Managing Distributed Energy Resources

Managing Distributed Energy Resources

ACS’s Distributed Energy Resource Management System (DERMS) is a suite of distributed applications built to maximize DER capability and effectiveness, including increased hosting capacity, while mitigating adverse effect on the grid.

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Managing Distributed Energy Resources

ACS’s Distributed Energy Resource Management System (DERMS) is a suite of distributed applications built to maximize DER capability and effectiveness, including increased hosting capacity, while mitigating adverse effect on the grid

Using Volt-Var Optimization (VVO), Load Forecasting, and System Reconfiguration, Centrix DERMS is a flexible software solution, inter-operable with existing systems, cost effective to deploy, and that can scale and expand with the utilities’ needs.

With an ever-growing presence of DERs in the power distribution system, utilities need new solutions to optimize the value of these assets as well as limit the adverse effects that can arise such as voltage violations and reverse power flow as inverter-based generation increases and load/generation becomes more intermittent.

ACS deploys a multi-staged solution that combines monitoring and controlling DER assets with system optimization to effectively meet the challenges presented by growing DER penetration and related congestion.

PRISM

Centrix DERMS provides a utility tool for:

System Voltage Optimization

Real-time VVO
Utilization of smart inverters for fine tuning VVO

Forecasting & System Reconfiguration

Utilize forecasting (weather & loading) to identify potential system issue prior to happening
Provide switching plans to reconfigure system due to DER congestion

Real-Time System Reconfiguration & DER Curtailment

In real-time, dynamically reconfigure system if unexpected injection violations occur
Controlled limited DER curtailment based on injections at Point of Common Coupling (PPC)

Using Volt-Var Optimization (VVO), Load Forecasting, and System Reconfiguration, Centrix DERMS is a flexible software solution, inter-operable with existing systems, cost effective to deploy, and that can scale and expand with the utilities’ needs.

With an ever-growing presence of DERs in the power distribution system, utilities need new solutions to optimize the value of these assets as well as limit the adverse effects that can arise such as voltage violations and reverse power flow as inverter-based generation increases and load/generation becomes more intermittent.

ACS deploys a multi-staged solution that combines monitoring and controlling DER assets with system optimization to effectively meet the challenges presented by growing DER penetration and related congestion.

PRISM

Centrix DERMS provides a utility tool for:

System Voltage Optimization

Real-time VVO
Utilization of smart inverters for fine tuning VVO

Forecasting & System Reconfiguration

Utilize forecasting (weather & loading) to identify potential system issue prior to happening
Provide switching plans to reconfigure system due to DER congestion

Real-Time System Reconfiguration & DER Curtailment

In real-time, dynamically reconfigure system if unexpected injection violations occur
Controlled limited DER curtailment based on injections at Point of Common Coupling (PPC)

  • System Voltage Optimization

    Control scheme is based on three-pass iterative approach:

    Minimize Var losses by controlling distribution capacitor

    Flatten voltage profile after impact of capacitor switching by controlling transformer Load Tap Changers (LTCs) and Voltage Regulators (VRs)

    Fine control of voltage based on ability of smart inverter (if available) to affect voltage at the point of common coupling/injection points

  • Forecasting & System Reconfiguration

    Utilize Forecasting Data

    Look at sliding 24-hour window of forecasting data

    Utilize forecast data to continuously run load flow analysis to identify injection violations

    If it is determined VVO is unable to accommodate injection, DERMS attempts to identify possible feeder reconfigurations

  • Real-Time System Reconfiguration & DER Curtailment

    If injection limits are violated in real-time, DERMS will look to reconfigure system in a synchronized fashion

    Voltages across normally open switches will be monitored and adjusted if needed prior to closing switch to an adjacent feeder

    If it is determined violation thresholds cannot be resolved from system reconfiguration, DERMS will calculate maximum injections allowed at each common coupling point and curtail DER as necessary

  • Timely Development

    The development of a DERMS has been a logical progression of the distribution control and automation systems ACS has been delivering for over 40 years.

  • Advanced Control

    The advanced control of transformer load tap changers, substation and feeder capacitor banks, feeder breakers, voltage regulators, and feeder sectionalizing devices needed to optimize the performance of DERs is available within the PRISM platform.

  • Seamless Integration

    Our solutions are designed to integrate seamlessly into legacy systems and existing equipment.

  • Advanced Automation

    Our DERMS is an advanced application of existing automation systems such as voltage regulation and optimization (VVO) as well as automated fault location isolation and service restoration (FLISR) with a combined goal of maximizing the injection of renewables in a multitude of scenarios that includes the use of energy storage systems.

  • Extending Our Reach

    Advancements in communications are allowing us to extend our reach and collect large amounts of meaningful data from a variety of devices, including DERs, to further optimize grid performance as well as contribute to additional reliability, and resiliency.

  • Flexible Location

    A DERMS can be applied at a centralized location typical to legacy utility management systems, distributed closer to the resources whose operation needs to be coordinated, or a combination of both. The choice is dependent on the utility’s approach, infrastructure, and needs at the time, which can vary widely.

Distributed Architecture

Centrix DERMS enables a BUILD-AS-YOU-GROW approach to begin DER support gradually while achieving immediate gains in feeder reliability and resiliency—starting while penetration levels may be minimal and have not yet presented operational issues for the network.  The architecture of Centrix provides utilities with the option of deploying modules with increasing functionality and complexity as their needs dictate, beginning with the introduction of Integrated Volt-Var Control (VVO).

The available Centrix DERMS application modules include:

  • Real-time VVO, for Volt-Var control extended to include optimization and control capability from inverter-based generation.
  • Energy Storage optimization for charge/discharge
  • Synchronized Load Transfer (SLT) for feeder reconfiguration through remote switching
  • Maximum feeder Injection Capability (MIC) to optimize the injection amount and location

The individual modules are highlighted in the following sections.

Fully Autonomous Operation

The DERMS applications run in fully automatous mode. During anticipated or real-time violations that the DERMS applications cannot resolve, the system performs a synchronized feeder reconfiguration.  If feeder reconfiguration cannot solve the violations, will curtail the unit injection to the maximum output allowed at the point of common coupling.

During switching where each side of a switch is fed by different buses, Centrix monitors the voltage across the open switch and will utilize the IVVC function to adjust the voltage within allowable limits prior to operation.  the allowable range needed to safely perform a close may be exceeded.

Integrated Volt-Var Control (VVO) Integrated Volt-Var Control (VVO) for distributed energy resources VVO runs in real-time in Automatic mode on the Centrix platform. The base VVO function manages typical feeder violations by issuing controls in real-time to optimize the voltage profile and to reduce losses (improve the power factor) for each feeder under its control. The user can establish the control objective for each feeder, such as Voltage minimization, Var loss minimization, or both.  The primary real-time operational objective of VVO is to avoid feeder violations which may threaten the reliability of the feeder’s continued operation.

VVO adds support for control of PV inverters, as well as distributed generation and battery storage.  VVO serves to alleviate voltage issues at the point of common coupling and in reverse flow direction that result from increased DER penetration on the system.  The secondary objective of VVO is to avoid curtailment as much as possible so that the renewable inverter can inject the maximum possible generation.

Energy Storage Optimization

The Energy Storage Optimization function can control the output of Battery Energy Storage Systems (BESS) to inject the proper amount of real and reactive power and to operate in charge and discharge modes as appropriate. For example, where utilities require the power flow to maintain a direction consistent with the relay protection settings, the current flow direction can be enforced with the effective use of the storage system.

Synchronized Load Transfer

The Synchronized Load Transfer (SLT) application runs in conjunction with VVO in real-time.  If the projected or forecast injection is greater than can be effectively managed through VVO control, the system will explore the effect of network switching.

SLT is called by VVO when feeder DER injection is excessive, resulting in voltage violations and reverse power flow.  If VVO cannot resolve the violations in real-time, then SLT will perform feeder switching to transfer load or DER generation to/from another feeder (or a combination of both).  If no possible switching scenarios exist to resolve the violations, then VVO will resort to curtailment of the renewable generation.

Maximum Injection Capability

Voltage and line limit violations due to load and/or generation variations may fall outside of the range of control that IVVC is able to resolve. In these situations, it is necessary to calculate the Maximum Injection Capability (MIC) at each injection point of common coupling on the feeder in terms of watts and vars injection. Curtailment of inverter-based generation is the last resort to protect the feeder by maintaining operation within limits. MIC will supply the VVO with the maximum allowable injection for each controllable DER on the feeder.

ACS offers a suite of applications to integrate and manage these resources:

PRISM DMS

A Centralized Enterprise System that can be easily scaled to include Outage Management, Energy Management, and a host of other applications.

CENTRIX DERMS

A Distributed Management system that can be deployed for advanced functionality including optimization and automation exactly where it is needed.

A recent 2017 study has concluded that there are advantages to applying an advanced level of automation at the substation level to optimize a system while still reporting critical information back to central operations.

Some of these advantages include speed and resiliency. Localized intelligence alleviates latency concerns that may be encountered with centralized control, especially during widespread outage conditions related to extreme weather or other service interruptions. Distributed intelligence and control allows for an island or localized state that can maintain effective operation independent of a central system.

The study findings conclude that the ACS CENTRIX DERMS:

  • Reduced and prevented reverse power flow
  • Flattened voltage profiles
  • Regulated voltage swings due to load fluctuations faster controlled from the substation
  • Reduced the number of operations of assets such as voltage regulators, switched capacitor banks, etc.
  • Reduced power loss
  • Improved power factor
  • Dynamically adjusted protection settings

A recent 2017 study has concluded that there are advantages to applying an advanced level of automation at the substation level to optimize a system while still reporting critical information back to central operations.

Some of these advantages include speed and resiliency. Localized intelligence alleviates latency concerns that may be encountered with centralized control, especially during widespread outage conditions related to extreme weather or other service interruptions. Distributed intelligence and control allows for an island or localized state that can maintain effective operation independent of a central system.

The study findings conclude that the ACS CENTRIX DERMS:

  • Reduced and prevented reverse power flow
  • Flattened voltage profiles
  • Regulated voltage swings due to load fluctuations faster controlled from the substation
  • Reduced the number of operations of assets such as voltage regulators, switched capacitor banks, etc.
  • Reduced power loss
  • Improved power factor
  • Dynamically adjusted protection settings

Prism Derms

Decrease Linedrop Voltage
0%
Increase PV Power
0%
Decrease Power Losses
0%
Increase Power Factor
0%
Peak Voltage Reduction
0%

DERMS works as follows

PRISM DERMS issues control signals to feeder devices with the objective to optimize the operation of the feeder network. DERMS lowers the end of line Voltage and the line drop Voltage using LTC and regulators and reduces feeder losses through improvement of the power factor with capacitor switching. DERMS specific control to optimize the feeder includes dynamic control of the inverter’s real and reactive power injection from renewables such as photoVoltaic (PV) distributed energy resources and energy storage.

Capacitors

Energy Storage System

Renewable DER

Switches

Transformer LTC

Voltage Regulators

What can PRISM DERMS and CENTRIX DERMS do for you?

Download the PRISM Renewable Suite Brochure

What can PRISM DERMS and CENTRIX DERMS do for you?

Download the PRISM Renewable Suite Brochure