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Presence of shunt FACTS (Flexible Alternating Current Transmission System) device significantly affect the performance of protection system and may create security and reliability issues. This paper introduces a novel approach for zone identification in transmission line employing shunt FACTS devices such as Static Var Compensator (SVC) and Static Synchronous Compensator (STATCOM). The technique depends on the modified apparent impedance seen by the impedance relay for all possible operating conditions. In this technique the Support Vector Machine (SVM) is used for discriminating faulty zone (zone 1 or zone 2). In addition an optimization technique viz. Genetic Algorithm (GA) is used to optimize SVM parameters. A typical 230 kV system was simulated in PSCAD/EMTP software and the results show that the proposed scheme is secure, accurate and reliable under the wide variation in power system parameters like load angle, fault resistance, fault location, inception angle and compensation level. [ABSTRACT FROM AUTHOR]

This paper presents a novel Flexible AC Transmission Systems (FACTS) placement method based on mixed integer quadratically constrained programming (MIQCP). The method is capable of allocating both Static VAR Compensator (SVC) and Thyristor-Controlled Series Capacitor (TCSC) either separately or simultaneously, to determine concurrently their numbers, locations as well as sizes. The optimization objective is to maximize loadability and minimize compensation. The proposed MIQCP formulation partially incorporates key quadratic constraints, which were absent in mixed integer linear programming (MILP) placement methods reported in the past. The authors demonstrate significant improvements in accuracy over past MILP methods, with case studies presented on the simplified Southeast Australian network, and on a large scale real-world power system, Powerlink Queensland's HV transmission network, with 886 buses and 1087 branches. In addition, results and observations for simultaneous allocation of multiple TCSCs and SVCs in these networks are demonstrated in this paper. [ABSTRACT FROM AUTHOR]

• Categorization of FACTS devices as HSRF, MSRF, and LSRC devices by response speed. • Mathematical modelling for the coordination of MCR with SVC and FC. • Control strategy to enhance the compensation capacity of high response speed SVC. • Control strategy to enhance the low compensation speed of MCR and FC. • The proposed strategy is suitable for full range of compensation for power system. Traditional devices in flexible AC transmission system (FACTS) like magnetically controllable reactor (MCR), and fixed capacitors (FC) are less expensive and have medium or low response speed that can only provide excessive inductive or capacitive reactive power compensation. However, modern FACTS devices like static var compensators (SVC) are expensive and have high response speed which can provide limited inductive to capacitive reactive power compensation as compared to the MCR and FC. In addition, if there is no proper coordination between these traditional and modern FACTS devices they absorb each other's reactive power and may results in the decrease of compensation margin and wastage of the resources. Therefore, to make an effective use of these categories of FACTS devices in the existing power system, the coordination control that shares high speed and excessive compensation ability without wastage of resources is essential. This paper presents coordinated control of multi-FACTS devices to provide efficient reactive power compensation based voltage regulation. At first, the characteristics of various categorical FACTS devices are presented in relation to response speed by incorporating high speed response FACTS (HSRF), medium speed response FACTS (MSRF) and low speed response compensator (LSRC). Finally, the MCR with SVC and MCR with FC coordination controls have been developed sequentially with minimal efforts of compatibility issues and compensation speed while ensuring an increase in the reactive power reserves for the SVC. The simulation is carried out on PSCAD/EMTDC to test the coordination control efficiency of several three phase multi-FACTS devices with series and parallel configurations and validated on a modified IEEE 30 bus power system. The results show that multi-FACTS coordination control increases the SVC reserves and is promising in providing voltage regulation for the power system under various scenarios. [ABSTRACT FROM AUTHOR]

• This paper studies the effect of varying wind speed, replacement of Synchronous Generator with DFIG at various locations, and wind penetration with and without PSS, SVC and STATCOM. • The objective function for PSO selected as the real part and damping ratio of eigenvalue. This PSO is used for tuning the control parameter. • The transient and small signal stability carried out by using time domain simulation and eigenvalue analysis. • The effectiveness and robustness of proposed approaches are verified considering IEEE-14 system. In a power system with renewable energy sources, the Low-Frequency Oscillatory (LFO) modes arise due to the intermittent nature of wind power, loading and generating conditions. This is undesirable and results in system instability. If these LFO modes are not controlled, it may lead to a power interruption and results in unstable. The LFO modes are damped by Power System Stabilizers (PSS). However, it causes variation in voltage profile resulting in reduction instability of the system during large disturbances. In such cases, the flexible ac transmission system controllers are required. This paper presents and compares the PSS, Static synchronous Compensator (STATCOM) and Static Var Compensator (SVC) controller by replacing Synchronous Generator (SG) with same rated wind farm and various wind power penetration levels by considering system uncertainties such as wind speed. In this paper, a robust coordinated method is proposed using Particle Swarm Optimization (PSO) for optimizing parameters of controllers of PSS, SVC, and STATCOM. The real part and damping ratio of eigenvalues is the objective function for PSO and is formulated based on the small-signal and transient analysis. Controller locations are determined by the deterministic method, probabilistic method and power flow sensitivity analysis. An eigenvalue analysis approach based on the linearization of a nonlinear system using a state-space model is conducted to analyse the Small Signal Stability performance. Time-domain simulation is carried out for transient stability under large disturbance. The robustness and effectiveness of the proposed approaches for transient and small-signal stability are evaluated on the IEEE-14-bus system. The results reveal that the proposed location and optimized gain parameters for controllers effectively damped the LFOs. It also intensifies the transient capability under extreme disturbances and shows enhancement in system stability. [ABSTRACT FROM AUTHOR]