Development and Investigation of a Proposed Voltage Sag Index

2012 ◽  
Vol 1 (1) ◽  
pp. 72-91
Author(s):  
Alexis Polycarpou

A proposed voltage sag index based on power flow equations is developed and investigated in this paper. The index supervises the power quality of a system, through calculating the voltage sag profile caused by an increase in reactive demand due to induction motor starting. Mathematical equations representing the load angle of the system are also derived. The accuracy of the index is investigated for a range of load, transmission, and distribution line X/R ratio values as well as various motor loading levels. Results demonstrate the effectiveness and applicability of the proposed index.

2019 ◽  
Vol 8 (2S11) ◽  
pp. 3374-3379

This project work presents a proposed D-STATCOM system, Which is implemented in the distribution network. In the present scenario, the customer or consumer should be supplied with a quality power. The power quality issues like voltage sag, swell, lightning surges etc, can be reduced by using several advanced techniques. Among all these power quality issues voltage sag is considered and has been compensated in this project work by using D-STATCOM. The major advantage of D-STATCOM is that instead of installing the compensating device in the transmission and distribution line, the D-STATCOM unit is implemented at the consumers premises to maintain stable voltage for the connected electrical equipment’s and also to provide safe operation of the electrical equipment’s by extending their life time. The software ie., implemented by using MATLAB Simulink and the results are also verified experimentally by a hardware unit


2011 ◽  
Vol 403-408 ◽  
pp. 3594-3599
Author(s):  
R. Selvarasu ◽  
C.Christober Asir Rajan

This paper presents the modeling and simulation of 14-bus system using TCSC and UPFC. Thyristor Controlled Series Compensator (TCSC) and Unified Power Flow Controller (UPFC) are included in 14-bus system to improve the power quality of the power system. The voltage sag is created by adding an extra load at the receiving end. This sag is compensated by using FACTS devices like TCSC and UPFC. Improvement in the voltage and power are presented using simulation studies.


2021 ◽  
Vol 13 (10) ◽  
pp. 5752
Author(s):  
Reza Sabzehgar ◽  
Diba Zia Amirhosseini ◽  
Saeed D. Manshadi ◽  
Poria Fajri

This work aims to minimize the cost of installing renewable energy resources (photovoltaic systems) as well as energy storage systems (batteries), in addition to the cost of operation over a period of 20 years, which will include the cost of operating the power grid and the charging and discharging of the batteries. To this end, we propose a long-term planning optimization and expansion framework for a smart distribution network. A second order cone programming (SOCP) algorithm is utilized in this work to model the power flow equations. The minimization is computed in accordance to the years (y), seasons (s), days of the week (d), time of the day (t), and different scenarios based on the usage of energy and its production (c). An IEEE 33-bus balanced distribution test bench is utilized to evaluate the performance, effectiveness, and reliability of the proposed optimization and forecasting model. The numerical studies are conducted on two of the highest performing batteries in the current market, i.e., Lithium-ion (Li-ion) and redox flow batteries (RFBs). In addition, the pros and cons of distributed Li-ion batteries are compared with centralized RFBs. The results are presented to showcase the economic profits of utilizing these battery technologies.


2011 ◽  
Vol 121-126 ◽  
pp. 1744-1748
Author(s):  
Xiang Yang Jin ◽  
Tie Feng Zhang ◽  
Li Li Zhao ◽  
He Teng Wang ◽  
Xiang Yi Guan

To determine the efficiency, load-bearing capacity and fatigue life of beveloid gears with intersecting axes, we design a mechanical gear test bed with closed power flow. To test the quality of its structure and predict its overall performance, we establish a three-dimensional solid model for various components based on the design parameters and adopt the technology of virtual prototyping simulation to conduct kinematics simulation on it. Then observe and verify the interactive kinematic situation of each component. Moreover, the finite element method is also utilized to carry out structural mechanics and dynamics analysis on some key components. The results indicate that the test bed can achieve the desired functionality, and the static and dynamic performance of some key components can also satisfy us.


Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1866
Author(s):  
Zahid Javid ◽  
Ulas Karaagac ◽  
Ilhan Kocar ◽  
Ka Wing Chan

There is an increasing interest in low voltage direct current (LVDC) distribution grids due to advancements in power electronics enabling efficient and economical electrical networks in the DC paradigm. Power flow equations in LVDC grids are non-linear and non-convex due to the presence of constant power nodes. Depending on the implementation, power flow equations may lead to more than one solution and unrealistic solutions; therefore, the uniqueness of the solution should not be taken for granted. This paper proposes a new power flow solver based on a graph theory for LVDC grids having radial or meshed configurations. The solver provides a unique solution. Two test feeders composed of 33 nodes and 69 nodes are considered to validate the effectiveness of the proposed method. The proposed method is compared with a fixed-point methodology called direct load flow (DLF) having a mathematical formulation equivalent to a backward forward sweep (BFS) class of solvers in the case of radial distribution networks but that can handle meshed networks more easily thanks to the use of connectivity matrices. In addition, the convergence and uniqueness of the solution is demonstrated using a Banach fixed-point theorem. The performance of the proposed method is tested for different loading conditions. The results show that the proposed method is robust and has fast convergence characteristics even with high loading conditions. All simulations are carried out in MATLAB 2020b software.


Author(s):  
Izudin Dzafic ◽  
E. Halilovic ◽  
Rabih A. Jabr ◽  
Bikash C. Pal ◽  
Dino Ablakovic

Author(s):  
M. G. Suresh Kumar ◽  
C. A. Babu

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.


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