Compensation Characteristics Research Articles

English

This Paper describes Power Quality Problems in Power system and there solutions with Power electronics based equipements.Several international standard issues to control power quality are briefly described and some important methods to analyses Electrical Circuit with non-sinusoidal waveforms are introduced and evaluated. Passive filters, Shunt, hybrid and series active power filters are described showing their compensation characteristics and principles of operation .Different power circuit’s topologies and control scheme for each type of power filter are analyzed. The compensation characteristics of each topology with respective control scheme are proved by simulation and experimentally. The filter can compensate for harmonic current, power factor and load unbalance. A power filters which has been used there monitors the load current constantly and continuously adapt to the changes in load harmonics.

Bjerknes-like Compensation in the Wintertime North Pacific

AbstractObservational and model evidence has been mounting that mesoscale eddies play an important role in air–sea interaction in the vicinity of western boundary currents and can affect the jet stream storm track. What is less clear is the interplay between oceanic and atmospheric meridional heat transport in the vicinity of western boundary currents. It is first shown that variability in the North Pacific, particularly in the Kuroshio Extension region, simulated by a high-resolution fully coupled version of the Community Earth System Model matches observations with similar mechanisms and phase relationships involved in the variability. The Pacific decadal oscillation (PDO) is correlated with sea surface height anomalies generated in the central Pacific that propagate west preceding Kuroshio Extension variability with a ~3–4-yr lag. It is then shown that there is a near compensation of O(0.1) PW (PW ≡ 1015 W) between wintertime atmospheric and oceanic meridional heat transport on decadal time scales in the North Pacific. This compensation has characteristics of Bjerknes compensation and is tied to the mesoscale eddy activity in the Kuroshio Extension region.

Power Characteristics of the Vibration Isolators

This paper presents the electromagnetic traction characteristics of the vibration isolator rigidity compensator. When defining power, positioning characteristics against each axis should be taken into account. The equation was derived to describe the characteristics of each axis based on rigidity.

The examination of workers’ compensation for occupational fatalities in the construction industry

Construction is one of the most hazardous and risky industries. Construction accidents may result in numerous damages and losses. Workers’ compensation is an important source for estimating the costs of construction accidents. In this article, the applicable laws for occupational injuries and the compensation statistics for construction accidents are examined to identify the characteristics of construction accident compensation in Taiwan. Accident reports during the period 1999–2011 are extracted from case reports of the Northern Region Inspection Office of the Council of Labor Affairs of Taiwan. A total of 574 occupational fatality cases in the construction industry are then analyzed to explore the significant factors for construction accident compensation using analysis of correlation coefficients (Pearson’s r) and analysis of variance (ANOVA).

Design and Application of Motor Start Compensator

This paper illustrates the operating principle and design characteristics of a start compensator for medium-sized asynchronous motor powered by Mobile power cars, and describes its application combined with engineering examples. The start compensator detects the motor phase current in real time by using current transformer to determine the switching time of change-over switch in the start compensator. The start compensator operates in a master-slave control mode and can be used as slave computer to communicate with PC based on MODBUS protocol. Its operation is controlled by means of a PC software interface. The whole control system is characterized by reliable performance and low manufacturing cost .

Study on High Precision Control Scheme of Ceramic Ferrule Concentricity Grinder

The paper analyzes the precision coaxial processing requirements and the characteristics of high automatic online compensation, and builds the electric control system based on Delta series products. The system uses a bus controller and absolute encoders servo constitute nearly closed-loop servo control system, combined with torque limiting grading feeding, dressing real-time compensation, stable and high-speed precision machining ceramic ferrule.

English

In this work a new control strategy for simulation of three phase hybrid power filter for power quality improvement is adapted. This filter consists of shunt passive LC power filter and series active filter, with nonlinear balanced and unbalanced loads and also with variation in the source impedance. A new control method based on dual formulation of instantaneous reactive power vectorial theory is applied by considering a balanced and resistive load as reference load, so that the voltage waveform injected by the active filter is able to attain the objective of achieving reactive power compensation. This also helps in eliminating load current harmonics and also in balancing asymmetrical loads i.e., for achieving ideal behaviour for the set hybrid filter load, Total Harmonic Distortion (THD) is reduced and power factor is improved. This method improves passive filter compensation characteristics without depending on system impedance, avoids the danger of passive filter behaves as harmonic drain of close loads and avoiding series and / or parallel resonance problems. And compensation is also possible with variable loads without detuning the passive filter. And is applied for creating LG/LL faults at the source side. The results show that the active filter improves the compensation characteristics of the passive filter and reactive power is compensated.

Earning differentials by occupational categories: Gender, race and regions

Abstract Analyzing the income differentials amongst the Brazilian workers’ occupations is the focus of this paper. Due to the wide diversity of occupations cataloged by the IBGE (around 800), a theoretical procedure is applied to reduce them to only seven in order to allow statistical treatment of the data. The methodological approach is based on Mincerian quantile equations to be estimated in various strata of the workers’ income distribution, on which a breakdown is made to check the gap among the individuals’ income with distinct inherent attributes and between those living in both more and less developed regions. The estimation results ensure the importance of breakdown analysis for occupational strata as well as for quantiles, since the effects of explanatory variables are distinct along the income distribution and vary among occupations. Regarding the gaps in this distribution, there is a glass ceiling effect in some occupations, that is, the gap is greater at the top of distribution, although in most cases the wider gap occurs at the bottom of the distribution – sticky floor effect, which makes this a distinguished result from other studies. Moreover, contrary to the gap in gender, which is due to the compensation characteristics of individuals only (discrimination), income differentials between regions and races also occur from the heterogeneous characteristics of workers.

Compensation Characteristics of the Distorted WDM Signals Depending on the Variation Degree of RDPS Random Variables in the Optical Links with Dispersion Management and Optical Phase Conjugation

The effects of the variation degree of residual dispersion per span (RDPS) random variables on the compensation characteristics of the distorted signals in optical links with the dispersion management (DM) and the mid-way optical phase conjugator (OPC) are investigated in this paper. In order to obtain this goal, the effective launch power range and the effective net residual dispersion (NRD) range are induced as a function of the variation degree of RDPS random variables. We confirm that it is needed to select the RDPS random variables of the narrow deviation in each fiber spans for implementing the flexible optical links transmitting the relative higher launch power. Also, we confirmed that it is more advantageous to use postcompensation rather than precompensation for expanding the effective NRD range.

MO‐PIS‐Exhibit Hall‐01: Imaging: CT Dose Optimization Technologies I

MO‐PIS‐Exhibit Hall‐01: Imaging: CT Dose Optimization Technologies I

Dynamic Characteristics of Pressure Compensator in Underwater Hydraulic System

A pressure compensator for an underwater hydraulic system is studied in this paper. The compensator is used to maintain the tank pressure of the underwater hydraulic system so that it is slightly greater than the ambient pressure, allowing the system to work at any depth. The dynamic characteristics of the pressure compensator are studied using theoretical analysis, simulation and experiment. The tank pressure changes due to the step flow to the tank coming from the motion of a piston in a single-rod cylinder. This flow is caused by the unequal areas of the piston. The tank pressure change can be mathematically determined. A design procedure focusing on the dynamic characteristics of the pressure compensator is given. A compensator and underwater hydraulic system were built and the dynamic characteristics of the compensator were tested. Both simulation and experimental results conform to the analysis. The study provides a theoretical way to determine the dynamic characteristics of a pressure compensator in an underwater hydraulic system.

Research on the SINS Algorithm Based on Spiral Vector

Targeting at the independent compensation characteristics of cone motion effect and sculling motion effect in traditional SINS Algorithm, this article studies the SINS Algorithm based on spiral vector which enables the cone motion effect and sculling motion effect to compensate at the same time, so as to realize the high precision calculating of attitude Angle and velocity vector. This paper analyzes the mathematical relationships between spiral vector and position-attitude dual quaternion, and then deduces the spiral vector differential equation in detail, which leads to the SINS Algorithm orchestration based on the spiral vector. Finally, considering the real application environment, the actual tests have shown that under the same conditions the spiral vector algorithm of SINS is more precise than the traditional algorithm in high dynamic environment and that the high sub-sample precision is higher than the low sub-sample.

River basin water resource compensation characteristics by set pair analysis: the Dongjiang example

Flood and drought coexist in many river basins, thus analyses of water resource compensation characteristics become important, since they are the foundation for rational utilization of floodwaters. In this research, set pair analysis (SPA), a relatively new uncertainty analysis method, is used to study the dry and wet compensation characteristics of water resource parameters. In addition, fuzzy membership and grey correlation degree are adopted to test the result of set pair analysis. The Dongjiang River is taken as an example and the analyzed parameters include precipitation and mean discharge from different hydrological stations. The results show that there is a high homeotype-encountering chance for precipitation and mean discharge between different stations for both dry and wet conditions; thus the compensation capacity is small. Although the mean discharge is synchronous with the precipitation in the river basin, there exists a certain degree of shift, indicating possible utilization of floodwater on a small scale. The results from SPA are consistent with that from a traditional analysis method, showing that SPA is a promising alternative method for studying river basin water resource compensation characteristics, in particular for exploring potential complements embedded in noncomplementary general features.

Power Quality Enhancement Using Active Power Filters

This paper describes different power quality problems in distribution systems and their solutions with power electronics based equipment. Hybrid, shunt and series active power filters are described showing their compensation characteristics and principles of operation. Dissimilar power circuits topologies and control scheme for every type of active power filter are analyzed. The compensation characteristics of every topology with the individual control techniques are proved by simulation and experimentally.

Do Corporate Board Compensation Characteristics Influence the Financial Performance of Listed Companies?

As the financial performance of entities is of extreme importance to stakeholders in general and shareholders in particular (by helping to maintain a going concern and to increase the value of the business), it should appear as straightforward that identifying and analyzing those factors (determinants) that influence the financial performance is of great relevance both to practice and the academic world. It is logical (however not undisputed) to suppose that the managerial abilities of the board of directors would have a significant impact on the entity's financial performance. It is however not clear-cut whether certain board characteristics regarding its compensation would significantly influence the financial performance of the entity. Within this context, the aim of this research is to investigate (based on econometric regression models) the impact of 5 corporate governance characteristics related to board remuneration on the contemporaneous and next year's performance (measured as ROA/ROE) using a sample of large groups listed on the London Stock Exchange between 2010 and 2011. Through this study we intend to make a contribution to the academic literature on the unsettled issue concerning the relationship between corporate governance and corporate performance. The empirical results proved a significant relationship between non-executive directors’ basic fee, fees paid in shares and additional remuneration for board committee membership (as corporate board compensation characteristics) and both contemporaneous and subsequent financial firm performance.

Harmonic convergence for balanced and unbalanced non-linear load using hybrid filter

A control strategy is suggested for converging harmonics with hybrid filter. The hybrid power filter is constituted by a series active filter and shunt passive filter. The control algorithm works on dual formulation of electric power vectorial theory. Without depending on the system impedance, the active filter improves the compensation characteristic of the shunt passive filter and eliminates the series/shunt resonance problem, the voltage waveform injected by the active series filter is able to compensate for reactive power, eliminates harmonics in load current and balances asymmetrical load.

Frequency Limitation Method for Reducing the Power Rating of a Single-Phase Active Filter

Recently, many energy-saving household appliances such as air conditioners, refrigerators, and LED bulbs are being used in residences. Most household appliances use diode rectifiers equipped with smoothing dc capacitors, which output a large amount of harmonic current into utility lines. This harmonic current may cause electrical equipment to malfunction or fail. This paper discusses the harmonic compensation characteristics and power rating of a single-phase active filter, and proposes the use of control methods for reducing the power rating of the active filter. Furthermore, three single-phase active filters in conjunction with the proposed control method are used in an experiment on a three-phase system. The experimental results confirm that the frequency limitation method is suitable for a single-phase active filter.

Thermal Stress Compensation of MgO Concrete in Construction of High Arch Dams in Cold Areas

When mixed with the admixture MgO, the volume contraction deformation of mass concrete could be compensated, which is an effective way to solve the temperature cracking problems in construction of concrete projects. Taking an arch dam in China as an example, the thermal stress compensation characteristics of MgO concrete in cold areas are studied using the finite element method. Results indicate that the stress compensation of MgO concrete is significant inside the dam, and with a better effect along with a larger mixing amount of MgO in a certain range. But on the surface of the dam, the stress compensation of MgO concrete is not significant.

Design and experimental study of oil-based pressure-compensated underwater hydraulic system

An oil-based pressure-compensated underwater hydraulic system is designed and tested in this article. The underwater hydraulic system is equipped with a pressure compensator so that the tank pressure is always balanced with the ambient pressure. The system pressure is thus built on the ambient pressure. In this way, the underwater hydraulic system can work at any water depth. The steady-state characteristics of a spring-loaded pressure compensator are studied. The pressure compensator, underwater hydraulic power unit and the underwater valve control unit are designed and built. The whole underwater hydraulic system is tested in a high-pressure water simulator with lighting and video system in it. Results show that the underwater hydraulic cylinder can be driven properly under high water pressure, which demonstrates the effectiveness of the pressure compensation in the underwater hydraulic system.

High selectivity filter based reference current generation method for three-level shunt active power filters under adverse source voltage conditions

This paper presents comparison of four different control strategies to generate reference current components for shunt active power filter based on a three-level inverter. These strategies are instantaneous reactive power p–q method, modified p–q method, synchronous d–q reference frame method and I d –I q method. The performance of four methods has been evaluated under different source voltages conditions in steady state. For the same operating conditions, the performance of all control laws are analysed and compared in terms of the total harmonic distortion of source currents. Based on this comparative study, it is possible to select the best strategy to meet the required load compensation characteristics for available source voltages.