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A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenTue, 16 Apr 2024 16:18:04 +0000Frequency-based load control in power systems
https://resolver.caltech.edu/CaltechCDSTR:2011.007
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Topcu-U', 'name': {'family': 'Topcu', 'given': 'Ufuk'}}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2011
Maintaining demand-supply balance and regulating frequency are key issues in power system control. Conventional approaches focus on adjusting the generation so that it follows the load. However, relying on solely regulating generation is inefficient, especially for power systems where contingencies like sudden loss in generation or sudden change in load frequently occur and the proportion of intermittent renewable power is increasing. We present a frequency-based load control scheme for demand-supply balancing and frequency regulation. We formulate a load control optimization problem which aims to balance the change in load with the change in supply while minimizing the overall end-use disutility. By studying the power system model that characterizes the frequency response to
real power imbalance between demand and supply, we design
decentralized synchronous and asynchronous algorithms which
take advantage of local frequency measurements to solve the load control problem. Case studies show that the proposed load control scheme is capable of relatively quickly balancing the power and restoring the frequency under generation-loss like contingencies or renewable power penetration. Case studies also show that the proposed scheme still works well when users have the knowledge
of a simplified system model instead of an accurate one.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/888vf-8bb79Fast Load Control with Stochastic Frequency Measurement
https://resolver.caltech.edu/CaltechCDSTR:2011.010
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Topcu-U', 'name': {'family': 'Topcu', 'given': 'Ufuk'}}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2011
Matching demand with supply and regulating frequency
are key issues in power system operations. Flexibility
and local frequency measurement capability of loads offer new regulation mechanisms through load control. We present a
frequency-based fast load control scheme which aims to match
total demand with supply while minimizing the global end-use
disutility. Local frequency measurement enables loads to make decentralized decisions on their power from the estimates of total demand-supply mismatch. To resolve the errors in such estimates caused by stochastic frequency measurement errors, loads communicate via a neighborhood area network. Case studies show that the proposed load control can balance demand with supply and restore the frequency at the timescale faster than AGC, even when the loads use a highly simplified system model in their algorithms. Moreover, we discuss the tradeoff between communication and performance, and show with experiments that a moderate amount of communication significantly improves the performance.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/95tzm-njn41Frequency-Based Load Control in Power Systems
https://resolver.caltech.edu/CaltechAUTHORS:20121003-154738717
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Topcu-U', 'name': {'family': 'Topcu', 'given': 'Ufuk'}}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2012
DOI: 10.1109/ACC.2012.6315283
Maintaining demand-supply balance and regulating frequency are key issues in power system control. Conventional approaches focus on adjusting the generation so that it follows the load. However, relying on solely regulating generation is inefficient, especially for power systems where contingencies like a sudden loss in generation or a sudden change in load frequently occur. We present a frequency-based load control scheme for demand-supply balancing and frequency regulation. We formulate a load control optimization problem which aims to balance the change in load with the change in supply while minimizing the overall end-use disutility. By studying the power system model that characterizes the frequency response to real power imbalance between demand and supply, we design decentralized synchronous and asynchronous algorithms which take advantage of local frequency measurements to solve the load control problem. Case studies show that the proposed load control scheme is capable of relatively quickly balancing the power and restoring the frequency under generation-loss like contingencies, even when users only have the knowledge of a simplified system model instead of an accurate one.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/f5xnd-c8z22Swing Dynamics as Primal-Dual Algorithm for Optimal Load Control
https://resolver.caltech.edu/CaltechCDSTR:2012.001
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Topcu-U', 'name': {'family': 'Topcu', 'given': 'Ufuk'}}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2012
Frequency regulation and generation-load balancing are key issues in power transmission networks. Complementary to generation control, loads provide flexible and fast responsive sources for frequency regulation, and local frequency measurement capability of loads offers the opportunity of decentralized control. In this paper, we propose an optimal load control problem, which balances the load reduction (or increase) with the generation shortfall (or surplus), resynchronizes the bus frequencies, and minimizes a measure of aggregate disutility of participation in such a load control. We find that, a frequency-based load control coupled with the dynamics of swing equations and branch power flows serve as a distributed primal-dual algorithm to solve the optimal load control problem and its dual. Simulation shows that the proposed mechanism can restore frequency, balance load with generation and achieve the optimum of the load control problem within several seconds after a disturbance in generation. Through simulation, we also compare the performance of optimal load control with automatic generation control (AGC), and discuss the effect of their incorporation.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/n4c7f-cfb62Swing dynamics as primal-dual algorithm for optimal load control
https://resolver.caltech.edu/CaltechAUTHORS:20130828-101518387
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Topcu-U', 'name': {'family': 'Topcu', 'given': 'Ufuk'}}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2012
DOI: 10.1109/SmartGridComm.2012.6486046
In electricity transmission networks, loads can provide flexible, fast responsive, and decentralized sources for frequency regulation and generation-demand balancing, complementary to generation control. We consider an optimal load control (OLC) problem in a transmission network, when a disturbance in generation occurs on an arbitrary subset of the buses. In OLC, the frequency-insensitive loads are reduced (or increased) in real-time in a way that balances the generation shortfall (or surplus), resynchronizes the bus frequencies, and minimizes the aggregate disutility of load control. We propose a frequency-based load control mechanism and show that the swing dynamics of the network, together with the proposed mechanism, act as a decentralized primal-dual algorithm to solve OLC. Simulation shows that the proposed mechanism can resynchronize the bus frequencies, balance demand with generation and achieve the optimum of OLC within several seconds after a disturbance in generation. Through simulation, we also compare the performance of the proposed mechanism with automatic generation control (AGC), and discuss the effect of their incorporation.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/w6w9y-cfd86Some Problems in Demand Side Management
https://resolver.caltech.edu/CaltechAUTHORS:20130815-100621563
Authors: {'items': [{'id': 'Gan-Lingwen', 'name': {'family': 'Gan', 'given': 'Lingwen'}}, {'id': 'Jiang-Libin', 'name': {'family': 'Jiang', 'given': 'Libin'}}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven'}, 'orcid': '0000-0001-6476-3048'}, {'id': 'Topcu-U', 'name': {'family': 'Topcu', 'given': 'Ufuk'}}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}]}
Year: 2012
We present a sample of problems in demand side
management in future power systems and illustrate how they
can be solved in a distributed manner using local information.
First, we consider a set of users served by a single load-serving
entity (LSE). The LSE procures capacity a day ahead. When
random renewable energy is realized at delivery time, it manages
user load through real-time demand response and purchases
balancing power on the spot market to meet the aggregate
demand. Hence optimal supply procurement by the LSE and the
consumption decisions by the users must be coordinated over two
timescales, a day ahead and in real time, in the presence of supply
uncertainty. Moreover, they must be computed jointly by the
LSE and the users since the necessary information is distributed
among them. We present distributed algorithms to maximize
expected social welfare. Instead of social welfare, the second
problem is to coordinate electric vehicle charging to fill the valleys
in aggregate electric demand profile, or track a given desired
profile. We present synchronous and asynchronous algorithms
and prove their convergence. Finally, we show how loads can
use locally measured frequency deviations to adapt in real time
their demand in response to a shortfall in supply. We design
decentralized demand response mechanism that, together with
the swing equation of the generators, jointly maximize disutility
of demand rationing, in a decentralized manner.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/a5yj9-kj319Optimal Load Control via Frequency Measurement and Neighborhood Area Communication
https://resolver.caltech.edu/CaltechAUTHORS:20131203-091918486
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Topcu-U', 'name': {'family': 'Topcu', 'given': 'Ufuk'}}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2013
DOI: 10.1109/TPWRS.2013.2261096
We propose a decentralized optimal load control scheme that provides contingency reserve in the presence of sudden generation drop. The scheme takes advantage of flexibility of frequency responsive loads and neighborhood area communication to solve an optimal load control problem that balances load and generation while minimizing end-use disutility of participating in load control. Local frequency measurements enable individual loads to estimate the total mismatch between load and generation. Neighborhood area communication helps mitigate effects of inconsistencies in the local estimates due to frequency measurement noise. Case studies show that the proposed scheme can balance load with generation and restore the frequency within seconds of time after a generation drop, even when the loads use a highly simplified power system model in their algorithms. We also investigate tradeoffs between the amount of communication and the performance of the proposed scheme through simulation-based experiments.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/wdh99-fkz82Design and Stability of Load-Side Primary Frequency Control in Power Systems
https://resolver.caltech.edu/CaltechAUTHORS:20140529-094709292
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Topcu-U', 'name': {'family': 'Topcu', 'given': 'Ufuk'}}, {'id': 'Li-Na', 'name': {'family': 'Li', 'given': 'Na'}}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2014
DOI: 10.1109/TAC.2014.2298140
We present a systematic method to design ubiquitous continuous fast-acting distributed load control for primary frequency regulation in power networks, by formulating an optimal load control (OLC) problem where the objective is to minimize the aggregate cost of tracking an operating point subject to power balance over the network. We prove that the swing dynamics and the branch power flows, coupled with frequency-based load control, serve as a distributed primal-dual algorithm to solve OLC. We establish the global asymptotic stability of a multimachine network under such type of load-side primary frequency control. These results imply that the local frequency deviations on each bus convey exactly the right information about the global power imbalance for the loads to make individual decisions that turn out to be globally optimal. Simulations confirm that the proposed algorithm can rebalance power and resynchronize bus frequencies after a disturbance with significantly improved transient performance.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/srhae-p5128Optimal load-side control for frequency regulation in smart grids
https://resolver.caltech.edu/CaltechAUTHORS:20150203-091127023
Authors: {'items': [{'id': 'Mallada-E', 'name': {'family': 'Mallada', 'given': 'Enrique'}, 'orcid': '0000-0003-1568-1833'}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2014
DOI: 10.1109/ALLERTON.2014.7028527
Frequency control rebalances supply and demand while maintaining the network state within operational margins. It is implemented using fast ramping reserves that are expensive and wasteful, and which are expected to grow with the increasing penetration of renewables. The most promising solution to this problem is the use of demand response, i.e. load participation in frequency control. Yet it is still unclear how to efficiently integrate load participation without introducing instabilities and violating operational constraints. In this paper we present a comprehensive load-side frequency control mechanism that can maintain the grid within operational constraints. Our controllers can rebalance supply and demand after disturbances, restore the frequency to its nominal value and preserve inter-area power flows. Furthermore, our controllers are distributed (unlike generation-side), can allocate load updates optimally, and can maintain line flows within thermal limits. We prove that such a distributed load-side control is globally asymptotically stable and illustrate its convergence with simulation.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/k2vxs-4nb81Optimal decentralized primary frequency control in power networks
https://resolver.caltech.edu/CaltechAUTHORS:20170123-165356940
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2014
DOI: 10.1109/CDC.2014.7039765
We augment existing generator-side primary frequency control with load-side control that are local, ubiquitous, and continuous. The mechanisms on both the generator and the load sides are decentralized in that their control decisions are functions of locally measurable frequency deviations. These local algorithms interact over the network through nonlinear power flows. We design the local frequency feedback control so that any equilibrium point of the closed-loop system is the solution to an optimization problem that minimizes the total generation cost and user disutility subject to power balance across entire network. With Lyapunov method we derive a sufficient condition for any equilibrium point of the closed-loop system to be asymptotically stable. A simulation demonstrates improvement in both the transient and steady-state performance over the traditional control only on generators, even when the total control capacity remains the same.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/5szw4-8t878Optimal Sizing of Voltage Control Devices for Distribution Circuit with Intermittent Load
https://resolver.caltech.edu/CaltechAUTHORS:20160121-102543977
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Chertkov-M', 'name': {'family': 'Chertkov', 'given': 'Michael'}}, {'id': 'Backhaus-S', 'name': {'family': 'Backhaus', 'given': 'Scott'}}]}
Year: 2015
DOI: 10.1109/HICSS.2015.323
We consider joint control of a switchable capacitor and a D-STATCOM for voltage regulation in a distribution circuit with intermittent load. The control problem is formulated as a two-timescale optimal power flow problem with chance constraints, which minimizes power loss while limiting the probability of voltage violations due to fast changes in load. The control problem forms the basis of an optimization problem which determines the sizes of the control devices by minimizing sum of the expected power loss cost and the capital cost. We develop computationally efficient heuristics to solve the optimal sizing problem and implement real-time control. Numerical experiments on a circuit with high-performance computing (HPC) load show that the proposed sizing and control schemes significantly improve the reliability of voltage regulation on the expense of only a moderate increase in cost.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/8q52c-fzz18Distributed Generator and Load-Side Secondary Frequency Control in Power Networks
https://resolver.caltech.edu/CaltechAUTHORS:20150429-072859434
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Mallada-E', 'name': {'family': 'Mallada', 'given': 'Enrique'}, 'orcid': '0000-0003-1568-1833'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2015
DOI: 10.1109/CISS.2015.7086825
We design a distributed secondary frequency control scheme for both generators and controllable loads. The proposed scheme operates via local sensing and computation, and neighborhood communication. Equilibrium and stability
analysis of the closed-loop system is performed with a power
network model including turbines and governors of generators
and nonlinear AC power flows. After a change in power supply
or demand, the proposed scheme is able to stabilize the system, restore bus frequencies and net inter-area power exchanges, and minimize total generation cost minus user utility at equilibrium.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/kpymp-a2s93Distributed frequency control for stability and economic dispatch in power networks
https://resolver.caltech.edu/CaltechAUTHORS:20150804-132940825
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Mallada-E', 'name': {'family': 'Mallada', 'given': 'Enrique'}, 'orcid': '0000-0003-1568-1833'}, {'id': 'Dörfler-F', 'name': {'family': 'Dörfler', 'given': 'Florian'}}]}
Year: 2015
DOI: 10.1109/ACC.2015.7171085
We explore two different frequency control strategies to ensure stability of power networks and achieve economic dispatch between generators and controllable loads. We first show the global asymptotic stability of a completely decentralized frequency integral control. Then we design a distributed averaging-based integral (DAI) control which operates by local frequency sensing and neighborhood communication. Equilibrium analysis shows that DAI recovers the nominal frequency with minimum total generation cost and user disutility for load control after a change in generation or load. Local asymptotic stability of DAI is established with a Lyapunov method. Simulations demonstrate improvement in both transient and steady-state performance achieved by the proposed control strategies, compared to droop control.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/zkn11-h2s67Distributed power flow loss minimization control for future grid
https://resolver.caltech.edu/CaltechAUTHORS:20150925-092242544
Authors: {'items': [{'id': 'Nakayama-Kiyoshi', 'name': {'family': 'Nakayama', 'given': 'Kiyoshi'}}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Bic-L-F', 'name': {'family': 'Bic', 'given': 'Lubomir F.'}}, {'id': 'Dillencourt-M-B', 'name': {'family': 'Dillencourt', 'given': 'Michael B.'}}, {'id': 'Brouwer-J', 'name': {'family': 'Brouwer', 'given': 'Jack'}}]}
Year: 2015
DOI: 10.1002/cta.1999
In this paper, a novel decentralized algorithm is proposed to minimize power flow loss in a large-scale future grid connecting with many real-time-distributed generation systems by which power flows bi-directionally. The DC-power loss at each link is defined as the product of resistance and the square of current that can be considered as a quadratic flow cost. We employ the notion of tie-sets that reduces the complexity of the power flow loss problem by dividing a power network into a set of loops that forms a linear vector space on which the power loss problem can be formulated as a convex optimization problem. As finding a solution in each tie-set enables global optimization, we realize parallel computing within a system of independent tie-sets by integrating autonomous agents. Simulation results demonstrate the minimization of the power loss on every link by iteratively optimized power flows and show the superiority against the traditional centralized optimization scheme.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/cbjtp-33b08Dynamic Frequency Control in Power Networks
https://resolver.caltech.edu/CaltechAUTHORS:20170712-205943130
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Mallada-E', 'name': {'family': 'Mallada Garcia', 'given': 'Enrique'}, 'orcid': '0000-0003-1568-1833'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2016
Node controllers in power distribution networks in accordance with embodiments of the invention enable dynamic frequency control. One embodiment includes a node controller comprising a network interface a processor; and a memory containing a frequency control application; and a plurality of node operating parameters describing the operating parameters of a node, where the node is selected from a group consisting of at least one generator node in a power distribution network wherein the processor is configured by the frequency control application to calculate a plurality of updated node operating parameters using a distributed process to determine the updated node operating parameter using the node operating parameters, where the distributed process controls network frequency in the power distribution network; and adjust the node operating parameters.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/dc5wm-58t35A unified framework for frequency control and congestion management
https://resolver.caltech.edu/CaltechAUTHORS:20160823-102449874
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Mallada-E', 'name': {'family': 'Mallada', 'given': 'Enrique'}, 'orcid': '0000-0003-1568-1833'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}, {'id': 'Bialek-J', 'name': {'family': 'Bialek', 'given': 'Janusz'}}]}
Year: 2016
DOI: 10.1109/PSCC.2016.7541028
The existing frequency control framework in power systems is challenged by lower inertia and more volatile power injections. We propose a new framework for frequency control and congestion management. We formulate an optimization problem that rebalances power, restores the nominal frequency, restores inter-area flows and maintains line flows below their limits in a way that minimizes the control cost. The cost can be squared deviations from the reference generations, minimizing the disruption from the last optimal dispatch. Our control thus maintains system security without interfering with the market operation. By deriving a primal-dual algorithm to solve this optimization, we design a completely decentralized primary frequency control without the need for explicit communication among the participating agents, and a distributed unified control which integrates primary and secondary frequency control and congestion management. Simulations show that the unified control not only achieves all the desired control goals in system equilibrium, but also improves the transient compared to traditional control schemes.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/9qbcj-wfm82Connecting Automatic Generation Control and Economic Dispatch From an Optimization View
https://resolver.caltech.edu/CaltechAUTHORS:20160921-122049751
Authors: {'items': [{'id': 'Li-Na', 'name': {'family': 'Li', 'given': 'Na'}}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Chen-Lijun', 'name': {'family': 'Chen', 'given': 'Lijun'}}]}
Year: 2016
DOI: 10.1109/TCNS.2015.2459451
Automatic generation control (AGC) regulates mechanical power generation in response to load changes through local measurements. Its main objective is to maintain system frequency and keep energy balanced within each control area in order to maintain the scheduled net interchanges between control areas. The scheduled interchanges as well as some other factors of AGC are determined at a slower time scale by considering a centralized economic dispatch (ED) problem among different generators. However, how to make AGC more economically efficient is less studied. In this paper, we study the connections between AGC and ED by reverse engineering AGC from an optimization view, and then we propose a distributed approach to slightly modify the conventional AGC to improve its economic efficiency by incorporating ED into the AGC automatically and dynamically.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/4cpmz-54x80Decentralized Optimal Frequency Control of Interconnected Power Systems with Transient Constraints
https://resolver.caltech.edu/CaltechAUTHORS:20170111-135813725
Authors: {'items': [{'id': 'Wang-Zhaojian', 'name': {'family': 'Wang', 'given': 'Zhaojian'}, 'orcid': '0000-0002-4998-6339'}, {'id': 'Liu-Feng', 'name': {'family': 'Liu', 'given': 'Feng'}, 'orcid': '0000-0003-2279-2558'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Mei-Shengwei', 'name': {'family': 'Mei', 'given': 'Shengwei'}, 'orcid': '0000-0002-2757-5977'}]}
Year: 2016
DOI: 10.1109/CDC.2016.7798345
We design decentralized frequency control of multi-area power systems that will re-balance power and drive frequencies to their nominal values after a disturbance. Both generators and controllable loads are utilized to achieve frequency stability while minimizing regulation cost. In contrast to recent results, the design is completely decentralized and does not require communication between areas. Our control enforces operational constraints not only in equilibrium but also during transient. Moreover, our control is capable of adapting to unknown load disturbance. We show that the closed-loop system is asymptotically stable and converges to an equilibrium that minimizes the regulation cost. We present simulation results to demonstrate the effectiveness of our design.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/0h1k9-nza14Optimal Load-side Control for Frequency Regulation in Smart Grids
https://resolver.caltech.edu/CaltechAUTHORS:20171101-115726975
Authors: {'items': [{'id': 'Mallada-E', 'name': {'family': 'Mallada', 'given': 'Enrique'}, 'orcid': '0000-0003-1568-1833'}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2017
DOI: 10.1109/TAC.2017.2713529
Frequency control rebalances supply and demand while maintaining the network state within operational margins. It is implemented using fast ramping reserves that are expensive and wasteful, and which are expected to become increasingly necessary with the current acceleration of renewable penetration. The most promising solution to this problem is the use of demand response, i.e., load participation in frequency control. Yet it is still unclear how to efficiently integrate load participation without introducing instabilities and violating operational constraints. In this paper, we present a comprehensive load-side frequency control mechanism that can maintain the grid within operational constraints. In particular, our controllers can rebalance supply and demand after disturbances, restore the frequency to its nominal value, and preserve interarea power flows. Furthermore, our controllers are distributed (unlike the currently implemented frequency control), can allocate load updates optimally, and can maintain line flows within thermal limits. We prove that such a distributed load-side control is globally asymptotically stable and robust to unknown load parameters. We illustrate its effectiveness through simulations.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/p6tpf-bzs41Profit Maximizing Planning and Control of Battery Energy Storage Systems for Primary Frequency Control
https://resolver.caltech.edu/CaltechAUTHORS:20170810-105250761
Authors: {'items': [{'id': 'Zhang-Ying-Jun', 'name': {'family': 'Zhang', 'given': 'Ying Jun'}}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Tang-Wanrong', 'name': {'family': 'Tang', 'given': 'Wanrong'}}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2018
DOI: 10.1109/TSG.2016.2562672
We consider a two-level profit-maximizing strategy, including planning and control, for battery energy storage system (BESS) owners that participate in the primary frequency control (PFC) market. Specifically, the optimal BESS control minimizes the operating cost by keeping the state of charge (SoC) in an optimal range. Through rigorous analysis, we prove that the optimal BESS control is a "state-invariant" strategy in the sense that the optimal SoC range does not vary with the state of the system. As such, the optimal control strategy can be computed offline once and for all with very low complexity. Regarding the BESS planning, we prove that the the minimum operating cost is a decreasing convex function of the BESS energy capacity. This leads to the optimal BESS sizing that strikes a balance between the capital investment and operating cost. Our work here provides a useful theoretical framework for understanding the planning and control strategies that maximize the economic benefits of BESSs in ancillary service markets.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/xjzab-d1m36Cyber Network Design for Secondary Frequency Regulation: A Spectral Approach
https://resolver.caltech.edu/CaltechAUTHORS:20180906-143422101
Authors: {'items': [{'id': 'Guo-Linqi', 'name': {'family': 'Guo', 'given': 'Linqi'}}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2018
DOI: 10.23919/PSCC.2018.8442814
We present a preliminary theoretical framework based on spectral graph theory that captures how the cyber topology of a distributed secondary frequency control scheme impacts the stability, optimality, and transient performance of our power system as a cyber-physical network. We show that a collection of polynomials defined in terms of the cyber and physical Laplacian eigenvalues encode information on the interplay between cyber and physical networks. It is demonstrated that to understand the impact of adding cyber connectivity, one should separate the low-damping and high-damping regimes. Although adding cyber connectivity always improves the performance for high-damping systems, it is not the case for low-damping scenarios. Based on the theoretical study, we discuss how a good cyber network should be designed. Our empirical study shows that for practical systems, the number of communication channels that is needed to achieve near-optimal performance is usually less than twice the number of buses.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/7cwt2-6p715Profit-Maximizing Planning and Control of Battery Energy Storage Systems for Primary Frequency Control
https://resolver.caltech.edu/CaltechAUTHORS:20190104-140522282
Authors: {'items': [{'id': 'Zhang-Angela-Yingjun', 'name': {'family': 'Zhang', 'given': 'Angela Yingjun'}}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven'}, 'orcid': '0000-0001-6476-3048'}, {'id': 'Tang-Wanrong', 'name': {'family': 'Tang', 'given': 'Wanrong'}}]}
Year: 2018
DOI: 10.1109/pesgm.2018.8586290
We consider a two-level profit-maximizing strategy, including planning and control, for battery energy storage system (BESS) owners that participate in the primary frequency control (PFC) market. Specifically, the optimal BESS control minimizes the operating cost by keeping the state of charge (SoC) in an optimal range. Through rigorous analysis, we prove that the optimal BESS control is a "state-invariant" strategy in the sense that the optimal SoC range does not vary with the state of the system. As such, the optimal control strategy can be computed offline once and for all with very low complexity. Regarding the BESS planning, we prove that the the minimum operating cost is a decreasing convex function of the BESS energy capacity. This leads to the optimal BESS sizing that strikes a balance between the capital investment and operating cost. Our work here provides a useful theoretical framework for understanding the planning and control strategies that maximize the economic benefits of BESSs in ancillary service markets.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/8fsct-8gh48Distributed Frequency Control with Operational Constraints, Part II: Network Power Balance
https://resolver.caltech.edu/CaltechAUTHORS:20190104-142158857
Authors: {'items': [{'id': 'Wang-Zhaojian', 'name': {'family': 'Wang', 'given': 'Zhaojian'}, 'orcid': '0000-0002-4998-6339'}, {'id': 'Liu-Feng', 'name': {'family': 'Liu', 'given': 'Feng'}, 'orcid': '0000-0003-2279-2558'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven'}, 'orcid': '0000-0001-6476-3048'}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Mei-Shengwei', 'name': {'family': 'Mei', 'given': 'Shengwei'}, 'orcid': '0000-0002-2757-5977'}]}
Year: 2018
DOI: 10.1109/pesgm.2018.8586037
In Part I of this paper we propose a decentralized optimal frequency control of multi-area power system with operational constraints, where the tie-line powers remain unchanged in the steady state and the power mismatch is balanced within individual control areas. In Part II of the paper, we propose a distributed controller for optimal frequency control in the network power balance case, where the power mismatch is balanced over the whole system. With the proposed controller, the tie-line powers remain within the acceptable range at equilibrium, while the regulation capacity constraints are satisfied both at equilibrium and during transient. It is revealed that the closed-loop system with the proposed controller carries out primal-dual updates with saturation for solving an associated optimization problem. To cope with discontinuous dynamics of the closed-loop system, we deploy the invariance principle for nonpathological Lyapunov function to prove its asymptotic stability. Simulation results are provided to show the effectiveness of our controller.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/2r1bj-9d227Distributed plug-and-play optimal generator and load control for power system frequency regulation
https://resolver.caltech.edu/CaltechAUTHORS:20180327-084750901
Authors: {'items': [{'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Mallada-E', 'name': {'family': 'Mallada', 'given': 'Enrique'}, 'orcid': '0000-0003-1568-1833'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}, {'id': 'Bialek-J', 'name': {'family': 'Bialek', 'given': 'Janusz'}}]}
Year: 2018
DOI: 10.1016/j.ijepes.2018.03.014
A distributed control scheme, which can be implemented on generators and controllable loads in a plug-and-play manner, is proposed for power system frequency regulation. The proposed scheme is based on local measurements, local computation, and neighborhood information exchanges over a communication network with an arbitrary (but connected) topology. In the event of a sudden change in generation or load, the proposed scheme can restore the nominal frequency and the reference inter-area power flows, while minimizing the total cost of control for participating generators and loads. Power network stability under the proposed control is proved with a relatively realistic model which includes nonlinear power flow and a generic (potentially nonlinear or high-order) turbine-governor model, and further with first- and second-order turbine-governor models as special cases. In simulations, the proposed control scheme shows a comparable performance to the existing automatic generation control (AGC) when implemented only on the generator side, and demonstrates better dynamic characteristics than AGC when each scheme is implemented on both generators and controllable loads. Simulation results also show robustness of the proposed scheme to communication link failure.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/37nnq-6dv36Graph Laplacian Spectrum and Primary Frequency Regulation
https://resolver.caltech.edu/CaltechAUTHORS:20190204-110323666
Authors: {'items': [{'id': 'Guo-Linqi', 'name': {'family': 'Guo', 'given': 'Linqi'}}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2018
DOI: 10.1109/CDC.2018.8619252
We present a framework based on spectral graph theory that captures the interplay among network topology, system inertia, and generator and load damping in determining the overall grid behavior and performance. Specifically, we show that the impact of network topology on a power system can be quantified through the network Laplacian eigenvalues, and such eigenvalues determine the grid robustness against low frequency disturbances. Moreover, we can explicitly decompose the frequency signal along scaled Laplacian eigenvectors when damping-inertia ratios are uniform across buses. The insight revealed by this framework partially explains why load-side participation in frequency regulation not only makes the system respond faster, but also helps lower the system nadir after a disturbance. Finally, by presenting a new controller specifically tailored to suppress high frequency disturbances, we demonstrate that our results can provide useful guidelines in the controller design for load-side primary frequency regulation. This improved controller is simulated on the IEEE 39-bus New England interconnection system to illustrate its robustness against high frequency oscillations compared to both the conventional droop control and a recent controller design.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/ezh7h-8fd72Distributed Frequency Control with Operational Constraints, Part II: Network Power Balance
https://resolver.caltech.edu/CaltechAUTHORS:20170726-155035857
Authors: {'items': [{'id': 'Wang-Zhaojian', 'name': {'family': 'Wang', 'given': 'Zhaojian'}, 'orcid': '0000-0002-4998-6339'}, {'id': 'Liu-Feng', 'name': {'family': 'Liu', 'given': 'Feng'}, 'orcid': '0000-0003-2279-2558'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Mei-Shengwei', 'name': {'family': 'Mei', 'given': 'Shengwei'}, 'orcid': '0000-0002-2757-5977'}]}
Year: 2019
DOI: 10.1109/TSG.2017.2731811
In Part I of this paper, we propose a decentralized optimal frequency control of multi-area power system with operational constraints, where the tie-line powers remain unchanged in the steady state and the power mismatch is balanced within individual control areas. In Part II of this paper, we propose a distributed controller for optimal frequency control in the network power balance case, where the power mismatch is balanced over the whole system. With the proposed controller, the tie-line powers remain within the acceptable range at equilibrium, while the regulation capacity constraints are satisfied both at equilibrium and during transient. It is revealed that the closed-loop system with the proposed controller carries out primal–dual updates with saturation for solving an associated optimization problem. To cope with discontinuous dynamics of the closed-loop system, we deploy the invariance principle for nonpathological Lyapunov function to prove its asymptotic stability. Simulation results are provided to show the effectiveness of our controller.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/7dpz2-fda60Distributed Frequency Control with Operational Constraints, Part I: Per-Node Power Balance
https://resolver.caltech.edu/CaltechAUTHORS:20170726-160828931
Authors: {'items': [{'id': 'Wang-Zhaojian', 'name': {'family': 'Wang', 'given': 'Zhaojian'}, 'orcid': '0000-0002-4998-6339'}, {'id': 'Liu-Feng', 'name': {'family': 'Liu', 'given': 'Feng'}, 'orcid': '0000-0003-2279-2558'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Mei-Shengwei', 'name': {'family': 'Mei', 'given': 'Shengwei'}, 'orcid': '0000-0002-2757-5977'}]}
Year: 2019
DOI: 10.1109/TSG.2017.2731810
This paper addresses the distributed optimal frequency control of multi-area power system with operational constraints, including the regulation capacity of individual control area and the power limits on tie-lines. Both generators and controllable loads are utilized to recover nominal frequencies while minimizing regulation cost. We study two control modes: 1) the per-node balance mode and 2) the network balance mode. In Part I of this paper, we only consider the per-node balance case, where we derive a completely decentralized strategy without the need for communication between control areas. It can adapt to unknown load disturbance. The tie-line powers are restored after load disturbance, while the regulation capacity constraints are satisfied both at equilibrium and during transient. We show that the closed-loop systems with the proposed control strategies carry out primal-dual updates for solving the associated centralized frequency optimization problems. We further prove the closed-loop systems are asymptotically stable and converge to the unique optimal solution of the centralized frequency optimization problems and their duals. Finally, we present simulation results to demonstrate the effectiveness of our design. In Part II of this paper, we address the network power balance case, where transmission congestions are managed continuously.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/4d9wj-z6b42Approaching Prosumer Social Optimum via Energy Sharing with Proof of Convergence
https://resolver.caltech.edu/CaltechAUTHORS:20210503-115704998
Authors: {'items': [{'id': 'Chen-Yue', 'name': {'family': 'Chen', 'given': 'Yue'}, 'orcid': '0000-0002-7594-7587'}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}, {'id': 'Mei-Shengwei', 'name': {'family': 'Mei', 'given': 'Shengwei'}, 'orcid': '0000-0002-2757-5977'}]}
Year: 2021
DOI: 10.1109/ciss50987.2021.9400276
The conventional power system operation approach has been proven to be effective and reliable for decades. Specially, at the demand side, customers are managed centrally by aggregators and usually not price-responsive. With the prevalence of distributed energy resources (DERs), traditional consumers are now endowed with the ability to produce energy, turning into so-called prosumers. Prosumers can tradeoff between supply and demand and participate in energy management proactively. At the same time, the intermittent and uncertain nature of DERs call for a stronger capability of dealing with real-time energy fluctuation. In this context, exploiting demand-side flexibility to support real-time energy balancing, which can reduce required generation reserves and save costs, is a promising direction for energy system modernization. However, the traditional centralized scheme fails to allow a prosumer to act upon its profit-maximizing philosophy, which reduces prosumer incentives and restricts demand-side flexibility. Therefore, a new prosumer-oriented approach is desired.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/wb0wr-p3f29Decentralized Provision of Renewable Predictions Within a Virtual Power Plant
https://resolver.caltech.edu/CaltechAUTHORS:20201105-145616008
Authors: {'items': [{'id': 'Chen-Yue', 'name': {'family': 'Chen', 'given': 'Yue'}, 'orcid': '0000-0002-7594-7587'}, {'id': 'Li-Tongxin', 'name': {'family': 'Li', 'given': 'Tongxin'}, 'orcid': '0000-0002-9806-8964'}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Wei-Wei', 'name': {'family': 'Wei', 'given': 'Wei'}, 'orcid': '0000-0002-1018-7708'}]}
Year: 2021
DOI: 10.1109/TPWRS.2020.3035174
The mushrooming of distributed energy resources turns end-users from passive price-takers to active market-participants. To manage massive proactive end-users efficiently, virtual power plant (VPP) as an innovative concept emerges. It can provide some necessary information to help consumers improve their profits and trade with the electricity market on behalf of them. One important information desired by consumers is the prediction of renewable outputs inside this VPP. Presently, most VPPs run in a centralized manner, which means the VPP predicts the outputs of all the renewable sources it manages and provides the predictions to every consumer who buys this information. We prove that providing predictions can boost social total surplus. However, with more consumers and renewables in the market, this centralized scheme needs extensive data communication and may jeopardize the privacy of individual stakeholders. In this paper, we propose a decentralized prediction provision algorithm in which consumers from each subregion only buy local predictions and exchange information with the VPP. Convergence is proved under a mild condition, and the demand gap between centralized and decentralized schemes is proved to have zero expectation and bounded variance. Illustrative examples show that the variance of this gap decreases with more consumers and higher uncertainty.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/dvfdb-8jr58Approaching Prosumer Social Optimum via Energy Sharing With Proof of Convergence
https://resolver.caltech.edu/CaltechAUTHORS:20210113-163505633
Authors: {'items': [{'id': 'Chen-Yue', 'name': {'family': 'Chen', 'given': 'Yue'}, 'orcid': '0000-0002-7594-7587'}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}, {'id': 'Mei-Shengwei', 'name': {'family': 'Mei', 'given': 'Shengwei'}, 'orcid': '0000-0002-2757-5977'}]}
Year: 2021
DOI: 10.1109/tsg.2020.3048402
With the advent of prosumers, the traditional centralized operation may become impracticable due to computational burden, privacy concerns, and conflicting interests. In this article, an energy sharing mechanism is proposed to accommodate prosumers' strategic decision-making on their self-production and demand in the presence of capacity constraints. Under this setting, prosumers play a generalized Nash game. We prove main properties of the game: an equilibrium exists and is partially unique; no prosumer is worse off by energy sharing and the price-of-anarchy is 1−O(1/I) where I is the number of prosumers. In particular, the PoA tends to 1 with a growing number of prosumers, meaning that the resulting total cost under the proposed energy sharing approaches social optimum. We prove that the corresponding prosumers' strategies converge to the social optimal solution as well. Finally we propose a bidding process and prove that it converges to the energy sharing equilibrium under mild conditions. Illustrative examples are provided to validate the results.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/8gdt7-0wv71An Energy Sharing Mechanism Considering Network Constraints and Market Power Limitation
https://resolver.caltech.edu/CaltechAUTHORS:20230502-727238500.2
Authors: {'items': [{'id': 'Chen-Yue', 'name': {'family': 'Chen', 'given': 'Yue'}, 'orcid': '0000-0002-7594-7587'}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}, 'orcid': '0000-0003-0539-8591'}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}, {'id': 'Wierman-A', 'name': {'family': 'Wierman', 'given': 'Adam'}, 'orcid': '0000-0002-5923-0199'}]}
Year: 2023
DOI: 10.1109/tsg.2022.3198721
As the number of prosumers with distributed energy resources (DERs) grows, the conventional centralized operation scheme may suffer from conflicting interests, privacy concerns, and incentive inadequacy. In this paper, we propose an energy sharing mechanism to address the above challenges. It takes into account network constraints and fairness among prosumers. In the proposed energy sharing market, all prosumers play a generalized Nash game. The market equilibrium is proved to have nice features in a large market or when it is a variational equilibrium. To deal with the possible market failure, inefficiency, or instability in general cases, we introduce a price regulation policy to avoid market power exploitation. The improved energy sharing mechanism with price regulation can guarantee the existence and uniqueness of a socially near-optimal market equilibrium. Some advantageous properties are proved, such as the prosumer's individual rationality, a sharing price structure similar to the locational marginal price, and the tendency towards social optimum with an increasing number of prosumers. For implementation, a practical bidding algorithm is developed with a convergence condition. Experimental results validate the theoretical outcomes and show the practicability of our model and method.https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/npwrx-d8m85Convergence of Backward/Forward Sweep for Power Flow Solution in Radial Networks
https://authors.library.caltech.edu/records/jedfs-0zx20
Authors: {'items': [{'id': 'Fang-Bohang', 'name': {'family': 'Fang', 'given': 'Bohang'}, 'orcid': '0009-0004-1055-4872'}, {'id': 'Zhao-Changhong', 'name': {'family': 'Zhao', 'given': 'Changhong'}}, {'id': 'Low-S-H', 'name': {'family': 'Low', 'given': 'Steven H.'}, 'orcid': '0000-0001-6476-3048'}]}
Year: 2023
DOI: 10.1109/cdc49753.2023.10383981
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<div>Solving power flow is perhaps the most fundamental calculation related to the steady state behavior of alternating-current (AC) power systems. The normally radial (tree) topology of a distribution network induces a spatially recursive structure in power flow equations, which enables a class of efficient solution methods called backward/forward sweep (BFS). In this paper, we revisit BFS from a new perspective, focusing on its convergence. Specifically, we describe a general formulation of BFS, interpret it as a special Gauss-Seidel algorithm, and then illustrate it in a single-phase power flow model. We prove a sufficient condition under which the BFS is a contraction mapping on a closed set of safe voltages and thus converges geometrically to a unique power flow solution. We verify the convergence condition, as well as the accuracy and computational efficiency of BFS, through numerical experiments in IEEE test systems.</div>
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</div>https://authors.library.caltech.eduhttps://authors.library.caltech.edu/records/jedfs-0zx20