Maximum Allowable Power Research Articles

Restructured electricity market strategies for the Indian utility system using support vector regression and energy valley optimizer

Restructuring the electricity market has led to the establishment of a competitive open market environment. The electricity market has introduced uncertainty and risk in the economic sector conventionally owned by the state. The power generated in the generating station is transferred to the distribution side in the power markets, which share a common transmission network. The power transfer will be in bulk amounts and needed to operate the electricity market securely and economically. The bulk amount of power transfer relies on accurately estimating Available Transfer Capability (ATC), representing the maximum allowable power flow through the existing transmission network while maintaining system reliability. The estimation of the ATC using a proposed hybrid method. The hybrid method comprises Repeated Power Flow (RPF) and Support Vector Regression (SVR) methods. The electricity market participants such as sellers and buyers submit bids to maximize their profit with the help of ATC values. The linear bid function is proposed to formulate participant strategies. Each participant will submit the availability of power requirement and willing price in the linear bid function. The Energy Valley Optimizer (EVO) algorithm is proposed to maximize the profit of each participant. The EVO algorithm efficiently explores a vast solution space, considering complex constraints and uncertainties inherent in the market dynamics to enhance economic gains. The proposed work is tested on the practical UPSEB (Uttar Pradesh State Electricity Board) 75-bus Indian utility system.

Adaptive resource allocation in NOMA-enabled backscatter communications systems

The integration of NOMA with Backscatter communication (BackCom) is a promising solution for developing a green future wireless network. However, system performance degrades with the deployment of multiple backscatter devices (BDs) in a network. Hence, energy efficiency (EE) maximization with proper resource allocation is among the primary concerns. In this regard, this paper proposes an adaptive resource allocation method for maximizing EE by simultaneously optimizing the transmission power from the base station (BS), power allocation coefficients, and reflection coefficients under the constraints of maximum allowable transmission power and minimum achievable data rate. Specifically, an iterative method based on a parametric transformation approach is adopted for maximizing EE by jointly optimizing the coefficients, in which the power allocation problem to the BDs is solved by an adaptive method that is based on improved proportionate normalized least mean square (IPNLMS) algorithm. Then, the system performance is evaluated, and the impact of different parameters is also studied it is observed that EE is significantly improved as compared to the existing scheme, and maximum at <span>η</span>=-0.5.

Transmitter design and AE–AR region characterization for NOMA-SLIPT UWOC systems with uniformly distributed message and Imp-SIC

This paper investigates simultaneous lightwave and information transfer (SLIPT) based non-orthogonal multiple access (NOMA) in underwater optical wireless communication (UWOC) systems. At the user signal separation (SS) based SLIPT scheme is employed. Imperfect successive interference cancellation (SIC) at the near user is considered. Firstly, we derive the maximum allowable electrical power for message symbols at the transmitter, ensuring input to the laser diode lies within the linear region and. A novel linearity-constrained transmitter design is proposed for the uniformly distributed message, followed by calculations of instantaneous data rate and instantaneous harvested energy for both users. Then, closed-form expressions for average data rates (AR) and average energy harvested (AE) under weak turbulence-induced fading channels using Holtzman’s approximation are derived. The tightness of the approximation is confirmed by Monte-Carlo simulations. AE–AR boundaries for both users show an initial rise and subsequent decline in data rates with increased harvested energy, owing to higher bias values restricting transmitter power. The study also examines trade-offs between AE and AR across various system parameters including beam divergence angles, imperfection of SIC, power allocation coefficients, and water types, is conducted. We observe shifting and shrinking/expansion of the AE–AR region depending upon the variation of the various system parameters. We also show that the discussed SS scheme is general and encompasses time-switching (TS), and power-splitting (PS) schemes as special cases. We also briefly discuss as to how the developed framework could be extended to more than two users. In summary, the overall effective energy consumption deduces owing to the adoption of SLIPT at the users, making the considered setup more energy-efficient.

Drawbacks of a medium sized, grid coupled Photo Voltaic Array

A medium sized photo voltaic (PV) array with good inverters produces high quality, real (true) power.. The maximum allowable reactive power is a percentage of the real power consumed from the grid. Before the PV array was installed the reactive power was less than 50% of the real power, which is allowed by the by-laws. Because of the amount of PV generated real power the actual consumed real power reduced. The ratio of reactive power to the consumed power changed therefore drastically. According the by-laws and the utility the eactive power drawn from the power grid is too high and the owner of the PV installation now has to pay a fine.

A Simulation-Assisted Proactive Scheduling Method for Secure Microgrid Formation Under Static and Transient Islanding Constraints

Microgrids (MGs) provide a promising solution to ensure the constant power supply under extreme conditions due to their islanding ability. However, unintentional islanding caused by emergencies may trigger significant a power imbalance in MGs, leading to unsuccessful MG formation in the event that static or transient operational constraints are violated. To address this challenge, we propose a proactive distribution system scheduling method to continue serving critical loads in emergencies by forming reliable MGs. The power flow on the lines is restricted prior to interruption to mitigate the power imbalance in MGs when equipment failures occur. Both static and transient constraints are incorporated into the proposed model to ensure the adequacy of MGs in supplying demands and transient security during the islanding transition. Note that the inclusion of nonlinear transient constraints makes it difficult to solve the model directly. Thus, a two-level simulation-assisted solution approach is presented, where simulation level sends the maximum allowable power imbalance in the MGs to optimization level to determine optimal scheduling schemes. By interfacing with a transient simulation of MGs, the frequency dynamics are exactly incorporated into the constraints. Numerical results validate the effectiveness of the proposed method in secure islanding transition and MG survivability improvement.

On the Study of Interference Scenario on TV Broadcast and Wireless Systems for Emergency Communication Networks in TVWS

This paper investigated frequency sharing between primary TV systems (channels 32 and 49) and Emergency Communication Networks (ECNs). The networks to be implemented in the Osogbo axis of Osun State function on a secondary geographical basis, creating no harm to the original licensed primary TV viewers. A minimum separation distance of 41 dB was suggested as the protected contour for the UHF spectrum to oversee the protection of primary TV users for the UHF bands under consideration. The effects of changing the secondary systems' transmitting power, transmission frequency, and antenna height on the service coverage distance were also explored. The performance of the UHF band was evaluated when it was utilized for secondary transmission at both low and high transmitting powers, with the performance criterion being percentage coverage distance. This work complies with the International Telecommunication Union-Radio sector (ITU-R) recommendations of 16 dB for signal-to-noise ratio and 41 dB for signal strength. It can also be deduced from the result that when the transmission power of ECN devices is raised from 40 mW to 4 W, Effective Isotropic Radiated Power (EIRP) is used; it caused a 76.19% reduction in the coverage spacing for TV channels of ECN Network secondary devices. For the White Space Device (WSD) to operate in Temporal mode, the maximum allowable power (4 W) used in spatial mode should be replaced by a 76.19 per cent reduction. Additional sensing margins of 3.76 dB and 4.04 dB for channels 33 and 43 must be added to the FCC threshold limit of -114 dBm criterion for TV white spaces to assure ECN deployment without causing severe interference to TV customers.

Comparative Analysis of Smart Grid Solar Integration in Urban and Rural Networks

Solar photovoltaic (PV) power, a highly promising renewable energy source, encounters challenges when integrated into smart grids. These challenges encompass voltage fluctuations, issues with voltage balance, and concerns related to power quality. This study aims to comprehensively analyze the implications of solar PV penetration in Malaysian power distribution networks predominantly found in urban and rural areas. To achieve this, we employed the OpenDSS 2022 and MATLAB 2022b software tools to conduct static power flow analyses, enabling us to assess the effects of solar PV integration over a wide area under two worst-case scenarios: peak-load and no-load periods. Our investigation considered voltage violations, power losses, and fault analysis relative to the power demand of each scenario, facilitating a comprehensive evaluation of the impacts. The findings of our study revealed crucial insights. We determined that the maximum allowable power for both urban and rural networks during no-load and peak-load situations is approximately 0.5 MW and 0.125 MW, respectively. Moreover, as the percentage of PV penetration increases, notable reductions in power losses are observed, indicating the potential benefits of higher smart grid PV integration.

Multiconductor Cell Analysis of AC High Speed Railway Lines

The aim of this paper is the application of Multiconductor Cell Analysis to a very special case of a multiconductor system, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i.e</i> ., the AC high-speed railway system, with 14 parallel conductors. The present matrix approach allows representing both the single elements and the entire railway system also including the high voltage three-phase supply network. The algorithm allows computing all the steady-state regime electrical quantities (voltages, currents and power) of each section: in particular, the ground return current, responsible for electromagnetic interferences, can be derived by the knowledge of all the circulating currents. It is also possible to evaluate the electric unbalance impact on the supply three-phase power system given by the railway system. Eventually, two different scenarios are presented, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i.e</i> ., a maximum allowable high-speed line power request and a contact-wire to rail short circuit.

A Compact-Size Multiple-Band Planar Inverted L-C Implantable Antenna Used for Biomedical Applications.

In this paper, a compact-size multiple-band planar inverted L-C implantable antenna is proposed. The compact antenna has a size of 20 mm × 12 mm × 2.2 mm and consists of planar inverted C-shaped and L-shaped radiating patches. The designed antenna is employed on the RO3010 substrate (εr = 10.2, tanδ = 0.0023, and thickness = 2 mm). An alumina layer with a thickness of 0.177 mm (εr = 9.4 and tanδ = 0.006) is used as the superstrate. The designed antenna operates at triple-frequency bands with a return loss of -46 dB at 402.5 MHz, -33.55 dB at 2.45 GHz, and -41.4 dB at 2.95 GHz, and provides a size reduction of 51% compared with the conventional dual-band planar inverted F-L implant antenna designed in our previous study. In addition, the SAR values are within the safety limits with a maximum allowable input power (8.43 mW (1 g) and 47.5 mW (10 g) at 402.5 MHz; 12.85 mW (1 g) and 47.8 mW (10 g) at 2.45 GHz; and 11 mW (1 g) and 50.5 mW (10 g) at 2.95 GHz). The proposed antenna operates at low power levels and supports an energy-efficient solution. The simulated gain values are -29.7 dB, -3.1 dB, and -7.3 dB, respectively. The suggested antenna is fabricated and the return loss is measured. Our findings are then compared with the simulated results.

POWER AMPLIFIER BASED ON COMPOSITE INJECTION-VOLTAIC TRANSISTORS

The problem of high-current radio engineering devices is related to the fact that the use of high-power transistors and other semiconductor devices is limited by such a phenomenon as a secondary breakdown, in which there is a sharp decrease in the voltage on the device with simultaneous internal current lacing, and the device fails. To solve the problem of secondary breakdown, schemes have been proposed that operate stably at reverse voltage values 4-5 times higher than usual and at power dissipation 2-3 times higher than the maximum allowable power for an individual device. The problem is proposed to be solved by using composite transistors. This is the most optimal way, since passive elements are not used.

Determination of the maximum allowable active powerflow in the section taking into account the thermal conditions of power transmission lines

Subject of research: This paper assesses the possibility of introducing into the task of calculating maximum and emergency allowable active power flow, taking into account the thermal modes of overhead lines when planning electric power regimes. &#x0D; Purpose of research: determine the effect of thermal processes in power lines on the maximum allowable active power flow in controlled sections of electric power systems.&#x0D; Methods and objects of research: Such factors influencing active power flow as ambient air temperature, which is currently corrected by the Russian Power System Operator, wind speed, solar radiation and direct heating from flowing current are considered. Simulation of steady state flow in the software package RastrWin3 and Mathcad for a 2-bus scheme with mode only taking into account the ambient temperature and the calculations of steady state flow were already taking into account variations in weather parameters, taking into account possible restrictions on the maximum load due to the modes of operation of the power system (technical feasibility generating equipment was not taken into account in the work under consideration).&#x0D; Main results of research: the result of calculation, it is clearly seen that when taking into account the thermal conditions of overhead power lines, the allowable active power flows differ by 1626 % from the values determined only when taking into account the ambient temperature.

Ways to improve the efficiency of methods and means of counteracting unauthorized speech recording and their comparative analysis

The features of using ultrasonic, electromagnetic and acoustic methods to counteract unauthorized recording of speech on sound recording devices are considered. The advantages and unused possibilities of the methods are noted. Ways to increase the effectiveness of the ultrasonic method of counteraction consist in using the two-frequency ultrasonic method, in positioning the device for emitting ultrasonic vibrations no more than two meters from the target, in using high-intensity ultrasonic vibrations, in using the ultrasonic method together with the acoustic method, and others. Ways to increase the effectiveness of the electromagnetic method consist in using amplitude-pulse modulation of the interference signal, narrowly directed antennas, a device with a maximum allowable power, and others; Ways to increase the effectiveness of the acoustic method consist in creating speech-like interference from the speech of the interlocutor (synchronized with speech pauses), reducing the distance between the source of interference radiation and the source of speech in relation to the distance between the interlocutors due to organizational protection measures. (adapted acoustic method).&#x0D; The most promising is the adapted acoustic method having the greatest potential for guaranteed countermeasures, subject to the requirements for its optimal use.&#x0D; Analyzing the results of the experiment, we conclude that the adapted acoustic method is the most effective. The effectiveness of the method confirms the suppression range from 1.8 m to 3.5 m depending on the device, for comparison, in the ultrasonic experiment, one of the indicators was 0.9 m, and in the electromagnetic experiment, even 0 m. The formation of interference through the acoustic channel is higher the described method ensures the universality of the proposed method to the type of device for suppressing unauthorized speech recording, regardless of the underlying method – electromagnetic, ultrasonic or acoustic.

Performance analysis of an SDM-WDM multicore optical fiber link

Analytical evaluation of inter-channel and inter-core coupling induced crosstalk including Amplified Spontaneous Emission (ASE) noise in a single mode 7-core homogeneous multi-core optical fiber (MCF) based Space Division Multiplexed Wavelength Division Multiplexing (SDM-WDM) communication system with distributed Raman amplifier is presented. The Stimulated Raman Scattering (SRS) induced crosstalk impairment including ASE noise and inter-core and inter-channel coupling induced crosstalk at the output of any core with excitation into other core of the MCF is investigated. Signal to Crosstalk plus Noise Ratio (SCNR) is determined at the output of photo detector of the excited core. Finally, Bit Error Rate (BER) performance results are evaluated for different system parameters, viz. WDM channel number, channel spacing, propagation distance, pump power etc. It is noticed that BER deteriorates with SRS induced crosstalk and ASE noise, which is worsened further by the effect of inter-core crosstalk (IC-XT). The maximum acceptable propagation distance for a desired value of BER and other system parameters considering inter-channel crosstalk (Ich-XT), IC-XT including SRS induced crosstalk and ASE noise is also evaluated analytically. For example, to maintain a particular BER (10E-9, say) we need to increase the input signal power from 2.5dBm to 5.5dBm while increasing the WDM channels from 12 to 16 considering only the SRS and ASE noise. On the other hand, we need to increase the input signal power from 5.5dBm to 9.0dBm to increase the WDM channels from 12 to 16 when the IC-XT is added up with the SRS and ASE noise. The maximum allowable pump power considering the collective impact of Ich-XT and IC-XT including SRS and ASE noise is determined for a given value of BER (10E-9). Power penalty versus WDM channel spacing at a given BER value (10E-10), link distance and pump power at different WDM channels is also evaluated and presented.

Factors affecting voltage stability while integrating inverter based renewable energy sources into weak power grids

AbstractWith the emergence of renewable energy sources (RESs), the power grid all over the world is going through a paradigm shift. The inverter based RESs are replacing the conventional rotating synchronous generators and this trend is expected to continue in coming years. Consequently, the grid strength is decreasing, which can pose significant challenges on the grid stability, especially during integration of IRESs. This paper presents a thorough analysis on the integration challenges of IRESs in weak grids. The paper also presents a comprehensive investigation on the impacts of factors, such as available fault level at the point of interconnection (POI), feeder length and grid nature on the POI voltage, and maximum allowable power injection by IRES. This is followed by maximum allowable IRES power injection sensitivity analysis to quantify the impacts of the aforementioned factors. The paper concludes with a thorough case study on the IEEE 39‐bus test system to numerically show the impact of diminishing grid strength on the integration of IRESs.

Large Signal Analysis on Variations of the Hybridized Dickson Switched-Capacitor Converter

Dickson-type dc–dc converters have gained renewed interest in recent years due to their best-in-class volt-amp switch utilization. In addition, “hybrid” switched-capacitor (HSC) structures increase passive component utilization while avoiding the slow-switching limit (SSL), and yet, most HSC work to date has done little to assess large signal voltage ripple behavior and subsequent passive utilization limits. This work contributes a comprehensive review of contemporary Dickson-type HSC converters before introducing eight fundamental reduced HSC Dickson structures, including three that are proposed here. Analysis allowing characterization of large signal operating points, capacitor sizing regimes, switching schemes, and maximum allowable power throughput is introduced. The analysis for “split-phase” switching is also presented in detail, without making small ripple approximations. Furthermore, an expression for large ripple flying capacitor energy density utilization is derived, assisting with optimal topology selection and revealing that split-phase operation may be preferable for conversion ratios greater than 6:1. All analysis is verified in simulation, with an additional discrete hardware prototype further validating a complex case of resonant split-phase timing. The analytical results of 17 distinct Dickson variations are recorded, assisting with topology selection and design.

TokenSmart: Distributed, Scalable Power Management in the Many-core Era

Centralized power management control systems are hitting a scalability limit. In particular, enforcing a power cap in a many-core system in a performance-friendly manner is quite challenging. Today’s on-chip controller reduces the clock speed of compute domains in response to local or global power limit alerts. However, this is opaque to the operating system (OS), which continues to request higher clock frequency based on the workload characteristics acting against the centralized on-chip controller. To address these issues, we introduce TokenSmart, which implements a set of scalable distributed frequency control heuristics within the OS, using a novel token-based mechanism. The number of system-allocated power tokens represents the maximum allowable power consumption; and the OS governor orchestrates a token-passing (or sharing) algorithm between the compute engines. Token allocation count increase (decrease) corresponds to a increase (decrease) of clock frequency. The compute units are connected in a ring-topology allowing minimal meta-data to be passed along with the token value for regulating power budget. We explore different heuristics to assign tokens smartly across the units. This results in efficient power regulation and sustenance of turbo frequencies over a longer duration. Our proposed methodology can be implemented in hardware with multiple on-chip controllers, or in software where each set of cores acts as a compute unit. The methodology is currently implemented within the Linux kernel of a real IBM POWER9 many-core system and experimentally verified on different real world workloads such as Redis, Cassandra, PostgreSQL along with a micro-benchmark such as rt-app. Our experiments indicate the increase in throughput for all the workloads along with the benefit of power savings. For instance, results show a considerable boost of about 4% in throughput of both the PostgreSQL and Redis benchmark with a substantial savings in power consumption (18% and 37%, respectively). If the approach is implemented in hardware, then our experimental analysis speculates the throughput to increase up to 14% in PostgreSQL benchmark.

Behaviors of photovoltaic cells illuminated by a laser of different operation modes.

The ultimate capability of light-electricity conversion of a laser with different operation modes in a typical photovoltaic (PV) cell was investigated for the technologic concept of laser power transmission (LPT). The quasi-linear correlation between the maximum allowable laser power density and the pulsed laser power percentage (PPP) of the combined dual lasers was found experimentally on a tri-junction GaAs PV cell. At the same time, the patterns of thermomechanical damage in the PV cells were characterized. The physical mechanism on the difference in the light-electricity conversion ability for a multi-pulse (MP) laser and a continuous wave (CW) laser was revealed by the coupled model on thermal diffusion and the carrier transport.

Seismic risk analysis of electrical substations based on the network analysis method

AbstractElectrical substations are critical elements of a power grid, enabling the transmission and distribution of electric power from power generators to the end‐users. Experiences from previous earthquakes have shown that electrical substations can be damaged due to ground shaking, reducing their functionality and potentially preventing the generated electric power from reaching end‐users. To assess the seismic vulnerability of a substation, a modular quantitative assessment method is proposed. In this method, the relation between the functionality state of a substation and the damage state of its components was established through the connection matrix technique. A substation is viewed as a network system, whose topology is defined by the connections among various pieces of electrical equipment (i.e., the components), represented in the connection matrix. The maximum allowable power transmission capacity of the substation after an earthquake is adopted as the system functionality metric, which is jointly determined by the power input, transform, and output capacity of the substation. The seismic vulnerability of an electrical substation is quantified by probabilistically calculating its postearthquake functionality when exposed to various earthquake intensities using Monte Carlo sampling. Finally, the risk of substation functionality loss is quantified by integrating the seismic hazard curve with the seismic vulnerability model of the substation. Two realistic case studies on a distribution substation and a transmission substation, with the same equipment configuration but different power delivery paths, were performed using the proposed method. Furthermore, a sensitivity analysis regarding the equipment fragility parameters is conducted, providing a risk‐informed basis for improving the seismic performance of the substation system.

Increasing the transmission capacity an inhomogeneous electrical network by regulating the equalizing EMF

THE PURPOSE. Consideration of issues related to the study of ways to increase the capacity of the electrical network, characterized by the maximum transmitted power between the nodes of the electrical network. Switching in the electrical network and power imbalance in nodes during transmission of electricity are reasons of overloads and blackouts. To prevent overloads, the transmission volumes are reduced. It is the reason for a decrease in the reliability of power supply to consumers, the efficiency of using energy resources and disconnection of systems. In practice, the traditional methods of reducing network congestion are generation regulation, changing the network topology, and, if they are not enough, disconnecting consumers from the power grid.METHODS. Solving the problem, a computer model was used, created in the RastrWin3. This study transmission capacity of the electrical network with the taking influence equalizing EMF between the nodes of the power grid.RESULTS. The article describes the relevance problems, it is shown that the regulation of the equalizing EMF allows you to change the value of the maximum allowable power transmitted between the nodes of the electrical network. CONCLUSION. The results of the study can be used in the practice of dispatch control to solve problems of improving the reliability, planning and operating the power system in real time. The efficiency of the proposed algorithm is tested experimentally.

Effects of the micro-post array on the maximum allowable input power for a micro pulsating heat pipe

This study is performed to experimentally investigate the effects of the micro-post array (MPA) and its arrangements on the maximum allowable input power for a micro pulsating heat pipe (MPHP). The maximum allowable input powers for MPHPs with the MPAs in three different arrangements are measured and compared to that for the conventional MPHP (without the MPA). To do this, ten-turn MPHPs with and without the MPA are fabricated using MEMS techniques. The overall dimensions of the MPHPs are 53 × 38 × 1.5 mm3, and the width and the height of the meandering rectangular channels are 1500 µm and 660 µm, respectively. The MPA in each case is placed on the bottom surfaces of the channels. The dimensions of the MPA are analytically determined in such a way to maximize the rate of the capillarity-induced flow by solving the Brinkman-extended Darcy's equation: the diameter, the pitch and the height are determined to be 33 µm, 97 µm, and 80 µm, respectively. The MPA is placed in three different arrangements: in alternating pairs of channels, in alternating channels, or in all channels. Ethanol is selected as the working fluid. The experiments are conducted in a horizontal orientation, and the flow is visualized with high-speed photography. The experimental results show that the MPA can have either a favorable or an adverse effect depending on its arrangement. If the MPA is placed in alternating channels, the maximum allowable input power is enhanced by 44%, compared to that for the conventional MPHP, and if it is placed in alternating pairs of channels, the maximum allowable input power is enhanced by 36%. On the other hand, the MPHP does not operate at all at any input power if the MPA is placed in all channels. Therefore, in case of the MPHP where a vapor plug oscillates in its own channel, the MPA should be placed in alternating pairs of channels or in alternating channels to enhance the maximum allowable input power for an MPHP.