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Is There a Gold Standard for Electric Distribution Grids?

April 19, 2018
Is it possible that someday ADMS’ will become mandatory for utilities?

A number of utilities around the country and internationally might argue that the “gold standard” in the electric distribution world is an advanced distribution management system (ADMS).  They installed these systems, customized to meet their specific circumstances, in response to unsatisfactory system performance during a major disturbance or growing system complexity that demanded faster or more finely tuned system control.  Is it possible that someday ADMS’ will become mandatory for utilities?

Last year electric utilities experienced a number of major hurricanes and other disruptive events, including extensive wildfires.  We even heard uncommon terms related to storm events such as derechos (straight-line, severe-wind events) and bomb cyclones (low pressure events often associated with strong storms). And in 2018, Mother Nature has been unrelenting with storm after storm.  On the back side of such events, we hear stories of marked outage restoration improvements compared to the past due to distribution automation upgrades.

Distribution automation (DA) uses digital sensors and switches with advanced control and communication technologies to automate functions on a distribution system.  The “gold standard” of DA may be an ADMS, a software platform that integrates a portfolio of automation functions for optimization of distribution grid performance and maintenance.  Automated fault location, isolation, and service restoration; conservation voltage reduction; peak demand management; and volt/volt-ampere reactive (volt/VAR) optimization are frequent DA functions incorporated into an ADMS. A number of companies offer ADMS’ including ABB, Advanced Control Systems, Oracle, GE, OSI, Survalent Technology, Schneider Electric and Siemens. 

CenterPoint's System: Storm Response

CenterPoint Energy, serving the greater Houston area, sees 20 to 30 large storm events every year.   According to Kenny Mercado, senior VP of electric operations, CenterPoint developed a highly proactive storm preparedness program that includes an advanced metering system, ADMS, an intelligent grid, a mobile data platform, a power alert service system and automated customer service functions.  CenterPoint’s ADMS system recognizes faults on the system, sectionalizes feeder circuits through intelligent grid IT sensors and helps route crews efficiently when there is a disruption.  The DSCADA system allows CenterPoint dispatchers to communicate with 2,000 intelligent grid switching devices and other automated switching devices on the system.  The back office system can communicate in real time to those devices and recover power more quickly by automatically restoring service under some conditions and minimizing the extent of any disruption requiring a truck-roll.

Arizona Public Service: Solar Influx

Companies embark on the journey to implement an ADMS for various reasons.  For APS, a major consideration was the rapid increase of solar resources on its system, but like many companies that pursue an ADMS, other factors helped the case, including the need for technology upgrades, better asset utilization, and improved system response and performance.   The company’s system solution included an energy management system (transmission); ADMS; Advanced Meter Infrastructure (AMI); Communications Infrastructure; and Advanced Analytics. APS refers to its system solution as a flexible grid that delivers needed visualization and automation. 

Regulated Reliability

In Finland, regulators adopted the Electricity Market Act of 2013. The law dictates that outages may not last longer than six hours in urban areas, or 36 hours in rural areas. By 2028, distribution system operators must be able to ensure that the length of any interruption in their network will be within these limits. Elenia, a major distribution company in Finland, has turned to an ADMS offered by ABB to help it meet the new requirements.  Will ADMS’ become essentially mandatory here in the United States as well?

Not necessarily.  Many utilities have implemented programs that addressed their reliability and resiliency needs without implementing a full-blown ADMS.  NV Energy operates and maintains a combination of modern and older electric system components that serve nearly 90% of Nevada’s population.  In order to increase situational awareness on its system, NV Energy instituted a remote line sensor program to obtain real time operating data for use in load balancing, resolving power quality issues and restoring service.  It includes a grid monitoring platform utilizing inductively powered sensors and a software package with predictive system analytics.  According to Ron Kirker with NV Energy, the software can send notifications to crews, which in turn allows them to improve service reliability.  Crews get notices regarding possible power quality issues, potential equipment failures, network overloads, momentary outages and line disturbance conditions.

Another Approach

Eversource Energy has another approach to improving reliability and resiliency. Timothy Callahan with Eversource prepared an article for T&D World  describing the company’s use of single-pole disconnect devices and fault interrupting Fusesavers.  The Fusesaver is an electronically controlled, self-powered device that can detect, open and clear a fault in a half-cycle, saving the fuse and avoiding an outage in the case of a temporary overcurrent situation. Eversource installed the devices on a number of single and three-phase distribution circuits.  

Central Georgia Electric Membership Corp. (CGEMC) graduated to addressing its reliability needs with the installation of a fault location, isolation and service restoration (FLISR) package. Prior to implementing a full DA tool, CGEMC had implemented a power factor correction solution on its distribution feeders and tied it into a central SCADA system using cellular communications. The next step was to tie its SCADA and communication system to pole mounted reclosers reflecting a new sectionalizing scheme developed for the DA system. CGEMC selected a centralized automation control scheme using Survalent Technology’s fault location, isolation and service restoration package.  According to Herschel Walker, VP of engineering services at CGEMC, the new system met or exceeded the utility’s SAIDI, SAIFI and CAIDI goals.

Numerous utilities throughout the country have demonstrated there are many ways to increase reliability and resiliency, reduce distribution system losses, and improve customer service without an entire makeover of their system.  Some companies have sufficient justification to implement an extensive ADMS.  It is hard to say there is a gold standard for electric distribution that is appropriate for everyone. Our talented distribution system managers, planners, engineers and operators appear to be making the right calls.

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