Massachusetts Electric and Nantucket Electric d/b/a National Grid on June 28 filed with the Massachusetts Department of Public Utilities the Smart Energy Solutions Pilot Final Grid Evaluation Report, which the company said provides an evaluation of the two years of distribution grid-side results from its Smart Energy Solutions Pilot in Worcester, Mass.
As noted in the report, the pilot integrates customer-facing and grid-facing technologies and solutions to understand the value of an end-to-end smart grid solution, and to conduct experiments on new and innovative equipment to better understand its value for use in the future.
In the pilot, the company has installed and is operating advanced grid-side technology in order to study the ability of the technology to improve service reliability, operational efficiency, and thermal performance. The company added that it is also studying the ability of the technology to enable faster outage identification and system reconfiguration with a goal of reducing, and in certain situations eliminating, power interruptions.
Furthermore, the company said that it has installed and is operating a multi-tiered communication system that, in combination with distribution system devices, can enable crews to be dispatched to damage locations with greater accuracy and restore power in a shorter time period. The new equipment can identify which customers or areas are affected during storms or emergency conditions, thereby improving restoration times, the company said.
The technologies were deployed on about 150 miles of electricity distribution lines in Worcester and four local substations (Bloomingdale, Cooks Pond, Greendale, and Vernon Hill), the company said, noting that the pilot area includes a mix of urban and suburban-type areas, with overhead and underground electric distribution systems. The company said that the technology installed on the overhead and underground electric system within the pilot area included:
- More than 180 distribution automation devices on 10 13.8-kV feeders
- Four substations outfitted with multiple types of automation
- Advanced distribution automation (ADA) technology, which consists of sectionalizing protection equipment that is automated and controlled in a coordinated manner to minimize the effects of outages
- Advanced capacitor controls (ACC) technology, which involves coordinated control to reduce losses, reduce peak and average demand, and improve power factor and voltage performance
- Advanced monitoring of feeder, transformer, distributed generation (DG), and electric vehicle (EV) charging sites
Specifically, distribution feeders that provide electricity to customers in the pilot area were upgraded to include advanced sensors, grid operation and control equipment that use a two-way communication system, the company said. All of the technologies installed on the distribution grid communicate with the company’s existing energy management system in its distribution operating center, the company said.
The company said that key findings from the grid-facing evaluation include:
- Service reliability – ADA delivered a reduction of 194,000 customer minutes interrupted (CMI) over the two-year pilot; System Average Interruption Duration Index (SAIDI) for the pilot area experienced a 10% reduction with ADA
- Operational efficiency – Significant reduction in manual field switching activities for planned work; more efficient deployment of resources to damage locations; equipment with device settings no longer required field visits to make changes or adjustments; improved engineering analysis and customer complaint analysis for voltage or loading issues
- Thermal performance – Six of the nine feeders demonstrated peak daily load power factor improvements
The company noted that it performed experiments and analysis of specific technologies to understand the opportunity that those solutions could provide to the grid. For instance, the company said, the single-phase capacitor switching experiment resulted in successful independent phase load balancing.
The purpose of that experiment was to analyze the effectiveness of single-phase switching performed by the capacitor banks installed on Feeders 8W1 and 24W3, which are primarily residential, the company said, noting that traditional three-phase capacitor banks were also evaluated to form comparisons with the single-phase capacitors for switching performance. Then, both single-phase and traditional three-phase capacitors were compared to each other for power quality based on phase angle, the company said.
The company said that key learnings from the grid-facing portions of the pilot include:
- The importance of ensuring the communications network required to support grid devices is installed, tested, and enabled to provide for an efficient deployment and commissioning of distribution automation
- The need for a broader set of employee roles and capabilities than exists in the current utility workforce, in order to deliver and manage these new and enhanced equipment and technologies
- Supporting a hybrid grid communications strategy where a combination of WiMax, cellular, 900Mhz and other solutions can coexist to provide options for connecting to devices when circumstances require it
- Recognizing the complexities involved with enabling underground devices
- The need to establish an independent data analytics solution and information repository for the engineering data required to support project evaluation and perform advanced engineering analysis
Among other things, the company noted that under the program, it is also monitoring DG resources and EV charging stations at select locations in Worcester to better understand the behavior of those specific solutions and how they may impact the distribution grid when expanded on a larger scale. That, the company said, includes solar and wind DG locations within the pilot area to help the company study the impact of DG on the electric system and considerations for future integration.
Discussing EV integration, for instance, the company said that all of the EV charging stations that it monitored resided behind the meter. The profile of usage shows that the stations were used fairly consistently during the weekday, the company said, adding, “When looking at the time of day, it became apparent that over 70% of the usage being drawn from the stations occurred between 5AM and 12PM.”
Noting that it does not maintain customer data regarding residential installed EV charging, the company said that while the current load profiles for the charging stations reviewed do not present an immediate transformer load concern, if the quantity of charging stations were to be expanded, then the current load and usage profiles are extremely valuable information for not only transformer loading, but also overall feeder loading considerations.”
Since much of the usage for public stations occurs within the peak usage period of Monday through Friday between 8 a.m., and 8 p.m., there are also considerations around possible time of use energy costs, especially during peak events, and the pricing impacts, as well as possible demand response considerations, the company said.