SMOOTH AND NONSMOOTH BIFURCATIONS IN MULTI-STRUCTURE MULTI-OPERATING-MODE HYBRID POWER SYSTEMS

2013 ◽  
Vol 23 (05) ◽  
pp. 1350094 ◽  
Author(s):  
XIAOLING XIONG ◽  
CHI K. TSE ◽  
XINBO RUAN
Keyword(s):  
Power Systems ◽  
Hybrid Systems ◽  
General Procedure ◽  
Dynamical Behavior ◽  
Formal System ◽  
Operating Conditions ◽  
Stable Operation ◽  
Operating Modes ◽  
Hybrid Power ◽  
Averaged Model

Hybrid renewable power generation systems have been developed rapidly in recent years. Due to the inherent fluctuation of availability of energy from renewable sources, systems that are designed to capture energy from such sources and deliver it in loads have to cope with the difficult challenges of maintaining stability under all possible operating conditions. As a result, the structures and operating modes of such hybrid systems are inherently time-varying. Due to their multiple structures and operating-modes, hybrid systems have rather complex dynamic behavior and the design for stable operation requires thorough consideration of the effects of variation in parameters on the operating modes and corresponding stability statuses. This paper presents a formal system description for such systems and a general procedure for analyzing the change of dynamical behavior under parameter variations (i.e. bifurcation) of this kind of systems. A hybrid power system consisting of dual-input buck converters is taken as an example for illustrating the possible complex behavior. We reveal smooth and nonsmooth bifurcation phenomena in this system. Under certain conditions, nonsmooth bifurcations have been observed and verified with full-circuit simulations. Moreover, a detailed analysis based on an averaged model is performed to identify two specific types of bifurcation and evaluate the stability boundaries of the system.

Models and Methods for Studying Factors Influencing the Performance of a Hybrid Guaranteed Power Supply Complex

Vestnik MEI ◽  
2021 ◽  
pp. 58-68
Author(s):  
Mikhail G. Tyagunov ◽  
◽  
Razhidin P. Sheverdiev ◽  
Keyword(s):  
Power Systems ◽  
Power Supply ◽  
Renewable Energy Sources ◽  
Operating Conditions ◽  
Parallel Operation ◽  
Hybrid Energy ◽  
Operating Modes ◽  
Energy Complex ◽  
Factors Influencing ◽  
Power Installations

The aim of the work is to study the factors influencing the composition, parameters, and operation modes of a hybrid energy complex intended for providing guaranteed power supply to consumers located in isolated and hard-to-reach areas. The article presents mathematical models of the operating modes of power installations based on renewable energy sources as part of a hybrid energy complex involving parallel operation of different types of energy storage units, with taking into account the lifecycle, technical and process features of their functioning in isolated power systems. A 3D model of the hybrid energy complex has been developed, using which its performance can be studied under operating conditions close to real ones. In addition, a methodology of applying the model in solving design problems concerned with substantiating the parameters of isolated systems supplying power to consumers in hard-to-reach areas has been elaborated.

scholarly journals SIMULATION MODEL AND RESEARCH OF QUASI-STEADY-STATE AND DYNAMIC OPERATION MODES OF THE AUTONOMOUS DC POWER ENERGY SYSTEM WITH PARALLEL OPERATED INVERTER EXCITED INDUCTION GENERATORS

2021 ◽  
Vol 1 (53) ◽  
pp. 43-50
Author(s):  
L. Mazurenko ◽  
◽  
O. Dzura ◽  
Ye. Shumskyi ◽  
◽  
...  
Keyword(s):  
Power Systems ◽  
Simulation Models ◽  
Electrical Energy ◽  
Energy System ◽  
Energy Performance ◽  
Stable Operation ◽  
Operating Modes ◽  
Induction Generators ◽  
Dc Power ◽  
Dc Power Systems

Purpose. The development of theory and research of autonomous DC power systems based on contactless electrical machines is an important element in ensuring the improvement of the reliability and energy efficiency of autonomous power supply of remote from centralized networks facilities, ship equipment, critical to power outages consumers. Originality. The use of induction generators with squirrel-cage rotor and an electronic converter in stator circuits in the design of autonomous DC power systems is advisable due to presence of a DC power output in these generators and the possibility of stabilizing the output voltage at variable speed. One of the scientific issues needed to be solved at creating induction generators-based DC power systems with inverter-assisted self-excitation of the generators is the determination of means and as well as development and verification of algorithms for regulating the generators load. Solving this issue requires the creation of appropriate simulation models. Methodology. In this work, a simulation dynamic model of an autonomous DC power system with two parallel operated induction generators with inverterassisted self-excitation and the six-step switching control algorithm has been developed. Results. A study of quasisteady-state and dynamic operating modes of the system was carried out. The duration of the initial excitation of the generators was determined for different values of the capacitance of the filter. Practical value. The results obtained showed the compliance of the parameters of electrical energy in the system with the standards established by the relevant regulatory documents and stable operation of the system with load changing from idle to rated. Further work is planned to focus on improving control algorithms for autonomous DC power systems with parallel operating induction generators and inverter-assisted self-excitation, studying the energy performance of such systems and developing recommendations for their design.

scholarly journals Hybrid Power System for the Range Extension of Security Robots: Specification Development Phase

2021 ◽  
Vol 11 (23) ◽  
pp. 11577
Author(s):  
Woosuk Sung
Keyword(s):  
Power Systems ◽  
Power System ◽  
Operating Conditions ◽  
Critical Conditions ◽  
Development Phase ◽  
Hybrid Power System ◽  
Hybrid Power ◽  
Long Duration ◽  
Main Development ◽  
Development Goals

This paper describes our best practices related to hybrid power system (HPS) development, with a focus on the specification development phase. The HPS specifications are based on the main development goals of our security robot, which place top priority on 24 h continuous operation on a single charge. Similar to human guards, security robots are expected to operate 24 h per day, seven days per week, but existing battery-powered robots cannot meet these goals. For long-duration missions, their operating times are too short, and their charging times are too long. As an effective alternative, hydrogen fuel cells are combined with batteries to hybridize the power systems of security robots. In this study, several HPS structures were comprehensively compared by selecting a one-stage series structure. Component specifications were determined based on the selected structure to achieve the main development goals of our security robot. To verify whether the determined specifications are valid, a HPS simulator was developed. The key operating conditions for the HPS were simulated, including overloading, terminal short-circuiting, and drive cycling. Under critical conditions, the behavior of the entire system and its components was confirmed. The developed specifications will eventually be carried over to the prototyping phase.

Stability and Evolutionary Trend of Hopf Bifurcations in Double-Input SEPIC DC–DC Converters

2019 ◽  
Vol 29 (14) ◽  
pp. 1950192 ◽  
Author(s):  
Hao Zhang ◽  
Min Jing ◽  
Shuai Dong ◽  
Dachu Dong ◽  
Ye Liu ◽  
...  
Keyword(s):  
Power Systems ◽  
Circuit Design ◽  
Hopf Bifurcations ◽  
Evolutionary Trend ◽  
Hybrid Power Systems ◽  
Coupling Effects ◽  
Stability Boundaries ◽  
Hybrid Power ◽  
The Stability ◽  
Averaged Model

In this paper, the stability and evolutionary trend of Hopf bifurcations are investigated thoroughly for the double-input SEPIC DC–DC converter with one-cycle control (OCC), which is widely used in hybrid power systems. By means of cycle-by-cycle simulations, the evolutionary trend of bifurcation behaviors is identified. The inherent mechanisms of two types of bidirectional Hopf bifurcations are uncovered based on the proposed averaged model. Moreover, stability boundaries in the parameter space are derived with the help of eigenvalue analysis to optimize the circuit design. Furthermore, some important indices with respect to coupling effects are evaluated to assess the coupling effects in the system. Finally, PSpice circuit experiments are performed to verify the bifurcation analysis.

Development of Hybrid Power Systems Based on Direct Fuel Cell/Turbine Cycle

2005 ◽  
Author(s):  
Hossein Ghezel-Ayagh ◽  
Robert Sanderson ◽  
Jim Walzak
Keyword(s):  
Fuel Cell ◽  
Power Systems ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Gas Turbines ◽  
Power Plants ◽  
High Efficiency ◽  
Mechanical Design ◽  
Thermodynamic Cycle ◽  
Hybrid Power

FuelCell Energy Inc. (FCE) is developing ultra high efficiency Direct FuelCell/Turbine® (DFC/T®) hybrid power plants. Present activities are focused both on the demonstration of the DFC/T concept in small packaged hybrid power generation units for distributed generation, and the design of multi-megawatt (Multi-MW) hybrid systems for the wholesale electric power market. The development of Multi-MW DFC/T systems has been focused on the on the design of power plants with efficiencies approaching 75% (LHV of natural gas). The design efforts included thermodynamic cycle analysis of key gas turbine parameters such as compression ratio. The power plant designs were studied for near-term deployment utilizing the existing commercially available gas turbines and long-term deployment requiring advanced gas turbine technologies. A new fuel cell cluster concept was developed for mechanical design of Multi-MW systems. The concept utilizes the existing one-MW fuel cell modules as the building block for the Multi-MW hybrid systems.

Distributed Modeling Of Building Systems Through Cyber-Physical Integration

2019 ◽  
pp. 12-17
Keyword(s):  
Data Structure ◽  
Operating Conditions ◽  
Physical Models ◽  
Distributed Model ◽  
Physical Processes ◽  
Distributed Modeling ◽  
Distributed Models ◽  
Operating Modes ◽  
Building Systems ◽  
Important Practical Application

This article describes the proposed approaches to creating distributed models that can, with given accuracy under given restrictions, replace classical physical models for construction objects. The ability to implement the proposed approaches is a consequence of the cyber-physical integration of building systems. The principles of forming the data structure of designed objects and distributed models, which make it possible to uniquely identify the elements and increase the level of detail of such a model, are presented. The data structure diagram of distributed modeling includes, among other things, the level of formation and transmission of signals about physical processes inside cyber-physical building systems. An enlarged algorithm for creating the structure of the distributed model which describes the process of developing a data structure, formalizing requirements for the parameters of a design object and its operating modes (including normal operating conditions and extreme conditions, including natural disasters) and selecting objects for a complete group that provides distributed modeling is presented. The article formulates the main approaches to the implementation of an important practical application of the cyber-physical integration of building systems - the possibility of forming distributed physical models of designed construction objects and the directions of further research are outlined.

THE ANALYSIS OF OPERATION MODES OF ENERGY STORES IN AUTONOMOUS HYBRID POWER PLANTS WITH RENEWABLE ENERGY RESOURCES

2018 ◽  
pp. 55-67
Author(s):  
S. G. Obukhov ◽  
I. A. Plotnikov ◽  
V. G. Masolov
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Low Frequency ◽  
Rechargeable Batteries ◽  
Energy Resources ◽  
Renewable Energy Resources ◽  
Hybrid Power ◽  
Operation Modes ◽  
Energy Stores ◽  
Energy Store

The paper presents the results of the comparative analysis of operation modes of an autonomous hybrid power complex with/without the energy store. We offere the technique which defines the power characteristics of the main components of a hybrid power complex: the consumers of the electric power, wind power and photo-electric installations (the last ones have been constructed). The paper establishes that, in order to compensate the seasonal fluctuations of power in autonomous power systems with renewable energy resources, the accumulative devices are required, with a capacity of tens of MWh including devices that are capable to provide energy storage with duration about half a year. This allows abandoning the storage devices for smoothing the seasonal fluctuations in the energy balance.The analysis of operation modes of energy stores has shown that for a stock and delivery of energy on time intervals, lasting several hours, the accumulative devices with rather high values of charging and digit power aren't required. It allows using the lead-acid rechargeable batteries of the deep category for smoothing the daily peaks of surplus and a capacity shortage. Moreover, the analysis of operation modes of energy stores as a part of the hybrid complexes has demonstrated that in charging/digit currents of the energy store the low-frequency and high-frequency pulsations of big amplitude caused by changes of size of output power of the renewable power installations and loading are inevitable. If low-frequency pulsations (the period of tens of minutes) can partially be damped due to the restriction of size of the maximum charging current of rechargeable batteries, then it is essentially impossible to eliminate high-frequency pulsations (the period of tens of seconds) in the power systems with the only store of energy. The paper finds out that the combined energy store having characteristics of the accumulator in the modes of receiving and delivery of power on daily time intervals, and at the same time having properties of the supercondenser in the modes of reception and return of impulses of power on second intervals of time is best suited to requirements of the autonomous power complexes with renewable energy resources.

CHAOTIC OPERATING MODES OF POWER SYSTEMS WITH DISTRIBUTED GENERATION

2020 ◽  
Vol 2 (1) ◽  
pp. 027-031
Author(s):  
B. A. Kosarev ◽  
◽  
O. A. Lysenko ◽  
V. K. Fedorov ◽  
R. N. Khamitov ◽  
...  
Keyword(s):  
Power Systems ◽  
Distributed Generation ◽  
Operating Modes

Reliability Index of Wind-Solar Hybrid Power Plants using the Expected Energy Not Supplied Method

2019 ◽  
Vol 8 (4) ◽  
pp. 9449-9456
Keyword(s):  
Power Plant ◽  
Power Systems ◽  
Electricity Market ◽  
Reliability Index ◽  
Power Plants ◽  
Initial Conditions ◽  
Hybrid Plant ◽  
Total Power ◽  
Hybrid Power ◽  
Hybrid Power Plant

This paper proposes the reliability index of wind-solar hybrid power plants using the expected energy not supplied method. The location of this research is wind-solar hybrid power plants Pantai Baru, Bantul, Special Region of Yogyakarta, Indonesia. The method to determine the reliability of the power plant is the expected energy not supplied (EENS) method. This analysis used hybrid plant operational data in 2018. The results of the analysis have been done on the Pantai Baru hybrid power plant about reliability for electric power systems with EENS. The results of this study can be concluded that based on the load duration curve, loads have a load more than the operating kW of the system that is 99 kW. In contrast, the total power contained in the Pantai Baru hybrid power plant is 90 kW. This fact makes the system forced to release the load. The reliability index of the power system in the initial conditions, it produces an EENS value in 2018, resulting in a total value of 2,512% or 449 kW. The EENS value still does not meet the standards set by the National Electricity Market (NEM), which is <0.002% per year. Based on this data, it can be said that the reliability of the New Coast hybrid power generation system in 2018 is in the unreliable category.

Optimal Placement of FACTS Devices for Voltage Stability Improvement with Economic Consideration Using Firefly Algorithm

2019 ◽  
Vol 14 (1) ◽  
pp. 5-11
Author(s):  
S. Rajasekaran ◽  
S. Muralidharan
Keyword(s):  
Power Systems ◽  
Voltage Stability ◽  
Firefly Algorithm ◽  
Transmission System ◽  
Operating Conditions ◽  
Optimal Placement ◽  
Voltage Collapse ◽  
Facts Devices ◽  
The Cost ◽  
Bus System

Background: Increasing power demand forces the power systems to operate at their maximum operating conditions. This leads the power system into voltage instability and causes voltage collapse. To avoid this problem, FACTS devices have been used in power systems to increase system stability with much reduced economical ratings. To achieve this, the FACTS devices must be placed in exact location. This paper presents Firefly Algorithm (FA) based optimization method to locate these devices of exact rating and least cost in the transmission system. Methods: Thyristor Controlled Series Capacitor (TCSC) and Static Var Compensator (SVC) are the FACTS devices used in the proposed methodology to enhance the voltage stability of power systems. Considering two objectives of enhancing the voltage stability of the transmission system and minimizing the cost of the FACTS devices, the optimal ratings and cost were identified for the devices under consideration using Firefly algorithm as an optimization tool. Also, a model study had been done with four different cases such as normal case, line outage case, generator outage case and overloading case (140%) for IEEE 14,30,57 and 118 bus systems. Results: The optimal locations to install SVC and TCSC in IEEE 14, 30, 57 and 118 bus systems were evaluated with minimal L-indices and cost using the proposed Firefly algorithm. From the results, it could be inferred that the cost of installing TCSC in IEEE bus system is slightly higher than SVC.For showing the superiority of Firefly algorithm, the results were compared with the already published research finding where this problem was solved using Genetic algorithm and Particle Swarm Optimization. It was revealed that the proposed firefly algorithm gives better optimum solution in minimizing the L-index values for IEEE 30 Bus system. Conclusion: The optimal placement, rating and cost of installation of TCSC and SVC in standard IEEE bus systems which enhanced the voltage stability were evaluated in this work. The need of the FACTS devices was also tested during the abnormal cases such as line outage case, generator outage case and overloading case (140%) with the proposed Firefly algorithm. Outputs reveal that the recognized placement of SVC and TCSC reduces the probability of voltage collapse and cost of the devices in the transmission lines. The capability of Firefly algorithm was also ensured by comparing its results with the results of other algorithms.

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