Maximum Power Loss Research Articles

Performance analysis of partially shaded high-efficiency mono PERC/mono crystalline PV module under indoor and environmental conditions

The ever-increasing demand for sustainable energy has drawn attention towards photovoltaic efficiency and reliability. In this context, the shading and associated hotpot degradation within PV modules has become an important area of research and development. The experimental approach of this paper aims to investigate single cell shading in high efficiency monocrystalline silicon PV PERC modules. Prior to the outdoor experiment, the PV module underwent experimental testing under STC to determine variation in electrical and thermal behaviour due to partial shading. The indoor experiments are performed using Sun-simulator and the I–V and P–V curves are analysed. Further, the outdoor experiments were performed under realistic conditions. In both cases, results showed that during 40–60% shading in single cell leads to critical shading scenario causing significant drop in power output in comparison with their unshaded conditions. The maximum power loss of 36.34% and 42% is recorded for indoor and outdoor experiments. The outdoor experiments recorded hotspot temperature of 85–90.1 °C under respective 40% and 60% critical shading scenarios. The efficiency recorded in the time interval of 11:00:00 and 11:30:00 was highest for the solar radiations between 940 and 990 W/m2. The maximum drop in efficiency is recorded from noon till 13:30:00 time of the day. Development of hotspot is directly related to the failure or malfunction of protecting system. Hence the importance of type of PV technology, amount of shading, and critical shading scenario is presented in the study. This study is important for researcher and manufacture to consider single cell shading in PV technology.

Study on the Optical Coupling Effect of Building-Integrated Photovoltaic Modules Applied with a Shingled Technology

Building-integrated photovoltaics (BIPV) comprise the integration of a solar power generation system into the exterior design and architectural elements of a building to produce electricity, which allows the building itself to generate electricity. By integrating shingled technology into the photovoltaic module with optimization of the optical effect, the output performance of the module can be increased while securing an aesthetic appeal as an architectural exterior material for the building simultaneously. In this research, we studied enhancing the performance of BIPV modules through an analysis of the optical coupling effect for shingled technology using PSpice simulation. Compared to the efficiency of 0.2 cm string spacing, the optical coupling effect was increased by 33.33%, 46.98%, 67.01%, and 193.49% according to the string spacing of 0.5 cm, 1 cm, 2 cm and 4 cm, respectively. To analyze this increase, we focused on studying the increase in current due to the reflection and re-absorption of light in the back layer of the solar cell as the cause of this output enhancement. Additionally, the coupling effect in accord with different layers showed that using white EVA to reflect the incident light from the top layer resulted in 117.14% and 521.90% enhancements in maximum output power (Pm) loss % compared to the conventional and black backsheet applied PV modules, respectively.

Deployment of Lifetime Cost Analysis to Reassess Economic Current Density in the Presence of Vietnam’s Market Economy

A decent choice of conductor size for overhead power transmission lines can provide economic advantages throughout the project’s lifetime. One of the crucial criteria for sizing conductors is economic current density. In Vietnam, the electricity industry has extensively utilized the 1950s-era economic current density that ignores the value of cash flow at diverse points in time and applies the assumption of the constant electricity tariff and wire cost. These costs, nonetheless, are likely to greatly impact the figures of economic current density; as a result, these figures must be modified. This paper puts forward novel figures of economic current density that are systematically determined on the basis of lifetime cost (LTC) analysis in the presence of Vietnam’s market economy. The LTC is made up of the initial capital expenditure (ICE) and the overall operating cost (OPC), which includes the expense incurred for maintenance and electricity energy loss. An analytical formulation of ICE related to conductor size and system voltage is established based on information from recently built overhead transmission lines and a regression-based method. The electricity energy loss is computed based on equivalent hours of maximum power loss contingent upon equivalent hours of maximum power usage throughout an analytical expression obtained on the basis of the regression technique from load consumption patterns in the past. Finally, the feasibility and efficacy of the proposed economic current density values are validated by practical case studies of overhead transmission lines in Vietnam. The deployment of the suggested strategy demonstrates a decrease in lifetime cost ranging from approximately 5% to around 20% in comparison to the methodology prescribed by the existing Vietnam standard.

Harmonics management and hosting capacity enhancement: Optimal double-resistor damped double-tuned power filter with artificial hummingbird optimization.

This paper introduces a novel and improved double-resistor damped double-tuned passive power filter (DR-DDTF), designed using multi-objective optimization algorithms to mitigate harmonics and increase the hosting capacity of distribution systems with distributed energy resources. Although four different topologies of single-resistor damped double-tuned filters (DDTFs) have been studied before in the literature, the effectiveness of two different DR-DDTF configurations has not been examined. This work redresses this gap by demonstrating that via comprehensive simulations on two power systems, DR-DDTF provides better harmonic suppression and resonance mitigation than single-resistor alternatives. When it comes to optimizing the DR-DDTF for maximum hosting capacity and minimum system active power losses, the multi-objective artificial hummingbird outperformed six other algorithms in the benchmark. To allow for higher penetration of distributed generation without requiring grid upgrades, this newly developed harmonic mitigation filter provides a good alternative.

Research on the Application of Multi-Physics Field Coupling Simulation in the Analysis of Temperature Field of 500kv GIS Circuit Breaker

Gas insulated switchgear (GIS) is a crucial part of any electrical infrastructure. Overheating the conductor on the GIS busbar would reduce the effectiveness of the insulating gas and shorten the life of the device. We then maximize output by fine-tuning the busbar's rotation angle, central distance, and conductor thickness. Dependable electrical systems always include gas insulated transmission lines (GIL) and gas insulated switchgear (GIS). Because of their reduced total cost and greater efficiency in terms of both space use and power transmission, GILs are gradually replacing conventional overhead lines for long-distance, high-power transmission. The reliability of GIL performance and the ease with which designs can be optimized necessitates research into their power loss and temperature profiles. The study found that the maximum temperature and power loss variances were approximately 70% attributable to differences in conductor thickness. By employing the aforementioned combination method (A1, B5, C5), energy consumption and thermal load in the GIS can be reduced. The research also shows that SF6 gas retains its outstanding insulating capacity after undergoing structural optimization. The calculation of the gas breakdown margin demonstrates this. In conclusion, the results of this study contribute to the understanding of heat transmission in three-phase GIS busbars and their optimization and engineering. Examining the temperature field of 500kV GIS circuit breakers, it highlights the value of multi-physics field coupling simulations in improving the reliability and performance of power system components, especially GILs. This is done so that power system components are more reliable and run more efficiently. Optimal heat transmission and other design considerations for three-phase GIS busbars are the most important takeaways from this research.

Buyer aware: Three new failure modes in TOPCon modules absent from PERC technology

The n-type tunnel oxide passivated contact (TOPCon) technology is going to be the leading industrial technology in 2024. However, there are still concerns about the reliability of TOPCon when used in the field, especially in glass/backsheet modules. This work investigates the impact of damp heat (DH) on the performance TOPCon and PERC glass/backsheet modules by varying bills of materials (BOM), such as polyolefin elastomer (POE), ethyl-vinyl acetate (EVA), and polymer backsheet options. It is found that PERC modules remain stable, with a maximum power loss (Pmax) of only 1–2%rel after 1000 h of DH testing, regardless of the BOM used. However, TOPCon modules experienced significant degradation with a drop in Pmax ranging from 4 to 65%rel after the same testing duration. Despite utilizing POE, an expensive encapsulant with a significantly lower water vapour transmission rate than EVA and devoid of acetic acid formation, a severe performance decline was observed in a specific POE variant within TOPCon modules, with a loss of power of up to 65%rel. Three types of failures were observed in TOPCon modules: point-localized failure, failure at/around the interconnection of ribbon wires and busbars, and failure throughout the whole area of cells/modules. These failures likely result from electrochemical reactions involving moisture, cell metallization, ribbon wires, contaminants, soldering flux, and additives released from POE. The observed findings underline two crucial points: 1) the vulnerability and potential failure of TOPCon solar cells when exposed to high humidity and contaminants, and 2) the high risk associated with certain POE types, which could potentially adversely affect TOPCon cells. Hence, it is crucial to exercise utmost caution and precision in handling and selecting encapsulation materials for TOPCon modules. Accordingly, urgent and extensive research efforts are crucial to substantially increase our comprehension and fortify the reliability of TOPCon cells against the pernicious effects of moisture and other contaminants.

PERFORMANCE OF SCREW HORIZONTAL AND BRIDGE LINKAGE PHOTOVOLTAIC ARRAY CONFIGURATIONS

Due to partial shading effects on the productivity of solar panels which in turn negatively impacts the performance characteristics of photovoltaic systems, researchers work on different studies to overcome this phenomenon and improve solar system productivity. Therefore, this study aims to investigate different techniques to enhance the output power, fill factor, and efficiency of the PV system by reducing the number of local maximum power peaks, power losses, and mismatch losses. The configurations include a novel static reconfiguration technique, called a Screw Horizontal photovoltaic array, and a recently developed technique known as a Bridge Linkage array. Both of these are modeled using MATLAB/Simulink software and examined during six shading patterns. The novelty of this study is that we combined the above static reconfiguration technique with another modern technique called blocking and bypass diode technology to prevent the effect of reverse current and hotspot phenomena respectively. According to the results, the Bridge Linkage configuration performs the most efficiently under partial shading conditions compared to the Screw horizontal PV array configuration.

Optimal Design and Operation of Wind Turbines in Radial Distribution Power Grids for Power Loss Minimization

This research proposes a strategy to minimize the active power loss in the standard IEEE 85-node radial distribution power grid by optimizing the placement of wind turbines in the grid. The osprey optimization algorithm (OOA) and walrus optimization algorithm (WOA) are implemented to solve the problem. The two algorithms are validated in three study cases of placing two wind turbines (WTs) in the system for power loss reduction. Mainly, in Case 1, WTs can only produce active power, while in Case 2 and Case 3, WTs can supply both active and reactive power to the grid with different ranges of power factors. In Case 4, the best-applied methods between the two are reapplied to reach the minimum value of the total energy loss within one year. Notably, this case focuses on minimizing the total power loss for each hour in a day under load demand variations and dynamic power supply from WTs. On top of that, this case uses two different sets of actual wind power data acquired from the Global Wind Atlas for the two positions inherited from the previous case. Moreover, the utilization of wind power is also evaluated in the two scenarios: (1) wind power from WTs is fully used for all values of load demand, (2) and wind power from WTs is optimized for each load demand value. The results in the first three cases indicate that the WOA achieves better minimum, mean, and maximum power losses for the two cases than the OOA over fifty trial runs. Moreover, the WOA obtains an excellent loss reduction compared to the Base case without WTs. The loss of the base system is 224.3 kW, but that of Case 1, Case 2, and Case 3 is 115.6, 30.6 kW, and 0.097 kW. The placement of wind turbines in Case 1, Case 2, and Case 3 reached a loss reduction of 48.5%, 84.3%, and 99.96% compared to the Base case. The optimal placement of WTs in the selected distribution power grid has shown huge advantages in reducing active power loss, especially in Case 3. For the last study case, the energy loss in a year is calculated by WSO after reaching hourly power loss, the energy loss in a month, and the season. The results in this case also indicate that the optimization of wind power, as mentioned in Scenario 2, results in a better total energy loss value in a year than in Scenario 1. The total energy loss in Scenario 2 is reduced by approximately 95.98% compared to Scenario 1. So, WOA is an effective algorithm for optimizing the placement and determining the power output of wind turbines in distribution power grids to minimize the total energy loss in years.

Swarm intelligence technique for solving optimal power flow problem in the Nigeria power system

This paper deals on the implementation of the particle swarm optimization method for solving power flow problems in the Nigeria power system. The difficulty of solving optimal power flow (OPF) problems increases significantly with increasing network size and complexity. Some of the weakness of the conventional methods include: limited ability in solving real-world large scale optimization problems, weakness in handling constraints, poor convergence and slow computational time. The results gotten by implementing the Particle Swarm Optimization (PSO) algorithm in Nigeria 330kV 52-Bus network show that the total active power and reactive power losses were substantially reduced to 0.03MW and 0.05MVAR. The system time of convergence was faster at 0.5seconds. Also, the maximum line active and reactive power losses on line 1 to 2 were reduced greatly to 0.00MW and 0.01MVAR respectively. These show that the system was better optimized with the PSO algorithm than the conventional method.

Accelerated damp-heat testing at the cell-level of bifacial silicon HJT, PERC and TOPCon solar cells using sodium chloride

Bifacial passivated emitter and rear cells (PERC) currently have the highest share in the photovoltaic market. However, heterojunction (HJT) and tunnel oxide passivated contact (TOPCon) solar cells are expected to gain significant market share shortly. Despite technological advancements, concerns about the reliability of HJT and TOPCon technologies when deployed in the field still need to be addressed. This work investigates the impact of sodium chloride (NaCl) on damp-heat-induced degradation in bifacial HJT, PERC, and TOPCon solar cells by exposing the solar cells to NaCl before damp heat (DH) testing. It is found that among all investigated cell technologies, TOPCon solar cells degrade the most with maximum power (Pmax) loss of up to ∼75%rel, followed by HJT (Pmax drops ∼50%rel), and PERC cells (Pmax drops only ∼10%rel) after 20 h of DH testing, mainly attributed to an increase in Rs on the front side of TOPCon cells, both sides of HJT cells and the rear side of PERC cells. The front of the PERC and the rear of the TOPCon solar cell are found to be stable. The rise in Rs is attributed to the corrosion of the metal contact, which is caused by a high amount of Na+ and Cl− ions penetrating the metal contact. This corrosion leads to increased porosity, detachment of the contact from the silicon interface, and increased recombination loss in some cases. These results are crucial for all cell technologies as they highlight the potential failures that could occur in the field. Na+ and/or Cl− ions are common contaminants present in solar glass, human fingerprints, soldering flux, rainwater, soil/dust, and seawater. During field operation, these ions have the potential to penetrate and directly interact with solar cells. In our view, the preferred solution is for the solar cells to be corrosion-resistant, which can be rapidly assessed using the method presented in this work.

Four failure modes in silicon heterojunction glass-backsheet modules

Silicon heterojunction technology (HJT) is expected to gain a significant market share in the near future. For HJT to deliver a low levelized cost of electricity (LCOE), it needs to have a high initial efficiency and degrade less than 0.5% relative per year. This work investigates damp heat-induced failure modes in silicon HJT glass-backsheet modules. Four unique failure modes are identified after damp heat (DH) testing: point failure (Type-1); failure around the interconnected regions of the busbars and ribbon wires (Type-2); failure between the busbars (Type-3); and failure at/on the interconnected regions of busbars and ribbon wires (Type-4). The Type-1 failure mode is likely caused by a chemical reaction between surface contaminants (introduced to the cells during handling or characterization before encapsulation) and moisture that increase charge carrier recombination and lead to a loss in maximum power (Pmax) of up to 40%rel in this study. Type-2 and Type-3 failure modes cause Pmax losses of ∼5%rel and 50%rel, respectively, in this study and can appear due to exposure to soldering flux used for connecting the ribbon wires and busbars. Finally, the Type-4 failure mode causes a Pmax loss of ∼16%rel in this study after the DH test. The evidence suggests that this failure mode is likely due to the interaction of acetic acid, generated from a reaction between the encapsulation material and moisture, ribbon wires, and silver paste (busbars), resulting in recombination loss. We believe these failure modes must be well understood and mitigated at preferably the solar cell level to ensure that HJT can meet its LCOE potential.

Hardware implementation of proposed and conventional PV array reconfiguration techniques to extract maximum power under various shading conditions

SummaryThe unpredictability of partial shadowing impacts the solar photovoltaic system's performance. This results in mismatch losses, reducing the healthy PV module's power output. This paper proposes a new reconfiguration method to increase the power generation of an array by lowering the power losses. A new physical relocation technique named the magic matrix shifting (MMS) method has been introduced in this paper. This work uses MATLAB/Simulink to model a 36, 213w, 6 × 6 PV array construction. Under six different partial shading situations, the performance has been examined based on P‐V, I‐V characteristics, maximum power extraction, power loss, and percentage. For comparison purposes, conventional total‐cross‐tide (TCT) and six other reconfigurations, including sudoku (SK), optimum sudoku (OSK), zig‐zag (ZZ), magic square (MS), sky‐scraper (SS), and novel shade dispersion (NSD) have been considered.

Effects of Stochastic Noises on Limit-Cycle Oscillations and Power Losses in Fusion Plasmas and Information Geometry

We investigate the effects of different stochastic noises on the dynamics of the edge-localised modes (ELMs) in magnetically confined fusion plasmas by using a time-dependent PDF method, path-dependent information geometry (information rate, information length), and entropy-related measures (entropy production, mutual information). The oscillation quenching occurs due to either stochastic particle or magnetic perturbations, although particle perturbation is more effective in this amplitude diminishment compared with magnetic perturbations. On the other hand, magnetic perturbations are more effective at altering the oscillation period; the stochastic noise acts to increase the frequency of explosive oscillations (large ELMs) while decreasing the frequency of more regular oscillations (small ELMs). These stochastic noises significantly reduce power and energy losses caused by ELMs and play a key role in reproducing the observed experimental scaling relation of the ELM power loss with the input power. Furthermore, the maximum power loss is closely linked to the maximum entropy production rate, involving irreversible energy dissipation in non-equilibrium. Notably, over one ELM cycle, the information rate appears to keep almost a constant value, indicative of a geodesic. The information rate is also shown to be useful for characterising the statistical properties of ELMs, such as distinguishing between explosive and regular oscillations and the regulation between the pressure gradient and magnetic fluctuations.

Accelerated UV stress testing and characterization of PV-modules: Reliability analysis using different encapsulants and glass sheets

Ethylene vinyl acetate (EVA) is the most commonly used encapsulant material in photovoltaic (PV) module fabrication. However, during long-term operation in the field under hot and dry climates, it turns yellow and finally brown due to action of ultraviolet (UV) light. Therefore, UV-light is a major concern causing photodegradation of encapsulant and significant loss in maximum power (Pmax) of PV-module. The main objective of this study is to provide deeper insights into degradation of electrical parameters in PV-modules under influence of UV-light and temperature, and minimize the impact of UV induced degradation (UVID) by replacing the encapsulant EVA with poly vinyl butyral (PVB). Four polycrystalline PV-modules, fabricated in different combinations from two types of encapsulants, namely PVB and EVA, and glass sheets, namely soda-lime and quartz, are subjected to an accelerated UV stress test for 350 h. Visual inspection, electroluminescence, infrared imaging, insulation resistance, wet leakage current, and maximum power determination tests were performed to characterize PV-modules intermittently throughout accelerated UV stress test. Based on obtained electrical parameters, PVB/soda-lime experienced the lowest 3% loss in Pmax, whereas EVA/quartz experienced the highest 7% loss in Pmax. In other two samples, EVA/soda-lime and PVB/quartz, Pmax reduced by 4% and 5% respectively.

Long-term over-the-horizon microwave channel measurements and statistical analysis in evaporation ducts over the Yellow Sea

Maritime high-speed over-the-horizon wireless communication is realizable through evaporation ducts. Detailed measurement, analysis, and modeling of duct channels are essential for application of this communication technique. In this paper, X-band electromagnetic (EM) wave propagation systems were developed and deployed for a 133-km over-the-horizon microwave link in coastal areas of the Yellow Sea. The propagation length was 7.7 times the line-of-sight length. Measurement results including the path loss (PL) and meteorological data were obtained during a 54-day period in autumn 2021. The long-term channel results were analyzed on the basis of statistical analysis and model simulations. Results showed that our measurement system, with a maximum measurable power loss of 200 dB, had connected with a probability of 56.2% during the measurement period. Model simulation showed that evaporation duct environments are not ideal in autumn, with an average evaporation duct height (EDH) of 10.6 m. The land breeze in autumn introduced dry and cold air to the link, which could promote evaporation of seawater and reduce PL by approximately 40 dB. Annual spatiotemporal characteristics of EDH showed that evaporation ducts are most suitable for over-the-horizon communication in spring, especially May.

DPVM-SEC based methodology to reconfigure PV system and characterization during PSCs: Experimental study using data acquisition system

Partial shadowing produces significant hindrance to the efficient use of solar photovoltaic (PV) system. Partial shading conditions (PSCs) reduce PV system performance and show the highly non-linear behavior with respect to power-voltage (P-V) graphs.. A DPVM- SEC , 6 × 4 size array is suggested in the manuscript to reduce the impacts of shadowing on PV arrays. Also, the efficiency of the traditional arrangements, series–parallel (SP) and total-cross-tied (TCT) are analyzed and compared with the dynamic PV module with static electrical connections (DPVM- SEC ). Various performance indices such as power and voltage at global maximum power point (GMPP), power loss (PL) and fill factor (FF) are evaluated to demonstrate that the DPVM- SEC based method is the appropriate configuration for eliminating the shading impacts. Furthermore, an ATmega-328 microcontroller-based data acquisition system (DAS) is developed to measure the real-time electrical parameters. The experimental study demonstrates the feasibility to characterize the PV system with accuracy and less time taken processes. In this paper, the design of DAS is very useful for new learners and affirms the feasibility to use in further related PV system characterization study under shading conditions.

Reduction of Active and Reactive Power Losses on Transmission Lines using SSSC

This paper discusses a comprehensive study on reduction of power (active and reactive) losses in transmission lines using a second generation FACTS device, Static Synchronons Series Compensator (SSSC). Modern restructured power systems sometimes operate with heavily loaded lines resulting in power losses and higher voltage deviations, which may lead to mal-operation of power system and eventual collapse of the system. This is mainly due to continuous and uncertain growth in demand for electrical power. The paper presents a methodology to solve the problem of power losses in the Nigerian 28 – bus power system by incorporating Static Synchronons Series Compensator in the network using Newton-Rahson power flow algorithm. Simulation of power flow solution without and with the FACTS device was done using a Matlab software. The results showed that the maximum power (active and reactive) loss in the system without SSSC occurred in the transmission line connecting bus 17 (Jebba) to bus 23(Shiroro) and a 19.32% loss reduction was obtained on the line after the incorporation of the SSSC FACTS device giving a power saving of 80.68%. The total system active and reactive power losses before the application of SSSC was 205.183MW and 1594.683MVAR respectively. However, when the FACTS device was applied at the weak buses the total system active and reactive power losses reduced to 144.571MW and 1136.863MVAR respectively giving a percentage loss reduction in active and reactive power of 29.54% and 28.71% respectively resulting in a power saving of 70.46% and 71.29%. Hence, more power was available in the network when compared to the base case due to the installation of SSSC. Also an improvement in the voltage magnitude at the weak buses and other buses were noticed as they were all maintained at 1.0 PU.

Optimal Deployment of Unified Power Flow Controller on Nigerian 330 kV Grid Using Artificial Bee Colony

Transmission line power loss minimization and voltage profile improvement are challenging problems in modern power systems due to continuous increase in load demand. In this paper, an optimal location and sizing of unified power flow controller (UPFC) to improve the performance of the updated 54-bus 330 kV Nigerian network was presented. Here, the maximum power loss bus was identified to be the most favorable location for fixing the UPFC under different loading conditions; slightly underloaded (90%), normal loading (100%) and slightly over loaded (110%). The optimum location was determined using the artificial bee colony (ABC) algorithm. The work was implemented in MATLAB® 2021b environment and its performance was evaluated based on the simulation results obtained. The simulation results revealed that, ABC proved to be robust based on the facts that all the voltage profile that violate ± 5% tolerance margin of the nominal voltage criteria were kept within the acceptable limit after the UPFC optimal deployment. Moreover, the proposed approach also recorded significant reduction in the overall active and reactive power loss in the entire network with a minimum percentage average active power loss reduction of 45.3% under different loading conditions.

Minimization of Electric Power Losses on 132 kV and 220 kV Uganda Electricity Transmission Lines

The classical minimization of power losses in transmission lines is dominated by artificial intelligence techniques, which do not guarantee global optimum amidst local minima. Revolutionary and evolutionary techniques are encumbered with sophisticated transformations, which weaken the techniques. Power loss minimization is crucial to the efficient design and operation of power transmission lines. Minimization of losses is one way to meet steady grid supply, especially at peak demand. Thus, this paper has presented a gradient technique to obtain optimal variables and values from the power loss model, which efficiently minimizes power losses by modifying the traditional power loss model that combines Ohm and Corona losses. Optimality tests showed that the unmodified model does not support the minimization of power losses on transmission lines as the Hessian matrix portrayed the maximization of power losses. However, the modified model is consistent with the gradient method of optimization, which yielded optimum variables and values from the power loss model developed in this study. The unmodified (modified) models for Bujagali-Kawanda 220 kV and Masaka West-Mbarara North 132 kV transmission lines in Uganda showed maximum power losses of 0.406 (0.391) and 0.452 (0.446) kW/km/phase respectively. These results indicate that the modified model is superior to the unmodified model in minimizing power losses in the transmission lines and should be implemented for the efficient design and operation of power transmission lines within and outside Uganda for the same transmission voltages.

Experiment and Power Capacity Investigation for a Ku-Band Continuous-Wave Gyro-TWT

In this article, the design and experiment of a high continuous-wave (CW) power Ku-band gyrotron traveling-wave tube (gyro-TWT) are described. The hot experiment results indicate that the TE11 mode gyro-TWT, driven by a 50 kV–4.5 A electron beam, can produce a maximum CW output power of 49 kW, with an efficiency of 21.8% at 16 GHz. The saturated bandwidth is 2 GHz, and more than 30-kW CW output power is achieved from 15 to 17 GHz. However, the outgassing is observed in the low-frequency range, which limits the enhancement of CW output power. Then, the simulation is performed and indicates that the attenuated power distribution and heat dissipation on the dielectric-loaded circuit (DLC) are dependent on the frequency, attenuation of lossy ceramic, and input power. Also, the maximum temperature of lossy ceramic at 15 and 15.5 GHz is too high for stable operation. A nonuniform DLC is utilized to dissipate power dispersedly. The simulation results show that the maximum power loss on a single lossy ceramic is reduced by 77.9% and 48.9% at 15 and 15.5 GHz, respectively. It indicates that the nonuniform DLC could adjust the dissipation power on the lossy ceramics via the attenuation profile varying with frequency and effectively enhance the power capacity of dielectric-loaded gyro-TWT.