scholarly journals Deriving Specifications for Coupling through Dual-Wound Generators

2018 ◽  
Author(s):  
L J Rashkin ◽  
J C Neely ◽  
D G Wilson ◽  
S F Glover ◽  
N Doerry ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Control Strategies ◽  
Electromagnetic Coupling ◽  
The Other ◽  
Successful Implementation ◽  
Generator System ◽  
System Architectures ◽  
Dc Voltage ◽  
Coupling Mechanisms

Many candidate power system architectures are being evaluated for the Navy’s next generation all-electric warship. One proposed power system concept involves the use of dual-wound generators to power both the Port and Starboard side buses using different 3-phase sets from the same machine (Doerry, 2015). This offers the benefit of improved efficiency through reduced engine light-loading and improved dispatch flexibility, but the approach couples the two busses through a common generator, making one bus vulnerable to faults and other dynamic events on the other bus. Thus, understanding the dynamics of cross-bus coupling is imperative to the successful implementation of a dual-wound generator system. In (Rashkin, 2017), a kilowatt-scale system was analysed that considered the use of a dual-wound permanent magnet machine, two passive rectifiers, and two DC buses with resistive loads. For this system, dc voltage variation on one bus was evaluated in the time domain as a function of load changes on the other bus. Therein, substantive cross-bus coupling was demonstrated in simulation and hardware experiments. The voltage disturbances were attributed to electromechanical (i.e. speed disturbances) as well as electromagnetic coupling mechanisms. In this work, a 25 MVA dual-wound generator was considered, and active rectifier models were implemented in Matlab both using average value modelling and switching (space vector modulation) simulation models. The frequency dynamics of the system between the load on one side and the dc voltage on the other side was studied. The coupling is depicted in the frequency domain as a transfer function with amplitude and phase and is shown to have distinct characteristics (i.e. frequency regimes) associated with physical coupling mechanisms such as electromechanical and electromagnetic coupling as well as response characteristics associated with control action by the active rectifiers. In addition, based on requirements outlined in draft Military Standard 1399-MVDC, an approach to derive specifications will be discussed and presented. This method will aid in quantifying the allowable coupling of energy from one bus to another in various frequency regimes as a function of other power system parameters. Finally, design and control strategies will be discussed to mitigate cross-bus coupling. The findings of this work will inform the design, control, and operation of future naval warship power systems.

scholarly journals A Review of Virtual Inertia Techniques for Renewable Energy-Based Generators

2020 ◽  
Author(s):  
Ana Fernández-Guillamón ◽  
Emilio Gómez-Lázaro ◽  
Eduard Muljadi ◽  
Ángel Molina-Garcia
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Power Plants ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Extensive Discussion ◽  
Renewable Sources ◽  
Virtual Inertia ◽  
Alternative Sources

Over recent decades, the penetration of renewable energy sources (RES), especially photovoltaic and wind power plants, has been promoted in most countries. However, as these both alternative sources have power electronics at the grid interface (inverters), they are electrically decoupled from the grid. Subsequently, stability and reliability of power systems are compromised. Inertia in power systems has been traditionally determined by considering all the rotating masses directly connected to the grid. Thus, as the penetration of renewable units increases, the inertia of the power system decreases due to the reduction of directly connected rotating machines. As a consequence, power systems require a new set of strategies to include these renewable sources. In fact, ‘hidden inertia,’ ‘synthetic inertia’ and ‘virtual inertia’ are terms currently used to represent an artificial inertia created by inverter control strategies of such renewable sources. This chapter reviews the inertia concept and proposes a method to estimate the rotational inertia in different parts of the world. In addition, an extensive discussion on wind and photovoltaic power plants and their contribution to inertia and power system stability is presented.

An Underfrequency Load Shedding Scheme with Minimal Knowledge of System Parameters

2015 ◽  
Vol 16 (1) ◽  
pp. 33-46 ◽  
Author(s):  
Athbel Joe ◽  
S. Krishna
Keyword(s):  
Power Systems ◽  
Power System ◽  
New England ◽  
Load Shedding ◽  
Spinning Reserve ◽  
Generator System ◽  
Pass Filter ◽  
Low Pass Filter ◽  
System Parameters ◽  
Frequency Measurements

Abstract Underfrequency load shedding (UFLS) is a common practice to protect a power system during large generation deficit. The adaptive UFLS schemes proposed in the literature have the drawbacks such as requirement of transmission of local frequency measurements to a central location and knowledge of system parameters, such as inertia constant H and load damping constant D. In this paper, a UFLS scheme that uses only the local frequency measurements is proposed. The proposed method does not require prior knowledge of H and D. The scheme is developed for power systems with and without spinning reserve. The proposed scheme requires frequency measurements free from the oscillations at the swing mode frequencies. Use of an elliptic low pass filter to remove these oscillations is proposed. The scheme is tested on a 2 generator system and the 10 generator New England system. Performance of the scheme with power system stabilizer is also studied.

The Application of Safety and Stability Control Device in Middle of Henan Power Grid

2013 ◽  
Vol 860-863 ◽  
pp. 2068-2072
Author(s):  
Li Hua Zhang ◽  
Hui Lin Wang ◽  
Hong Qing Gan
Keyword(s):  
Control System ◽  
Power System ◽  
Control Strategies ◽  
Stability Control ◽  
Control Device ◽  
The Other ◽  
Stable Operation ◽  
Secondary Line ◽  
Stability Control System ◽  
Safety And Stability

Safety and stability control device is the secondary line of defense of power system stable operation. Firstly, this paper proposed the requisite of the regional safety and stability control system installed in Wuzhou 500kV switching station and the other two stations which belonged to the middle Henan power system. And then, it presented the components and elaborated control strategies of the system. It listed the situations of the united testing, at last, it summarized notes of this safety and stability control system in daily operation.

Integrated Power Flow Analysis with Large-scale Solar Photovoltaic Power Systems Employing N-R Method

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Girisha H Navada ◽  
K. N. Shubhanga
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Flow ◽  
Large Scale ◽  
Control Strategies ◽  
Linear Equations ◽  
Flow Analysis ◽  
Load Flow ◽  
Flow Equations ◽  
Single Machine Infinite Bus

Abstract A method is proposed to modify the conventional load flow programme to accommodate large-scale Solar PhotoVoltaics (SPV) power plant with series power specifications. The programme facilitates easy handling of any number of SPV systems with standard control strategies such as pf-control and voltage-control, considering solar inverter’s power constraints. In this method, the non-linear equations related to SPV systems, located at multiple locations, are solved with the main load flow equations in an integrated fashion, considerably reducing the implementation task. This task is achieved by augmenting the inverter buses to the existing power system network in such a way that the changes required in the conventional programme are minimal. To show the effectiveness of the proposed method, it is compared with the alternate-iteration method popularly followed in the literature. The workability of the proposed method has been demonstrated by using a Single Machine Infinite Bus (SMIB) system and the IEEE14-bus power system with SPV systems. Various test cases pertaining to meteorological variables and control strategies are also presented.

scholarly journals Adaptive Unified Differential Evolution Algorithm for Optimal Operation of Power Systems with Static Security, Transient Stability and Statcom Device

2019 ◽  
Vol 8 (4) ◽  
pp. 3309-3324
Keyword(s):  
Power Systems ◽  
Power System ◽  
Differential Evolution ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Voltage Stability ◽  
Transient Stability ◽  
Generator System ◽  
Optimal Power ◽  
Voltage Transient

The complexity of a power system operating with transient stability/security constraints increases with increased interconnection of power transmission networks. Many of the power system’s secure operations are affected with the voltage/transient instability problems. Thereby, the modern power systems have considered solving optimal power flow (OPF) problems using voltage/transient stability constraints as a tedious and challenging task. Algebraic and differential equations of the voltage/stability constraints are included in non-linear optimal power flow optimization problems. In this work, the OPF problems with voltage/stability constraints are solved using a newly developed reliable and robust technique. Moreover, the impact of a FACTS device such as STATCOM device was investigated to test its impact in the enhancement of power system performance. An adaptive unified differential evolution (AuDE) technique is proposed to search in the non-convex and nonlinear problems to obtain the global optimal solutions. Compared to other existing methods and basic DE, the proposed AuDE algorithm has achieved better results under simulation conditions. The power system’s performance is considerably enhanced with STATCOM device. Efficiency of the proposed method in solving the transient and security constrained power systems for optimal operations were demonstrated using the numerical results obtained from IEEE 39-bus, 10-generator system and IEEE 30-bus, 6-generator system. Due to page limitation only 30-bus systems results are presented.

Information Technology in Power System Planning and Operation under Deregulated Markets

2010 ◽  
pp. 377-399
Author(s):  
Fawwaz Elkarmi
Keyword(s):  
Information Technology ◽  
Power Systems ◽  
Power System ◽  
The Other ◽  
Small Systems ◽  
Deregulated Markets ◽  
Technology Tools ◽  
Technological Developments ◽  
Special Information ◽  
Planning And Operation

Power systems have grown recently in size and complexity to unprecedented levels. This means that planning and operation of power systems can not be made possible without the aid of information technology tools and instruments. Even small systems need such aid because of the complexity factor. On the other hand, new trends have recently emerged to solve the problems arising from increased size of power systems. These trends are related to the market structure, legal, and business issues. Other trends also cover technological developments, and environmental issues. Moreover, power systems have special characteristics and features that are not duplicated in other infrastructures. All these issues confirm the need for special information technology tools and instruments which aid in planning and operation of power systems.

scholarly journals Isolated and Interconnected Multi-Area Hybrid Power Systems: A Review on Control Strategies

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8276
Author(s):  
Sudhanshu Ranjan ◽  
Smriti Jaiswal ◽  
Abdul Latif ◽  
Dulal Chandra Das ◽  
Nidul Sinha ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Rural Areas ◽  
Fossil Fuels ◽  
Control Strategies ◽  
Renewable Energy Resources ◽  
Hybrid Power Systems ◽  
Hybrid Power System ◽  
Hybrid Power

Concerned with the increasing greenhouse gases in the atmosphere due to fossil fuels, the entire world is focusing on electricity generation through renewable energy resources. The most advantageous aspect of the distributed renewable sources is to provide the electricity to remote, scattered and the deprived rural areas by developing the hybrid power system at the smaller scale where power transmission through grid extension is not viable due to some economical, technical or environmental constraints for building new transmission lines. An accurate and adequate control strategy becomes inevitable to uphold the smooth operation by restraining the frequency and voltage deviation within its limit ensuring the highest degree of reliability of hybrid power system to provide an adequate power quality. In this paper, a comprehensive review of different control strategies adopted in isolated and interconnected multi-area hybrid power systems is presented.

scholarly journals Localized Transient Stability (LTS) Method for Real-time Localized Control

2018 ◽  
Vol 7 (1) ◽  
pp. 73
Author(s):  
Abdul Malek Miah
Keyword(s):  
Power Systems ◽  
Power System ◽  
New England ◽  
Real Time ◽  
Transient Stability ◽  
Stable Equilibrium ◽  
Measured Data ◽  
Test Results ◽  
Generator System ◽  
Full Power

<p>Very recently, a new methodology was introduced solely for the purpose of real-time localized control of transient stability. The proposed new method is based on the localized transient stability of a power system. This is completely a new idea in transient stability. In this method, the post-fault power system is represented by a two-generator localized power system at the site of each individual generator. If each of these localized power systems reaches its respective stable equilibrium, then the full power system also reaches its stable equilibrium. Therefore, in terms of real-time localized control of transient stability, if each of the localized power systems is driven to its respective stable equilibrium by local control actions with local computations using the locally measured data, then the full power system is driven to its stable equilibrium. Thus the method can be easily implemented for real-time localized control of transient stability. In this paper, the details of the mathematical formulations are presented. Some interesting test results on the well-known New England 39-bus 10-generator system are also presented in this paper to demonstrate the potential of the proposed method for use in real-time localized control of transient stability.</p><p> </p>

scholarly journals Application of optimal control for power systems considering renewable energy technologies

2021 ◽  
Author(s):  
◽  
Dhanpal Chetty
Keyword(s):  
Optimal Control ◽  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Wind Energy ◽  
Control Strategy ◽  
Control Strategies ◽  
Renewable Energy Sources ◽  
Optimal Control Strategy ◽  
Interconnected Power System

Over the last decade, power generation from renewable energy sources such as wind, hydro and solar energies have substantially increased globally and in South Africa. Of all the renewable energy sources, wind energy appears to be the most promising, considering design and costs. However, due to the intermittent nature of wind, the increased integration of wind energy into existing power systems raises several control challenges related to load frequency control (LFC) and tie-line power system stability. The stability of modern power systems, incorporating wind energy generations, will be significantly enhanced with the development of LFC strategies based on modern control theory, which is the focus of this research. This thesis presents the design, modelling and analysis, of two LFC control strategies for interconnected power systems, having wind power integrations. The first design is an optimal control strategy, based on error minimization through full state vector feedback, for a two-area interconnected power system consisting of hydro-thermal generations. The second design is a model predictive control (MPC) strategy, based output vector feedback of system state parameters, for a two-area interconnected power system consisting of thermal generations in each area. Both designs include the active power support from doubly fed induction generator based wind turbines (DFIG) in conjunction with the combined effort of a thyristor control phase shifter (TCPS) and super conducting magnetic energy storage unit (SMES). Both control strategies were simulated in MATLAB Simulink and positive results were obtained. The results show that the optimal control strategy is enhanced with power integrations using DFIG based wind turbines combined with the TCPS-SMES units and the MPC strategy is very robust and provides better dynamic performances even with parameter variations and generation rate restrictions.

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