Slow flow solutions and stability analysis of single machine to infinite bus power systems

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
M. G. Suresh Kumar ◽  
C. A. Babu
Keyword(s):  
Power Systems ◽  
Power System ◽  
Single Machine ◽  
Multiple Scales ◽  
Operating Conditions ◽  
Phase Portraits ◽  
Slow Flow ◽  
Approximate Analytical Expression ◽  
Flow Equations ◽  
Load Angle

Abstract Nonlinearity is a major constraint in analysing and controlling power systems. The behaviour of the nonlinear systems will vary drastically with changing operating conditions. Hence a detailed study of the response of the power system with nonlinearities is necessary especially at frequencies closer to natural resonant frequencies of machines where the system may jump into the chaos. This paper attempt such a study of a single machine to infinite bus power system by modelling it as a Duffing equation with softening spring. Using the method of multiple scales, an approximate analytical expression which describes the variation of load angle is derived. The phase portraits generated from the slow flow equations, closer to the jump, display two stable equilibria (centers) and an unstable fixed point (saddle). From the analysis, it is observed that even for a combination of parameters for which the system exhibits jump resonance, the system will remain stable if the variation of load angle is within a bounded region.

Harmonically Excited Delay Equation for Machine Tool Vibrations

2018 ◽  
Author(s):  
János Lelkes ◽  
Tamás Kalmár-Nagy
Keyword(s):  
Multiple Scales ◽  
Phase Portraits ◽  
Slow Flow ◽  
Flow Equations ◽  
Vibration Model ◽  
External Sources ◽  
Tool Vibrations ◽  
Local And Global Bifurcations ◽  
Direct Numerical Integration ◽  
Delay Differential

A machining tool can be subject to different kinds of excitations. The forcing may have external sources (such as rotating imbalance or misalignment of the workpiece) or it can arise from the cutting process itself (e.g. chip formation). We investigate the classical tool vibration model which is a delay-differential equation with a quadratic and cubic nonlinearity and periodic forcing. The method of multiple scales was used to derive the slow-flow equations. The resonance curves of the system are similar to those for the Duffing-equation, having a hardening characteristic. Stability analysis for the fixed points of the slow-flow equations was performed. Local and global bifurcations were studied and illustrated with phase portraits and direct numerical integration of the original equation. Subcritical Hopf, saddle-node and heteroclinic bifurcations were found.

Chaotic dynamics for a class of single-machine-infinite bus power system

2016 ◽  
Vol 24 (3) ◽  
pp. 582-587 ◽  
Author(s):  
Liangqiang Zhou ◽  
Fangqi Chen
Keyword(s):  
Power Systems ◽  
Power System ◽  
Single Machine ◽  
Chaotic Dynamics ◽  
Numerical Results ◽  
Chaotic Motions ◽  
System Parameters ◽  
Critical Curves ◽  
Single Machine Infinite Bus

The chaotic motions are investigated both analytically and numerically for a class of single-machine-infinite bus power systems. The mechanism and parametric conditions for chaotic motions of this system are obtained rigorously. The critical curves separating the chaotic and non-chaotic regions are presented. The chaotic feature of the system parameters is discussed in detail. It is shown that there exist chaotic bands for this system, and the bands vary with the system parameters. Some new dynamical phenomena are presented. Numerical results are given, which verify the analytical ones.

scholarly journals An approach for a multi-stage under-frequency based load shedding scheme for a power system network

2020 ◽  
Vol 10 (6) ◽  
pp. 6071
Author(s):  
Mkhululi Elvis Siyanda Mnguni ◽  
Yohan Darcy Mfoumboulou
Keyword(s):  
Decision Making ◽  
Power Systems ◽  
Power System ◽  
New England ◽  
Operating Conditions ◽  
Load Shedding ◽  
Power Network ◽  
Load Demand ◽  
Multi Stage ◽  
System Frequency

The integration of load shedding schemes with mainstream protection in power system networks is vital. The traditional power system network incorporates different protection schemes to protect its components. Once the power network reaches its maximum limits, and the load demand continue to increase the whole system will experience power system instability. The system frequency usually drops due to the loss of substantial generation creating imbalance. The best method to recover the system from instability is by introducing an under-frequency load shedding (UFLS) scheme in parallel with the protection schemes. This paper proposed a new UFLS scheme used in power systems and industry to maintain stability. Three case studies were implemented in this paper. Multi-stage decision-making algorithms load shedding in the environment of the DIgSILENT power factory platform is developed. The proposed algorithm speeds-up the operation of the UFLS scheme. The load shedding algorithm of the proposed scheme is implemented as a systematic process to achieve stability of the power network which is exposed to different operating conditions. The flexibility of the proposed scheme is validated with the modified IEEE 39-bus New England model. The application of the proposed novel UFLS schemes will contribute further to the development of new types of engineers.

scholarly journals Steady state stability in electrical power systems considering operation limits in generators, transformers and transmission lines

2021 ◽  
Vol 18 (2) ◽  
Author(s):  
Fredy Estuardo Tamayo Guzmán ◽  
Carlos Andrés Barrera-Singaña
Keyword(s):  
Steady State ◽  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Electrical Power ◽  
Operating Conditions ◽  
Electrical Power Systems ◽  
Capacity Curves ◽  
Remedial Actions ◽  
Steady State Stability

Electrical power systems are exposed to several events that can cause unstable operation scenarios. This is due to improper operation of certain components. If an event occurs, the system must be designed to overcome that contingency, thus remaining in a permanent condition that must be evaluated in order to monitor and prevent a possible collapse of the system. An evaluation of steady state stability is proposed at this work based on the capacity curves of generators, transformers and transmission lines. These remarked curves provide information on the operation point of these elements, thus allowing the application of remedial actions. PowerFactory and Matlab are used to carry out the tool for monitoring the operation points after a contingency. The effectiveness of the developed tool is validated at the IEEE 39-bus power system model, where results shows that the functionalaty for different contingencies based on the operating conditions when the components of the power system are varied, cosnquently, the tool identifies cases that require actions at the operational level.

Application of Moth Flame Optimization Algorithm for AGC of Multi-Area Interconnected Power Systems

2018 ◽  
Vol 7 (1) ◽  
pp. 22-49 ◽  
Author(s):  
Ajit Kumar Barisal ◽  
Deepak Kumar Lal
Keyword(s):  
Power Systems ◽  
Power System ◽  
Pid Controller ◽  
Thermal Power ◽  
Operating Conditions ◽  
System Model ◽  
Source Power ◽  
Interconnected Power Systems ◽  
Thermal Power System ◽  
Moth Flame Optimization Algorithm

A novel attempt has been made to use Moth Flame Optimization (MFO) algorithm to optimize PI/PID controller parameters for AGC of power system. Four different power systems are considered in the present article. Initially, a two area thermal power system is considered for simulation. The superiority of the proposed MFO optimized PI/PID controller has been demonstrated by comparing the results with recently published approaches such as conventional, GA, BFOA, DE, PSO, Hybrid BFOA-PSO, FA and GWO algorithm optimized PI/PID controller for the same power system model. Then, a sensitivity analysis is carried out to study the robustness of the system to wide changes in the operating conditions and system parameters from their nominal values. The proposed approach is extended to different realistic multi-area multi-source power systems with diverse sources of power generations for simulation study. The acceptability and efficacy of the proposed technique is demonstrated by comparing with other recently published techniques.

scholarly journals Nonlinear robust control for single-machine infinite-bus power systems with input saturation

2017 ◽  
Vol 65 (1) ◽  
pp. 3-9
Author(s):  
Y. Wan
Keyword(s):  
Power Systems ◽  
Power System ◽  
Single Machine ◽  
Input Saturation ◽  
Control Law ◽  
System A ◽  
Control Scheme ◽  
Single Machine Infinite Bus ◽  
The Stability ◽  
Nonlinear Robust

Abstract In this paper, a new control scheme is proposed to achieve stability for a single-machine infinite-bus power system. A power system model simultaneously considering input saturation and time-varying uncertainties is presented. A sufficient condition for the system convergence is given and based on this result, a switching excitation control law with auxiliary system is designed. The stability analysis and simulation results all show that the developed controller is effective.

scholarly journals ON THE SIMULATION OF MODES ОF ELECTRIC POWER SYSTEMS WITH FACTS

2017 ◽  
Vol 60 (4) ◽  
pp. 341-351
Author(s):  
E. D. Halilov
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Power Flow ◽  
Power Transmission ◽  
Electric Power Systems ◽  
Active Power ◽  
Operating Conditions ◽  
Electrical Networks ◽  
Facts Devices

Power flow control is an important task of development of electric power systems. It is necessary to reduce the power loss, improve the reliability and quality of power supply and increase the power transmission. Currently, on the basis of modern power electronics effective FАСТS devices for flexible control of power system operation modes have been developed. FАСТS devices are able to simultaneously influence the voltage, the reactance, the angle between the voltages. As it is known, the calculations of the established modes of electric systems are the most frequently performed tasks at all the territorial and time levels of control and planning operations. These calculations are significant by themselves, being also an integral part of software systems of calculation of losses of power and energy in electrical networks, calculation of optimal modes and also sustainability. The need for multiple mode calculation imposes high requirements to the methods of calculation of the established modes in real time in terms of performance and reliability of the results of the solution being obtained under operating conditions of electric power systems. In traditional calculations of the established modes of electrical networks, shunt reactors, current-limiting reactors, capacitor banks, longitudinal compensation devices were accounted in the simulation as passive elements. In regard with the introduction of FACTS devices in power systems, there is an arising need to develop appropriate algorithms and implement them in the form of software for analyzing and controlling the established modes of power systems. The methodology and software for calculation of the established modes of electric networks with consideration of FACTS devices have been developed. The software makes it possible to obtain practically acceptable solutions in three outer iterations. Based on the results of numerical simulation of modes of the power system of the “Azerenergy” JSC it was determined that the application of FACTS devices can significantly increase the transmission line active power, improve voltage levels and reduce losses of active power. The dependences of flows and power losses on the control parameter of FACTS devices have been derived. 

Robust decentralized model predictive load-frequency control design for time-delay renewable power systems

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gaber Magdy ◽  
Abualkasim Bakeer ◽  
Mohammed Alhasheem
Keyword(s):  
Time Delay ◽  
Power Systems ◽  
Power System ◽  
Frequency Stability ◽  
Operating Conditions ◽  
Load Frequency Control ◽  
Communication Delays ◽  
Renewable Power ◽  
Control Scheme ◽  
Decentralized Model

Abstract A robust decentralized model predictive control (DMPC) design is proposed for frequency stability of hybrid renewable power systems considering high renewables energy penetration and nonlinearity effects. The Egyptian power system (EPS) considered as a test system comprises both traditional power stations (i.e., steam, gas, combined cycle, and hydraulic power plants) and renewable energy sources (RESs). Where the considered RESs contain both the wind power generated from Zafarana and Gabel El-Zeit wind farms and the solar power generated from Benban solar park, which is considered one of the world’s largest photovoltaic (PV) plants. To obtain an accurate insight into a real modern power system, this research takes into account the effects of the important nonlinearity such as generation rate constraints (GRCs), governor deadband (GDB), and communication time delay (CTD). The designed control is set based on the DMPC for each subsystem independently to ensure the frequency stability of the whole system as each subsystem has different characteristics and operating constraints than the others. Moreover, the decentralized control scheme has become imperative for large power systems due to the high cost of transmitting data over long distances and the probability of error occurrence with the centralized control scheme. To verify the effectiveness and robustness of the proposed DMPC for the EPS, it is compared with the centralized MPC (CMPC) scheme in different operating conditions. The simulation results, which are conducted using MATLAB/SIMULINK® software, emphasized that the proposed DMPC scheme can effectively handle several load disturbances, high uncertainty in the system parameters, and random communication delays. Hence, it can regulate the grid frequency and ensure the robust performance of the studied renewable power system with high RESs penetration and maximum communication delays in the system.

Power Flow Modeling in Power System With Multiple FACTS Controller

2018 ◽  
pp. 194-209
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Flow ◽  
Phase Shifter ◽  
Unified Power Flow Controller ◽  
Static Synchronous Compensator ◽  
Transmission Systems ◽  
Flow Equations ◽  
Flexible Ac Transmission ◽  
Facts Devices

Flexible AC transmission systems (FACTS) devices are integrated into power system networks to control power flow, increase transmission line capability to its thermal limit, and improve the security of transmission systems. Power flow is an important mathematical calculation for planning, operation, and control of power systems network. The focus of the chapter is to explore how to modify Newton-Raphson power flow method to include various FACTS devices such as static VAR compensator (SVC), static synchronous compensator (STATCOM), static synchronous series compensator (SSSC), thyristor-controlled series capacitor (TCSC), thyristor-controlled phase shifter (TCPS), unified power flow controller (UPFC) controllers. This chapter briefly describes the power flow equations of the aforesaid FACTS-based power system network, and how the conventional power flow calculation is systematically extended to include these controllers is also been discussed.

Sign in / Sign up

Export Citation Format

Share Document