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High-Power Gas Tube Switches

General Electric (GE) Global Research Power & Water

High-Voltage, High-Power Gas Tube Technology for HVDC Transmission

Program: 
ARPA-E Award: 
$5,395,993
Location: 
Fairfield, CT
Project Term: 
04/30/2013 to 07/31/2017
Project Status: 
ALUMNI
Technical Categories: 
Critical Need: 

In today's increasingly electrified world, power conversion--the process of converting electricity between different currents, voltage levels, and frequencies--forms a vital link between the electronic devices we use every day and the sources of power required to run them. Power converters modify electrical energy to a usable current, voltage, and frequency for an electronic device. Today's power converters are large and inefficient because they are based on decades-old technologies and rely on expensive, bulky components. Within the next 20 years, 80% of the electricity used in the U.S. will flow through these devices, so there is a critical need to improve their size and efficiency.

Project Innovation + Advantages: 

GE is developing a new gas tube switch that could significantly improve and lower the cost of utility-scale power conversion. A switch breaks an electrical circuit by interrupting the current or diverting it from one conductor to another. To date, solid state semiconductor switches have completely replaced gas tube switches in utility-scale power converters because they have provided lower cost, higher efficiency, and greater reliability. GE is using new materials and innovative designs to develop tubes that not only operate well in high-power conversion, but also perform better and cost less than non-tube electrical switches. A single gas tube switch could replace many semiconductor switches, resulting in more cost effective high power converters.

Potential Impact: 

If successful, GE's new gas tube switches would significantly lower the system cost of very high-power electrical grid applications, transforming electric power transmission in the U.S.

Security: 

This project could contribute to a smarter, more advanced, more reliable, and more secure electric grid.

Environment: 

More efficient power converters could help reduce U.S. electricity consumption, and in turn reduce the harmful emissions created by coal-fired power plants.

Economy: 

Efficient and affordable grid-scale power converters could help lower power bills for average consumers.

Innovation Update: 

(As of March 2017) 
In 2017, GE began building appropriate controls for a gas tube switch test environment, toward the goal of full-speed “burst” operation and testing. If successful, further tube testing will be done on a circulating-power facility capable of sustained full-speed operation, prior to the construction of a larger-scale demonstrator system. GE estimates at least five years to move the technology from the lab to the grid. In the shorter term, gas tubes could be a good candidate for high-voltage protection devices on AC transmission lines. 

GE’s goal is to develop a long-life, high voltage switching gas-plasma tube capable of handling in excess of 300kV. To achieve this, the team accomplished three major tasks—the development of non-mercury liquid cathode and plasma, the scaling of device voltage, and the use of a low-loss mode of operation. The team replaced the conventional solid metal cathode with a liquid metal one because it has limited self-healing abilities and can be replenished if necessary. The team also demonstrated that the liquid metal cathode can operate at the high current density (5 A/cm2) required for grid applications. The team is constructing a 300kV device and expects to demonstrate it and estimate the upper limit of the operating voltage for the technology. Finally, they found that the tube can operate in a unique low-loss voltage mode that greatly benefits life and efficiency. 

For a detailed assessment of the GE project and impact, please click here.


Contacts
ARPA-E Program Director: 
Dr. Isik Kizilyalli
Project Contact: 
Dr. Timothy Sommerer
Partners
PPPL: Princeton Plasma Physics Laboratory
University of Wisconsin
Release Date: 
11/28/2012