Results 1  10
of
22
Optimal loadside control for frequency regulation in smart grids
"... Abstract—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 sol ..."
Abstract

Cited by 8 (3 self)
 Add to MetaCart
(Show Context)
Abstract—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 loadside 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 interarea power flows. Furthermore, our controllers are distributed (unlike generationside), can allocate load updates optimally, and can maintain line flows within thermal limits. We prove that such a distributed loadside control is globally asymptotically stable and illustrate its convergence with simulation. I.
Reverse and Forward Engineering of Frequency Control in Power Networks
"... Abstract — We reverseengineer the frequency dynamics with general primary frequency control and show that it is a distributed algorithm to solve a welldefined optimization problem. We further investigate the role of deadband in control, and show that if the aggregated uncontrolled load deviation ..."
Abstract

Cited by 6 (1 self)
 Add to MetaCart
(Show Context)
Abstract — We reverseengineer the frequency dynamics with general primary frequency control and show that it is a distributed algorithm to solve a welldefined optimization problem. We further investigate the role of deadband in control, and show that if the aggregated uncontrolled load deviation is nonzero the frequencies will be synchronized, and if however it is zero the frequencies may oscillate but within the deadband. The optimization based model does not only provide a way to characterize the equilibrium and establish the convergence of the frequency dynamics, but also suggests a principled way to engineer frequency control. By leveraging the optimization problem and insights from reverse engineering, we design a distributed realtime frequency control scheme that does not only maintain the frequency to the nominal value, but also achieve economic efficiency. This is drastically different from the current hierarchical control approach that addresses frequency regulation and economic efficiency at different timescales and with centralized control, and is what is needed for future power system to cope with rapid and large fluctuations in supply/demand and manage a huge number of control points. This work presents a step towards developing a new foundation – network dynamics as optimization algorithm – for distributed realtime control and optimization of future power networks. I.
Fair loadside control for frequency regulation in smart grids
"... Abstract—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 nonrenewable, and which are expected to grow with the increasing penetration of renewables. The most promising ..."
Abstract

Cited by 3 (2 self)
 Add to MetaCart
(Show Context)
Abstract—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 nonrenewable, 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 loadside 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 interarea power flows. Furthermore, our controllers are distributed (unlike generationside), fair among participating loads, and can further maintain line flows within thermal limits. We prove that such a distributed loadside control is globally asymptotically stable and illustrate its convergence with simulation. I.
Distributed Generator and LoadSide Secondary Frequency Control in Power Networks
"... Abstract—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 closedloop system is performed with a power netw ..."
Abstract

Cited by 1 (1 self)
 Add to MetaCart
(Show Context)
Abstract—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 closedloop 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 interarea power exchanges, and minimize total generation cost minus user utility at equilibrium. I.
A unified framework for frequency control and congestion management in lowinertia power systems
 In preparation
"... Abstract—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 frequenc ..."
Abstract

Cited by 1 (1 self)
 Add to MetaCart
(Show Context)
Abstract—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 interarea 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 primaldual 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. Index Terms—Congestion management, distributed control, frequency control, lowinertia systems. I.
Research Statement
, 2013
"... I do research in number theory and arithmetic geometry, and particularly in the area related to Galois representations and deformation of abelian varieties. It is a celebrated theorem of Serre and Tate that the deformation theory of an abelian variety A over a field of characteristic p> 0 is equi ..."
Abstract
 Add to MetaCart
(Show Context)
I do research in number theory and arithmetic geometry, and particularly in the area related to Galois representations and deformation of abelian varieties. It is a celebrated theorem of Serre and Tate that the deformation theory of an abelian variety A over a field of characteristic p> 0 is equivalent that of its BarsottiTate group. When the abelian variety A is ordinary, there is a structure of formal group on the infinitesimal deformation space of A/k, and any deformation of A is determined by the SerreTate coordinates on the deformation space ([5]). Moreover, the SerreTate deformation theory can be applied to determine the local structure of Shimura varieties of Hodge type at ordinary locus ([11],[14]). My research has been forcused on applying the SerreTate theory to two types of questions in arithmetic geometry: the first is the study of the local behavior of Galois representations attached to nearly ordinary Hilbert modular forms; the second is the study of special cases of the MumfordTate conjecture. I will give a summary of my work ([19],[20]) toward these two directions below. 1 Local behavior of Hilbert modular Galois representations Let F be a totally real field inside an algebraic closure Q ̄ of Q and let FA be the adele ring of F. Fix a rational prime p and a prime p of F over p. Let m be an integral ideal of F and Sk(m,C) be the space of Hilbert modular cusp forms of parallel weight k and level m. For each prime q of F and fractional ideal n of F prime to m, let T (q) and 〈n 〉 be the Hecke operator acting on Sk(m,C). Suppose that we have a Hilbert modular form f ∈ Sk(m,C) such that f is an eigenvector for all the above Hecke operators, i.e. there exist c(q, f), d(n, f) such that T (q)(f) = c(q, f)f and 〈n〉(f) = d(n, f)f. Let Kf be the field generated over Q by these eigenvalues c(q, f), d(n, f), which is known to be a number field. Let λ be a prime of Kf over the rational prime p and let Kf,λ be the completion of Kf at λ. Then it is well known that there is a continuous representation ρf,λ: Gal(Q̄/F) → GL2(Kf,λ) attached to f. Moreover, if f is nearly pordinary in the sense that c(p, f) ∈ Kf ⊂ Kf,λ is a padic unit, then the restriction of ρf,λ to the decomposition group Dp of Gal(Q̄/F) at p is reducible and of the following shape: ρf,λDp ∼
Digital Object Identifier: 10.1109/TSG.2015.2409053 1Consensus + Innovations Approach for Distributed MultiAgent Coordination in a Microgrid
, 2015
"... Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting / republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighte ..."
Abstract
 Add to MetaCart
(Show Context)
Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting / republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.
Distributed
"... optimization decomposition for joint economic dispatch and frequency regulation ..."
Abstract
 Add to MetaCart
optimization decomposition for joint economic dispatch and frequency regulation