Engineering topics

Mahmud, Rasel

Publications and source records attributed to Mahmud, Rasel.

At least 37 records · Page 2

DOE OSTI2021

An Overview of Issues Related to IEEE Std 1547-2018 Requirements Regarding Voltage and Reactive Power Control

The revised Institute of Electrical and Electronics Engineers (IEEE) 1547 Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces (IEEE Std 1547-2018) was published in April 2018. This standard is one of the foundational documents in the United States needed for integrating distributed energy resources (DERs), including solar energy systems, with the electric distribution grid. The revised standard contains 11 chapters (clauses) and 8 annexes that comprise 136 pages. The revision is significantly different from the 2003 version, and it contains new concepts and new technical requirements. Each clause specifies information or requirements that apply to certain aspects important to the interconnection of DERs to the electric power system. Implementing the requirements necessitates a careful study of the underlying technical concept and requires the appropriate information required to calculate relevant settings and configurations. Various stakeholders have different roles in implementing the standard, and portions of the standard are directed toward a specific audience who must possess specialized information and technical training to use and apply the requirements. This document aims to (1) summarize a specific portion of the standard as concisely as possible and (2) provide the reader with introductory knowledge and information to support the utilization of the requirements.

14 SOLAR ENERGY↗

DOE OSTI2021

Informative Background on the Interoperability Requirements in IEEE Std 1547-2018

The intent of this document is to support local authorities governing interconnection requirements in adopting the most current requirements for interconnecting distributed energy resources (DERs) to the electric distribution system, as specified in the Institute of Electrical and Electronics Engineers Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces (IEEE Std 1547-2018 ). To create interconnection rules that successfully address policy goals, market trends, and technical requirements, electric service regulators need to be well informed of DER integration considerations. Interconnection processes and technical issues often overlap; the two are not easily segregated, and they are often considered and evaluated concurrently within the context of interconnection rulemaking. Accordingly, this document addresses both the technical issues and related process considerations.

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DOE OSTI2021

EMOS (Energy Management Optimization System) [SWR-21-46]

EMOS software performs a real-time hierarchal optimal control for energy systems like multi-port electric vehicles charging site with distributed energy resources (DERs) and energy storage systems (ESSs). It gathers information in real-time from electric vehicles, power grid, and DERs, solves a multi-objective energy management optimization problem, and output setpoint for chargers, ESS converters, DERs converters, and grid converters. The software incorporates a novel integration of two control tasks: a) An Energy Management Optimization (EMO), which is the brain of EMOS controller that gathers information in real-time from EVs [e.g., battery size, state-of-charge (SOC), desired SOC, and charge acceptance curve], grid (e.g., electricity price, allowed feeder capacity, ramp rate limit, and reactive power), and DERs (e.g., prediction for solar generation for PV systems). It solves a control optimization problem in real-time to find optimal setpoint for ESSs power dispatch, EVs charging rate, and grid inverters. The objectives are to (1) minimize the charging cost considering grid energy, demand charges, and battery energy, (2) minimize charging time to meet fast charging criterion, (3) keep high energy level on ESSs at the end of an operating period, while satisfying constraints related to grid, EVs, and power converters. b) Real-Time Energy Management System (RT-EMS) is a rule-based algorithm that has faster response than EMO. It receives optimal setpoint from EMO and actual measurements from the system and modify the setpoint to compensate for any fast disturbance in the system, until a new optimum solution is received. Fast disturbances may include vehicle connect/disconnect, unpredicted variation in DERs profiles, variation in grid voltage, errors in PV generation prediction, and others. In addition, RT-EMS regulates voltage at point of common coupling (PCC) by managing reactive power of grid converters.

Mohamed, Ahmed↗

DOE OSTI2021

Grid Voltage Control Analysis for Heavy-Duty Electric Vehicle Charging Stations

This paper presents an analysis of grid voltage control strategies for heavy-duty electric vehicle charging stations. The performance of three voltage control approaches—including power factor control, standardized volt-volt ampere reactive (VAR) curve control, and customized volt-VAR curve control—are investigated and evaluated for three different sizes of charging stations, including a single-port charging station, a midsized three-port charging station, and six-port travel center. The charging stations are placed on multiple locations of four different types of distribution systems to obtain a comprehensive performance analysis of the voltage control approaches under different scenarios. To quantitively compare the performance of the three voltage control approaches, a series of metrics are designed to quantify the performance and contribute to the comprehensive analysis.

47 OTHER INSTRUMENTATION↗

DOE OSTI2021

Fast Grid Frequency Support from Distributed Energy Resources

This report describes research related to electric power system frequency support from inverter-coupled distributed energy resources (DERs). This research was initiated under the U.S. Department of Energy’s Grid Modernization Laboratory Consortium (GMLC) and also contains work funded through a Cooperative Research and Development Agreement with Hawaiian Electric. The purpose of this report is to summarize the findings of simulations, hardware testing, power hardware-in-the-loop (PHIL) simulation, and analysis examining the effects of DER frequency support on the Oahu power system. This report also includes recommendations for consideration in the use of DER grid frequency support functionality, and related topics. Note that a previous GMLC Technical Report from this project also provided specific recommendations for the activation of one specific grid frequency support function, frequency-watt control, for overfrequency events in Hawaii. Those recommendations included recommended frequency-watt control settings, which have since been approved by the Hawaii Public Utilities Commission on October 20, 2017, for system-wide activation. This report builds on the previous report by considering not only overfrequency events but also underfrequency events, and by considering distributed energy storage systems in addition to photovoltaic (PV) systems.

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DOE OSTI2021

Grid Voltage Control Analysis for Heavy-Duty Electric Vehicle Charging Stations: Preprint

This paper presents an analysis of voltage control strategies for heavy duty electric vehicle (EV) charging stations. The performance of three voltage control approaches including power factor control, preset volt-var curve control, and customized volt-var curve control, have been investigated and evaluated for three different sizes of charging stations, including single-port small charging station, three-port middle size charging station, and 6-port travel center. The charging stations have been placed on various locations of four different types of distribution systems, to obtain a comprehensive performance analysis of the three voltage control approaches under different scenarios. To quantitively compare the performance of the three voltage control approaches, a series of metrics have been designed to quantify the performance and contribute to the comprehensive analysis summary.

47 OTHER INSTRUMENTATION↗

DOE OSTI2020

Reduced-Order Parameterized Short-Circuit Current Model of Inverter-Interfaced Distributed Generators

The short-circuit response of inverter-interfaced distributed generators (IIDGs) is not adequately represented in many conventional protection studies. This paper presents an in-depth analysis of IIDG behavior during grid faults and proposes a more accurate reduced-order parameterized short-circuit current (RPSC) model of inverters. Typical inverter components are thoroughly investigated to identify those that play dominant roles during faults. The paper shows that the current limiter is the dominant factor for the steady-state fault-current of inverter; while the inverter filter along with the severity of the voltage disturbance largely determine the initial transient spike of inverter fault current. The proposed model is low-order and can be used in large scale simulations. The parameters of the proposed RPSC model can be extracted from laboratory experiments without requiring proprietary manufacturer information. The proposed fault-current model is analogous to the well-known synchronous machine model that segregates the inverter fault current into subtransient, transient, and steady-state fault currents. Finally, experimental and simulation tests are presented to validate the model.

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DOE OSTI2020

Fault Response of Distributed Energy Resources Considering the Requirements of IEEE 1547-2018

Inverter-based DER responses to faults on the electric power system are different than those of conventional generators and are often poorly understood. Inverter fault responses are largely software-defined, within physics-based constraints. DERs are regulated by standards and grid codes that also constrain their responses. Though fault response of DERs will vary widely, for any DER following any particular standard, a pattern of fault response can be synthesized by observing that particular standard. In this paper, the recently published IEEE 1547-2018 is examined to explore the general fault response of any DER that follows IEEE 1547-2018. Additionally, an IEEE 1547-2018 compliant inverter model is developed and tested in simulation to find the fault response, and that response is compared with the fault response of a commercial off-the-shelf inverter.

41 EE - Solar Energy Technologies Office (EE-4S)↗

DOE OSTI2020

Impact of Aggregated PV on Subsynchronous Torsional Interaction: Preprint

This paper investigates induced oscillation (specifically subsynchronous torsional interactions) in power systems arising from photovoltaic (PV) power modulation. Time domain simulations of a modified IEEE first-benchmark system are presented and analyzed. In the IEEE benchmark system, a PV generator was added at the same bus where the synchronous generator is connected. The impact of different parameters of the PV inverters volt-volt-ampere reactive (volt-var) curve on SSTI is examined. The most severe impact found arises from the time response of the inverters reactive power change. A second-order time response with natural frequency matching the rotor speed deviation oscillation frequency and low-damping ratio quickly drives the system to an unstable region. Although it is highly unlikely that conditions necessary for distributed energy resource-induced oscillations would occur in the field, with knowledge of this vulnerability in mind, inverters' control parameters can be designed to avoid it.

aggregated↗

DOE OSTI2020

Impact of Aggregated PV on Subsynchronous Torsional Interaction

This paper investigates induced oscillation (specifically subsynchronous torsional interactions) in power systems arising from photovoltaic (PV) power modulation. Time domain simulations of a modified IEEE first-benchmark system are presented and analyzed. In the IEEE benchmark system, a PV generator was added at the same bus where the synchronous generator is connected. The impact of different parameters of the PV inverters’ volt-volt-ampere reactive (volt-var) curve on SSTI is examined. The most severe impact found arises from the time response of the inverter’s reactive power change. A second-order time response with natural frequency matching the rotor speed deviation oscillation frequency and low-damping ratio quickly drives the system to an unstable region. Although it is highly unlikely that conditions necessary for distributed energy resource-induced oscillations would occur in the field, with knowledge of this vulnerability in mind, inverters' control parameters can be designed to avoid it.

41 EE - Solar Energy Technologies Office (EE-4S)↗

DOE OSTI2020

Distributed Cooperative Control of Hybrid AC/DC Microgrid

This paper presents a distributed cooperative control-based power management algorithm for a hybrid AC/DC microgrid. The proposed algorithm for a hybrid microgrid system controls the power flow through the interface converter between the AC and DC microgrids. This algorithm allows power sharing between the distributed generators in the microgrid according to their power ratings. Moreover, it enables the fixed scheduled power delivery through the interface converters in both directions at different operating conditions while maintaining voltage regulation and improving the frequency profile. The effectiveness of the controller is confirmed by simulation.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2019

Distributed Cooperative Control of Hybrid AC/DC Microgrid

This paper presents a distributed cooperative control-based (DCC) power management algorithm for a hybrid AC/DC microgrid. The proposed algorithm for a hybrid microgrid system controls the power flow through the interface converter between the AC and DC microgrids. This algorithm allows power sharing between the distributed generators in the microgrid according to their power ratings. Moreover, it enables the fixed scheduled power delivery through the interface converters in both directions at different operating conditions while maintaining voltage regulation and improving the frequency profile.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2019

Accelerating Systems Integration Standards (ACCEL)

This is the final report for a project to support the development of systems integration standards. The scope of work undertaken by the multi-laboratory team was to facilitate standards development and to help expedite the process in three important standards identified under the SunShot National Laboratory Multiyear Partnership (SuNLaMP) grid performance and reliability topic area.

14 SOLAR ENERGY↗

DOE OSTI2019

Distributed Cooperative Control of Hybrid AC/DC Microgrid: Preprint

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2019

Laboratory-Scale Microgrid System for Control of Power Distribution in Local Energy Networks - Part I: Theory and Design

One of the promising solutions to achieve sustainable energy systems in future smart cities is to deploy microgrids in local energy networks. Due to the decentralized nature of microgrids, large-scale utilization of these resources will increase the reliability of the energy systems as well as facilitating the integration of renewable energy resources to enable more environmentally-friendly energy network. This chapter presents development of a highly reconfigurable, laboratory-scale microgrid testbed. The proposed microgrid system integrates several distributed generation (DG) units representing photovoltaic panel, wind turbine, battery energy storage and etc. The schematic of the proposed system can be customized to investigate numerous grid architectures and control scenarios. In this study, the loads and energy resource allocation are realized by assessment of the loads and resources priority. Therefore, a hierarchical procedure will take place to allocate the power to different buses in microgrid. In the next chapter, we describe the test-bed implementation of the designed microgrid.

design↗

DOE OSTI2019

Laboratory-Scale Microgrid System for Control of Power Distribution in Local Energy Networks - Part II: Implementation and Case Study

In this chapter, we provide the detailed implementation of the proposed microgrid framework in part I. As a case study, a droop-based load sharing algorithm with the capability of controlling the active and reactive power have been implemented. Several load sharing scenarios have been studied to verify the capability of the suggested prototype in performance evaluation and verification of different control strategies in microgrid systems. The performed experiments confirm the capacity of the proposed structure in microgrid research and development (R&D), as well as education.

design↗

DOE OSTI2018

Validating the Test Procedures Described in UL 1741 SA and IEEE P1547.1

14 SOLAR ENERGY↗

DOE OSTI2018

Validating the Test Procedures Described in UL 1741 SA and IEEE P1547.1: Preprint

This paper investigates the test procedures specified in UL 1741 SA and the upcoming revision to IEEE P1547.1. A 550 kVA photovoltaic inverter was chosen for the tests. This research reveals some of key the components to consider while doing certification tests for UL 1741 SA and IEEE P1547.1. This paper also identifies some issues requiring consideration for future releases of the standard, i.e. IEEE P1547.1. This paper investigates the test procedures specified in UL 1741 SA and the upcoming revision to IEEE P1547.1. A 550 kVA photovoltaic inverter was chosen for the tests. This research reveals some of key the components to consider while doing certification tests for UL 1741 SA and IEEE P1547.1. This paper also identifies some issues requiring consideration for future releases of the standard, i.e. IEEE P1547.1.

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