Rectifier Installations Research Articles

Optimization of Rectifiers in Firefighting Monitors Used in UHV Fire Safety Applications

An electric power system is an important factor in national economic development. However, as an electric power system requires more electric equipment in its operation process, it is prone to short circuits, faults and other problems, which can lead to fires. To help prevent fires in such power systems, the hydraulic performance of the existing firefighting monitor should be optimized. A rectifier is an important structure which affects the performance of the firefighting monitor. In this paper, numerical simulations based on CFD (computational fluid dynamics) are carried out to analyze the fluid flow inside firefighting monitors with five different rectifier structures. In addition, the effects of rectifier structure on both the turbulent kinetic energy and axial velocity of the fluid inside the firefighting monitor are analyzed. The results show that rectifier installation can reduce the turbulent energy of the inlet and outlet of the firefighting monitor and improve the axial velocity distribution inside the firefighting monitor. Specifically, a forked row rectifier arrangement can significantly improve the effect of flow stabilization. However, there are limits to improving rectifier stabilization performance by changing the number of blades, as too many blades can cause reverse direction flow and large pressure losses.

Determination of voltage at the rectifier installation of the electric locomotive VL-80K for each position of the controller driver's

The object of research is the electrical processes in the control system of the traction drive of the electric locomotive VL-80K (Russia). To improve the accuracy of its mathematical model, it is necessary to use the values of the parameters determined during experimental studies of the traction drive control system. In particular, it is important to use in the traction drive model the value of the voltages on the arms of the rectifier installation of the electric locomotive, taking into account the position of the driver's controller. The complexity of the simulation lies in the fact that the reference does not provide the value of the voltage on the arms of the rectifier for each position of the driver's controller, which makes it difficult to verify the resulting model. A scheme for measuring the voltage value on the arms of the rectifier installation of an electric locomotive for each position of the position of the driver's controller is proposed. On its basis, a simulation model is developed in the MATLAB software environment. The simulation model implements an algorithm for closing the contactors of the electric group contactor for each position of the position of the driver's controller. Approbation of the voltage measurement technique was carried out on an electric locomotive of the VL-80K series during a trip on the Darnytsia-Myronivka section (Ukraine). Comparison of the voltage values on the arms of the rectifier installation, obtained experimentally, with the passport data showed that the measurement error was 0.5 %. In addition, the experimental results showed that the voltages on the arms of the rectifier for paired positions of the position of the driver's controller are the same, for odd ones they are different. Therefore, when simulating the operation of the traction drive control system, the voltage values on different arms of the rectifier installation were taken separately. Comparison of the simulation results for the nominal mode with passport data showed that for this mode the measurement error was 3.78 %. For all others, it did not exceed 5 %.

Determination of Voltage at the Rectifier Installation of the Electric Locomotive Vl-80K for Each Position of the Controller Driver’s

Determination of Voltage at the Rectifier Installation of the Electric Locomotive Vl-80K for Each Position of the Controller Driver’s

Method of calculating the distortion coefficient sinusoidality of the voltage curve created by three-phase straight lines

The existing calculation methods in various sources represent rectifier installations as sources of higher harmonics. In this case, the current value of the primary winding of the transformer in the form of rectangles is decomposed into a Fourier series and harmonic components of the current are obtained, except for the main harmonic higher 5, 7, 11, 13, 17, 19 The amplitudes of the current of the higher harmonics are multiplied by the inductive resistances of the supply network corresponding to the frequencies, the results are squared and summed up. Obviously, all terms are of equal magnitude, since with an increase in the harmonic number, its amplitude decreases by n times compared to the first harmonic, while the frequency and inductive resistance increase by the same number of times. The non-sinusoidal coefficient Ku is defined as the ratio of the square root of the sum to the magnitude of the phase voltage. The disadvantage of determining Ku is some arbitrariness in the number of harmonics taken into account. If we take, for example, 9 harmonics, we get Ku = 7.22%, if 4 harmonics, then Ku = 4.81%. When the current of the primary winding of the transformer flows, the voltage amplitude on the substation tires decreases by only 1.9 V. At the same time, the coefficient of non-sinusoidality cannot be equal to 7.22%. In all literature sources, when calculating current harmonics, there are no recommendations for which harmonic numbers should be installed at the substation resonant filters. It is no coincidence that in the new GOST-2013, the value of the distortion coefficient of the sinusoidal voltage curve K(U is calculated as a percentage as a result of the i-th observation according to the formula, (that is, no calculation is made by current harmonics). In this paper, another approach is made to determine the distortion coefficient of the sinusoidal voltage curve. Rectifier installations are not sources of harmonics, but are electrical receivers with a nonlinear characteristic of electric current consumption, while the shape of the sinusoid curve of the supply voltage is distorted. This distorted sine wave is the source of the higher harmonics, which in this paper is decomposed into a Fourier series, while the calculation of the integral functions of the coefficients of the Fourier series is performed in the Mathcad program. The solution is made for three rectifier circuits. Harmonics for the installation of resonant filters are determined. As a result, a developed method is proposed for calculating the higher voltage harmonics and determining the distortion coefficient of the sinusoidal voltage curve based on the Fourier series expansion of the distorted voltage sine curve during operation of three-phase uncontrolled rectifiers.

Increasing Copper Production in Electrochemical Plants Using New Small Transformer–Rectifiers in Parallel With Existing Power Rectifiers

The production of copper in electrochemical plants requires a large amount of dc current to obtain the desired copper product output. The dc current is supplied by high-current thyristor-based controlled rectifiers. Many copper plants use rectifier systems designed with two or more similar transformer-rectifiers connected in parallel to obtain the desired dc current output. Parallel rectifier systems may use 12 or 24 pulses depending on rated values of dc current. To maximize copper production when higher quality mineral is being processed, the dc current needs to be increased to values that exceed the designed rated output value of the transformer-rectifier. To solve this problem, a smaller supplementary low-current rectifier can be connected in parallel with the existing rectifiers to achieve the desired dc current output. This solution proves to be economical compared with other alternatives such as increasing the number of cells in the process or replacing the existing transformer-rectifiers with larger ones. This solution has been implemented in several copper plants with satisfactory results. As an example, a 2 x 25 kA 12-pulse rectifier installation was modified to a 60-kA 18-pulse rectifier installation by adding a 10-kA auxiliary transformer-rectifier in parallel with the existing rectifiers. This modified design has continuously and successfully operated for the past five years. This paper will describe the requirements for determining if an auxiliary transformer-rectifier is the best solution for increasing the total dc current capacity.

New life for old thyristor power rectifiers using contemporary digital control

This paper presents information on a control and monitoring system retrofit of two unreliable 1978 14 MW rectifiers used in a sodium chlorate plant. Reasons for the upgrade and expectations of the new system are discussed. Alternate solutions considered and the rationale supporting the choices made are reviewed. The paper summarizes the project from the initial investigation through the design process and selection of equipment. Justification of the expenditure, issues of mating old and new equipment, problems overcome during the implementation, and the lessons learned are described. In closing, the suitability of this approach for other rectifier installations is addressed.

On the Interaction Between Power System Configuration and Industrial Rectifier Harmonic Interference: A Practical Case Study

Department of Electrical and Computer Engineering A severe interference problem caused by a large rectifier installation is studied. The interaction between harmonic emission level and power system impedance matching is described. An elegant solution involving corrective measures on each of the plants: customer, power system and communication circuits, are proposed. The dangers of creating new problems with single approaches is stressed out, and the use of power current phase angles is illustrated in the analysis.

On the Interaction Between Power System Configuration and Industrial Rectifier Harmonic Interference: A Practical Case Study

A severe interference problem caused by a large rectifier installation is studied. The interaction between harmonic emission level and power system impedance matching is described. An elegant solution involving corrective measures on each of the plants???customer, power system and communication circuits???are proposed. The dangers of creating new problems with single approaches are stressed, and the use of power current phase angles is illustrated in the analysis.

One Year Operating Experience of Large Electrochemical SCR Rectifiers

After more than one year of successful operation, the design and performance of a 52.5 MW thyristor controlled rectifier installation in a chlor-alkali plant are reviewed. Procedures for final checkout of the installation before plant startup as well as field modifications made to the equipment are discussed. Maintenance procedures are outlined and advantages of thyristor controlled rectifiers are detailed. Power factor and harmonic considerations are also presented.

Design and Specification Considerations for Construction of Large Industrial Rectifiers and Their Associated Facilities

Proper preparation of specifications is essential to obtain competitive bids for purchase and installation of large industrial rectifiers and associated facilities. Specification requirements for a power rectifier installation are presented. The article discusses the development of design specifications for purchase of the rectifier equipment, considerations in selection of a supplier, design of the dc bus system for connecting the rectifier to the load, and preparation of installation specifications. Also included is an example of how the computer may be used to determine optimum bus bar material. A sample problem is included.

Committee Provides Opportunity for Coordination of Corrosion Control

As our country grows and its engineers develop new concepts and materials to prolong the life of buried metallic structures, we all should be aware and ready to reap the benefits. With the ever increasing development and use of underground structures, the chances of electrolytic corrosion causing damage also increases. The application of cathodic protection with rectifier installations is becoming more economical and popular with the larger underground users. This technique need not cause stray current damage to other underground structures if adequate coordination is available to all underground users.

Circuit calculations for rectifier locomotives and motor-coaches

The increasing use of rectifier locomotives and motor-coaches has focused attention on the limitations of accepted rectifier theory in the calculation of performance of bi-phase and single-phase bridge-connected rectifier circuits. Most industrial rectifier installations exceeding a few kilowatts in rating are supplied from a 3-phase system, and are designed to operate with 6- or 12-phase output on the d.c. side, while sometimes in very large installations it is necessary to operate with up to 72-phase output. In these conventional multi-phase equipments the ripple current, which is associated with undulations in the output voltage, is superimposed on the output direct current, but is sufficiently small to permit, for the purpose of calculation, the assumption of a d.c. circuit of infinite inductance. This assumption leads to considerable simplification of the theory. Unfortunately it is not tenable in the circuits discussed in the paper, as it is found that the presence of the ripple current in the d.c. circuit has a profound effect on the operation of the whole equipment.The paper outlines the calculations for bi-phase and bridge circuits, based on the accepted ‘infinite inductance’ theory, and derives the direct voltage at the motor, ripple current in the motor circuit, power factor in the a.c. supply, harmonic currents in the a.c. supply and other related quantities. The inaccuracies in the results of these calculations are pointed out.A description follows of a new approach to rectifier problems, by means of which solutions to both transient and steady-state problems can be obtained, taking proper account of resistances, inductances and capacitances in all parts of the circuit. The problems are treated as circuit problems, the equilibrium equations being established in terms of mesh currents and expressed as simultaneous first-order differential equations. These are solved by means of a digital electronic computer, Deuce, whose logical facilities are used to take account of the valve action of the rectifying elements.Results of calculations are supported by tests which were carried out in conjunction with British Railways on the Lancaster-Morecambe-Heysham section. A description of this electrification has appeared elsewhere.12 The operation of rectifier locomotives is discussed in the light of further calculations based on variations of a typical design.

Casing Corrosion in the Hugoton Gas Field★

Abstract A casing leak survey in the Hugoton Gas Field was made to obtain information with which the casing corrosion problem could be evaluated and the most severely affected areas located. It was determined that leak frequency was relatively low but that leaks usually resulted in decreased deliverability or loss of the well. Because the pool is expected to be productive for another 30 years, the seriousness of the problem was not reflected entirely by current leak frequency. Work to date indicates current application based on indications derived from surface potential measurements is sufficient to protect the wells and that the required current is obtainable from galvanic anodes. This latter fact is important because each well is located in the center of a section. Interference from rectifier installations has been found in the field, presenting a new problem in efforts to protect casing cathodically from corrosion. 8.4.3

Application of Cathodic Protection to 48 Well Casings And Associated Production Facilities at Waskom Field

Abstract Casing failures caused by external corrosion attack led to an engineering study to obtain design data and costs for a multiple rectifier type cathodic protection system for 48 wells. This protective system was subsequently installed in an effort to prevent further costly casing repairs. Difficulties encountered in obtaining the desired current drain of 1.5-2.0 amperes from each well and solutions to these problems are discussed. In final form the multiple rectifier installation provided all protective current for approximately 75 percent of the wells, while magnesium anodes were used exclusively or in supplement to rectifier drainage for the remainder. All of the coated gas lines, an appreciable portion of the bare oil gathering lines, and most of the production storage tank bottoms in the field were necessarily included in the cathodic protection system. In addition a separate rectifier-graphite anode system with new design features was installed for protection of an emulsion treater and brine h...

Load-dropping tests on a large ignitron rectifier installation

A SERIES of load-dropping tests on ignitron rectifier circuits was conducted during March 1952 on an aluminum potline at the Mead (Wash.) Works of the Kaiser Aluminum and Chemical Corporation. The purpose of these tests was to obtain fundamental data on current and voltage surges encountered in a large ignitron rectifier installation when the potline load was tripped off by each of the following methods.

Electronic regulation of metallic rectifiers

LARGE INSTALLATIONS OF communications equipment, industrial control devices, and computing instruments have given rise to a demand for d-c power supplies having the property of maintaining a constant load voltage. The concentration of such loads in 10-kw units makes it economical to devote development time and first-cost expense to the rectifier installation; and this new dimension in economics has induced considerable development engineering effort in the direction of higher efficiency and more accurate voltage regulation in these power supplies.

Economics of Rectifier Installation For Cathodic Protection of a Bare Pipe Line

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation D. C. GLASS; Economics of Rectifier Installation For Cathodic Protection of a Bare Pipe Line. CORROSION 1 October 1951; 7 (10): 322–326. doi: https://doi.org/10.5006/0010-9312-7.10.322 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest Search

Power Supply Study and New Rectifier Installation for the United Electric Railways of Providence

A study of the power supply to the United Electric Railways was initiated when new construction necessitated the re-location of rotary converters. Replacement with modern equipment was considered in conjunction with a comprehensive study of the entire power supply. It was evident that the losses on the United Electric Railways feeder and trolley system would be the controlling economic factor. A method of calculating the losses in this d-c supply system was developed, correlated with a measured value of losses, and extended to determine the relative merits of proposed feeder changes and rectifier installations. It is believed that this is the first published study that has made use of available probability methods for calculating losses, voltage drop, flicker, and capacity requirements in a study of the power supply for an electric transportation system. The rotary converters were replaced with 60-cycle rectifiers at two new locations. The design of these substations incorporated certain novel features for the protection of equipment and personnel.

Automatic control of ignitron rectifier stations

THE BASIC elements of an ignitron rectifier installation consist of a rectifier, a rectifier transformer, and the necessary switchgear equipment. The rectifier and the rectifier transformer are the same whether the station is automatically or manually controlled.

Automatic Control of Ignitron Rectifier Stations

THE BASIC elements of an ignitron rectifier installation consist of a rectifier, a rectifier transformer, and the necessary switchgear equipment. The rectifier and the rectifier transformer are the same whether the station is automatically or manually controlled.