Compensation Requirements Research Articles

Optimal PV Allocation & Minimal tap-Changing Transformers Achieving Best Distribution Voltage Profile & Minimum Losses in Active Distribution Networks

In distribution systems, voltage levels of the various buses should be maintained within the permissible limits for satisfactory operation of all electrical installations and equipment. The task of voltage control is closely associated with fluctuating load conditions and corresponding requirements of reactive power compensation. The problem of load bus voltage optimization in distribution systems that have distributed generation (DG) has recently become an issue. In Oman, the distribution code limits the load bus voltage variations within ±6% of the nominal value. Several voltage control methods are employed in active distribution systems with a high share of photovoltaic systems (PV) to keep the voltage levels within the desirable limits. In addition to the constraint of targeting the best voltage profile, another constraint has to be achieved which is the minimum loss in the distribution network. An optimised solution for voltage of load busses with on-load tap-changing (OLTC) tarnsformers and PV sources is presesnted in this paper. This study addresses the problem of optimizing the injected power from PV systems associated with the facilities of tap-changing transformers, as it is an important means of controlling voltage throughout the system. To avoid violating tap-changing constraints, a method is depicted for determining the minimal changes in transformer taps to control voltage levels with distributed PV sources. The taps of a range + 5 to -15 %, can be achieved by tap-changing transformers. The OLTC operation was designed to keep the secondary bus within the voltage standard for MV networks.

The penalty resulting from the breach of the legal expert's obligations under Jordanian law: الجزاء المترتب على إخلال الخبير القضائي بالتزاماته في القانون المدني الأردني

This paper deals with the subject of the penalty resulting from the violation of the obligations of the legal expert in accordance with Jordanian law, it is known that many of the courts of different types and degrees draw in many of the lawsuits the opinion of the people of experience and study on certain issues, or cannot prevent the judge deciding which of its own. Because for his judicial expert of the work is directly related to individuals of society and liberties and rights, which requires him a lot of time and accuracy in achievement, and as the nature of his work related to justice, there must be controls allow opponents of his claim for compensation whenever their right to harm illegal according to the principles Civil responsibility. So the study came to discuss the penalty resulting from the breach of the expert legal obligations for damages that may be caused to opponents and my study was divided through a preliminary study, and two. In the introductory section, it dealt with the civil liability of the judicial expert from the act, damage and causal relationship between the act and the injury. And proving the civil liability of the judicial expert in the first subject. The second part dealt with the effects of the responsibility of the judicial expert in the suits of compensation. This section was divided into two requirements, which dealt with the first requirement of compensation and the judge's discretion, and the second demand on how to compensate the expert's damages.

Hi-C guided assemblies reveal conserved regulatory topologies on X and autosomes despite extensive genome shuffling.

Genome rearrangements that occur during evolution impose major challenges on regulatory mechanisms that rely on three-dimensional genome architecture. Here, we developed a scaffolding algorithm and generated chromosome-length assemblies from Hi-C data for studying genome topology in three distantly related Drosophila species. We observe extensive genome shuffling between these species with one synteny breakpoint after approximately every six genes. A/B compartments, a set of large gene-dense topologically associating domains (TADs), and spatial contacts between high-affinity sites (HAS) located on the X chromosome are maintained over 40 million years, indicating architectural conservation at various hierarchies. Evolutionary conserved genes cluster in the vicinity of HAS, while HAS locations appear evolutionarily flexible, thus uncoupling functional requirement of dosage compensation from individual positions on the linear X chromosome. Therefore, 3D architecture is preserved even in scenarios of thousands of rearrangements highlighting its relevance for essential processes such as dosage compensation of the X chromosome.

Individuals’ economic value orientation or social equity value orientation? A dual value orientation in the process of house demolition compensation

The development of society and the economy has given rise to housing demolition. Using the psychological perspective of reference points, this paper studied the effects of tri-reference points (TRP) and social comparison on demolition compensation fairness perception through experiments in a demolished community. According to TRP theory, there are three special reference points (minimum requirements, status quo, and goal) when people make decisions. Our research finds that there exists a dual value orientation in the demolition compensation process: before the compensation amount reaches the status quo, the individual’s economic value orientation dominates; after achieving the status quo, a social equity value orientation dominates. In addition, the research results also show that demolished households pay the most attention to the minimum requirements of compensation; the fairness perception is very low below the minimum requirements, even when the compensation amount is the same or higher than that of others. Therefore, in the future implementation of compensation for demolition, the minimum requirements should be taken as the first priority. It is not necessary to arbitrarily increase the amount of compensation; it is better to set it between the status quo and the goal. Finally, ensuring that the demolished households are treated equally is very important.

Direct bonding of LiNbO3 and SiC wafers at room temperature

Application of the surface activated bonding (SAB) method to direct bonding of LiNbO3 and SiC was investigated. SAB using argon fast atom beam bombardment resulted in the successful formation of a room-temperature bonded LiNbO3/SiC wafer for the first time. Cross-sectional transmission electron microscopy (TEM) observations showed a void-free bonded interface at the atomic level. The bonded interface had an amorphous-like layer that was a few nanometers thick, which was considered to be formed during the bombardment process. The resulting LiNbO3/SiC structure can be utilized to realize a new configuration of various devices including surface acoustic wave filters for use in high-power applications that can satisfy both temperature compensation and heat dissipation requirements.

Adaptive Anti-Swing and Positioning Control for 4-DOF Rotary Cranes Subject to Uncertain/Unknown Parameters With Hardware Experiments

Among various large-scale mechanical equipments, a rotary crane is one of the most practical hoisting machineries utilized in factories and docks. However, the inaccurate measurement of friction coefficients and the requirement of accurate gravity-related compensation may inevitably increase the difficulty for controlling such systems. For most existing control methods, the exact model knowledge is required; otherwise, positioning errors would unavoidably appear, which brings many limitations for their practical applications. To deal with these problems, in this paper, a novel adaptive control approach is suggested, in which a novel update law is designed to achieve accurate identifications of unknown parameters as well as exact compensation of the gravity-related lumped term. Moreover, the payload can be transported to its specified location precisely via the boom’s rotation with effective payload swing suppression. Specifically, without linearizing the nonlinear dynamic model of the rotary crane system, the state variables are ensured to be asymptotically convergent to the equilibrium point, which is proven strictly in theory by utilizing Lyapunov techniques and LaSalle’s invariance principle. Finally, experimental results indicate the effectiveness and practicability of the proposed approach.

Voltage waveform tailoring in radio frequency plasmas for surface charge neutralization inside etch trenches

The etching of sub micrometer high-aspect-ratio (HAR) features into dielectric materials in low pressure radio frequency technological plasmas is limited by the accumulation of positive surface charges inside etch trenches. These are, at least partially, caused by highly energetic positive ions that are accelerated by the sheath electric field to high velocities perpendicular to the wafer. In contrast to these anisotropic ions, thermal electrons typically reach the electrode only during the sheath collapse and cannot penetrate deeply into HAR features to compensate the positive surface charges. This problem causes significant reductions of the etch rate and leads to deformations of the features due to ion deflection, i.e. the aspect ratio is limited. Here, we demonstrate that voltage waveform tailoring can be used to generate electric field reversals adjacent to the wafer during sheath collapse to accelerate electrons towards the electrode to allow them to penetrate deeply into HAR etch features to compensate positive surface charges and to overcome this process limitation. Based on 1D3V particle-in-cell/Monte Carlo collision simulations of a capacitively coupled plasma operated in argon at 1 Pa, we study the effects of changing the shape, peak-to-peak voltage, and harmonics’ frequencies of the driving voltage waveform on this electric field reversal as well as on the electron velocity and angular distribution function at the wafer. We find that the angle of incidence of electrons relative to the surface normal at the wafer can be strongly reduced and the electron velocity perpendicular to the wafer can be significantly increased by choosing the driving voltage waveform in a way that ensures a fast and short sheath collapse. This is caused by the requirement of flux compensation of electrons and ions at the electrode on time average in the presence of a short and steep sheath collapse.

Power quality improvement of distribution system with photovoltaic and permanent magnet synchronous generator based renewable energy farm using static synchronous compensator

This paper presents power quality improvement for effective power transfer in a grid-integrated solar photovoltaic-wind energy hybrid system. The hybrid system constitutes a renewable energy farm, based on photovoltaic energy generation system and wind energy conversion system. The system experiences frequent disturbances in AC loads and power output from the renewable farm. This creates reactive power mismatch and raises voltage instability and power quality issues. This gap can be eliminated using an adjustable reactive power source i.e. static synchronous compensator. Three case scenarios of the hybrid system, i.e. hybrid system in (I) standalone mode, (II) grid-integrated mode and (III) grid-integrated mode with STATCOM, are tested to compare their dynamic and transient performances. Results show that scenario-III best fulfilled the dynamic compensation requirement among all cases. Under this scenario, load bus voltage is regulated at around 1.0 p.u. and total harmonic distortion in voltages/currents are maintained at around 1%. Furthermore, this scenario demonstrated superior transient response towards a step change in reactive power load, significantly reducing maximum peak deviation by 73.4% and settling time by 75% in load voltage compared to the worst case of scenario-I.

Graphoanalytic determination of symmetry parameters and total compensation of reactive power for a three-phase power supply system

Problem. The simulation of currents and voltages in electric three-phase power supply systems is an important means of improving the quality of electrical supply. It is precisely the alignment of the values of currents in the phases of electricity supply lines, thus, the power supplies are loaded evenly. In addition to the symmetry to reduce losses in the transmission of electrical energy, it is necessary to provide transmission from the source to the loading of only active power. Therefore, it is necessary to determine the parameters of symmetric-compensating devices, which, given the fact that active-reactive line resistance is taken into account, is a rather complicated task. Numerical optimization algorithms are used to solve this problem, the disadvantage of which is the possibility of not receiving a solution due to unsuccessful selection of initial approximation of parameters and (or) excessive number of computational operations. To solve such problems, symmetro-compensating devices are used. The need to take into account the influence of active-reactive resistance of transmission lines with accurate calculation of the parameters of symmetro-compensating devices requires the use of computer models and numerical optimization methods and subroutines. Goal. Development of the method of determining the parameters of the symmetrical device for three-phase power supply systems, based on the analysis of the existing operating mode of the system with subsequent graph-analytical determination of the parameters of the symmetry and full compensation of reactive power. Methodology. The complex methods of analysis of linear electric circuits are used. To determine the requirements of symmetry and compensation, the method of symmetric components is used. To determine the parameters of the compensating device, methods of analytic geometry are used, as well as matrix methods for solving systems of linear algebraic equations. Results. The proposed method allows graphoanalytic way to obtain a numerical solution to the problem of symmetry of currents in the line and compensation of reactive power in a three-phase power supply system with asymmetric load. It has been established that the parameters of the symmetric device, determined from the data of the initial analysis of the mode of operation of the power supply system with an asymmetric load, do not always provide a sufficient effect of symmetry and compensation. To improve the efficiency of the symmetry and compensation parameters of the simulating device should be specified according to the primary compensation. Originality. It is proposed to make an initial assessment of the mode of operation of the power supply system. Based on the initial assessment, the primary requirements for the parameters of symmetry and compensation are determined. Approximate values of the parameters of the symmetry and compensation are determined by processing the initial requirements by methods of analytical geometry. The effect of primary symmetry and primary compensation was estimated, and the primary requirements were clarified. After the correction, the full effect of the symmetry of currents and the compensation of reactive power in the lines of the power supply system have been achieved. Practical value. The proposed method allows to calculate the parameters of the symmetric compensation devices with high accuracy taking into account the resistance of lines in power supply systems with a wide range of changes in asymmetry and reactivity of loads, which ensures reduction of losses due to excessive asymmetry and reactivity of consumers.Key words: three-phase system; asymmetry; symmetrical device; reactive power compensation.

NIMBY, not, in siting community wind farms

Public opinion polls show that many Americans support wind energy development while wind-farm projects often face local opposition. This dichotomy between general support for wind energy and local opposition is often attributed to the not-in-my-backyard (NIMBY) phenomenon. In this study, we employ a discrete-choice experiment to investigate public preferences for different characteristics of a local wind farm. We investigate NIMBY by first controlling for characteristics that might cause local opposition, such as seeing or hearing a wind farm from home. We find people who favor wind energy do not display NIMBY, they favor wind energy and wind-farm development. We estimate compensation requirements for siting a wind farm within sight or sound of someone’s home; most people (79%) who are favorable toward wind energy (85% of respondents) would support the wind farm without compensation. Their concerns could be addressed through compensation payments or adjusting wind-farm placement and design considerations. Those who oppose wind energy (7% of respondents) may continue to oppose a wind-farm even in the face of compensation payments. Overall, our results do not support that NIMBY exists and applying this label to those who favor wind energy is not helpful to affirmative discussions to facilitate wind-farm permitting and development.

Power Quality Improvement and PV Power Injection by DSTATCOM With Variable DC Link Voltage Control from RSC-MLC

The study proposes a method to optimize dc-link voltage of distribution static compensator based on load compensation requirement using reduced switch count multilevel converter (RSC-MLC) integrated with photovoltaic (PV) system. The proposed method is capable of compensating reactive power, unbalance, and harmonics demanded by three-phase unbalanced and nonlinear loads connected to the distribution side, leading to improvement of power quality. It is also capable of providing real power support to the load and thus prevents source from getting over loaded whenever required. During off-peak loads, the dc-link voltage can be brought down to a lower value, which will reduce the voltage-stress across switches of inverter and minimizes the switching losses. The variation of dc-link voltage is provided using RSC-MLC, which requires dc voltage supply. This method utilizes renewable resources of energy such as solar cells as the dc voltage source. The output voltage of PV panel is boosted to a higher value using high gain boost converter and given to RSC-MLC. The maximum power point tracking of PV panels is achieved by using Perturb and Observe algorithm. The results have been verified through simulation and experimental studies.

Direct Control Strategy of Real-Time Tracking Power Generation Plan for Wind Power and Battery Energy Storage Combined System

To improve the overall economy of the wind-energy storage power station, a direct control strategy is proposed to track the deviation of the wind power plan. Compared with the traditional strategy of wind power fluctuation mitigation, the control strategy in this paper can change the charge and discharge power of energy storage in real-time according to the deviation of wind power and the state of charge (SOC). When the power of wind power changes suddenly, the strategy can make the valid judgment and prevent control failure, so that Grid-connected power of wind farm in extreme cases can also meet the requirements of the safe and stable operation of the power system. The strategy uses the discrete Fourier transform (DFT) to analyze the power deviation of the wind farm in the frequency domain and obtains power compensation requirements for different time scales. Energy storage equipment with corresponding characteristics is used to classify control of deviation of wind power. The compensated power deviation can meet the requirements in market competition. At the same time, the power exchange between storage systems is carried out to optimize the state of charge in real-time and make the energy-type energy storage in shallow charge/discharge state, which effectively reduces the repeated regulation of energy storage systems. Finally, this paper establishes a comprehensive economic benefit model of the energy storage system. Combining the Markov Chain Monte Carlo method (MCMC) and backward scenario reduction technology generate multiple scenarios. The calculation results show that the proposed strategy can effectively track the deviation of the wind power plan. Furthermore, prolong the service life of the energy storage system and improve the market competitiveness of wind power.

Dual-Band Infrared Radiation for Rotating Missile Attitude Measurement and Interference Compensation

With the continuous development of infrared technology and its extensive usage in the military, the infrared radiation attitude measurement technology is attracting more and more attention. Aiming at the compensation requirement for complex infrared background interference during the rotating missile infrared attitude measurement, the theoretical research on the dual-band infrared rotating missile attitude measurement is carried out. The mechanism and interference characteristics of the earth infrared radiation are analyzed according to the flying missile movement characteristics. The atmosphere propagation in 3~5-μm and 8~14-μm infrared radiation bands are studied, and the dual-band infrared radiation attitude measurement model is established. Then, the influence of cloud infrared radiation interference on the dual-band infrared radiation sensor is analyzed, and a nighttime dual-band infrared radiation attitude measurement difference compensation algorithm is proposed to obtain the compensated attitude angle parameter. The results of the semi-physical experiments show that the compensated roll angle error is within ±0.6° and the pitch angle error is within ±1°. The dual-band infrared radiation attitude measurement difference compensation algorithm can effectively eliminate the effects of cloud infrared radiation interference and improve the anti-interference ability of infrared radiation attitude measurement.

Selection of desirable transmission power mode for the bundled wind-thermal generation systems

Although the integration of large–scale clean wind power will have a positive impact on the environment deterioration and reduce the fossil fuel depletion, it also creates challenges for power system operations. Considering that some countries, such as China, hold a geographical advantage of adjacent distributions of wind and coal resources, i.e., the windy areas are located/close to the areas with vast coal reserves, one feasible plan of both utilizing the large–scale wind power and alleviating the operation burden of power systems is to build bundled wind–thermal generation systems (BWTGSs). This paper first gives the optimal BWTGSs (investment) planning method, in which the cost changing rules, the candidate scheme formation, and long–term wind–thermal coordinated generation scheduling simulation are introduced. Then based on different compensation purposes or requirements, four transmission power modes, i.e., constant transmission power mode, thermal–generation–smoothed transmission power mode, transmission power mode considering load pattern of receiving system, and sectioned transmission power mode, are proposed. Finally, numerical studies are conducted. Planning results show that the generator schemes, total costs, and clean energy proportions differ when adopting different transmission modes, and the sectioned transmission power mode is the most desirable mode with the lowest total planning cost and the highest clean energy proportion.

ISAR Autofocus Imaging Algorithm for Maneuvering Targets Based on Phase Retrieval and Gabor Wavelet Transform

The imaging issue of a rotating maneuvering target with a large angle and a high translational speed has been a challenging problem in the area of inverse synthetic aperture radar (ISAR) autofocus imaging, in particular when the target has both radial and angular accelerations. In this paper, on the basis of the phase retrieval algorithm and the Gabor wavelet transform (GWT), we propose a new method for phase error correction. The approach first performs the range compression on ISAR raw data to obtain range profiles, and then carries out the GWT transform as the time-frequency analysis tool for the rotational motion compensation (RMC) requirement. The time-varying terms, caused by rotational motion in the Doppler frequency shift, are able to be eliminated at the selected time frame. Furthermore, the processed backscattered signal is transformed to the one in the frequency domain while applying the phase retrieval to run the translational motion compensation (TMC). Phase retrieval plays an important role in range tracking, because the ISAR echo module is not affected by both radial velocity and the acceleration of the target. Finally, after the removal of both the rotational and translational motion errors, the time-invariant Doppler shift is generated, and radar returned signals from the same scatterer are always kept in the same range cell. Therefore, the unwanted motion effects can be removed by applying this approach to have an autofocused ISAR image of the maneuvering target. Furthermore, the method does not need to estimate any motion parameters of the maneuvering target, which has proven to be very effective for an ideal range–Doppler processing. Experimental and simulation results verify the feasibility of this approach.

Modular Embedded Multilevel Converter for MV/HVDC Applications

Many of the renewable energy resources, like offshore wind, utility PV farms, are located far away from the load centers, which requires dc power transmission system to efficiently deliver power. Voltage-source converter solution is required in many applications due to the stability and compensation requirement. This paper presents a new voltage source converter topology for medium to high voltage dc application, named modular embedded multilevel converter (MEMC). MEMC is based on a three-level topology structure and consists of series-connected insulated-gate bipolar transistor (IGBT) bridge stacks, like the popular modular multilevel converter (MMC) and series-connected thyristor or press-pack high voltage integrated gate-commutated thyristor or IGBT stacks. The basic operation principle, control solutions, and the methods to commutate the thyristors are explained in detail. Due to the three-level structure, the total number of IGBT stacks are reduced by half compared with MMC, leading to much lower energy storage, weight, volume, and system complexity. Also by replacing part of the IGBT stack in MMC with thyristor stack, both of the system conduction loss and switching loss can be further reduced. There are other topology variations of MEMC with a similar operational principle but different characteristics.

A simple and rapid calibration methodology for industrial robot based on geometric constraint and two-step error

PurposeThe purpose of this study is the presentation and research of a simple and rapid calibration methodology for industrial robot. Extensive research efforts were devoted to meet the requirements of online compensation, closed-loop feedback control and high-precision machining during the flexible machining process of robot for large-scale cabin.Design/methodology/approachA simple and rapid method to design and construct the transformation relation between the base coordinate system of robot and the measurement coordinate system was proposed based on geometric constraint. By establishing the Denavit–Hartenberg model for robot calibration, a method of two-step error for kinematic parameters calibration was put forward, which aided in achievement of step-by-step calibration of angle and distance errors. Furthermore, KUKA robot was considered as the research object, and related experiments were performed based on laser tracker.FindingsThe experimental results demonstrated that the accuracy of the coordinate transformation could reach 0.128 mm, which meets the transformation requirements. Compared to other methods used in this study, the calibration method of two-step error could significantly improve the positioning accuracy of robot up to 0.271 mm.Originality/valueThe methodology based on geometric constraint and two-step error is simple and can rapidly calibrate the kinematic parameters of robot. It also leads to the improvement in the positioning accuracy of robot.

Trajectory and velocity planning of the robot for sphere-pipe intersection hole cutting with single-Y welding groove

The influence of welding preparation and surface treatment of the weldment on welding quality is very important. Single Y-groove technique is a common surface treatment technique in intersecting curve welding. This paper presents a trajectory and velocity planning method for robot to machine a spherical single Y-groove. First, the geometrical models of the sphere-pipe intersection and the single Y-groove are established. This model can cover most of the intersection modes and parameterizes the groove angle and root face height to obtain the optimum process parameters. The above model forms the basis of robot trajectory planning and is the core innovations of this paper. Based on this model and the principle of three-dimensional tool compensation, our paper designs the interface of cutting robot tool compensation. Through this interface, the operators can flexibly change the radius to adapt to different tools or cutting torches, which can fulfill the requirements of dynamic compensation. As the goal of our paper, this method gives a general trajectory description of the robot and introduces two algorithms for the velocity planning to ensure the stability of the robot velocity. Finally, this paper takes the plasma cutting as example, and gives the relevant algorithm to solve the optimal start position and orientation of the plasma torch, which can avoid the cutting defects.

The selection of temperature-sensitivity points based on K-harmonic means clustering and thermal positioning error modeling of machine tools

In the thermal error compensation technology of CNC machine tools, the core is to establish a mathematical model of thermal error with high predictive accuracy and strong robustness. The prerequisite for the error model is to select the optimum temperature-sensitivity points, which can inhibit the multi-collinearity problem among temperature points and improve the predictive accuracy and robustness of the error model. In this paper, K-harmonic means (KHM) clustering is introduced for the first time to select the temperature-sensitivity points in the field of error modeling. In statistical numerical experiments, it is verified that KHM clustering is very stable and requires relatively small number of iterations to converge comparing with the common clustering methods such as K-means (KM) clustering and fuzzy C-means clustering (FCM). Then, the effect of KHM clustering on the selection of temperature-sensitivity points is validated in the actual experiments. Multiple linear regression model combined with KHM clustering (MLR-KHM) is adopted to construct the thermal error model of positioning error. The experimental results demonstrate that the predictive accuracy and robustness of MLR-KHM error model can conform with the requirements of the error compensation.

Zn Incorporation in X and Z-Type Hexagonal Ferrites Ba(Zn,Fe)15O23 and Ba3(Zn,Fe)26O41

Interatomic distance considerations and site occupancy refinements indicate that Zn2+ is exclusively located on tetrahedral sites in both Z and X-type hexagonal ferrites. Zinc is more strongly enriched in four layer thick spinel blocks of X-type hexaferrite than in the two layer thick spinel blocks of both magnetic oxides. No zinc was incorporated in the tetrahedra of the T blocks of Z-type hexaferrite. Bond valence analyses reveal different local charge compensation requirements as origin of the unequal distribution of diamagnetic Zn2+ over the tetrahedral sites, which strongly modify the magnetic properties. Diamagnetic zinc is more strongly enriched on the tetrahedral sites in the four layer thick spinel blocks of X-type hexaferrite than in the two layer thick spinel blocks of both compounds which strongly modifies their magnetic properties.