TY - CONF
T1 - Batch Measurement Extremum Seeking Control of Distributed Energy Resources to Account for Communication Delays and Information Loss
T2 - Hawaii International Conference on System SciencesProceedings of the 53rd Hawaii International Conference on System Sciences
Y1 - 2020/01//
A1 - Michael D. Sankur
A1 - Maxime Baudette
A1 - Jason S. MacDonald
A1 - Daniel B. Arnold
AB - Distributed Energy Resources (DER) have great potential to enhance the operation of electric power distribution systems. Previously, we explored the use of 2 Dimensional Extremum Seeking (2D-ES) control algorithms to enable model-free optimal control of DER to provide grid services to both the distribution and transmissions systems. Motivated by preliminary deployments of DER managed by 2D-ES algorithms in hardware-in-the-loop tests and in operational distribution grids, in this work, we extend the control scheme to accommodate communication delays and information loss.We propose a modification to the 2D-ES scheme to allow for the processing of batches of possibly noncontiguous objective function measurements at unknown and possibly uneven intervals. We provide a proof of the convergence of the batch 2D-ES (2D-BES) scheme when optimizing a generic convex objective function, as well as simulation results that demonstrate the suitability of the approach for substation active and reactive power target tracking.
JF - Hawaii International Conference on System SciencesProceedings of the 53rd Hawaii International Conference on System Sciences
PB - Hawaii International Conference on System Sciences
ER -
TY - JOUR
T1 - Learning Behavior of Distribution System Discrete Control Devices for Cyber-Physical Security
JF - IEEE Transactions on Smart Grid
Y1 - 2020/01//
SP - 749
EP - 761
A1 - Ciaran Roberts
A1 - Anna Scaglione
A1 - Mahdi Jamei
A1 - Reinhard Gentz
A1 - Sean Peisert
A1 - Emma M. Stewart
A1 - Chuck McParland
A1 - Alex McEachern
A1 - Daniel B. Arnold
AB - Conventional cyber-security intrusion detection systems monitor network traffic for malicious activity and indications that an adversary has gained access to the system. The approach discussed here expands the idea of a traditional intrusion detection system within electrical power systems, specifically power distribution networks, by monitoring the physical behavior of the grid. This is achieved through the use of high-rate distribution Phasor Measurement Units (PMUs), alongside SCADA packets analysis, for the purpose of monitoring the behavior of discrete control devices. In this work we present a set of algorithms for passively learning the control logic of voltage regulators and switched capacitor banks. Upon detection of an abnormal operation, the operator is alerted and further action can be taken. The proposed learning algorithms are validated on both simulated data and on measured PMU data from a utility pilot deployment site.
VL - 11
IS - 1
JO - IEEE Trans. Smart Grid
ER -
TY - JOUR
T1 - Linear Single- and Three-Phase Voltage Forecasting and Bayesian State Estimation With Limited Sensing
JF - IEEE Transactions on Power Systems
Y1 - 2019/11//
SP - 1674
EP - 1683
A1 - Roel Dobbe
A1 - Werner van Westering
A1 - Stephan Liu
A1 - Daniel B. Arnold
A1 - Duncan S. Callaway
A1 - Claire Tomlin
AB - Implementing state estimation in low and mediumvoltage power distribution is still challenging given the scale of many networks and the reliance of traditional methods on a large number of measurements. This paper proposes a method to improve voltage predictions in real-time by leveraging a limited set of real-time measurements. The method relies on Bayesian estimation formulated as a linear least squares estimation problem, which resembles the classical weighted least-squares (WLS) approach for scenarios where full network observability is not available. We build on recently developed linear approximations for unbalanced three-phase power flow to construct voltage predictions as a linear mapping of load predictions constructed with Gaussian processes. The estimation step to update the voltage forecasts in real-time is a linear computation allowing fast high-resolution state estimate updates. The uncertainty in forecasts can be determined a priori and smoothed a posteriori, making the method useful for both planning, operation and post-hoc analysis. The method outperforms conventional WLS and is applied to different test feeders and validated on a real test feeder with the utility Alliander in The Netherlands.
VL - 35
IS - 3
JO - IEEE Trans. Power Syst.
ER -
TY - JOUR
T1 - Lossy DistFlow Formulation for Single and Multiphase Radial Feeders
JF - IEEE Transactions on Power Systems
Y1 - 2019/11//
SP - 1758
EP - 1768
A1 - Eran Schweitzer
A1 - Shammya Saha
A1 - Anna Scaglione
A1 - Nathan G. Johnson
A1 - Daniel B. Arnold
AB - A line loss approximation via parametrization is developed to improve performance of the simplified Baran and Wu DistFlow method, while maintaining a linear set of equations. The approach is evaluated on thousands of training feeders that are created to determine a numerically optimal setting for the parameterization. Feeders are generated using recent advances in synthetic network test case generation. The problem is formulated with the same structure as the simplified DistFlow, yet is more accurate given that line losses are explicitly expressed and quantified. The single-phase methodology is extended to multiphase systems by formulating matrix-vector equations that maintain an analogy to their single-phase counterpart. Results with approximated line losses are shown to also improve the accuracy of multiphase distribution system calculations.
VL - 35
IS - 3
JO - IEEE Trans. Power Syst.
ER -
TY - JOUR
T1 - Model-Free Optimal Voltage Phasor Regulation in Unbalanced Distribution Systems
JF - IEEE Transactions on Smart Grid
Y1 - 2020/01//
SP - 884
EP - 894
A1 - Michael D. Sankur
A1 - Roel Dobbe
A1 - Alexandra von Meier
A1 - Daniel B. Arnold
AB - The proliferation of voltage Phasor Measurement Units (PMUs) into electric power distribution grids presents new opportunities for utility operators to manage their systems more effectively. In particular, distribution-level PMUs can serve as proxy measurements for active and reactive power flows, thus alleviating the need for current transformer-based measurements for certain applications. In this work, we explore the use of distribution PMU measurements to optimally control line power flows without explicit measurements of these quantities and without a priori knowledge of the underlying distribution system topology. To do so, we extend a 2 dimensional Extremum Seeking (2D-ES) control paradigm to simultaneously manage Distributed Energy Resource (DER) active and reactive power contributions in unbalanced distribution systems. Simulation results show the ability of the proposed approach to virtually island different portions of a 3-phase unbalanced the network using DER injections while maintaining proper voltage magnitudes in the rest of the network.
VL - 11
IS - 1
JO - IEEE Trans. Smart Grid
ER -
TY - JOUR
T1 - Toward Distributed Energy Services: Decentralizing Optimal Power Flow With Machine Learning
JF - IEEE Transactions on Smart Grid
Y1 - 2020/03//
SP - 1296
EP - 1306
A1 - Roel Dobbe
A1 - Oscar Sondermeijer
A1 - David Fridovich-Keil
A1 - Daniel B. Arnold
A1 - Duncan S. Callaway
A1 - Claire Tomlin
AB - The implementation of optimal power flow (OPF) methods to perform voltage and power flow regulation in electric networks is generally believed to require extensive communication. We consider distribution systems with multiple controllable Distributed Energy Resources (DERs) and present a data-driven approach to learn control policies for each DER to reconstruct and mimic the solution to a centralized OPF problem from solely locally available information. Collectively, all local controllers closely match the centralized OPF solution, providing near-optimal performance and satisfaction of system constraints. A rate distortion framework enables the analysis of how well the resulting fully decentralized control policies are able to reconstruct the OPF solution. The methodology provides a natural extension to decide what nodes a DER should communicate with to improve the reconstruction of its individual policy. The method is applied on both single- and three-phase test feeder networks using data from real loads and distributed generators, focusing on DERs that do not exhibit intertemporal dependencies. It provides a framework for Distribution System Operators to efficiently plan and operate the contributions of DERs to achieve Distributed Energy Services in distribution networks.
VL - 11
IS - 2
JO - IEEE Trans. Smart Grid
ER -
TY - JOUR
T1 - Distribution Voltage Regulation Using Extremum Seeking Control With Power Hardware-in-the-Loop
JF - IEEE Journal of Photovoltaics
Y1 - 2018/10//
SP - 1824
EP - 1832
A1 - Jay Johnson
A1 - Adam Summers
A1 - Rachid Darbali-Zamora
A1 - Javier Hernandez-Alvidrez
A1 - Jimmy Quiroz
A1 - Daniel B. Arnold
A1 - Jithendar Anandan
AB - Interoperable distributed energy resources (DER), including photovoltaic (PV) inverters, are capable of providing a number of grid services by receiving commands from grid operators, aggregators, or other third parties. In many control scenarios, the grid operator must determine the operating mode and parameters for the devices to achieve a specific control objective. In this paper, we experimentally validate a distributed technique to achieve optimal DER reactive power operating points for distribution circuit voltage regulation using extremum seeking control. The method is demonstrated with physical and virtual DER connected to multiple hardware-in-the-loop distribution circuit simulations. This paper demonstrates PV inverters with realistic communication interfaces can receive real-time control signals from an aggregator and adjusting their reactive power to minimize voltage deviations. Simulations were conducted with fixed and variable solar irradiance to demonstrate the robustness of the approach.
VL - 8
IS - 6
JO - IEEE J. Photovoltaics
ER -
TY - JOUR
T1 - Model-Free Optimal Coordination of Distributed Energy Resources for Provisioning Transmission-Level Services
JF - IEEE Transactions on Power Systems
Y1 - 2017/05//
SP - 817
EP - 828
A1 - Daniel B. Arnold
A1 - Michael D. Sankur
A1 - Matias Negrete-Pincetic
A1 - Duncan S. Callaway
AB - Collective control of distributed energy resources (DER)-such as photovoltaic (PV) inverters or battery storage-have the potential to provide regulation services to the bulk electric grid. While optimal power flow techniques may be used to coordinate DER for this purpose, these approaches typically rely on accurate network models and a large number of system measurements. In this paper, we consider an approach that alleviates these modeling and measurement requirements. Here, we consider a two-dimensional adaptive control scheme known as extremum seeking, or ES, to perform optimization without knowledge of a model of the distribution network. We apply this scheme to enable simultaneous feeder head active power and voltage magnitude reference tracking, as well as feeder voltage regulation. From the perspective of the transmission grid, this approach essentially transforms the distribution feeder into a controllable (P,V) bus. Simulation results confirm the ability of the approach to track substation real power and voltage reference signals while maintaining distribution system voltages within acceptable tolerances.
VL - 33
IS - 1
JO - IEEE Trans. Power Syst.
ER -
TY - CONF
T1 - Accuracy and Validation of Measured and Modeled Data for Distributed PV Interconnection and Control
T2 - 2015 IEEE PES GM
Y1 - 2015/07//
A1 - Emma M. Stewart
A1 - Sila Kiliccote
A1 - Daniel B. Arnold
A1 - Alexandra von Meier
A1 - Reza Arghandeh
AB - The distribution grid is changing to become an active resource with complex modeling needs. The new active distribution grid will, within the next ten years, contain a complex mix of load, generation, storage and automated resources all operating with different objectives on different time scales from each other and requiring detailed analysis. Electrical analysis tools that are used to perform capacity and stability studies have been used for transmission system planning for many years. In these tools, the distribution grid was considered a load and its details and physical components were not modeled. The increase in measured data sources can be utilized for better modeling, but also control of distributed energy resources (DER). The utilization of these sources and advanced modeling tools will require data management, and knowledgeable users. Each of these measurement and modeling devices have accuracy constraints, which will ultimately define their future ability to be planned and controlled. This paper discusses the importance of measured data accuracy for inverter control, interconnection and planning tools and proposes ranges of control accuracy needed to satisfy all concerns based on the present grid infrastructure.
JF - 2015 IEEE PES GM
CY - Denver, CO
U2 - LBNL-187870
ER -
TY - CONF
T1 - Extremum Seeking Control of Smart Inverters for VAR Compensation
T2 - Power & Energy Society General Meeting, IEEE
Y1 - 2015/09//
A1 - Daniel B. Arnold
A1 - Matias Negrete-Pincetic
A1 - Emma M. Stewart
A1 - David M. Auslander
A1 - Duncan S. Callaway
AB - Reactive power compensation is used by utilities to ensure customer voltages are within pre-deﬁned tolerances and reduce system resistive losses. While much attention has been paid to model-based control algorithms for reactive power support and Volt Var Optimization (VVO), these strategies typically require relatively large communications capabilities and accurate models. In this work, a non-model-based control strategy for smart inverters is considered for VAR compensation. An Extremum Seeking control algorithm is applied to modulate the reactive power output of inverters based on real power information from the feeder substation, without an explicit feeder model. Simulation results using utility demand information conﬁrm the ability of the control algorithm to inject VARs to minimize feeder head real power consumption. In addition, we show that the algorithm is capable of improving feeder voltage proﬁles and reducing reactive power supplied by the distribution substation.
JF - Power & Energy Society General Meeting, IEEE
U2 - LBNL-1003974
ER -