Controllable Reactor Research Articles

Fault component integrated impedance-based pilot protection scheme for EHV/UHV transmission line with thyristor controlled series capacitor (TCSC) and controllable shunt reactor (CSR)

This paper analyzes the fundamental frequency impedance characteristic of a thyristor controlled series capacitor (TCSC) and presents a novel transmission line pilot protection scheme based on fault component integrated impedance (FCII) calculated for a transmission line with TCSC and controllable shunt reactor (CSR). The FCII is defined as the ratio of the sum of the fault component voltage phasors of a transmission line with TCSC and CSR to the sum of the fault component current phasors where all the phasors are determined at both line’s terminals. It can be used to distinguish internal faults occurring on the line from external ones. If the fault is an external one the FCII reflects the line’s capacitive impedance and has large value. If the fault is an internal one on the line the FCII reflects the impedance of the equivalent system and the line and is relatively small. The new pilot protection scheme can be easily set and has the fault phase selection ability and also it is not affected by the capacitive current and the fault transition resistance. It is not sensitive to compensation level and dynamics of TCSC and CSR. The effectiveness of the new scheme is validated against data obtained in ATP simulations and Northwest China 750 kV Project.

Research on the High Leakage Reactance of the Superconducting Controllable Reactor

High leakage reactance of superconducting controlled the working principle and structure of the reactor were introduced Description and analysis of the three modes of operation of the superconducting coil of the secondary side. Three modes of operation of the secondary winding of the two superconducting windings are open, superconducting winding short-circuit superconducting windings open circuit, two superconducting windings are short-circuit. Through the design and calculation of the characteristics of a superconducting controllable reactor three modes of operation, and prospected for high-leakage reactance of superconducting controllable reactor advantages, characteristics and development prospects.

Simulation Research of Three-Phase Magnetic Controllable Reactor

A kind of new type three-phase magnetism valve type controllable reactor is proposed in this article, its structure and the principle are introduced. The article carried the electromagnetism analysis on the new type magnetism valve type controllable reactor, and established the three-phase magnetism valve type controllable reactor two-dimensional simulation model with Ansoft electric-magnetic field analysis software. Simulation results verified the feasibility of adjusting the reactor reactance smoothly by adjusting the thyristor's triggering angle. Lastly, it made an analysis about three-phase magnetism valve type controllable reactor's electromagnetism field distribution.

Overview of Power Controllable Reactor Technology

Consider the development status of controllable reactor, five types of power controllable reactors are introduced: mechanical controllable reactors, thyristor controllable reactor, magnetic saturation controllable reactor, transformertype Controllable reactor and superconducting-type controllable reactor. Finally, the development of power controllable reactor technologies is prospected.

可控电抗器的有限元分析

本文基于交流可控饱和电抗器的自励磁结构，建立了电抗器的有限元模型。以380 V/13A可控电抗器为研究对象，建立了可控电抗器磁场分布的ANSYS有限元模型。分析结果表明，在传统磁控电抗器的结构下的两个铁心柱小截面段的交替饱和，在小截面段附近铁心区域存在较大的横向磁场分量，增加了可控电抗器铁心和绕组附加损耗，可以通过对小截面进行了分段处理降低可控电抗器铁心和绕组的部分附加损耗。 Model of reactor based on the Finite Element Method (FEM) is built on base of a controllable reactor model with self-excitation structure. ANSYS simulation model of a 380 V/13Acontrollable reactor is built. The results show that the two small section segments of the cores of traditional controllable reactor saturate by turns, it increases the consumption of the cores and windings of controllable reactor, by separating the cores can it reduce the consumption of the controllable reactor.

Analysis of Reactor Magnetic Circuit Based on ANSYS Command Flow

Controllable reactor is the common equipment in the modern power system, which plays an important role in voltage control and reactive power compensation. The core structure of reactor effects the magnetic field distribution in the core and the loss of reactor. In this paper, the models of two kinds of classic reactors are built by the ANSYS command flow method, and explain the differences between magnetic valve controllable reactor and common reactor. This paper points out the advantages of command flow compared with the graphical user interface and the important role of ANSYS finite element analysis in the structural design of reactor.

Boundary element methods for magnetostatic field problems: a critical view

For the solution of magnetostatic field problems we discuss and compare several boundary integral formulations with respect to their accuracy, their efficiency, and their robustness. We provide fast boundary element methods which are able to deal with multiple connected computational domains, with large magnetic permeabilities, and with complicated structures with small gaps. The numerical comparison is based on several examples, including a controllable reactor as a real-world problem.

A novel large-capacity controllable reactor based on a transformer with voltage source inverter load

In this article a novel controllable reactor based on regulating the transformer's primary equivalent impedance by controlling its secondary voltage source inverter load is proposed. When the secondary current of a transformer is forced to be proportional to and in inverse phase with its primary current, the primary side of the transformer exhibits a linear adjustable reactance with respect to the proportion coefficient. The voltage source pulse width modulation (PWM) inverter connected to the secondary side of the transformer provides the required secondary current. In order to realise a large-capacity reactor, a transformer with multiple secondary windings is used to reduce the capacity requirement of each PWM inverter. A large-capacity (800 kVA) prototype is fabricated. The experimental results verify the characteristics of the novel controllable reactor – linear reactance tuning, few harmonics and fast response.

Photochemistry in Photonic Crystal Fiber Nanoreactors

We report the use of a liquid-filled hollow-core photonic crystal fiber (PCF) as a highly controlled photochemical reactor. Hollow-core PCFs have several major advantages over conventional sample cells: the sample volume per optical path length is very small (2.8 nL cm(-1) in the fiber used), long optical path lengths are possible as a result of very low intrinsic waveguide loss, and furthermore the light travels in a diffractionless single mode with a constant transverse intensity profile. As a proof of principle, the (very low) quantum yield of the photochemical conversion of vitamin B(12), cyanocobalamin (CNCbl) to hydroxocobalamin ([H(2)OCbl](+)) in aqueous solution was measured for several pH values from 2.5 to 7.5. The dynamics of the actively induced reaction were monitored in real-time by broadband absorption spectroscopy. The PCF nanoreactor required ten thousand times less sample volume compared to conventional techniques. Furthermore, the enhanced sensitivity and optical pump intensity implied that even systems with very small quantum yields can be measured very quickly--in our experiments one thousand times faster than in a conventional cuvette.

The results of systems tests of the 500 kV busbar controllable shunting reactor in the Tavricheskaya substation

The results of systems tests of the 500 kV busbar magnetization-controllable shunting reactor (CSR), set up in the Tavricheskaya substation, including measurements of the quality of the electric power, the harmonic composition of the network currents of the reactor for different values of the reactive power consumed, the determination of the regulating characteristics of the reactor, the speed of response of the shunting reactor in the current and voltage stabilization modes, and also the operation of the reactor under dynamic conditions for different perturbations, are presented. The results obtained are analyzed.

Kinetic measurement of biological oxidation of ferrous iron at low ferric to ferrous ratios in a controlled potential batch reactor

Traditionally, the kinetics of microbial ferrous iron oxidation have been studied in continuous or in batch culture. Both methods have drawbacks: in continuous culture experiments have to be repeated at a number of dilution rates to cover the entire spectrum of ferrous to ferric ratios, which is time-consuming. Furthermore, experiments at very low ferric-to-ferrous ratios require high dilution rates which are close to or exceed those at which wash-out occurs. In batch experiments, on the other hand, the prevalent ferric to ferrous ratio rapidly changes due to substrate depletion while the microbial population continually grows, making determination of specific momentary rates difficult. The present paper describes initial work with a novel device, the Redostat™, which allows careful electrochemical control of ferric to ferrous ratio in a batch reactor. A culture of Leptospirillum ferriphilum was grown at 35 °C and 5 g dm − 3 total iron by maintaining the ferric to ferrous ratio at 0.17, 0.51 and 1.65 (corresponding to redox potentials of 419, 452 and 482 mV vs. Ag/AgCl), respectively. The correlation of data obtained from off-gas and current measurements was excellent, and fitted Monod kinetics with ferric inhibition. A hitherto unobserved effect indicates the onset of ferric iron inhibition at the low redox potentials employed here. It was also noted that the biomass concentration has an effect on the biomass specific ferrous iron consumption rate and the biomass yield on ferrous iron.

Relay protection and automatics of a 500 kV linear controllable shunting reactor

Based on experience in the design and calculations of regimes, the relay protection and automatic of a 500-kV bias-controlled linear shunting reactor are described.

Comparison of dissolution under oxic acid drainage conditions for eight sedimentary and hydrothermal pyrite samples

The abiotic oxidative dissolution behaviors of eight natural pyrite samples, five sedimentary and three hydrothermal, from various geological environments were compared under oxic conditions at pH 3 and 6 in a highly controlled batch reactor dissolution system. The three sedimentary pyrite samples associated with coal had greater specific surface areas and also exhibited greater apparent dissolution rates and extent than the other two sedimentary and three hydrothermal samples under both pH conditions. However, after normalizing for surface area, the dissolution rate constants for the different pyrite samples were similar; the greatest difference was between the two non-coal sedimentary pyrite samples. Pyrite morphology and the presence of trace metals could contribute to the differences in dissolution behavior as reflected in the normalized dissolution rates. The sulfur:iron ratio observed in the aqueous solution at pH 3 increased with time, but was always less than 2.0 (predicted from the stoichiometry of dissolution) for all the pyrite samples during the 24-h experimental duration. This can be explained by the disproportionation dissociation of thiosulfate, an initial product of pyrite dissolution, to elemental sulfur and sulfate which does not occur in a 1:1 ratio. The results of this work indicate the importance of extracting and using the specific pyrite(s) relevant to particular mining areas in order to understand pyrite dissolution rates and the influence of environmental conditions on those rates.

Intentionally patterned and spatially non-uniform film profiles in chemical vapor deposition processes

Situations where it is desirable to control a chemical vapor deposition reactor to a spatially non-uniform film profile are presented in the context of a planetary reactor system for SiC CVD and a highly controllable reactor system designed for single-wafer combinatorial CVD processing. We focus on reactor designs and operation methods that enable deposition of spatially graded films for combinatorial studies, and on identifying and driving planetary CVD systems to a specific spatially non-uniform deposition rate profile. Known as a “Nearest Uniformity Producing Profile” (NUPP), these target profiles lead to a natural criterion for film uniformity control under wafer rotation.

The operating principles, main characteristics, and prospects of usage of controllable reactors in electric circuits

Static controllable electromagnetic reactors of different types with distinctive technical characteristics are described in the paper. The main analytical equations for designing magnetic construction elements are given. Methods are shown for the improvement of the characteristics of fast-acting magnetic reactors and the broadening of the regulating diapason without increasing the high-current harmonics by changing the construction of the magnetic reactor. The limiting of the current by a controllable reactor in the short circuit mode is also given.

The design and construction of a controllable reactor with a HTS control winding

Reactive power compensation is vital for obtaining efficient operation of long transmission power lines or cables. The need of reactive power changes with the load of the transmission line. Discrete units of conventional reactors are therefore switched in and out in order to obtain more efficient reactive power compensation. A continuous reactive compensation will reduce the transmission losses and increase the transmission capacity of active power. We have designed and constructed a one phase small scale prototype of a controllable shunt reactor with a high temperature superconducting control winding. The reactor consists basically of two windings and an iron core. The control winding is placed so that it generates a DC magnetic field perpendicular to the main AC magnetic field. Thus the DC current in the control winding can control the direction of the magnetization of the iron core and thereby the reactance of the reactor. Such a control winding will have low losses and give the reactor a large dynamic range. For this small scale reactor we found that the reactive power could be varied with a factor six. We have demonstrated the feasibility to design large scale controllable shunt reactors with large dynamic range and low losses utilizing a control winding made of a high temperature superconductor.

Magnetic circuit for a controllable reactor

Reactive power compensation is vital for obtaining efficient operation of long transmission power lines or cables. A controllable shunt reactor that controls the transmission of power by continuous reactive power compensation will reduce the transmission losses and increase the transmission capacity of active power. We show that the saturation phenomena of iron and the high current density of a high-temperature superconductor can be utilized to design controllable reactors with large dynamic range, low losses, and limited harmonic distortion. We have designed and constructed a small-scale prototype of a controllable shunt reactor with a high-temperature superconductor control winding. We present a simple model of the magnetic circuit of the controllable reactor and we compare calculations from the model to experimental measurements on the controllable reactor

Development of a spatially controllable chemical vapor deposition reactor with combinatorial processing capabilities

Most conventional chemical vapor deposition (CVD) systems do not have the spatial actuation and sensing capabilities necessary to control deposition uniformity or to intentionally induce nonuniform deposition patterns for single-wafer combinatorial CVD experiments. In an effort to address these limitations, a novel CVD reactor system has been developed that can explicitly control the spatial profile of gas-phase chemical composition across the wafer surface. This paper discusses the construction of a prototype reactor system featuring a three-zone, segmented showerhead design. Experiments are performed to assess the ability of this reactor system to deposit tungsten films by the hydrogen reduction process; segment-to-segment process recipes are controlled to deposit spatially nonuniform W films. The capabilities of this reactor system for materials discovery research are discussed.

A pulsed light reactor for molecular weight control in free-radical polymerization

A new controlled polymerization reactor is introduced. The reactor design is based on the principles of pulsed initiation polymerization. The 1 l reactor is equipped with a high-voltage UV-stroboscope, the frequency of which can be raised up to 250 Hz. In this reactor pulsed initiation polymerizations of n-butyl acrylate were performed. Results indicate that the use of high pulse frequencies in this set-up may resolve problems associated with chain transfer to polymer in the determination of propagation rate coefficients for acrylates at temperatures above 30 °C.

Simulation‐based design and experimental evaluation of a spatially controllable CVD reactor

AbstractMost conventional chemical vapor deposition (CVD) systems do not have the spatial actuation and sensing capabilities necessary to control deposition uniformity, or to intentionally induce nonuniform deposition patterns for single‐wafer combinatorial CVD experiments. In an effort to address these limitations, a novel CVD reactor system has been developed that can explicitly control the spatial profile of gas‐phase chemical composition across the wafer surface. This paper discusses the simulation‐based design of a prototype reactor system and the results of preliminary experiments performed to evaluate the performance of the prototype in depositing tungsten films. Initial experimental results demonstrate that it is possible to produce spatially patterned wafers using a CVD process by controlling gas‐phase reactant composition, opening the door to a new class of flexible and highly controllable CVD reactor designs. © 2005 American Institute of Chemical Engineers AIChE J, 51:572–584, 2005