Thyristor-Based FACTS Controllers for Electrical Transmission Systems

The zero-sum matrix game is one of the most classic game models, and it is widely used in many scientific and engineering fields. In the real world, due to the complexity of the decision-making environment, sometimes the payoffs received by players may be inexact or uncertain, which requires that the model of matrix games has the ability to represent and deal with imprecise payoffs. To meet such a requirement, this paper develops a zero-sum matrix game model with Dempster–Shafer belief structure payoffs, which effectively represents the ambiguity involved in payoffs of a game. Then, a decomposition method is proposed to calculate the value of such a game, which is also expressed with belief structures. Moreover, for the possible computation-intensive issue in the proposed decomposition method, as an alternative solution, a Monte Carlo simulation approach is presented, as well. Finally, the proposed zero-sum matrix games with payoffs of Dempster–Shafer belief structures is illustratively applied to the sensor selection and intrusion detection of sensor networks, which shows its effectiveness and application process.

https://www.mdpi.com/1424-8220/17/4/922/pdf

Zero-Sum Matrix Game with Payoffs of Dempster-Shafer Belief Structures and Its Applications on Sensors

Cell phones have become a necessity for many people throughout the world. The ability to keep in touch with family, business associates, and access to email are only a few of the reasons for the increasing importance of cell phones. However, the mobile-phones in early times were bulky, restrictive to only some features and worked only in areas where there was a good connection. All these problems were resolved by integrating a processor within a cell-phone. The processor is the central hub of your smartphone. It receives and executes every command, performing billions of calculations per second. The effectiveness of the processor directly affects every application you run, whether it's the camera, the music player, or just a simple email program. In the following journal, we have discussed the distinctive features, merits, and demerits of the latest mobile phone processors of different Tech companies.

A Comparative Study on the Recent Smart Mobile Phone Processors

This article proposes a unified power-flow controller (UPFC) to suppress subsynchronous resonance occurred in a hybrid power-generation system connected to an infinite bus through a series-capacitor compensated line. The hybrid power-generation system contains a steam-turbine generator (STG) and an offshore wind farm (OWF) based on doubly-fed induction generator (DFIG). The d – q axis equivalent-circuit model under three-phase balanced loading conditions is derived to establish the complete system model including the STG set, the DFIG-based OWF, the series-capacitor compensated line, the UPFC, etc. A damping controller of the proposed UPFC is designed by using pole-assignment approach based on modal control theory to effectively damp out unstable STG modes of the studied system. Both small-signal stability and transient simulation results of the studied system are systematically performed. The simulation results show that the proposed UPFC joined with the designed damping controller can effectively suppress unstable STG modes of the studied power system.

Damping of Subsynchronous Resonance in a Hybrid System With a Steam-Turbine Generator and an Offshore Wind Farm Using a Unified Power-Flow Controller

This paper proposes an algorithm for optimal placement of FACTS devices in transmission line to maintain the power system voltage stability and optimal sizing of the FACTS device. The aim of this paper is to improve voltage stability and reduce the total power losses. Here, voltage stability means no variation in the voltages of each bus beyond its boundaries and system stability is the ability of power system to recover the initial steady state after any deviation of the system’s operation. For this work, we presented the combined evolutionary algorithm i.e. Cuckoo Search (CS) and Evolutionary Programming (EP) algorithm to find the optimal location and optimal capacity to be placed at the location for FACTS device. Here, CS is used to find the optimal location of UPFC to be placed in the transmission line and EP algorithm is needed to compute the optimal capacity of corresponding FACTS device at the location. The capacity of the UPFC at that location depends on voltage deviation of the selected bus from slack bus, power loss, voltage instability and the insufficient reactive power in the power system. The presented technique helps in the optimal placement and optimal capacity of the FACTS device to be placed. Thus, the proposed method helps in the improvement of reactive power to meet the voltage stability and the reduction of the total power losses. A simulation on IEEE 30-bus reliability test system (RTS) justifies the reliability of the proposed method for real system applications concerning voltage stability improvement in power system.

/pdf/maintaining-voltage-stability-by-optimal-locating-and-sizing-jsdkyd3m17.pdf

Maintaining Voltage Stability by Optimal Locating and Sizing by Combined Evolutionary Algorithm

Series compensation in long transmission lines is an effective solution of enhancing power transfer capacity of Power System network In this paper, series passive compensation and shunt active compensation provided by static synchronous compensator (STATCOM) and other FACTS controllers connected at the electrical center of the transmission line are considered The presence of series capacitors has given rise to the phenomena Subsynchronous Resonance (SSR) But in few conditions such as in fault conditions, SSR phenomenon takes place which can damage the turbine generator shaft In this paper SSR phenomenon is studied with modified IEEE second benchmark model and various techniques has been developed for damping of SSR by adjusting the series compensation and using the FACTS controllers Results have been taken with the help of MATLAB simulation

Damping subsynchronous oscillations in power system using shunt and series connected FACTS controllers

The aim of this paper is to develop an effective method for solving matrix game with payoffs of trapezoidal fuzzy numbers (TrFNs). The method always assures that players’ gain-floor and loss-ceiling have a common TrFN-type fuzzy value and hereby any matrix game with payoffs of TrFNs has a TrFN-type fuzzy value. The matrix game is first converted to a fuzzy linear programming problem, which is converted to three different optimization problems, which are then solved to get the optimum value of the game. The proposed method has an edge over other method as this focuses only on matrix games with payoff element as symmetric trapezoidal fuzzy number, which might not always be the case. A numerical example is given to illustrate the method.

A Fast Approach to Solve Matrix Games with Payoffs of Trapezoidal Fuzzy Numbers

— The development of the modern power system has led to an increasing complexity in the study of power systems, and also presents new challenges to power system stability, and in particular, to the aspects of transient stability and small-signal stability. Transient stability control plays a significant role in ensuring the stable operation of power systems in the event of large disturbances and faults, and is thus a significant area of research. This paper investigates the improvement of transient stability of a two-area power system, using TCSC which is an effective FACTS (Flexible AC Transmission System) device. Simulations are carried out in Matlab/Simulink environment for the two-area power system model with TCSC to analyze the effects of TCSC on transient stability performance of the system. The performance of TCSC is compared with other FACTS devices such as Static Synchronous Series Compensator (SSSC), and Static Var Compensator (SVC). The simulation results demonstrate the effectiveness and robustness of the proposed TCSC on transient stability improvement of the system.

Effectiveness of FACTS Devices for Power System Stability Enhancement

The sub synchronous resonance (SSR) is a substantial problem in power system having a steam turbine generator connected to a series compensated transmission system. Flexible AC transmission systems (FACTS) controllers are widely applied to mitigate SSR. In this paper, a bus voltage and line current (BVLC) supplementary subsynchronous damping controller (SSDC) is proposed to alleviate subsynchronous resonance (SSR) and damping power system oscillations in a power system. Both eigenvalue investigation and time-domain simulation results verify that the proposed method can damp torsional oscillations of the power system with SVS bus voltage and line current (BVLC) supplementary controller. The results demonstrate that the proposed controller has a successful performance in minimizing the SSR. It is shown that the controller is able to stabilize all unstable modes. The study is performed on the system adapted from the IEEE first benchmark model. All the simulations are carried out in MATLAB/SIMULINK environment.

/pdf/ssr-alleviation-using-bvlc-supplementary-controlled-svs-of-3k3q25nvl8.pdf

Sanjiv Kumar

Papers

Damping subsynchronous oscillations in power system using shunt and series connected FACTS controllers

A Fast Approach to Solve Matrix Games with Payoffs of Trapezoidal Fuzzy Numbers

Effectiveness of FACTS Devices for Power System Stability Enhancement

SSR Alleviation using BVLC Supplementary Controlled SVS of Series Compensated Power System

Comparison of Various Auxiliary Signals for Damping Subsynchronous Oscillations Using TCR-FC