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This paper proposes an effective control scheme to improve the transient behavior of VSC-based energy storage systems facing energy saturations. This control is aimed to reduce abrupt transients following energy saturations of the storage device. The WSCC 9-bus test system is used for validating and discussing the proposed controller. In particular, the dynamic response of a battery energy storage...
In this paper, a trajectory sensitivity method (TSM) is used to estimate parameters of a synchronous generator model suitable for unbalanced conditions which are typical of distribution systems. The current formulation and mechanical equations which represent the synchronous machine have parameters whose value modification cause significant changes in system's output. Trajectory sensitivity method...
A regime shift occurs when a dynamical system's state shifts from a nominal equilibrium to an alternative equilibrium. This concept is often used to describe the collapse of ecological systems, but it also appears in many engineering systems; most notably in the voltage collapse of power systems. This paper uses an information theoretic index known as the Fisher Information (FI) as a real-time statistical...
The objective of this research is to evaluate the performance of a Power System Stabilizers (PSS), designed using a formulation based on Linear Matrix Inequalities (LMIs), in an Electric Power Distribution System (EPDS) with distributed synchronous generators operating under unbalanced three-phase. Under these conditions, the steady-state operation of the EPDS is not an equilibrium point, which introduces...
This paper presents a new out-of-step detection method for multi-machine power systems based on approximate stability boundaries. The boundaries are constructed based on Zubov's method of stability analysis. The proposed out-of-step detection method first constructs a series of boundaries in power angle - frequency (δ-ω) plane, and tracks the trajectory of each generator in the δ-ω plane after the...
In this paper, we present a homotopy based numerical continuation algorithm to efficiently compute all feasible equilibria of a complex power system model. The dynamic characteristics of conventional power systems are undergoing a sea change due to the impact of large-scale integration of renewables, storage elements, new type of loads etc. Several parameters of these components affect the power system...
In this paper, a distributed multi-agent scheme is presented for reactive power management with renewable energy sources (RESs). The multi-agent system (MAS) framework is developed for distribution systems to improve the stability which is mostly dominated by voltage and the agents in this framework coordinate among themselves using online information and energy flow. In this paper, the agents basically...
This paper presents a nonlinear adaptive excitation control scheme to enhance the dynamic stability of multimachine power systems. The proposed controller is designed based on the adaptive backstepping technique where the mechanical power input to the generators and the damping coefficient of each generator are considered as unknown. These unknown quantities are estimated through the adaption laws...
In this paper, an approach is proposed to improve linear models adopted in small-signal stability studies using information extracted from measured outputs of real system, as small disturbance data recorded by phasor measurement units (PMU). With this aim, a trajectory sensitivity technique is applied on the mismatch between the output of the simulated model and the response of the real system. Using...
In this paper a recently proposed variation of the Krylov subspace method for model reduction is applied to power systems. The technique allows to easily enforce constraints on the reduced order model. Herein this is used to preserve the slow and poorly damped modes of the systems in the reduced order model. We analyze the role that these modes have in obtaining a good approximation and we show that...
Power flow solvable boundary plays an important role in contingency analysis, security assessment, and planning processes. However, to construct the real solvable boundary in multidimensional parameter space is burdensome and time consuming. In this paper, we develop a new technique to approximate the solvable boundary of distribution systems based on Banach fixed point theorem. Not only the new technique...
This paper proposes a robust control scheme to improve the integration of variable energy sources such as renewables into a DC bus distribution microgrid. The model of the controller is developed and analyzed with simplification of parameters and keeping the effect of the multiple loads and sources connected in parallel as an uncertainty. Various simulated scenarios are used to show the performance...
Analytic methods to quantify power systems stability margins while acknowledging uncertainty will be critical in dynamic security assessment due to the integration of renewable resources and uncontrollable loads. Lyapunov's direct method provides a mathematical framework to assess stability margins. However, analytical construction of Lyapunov functions are limited to very restrictive settings and...
The HVDC-AC transmission system is becoming more and more popular for its numerous benefits, such as low cost, low losses for long distance transmission, etc. However, the power oscillation of this hybrid system has become a major obstacle for its further application. Tons of methods have been tried to damp the power oscillation and static series synchronous compensator (SSSC) is proved to be one...
Most of the ongoing smart grid projects are focused on power distribution system automation and upgrades. Although there is no electricity market in the distribution system yet, this will be a natural step with increasing penetration of distributed energy resources (DER). This work extends transmission locational marginal price (LMP) concept to distribution level. A new Optimal Power Flow (OPF) methodology...
Continuation power flow is an important tool for assessing power system voltage stability. A continuation power flow method for distribution networks is proposed in view of unbalanced three-phase lines and loads in distribution networks with distributed generations (DG). The proposed method consists of tangent predictor and Newton corrector. A local geometric parameterization technique is utilized...
This paper presents an approach for dynamic state estimation of aggregated generators by introducing a new correction factor for equivalent inter-area power flows. The spread of generators from the center of inertia of each area is summarized by the correction term α on the equivalent power flow between the areas and is applied to the identification and estimation process. A nonlinear time varying...
For analysis of non-constant electro-mechanical oscillation frequency with a power system, this paper proposes an analytical approach integrating Differential Groebner Basis (Diff-GB) and the Harmonic Balance Method (HBM). This approach is illustrated in detail on a single-machine-infinite-bus system, whose oscillation frequency fluctuates with time due to its nonlinear-system nature. The Diff-GB...
In this paper, the merits of Adomian Decomposition Method (ADM) have been investigated for the time domain simulation of multi-machine power systems. ADM is an analytical approximation method for the solution of linear, nonlinear, deterministic and stochastic operator equations. It approximates the nonlinearities in the equations using Adomian polynomial series and that can form a rapidly convergent...
Droop-controlled distributed generation (DG) units are widely used in microgrids for rural electrification applications. In these microgrids, power quality is vulnerable to voltage and frequency instabilities due to limited generation capacities of DG units. More importantly, droop-controlled rotational and electronic DG units have different frequency dynamics, making a comprehensive stability analysis...
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