Knowledge is power
Broadband-over-power-line (BPL) provider Current Group announced the deployment of home area networks for programmable thermostats and the introduction of underground fault detection over its networks — features that are designed to improve the reliability and efficiency of electrical grids.
According to a California Energy Commission report, about 40% of all electrical outages are caused by underground failures — a figure that could increase as underground cables deployed in the 1970s and early 1980s near the end of their usable life, said Brendan Herron, vice president of corporate development and strategy for Current.
Traditionally, such failures have resulted in customers losing power for at least a couple of hours, as the utility monitored complaint calls and deployed personnel to test transformers in an effort to identify the location of the fault, Herron said. By using Current’s BPL system and advanced embedded sensors, the utility can dramatically decrease outage time, he said.
“Because we’re constantly monitoring the cables with our advanced sensing, we’re able to tell when a fault occurs and know exactly which two transformers the fault occurred in,” Herron said. “The utility is able to go out and go to the exact transformers that are affected, isolate those two transformers, reverse the power in the system to avoid the faulted area and restore power to the customers served by the faulted cable. Then they can go fix the problem.”
Herron said Current’s solution is the only one of its kind in the industry, noting that transformer-level information traditionally has not been available to utilities.
“Historically, they’ve known what happens at the substation, but they haven’t known what happens to the power once it leaves the substation and goes to the house, other than by reading the meter once per month,” he said.
Another example of leveraging this distributed network intelligence is what Current calls the nation’s first real-time, utility home area network using programmable communicating thermostats. Deployed for Oncor Electric Delivery over its smart grid in Dallas, the network lets utilities remotely monitor and adjust power consumption during peak periods in an effort to avoid capacity-driven outages, Herron said.
“From a utility control center, we can actually go into a house and adjust thermostats,” he said. “So for a customer who is signed up for a demand-response program — where they allow the utility at peak times to adjust their thermostat in exchange for a lower rate — we can actually adjust the thermostat.”
Electric utilities have long had demand-response programs, but they have enjoyed limited success because the utility would turn off the compressor to the house, so customers were hesitant to register for the program, Herron said. In addition, the utilities had difficulty verifying whether the shutdowns actually helped reduce its overall load.
Current’s system is designed to address both issues by providing usage information to the utility and — more important — dialing down energy to a house instead of shutting off air conditioning completely for a period, Herron said. By remotely adjusting the thermostat at several locations, utilities can avoid many outages.
“It’s a lot better to change the thermostat a couple of degrees on a lot of people than to have a brownout or blackout,” Herron said.
And power shortages during peak periods are expected to be a growing problem, as the consumer electronics boom has helped fuel a 16% annual increase in power demand at a time when environmental concerns are preventing the construction of new power plants, Herron said. The thermostat-adjustment capability also can help utilities make better economic decisions, he said.
“Rather than go out and having to buy very, very expensive power [during peak periods], they can give their consumers some benefit and adjust down the amount of power they’re using,” Herron said.
CURRENT DEPLOYS SMART GRID IN DALLAS
Services include:
- Smart metering — more than 1.8 million meters in Dallas, Fort Worth, Waco and some other areas.
- Detection of deterioration and overload for more than 400,000 transformers.
- Outage detection and restoration.
- Substation connectivity.
- Exclusive right to operate network to sell retail communications services.
Present status:
- More than 120,000 homes passed by the end of 2007.
- Public Utility Commission of Texas rule-making in May 2007 defined requirements for an advance meter surcharge.
- Oncor Electric is converting to 100% remote connect/disconnect meters starting in 2008.
