More-Reliable Power Grids

Combining nanotechnology with wireless sensor networks could provide a cost-effective solution to widespread power failures.

The power grid is, for the most part, built on antiquated technology. When transformers and other equipment are installed, they are expected to work for about 40 years, replaced only when they fail. Additionally, components of the grid--from substations, to transformers, to circuit breakers in homes--can't signal to the local utility companies when damaged. This makes some power failures a surprise, and it protracts the fixing process, as utility workers need to physically identify the place where equipment is damaged.

To try to make a better grid, researchers at the University at Buffalo (UB), in New York, are investigating ways to retrofit the present-day infrastructure with some new technology and communication systems. They suspect that the recent advances in nano-sensor technology and wireless networks could be key to providing an inexpensive and efficient way to monitor grid health and help repair damage more quickly.

The idea is to disperse sensors with integrated processors and wireless capabilities throughout the grid, says W. James Sarjeant, chair of the electrical-engineering department at UB. The chip would be about the size of a pinhead, he says. The tiny devices wouldn't need to be built into the equipment, he adds, but would simply be placed near it so that they could pick up electromagnetic signals. As the sensors collect information, the onboard processor would churn through the data, and transceivers would send and receive data to and from other sensor nodes, or a central station.

Sarjeant and his interdisciplinary team are considering building their nano sensors out of conventional semiconductor material such as silicon, gallium arsenide, or gallium nitride. This way, says Jonathan Bird, professor of electrical engineering at UB, the sensors would be compatible with existing micro-fabrication technology. Also, he says, various types of sensors could be fabricated on the same chip.

In particular, the researchers suspect that a class of sensors called "quantum point contacts" could be a potential candidate for their system. They've shown that quantum point contacts can be used as compact nano-scale circuits that filter out particular electrical frequencies. This function could be useful because power equipment sometimes emits subtle yet distinctive electromagnetic signatures prior to breaking. The researchers are currently testing if their nano-scale circuits can effectively filter out the junk signals to help detect the signatures that precede the breakdown of insulating materials in grid components.

Another type of sensor that the researchers are exploring is called a nano hall-effect transducer. This device could sensitively detect variations in the magnetic fields generated by the system. When electric current runs through a power line, a magnetic field proportional to that current is produced near the line. If the sensor detects fluctuations in the magnetic field near a power line, this could indicate a problem.