RL and AHP-Based Multi-Timescale Multi-Clock Source Time Synchronization for Distribution Power Internet of Things

Time synchronization(TS)is crucial for ensuring the secure and reliable functioning of the distribution power Internet of Things(IoT).Multi-clock source time synchronization(MTS)has significant advantages of high reliability and accuracy but still faces challenges such as optimization of the multi-clock source selection and the clock source weight calculation at different timescales,and the coupling of synchronization latency jitter and pulse phase difference.In this paper,the multi-timescale MTS model is conducted,and the reinforcement learning(RL)and analytic hierarchy process(AHP)-based multi-timescale MTS algorithm is designed to improve the weighted summation of synchronization latency jitter standard deviation and average pulse phase difference.Specifically,the multi-clock source selection is optimized based on Softmax in the large timescale,and the clock source weight calculation is optimized based on lower confidence bound-assisted AHP in the small timescale.Simulation shows that the proposed algorithm can effectively reduce time synchronization delay standard deviation and average pulse phase difference.

Experimental Study on the Performance of ORC System Based on Ultra-Low Temperature Heat Sources

This paper discussed the experimental results of the performance of an organic Rankine cycle(ORC)system with an ultra-low temperature heat source.The low boiling point working medium R134a was adopted in the system.The simulated heat source temperature(SHST)in this work was set from 39.51°C to 48.60°C by the simulated heat source module.The influence of load percentage of simulated heat source(LPSHS)between 50%and 70%,the rotary valve opening(RVO)between 20%and 100%,the resistive load between 36Ωand 180Ωor the no-load of the generator,as well as the autumn and winter ambient temperature on the system performance were studied.The results showed that the stability of the system was promoted when the generator had a resistive load.The power generation(PG)and generator speed(GS)of the system in autumn were better than in winter,but the expander pressure ratio(EPR)was lower than in winter.Keep RVO unchanged,the SHST,the mass flow rate(MFR)of the working medium,GS,and the PG of the system increased with the increasing of LPSHS for different generator resistance load values.When the RVO was 60%,LPSHS was 70%,the SHST was 44.15°C and the resistive load was 72Ω,the highest PG reached 15.11 W.Finally,a simulation formula was obtained for LPSHS,resistance load,and PG,and its correlation coefficient was between 0.9818 and 0.9901.The formula can accurately predict the PG.The experimental results showed that the standard deviation between the experimental and simulated values was below 0.0792,and the relative error was within±5%.

ESTIMATION OF THE NUMBER OF CORRELATED SOURCES WITH COMMON FREQUENCIES BASED ON POWER SPECTRAL DENSITY

Blind source separation and estimation of the number of sources usually demand that the number of sensors should be greater than or equal to that of the sources, which, however, is very difficult to satisfy for the complex systems. A new estimating method based on power spectral density （PSD） is presented. When the relation between the number of sensors and that of sources is unknown, the PSD matrix is first obtained by the ratio of PSD of the observation signals, and then the bound of the number of correlated sources with common frequencies can be estimated by comparing every column vector of PSD matrix. The effectiveness of the proposed method is verified by theoretical analysis and experiments, and the influence of noise on the estimation of number of source is simulated.

Method for measuring the low-frequency sound power from a complex sound source based on sound-field correction in a non-anechoic tank

Similar to air reverberation chambers, non-anechoic water tanks are important acoustic measurement devices that can be used to measure the sound power radiated from complex underwater sound sources using diffusion field theory. However,the problem of the poor applicability of low-frequency measurements in these tanks has not yet been solved. Therefore,we propose a low-frequency acoustic measurement method based on sound-field correction(SFC) in an enclosed space that effectively solves the problem of measuring the sound power from complex sound sources below the Schroeder cutoff frequency in a non-anechoic tank. Using normal mode theory, the transfer relationship between the mean-square sound pressure in an underwater enclosed space and the free-field sound power of the sound source is established, and this is regarded as a correction term for the sound field between this enclosed space and the free field. This correction term can be obtained based on previous measurements of a known sound source. This term can then be used to correct the mean-square sound pressure excited by any sound source to be tested in this enclosed space and equivalently obtain its free-field sound power. Experiments were carried out in a non-anechoic water tank(9.0 m × 3.1 m × 1.7 m) to confirm the validity of the SFC method. Through measurements with a spherical sound source(whose free-field radiation characteristics are known),the correction term of the sound field between this water tank and the free field was obtained. On this basis, the sound power radiated from a cylindrical shell model under the action of mechanical excitation was measured. The measurement results were found to have a maximum deviation of 2.9 d B from the free-field results. These results show that the SFC method has good applicability in the frequency band above the first-order resonant frequency in a non-anechoic tank. This greatly expands the potential low-frequency applications of non-anechoic tanks.

Joint DOA and polarization estimation for unequal power sources based on reconstructed noise subspace

In most literature about joint direction of arrival（DOA） and polarization estimation, the case that sources possess different power levels is seldom discussed. However, this case exists widely in practical applications, especially in passive radar systems. In this paper, we propose a joint DOA and polarization estimation method for unequal power sources based on the reconstructed noise subspace. The invariance property of noise subspace（IPNS） to power of sources has been proved an effective method to estimate DOA of unequal power sources. We develop the IPNS method for joint DOA and polarization estimation based on a dual polarized array. Moreover, we propose an improved IPNS method based on the reconstructed noise subspace, which has higher resolution probability than the IPNS method. It is theoretically proved that the IPNS to power of sources is still valid when the eigenvalues of the noise subspace are changed artificially. Simulation results show that the resolution probability of the proposed method is enhanced compared with the methods based on the IPNS and the polarimetric multiple signal classification（MUSIC） method. Meanwhile, the proposed method has approximately the same estimation accuracy as the IPNS method for the weak source.

Enhancing Renewable Energy Integration:A Gaussian-Bare-Bones Levy Cheetah Optimization Approach to Optimal Power Flow in Electrical Networks

In the contemporary era,the global expansion of electrical grids is propelled by various renewable energy sources(RESs).Efficient integration of stochastic RESs and optimal power flow(OPF)management are critical for network optimization.This study introduces an innovative solution,the Gaussian Bare-Bones Levy Cheetah Optimizer(GBBLCO),addressing OPF challenges in power generation systems with stochastic RESs.The primary objective is to minimize the total operating costs of RESs,considering four functions:overall operating costs,voltage deviation management,emissions reduction,voltage stability index(VSI)and power loss mitigation.Additionally,a carbon tax is included in the objective function to reduce carbon emissions.Thorough scrutiny,using modified IEEE 30-bus and IEEE 118-bus systems,validates GBBLCO’s superior performance in achieving optimal solutions.Simulation results demonstrate GBBLCO’s efficacy in six optimization scenarios:total cost with valve point effects,total cost with emission and carbon tax,total cost with prohibited operating zones,active power loss optimization,voltage deviation optimization and enhancing voltage stability index(VSI).GBBLCO outperforms conventional techniques in each scenario,showcasing rapid convergence and superior solution quality.Notably,GBBLCO navigates complexities introduced by valve point effects,adapts to environmental constraints,optimizes costs while considering prohibited operating zones,minimizes active power losses,and optimizes voltage deviation by enhancing the voltage stability index(VSI)effectively.This research significantly contributes to advancing OPF,emphasizing GBBLCO’s improved global search capabilities and ability to address challenges related to local minima.GBBLCO emerges as a versatile and robust optimization tool for diverse challenges in power systems,offering a promising solution for the evolving needs of renewable energy-integrated power grids.

ANALYSIS OF HYDRAULIC POWER SOURCES DISPOSITION AND ENERGY CONSUMPTION FOR HYDRAULIC DRILL RIG

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Multi-Deployment of Dispersed Power Sources Using RBF Neural Network

Multi-deployment of dispersed power sources became an important need with the rapid increase of the Distributed generation (DG) technology and smart grid applications. This paper proposes a computational tool to assess the optimal DG size and deployment for more than one unit, taking the minimum losses and voltage profile as objective functions. A technique called radial basis function (RBF) neural network has been utilized for such target. The method is only depending on the training process;so it is simple in terms of algorithm and structure and it has fast computational speed and high accuracy;therefore it is flexible and reliable to be tested in different target scenarios. The proposed method is designed to find the best solution of multi- DG sizing and deployment in 33-bus IEEE distribution system and create the suitable topology of the system in the presence of DG. Some important results for DG deployment and discussion are involved to show the effectiveness of our proposed method.

Method for Determination of Optimal Installed Capacity of Renewable Sources of Energy by the Criterion of Minimum Losses of Active Power in Distribution System

New method for determination of optimal placement and value of installed capacity of renewable source of energy (RES) by the criterion of minimum losses of active power, that allows taking into consideration the dependence of RES on natural conditions of region, schedule of energy supply, parameters and configuration of distribution network is suggested in the paper. Results of computations of test scheme confirm the efficiency of the proposed method and its simplicity as compared with the methods considered in literature sources.

Adjusting and Optimizing Structure of Energy Sources for Power Generation of Fujian Province in the 21st Century

The author puts forward the pattern of optimizing the structure of energy sources for generating power in the early stage of the 21st century in Fujian Province; analyzes imper’tant functions on speeding up nuclear power for adjusting the structure of energy sources and heightening economic benefits.and suggests that the first liquefied natural gas combined-cycle power plant will start to build at the end of this century and every effort is made so as to change the recent unreasonable structure of energy source step by step and form the optimized structure of energy sources for generating power, that includes hydropower, thermal power (coal, oil and natural gas), nuclear power, pumpedstorage power, and power from new energy sources. In order to reach the abovementioned significant target, the author discusses the technical and economic measures and the supporting policy to be taken at present and in future.

Optimal Dispatch in Power Systems with Intermittent Power Sources

With the increasing integration of intermittent power sources (IPSs) into the power system, the uncertainty of IPSs requires solution and current dispatch system needs improvement. This paper aims to generate the optimal dispatch plan for day-ahead scheduling and real-time dispatch using the proposed model of characteristic optimal power flow (COPF). The integral time period represented by the median load point and the heavy and light load point with simplicity and accuracy. Simulation case studies on a 30-bus system are presented, which shows that COPF is an effective model to generate the optimal dispatch plan for power systems with high penetration of IPSs.

Large Units, Large Plants -Major Thermal Power Sources

China’s electric power industry as a basic industry, plays an important role in the longterm, sustained and healthy development of the whole national economy. China’s electric power industry attained great achievement in technology and economical results during the past eight years from 1987-1995. The total national installed generating capacity increased from 102.897 GW in 1987 to more than 200 GW in March, 1995.

Power Sources Unlimited负载点变换器

Power Sources Unlimited公司发布其Cincon系列10A和15A非隔离型负载点变换器，采用工业上标准的单列直插(SIP)或表面贴装式封装。SIP10和SMT10系列的输入电压范围是3．0V-5．5VDC，固定输出为1．0VDC到3．3VDC，输出额定电流为10A。这两种版本可通过外部电阻进行电压设定，提供严格调节的0．9VDC到3．63VDC输出，以便一种器件用于多种应用。

Electrochemical power sources:key agents for energy sustainability(Ⅰ)

There is mounting concern over the sustainability of global energy supplies.Among the key drivers are:(ⅰ) global warming,ocean surface acidification and air pollution,which imply the need to control and reduce anthropogenic emissions of greenhouse gases(especially carbon dioxide),nitrogen oxides,sulfur oxides,unburnt hydrocarbons and fine particles;(ⅱ) the low estimated reserves of oil and natural gas;(ⅲ) the need for energy security adapted to each country,such as decreasing the dependence on fossil-fuel imports(in particular,the vulnerability to volatile oil prices) from regions where there is political or economic instability;(ⅳ) the expected growth in world population with the ever-increasing aspiration for an improved standard-of-living for all.Hydrogen is being promoted world-wide as a total panacea for energy problems.As a versatile carrier for storing and transporting energy from any one of a myriad of sources to an electricity generator,it is argued that hydrogen will eventually replace(or at least greatly reduce) the reliance on fossil fuels and thereby also avoid/decrease emissions of carbon dioxide.Not unexpectedly,the building of a ’Hydrogen Economy’ presents great scientific and technological challenges in the production,delivery,storage,conversion and end-use of this energy vector.In addition,there are many policy,regulatory,economic,financial,investment,environmental and safety questions to be addressed.Notwithstanding these obstacles,it is indeed plausible that hydrogen will become increasingly deployed and will compete with traditional systems of energy storage and supply.Future roles for electrochemical power sources ——batteries,supercapacitors,photoelectrochemical cells and fuel cells ——on the pathway to universal energy sustainability in stationary,mobile-power and road transportation applications are examined.

Research Reports on the 12^(th) Five-Year Plan for Electric Power Industry Power Sources

China Electricity Council Abstract:China Electricity Council organized competent authorities across the industry of electric power to work out the "Research Reports on the 12th Five-Year Plan for Electric Power Industry" in nearly one year,which provides a reference for governmental departments to formulate the 12th Five-Year Plan on energy and electric power industry.The magazine will publish the serial reports including power sources,power grids,equipment manufacture,energy and environment,and power economics.This paper presents the part of "power sources," in which the strategies of developing various kinds of power sources are put forward.

Analysis of Development of Nationwide Power Sources in 2007 and Forecast for 2008

Introduction With ever-increasing of power sources, the capabilityof power supply was further enforced in 2007. This met thestrong demand of national economy development. Restruc-turing of power sources was deepening, of which "substi-tuting large power units for small ones" started well, theinstalled capacity of wind power was doubled and obviousresults were achieved in the energy-conservation and pollu-

The 12^(th) Five-Year:Speed Up Structural Adjustment of Power Sources

To the year 2020, China will realize the target of increasing non-fossil generation to 15% of the total energy consumption. Speeding up power sources restructuring comes up as an arduous task during the 12^(th) Five-Year Plan period. In this article, the author outlines the principles of structure adjustment for various kinds of power sources, and points out the issues needing attention during the restructuring.