Choosing the Right Meter for the Right Job

Jason Sheppard | Oct 16, 2002

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Whether updating an existing substation or constructing a new one, choosing the best meters for the job doesn’t mean you have to spend a lot of money on each one. With a full range of intelligent metering and control devices available today, it’s easier than ever to assemble a top-notch enterprise energy management network by choosing just the right meter for each job. In many cases, this means combining a single higher-end device with several entry-level meters. For example, a substation may install a single higher-end energy and power quality meter on the main incoming feed, and a smaller, inexpensive meter on each outgoing feed. If so equipped, the meter on the incoming feed could use its large onboard memory and multiple communications options to receive information from each of the smaller devices. It could then process the information and send it upstream to the company’s SCADA system, a dedicated energy management system, and any additional systems serving other utility departments. As long as each component is chosen with the specific features and flexibility to do its job, this arrangement can offer considerable advantages. For example, although the smaller meters would not need a large onboard memory, as long as each one can display real-time readings on its front panel, you can easily check operational parameters to verify that the system is working properly. This instant feedback is particularly useful when fine-tuning the substation’s electrical system, for example, when performing tap change control to adjust voltage levels. Also, if the meter on the incoming feed offers RTU/PLC abilities, it can perform additional control and alarm functions throughout the facility, to help manage any conditions requiring immediate attention. Plus, multiple communications options such as Modbus and DNP increase the flexibility of the unit, enabling it to send data to a centrally located workstation or SCADA system over the existing communications network.

With the main meter overseeing the smaller meters in the substation, you can review a month’s worth of historical data logs, right from the primary unit’s main screen. An onscreen trending feature on this device is useful for diagnosing events that have occurred in the past, and for identifying conditions that could cause problems in the future. Overall, this arrangement provides a simple and cost-effective way to monitor the whole system, providing detailed real-time and logged system information both at headquarters and right on site.

As a stand-alone meter or part of a larger system, each component in an enterprise energy management network can make a big difference in helping to maintain the reliability, power quality, and overall uptime of a substation. It’s just a matter of choosing the right tool for the job.

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Comments

Jason,

It would be helpful to put in some comparisons for cost. If you don't want to put in the actual cost numbers, you could use percentage changes. For example, look at putting four meter of the same design vs. your suggested plan of three less expsensive meters with the one expensive meter. If you have a customer that has utilized your approach, you might mention that also.

This would give the utility planner the incentive to dig deeper into your suggestion.