Analysis and control of STATCOM/SMES compensator in a load variation conditions

The utilization of Flexible AC Transmission System (FACTS) devices in a power system can potentially overcome limitations of the present mechanically controlled transmission system. Also, the advanced technology makes it possible to include new energy storage devices in the electrical power system. The integration of Superconducting Magnetic Energy Storage (SMES) into Static Synchronous Compensator (STATCOM) can lead to increase their flexibility to improve power system dynamic behavior by exchanging both active and reactive powers with power grids. This paper describes structure and behavior of STATCOM/SMES compensator in power systems. A control strategy based on direct Lyapanov method for compensator is used. Moreover, the performance of the STATCOM/SMES compensator in a load variation condition is evaluated by PSCAD/EMTDC software in test system. Also, SMES capacity effects on integrated compensator are investigated

Dynamic Modeling and Simulation of a STATCOM/SMES Compensator in Power Systems

The advent of Flexible AC Transmission Systems (FACTS) is giving rise to a new family of electronic equipment emerging to controlling and optimizing the performance of power system, e.g. STATCOM. Static synchronous compensator (STATCOM) is one of the most widely used FACTS devices. This paper presents the integration of STATCOM coupled with superconducting magnetic energy storage (SMES) device in order to provide power oscillation damping in power systems. The additional of energy storage allows the combined compensator to exchange both reactive and active power with the ac network and also capability of the STATCOM is enhanced. This paper describes the structure and characteristics of STATCOM/SMES. In addition, using a proper control scheme, STATCOM/SMES is tested on an IEEE 3-bus system and more effective performance of the presented STATCOM/SMES compensator is evaluated with alone STATCOM through the dynamic simulation by using PSCAD/EMTDC software

Dynamic Modeling and Simulation of a STATCOM/SMES Compensator in Power Systems

The advent of Flexible AC Transmission Systems (FACTS) is giving rise to a new family of electronic equipment emerging to controlling and optimizing the performance of power system, e.g. STATCOM. Static synchronous compensator (STATCOM) is one of the most widely used FACTS devices. This paper presents the integration of STATCOM coupled with superconducting magnetic energy storage (SMES) device in order to provide power oscillation damping in power systems. The additional of energy storage allows the combined compensator to exchange both reactive and active power with the ac network and also capability of the STATCOM is enhanced. This paper describes the structure and characteristics of STATCOM/SMES. In addition, using a proper control scheme, STATCOM/SMES is tested on an IEEE 3-bus system and more effective performance of the presented STATCOM/SMES compensator is evaluated with alone STATCOM through the dynamic simulation by using PSCAD/EMTDC software

Dynamic Performance of a Static Synchronous Compensator with Energy Storage

This paper discusses the integration of a static synchronous compensator (STATCOM) with an energy storage system in damping power oscillations. The performance of the STATCOM, a self-commutated solid-state voltage inverter, can be improved with the addition of energy storage. In this study, a 100 MJ SMES coil is connected to the voltage source inverter front-end of a STATCOM via a DC-DC chopper. The dynamics of real and reactive power responses of the integrated system to system oscillations are studied using an electromagnetic transient program PSCAD TM /EMTDC TM and the findings are presented. The results show that, depending on the location of the STATCOM-SMES combination, simultaneous modulation of real and reactive power can significantly improve the performance of the combined compensator. The paper also discusses some of the control aspects in the integrated system

Short circuit study of fixed speed wind turbines with STATCOM in distribution networks

The increased penetration of wind farm in distribution networks has brought changes in the performance of the whole system. Such disadvantages when connecting one of these distributed generation sources is reduced voltage and power stability of the AC network. This phenomena can cause the connected electricity consumers to suffer from disturbances. This paper investigates the use of a static synchronous compensator (STATCOM) to improve the short circuit current contribution in the network which will include balanced and unbalanced faults. The wind farm is equipped with fixed-speed wind turbines driving squirrel-cage induction generators. The IEEE 30-bus distribution test system is used to see the performance of the system under distribution level. Simulation studies are carried out in the DIgSILENT software

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

Two-leg three-phase inverter control for STATCOM and SSSC applications

Flexible ac transmission systems (FACTS) devices are attracting an increasing interest both in power system academic research and in electric utilities for their capabilities to improve steady-state performance as well as system stability. Several converter topologies for FACTS applications have been proposed in the recent literature, even if those based upon voltage source inverters (VSI) seem to be more attractive due to their intrinsic capability to rapidly respond to network changes such as perturbations subsequent to a fault and their property of being immune to resonance problem. In this paper, a new topology for inverter-based FACTS is proposed. This configuration, employing a two-leg three-phase inverter is employed for both series and parallel-connected reactive power compensators. The converter utilizes a modular topology for allowing a satisfaction of electronic components rating. A control strategy based on variable structure control technique with sliding mode is employed to track appropriate reference quantities. Design and control, as well as good tracking performances, are also verified through numerical simulations

Energy and voltage management methods for multilevel converters for bulk power system power quality improvement

Electric arc furnaces (EAFs) are prevalent in the steel industry to melt iron and scrap steel. EAFs frequently cause large amplitude fluctuations of active and reactive power and are the source of significant power quality disturbances. Also EAFs comprise a major portion of industrial loading on the bulk power system. Typically, a static VAR compensator (SVC) or Static Synchronous compensator (STATCOM) are use to provide the reactive power support in order to alleviate the fluctuations in voltage at PCC. Static Synchronous Compensators (STATCOMs) provide a power electronic-based means of embedded control for reactive power support. Integrating an energy storage system (ESS) such as large capacitors with the STATCOM will improve the device performance to have active power controllability as well as the reactive power. A cascaded multilevel STATCOM has been utilized in order to compensate for all the fluctuations caused by an EAF both in the RMS of the voltage at PCC and also the active power generation. Designing a sophisticated controller, it is possible to get the STATCOM track the variations of active power in load. Therefore, the generator does not need to produce the random active power demanded by the load --Abstract, page iv

Full body harness

The full body safety harness is a key part of an active fall arrest system. The harness serves two purposes, first, distributing fall forces safely across a worker's body in the event of a free fall, and second, providing freedom of movement sufficient to allow the worker to effectively perform his or her job. The complete body harness incorporates the characteristics of a sit harness that supports the hips and upper legs as well as a chest harness that supports the chest and shoulders. The complete body structure includes the human torso when correctly used and helps to keep it upright during a fall case

Power Converters and Power Quality

This paper discusses the subject of power quality for power converters. The first part gives an overview of most of the common disturbances and power quality issues in electrical networks for particle accelerators, and explains their consequences for accelerator operation. The propagation of asymmetrical network disturbances into a network is analysed. Quantitative parameters for network disturbances in a typical network are presented, and immunity levels for users' electrical equipment are proposed. The second part of this paper discusses the technologies and strategies used in particle accelerator networks for power quality improvement. Particular focus is given to networks supplying loads with cycling active and reactive power.Comment: 26 pages, contribution to the 2014 CAS - CERN Accelerator School: Power Converters, Baden, Switzerland, 7-14 May 201