Since the mid 1980s, employees at the Florida Power & Light Co. (FPL) had been using portable, temporary power quality meters to help customers identify problems in their facilities. These meters cost thousands of dollars and measured disturbances lasting less than 0.001 sec. Typically, these meters were connected to customers' power systems after problems occurred, and they remained connected for a few days or a week while engineers hoped for a repeat performance. By this time, finger pointing had already begun between the customer, vendors, and utility. Fortunately, times were changing. In 1998, FPL managers launched a project to provide customers with ongoing PQ monitoring and reporting. Read on to find out how “smart meters” have benefited its customers.
The project's team members went looking for a new meter technology to replace an aging fleet of 4,000 solid-state data recorders (SSDRs), which were installed in large commercial and industrial facilities in the mid 1980s (see Fig. 1). These facilities would become the target customers for the utility's new monitoring service. The smart meters would inform customers of power quality events in near real time and automatically send trouble calls to FPL.
Finding such meters, however, wasn't an easy task. For starters, there were no meters available that could report outages without power flowing to the meters. Other obstacles included getting telephone lines to the meters, troubleshooting telephone line problems, and managing costs associated with dedicated lines.
Despite the hurdles, FPL engineers developed specifications and submitted a request for proposal to five potential suppliers. These suppliers offered utility-grade electronic meters or stand-alone power quality devices. In addition, FPL engineers reviewed and tested wireless technologies that would be more cost-effective and reliable than conventional telephone lines. In the end, the project team members decided that:
- Siemens S4 smart meters would provide utility metering functions (see Fig. 2, on page 10).
- SmartSynch would build wireless communications boards and incorporate them underneath the glass of the S4 meters.
- Skytel (through SmartSynch) would provide wireless communications to more than 80% of FPL's existing SSDR locations.
- SmartSynch would provide their M32 master station to collect and process the metering data.
How They Work
Smart meters go beyond the basic functions of measuring demand and consumption information for billing purposes. They are designed to report basic power quality events such as outages, sags, momentary interruptions, high and low voltages, and voltage imbalances (see the table). In addition, they allow queries in near real time (to identify current electrical conditions) and for an archived file of events.
Fig. 3 illustrates how a smart meter system operates. The meter initiates a call to the master station when power problems occur outside the limits preset by FPL and the customer. The master station receives the information, processes it, and initiates a number of possible actions.
It may generate messages to be sent to specified utility and customer personnel. These messages are sent via alphanumeric pagers, cell phones, or e-mails, and they can relay voltages (A-, B-, and C-phase); explanatory phrases (power outage, low voltage, power restored, etc.); and other useful information. It also may send files/links to FPL's trouble call management system (TCMS), which automatically generates a trouble ticket for the customer.
With the TCMS, FPL personnel receive notification about a customer's problem — without the customer calling in and placing a service request. Trouble tickets generated by the TCMS are worked at the same priority level as if the customers had personally placed the calls. Here's how trouble tickets work:
FPL care center representatives input information from the tickets into the system's computer. The TCMS then groups the input tickets by customer location and automatically narrows down the possible affected devices on FPL's system, such as a transformer, fuse, or breaker. Once the TCMS pinpoints the affected area, FPL personnel head directly to the site.
In the past, large commercial and industrial customers would often call their FPL managers right after a problem occurred. Initially, though, the customer probably knew more than the FPL manager. It would take several phone calls for a clear picture to emerge, but even then, the customer still had a problem.
Cases in Point
The majority of FPL's commercial and industrial accounts are candidates for smart meters, and the service can be expanded to include smaller businesses. The following two examples show the difference smart meters can make in real-world applications.
In one case, a facilities manager for a large manufacturing customer was away on company business. His colleagues back at the plant telephoned him to report an equipment problem. They believed the problem stemmed from low voltage provided by FPL. The facilities manager promptly contacted his account manager at FPL, who also was traveling. The FPL manager called the office and had an e-mail sent to the customer's meter to query the voltages. A minute later, he received a response from the meter showing the voltage at the site was balanced and at 100% of nominal. He relayed that information back to the customer. This was accomplished in real time without anyone having to visit the site and investigate. The customer was informed in minutes, allowing him to pursue other possibilities.
In another instance, an elementary school lost a phase at 4 a.m. when an overhead line serving the school blew a fuse during a thunderstorm. The smart meter responded and issued a trouble ticket to the utility's TCMS. FPL dispatched a crew shortly after, and the problem was corrected before school began. Without the smart meter, the problem would have gone unnoticed until someone arrived at the school. More likely than not, staff members and students would have been forced to deal with the inconveniences of a downed power system until the problem was corrected.
Smart meters with power quality monitoring and notification capabilities are valuable tools for utilities and customers. While these meters may not detect 1-cycle disturbances, they still respond to nearly all the events that affect customers on a daily basis.
Smart meters benefit utility companies by providing the information technicians need to better analyze power-system events. They also provide utility personnel with real-time data on what is actually happening at customer sites. This means utilities can collect the billing data required for the latest time-of-day rate structures. In addition, smart meters verify customer-side problems (when customers are unsure of internal or external causes) and help minimize wasted trips by utility personnel.
Finally, smart meters help meet customers' increasingly demanding needs. They monitor and report power quality data as the customer sees it, not just as the utility sees it. This makes the system a win-win solution for all involved.
Ed Brill is the power quality business manager for Florida Power & Light in Juno Beach, Fla. You can reach him at [email protected].