Power System Stability and Control

Yilu Liu

Distribution Level Synchronized Wide-Area Power Grid Measurement and Applications

The talk will introduce the research activities of power grid wide-area monitoring and some interesting observations at the DOE/NSF CURENT center and Oak Ridge National Lab. The critical roles of wide-area phasor measurement in situation awareness, operation, and control will be discussed. More specifically, this talk will demonstrate the applications of distribution level phasor measurement in automatic event alerts, oscillations alerts, islanding detection, Line trip detection, and model validation.

Vijay Vittal

Power System Stability and Control

The research in my group at Arizona State University involves various aspects of power system stability and control. In recent years the research has explored topics related to trajectory sensitivity applications, impact of increased penetration of both wind and PV solar, modeling of PV converters for positive-sequence transient stability analysis, developing distribution level load models using power system measurements, integrated adequacy and dynamic security assessment for power system reliability and more recently examining the interdependency between electricity and water systems.

Gurunath Gurrala

An Online Power System Stability Monitoring System Using Convolutional Neural Networks

A continuous Online Monitoring System (OMS) for power system stability based on Phasor Measurements (PMU measurements) at all the generator buses will be presented in this talk. Unlike the state-of-the-art methods, the proposed OMS does not require information about fault clearance. We propose a convolutional neural network, whose input is the heatmap representation of the measurements, for instability prediction. Through extensive simulations on standard IEEE 118-bus and IEEE 145-bus systems, the effectiveness of the proposed OMS is demonstrated under varying loading conditions, fault scenarios, topology changes and generator parameter variations. Two different methods are also proposed to identify the set of critical generators which are most impacted in the unstable cases.

Dheeman Chatterjee

Maintaining stable operation of a large interconnected power system becomes difficult with the increase in penetration of variable sources like wind and solar. Moreover, the integration of these sources through power electronics (and also installation of HVDC lines) may mean no inertia accompanying the power sources. On the positive side, introduction of phasor measurement units (PMU) provides the capability of monitoring the system variables in real time. This presentation discusses the possibility of utilizing the information from PMUs to first arrive at some metric to assess global stability and subsequently to generate some control action to maintain stable operation. The same converters associated with the renewables, HVDC and Flexible AC Transmission Systems (FACTS) may be utilized as fast acting actuators to implement the required control. The concept is demonstrated in this work/presentation through a series FACTS device, TCSC, whose firing angles are decided on the basis of energy functions computed using PMU data. The objective of the control is to bring the system to a stable equilibrium point through the shortest trajectory. The delay associated with the PMU and communication is also taken care of while formulating the control. At the end, the possibility of implementing similar action through wind generator converters is also discussed.

Microgrids

Prabodh Bajpai

Hybrid AC-DC Microgrid system

The War of Currents (AC & DC) that started almost a century ago, is still not over, However, initially the war was about the existence of AC or DC and now it is for the coexistence of AC and DC. I t looks like the two currents will end up working parallel to each other in a sort of hybrid armistice. T his talk will give an overview about a unique hybrid (AC-DC) microgrid system being developed at IIT Kharagpur. The challanges and experience in the design, components, operation, real time control, communication and application of this hybrid microgrid system will be presented in this talk.

Sairaj Dhople

Decentralized Nonlinear Controllers for AC and DC Microgrids

This talk presents decentralized nonlinear controllers for paralleled power-electronics converters in AC and DC microgrids. Feedback strategies are developed by leveraging insights from phase-synchronized and phase-balanced motions of Van der Pol oscillator circuits in complex electrical networks. The main result that will be presented in this talk is how the signs of the local feedback gains determine the stability of either phase-synchronized or phase-balanced trajectories of interconnected Van der Pol oscillator circuits. Synchronized solutions are of interest in parallel-connected dc-ac inverters and phase-balanced solutions are of interest in interleaving switching waveforms for multiphase dc-dc converters. To the best of our knowledge, fully decentralized strategies for switch interleaving in paralleled dc-dc converters have not been proposed in the literature. Similarly, our synchronization strategy for inverters offers improved time-domain performance compared to state-of-the-art droop control methods.

Wide Area Monitoring and Control

Aranya Chakrabortty

Wide-Area Control using Reinforcement Learning, but in Severely Reduced Dimension

Reinforcement Learning (RL) is an effective way of designing model-free linear quadratic regulator (LQR) controller for linear time-invariant (LTI) networks with unknown state-space models. However, when the network size is large, conventional RL can result in unacceptably long learning times. In this talk I will present a brief overview of how we can resolve this problem by developing an alternative approach that combines dimensionality reduction with RL theory. The approach is to construct a compressed state vector by projecting the measured state through a projective matrix, which is constructed offline using probing signals. This matrix can be viewed as an empirical controllability gramian that captures the level of redundancy in the open-loop network model. Next, a RL-controller is learned using the compressed state instead of the original state such that the resultant cost is close to the optimal LQR cost. The talk will end by highlighting the potential use of this method, with associated benefits and challenges, for wide-area control of power systems.

Le Xie

Streaming Analytics for the Future Grid

How to conduct real-time analytics of streaming measurement data in the power grid? This talk offers a dynamic systems approach to utilizing data of different time scale for improved monitoring of the grid cyber and physical security. This talk presents how to leverage synchrophasor data dimensionality reduction and Robust Principal Component Analysis for early anomaly detection, visualization, and localization. The underlying theme of the work suggests the importance of integrating data with dynamic context-aware models in the smart grid.

Anurag K Srivastava

Enabling Resilient Electric Grid

Keeping the power on especially to the critical facilities such as hospitals and fire department during extreme adverse operating scenarios is essential. Recent events such as Ukraine attack and Hurricane Maria in the Puerto Rico has exposed the vulnerabilities of the electric grid against extreme events. There is a need for a flexible and resilient grid to minimize the impact of component failures given adverse events. Availability of data from massive sensors deployment enables new monitoring and control strategies such as early alarm and diagnosis, predicative analysis, distributed and decentralized control, flexible and adaptive control. Phasor measurement units (PMUs) provide enhanced situational awareness and decision support in transmission systems. Distribution automation and smart meters enables advanced visibility of distribution network. Big data is generated and monitored ubiquitously in smart grids, but largely unexploited in discovering knowledge and new solutions for critical power grid applications. Robust data analytics solutions including data science and machine learning are critical towards the optimized operation to enhance the resiliency of the smart grid. Availability of additional sensor data brings its own challenges including data anomalies, real time processing and cyber-security management. This presentation will focus on enabling resiliency by utilizing sensor data, real time data analytics and advanced tools to propose ‘Siri/Alexa for the power grid’ to enhance situational awareness and decision support in the power grid control center.

Electricity Markets and Regulation

Kenko Uchida

Incentive Design for Dynamic Energy Supply-Demand Networks

Toward more stable and efficient energy supply-demand systems, well-functioning and transparent energy market mechanisms are sought. We consider a market model for energy supply-demand networks, which is described as a multi-objective game model with principal(public utility and auctioneer) and agents (prosumers), where we say that the market is cleared when the game has an optimum solution. Using this model, we discuss the role of incentive in the energy markets from the viewpoint of mechanism theory, and report our recent trials to establish the new market models by incentive design for dynamic supply-demand networks.

Siddharth Suryanarayanan

Quantifying the Impact of Solar Photovoltaic and Energy Storage Assets on the Performance of a Residential Energy Aggregator

Demand response (DR) and renewable energy sources have opened new avenues for end-users to lower their energy expenses via energy management systems. Aggregators facilitate the participation of end-users by acting on their behalf and interacting with bulk electricity markets. In this talk, an energy management algorithm is presented to investigate the impact of distributed photovoltaic (PV) and central energy storage system (ESS) assets on the economic performance of an energy aggregator in the residential sector. To enable DR, the aggregator provides a competitive incentive price to end-users, and centrally optimizes the central ESS assets and schedule of committed customer elastic loads. Thus, customers reduce their daily electricity bill while the aggregator decreases the aggregated peak consumption and earns profits as a return for providing DR services. The scope of this talk pertains to the economic impact of distributed PV and central ESS assets on aggregator profits and customer savings resulting from DR, including ESS degradation. Simulation results showed that the central ESS increases the income of the aggregator, while residential PV reduces the impact of DR. This work is a collaborative effort of researchers from Colorado State University and South Dakota State University under NSF awards ECCS-1608722 and ECCS-1608898. International collaborations include Université Bourgogne Franche-Comté (UBFC), and Université de Toulouse in France. This work is accepted for publication in the IEEE Transactions on Sustainable Energy (Dec. 2018).

Abhijit R Abhyankar

Ancillary Service Market for Energy Storage Systems (ESS)

Predicting and maintaining schedules of uncertain and variable renewable energy sources is a challenging task. These tasks can be bettered with the help of Energy Storage Systems (ESS) in tandem with renewable generation. Along with stabilising renewable schedule, ESS can serve as fast ramp reserve. Recent Regulatory orders acknowledge fast ramp performance of ESS. Because of this, there will be reduction in reserve capacity requirement for conventional generators and the overall cost of operation would be reduced. This will also have bearing on system flexibility. In this light, there is a tremendous potential for developing a market mechanism for trading of products associated with ESSs. It is expected that a large number of entities would get involved provided appropriate market design is in place. This would foster the growth of ESS in the system. This short talk would briefly touch upon various issues pertaining to market design and operational issues like optimal sequencing of reserves in the presence of ESSs as ancillary services.

Renewable Integration: Challenges and Solutions

Sandeep Anand

Recent Trends and Challenges in Solar Inverters

Solar Photovoltaics (PV) is one of the fastest growing renewable energy resources, which is being integrated into distribution systems worldwide due to its easy installation and cost competitiveness. Inverters play an important role in extracting, processing and feeding the power to the grid. Over the last decade, various interesting topologies and control methods have led to improvements in its performance. With increasing penetration of solar PV in distribution system, new challenges such as reliability, extraction efficiency, voltage regulation, power quality etc. are gaining importance. This presentation would focus on the recent advancements in solar PV string inverters. Topics related to circuit topologies, and control of inverters to meet the future grid codes would be discussed. Reliability and health monitoring of various components of Inverter would be introduced as potential areas for future research. The solutions to some of these problems, found at Power Electronics for Renewable Integration (PERI) Lab, at Indian Institute of Technology (IIT) Kanpur, India, would be presented. Joint projects carried out with the participation of various Industries in this area, would also be discussed.

Chanan Singh

Integration of Intermittent renewable resources – grid relibility issues and solutions

The objective of wind and solar energy exploitation is for economical, sustainable and environmentally friendly replacement of conventional energy sources. However, such ambitions suppose large-scale deployments of wind turbines and solar installations in order to significantly affect national economies. Many developed countries are already engaged in policies privileging high penetration of such resources, setting objectives to be achieved in the decades to come.

Wind and solar are both intermittent in nature, have power electronics interface and alter the inertia in the system. They have implications for the reliability of power systems – both adequacy and stability. This presentation will discuss the issues involved in modeling the impact of these resources and potential ways to mitigate the effects of variability of resources such as wind and solar.

Junichi Imura

HARPS Challenges to Big-PV Power System Control

This talk presents a series of results obtained by the HARPS project, whose purpose is to develop a system theory of harmonized power system control under a large penetration of photovoltaic (PV) power systems. First, a power system structure to achieve harmonized balancing is proposed from the systematic points of view. Next, based on this structure, various research topics developed in our project, i.e., PV power prediction, supply and demand control based on machine learning, pseudo-synchronous power PCS, and advanced PSS, are presented.

Takashi Nakajima

Improvement of Terrestrial Science Data Availability and Development of the Energy Demand Models for an Energy Management System

Utilization of the renewable energy had been increased in these years for the global scale. It is needed a energy management system that allows big amount of renewable energy input. Factors to be studied are, (1) meteorology, (2) energy supply systems, and (3) energy demands. However, monitoring and modeling of meteorology and energy demand are not sufficient. For instance, it is needed to understand the current status, short term prediction, and uncertainty of the solar energy, because the solar irradiance varies temporally and spatially. Also, it is needed to understand elements and variables of energy demand, then need modeling of demand and load curve, because energy demand varies temporally due to many kinds of factors. In this presentation, we are going to show current status and prediction of solar energy estimation using the 3rd generation geostationary satellite, and going to show energy demand simulation results for residential buildings.

Nilanjan Senroy

Grid Flexibility for Incoming Wind Power Generation

In this lecture, I will focus on the impact of incoming wind energy conversion systems on the operational stability of power networks. I will look at rotor angle, voltage and frequency stability aspects.

Smart Buildings, Communities, and Cities

Tatsuya Suzuki

Charging Management of EV for Smart City

(TBA)

Yu Fujimoto

Urban-Scale Distributed Energy Management Systems Evaluation Platform Towards Realization of Smart City

Distributed introduction of various energy management system (EMS) technologies will play a key role in realization of a sustainable low-carbon society. We have focused on to develop a highly versatile evaluation platform for distributed EMS methodologies; it provides a quantitative analysis scheme for wide variety of issues of smart cities which involve smart consumers with EMSs, such as BEMS (Building EMS) and HEMS (Home EMS), as well as photovoltaic solar systems, electric vehicles and so forth on the distribution networks. In this presentation, we introduce several examples of utilizing our evaluation platform of distributed EMSs and a demonstration experiment in real cities currently being conducted conducted on the basis of the evaluation result.

Distribution Network Management

Anamika Dubey

Control and Operation of Large-Scale Power Distribution Systems

With the integration of alternative energy (wind and solar) sources, the U.S. power grid faces challenges due to uncertain demand and supply imbalances, requiring methods to coordinate their operation. Currently, my group is developing centralized and decentralized control algorithms at the distribution level to coordinate the operation of non-traditional loads and generation for a large-scale multi-phase unbalanced power distribution system. This is achieved by (1) developing centralized methods to empower distribution system operators to extract and aggregate flexibility from residential customers and (2) using bilateral coordination framework to enable the participating entities in making decisions regarding supply or consumption based on signals from transactive neighbors. Future directions include incorporating autonomous machine learning-based decision-making constructs to supplement model-based optimal power flow/control methods.

Johanna Mathieu

Network-aware cost-effective coordination of distributed energy resources

In this talk I will describe my work to develop strategies to coordinate distributed energy resources to provide a variety of services to power systems. My research seeks to develop practical and cost-effective ways to leverage existing resources such as flexible loads and distributed storage to improve power system reliability, economics, and environmental impact. To this end, I use tools from control, optimization, estimation, and learning. I am currently focused on developing load coordination strategies that mitigate distribution network constraint violations and distributed storage coordination strategies that maximize the value of storage aggregations across multiple simultaneous services.

Zhihua Qu

Resilient and Distributed Voltage Control for High Penetration DERs

The increasing penetration of DERs in distribution networks and their power injection variations present new challenges of power system operation and control. In this talk, we will examine high-penetration scenarios of DER integration and their control issues. Then, the corresponding optimization and control problems are formulated, the solutions are presented, and implementation constraints are discussed. Additionally, the critical issue of how to make distributed optimization and control resilient to cyber and physical attacks is examined. A new open-source software platform, multi-agent OpenDSS, will be outlined, and it is specifically developed for the study and verification of self-organizing distribution networks and their robust distributed control regimes.

Power Grids: Cyber-Physical Systems

Quanyan Zhu

Meta-Game Approach to Cross-Layer Cyber Defense and Resilient Control Design for Power Systems

This talk aims to introduce a cross-layer design paradigm for secure, robust and resilient cyber-physical energy systems. We establish a game-of-games framework for the large-scale energy systems that includes the cyber and physical components. For the cyber layer, we use a game-theoretic model to capture the strategic behaviors of the network defender and the cyber attacker and compute its mixed strategy Nash equilibria. For the physical layer, we design a robust and resilient switching controller using a Markov jump linear system model. Due to the interdependence between the cyber and physical systems, their performances are coupled and designed in a holistic manner. Case studies are provided to illustrate the interdependent design principles of cyber-physical energy systems.

Manimaran Govindarasu

PowerCyber: A CPS Security Testbed for Smart Grid and Its Use-cases

Modern power grid is a complex Cyber Physical System (CPS) that forms the lifeline of our society. In recent years, there has been a growing trend both in number and the sophistication of cyber-attacks targeting the grid infrastructures around the globe. For instance, the two cyber-attacks targeting Ukrainian power grid in 2015 and 2016 underscore the urgency and importance of addressing this growing issue. To gain deeper insights into such real attacks and to have effective plan to deal with emerging stealthy attacks require realistic testbed environments, wherein plausible attack-defense scenarios can be tested and validated, and the security solutions can be evaluated. In addition, testbeds also provide an ideal platform for testing and validation of security solutions before being deployed into real power grid environments. This talk briefly presents a holistic framework for CPS security for the power grid. Then, it presents our experience in the design and implementation of a CPS security testbed, called PowerCyber, which exhibits an adequate level of scalability, CPS fidelity, and remote accessibility. Then, the talk concludes illustrating a few use-cases of the testbed in cybersecurity research, education, and industry outreach.

Sarasij Das

Steganography based Low Complexity Authentication Scheme for Synchrophasor Communication

Successful cyber-attack on synchrophasor network can have devastating impacts on the power grids. One of the limitations of the IEEE standard C37.118-2 is that it does not address the security requirements of synchrophasor communications. In the IEEE standard C37.118-2, Cyclic Redundancy Check (CRC) has been proposed for validating synchrophasor data and does not specify any form of authentication between communicating devices. Commonly, cryptography is used for message authentication. However, cryptography based authentication schemes are often computationally demanding and are not preferred for synchrophasor communication where resources are not available to perform high computations. To address this limitation, this paper proposes a steganography based low complexity scheme for authentication of synchrophasor data. Real time data transfer between Phasor Measurement Units (PMUs) and Phasor Data Concentrator (PDC) instances has shown that with increase in the number of bytes, the proposed scheme performs better than the existing standard hashing functions.