Integration of Utility Distributed Energy Resource Management System and Aggregators for Evolving Distribution System Operators

Abstract

With the rapid integration of distributed energy resources (DERs), distribution utilities are faced with new and unprecedented issues. New challenges introduced by high penetration of DERs range from poor observability to overload and reverse power flow problems, under-/over-voltages, maloperation of legacy protection systems, and requirements for new planning procedures. Distribution utility personnel are not adequately trained, and legacy control centers are not properly equipped to cope with these issues. Fortunately, distribution energy resource management systems (DERMSs) are emerging software technologies aimed to provide distribution system operators (DSOs) with a specialized set of tools to enable them to overcome the issues caused by DERs and to maximize the benefits of the presence of high penetration of these novel resources. However, as DERMS technology is still emerging, its definition is vague and can refer to very different levels of software hierarchies, spanning from decentralized virtual power plants to DER aggregators and fully centralized enterprise systems (called utility DERMS). Although they are all frequently simply called DERMS, these software technologies have different sets of tools and aim to provide different services to different stakeholders. This paper explores how these different software technologies can complement each other, and how they can provide significant benefits to DSOs in enabling them to successfully manage evolving distribution networks with high penetration of DERs when they are integrated together into the control centers of distribution utilities.

Distributed energy resource management systems—DERMS: State of the art and how to move forward

“…As discussed in previous sections, centralized DER management solutions evolved as a response to inability of legacy control centers (mainly equipped with SCADA and/or DMS) to cope with DERs, and challenges that their integration imposes to the distribution grid assets and operation of emerging distribution systems—Path 1 in Figure 1. To provide a proper awareness of the entire grid with all its assets, as well as of the impact that DERs have on the grid, these centralized software solutions need to be grid‐aware—they need to provide accurate network model with all the grid assets considered in the model (Anaya, 2021; Schneider Electric, 2019; Siemens, 2021; Strezoski et al, 2022). Moreover, in addition to the traditional model, they need to provide an ability to represent all DERs, with every characteristic properly modeled within an appropriate representation that corresponds to the timescale of interest.…”

“…These include rated and maximum powers, number of phases (three‐phase or a single‐phase DER), rated currents and voltages, internal impedance values, contractual obligations, points of common couplings (PCCs), network and circuit topologies, and the method used for connection to the grid, but also in the case of inverter based DERs (IBDERs), functionalities that inverters may provide (e.g., grid‐forming vs. grid‐following, frequency response, voltage support, ride‐through, etc.) (ABB, 2020; General Electric, 2021; Schneider Electric, 2019; Siemens, 2021; Strezoski et al, 2022; Strezoski & Stefani, 2021). Further, and on top of the accurate network model, to provide awareness of the precise grid conditions in real time, these software solutions must deploy state of the art power flow and state estimation algorithms that are constantly supplied by real‐time SCADA and Advanced Metering Infrastructure (AMI) measurements, load and generation forecasts, real‐time topology, and as‐operated switching state from the field, as well as planned schedules from DERs based on their market participation.…”

“…Most of the major vendors agree that a Utility DERMS shall contain a comprehensive real‐time module for management of emerging distribution grids with high penetration of DERs (ABB, 2020; General Electric, 2021; Open Systems International, 2020; Schneider Electric, 2019; Siemens, 2021), as well as computational efficiency to handle high rate of data input and networks at scale. However, some of the more advanced Utility DERMS solutions contain a planning module (which are slower in computational processing), as well as a look‐ahead module (also slower in computational processing), besides the real time functions (which are the fastest in computational processing) (Schneider Electric, 2019; Strezoski et al, 2022). It is this author's belief that a Utility DERMS shall contain all three modules with enhanced computational capability (both algorithmically and computational architecture—including the choice of computing methods ranging from cloud to edge computing to cope with constraints that data volume, algorithmic complexity, and communication bandwidth impose), to be capable to properly mitigate all the DER‐imposed challenges.…”

“…It should be noted that DER Aggregators do not have access to an accurate network model and are unaware of the grid level upstream and its technical constraints, such as transformer and lines' overloads, relay settings and coordination, voltage limits, or reverse power flow constraints (Liu et al, 2021; SEPA, 2021; Strezoski et al, 2022; Strezoski & Stefani, 2021). Thus, even though services provided by DER Aggregators are highly important as they increase the overall flexibility of distribution grids by enabling the usage of the flexibility of small‐scale DERs, in most cases a DER Aggregator cannot be a sole DER management solution, as the schedules and dispatch of DERs provided by DER Aggregators alone may endanger grid assets, if they are not previously validated by the grid‐aware enterprise solution, such as a Utility DERMS (SEPA, 2021; Strezoski & Stefani, 2021).…”

“…To overcome these challenges and pave the way toward efficient energy transition, novel software solutions called Distributed Energy Resource Management Systems (DERMS) are emerging (EPRI, 2021a, 2021b; Faria, 2019; IEEE, 2021; Ilic et al, 2020; Petrovic et al, 2019; Rahman et al, 2021; Strezoski et al, 2022; Strezoski & Stefani, 2021; Strezoski, Stefani, et al, 2019; Strezoski, Vojnovic, et al, 2019; J. Wang, Chen, et al, 2015; Q. Wang, Zhang, et al, 2015; Wang et al, 2020). DERMS solutions aim to offer distribution system operators (DSOs), grid planners and engineers, as well as end‐customers and prosumers an opportunity to enter a new era of active and dynamic distribution systems, and even gain both technical and monetary benefits from this transition.…”