- Apr 14, 2021 3:35 pm GMT
First, there’s been an increase in the types of systems themselves—Distribution Automation (DA) and Distribution Management Systems (DMS)—as well as the Distributed Energy Resources (DER) that need to be integrated as renewables grow through the clean energy transition. At the same time, operators are moving away from traditional rules-based processes toward those that are based on algorithms. The result: an increased reliance within the control center on automated systems.
Although DMS systems are changing to meet these growing needs, the visibility they provide into the new technologies is limited. Not only that but their control scheme implementations are less flexible, and integration, coordination and management of DER alongside traditional devices is difficult.
That’s why the Electric Power Research Institute (EPRI) has spent nearly a decade working on algorithms to enable the evolution of DMS applications. With advanced operational analytics and control algorithms, grid modernization investments can be fully leveraged, and DER and the distribution system can operate in a coordinated fashion. Cost-effective, applicable, and scalable solutions enable increased reliability and efficiency for all customers at high levels of DER and move us closer to realizing the concept of the integrated grid.
Addressing the challenges of DER
To effectively incorporate DER into distribution system operations, monitoring and control capabilities must address the challenges presented by its high penetration while also exposing and realizing the operational benefits of these new resources. In other words, DER must be recognized as any other controllable resource that has certain capabilities and limitations that can be considered and leveraged.
Working alongside utilities in New York, EPRI has developed and tested advanced DMS applications for seamless DER operation in three focus areas. From 2013-2018, EPRI focused in particular on the impacts of DER on Volt/VAR and Distribution Automation/Fault Location Isolation and Service Restoration (FLISR), developing proof of concept algorithms that incorporate monitoring and rudimentary control of DER into the algorithms.
Also, during that time, EPRI embarked on a line of research dedicated to better understanding the operating characteristics of Distribution System State Estimation (DSSE) algorithms that are being used with new DMS deployments. These efforts laid the groundwork for the evolution that was required within distribution operational tools.
Leveraging this work, EPRI partnered with the New York State Energy Research and Development Authority (NYSERDA) to advance operational analytics and control algorithms that enable the distribution system and DER to operate in a coordinated fashion. Working with three New York utilities, this project prototyped the next generation of DMS algorithms. The project team simulated and tested Volt/VAR and DA/FLISR algorithms on actual utility feeder models, as well as explored the enhanced measurement/sensing capabilities on the distribution system to determine how they can be used to optimize the accuracy of DSSE models and situational awareness.
New algorithms for DER integration
DSSE: The foundational DSSE algorithm likely will be a critical component of DMS algorithms in the future. That’s because the size, type and location of distributed energy resources will lead to a distribution system that is unable to be observed without this capability. Our project provided new insights into:
- The sensitivity of DSSE results to many key factors; and
- The development of an entirely new way to model DSSE behavior that can be replicated and used for additional sensitivity analyses.
FLISR: The FLISR algorithm requires some significant enhancements before it is ready for a distribution system with high penetration DER. This project:
- Proposed and evaluated enhanced FLISR logic that mitigates one of the key challenges that will be presented in the near future—masked load;
- Investigated FLISR as one of many Optimal Network Reconfiguration (ONR) algorithms that are running at all times on the DMS, managing not just the initial automated restoration steps but also configuration decisions throughout the entire process until the feeders are switched back into normal configuration; and
- Supports operators managing high DER penetration feeders by mitigating overloads and voltage issues when the feeders are in “as built” configurations by making temporary settings adjustments or temporary load transfers as necessary.
VVO: The Volt Var Optimization (VVO) algorithm requires significant enhancement to incorporate the monitoring and (eventual) control of DER assets. These enhanced algorithms will take the form of hybrid control schemes that perform functions as best served by the algorithm—locally, centrally and in between. This project detailed a new algorithm that has been thoroughly modeled and tested and is poised to be demonstrated in the field this year.
Demonstrating what’s possible
DER will fundamentally change electric distribution operations. It is critical that key control algorithms are out in front of this evolution, as unlocking these resources will be essential to reliably operating the future energy system. For EPRI, the next step for this work involves partnering with utilities and the vendor community to move these new algorithms into demonstration projects.
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