Voltage Stability Analysis of Grid-Connected Wind Farms with FACTS: Static and Dynamic Analysis

Recently, analysis of some major blackouts and failures of power system shows that voltage instability problem has been one of the main reasons of these disturbances and networks collapse. In this paper, a systematic approach to voltage stability analysis using various techniques for the IEEE 14-bus case study, is presented. Static analysis is used to analyze the voltage stability of the system under study, whilst the dynamic analysis is used to evaluate the performance of compensators. The static techniques used are Power Flow, V–P curve analysis, and Q–V modal analysis. In this study, Flexible Alternating Current Transmission system (FACTS) devices- namely, Static Synchronous Compensators (STATCOMs) and Static Var Compensators (SVCs) - are used as reactive power compensators, taking into account maintaining the violated voltage magnitudes of the weak buses within the acceptable limits defined in ANSI C84.1. Simulation results validate that both the STATCOMs and the SVCs can be effectively used to enhance the static voltage stability and increasing network loadability margin. Additionally, based on the dynamic analysis results, it has been shown that STATCOMs have superior performance, in dynamic voltage stability enhancement, compared to SVCs

Comparison of Stabilization Methods for Fixed-Speed Wind Generator Systems

Static Synchronous Compensator (STATCOM), Pitch control system, Braking Resistor (BR), and Superconducting Magnetic Energy Storage (SMES) have recently been reported as stabilization methods for fixed-speed wind generator systems. although the individual technologies are well documented, a comparative study of these systems has not been reported so far. This paper aims to fill in the gap, and provides a comprehensive analysis of these stabilization methods for fixed-speed wind generator systems. The analysis is performed in terms of transient stability enhancement, controller complexity, and cost. a novel feature of this work is that the transient stability analysis of wind generator system is carried out considering unsuccessful reclosing of circuit breakers. Simulation results demonstrate that the SMES is the most effective means of transient stability enhancement and minimization of both power and voltage fluctuations, but it is the most expensive device. The STATCOM is a cost-effective solution for transient stability enhancement and minimization of voltage fluctuations. The BR is the simplest in structure and a cost-effective solution for transient stability enhancement. The pitch controller is the cheapest one, but its response is much slower than that of other devices

Resource aware wind farm and D-STATCOM optimal sizing and placement in a distribution power system

Doubly fed induction generators (DFIG) based wind farms are capable of providing reactive power compensation. Compensation capability enhancement using reactors such as distributed static synchronous compensator (D-STATCOM) while connecting distribution generation (DG) systems to grid is imperative. This paper presents an optimal placement and sizing of offshore wind farms in a coastal distribution system that is emulated on an IEEE 33 bus system. A multi-objective formulation for optimal placement and sizing of the offshore wind farms with both the location and size constraints is developed. Teaching learning algorithm is used to optimize the multi-objective function constraining on the capacity and location of the offshore wind farms. The proposed formulation is a multi-objective problem for placement of the wind generator in the power system with dynamic wind supply to the power system. The random wind speed is generated as the input and the wind farm output generated to perform the optimal sizing and placement in the distributed system. MATLAB based simulation developed is found to be efficient and robust

Power System Loading Margin Enhancement by Optimal STATCOM Integration:a case study

Safe and secure network operation with acceptable voltage level has become a challenging task for utilities requiring corrective measures to be implemented. Network upgrades using Flexible Alternating Current Transmission System devices are being considered to serve this purpose. To this end, static loading margin enhancement by optimal static synchronous compensator (STATCOM) allocation to enhance the power transfer capability with minimal voltage variation is presented. Maximum loadability is formulated as an optimization problem, subjected to voltage and small-signal stability constraints. Stability indices are presented and incorporated with the optimization problem to ensure secure operation under maximum loading. The scheme is executed with the IEEE system and an Indian utility network. Improved voltage regulation with different loading condition was achieved for both test networks, with the service rendered by the optimally placed STATCOM. Moreover, it facilitates an additional 50% capacity release in both test systems for hosting the active power and loads

A hybrid algorithm for voltage stability enhancement of distribution systems

This paper presents a hybrid algorithm by applying a hybrid firefly and particle swarm optimization algorithm (HFPSO) to determine the optimal sizing of distributed generation (DG) and distribution static compensator (D-STATCOM) device. A multi-objective function is employed to enhance the voltage stability, voltage profile, and minimize the total power loss of the radial distribution system (RDS). Firstly, the voltage stability index (VSI) is applied to locate the optimal location of DG and D-STATCOM respectively. Secondly, to overcome the sup-optimal operation of existing algorithms, the HFPSO algorithm is utilized to determine the optimal size of both DG and D-STATCOM. Verification of the proposed algorithm has achieved on the standard IEEE 33-bus and Iraqi 65-bus radial distribution systems through simulation using MATLAB. Comprehensive simulation results of four different cases show that the proposed HFPSO demonstrates significant improvements over other existing algorithms in supporting voltage stability and loss reduction in distribution networks. Furthermore, comparisons have achieved to demonstrate the superiority of HFPSO algorithms over other techniques due to its ability to determine the global optimum solution by easy way and speed converge feature

VAr Compensation Based Stability Enhancement Of Wind Turbine Using STATCOM

Maintenance of power system stability becomes vital during disturbances like faults, contingency etc. This work deals with a novel priority oriented optimal reactive power compensation of Doubly-Fed Induction Generator (DFIG) based wind turbine using Static Synchronous Compensator (STATCOM). A multi-objective problem will be formulated to maintain voltage within its tolerance levels using Voltage Severity Index (VSI) and to mitigate low frequency oscillations by using Transient Power Severity Index (TPSI) during post-fault conditions. An optimal solution to this proposed problem will be obtained using Fuzzy Logic. In order to justify the proposed methodology it is simulated and tested using 2 MW DFIG with MATLAB- Simulink.nbs