Mehmet Hazar Cintuglu

Real-Time Implementation of Multiagent-Based Game Theory Reverse Auction Model for Microgrid Market Operation

This paper presents a real-time implementation of a multiagent-based game theory reverse auction model for microgrid market operations featuring conventional and renewable distributed energy resources (DER). Studies were conducted on a grid connected microgrid consisting of a synchronous generator, two inverter-based generation units, and a combined load. The multiagent-based platform was applied to monitor, control, and perform the reverse auction process of DERs. A competitive game-theory reverse auction model was investigated to schedule the DER unit commitment with an hour-ahead market approach for the 24 h of the day. The proposed methodology was realistically implemented and operated at the Florida International University smart grid test system. The investigation shows that the proposed algorithm and the industrial hardware-based infrastructure can be implemented in the existing electric utility grid as new assets of the system are added.

A Survey on Smart Grid Cyber-Physical System Testbeds

An increasing interest is emerging on the development of smart grid cyber-physical system testbeds. As new communication and information technologies emerge, innovative cyber-physical system testbeds need to leverage realistic and scalable platforms. Indeed, the interdisciplinary structure of the smart grid concept compels heterogeneous testbeds with different capabilities. There is a significant need to evaluate new concepts and vulnerabilities as opposed to counting on solely simulation studies especially using hardware-in-the-loop test platforms. In this paper, we present a comprehensive survey on cyber-physical smart grid testbeds aiming to provide a taxonomy and insightful guidelines for the development as well as to identify the key features and design decisions while developing future smart grid testbeds. First, this survey provides a four step taxonomy based on smart grid domains, research goals, test platforms, and communication infrastructure. Then, we introduce an overview with a detailed discussion and an evaluation on existing testbeds from the literature. Finally, we conclude this paper with a look on future trends and developments in cyber-physical smart grid testbed research.

Protection of Autonomous Microgrids using Agent-Based Distributed Communication

This paper presents a real-time implementation of autonomous microgrid protection using agent-based distributed communication. Protection of an autonomous microgrid requires special considerations compared to large-scale distribution networks due to the presence of power converters and relatively low inertia. In this paper, we introduce a practical overcurrent and a frequency-selectivity method to overcome conventional limitations. The proposed overcurrent scheme defines a selectivity mechanism considering the remedial action scheme of the microgrid after a fault instant based on feeder characteristics and the location of the intelligent electronic devices (IEDs). A synchrophasor-based online frequency-selectivity approach is proposed to avoid pulse loading effects in low inertia microgrids. Experimental results are presented for verification of the proposed schemes using a laboratory-based microgrid. The setup was composed of actual generation units and IEDs using the IEC 61850 protocol. The experimental results were in excellent agreement with the proposed protection scheme.

Control of a Hybrid AC/DC Microgrid Involving Energy Storage and Pulsed Loads

This paper presents a real-time coordinated control of the hybrid ac/dc microgrids involving energy storage and pulsed loads. Grid-isolated hybrid microgrid applications require special considerations due to the intermittent generation, online energy storage control, and pulsed loads. In this study, we introduce a comprehensive frequency and voltage control scheme for a hybrid ac/dc microgrid consisting of a synchronous generator, solar generation emulator, and bidirectional (ac/dc and dc/dc) converters. A bidirectional controlled ac/dc converter with an active and reactive power decoupling technique is used to link the ac bus with the dc bus, while regulating the system voltage and frequency. A dc/dc boost converter with a maximum power point tracking function is implemented to maximize the intermittent energy generation from solar generators. Current-controlled bidirectional dc/dc converters are applied to connect each lithium-ion battery bank to the dc bus. Lithium-ion battery banks act as energy storage devices that serve to increase the system resiliency by absorbing or injecting power. Experimental results are presented for verification of the introduced hybrid ac/dc power flow control scheme.

Frequency and voltage control of microgrids upon unintentional cascading islanding

Microgrids are small scale electricity networks comprising diverse distributed resources (DER) which can operate in grid-connected or islanded mode. An islanding situation may occur in a cascading way, where the DER types inside the islanded area have substantial impacts by means of control schemes. This paper presents a comprehensive study of the islanding process and the subsequent frequency and voltage control of different island schemes that comply with the IEEE 1547.4 grid code. Grid-connected operation, transition-to-island and islanded-mode operation of three different forms of cascading islanding were investigated. Studied islanding forms were a synchronous generator, inverter-based DER and a hybrid type. Experimental results are given in addition to simulation studies.

Development and Application of a Real-Time Testbed for Multiagent System Interoperability: A Case Study on Hierarchical Microgrid Control

This paper presents the development and application of a real-time testbed for multiagent system interoperability. As utility independent private microgrids are installed constantly, standardized interoperability frameworks are required to define behavioral models of the individual agents for expandability and plug-and-play operation. In this paper, we propose a comprehensive hybrid agent framework combining the foundation for intelligent physical agents (FIPA), IEC 61850, and data distribution service (DDS) standards. The IEC 61850 logical node concept is extended using FIPA based agent communication language (ACL) with application specific attributes and deliberative behavior modeling capability. The DDS middleware is adopted to enable a real-time publisher-subscriber interoperability mechanism between platforms. The proposed multi-agent framework was validated in a laboratory based testbed involving developed intelligent electronic device (IED) prototypes and actual microgrid setups. Experimental results were demonstrated for both decentralized and distributed control approaches. Secondary and tertiary control levels of a microgrid were demonstrated for decentralized hierarchical control case study. A consensus-based economic dispatch case study was demonstrated as a distributed control example. It was shown that the developed agent platform is industrially applicable for actual smart grid field deployment.

Control of hybrid AC/DC microgrid involving energy storage, renewable energy and pulsed loads

This paper proposes the coordinated control of a hybrid AC/DC power system with renewable energy source, energy storages and critical loads. The hybrid microgrid consists of both AC and DC sides. A synchronous generator and a PV farm supply power to the systems AC and DC sides, respectively. A bidirectional fully controlled AC/DC converter with active and reactive power decoupling technique is used to link the AC bus with the DC bus while regulating the system voltage and frequency. A DC/DC boost converter with a maximum power point tracking (MPPT) function is implemented to maximize the energy generation from the PV farm. Current controlled bidirectional DC/DC converters are applied to connect each lithium-ion battery bank to the DC bus. Lithium-ion battery banks act as energy storage devices that serve to increase the system stability by absorbing or injecting power to the grid as ancillary services. The proposed system can function in both grid-connected mode and islanding mode. Power electronic converters with different control strategies are analyzed in both modes in detail. Simulation results in MATLAB Simulink verify that the proposed topology is coordinated for power management in both AC and DC sides under critical loads with high efficiency, reliability, and robustness under both grid-connected and islanding modes.

Multiagent-Based Optimal Microgrid Control Using Fully Distributed Diffusion Strategy

This paper proposes a multiagent-based optimal microgrid control scheme using a fully distributed diffusion strategy. A two-level cooperative optimization multiagent system is adapted for distributed energy resources economic dispatch. The lower level implements an adaptive droop scheme based on online no-load frequency adjustments. The upper level implements distributed communication using diffusion between neighboring agents for optimal microgrid management. The proposed control scheme enables peer-to-peer communication among the agents without the necessity of a centralized controller, and simultaneously performs resource optimization while regulating the system frequency. The results are compared with centralized and consensus-based optimization algorithms. We have concluded that the proposed algorithm is superior over consensus algorithms in terms of convergence speed and utilizes reduced communication infrastructure compared to centralized controllers. Simulation demonstrations were conducted along with experimental results from a hardware-based microgrid using an industrial multiagent framework. The simulation and experimental results show that the proposed method and the agent framework can be deployed in real-world microgrids and offer superior decision making on optimal microgrid control.

Microgrid automation assisted by synchrophasors

This paper presents synchrophasor deployment for microgrid automation applications. A microgrid, which is the main component of future smart grids, requires sophisticated measurement and control capabilities. Conventional RTU based automation approaches suffer from slow measurement update and lack of time-stamp values. In this study, a time-synchronized control approach is proposed for a deployable hardware-based microgrid involving a synchronous generator and an inverter based DER. Protection event analysis, islanding detection, re-synchronization, and online remote generation unit dispatch studies are realistically demonstrated in hardware in a laboratory based test-bed.

Islanding detection using synchronized measurement in smart microgrids

This paper presents the issues involved in the detection of islanding via traditional methods as well as the implementation of 3-phase synchronized measurements. A proposed technique for better islanding recognition in microgrids using multiple PMUs was developed. A new method which uses 3 phase synchronized measurements was introduced for the detection of unbalanced or partial islanding of microgrids. This occurs when the microgrid loose only one phase of its link to the main grid. In addition to simulation of the proposed method in MATLAB/Simulink, experimental results are also obtained. A small scaled 3-phase power system at the laboratory scale was developed and used to compare the traditional and new techniques. The comparisons of experimental and simulation results show that the proposed technique was successfully verified.