Public/private initiative moves smart grid adoption
Ontario’s PowerStream builds communications infrastructure
Published In: Intelligent Utility Magazine November/December 2011
REPERCUSSIONS OF THE INFAMOUS BLACKOUT OF AUG. 14, 2003, that impacted northeastern North America were swift and wide-ranging, affecting more than 10 million people in Ontario, who were among those left without power for extended periods of time. The outage put into motion a series of events that would subsequently reshape the province's electrical power infrastructure and customer engagement.
Ontario was a net energy importer at the time and the debilitating outage spurred government officials into action to prevent a recurrence. A major program initiated in 2004 would balance added capacity (including renewable sources) with ambitious public efficiency and conservation programs.
Upgrades to the electrical grid included advanced metering infrastructure (AMI) intended to engage residential and commercial customers in managing their power consumption, in part because of impending government-mandated dynamic pricing.
PowerStream, the second largest municipally owned electricity distribution company in Ontario, was one of 13 electric distribution utilities out of the 80 in the province directed by the provincial government to be early enablers. These 13 utilities represented about 75 percent of the province's customer base.
One-way vs. two-way
All utilities in the province are regulated by the Ontario Energy Board (OEB) under the Ontario Energy Board Act of 1998. PowerStream's more than 330,000 customers are located in a relatively high-density service territory covering more than 309 square miles (or 800 square kilometers) in communities located immediately north of Toronto and in Central Ontario.
PowerStream worked jointly with six other large distributors and the provincial government on the crucial phase of establishing minimum specifications for AMI functionality. There was intensive lobbying of the government to adopt a one-way communications standard for the minimum specification, but PowerStream felt obtaining the requirement for two-way broadcasting was essential to support future expansion and applications.
Once the minimum specification was completed, five AMI vendors and five installation contractors were approved to participate in the program and the utilities could select from this group.
Licensed spectrum essential
PowerStream piloted three different technologies in 2006 with two mesh networks and one fixed RF system based on licensed wireless spectrum. Full-scale wireless meter deployment began in 2007 and was completed in 2011 after the installation of 314,000 residential and small commercial meters. Large C&I customers were exempt from the AMI rollout.
It was clear that fixed radio frequency (RF) technology would be very suitable and successful. RF was relatively inexpensive to deploy and its structural characteristics were well suited to the local topography and density. Licensed 900 MHz frequency from the AMI vendor chosen was deemed essential because the utility wanted the high broadcasting power, which results in a high success rate when polling meters.
The province requires a 98 percent daily success rate when polling meters, which may seem high. But if you have 2,500 customers in a billing cycle and you don't achieve at least that success rate, it means 40 to 50 customers aren't billed based on the system's interrogation and those have to be handled manually. The high strength of the licensed signal results in a higher success rate; actually closer to 99.5 percent.
There have been cases in the province where public spectrum was interfering with cell phones, garage door openers, baby monitors and other devices. Licensed spectrum largely eliminates this interference. Unlicensed spectrum is regulated by the province to transmit at a much lower power broadcast signal, so success rates at polling are lower. As well, while another user can't be forced out of the public spectrum if there is any encroachment or "non-complimentary usage" in licensed frequency, the frequency owner can force them out.
Licensed spectrum can also support water and gas metering, which would enable PowerStream to potentially support those services at some point in the future.
Towers with mesh collectors
The physical installation of meters was not an issue, as the system chosen by PowerStream was largely plug-and-play, resulting in savings across the board. There are about 15,000 to 20,000 customers per tower, as compared with a mesh network that would have required numerous collectors. Geographic density lowered the physical costs of deployment, as individual installers working for the contractor were able to make 65-70 meter switchouts a day.
In regulatory hearings PowerStream has stated that it will have one of the lowest-cost installed endpoints in the province with superior functionality.
This was essential for PowerStream's and its shareholders' interests to mitigate the risk of cost recovery. A winning solution had to be cost effective.
The promise of the operational data stream
While the Ontario government's conservation program was targeted at billing and time-of-use (TOU) rates, PowerStream was equally interested in what could be done with the operational data coming from the meters.
The licensed spectrum (managed by Industry Canada) has considerable value. Signal strength is greater, enabling the development of numerous applications.
The ability to detect outages quickly is a significant advantage with the smart meters providing valuable supplemental information to the Outage Management System (OMS). An interface between the AMI, OMS and GIS systems was built and implemented almost three years ago, providing the equivalent of a low-end SCADA functionality.
The interface among the three systems is real time. The AMI working with the OMS lets technicians locate the outages quickly and accurately, enabling us to determine if the affected service is underground or overhead.
Operators use data from smart meters to effectively manage their dispatch because fault location is so precise. In years past, crews dispatched at night would use flashlights to detect breaks in the conductor. Now, the system is able to indicate which homes are affected and in some cases to identify if the problem is with the resident's electrical system.
Immediate and future value
There's no question that having a 21st century AMI system in place is producing some immediate benefits for both PowerStream and its customers. The high-power signal from the licensed wireless network ensures more accurate polling and it allows much better, targeted maintenance. Savings from reduced truck rolls for outages that actually result from a problem on the customers' own electrical service alone are estimated to be upward of $150,000 annually.
The AMI network functionality enables the utility to enhance reliability and improve its service delivery. One case had a crew performing regular maintenance around the corner from a group of houses that were suddenly without service. A dispatcher immediately saw the problem and instructed them to check out the transformer. An affected PowerStream customer calling to report that outage was still on the phone when he looked out of his window and saw the crew already at work.
Asset optimization and life management is another benefit of having the licensed spectrum network. PowerStream is in the early stages of installing smart meters in the pad- and pole-mounted transformers scattered throughout its service territory.
The rationale for this effort is straightforward. First, the smart meter has the ability to measure current and differentiates between the three phases. Second, if the bulk of communications about asset life, outages, faults, transients and excessive voltage conditions comes from the transformers instead of the endpoints, this can radically decrease communications traffic to decease the latency. Doing so can reduce the number of RF signals by approximately 90 percent to help conserve bandwidth.
PowerStream reasons that improved transformer monitoring can maximize asset life by avoiding the overloading conditions that shorten their life. Although the associated savings are difficult to quantify, this initiative has great promise.
PowerStream is confident that the technology strategies adopted were correct and in line with Ontario's goals for energy supply security and conservation. Today there's certainty that the risk of repeating the experience of August 2003 is much reduced.