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After completion and operation of UHVDC, influence on stability of interconnected power grid is studied from multiple aspects. To cope with the DC block fault occurred in UHVDC transmission line, the coordinated control strategy based on emergency DC power supply is researched, by which the total amount of load shedding and generator tripping can be reduced. According to the comparison and selection...
A new approach to designing a microgrid supervisory controller based on a hybrid automaton is described. A microgrid is defined as a small-scale local grid, comprised of various distributed energy resources (DERs), loads, and energy storage systems. Due to the intermittency of renewable generation, microgrid controllers play a vital role maintaining microgrid stability and integrity in case of an...
This paper investigates the most suitable location to place variable-speed wind generator based wind farms in a power system considering the steady-state voltage stability. The doubly-fed induction generator (DFIG) and the full-converter wind generator (FCWG) based wind generation is considered and the inherent reactive power capability of these generators are accurately represented in the study....
Methods to modify power system dynamics through the addition of synthetic inertia have gained increasing research attention over the past several years. Many researchers justify this focus by implicitly assuming that adding inertia increases a system's stability, and only focusing on the frequency nadir as a measure of performance. In this paper, we draw attention to the fact that adding synthetic...
The question of studying the distributed generation systems stability is relevant due to several factors. These are: the constant load level and environment change and, accordingly, the change of generators parameters that make up this system. In the article, the stability of distributed generation system consisting of the two generators, one of which operates a current source mode is considered....
Transient analysis plays an important role in power system. As far as the stability of a plant is concerned, transient stability is very critical for small power plants. Transient analysis is aimed at determining whether a system will remain in synchronism with other generating plants after disturbances. In this paper, transient stability for a small power plant (80MW) has been studied through ETAP...
A microgrid comprised of wind, PV, and fuel cell generation systems along with a micro-alternator and a storage system is considered in this study. The small signal behavior of the system is investigated considering the real part of the dominant eigenvalues. The impact of the participation of the distributed generation sources on the small-signal stability has been investigated. While it is essential...
This paper presents a procedural content generation algorithm for the physics-based puzzle game Angry Birds. The proposed algorithm creates complex stable structures using a variety of 2D objects. These are generated without the aid of pre-defined substructures or composite elements. The structures created are evaluated based on a fitness function which considers several important structural aspects...
Distributed renewable energy sources progressively gain importance in power systems, with which new challenges, but also new opportunities, arise. Therefore, it is necessary to analyze the interaction between this type of generators and the grid, and to study adequate control methods that allow small generating units to operate harmoniously within power systems and contribute to their control, stability,...
Wide-area measurement-based voltage stability assessment (VSA) by coupled single-port circuit models has been widely discussed recently. This method models the coupling effects of load buses within a meshed network into extra impedance of a single-port model for each load bus. In simulation studies, overestimations of voltage stability margin using this approach have been observed when critical load...
The tools used for assessment of rotor angle stability should be able to estimate the domain of attraction and the ensuing control laws which would aid in enhancing it. The widely used energy function formulations have limitations in being extended for lossy N-machines owing to the presence of transfer conductances obtained due to the modeling approaches used in transient stability studies. This problem...
Voltage and local reliability (VLR) are critical to reliable operation of the grid. Centralized electricity markets optimize active power in the market clearing software. VLR commitment requirements are mostly identified through out of market operational procedures. This paper introduces the approaches that Midcontinent Independent System Operator (MISO) has taken to incorporate VLR requirement into...
Transient stability is a major concern for doubly fed induction machine (DFIM). A DFIM based wind generator is readily affected by faults at the grid side, as it's stator windings are interfaced to grid. However, the wind generators need to remain connected and continue operation during faults at the grid side according to the grid code requirements. Therefore it is important to enhance the transient...
High penetrations of distributed renewables can dramatically increase uncertainty in the transmission system, making small-signal stability verification far more challenging. In this paper, we examine the impact of generating 30% of the power in the IEEE 118 bus test network with 118 distributed renewable sources, and show the inadequacy of sampling approaches to stability analysis. We show that multipoint...
Modal analysis is the well-established method for investigating small-signal stability. Dominant states of a particular oscillatory or monotonous mode can be identified by linearizing the system's differential equations. Since generator oscillation is predominantly influenced by the speed deviation and the rotor angle, whereas other state variables play a minor role, an approach to reduce a generator's...
In the context of voltage stability, this paper describes a fast algorithm that estimates the maximum loadability point (MLP) of a power system from its power flow equations. First it estimates the load level where each generator reaches its reactive limit, this is done using a quadratic curve fitting technique. After that another quadratic curve is used to estimate the MLP. From two power flow solutions,...
The control system is a key technology to extract maximum energy from the incident wind. By regulating aerodynamic control, it is possible to adapt the changes in wind speed by controlling shaft speed. Thus, the turbine generator can track maximum power extracted from wind. In this paper, we propose a Lyapunov based switching control under quasi-linear ARX neural network (QARXNN) model to track maximum...
The availability of high-resolution, synchronized measurements from phasor measurement units (PMUs) presents an opportunity to develop advanced analytical techniques for evaluation of power system dynamic performance?? This paper proposes a PMU-based technique for online monitoring of power system stability. The algorithm of Maximum Lyapunov Exponent (MLE) is used to determine if a power system swing...
Dynamic stability issues of power converter interfaced devices integrating into the power grid have drawn increased attention. This paper studies DC-link voltage control stability for a weak-ac-grid connected wind farm, in which doubly-fed induction generator (DFIG) based wind turbines (WTs) operate in parallel. First, a reduced analytical model is proposed of separated dynamics for different time...
There has recently been interest in diversifying the technologies that provide primary frequency control of the power grid beyond generation. One method of interest to obtain frequency control by turning on or off flexible loads in response to local measurements of line frequency. Because of the large number of loads involved, it is desirable to implement this control without communication among the...
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