Transformer Losses Research Articles

Analysis of loss on single-phase dry transformers with non-linear load

The paper studies power losses in transformers due to non-linear loads. The research aims to analyze the power loss in a single-phase dry transformer under a non-linear load. The research uses an SW43W Power supply type, FlukeView Power Quality Analyzer as a DC or AC power supply on the primary side of the transformer. The non-linear load is connected to the secondary side. The loading test of the dry transformer was carried out at non-linear loads. The load variations used 0 %; 12.5 %; 25 %; 37.5 %; 50 %; 62.5 %; 75 %; 87.5 % and 100 %, as well as variations in the THD value by adjusting the ignition angle (α). The non-linear loads used are Half-Wave Rectifier and Controlled Half-Wave Rectifier with resistive loads with variations in THD values. The results showed that the transformer losses comprised Pno load and Pload. The operation of the transformer with constant input voltage and frequency with THDv<5 % resulted in a constant Pno load value at all load values. The greater the percentage of the load, the higher the load. The increase in THD because of non-linear load will increase the load on the transformer. The value of the derating factor is obtained by connecting the increase in losses (∆PLosses), which is influenced by THD and the increase in temperature T(°C) in dry transformers. When the transformer is loaded with a non-linear load, the derating factor<1. THD and derating factor form a linear relationship, when THD increases, the derating factor value decreases. Linear load on the transformer causes a decrease in its capacity, but if it gets a non-linear load with THD=39.1 %, it can withstand a load of 84.294 %, besides the increase in total harmonic distortion will increase losses and reduce transformer capacity

Long-term organic substitution management affects soil phosphorus speciation and reduces leaching in greenhouse vegetable production

Excessive phosphorus (P) fertilizer and manure application is widespread in greenhouse vegetable production, causing P accumulation and groundwater pollution. The partial substitution of chemical fertilizer with organic amendments may effectively address this problem; however, little is known about P speciation and transformation at the molecular scale. Here, we combined P K-edge X-ray absorption near-edge structure, 31P nuclear magnetic resonance spectroscopy, and chemical extraction to characterize P speciation and assess P leaching in a 10-year field experiment including chemical fertilizer (4CN) and replacement of half the chemical N fertilizer with manure (2CN+2 MN), straw (2CN+2SN), or combined manure and straw (2CN+1 MN+1SN) treatments. Compared to the 4CN treatment, organic substitution treatments resulted in 10.0–16.3% lower P accumulation and 57.3–102% higher organic P. Newberyite was detected in the organic substitution treatments, making up 6.9–13.0% of the total P, and the hydroxyapatite proportion was 7.3–15.6% lower than that in the 4CN treatment. Moreover, 2CN+2 MN treatment increased the orthophosphate diester content and labile P (Resin-P and NaHCO3–P) proportion, and 2CN+2SN treatment increased the orthophosphate monoester content and moderately labile P (NaOH–P) proportion. The 2CN+1 MN+1SN treatment exhibited the advantages of both manure and straw application. Partial least squares path modeling revealed that labile P was affected mainly by manure application and pH, and moderately labile P was influenced mainly by straw application and alkaline phosphomonoesterase activity. Compared with the 4CN treatment, the organic substitution treatments significantly decreased the total P leaching losses by 21.3–48.8%. Our results provide new insights into soil P transformation in response to different organic amendments. Combined manure, straw, and chemical fertilizer application (2CN+1 MN+1SN treatment) was a more effective practice for developing sustainable P management practices by comprehensively considering soil P transformation, vegetable yields, and environmental losses.

Passive Reactive Power Compensators for Improving the Sustainability of Three-Phase, Four-Wire Sinusoidal Systems Supplied by Unbalanced Voltages

Compensation of reactive power is necessary in power systems due to economical, energetic, and environmental reasons. Reactive power increases energy power losses and carbon dioxide emissions in distribution lines and power transformers. However, capacitor banks used in most industrial applications do not significantly reduce energy losses in lines and transformers when supply voltages and loads are unbalanced and therefore do not fully improve the sustainability of distribution networks. This fact is explained in this paper using positive-, negative-, and zero-sequence reactive power components in three-phase, four-wire sinusoidal power systems supplied with unbalanced voltages. Likewise, several devices have also been developed for the compensation of the total reactive power and, specifically, for each of its components in these power systems. Comparing the effectiveness of these reactive compensators and other well-known passive compensators as capacitor banks on the sustainability improvement of the electrical installation of an actual industry, reductions between 20% and 100% in energy losses and carbon dioxide emissions, caused by circulation of reactive currents in transformer and lines, can be expected depending on the type of compensator used.

Comparison of Isotonic Activation of Cell Volume Regulation in Rat Peritoneal Mesothelial Cells and in Kidney Outer Medullary Collecting Duct Principal Cells.

In disease states, mesothelial cells are exposed to variable osmotic conditions, with high osmotic stress exerted by peritoneal dialysis (PD) fluids. They contain unphysiologically high concentrations of glucose and result in major peritoneal membrane transformation and PD function loss. The effects of isotonic entry of urea and myo-inositol in hypertonic (380 mOsm/kg) medium on the cell volume of primary cultures of rat peritoneal mesothelial cells and rat kidney outer medullary collecting duct (OMCD) principal cells were studied. In hypertonic medium, rat peritoneal mesothelial cells activated a different mechanism of cell volume regulation in the presence of isotonic urea (100 mM) in comparison to rat kidney OMCD principal cells. In kidney OMCD cells inflow of urea into the shrunken cell results in restoration of cell volume. In the shrunken peritoneal mesothelial cells, isotonic urea inflow caused a small volume increase and activated regulatory volume decrease (RVD). Isotonic myo-inositol activated RVD in hypertonic medium in both cell types. Isotonic application of both osmolytes caused a sharp increase of intracellular calcium both in peritoneal mesothelial cells and in kidney OMCD principal cells. In conclusion, peritoneal mesothelial cells exhibit RVD mechanisms when challenged with myo-inositol and urea under hyperosmolar isotonic switch from mannitol through involvement of calcium-dependent control. Myo-inositol effects were identical with the ones in OMCD principal cells whereas urea effects in OMCD principal cells led to no RVD induction.

Sliced Wasserstein based Canonical Correlation Analysis for Cross-Domain Recommendation

• A cross-domain recommendation model based on Sliced Wasserstein autoencoder is proposed. • An improved cross-domain transformation loss of orthogonal transformation is proposed. • Rigorous experiments were carried out to demonstrate the efficiency of the model. To solve the problem of data sparsity and cold start, the cross-domain recommendation is a promising research direction in the recommender system . The goal of cross-domain recommendation is to transfer learned knowledge from the source domain to the target domain by different means to improve the performance of the recommendation. But most approaches face the distribution misalignment . In this paper, we propose a joint learning cross-domain recommendation model that can extract domain-specific and common features simultaneously, and only use the implicit feedback data of users without additional auxiliary information. To the best of our knowledge, it is the first attempt to combine the sliced Wasserstein distance and canonical correlation analysis for the cross-domain recommendation scenario. Our one intuition is to reduce the reconstruction error caused by the variational inference based autoencoder model by the optimal transportation theory. Another attempt is to improve the correlation between domains by combining the idea of the canonical correlation analysis. With rigorous experiments, we empirically demonstrated that our model can achieve better performance compared with the state-of-the-art methods.

Analysis of Technical Loss Calculation Using Load Curve Approach on 20 kV Distribution Network

Energy loss (losses) is the loss of a certain amount of energy generated when it is distributed to consumers so that it affects the profitability of the company concerned. The size of the losses from an electric power system shows the level of efficiency of the system, the lower the percentage of losses that occur the more efficient the system. Energy losses in the distribution network are generally divided into two, namely technical and non-technical losses. The calculation of technical losses in the 20 KV medium distribution network of PT PLN (Persero) Ulp Matang Glumpang Dua is carried out using the load curve approach method and using the help of the Microsoft Exel program, while the technical losses calculated are technical losses on the Medium Voltage Network and Distribution Transformer. From the results of the analysis of the calculation of technical losses in 2020, the total technical loss value at MG-01 Matang City is in the range of 13.8% to 20.8% which consists of the average technical loss in the Medium Voltage Network feeder of 0.02%. and the loss of Distribution Transformer by 17.6%.

Hybrid Power Electronic Transformer Model for System-Level Benefits Quantification in Energy Distribution Systems

The Hybrid Power Electronic Transformer (HPET) has been proposed as an efficient and economical solution to some of the problems caused by Distributed Energy Resources and new types of loads in existing AC distribution systems. Despite this, the HPET has some limitations on the control it can exert due to its fractionally-rated Power Electronic Converter. Various HPET topologies with different capabilities have been proposed, being necessary to investigate the system benefits that they might provide in possible future scenarios. Adequate HPET models are needed in order to conduct such system-level studies, which are still not covered in the current literature. Consequently, this article presents a methodology to develop power flow models of HPET that facilitate the quantification of controllability requirements for voltage, active power and reactive power. A particular HPET topology composed of a three-phase three-winding Low-Frequency Transformer coupled with a Back-to-Back converter is modeled as an example. The losses in the Back-to-Back converter are represented through efficiency curves that are assigned individually to the two modules. The model performance is illustrated through various power flow simulations that independently quantify voltage regulation and reactive power compensation capabilities for different power ratings of the Power Electronic Converter. In addition, a set of daily simulations were conducted with the HPET supplying a real distribution network modeled in OpenDSS. The results show the HPET losses to be around 1.3 times higher than the conventional transformer losses over the course of the day. The proposed methodology offers enough flexibility to investigate different HPET features, such as power ratings of the Power Electronic Converter, losses, and various strategies for the controlled variables. The contribution of this work is to provide a useful tool that can not only assess and quantify some of the system-level benefits that the HPET can provide, but also allow a network-tailored design of HPETs. The presented model along with the simulation platform were made publicly available.

Thermal Analysis and Energy Efficiency Improvements in Tunnel Kiln for Sustainable Environment

Kiln is a prime need in the ceramics industry, where energy loss is a major part which consumes about 60% production cost through thermal energy for different applications. Higher density of fired and tunnel kiln refractory material lowers the thermal diffusivity and the proper selection of fired material minimizes the energy loss along the kiln. In particular, this research analysed the results of a heat recovery system comprised of a metallic recuperator which gives around 8% energy savings in natural gas consumption. In this work, detailed power quality analysis of low-power factor motors of a tunnel kiln was carried out and a power factor improvement solution was suggested to save electrical energy with payback period of 0.8 y. The motor operating at a low-power factor consumes more reactive power which does not produce beneficial work. A low-power factor around 0.4 causes network power loss, increases in transformer loss and voltage drops. The solution with accumulative capacitance power of 148.05 uF was installed to achieve the power factor to 0.9. Flu gas analyzer was installed to monitor the range of O2 in pre-heating, oxidation, and firing zones of the kiln which should be ≥8% and 3%, respectively. Regression analysis for thermal energy consumption of a tunnel kiln is done to find the forecast thermal energy consumption. This analysis can be used to find operational efficiency, supporting decisions regarding dependent variable of thermal energy consumption and independent variable of production. This research is very helpful for the ceramics industry to mitigate the energy loss at SMEs as well as in mass production level.

Design and Analysis of Planar Transformers in Modern Switching Mode Power Supply

This paper presents a development and calculated rating of high-frequency transformer connect with switch-mode power supplies. These power supplies are used in various devices such as power personal communications services, television, DVD players and charge mobile phones Thus, increasing power density and decreasing cost are still the main factors in designing a switch-mode power supply. Magnetic elements represent a great amount of size in switch-mode power supplies and therefore volume reduction and power density raise are beneficial. These switch-mode power supplies consist of two power stages separated by a power transformer with high frequency power. The transformer architecture, which can run at a high frequency, has since become a major challenge for the engineers. Lower component height and better thermal management are advantages with the planar core design. This paper provides a detailed summary of the operating principles of high-frequency transformers. Two transformers are compared in a dual active bridge converter: a wire wound, a planar. This paper discusses a comparison between the wire-wound transformer, high-frequency transformer, and structures in terms of winding loss, core loss, leakage inductance, parasitic capacitance the focus of this research is to find an optimal transform solution for the converter operating at a power level of 220 W. Furthermore, the power losses of a planar transformer are estimated.

A Retargetable Model-Driven Framework for the Development of Mobile User Interfaces

Since the emergence of mobile devices, the architecture of mobile applications has been transformed significantly. In mobile applications, the User Interface (UI) is one of the major elements, but its development is complex and time-consuming. Existing practices do not support various presentation issues of the UI at a higher abstraction level, in a retargetable fashion, with complete tool support. Therefore, it is critical to develop a simple and automated framework for the development of mobile UIs by exploiting model-driven engineering concepts. In this paper, a Unified Modeling language (UML) profile for Mobile User Interfaces (UMMUI) has been proposed, which employs some standard UML notations for representing the mobile UI requirements at a higher abstraction level. Subsequently, a complete open-source transformation engine has been developed to automatically transform the high-level source models (in UMMUI) into the target low-level React Native implementation. Finally, the applicability of the proposed framework is validated through two benchmark case studies, i.e., Patient Management System and Library Application. The results verify that the proposed framework allows the modeling of UIs with simplicity and generates the target code automatically with minimum transformation losses.

Design and planning of a distribution system using renewable technologies in a rural area of Pakistan

The inclusion of renewable energy sources in a distribution system to form a dispersed or decentralized generation network has gained tremendous progress in recent years. The architecture of the distribution system has the potential to serve as a microgrid during an islanding operation connected directly to the load center while excited fully by renewable technologies. This paper deals with planning and designing of a medium voltage power distribution system in a rural area of Pakistan affluent with abundant reserves of renewable sources of electricity. Two types of distribution system architectures, namely radial and ring systems, are simulated using a power flow algorithm with three types of renewable generation technologies: solar, wind, and biogas. The theoretical study involves realistic parameters such as total houses, estimated load, distance of the load from proposed generation site, solar irradiance, wind speed, and biogas reserves. As a result, transformer losses, line losses, power factor, and voltage profile across the load are evaluated for both system types and compared. It is concluded that the ring system maintains better voltage profile, higher power factor, and less transformer and line losses as compared to the radial system. All the relevant construction details together with the electrical and operational parameters of the power system need to be processed accurately in a computer program. Such a program has been modeled as part of this research with embedded methods and conditions outlined in this paper.

The influence of the deforming regime on the losses of power and energy in the electrical transformers on board the cruise ships

Power transformers are the basic components of a naval power system at the same time as the equipment with the most significant losses. The deforming regime is introduced by the power electronics in the case of ships of static frequency converters, cycloconverters or syncroconverters (variable speed drives) for the control of propulsion motors, etc. The central theme of this paper is the impact of the deforming regime on power and energy losses in the case of electrical transformers on board cruise ships. For this purpose, the analytical model regarding the determination of losses in transformers when operating in deforming regime is presented. In addition to the winding losses, the magnetic and dielectric circuit also includes additional losses due to the deforming regime. At the same time, an analysis was performed regarding the optimal operation management of the power transformers affected by the deforming regime.

Decoupling the Role of Data, Attention, and Losses in Multimodal Transformers

AbstractRecently, multimodal transformer models have gained popularity because their performance on downstream tasks suggests they learn rich visual-linguistic representations. Focusing on zero-shot image retrieval tasks, we study three important factors that can impact the quality of learned representations: pretraining data, the attention mechanism, and loss functions. By pretraining models on six datasets, we observe that dataset noise and language similarity to our downstream task are important indicators of model performance. Through architectural analysis, we learn that models with a multimodal attention mechanism can outperform deeper models with modality-specific attention mechanisms. Finally, we show that successful contrastive losses used in the self-supervised learning literature do not yield similar performance gains when used in multimodal transformers.

Electrical power systems energy saving and consumption reduction through transformer capacity and operation scheme

on the basis of summarizing the power loss of transformer, based on the optimal load rate of transformer or the principle of minimum comprehensive energy efficiency cost[1], the transformer capacity can be reasonably selected, so as to effectively reduce the increase of operation cost caused by too large or too small transformer capacity selection, and improve the energy saving and economy; After the transformer is selected, the economic operation scheme of the transformer can be used to arrange the operation[2], including making the transformer work in the economic operation section, economic switching among various operation modes of the transformer, economic distribution among transformer loads, etc.

Chaotic Modeling of Ferroresonance with Single-Phase Open in a Three-Phase System and Its Fractional-Order Control

In this study, a chaos-theoretic method is proposed to model the case of ferroresonance that can occur under nominal conditions in power systems, and the factors that determine the types of ferroresonance to occur are examined. In the ferroresonance chaotic system modeled in Matlab environment, the length of the transmission line and the breaker capacities in the circuit are fixed and its relationship with the transformer efficiency is investigated. In the proposed chaotic modeling, considering the situations that may occur in practical applications, the ferroresonance situations that occur when the single-phase remains open in the three-phase system are examined. In the study, ferroresonance, which occurs when one phase is open in a three-phase system, is analyzed by considering the situations that may happen during practical implementations. The similarity between the mathematical expressions obtained from the systems that create ferroresonance and Duffing oscillator is evaluated. In the chaotic system, fundamental ferroresonance, subharmonic ferroresonance, and chaotic ferroresonance situations are created depending on the transformer loss. Additionally, ferroresonance that occurs when the chaotic system is of fractional-order is analyzed, and it is observed that results of ferroresonance with different fractional-order values are not different. The results show that transformer loss is a significant element to determine the type of ferroresonance in power transformers. Also, when the chaotic system is operated in the fractional-order setting, the ferroresonance cases that occur are re-examined, and it is observed that the system can exit from the chaotic situation and prevent the formation of ferroresonance when fractional-order control is applied. According to the results, the fractional-order method can be used to control ferroresonance.

Pilot Study of Imatinib Discontinuation in Patients with Chronic Myeloid Leukemia with Deep Molecular Response (EDI-PIO) — Evaluation of Pioglitazone in Treatment-Free Remission

Introduction: Successful TKI discontinuation is feasible in approximately 40-60% of CML patients with stable and deep molecular response, but the persistence of quiescent CML stem cells (LSC) may be responsible for relapse. Pioglitazone, a PPARgamma agonist may reduce STAT5 activity and cause an erosion of CML LSC.Objectives: to evaluate safety and efficacy of pioglitazone in treatment-free remission (TFR) after imatinib discontinuation in patients with CML treated with pioglitazone for 3 months before imatinib discontinuation.Patients and methods: prospective, phase II trial. Inclusion criteria: CML in chronic phase, treated with imatinib for at least 3 years, with CCyR and stable deep molecular response (MR4.5) for at least 2 years. Patients received pioglitazone 30 mg/day, orally, for 3 months before imatinib discontinuation. BCR-ABL levels were measured by real-time quantitative PCR monthly for 12 months, every two months for 12 months, and then every 3 months during the subsequent follow-up. Imatinib was reinitiated at molecular relapse, defined as any single sample with a value of >0.1% (loss of major molecular response - MMR) or two consecutive positive samples with a value >0.01% (loss of MR4.0). Treatment-free remission (TFR) was calculated from imatinib discontinuation until molecular relapse, resumption of imatinib by any cause, progression to advanced phases or death to any cause.Results: Recruitment is ongoing. Between June 2016 and July 2017, 21 chronic phase CML patients were included. Median age was 48 years (23-65) at CML diagnosis and 56 years (29-76) at trial initiation; 52.4% male; Sokal: 62.5% low risk, 25% intermediate, 12.5% high risk; 14% treated previously with IFN. Two patients had diabetes and were using hypoglycemic drugs. The median time between diagnosis and imatinib start was 2 months (1-39); the median duration of imatinib treatment was 8.2 years (4-12). Nineteen patients received pioglitazone for 3 months and discontinued imatinib and two are still using both. There were no grade 2 or 3 adverse events related to pioglitazone; one patient did not complete the first month of pioglitazone treatment due to worsening of edema and went to discontinuation phase. The median follow-up of the 20 patients that discontinued imatinib was seven months (0-11). One patient dropped out of the trial and was censured in the analysis. Seven/18 patients (38%) presented newly or worsening musculoskeletal pain or arthralgia grades 1-2 occurring within 1-6 months after imatinib discontinuation. The two diabetic patients presented increase in glucose levels (grade 2 and 3), seven and eight months after imatinib discontinuation. There was no loss of hematological response or transformation to advanced phases. However, 4/18 (22%) patients (all male) reinitiated imatinib after molecular relapse: 1 lost MMR and CCyR response; 2 lost MMR, one had confirmed loss of MR4. Two of them recovered RM4.0 in 2 and 3 months after imatinib reintroduction. TFR was 74% (95% CI: 52-96%) in 9 months. TFR was higher in female patients (100% vs. 45%, P=0.019).Conclusion: Pioglitazone was well tolerated in the majority of the patients. The rate of withdraw syndrome was similar to the reported in other discontinuation trials. Increase in glucose levels was observed in two patients with diabetes after imatinib discontinuation. TFR was higher in female patients. A longer follow-up is necessary to evaluate the duration of TFR.This trial is registered in ClinicalTrials.gov (NCT02852486) DisclosuresPagnano:Bristol-Meirs Squibb: Consultancy, Speakers Bureau; Roche: Speakers Bureau; Amgen: Consultancy; Novartis: Consultancy.

Pengaruh Ketidakseimbangan Beban Terhadap Efesiensi Transformator Distribusi Studi Gardu PT PLN (PERSERO) Area Bekasi

Load unbalance in an electric power system often occur to meet consumer needs. Distribution of the load that was initially evenly will experience an unbalance when the burdens. As a result, current arises in the transformer neutral, current flowing in the transformer neutral causes losses, losses in the neutral conductor transformer and current flowing to the ground. Technically, if these losses occur continuously, it will be detrimental to PLN and can reduce transformer efficiency. For the supply of electricity to remain stable and continuity, it must be overcome

Evaluation of Errors of the Wattmeter Method for Determining Magnetic Losses in Transformers

Evaluation of Errors of the Wattmeter Method for Determining Magnetic Losses in Transformers

Precise appraisement of the harmonic loads impact on hysteresis losses in a 3-phase HTS transformer

Nowadays, the application of non-linear loads such as, rectifiers, electronic phase control, PWM drives, gives rise to a vastly increased level of harmonics in the power network. As such, the transport currents of transformers are non-sinusoidal alternating currents. On the other hand, AC losses are one of the most critical characteristics for the design and operation of high-temperature superconducting (HTS) transformers. The amount of hysteresis losses is a key parameter for the design of HTS windings affecting equipment, cooling cost, efficiency, and transformer economic feasibility. The computation of AC losses by traditional techniques, is suitable for the sinusoidal current condition. While, non-linear loads brings about different number of peaks and amplitudes in the current waveform passing through the HTS transformer windings. So that, in addition to the major hysteresis loop, a number of minor hysteresis loops are also formed changing the hysterical nature of the AC losses.Hence, this paper proposes an accurate, yet efficient analytical algorithm, for calculating hysteresis losses in a three-phase HTS transformer's windings in the presence of the harmonic loads accounting for the AC losses estimation. This is accomplished by performing a numerical Finite Element Method to verify the analytical results. The analysis of the hysteresis losses in an exemplary 315 kVA three-phase HTS distribution transformer for different harmonic loads, is another object of this paper.

Effect of Frequency on Eddy Losses of Transformers

Transformer is a vital component of electrical power systems for transmission and distribution. Robust design to increase the efficiency of a transformer is one of the main factors in transformer manufacturing. The efficiency of a practical transformer is limited by the losses caused by design and manufacturing defects. Losses in transformers can be divided into idle losses and losses under load. Eddy current loss is obtained from the idle losses of the transformer. In this paper, the effect of eddy effect causing HV energy loss at high magnetization frequencies was investigated. ANSYS@Maxwell software based on the Finite Element Method was used to analyze the eddy current loss in a T-connected, 3-leg and 3-phase distribution transformer of 15 MVA. The losses are obtained from no-load tests by changing the operating frequency of the transformer. Depending on the frequency value in the range of 50-60 Hz, the change in eddy current loss has been observed while the transformer winding is excitation at 1.74 T magnetic flux density. It has been observed that increasing the frequency causes an increase in the no load loss in the 3-phase transformer.