Generic Model of Active Distribution Network for Large Power System Stability Studies
TL;DR: In this paper, the grey-box approach was used for model development as it incorporates prior knowledge about the ADN structure into the model, making the model more physically relevant and intuitive than black-box or white-box models, and potentially improves the accuracy of the model.
Abstract: This paper presents the development of the dynamic equivalent model of an active distributed network (ADN) based on the grey-box approach. The equivalent model of an ADN comprises a converter-connected generator and a composite load model in parallel. The grey-box approach was chosen for model development as it incorporates prior knowledge about the ADN structure into the model, makes the model more physically relevant and intuitive than black-box or white-box models, and potentially improves the accuracy of the model. The dynamic equivalent model is presented in the seventh-order nonlinear state space format. It was initially loosely developed from the algebraic and differential equations describing assumed typical components of an ADN. Various static load models, dynamic load compositions, fault locations and a diverse range of distributed generation types and scenarios are considered in order to establish the generic range of model parameters for an ADN. The model is intended for the use in large power system stability studies.
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TL;DR: A thorough survey on the academic research progress and industry practices is provided, and existing issues and new trends in load modeling are highlighted.
Abstract: Load modeling has significant impact on power system studies. This paper presents a review on load modeling and identification techniques. Load models can be classified into two broad categories: 1) static and 2) dynamic models, while there are two types of approaches to identify model parameters: 1) measurement-based and 2) component-based. Load modeling has received more attention in recent years because of the renewable integration, demand-side management, and smart metering devices. However, the commonly used load models are outdated, and cannot represent emerging loads. There is a need to systematically review existing load modeling techniques and suggest future research directions to meet the increasing interests from industry and academia. In this paper, we provide a thorough survey on the academic research progress and industry practices, and highlight existing issues and new trends in load modeling.
304 citations
Cites methods from "Generic Model of Active Distributio..."
...Reference [37] presented a seventh order dynamic equivalent model using a grey-box approach....
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...gated models for the entire network using black-box [70]–[72] and grey-box [37], [38], [73] approaches....
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...microgrids (MGs) using a combination of component- and measurement-based methods [37], [38]....
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Posted Content•
TL;DR: In this paper, the authors propose a method for explicit control of the grid status, based on a common abstract model characterized by the main property of being composable, where subsystems can be aggregated into virtual devices that hide their internal complexity.
Abstract: The conventional approach for the control of distribution networks, in the presence of active generation and/or controllable loads and storage, involves a combination of both frequency and voltage regulation at different time scales. With the increased penetration of stochastic resources, distributed generation and demand response, this approach shows severe limitations in both the optimal and feasible operation of these networks, as well as in the aggregation of the network resources for upper-layer power systems. An alternative approach is to directly control the targeted grid by defining explicit and real-time setpoints for active/reactive power absorptions/injections defined by a solution of a specific optimization problem; but this quickly becomes intractable when systems get large or diverse. In this paper, we address this problem and propose a method for the explicit control of the grid status, based on a common abstract model characterized by the main property of being composable. That is to say, subsystems can be aggregated into virtual devices that hide their internal complexity. Thus the proposed method can easily cope with systems of any size or complexity. The framework is presented in this Part I, whilst in Part II we illustrate its application to a CIGR\'E low voltage benchmark microgrid. In particular, we provide implementation examples with respect to typical devices connected to distribution networks and evaluate of the performance and benefits of the proposed control framework.
79 citations
TL;DR: An updated review of most important frequency stability concerns, applied modern control strategies, and existing challenges for the integration of renewable energy sources is provided.
79 citations
TL;DR: An aggregated load model based on measurement data is formulated for dynamic simulations of large power systems, and the vector fitting method is introduced as a technique for measurement-based load modeling.
Abstract: Accurate load modeling is essential for power system stability analysis and control. This topic has regained interest, due to the high penetration of new types of loads and the increased availability of measurements in extended power grids. In this paper, an aggregated load model based on measurement data is formulated for dynamic simulations of large power systems. The proposed model employs variable-order transfer functions, enabling the accurate simulation of complex load dynamics. A complete methodology for the automatic derivation of the minimum-required model order is proposed with the model parameters calculated via a robust multisignal identification procedure. For this purpose, the vector fitting method is introduced as a technique for measurement-based load modeling. Several simulations are performed using the NEPLAN software to investigate the accuracy and the generalization capabilities of the proposed model. The model performance is thoroughly compared with other conventional load models, also using measurements recorded on a laboratory-scale microgrid.
68 citations
Cites methods from "Generic Model of Active Distributio..."
...Preprocessing is performed prior to the parameter estimation, to filter out high-frequency components, caused by harmonics and noise [31]....
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...Afterwards, for each model a generic set of parameters is obtained by computing the corresponding average value of each parameter [30], [31]....
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TL;DR: In this paper, the authors used gray-box modeling concepts to develop a static equivalent of distribution grids comprising a large number of photovoltaic (PV) systems embedded with voltage support schemes.
Abstract: High penetrations of photovoltaic (PV) systems within load pockets in distribution grids have changed pure consumers to prosumers This can cause technical challenges in distribution and transmission grids, such as overvoltage and reverse power flow Embedding voltage support schemes into PVs, such as standard ${\cos \phi (P)}$ characteristic proposed by the German grid codes, may cause more changes in the steady-state behavior of distribution grids and, in turn, the transmission side Accordingly, it is important to properly model active distribution grids to analyze the system impacts of these changes to plan and operate future smart power grids However, due to the high dimension of distribution grids, considering a detailed distribution grid to study the transmission side or a fraction of the distribution grid is either cumbersome or impractical Therefore, it is required to develop a reasonable equivalent that can fairly capture the dominant behavior of the distribution grids The aim of this paper is to use gray-box modeling concepts to develop a static equivalent of distribution grids comprising a large number of PV systems embedded with voltage support schemes In the proposed model, the PV systems are aggregated as a separate entity, and not as a negative load, which is traditionally done The results demonstrate the superior quality of the proposed model compared with the model with PV systems as the negative load
47 citations
References
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Book•
01 Jan 1994
TL;DR: In this article, the authors present a model for the power system stability problem in modern power systems based on Synchronous Machine Theory and Modelling, and a model representation of the synchronous machine representation in stability studies.
Abstract: Part I: Characteristics of Modern Power Systems. Introduction to the Power System Stability Problem. Part II: Synchronous Machine Theory and Modelling. Synchronous Machine Parameters. Synchronous Machine Representation in Stability Studies. AC Transmission. Power System Loads. Excitation in Stability Studies. Prime Mover and Energy Supply Systems. High-Voltage Direct-Current Transmission. Control of Active Power and Reactive Power. Part III: Small Signal Stability. Transient Stability. Voltage Stability. Subsynchronous Machine Representation in Stability Studies. AC Transmission. Power System Loads. Excitation in Stability Studies. Prime Mover and Energy Supply Systems, High-Voltage Direct-Current Transmission. Control of Active Power and Reactive Power. Part III: Small Signal Stability. Transient Stability. Voltage Stability. Subsynchronous Oscillations. Mid-Term and Long-Term Stability. Methods of Improving System Stability.
13,467 citations
"Generic Model of Active Distributio..." refers background or methods in this paper
...Among the variety of load models proposed in the past, the composite load model is widely used because of its physical meaning and adequate representation of a generally high proportion of induction motors in the load [13]–[16], [24]–[28]....
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...The initial parameter values for the estimation procedure are set using either typical values, or parameters from published literature [13], [17], [18], [21], [28]....
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Book•
25 Nov 2010
TL;DR: In this article, the convergence theory for inverse line search is used for line search and convergence theory of Inexact Line Search Exercises is used to define convergence conditions for unconstrained line search.
Abstract: Preface 1 Introduction 11 Introduction 12 Mathematics Foundations 121 Norm 122 Inverse and Generalized Inverse of a Matrix 123 Properties of Eigenvalues 124 Rank-One Update 125 Function and Differential 13 Convex Sets and Convex Functions 131 Convex Sets 132 Convex Functions 133 Separation and Support of Convex Sets 14 Optimality Conditions for Unconstrained Case 15 Structure of Optimization Methods Exercises 2 Line Search 21 Introduction 22 Convergence Theory for Exact Line Search 23 Section Methods 231 The Golden Section Method 232 The Fibonacci Method 24 Interpolation Method 241 Quadratic Interpolation Methods 242 Cubic Interpolation Method 25 Inexact Line Search Techniques 251 Armijo and Goldstein Rule 252 Wolfe-Powell Rule 253 Goldstein Algorithm and Wolfe-Powell Algorithm 254 Backtracking Line Search 255 Convergence Theorems of Inexact Line Search Exercises 3 Newton's Methods 31 The Steepest Descent Method 311 The Steepest Descent Method 312 Convergence of the Steepest Descent Method 313 Barzilai and Borwein Gradient Method 314 Appendix: Kantorovich Inequality 32 Newton's Method 33 Modified Newton's Method 34 Finite-Difference Newton's Method 35 Negative Curvature Direction Method 351 Gill-Murray Stable Newton's Method 352 Fiacco-McCormick Method 353 Fletcher-Freeman Method 354 Second-Order Step Rules 36 Inexact Newton's Method Exercises 4 Conjugate Gradient Method 41 Conjugate Direction Methods 42 Conjugate Gradient Method 421 Conjugate Gradient Method 422 Beale's Three-Term Conjugate Gradient Method 423 Preconditioned Conjugate Gradient Method 43 Convergence of Conjugate Gradient Methods 431 Global Convergence of Conjugate Gradient Methods 432 Convergence Rate of Conjugate Gradient Methods Exercises 5 Quasi-Newton Methods 51 Quasi-Newton Methods 511 Quasi-Newton Equation 512 Symmetric Rank-One (SR1) Update 513 DFP Update 514 BFGS Update and PSB Update 515 The Least Change Secant Update 52 The Broyden Class 53 Global Convergence of Quasi-Newton Methods 531 Global Convergence under Exact Line Search 532 Global Convergence under Inexact Line Search 54 Local Convergence of Quasi-Newton Methods 541 Superlinear Convergence of General Quasi-Newton Methods 542 Linear Convergence of General Quasi-Newton Methods 543 Local Convergence of Broyden's Rank-One Update 544 Local and Linear Convergence of DFP Method 545 Superlinear Convergence of BFGS Method 546 Superlinear Convergence of DFP Method 547 Local Convergence of Broyden's Class Methods 55 Self-Scaling Variable Metric (SSVM) Methods 551 Motivation to SSVM Method 552 Self-Scaling Variable Metric (SSVM) Method 553 Choices of the Scaling Factor 56 Sparse Quasi-Newton Methods 57 Limited Memory BFGS Method Exercises 6 Trust-Region and Conic Model Methods 61 Trust-Region Methods 611 Trust-Region Methods 612 Convergence of Trust-Region Methods 613 Solving A Trust-Region Subproblem 62 Conic Model and Collinear Scaling Algorithm 621 Conic Model 622 Generalized Quasi-Newton Equation 623 Updates that Preserve Past Information 624 Collinear Scaling BFGS Algorithm 63 Tensor Methods 631 Tensor Method for Nonlinear Equations 632 Tensor Methods for Unconstrained Optimization Exercises
837 citations
"Generic Model of Active Distributio..." refers methods in this paper
...The Levenberg-Marquardt algorithm [32] (available in Matlab System Identification Toolbox) that minimizes the sum of the squares of the vertical distances between data points and the fitted curve was used for parameter estimation as it is both fast and effective....
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Journal Article•
TL;DR: In this paper, the authors summarized the state of the art of representation of power system loads for dynamic performance analysis purposes, including definition of terminology, discussion of the importance of load modeling, important considerations for different types of loads and different kinds of analyses Typical load model data and methods for acquiring data are reviewed.
Abstract: This paper summarizes the state of the art of representation of power system loads for dynamic performance analysis purposes It includes definition of terminology, discussion of the importance of load modeling, important considerations for different types of loads and different types of analyses Typical load model data and methods for acquiring data are reviewed A list of recent references is included
749 citations
"Generic Model of Active Distributio..." refers background in this paper
...A general overview of load representation for dynamic performance analysis of the power system given in [22] and [23] includes a recommendation regarding the structure of multiple load types connected to a load bus for transient stability, longerterm dynamics and small-disturbance stability studies....
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Journal Article•
TL;DR: The goal of this paper is to promote better load modeling and advanced load modeling, and to facilitate data exchange among users of various production-grade simulation programs.
Abstract: The authors recommend standard load models for power flow and dynamic simulation programs. The goal of this paper is to promote better load modeling and advanced load modeling, and to facilitate data exchange among users of various production-grade simulation programs. Flexibility of modeling is an important consideration. For transient stability, longer-term dynamics, and small-disturbance stability programs, the authors recommend the structure of multiple load types connected to a load bus. Load types are static including discharge lighting, induction motors, synchronous motors, and transformer saturation. For each load type, multiple models may be connected to the bus. For longer-term dynamics programs, a model for LTC transformers is also recommended.
561 citations
"Generic Model of Active Distributio..." refers background in this paper
...A general overview of load representation for dynamic performance analysis of the power system given in [22] and [23] includes a recommendation regarding the structure of multiple load types connected to a load bus for transient stability, longerterm dynamics and small-disturbance stability studies....
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TL;DR: In this paper, a measurement-based composite load model is developed to model load from field measurements, and two cases are studied to illustrate the accuracy of the developed load model on describing the load dynamic characteristics in the actual power system.
Abstract: The accuracy of the load model has great effects on power system stability analysis and control. Based on our practice in China on modeling load from field measurements, this paper systematically develops a measurement-based composite load model. Principles guiding the load modeling practice are discussed based on detailed analysis on stochastic characteristics of the modeling procedure. The structure of the measurement-based composite load model is presented. A multicurve identification technique is described to derive parameters. The generalization capability of this built load model is also investigated in this paper. Two cases are studied to illustrate the accuracy of the developed load model on describing the load dynamic characteristics in the actual power system.
315 citations
"Generic Model of Active Distributio..." refers background or methods in this paper
...Among the variety of load models proposed in the past, the composite load model is widely used because of its physical meaning and adequate representation of a generally high proportion of induction motors in the load [13]–[16], [24]–[28]....
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...Further details on ZIP-IM model development and validation can be found in [14]–[16], [25], [30]....
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...The composite load model is referred to as the ZIP-IM load model [13]–[16]; 3) the mechanical torques of both generator and induction motor are assumed to be constant....
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