmission modes Monopolar Bipolar HVDC Transmission Modes Bipolar Multiterminal 12-pulse groups

UHVDC Transmission Modes UHVDC Bipole Transmission Capacity up to appr. 7000 MW 12-pulse groups 12-pulse groups 12-pulse groups 12-pulse groups Componentes Sistemas HVDC

Porque HVDC? Comparación de costos AC DC Costos de inversión Inversión total AC Inversión total DC Costo de la línea Estaciones convertidoras Estaciones AC Distancia crítica Distancia Itaipu Transmission System, 2 x 6300 MW = 12600 MW HVAC 6300 MW HVAC 800kV 800 kv 34m 60 Hz 60 Hz HVDC 6300 MW ±600kV HVDC ±600kV ±600kV 34m 50 Hz 60 Hz

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

3000MW ± 500kV Three Gorges HVDC Project Technical Data: Commissioning year: 2002 Dec. Pole 1, 2003 June Bipole Power rating: DC voltage: Length of overhead DC line: Main reasons for choosing HVDC system: 3000 MW ± 500 kv 890 km Long distance, network stability, environmental concerns Baltic Cable 600 MW HVDC link

Monopolar Converter station, 600 MW AC line AC Switchyard Converter Transformers Valve Hall Shunt Capacitors DC line Harmonic s Approximately 80 x 180 meters DC Switchyard The HVDC Classic Monopolar Converter Station Converter station Converter Smoothing reactor Transmission line or cable AC bus DC filter Shunt capacitors or other reactive equipment AC filters Telecommunication ~~ Control system

HVDC Technology: valves, converter transformer & filters Thyristor Function + Vthyr - Current direction 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

Valves Thyristor Valves: Purposes and Functions Composed by various thyristor Connect ac-phases to dcsystem Conduct High Current Block High Voltage Controllable Fault Tolerant and Robust

Thyristor equipped rectifier operation Phase Angle increased Reduced Power To load 0 Star winding 6-pulse Graetz rectifier bridge From load 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 Power direction: Power reversal: ~ 1 +100 V +99 V 1A Rectifier Inverter ~ ~ 1-99 V -100 V 1A Inverter Rectifier ~ +100 V +99 V 100 W 99 W 99 W -99 V -100 V 100 W

HVDC Transmission Control Valve Firing angle Transformer Tap-changer Shunt filters, capacitors & reactors HVDC Control Overview, Valve firing angle Rectifier Inverter Firing angle DC current Minimum extinction angle

HVDC Control Overview, Tap-changer Rectifier Inverter Firing angle DC current Minimum extinction angle Tap changer Steady state firing angle Steady state DC voltage HVDC Control Overview, banks Q filter converter unbalance I d Rectifier Inverter Firing angle DC current Minimum extinction angle Tap changer Steady state firing angle Steady state DC voltage banks Harmonic filtering Harmonic filtering Reactive power Reactive power

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

Electrodes DC in Electrode Current paths High-resistivity environment => high DC potentials at e.g. converter station Equipotential contours Electrodes DC in Electrode Current paths Equipotential contours Low-resistivity environment => low DC potentials at e.g. converter station

Electrodes low resistivity high resistivity lowresistivity rock Anisotropy or low-resistivity structures will change the shape of potential contours. The effect from the electrode will be different in different directions.