Using SCADA for Peak Demand Savings, Better Load Management, Faster Dispatch & Outage Response

By Susan Ryba

This article appears in the October 2013 issue of Public Power magazine.

To replace an obsolete, thirteen-year old hardware platform and take advantage of emerging technologies, North Carolina’s Greenville Utilities Commission conducted a wide review of today’s SCADA landscape. Priorities for the purchasing decision included reliability, scalability, ability to exchange enterprise data, security, costs, ease of maintenance, cut-over/commissioning procedures and the installation process. The evaluation involved stakeholders from across the organization and the development of a report card of features the utility could measure and grade. Upon compiling the data, a SCADA system from Survalent Technology came out on top.

The Greenville Utilities Commission (GUC) provides electric, water, sewer and natural gas services to the City of Greenville and 75% of Pitt County, serving a combined total of more than 135,800 customers.

Affiliated with Hometown Connections, Survalent Technology is the oldest and most experienced independent supplier of SCADA systems for electric, transit, renewable and water/wastewater utilities in North America. For over 50 years, Survalent has helped more than 400 utilities use operational data to increase reliability, efficiency and customer service.

“Because we were converting from a Survalent VMS system, the cutover process and internal costs associated with it offered a much better proposition than selecting a new vendor,” said John L. Powell, P.E., Substation and Control Systems Engineering Coordinator.  “Additionally, the graphics and database conversion from our old system were handled by Survalent.  One of the most important aspects was the ability to interface with our existing load management system.  Survalent was able to demonstrate that they had already accomplished this in the past for other utilities, giving us an increased level of comfort in selecting them as our vendor.”

According to Powell, the primary improvement of its new SCADA system is the quality of the interface for configuration and programming. Setting up new sites and communications is much easier with the new system. Also, due to the hardware upgrade, the responses to control commands are much quicker.  In the near future, GUC will use the new Survalent system to monitor networking infrastructure such as radios and Ethernet switches and will integrate SCADA with the outage management system.

“I believe customer support is an area that cannot be overlooked when assessing the value of a particular system,” Powell said. “In my opinion, Survalent’s customer support is a real asset.  They are responsive when called, and go the extra mile to keep customers satisfied.  We also participated in training classes that they provided on site, prior to the new system going live. The training that they provide is comprehensive and tailored to the audience.”

Rockwood Electric Utility (REU) serves over 14,500 electric customers in Tennessee. For REU, a priority when selecting a new SCADA system was the ability to engage in Dynamic Voltage Reduction (DVR) during peak demand to reduce wholesale power costs. DVR enables utilities to shave the peak of their power demand curves by reducing the voltage across their distribution system.

 “Along with DVR, we wanted to control our load tap changers at the substations and voltage regulators out on the distribution lines,” said General Manager Kendall Bear, P.E.  “We also wanted to be able to monitor load at different points on our system and be in a position to trip and close breakers and reclosers without having to dispatch crews to these devices.  We felt this would improve our reliability and give us the ability to restore power to our customers more quickly.  Operationally, with our new system from Survalent, we can remotely apply a hot-line tag, ground trip block, or non-reclose (i.e., “A”-switch), which eliminates the need to dispatch personnel and equipment to automated controls in the field.  Dispatching and operating from a central location in the office has been helpful as well.”

In addition, REU wanted to use notification features such as text messaging when a breaker or other device is operated.  This early notification helps identify the extent of an outage before checking phone messages, with the utility able to dispatch a crew directly to the affected circuit to start patrolling the line.

“Before making our purchasing decision, we talked to several utilities in the Tennessee Valley that use Survalent and received positive feedback,” Bear explained.  “We visited at least two of the utilities and talked to others who had gone through the bid or evaluation process. Survalent was consistently being selected or at the top of the list.”

Today, Survalent’s MultiSpeak interface is enabling REU to bring voltage readings back from the AMI system, helping the utility monitor voltage at various points.  “We have also been able to improve our overall power factor during peak and off-peak times by modifying the settings on capacitor banks,” Bear added. “We are able to monitor and record reactive power at the feeder and system levels via SCADA.  Capacitor banks can be accessed remotely from the office via our 900 MHz radio system and operated manually, or their settings can be modified for different times and seasons to optimize their operation.”

Susan Ryba is a marketing consultant for Hometown Connections.

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