NREL, Sacramento Work Together on Interconnection Course of Enhancements


Killian McKenna

Every day, utilities throughout the nation obtain purposes from prospects requesting to attach their rooftop solar techniques to the grid – as much as lots of per day and 1000’s per week. This excessive quantity of interconnection requests exhibits no indicators of slowing down as the worth of photovoltaic (PV) techniques lower and states and native governments set increased renewable energy objectives for his or her communities.

This swell in solar interconnection requests has created a brand new problem for utilities as a result of every software acquired requires a technical analysis to evaluate the potential grid impacts of the brand new solar set up. This technical evaluation evaluates impacts to power high quality and infrastructure belongings and is a key component of a utility’s interconnection approval course of. Right now, utilities are evaluating interconnection purposes manually, which implies there may be an rising demand on already burdened distribution engineers.

To handle the rising quantity of requests, utilities are more and more turning to internet hosting capability evaluation to offer public visibility into the capability of their networks to accommodate solar. The ensuing internet hosting capability maps present a broad snapshot for patrons to know if their native grid can accommodate—or host—new solar technology. These maps, though helpful for high-level planning, nonetheless don’t reply the query of whether or not particular person solar purposes can interconnect to the grid, as each interconnection can set off distinctive native distribution system constraints.

Grid researchers on the National Renewable Energy Laboratory (NREL) have partnered with the Sacramento Municipal Utility District (SMUD) to resolve that ache level within the interconnection course of.

“Our project team set out to understand how a utility can assess solar applications in a fast, robust fashion while still being technically thorough,” says Killian McKenna, a senior researcher in NREL’s Grid Planning and Analysis Center and the principal investigator on the hassle.

Their resolution was PRECISE – PREconfiguring and Controlling Inverter SEt-points – a instrument that performs quick and automatic interconnection assessments and seamlessly integrates with SMUD’s present enterprise interconnection workflow.

“PV interconnection evaluation is becoming a time-consuming process as each proposed solar power system must be individually reviewed in detail to make sure it works safely with our grid,” states Sheikh Hassan, a principal distribution engineer at SMUD. “PRECISE significantly reduces this evaluation time by instantly determining optimal inverter settings for a given location.”

PRECISE went stay at SMUD on Feb. 26, 2022, and has processed over 1,700 purposes in its first six months of operation, a median of 13 purposes every enterprise day and as many as practically 30 purposes in someday. The instrument itself can scale to course of any variety of purposes; by way of automation, information integration, and quick computing strategies, PRECISE can simply deal with lots of of purposes each day.

“This is a tremendous result for our team and has ensured staff gets the help they need while speeding up the interconnection process and lowering costs for our customers,” feedback Sruthi Nadimpalli, an data expertise (IT) mission supervisor with SMUD. This performance gained PRECISE an R&D 100 Award in 2019, has helped prospects safely and effectively set up extra solar energy in SMUD’s service areas, and has worldwide potential.

Automating this workflow is difficult. To be technically rigorous, PRECISE automates the modeling of all of SMUD’s 40,000-plus distribution secondaries – or the low-voltage distribution system linked to homes and rooftop solar – and pulls in superior metering infrastructure (AMI) information as required. The instrument additionally makes use of native irradiance measurements throughout SMUD’s service space and creates mathematical fashions of every incoming PV system. This includes modeling each element of the solar panels and their orientations, in addition to the inverters and sensible inverter capabilities, to make the evaluation.

The complete course of is automated to make sure that PRECISE pulls in information as quickly as a buyer’s interconnection software is created and updates enterprise groups downstream (i.e., planning, metering, line design) as soon as its calculations are full, making a streamlined solar interconnection course of tailor-made to suit SMUD’s distinctive native wants.

One frequent situation for SMUD prospects includes requests to interconnect solar power techniques bigger than the grid may accommodate in a selected location. PRECISE automates an evaluation of what dimension system the grid can accommodate and the way superior inverter capabilities can help approval. In these situations, planning engineers have this data and may work with the client to discover a resolution to allow the PV system to interconnect efficiently.

For each residential solar PV interconnection software, PRECISE assesses the affect of the interconnection proposal and evaluates the necessity to use sensible inverter capabilities.

“The task to determine optimal smart inverter settings in order to maximize our PV hosting capacity will become more complex and time intensive as the number of PV interconnection applications increase,” Hassan provides. Smart inverter capabilities will be the deciding issue on whether or not an interconnection should be downsized or not, and PRECISE allows that analysis, leveraging inverter capabilities as wanted, to assist accommodate extra solar onto the grid.

To make PRECISE occur, NREL labored carefully with a SMUD staff that included greater than 20 personnel working over a number of departments on the utility – together with geographical data system (GIS) consultants, superior metering infrastructure leads, distribution engineers, database directors, software directors, data expertise mission managers and enterprise course of consultants.

NREL’s mission staff included Kapil Duwadi, who performed the position of software developer, Aadil Latif, who automated the modeling of SMUD’s total distribution system, and Killian McKenna, who oversaw the hassle.

Close collaboration between NREL engineers and a various SMUD staff was important to the profitable integration and automation of PRECISE. The mission was the primary automation of the technical interconnection analysis strategy of its form, one that would function a template for a lot of utilities that want to automate the rising problem of evaluating new interconnection requests.

“PRECISE is a cutting-edge PV interconnection evaluation tool that enables utilities to cost-effectively host more solar,” Hassan says.

Given this achievement, NREL and SMUD are exploring future collaborations collectively, now that PRECISE has linked the varied utility information units (e.g., meter information, GIS, interconnection purposes) wanted for automated analysis of recent distributed energy assets. PRECISE may now be utilized to giant business solar websites, to evaluate battery energy storage, or to judge the affect of electrical autos as they hook up with the grid.

“The future for grid planning and operations is increased automation for evaluating the health, impacts, and opportunities of increasing levels of distributed energy resources,” McKenna mentions. “PRECISE is a first step of many to reach that future.”


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