Making the Grid Smarter: Primer on Adopting the New IEEE Std 1547-2018 for Distributed Energy Resources

The report, Making the Grid Smarter: Primer on Adopting the New Institute of Electrical and Electronics Engineers Standard 1547-2018 (IEEE Std 1547-2018) for Distributed Energy Resources, provides an overview and explanation of the major revisions in IEEE Std 1547-2018 and the key issues for states to consider.

Options for State Regulators and Utilities

The new standard now provides a plethora of options that state regulators and utilities can choose from based on their current technology, anticipated DER penetration level, location, and other factors. The report provides an overview and explanation of IEEE Std 1547-2018 and a synopsis of the issues that state regulators and utilities need to consider while adopting it. This document is an abridged version of the main report and has been prepared from a regulator's perspective to highlight the points relevant to them.

According to the report, the tested and verified 1547-compliant DER equipment would be commercially available by 2022. It is important to ensure that the rules are in place by then. The document strongly urges the states to begin updating their rules in accordance with the updated standard now. States that do not have a rule governing interconnection could begin the process with IEEE Std 1547-2018, which would ensure adequate DER capabilities for those states that do not anticipate a high penetration and help streamline the rollout of the standard for states with multiple regulated utilities.

First, the state interconnection rules need to clarify where and how the reference point of applicability is set for different DERs. Default values for functional settings (e.g., trip and voltage regulation settings) will help in simplifying the project verification process but these should evolve over time. The most important part of the update for the state regulatory commissions and utilities is to coordinate with the Regional Reliability Coordinator, Regional Transmission Organization and Independent System Operator to evaluate, select and assign "performance categories" to the DERs based on technology or use-case. These categories determine how reliably DERs can maintain generation during transmission system disturbances. The abnormal category contains frequency-droop setting that might result in reduction in active power from DERs. Regulators need to consider if and to what extent customers should be aware of the reduction in active power and what protective measures can be employed against the loss.

Voltage regulation functions could increase the DER hosting capacity when deployed early on and thus needs to be accounted for in hosting capacity analysis efforts. The state regulators and utilities will need to determine when these functions must be turned on, which function and settings to be utilized (only one of the four reactive power functions can be activated at a time for an individual DER) and how enabling these functions will interact with the interconnection rules. Further, voltage regulation has the possibility of reducing the generation output of a DER that can affect the project economics. At this point, it is a challenge to predict the effect of voltage dependent function on DER generation over its lifetime. Hence, regulators need to consider adopting some customer protection measures. Regulators first need to develop guidelines to track and report generation losses in DERs occurring due to voltage regulation. They should also be aware of when, where, and how often these functions are utilized and identify possible corrective measures (ex: DER settings, monetary compensation) to minimize the loss and benefit the grid.

In addition to the autonomous functions discussed above, state interconnection rules will need to determine how and what communication protocols will be used. Regulators and utilities need to specify the conditions for remote curtailment, turning off and changes to certain settings or functions. Regulators need to evaluate the cost impact to the customers in updating or revamping their systems to enable communications protocol.

Further, regulators may review utility practices to ensure that customers are eliminated from the burden of excessive grounding or unnecessary equipment for DERs. State regulators and utilities need to be cognizant of the updated standard that readily addresses certain concepts such as load rejection overvoltage which impact the current interconnection studies and technical screening process. State regulators are also recommended to adopt explicitly the conditions for intentional islanding to gain clarity on their interaction with the existing grid.

Although IEEE Std 1547-2018 implies certain export control systems necessary to prevent DERs from exporting beyond the specified levels, it does not provide specific guidance on export control mechanisms. One of the important considerations for the state regulators is limiting power export and exercising system controls during inadvertent export. The report provides a few options available in this regard and suggests state rules to define this setting like Hawaii, California, or Nevada did for non-exporting systems.

Finally, the state interconnection rules, while adopting the IEEE Std 1547-2018, should ensure consistency and harmonization among the different utilities. The rules need to provide clarity on when site-specific settings maybe more suitable than upgrades. The regulators should also address how the component maintenance or replacements needs to be handled. Clear guidance is required to carry out such activities in a consistent and cost-effective manner. States are required to work swiftly to adopt the new standard in order to facilitate smooth transition and exploit the advanced features of the DERs for better integration and improved system power quality.