Smart distribution: A self-healing and optimized grid

By Scott Zajkowski and Kevin Mays, IUS Technologies

Smart distribution is a fully controllable and flexible distribution system with embedded intelligence from substation to meter. It enables the distribution system to be a self-healing and optimized grid. To reach smart distribution, a utility must remotely monitor, manage and control the distribution circuits in real time from the substation to the end of line. In addition, smart distribution requires intelligence throughout the distribution system. Smart sensors and monitors are key and must be deployed throughout each feeder line and work in conjunction with reclosers, automated switches, capacitor banks and voltage regulators.

Volt/VAR Optimization

Grid optimization allows utilities to leverage more value from their current distribution infrastructure, preventing additional investment and need for new generation, transmission and distribution assets. Implementing volt/VAR optimization (VVO) throughout the distribution system is paramount to optimizing the grid. To do this, remote monitoring via sensors must provide the distribution management system with real-time data from many points throughout the distribution line to the grid’s edge. These smart sensors throughout the distribution system allow utilities to control voltage and VAR for intelligent decision-making. The smart sensors record and provide real time and accurate data about distribution feeder line and equipment condition. More devices in the field reporting data make it critical for utilities to mitigate data overload at the control center by using unsolicited messaging. This data and information provide utilities with a comprehensive view of the distribution load and voltage conditions from the substation to the end of the line. Controlling VAR levels minimizes losses by working in conjunction with capacitors banks.

VVO benefits are significant. They provide enhanced reliability, efficiency and more. By optimizing the grid, utilities can minimize system losses and demand through a lower voltage profile and in turn reduce end users’ energy consumption, lowering their costs. This form of distribution automation allows electric utilities to control demand and increase distribution system efficiency. Peak demand also is alleviated through VVO, which extends the life of the infrastructure, optimizes asset utilization and reduces the need for additional investment in infrastructure. Electronic sensors play a major role in grid optimization by pinpointing trouble spots, voltage and VAR conditions, power quality issues, outages and more. Utilities no longer have to depend on customers’ calls to notify them of an outage or power quality issue, such as low voltage. Smart sensors enable utility workers to be immediately dispatched to troubled areas, significantly reducing customer outage minutes each year and increasing utilities’ revenue.

Residential, commercial and industrial end users are demanding higher reliability and power quality, and grid optimization through VVO can improve system performance and increase service quality. Smart demand management leverages current electric utility infrastructure and increases its capacity.

Volt/VAR Control

New or pending regulations for energy conservation methods are some of the main drivers of grid optimization implementation. Optimizing the grid or operating the distribution system at a lower voltage level has a significant impact on total energy reduction. Volt/VAR control (VVC) allows utilities to meet these regulations. VVC results in environmental benefits by reducing waste from early product failures and reducing greenhouse gas emissions through decreased energy losses and improved energy efficiency.

Equipment and sensors are key assets to grid optimization; however, deeper software integration is also required for utilities to more effectively and efficiently coordinate power distribution. VVO requires real-time voltage information from sensors located throughout the distribution line to allow grid operators to better anticipate problems and make fast localized decisions at the edge of the distribution system.

As smart grid technologies are added into the distribution system, utilities eventually will transition to adaptive VVC (AVVC). This next phase in VVC enables the distribution system to learn from previous conditions and anticipate system needs. AVVC will allow utilities to optimize the grid and more efficiently provide power without operator intervention.

Smart Transformers and Secondary Transformer Monitoring

Smart secondary distribution transformers and secondary distribution transformer monitoring or both also are vital to smart distribution. Secondary distribution transformer monitoring typically monitors voltage, loading and sometimes temperature. These monitors provide utilities a comprehensive view of their assets in the field. Some monitors like IUS Technologies’ TM1000 and TM2000 monitor total combustible gas along with temperature and load, enabling utilities to better maintain and utilize their transformer assets. Grid operators will increase their use of transformer monitoring because it provides many additional benefits to grid optimization. It can integrate with Volt/VAR optimization to provide additional value and justify implementation.

Secondary transformer monitoring provides utilities with outage notification, revenue protection from theft, asset management and improved power quality, providing even more value and justification for the utility.

Self-Healing Grid

With federal government support via the American Recovery and Reinvestment Act (ARRA) of 2009, many utilities invested in self-healing grid programs by purchasing new equipment such as reclosers, switch gear, automated controllers and sensors. They created a more reliable grid that is less dependent on traditional, unintelligent distribution equipment. Most, if not all of the switching and controller devices in these grids include communication technologies (integrated or modular) for notification and timely control. Remote smart sensors with integrated communications provide intelligent visibility of distribution feeders. Subsequently, the self-healing grid requires a robust IT and communications infrastructure to monitor, report and control the reconfiguration process of the distribution network.

Many of today’s electric grids are designed with multiple sources of power generation located throughout them, allowing the DA system to reconfigure and reroute power to minimize service disruptions and outages. When a fault occurs, reclosers automatically locate the fault, disconnect power at that point to isolate it and then report it. The smart distribution system uses algorithm based control commands to source electricity from an alternative power generation source and adjust loads at substations and capacitor banks, while the switchgear reroutes the power to areas around the fault location. The software intensive control centers can make decisions, precisely dispatch maintenance crews and restore power to many periphery customers in minutes, depending on the severity and size of the service area. Smart distribution systems not only allow end-users to maintain their productivity but they also allow utilities to save millions of lost revenue dollars.

Utilities will progress toward smart distribution by implementing sensors, monitoring devices and other automation equipment throughout the distribution system. Merging software and hardware will provide the benefits utilities must have to move the electric distribution grid into the future. All utilities whether cooperative, municipalities or investor-owned will face challenges in creating an optimized and self-healing grid as energy consumption increases. Additional challenges from distributed generation and electric vehicles will complicate the distribution system, requiring the implementation of intelligence to make the right decisions in real time.

Authors

Kevin Mays is an engineer at IUS Technologies. He has more than 20 years of engineering design, product development and technical sales experience. He began his career as an RF engineer at Motorola and later worked as a sales and applications engineer for Maxim Integrated Products. He has a bachelor’s of science degree in electrical engineering from Northeastern University.

Scott Zajkowski works in marketing and business strategy in IUS Technologies’ North American Business Development group. He develops end of line devices for the smart grid. He has a bachelor’s degree in packaging engineering from Michigan State University and an MBA from Indiana University Kelley School of Business.

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