Identification Method for Users-Transformer Relationship in Station Area Based on Local Selective Combination in Parallel Outlier Ensembles Algorithm

In the power distribution system,the missing or incorrect file of users-transformer relationship(UTR)in lowvoltage station area(LVSA)will affect the leanmanagement of the LVSA,and the operation andmaintenance of the distribution network.To effectively improve the lean management of LVSA,the paper proposes an identification method for the UTR based on Local Selective Combination in ParallelOutlier Ensembles algorithm(LSCP).Firstly,the voltage data is reconstructed based on the information entropy to highlight the differences in between.Then,the LSCP algorithmcombines four base outlier detection algorithms,namely Isolation Forest(I-Forest),One-Class Support VectorMachine(OC-SVM),Copula-Based Outlier Detection(COPOD)and Local Outlier Factor(LOF),to construct the identification model of UTR.This model can accurately detect users’differences in voltage data,and identify users with wrong UTR.Meanwhile,the key input parameter of the LSCP algorithm is determined automatically through the line loss rate,and the influence of artificial settings on recognition accuracy can be reduced.Finally,thismethod is verified in the actual LVSA where the recall and precision rates are 100%compared with othermethods.Furthermore,the applicability to the LVSAs with difficult data acquisition and the voltage data error in transmission are analyzed.The proposed method adopts the ensemble learning framework and does not need to set the detection threshold manually.And it is applicable to the LVSAs with difficult data acquisition and high voltage similarity,which improves the stability and accuracy of UTR identification in LVSA.

Energy Loss Analysis of Distributed Rooftop Photovoltaics in Industrial Parks

The analysis of the loss of distributed photovoltaic power generation systems involves the interests of energy users,energy-saving service companies,and power grid companies,so it has always been the focus of the industry and society in some manner or another.However,the related analysis for an actual case that considers different cooperative corporations’benefits is lacking in the presently available literature.This paper takes the distributed rooftop photovoltaic power generation project in an industrial park as the object,studies the analysis and calculation methods of line loss and transformer loss,analyzes the change of transformer loss under different temperatures and different load rates,and compares the data and trend of electricity consumption and power generation in industrial parks before and after the photovoltaic operation.This paper explores and practices the analysis method of the operating loss of distributed photovoltaic power generation and provides an essential reference for the benefit analysis and investment cost estimation of distributed photovoltaic power generation systems in industrial parks.The analyzed results reveal that the change loss is stable after the photovoltaic is connected,and there is no additional transformer loss.And before and after the photovoltaic system installation,there was no significant change in the total monthly data difference between the total meter and the sub-meter.

Investigating the Effects of the Driving Cycle and Penetration of Electric Vehicles on Technical and Environmental Characteristics of the Hybrid Energy System Considering Uncertainties

Electric vehicles(EVs)have received special consideration from modern society over the past several years.Although EVs are a fine example of environmentally friendly technology and have many advantages,they relatively increase the electricity demand upon a power grid as well.Therefore,their negative impact on busvoltage and line losses should be analyzed.In this study,the effect of EV loads and their penetration on bus voltage and line losses of an IEEE-33 bussystem has been examined via two scenarios.It is important to mention that the effect of EVs on the rate of air pollution,produced by fossil fuel electricity generators,has been investigated throughout the study.Also,the key role of demand response programs in the reduction of EVs’negative effects on the grid has also been discussed in the last scenario.Generally,the simulation of this paper provides a novel and wider perspective on EVs and their effect on grids and environmental pollution.

On the central symmetry of the circumstellar envelope of RS Cnc

We present a phenomenological study of CO（1-0） and CO（2-1） emission from the circumstellar envelope （CSE） of the Asymptotic Giant Branch （AGB） star RS Cnc. It reveals departures from central symmetry that turn out to be efficient tools for the exploration of some of the properties of the CSE. We use a wind model including a bipolar flow with a typical wind velocity of ～8 km s^-1 that decreases to ～2 km s^-1 near the equator. This wind model is used to describe Doppler velocity spectral maps obtained by merging data collected at the IRAM Plateau de Bure Interferometer and Pico Veleta single dish radio telescope. Parameters describing the wind morphology and kinematics are obtained, together with the radial dependence of the gas temperature in the domain of the CSE probed by the CO observations. Significant north-south central asymmetries are revealed by the analysis, which we quantify using a simple phenomenological description. The origin of such asymmetries is unclear.

Security-constrained line loss minimization in distribution systems with high penetration of renewable energy using UPFC

Focused on the challenges raised by the largescale integration of renewable energy resources and the urgent goal of energy saving,a novel control scheme for the unified power flow controller(UPFC)series converter is proposed to achieve line loss reduction and security enhancement in distribution systems with a high penetration of renewable energy.Firstly,the line loss minimum conditions of a general distribution system with loop configurations are deduced.Secondly,security constraints including the permissible voltage range,the line loading limits and the UPFC ratings are considered.System security enhancement with the least increase in line loss is tackled by solving a much reduced optimal power flow(OPF)problem.The computational task of the OPF problem is reduced by deducing the security-constrained line loss minimum conditions and removing the equality constraints.Thirdly,a hybrid control scheme is proposed.Line loss minimization is achieved through a dynamic controller,while an OPF calculator is integrated to generate corrective action for the dynamic controller when the security constraints are violated.The validity of the proposed control strategies is verified in a modified IEEE 33 bus test system.

Optimal Su-Do-Ku based interconnection scheme for increased power output from PV array under partial shading conditions

Partial shading is a common phenomenon in PV arrays. They drastically reduce the power output because of mismatch losses, which are reliant on the shape of the shade as well as the locations of shaded panels in the array. The power output can be improved by distributing the shade over various rows to maximize the current entering the node. A Su-Do-Ku configuration can be used to rearrange the physical locations of the PV modules in a total cross tied PV array with the electrical connections left unchanged. However, this arrangement increases the length of the wire required to interconnect the panels thus increasing the line losses. In this paper, an improved Su-Do-Ku arrangement that reduces the length of the wire required for the connection is proposed. The system is designed and simulated in a Matlab/Simulink environment for various shading patterns and the efficacies of various arrangements are compared. The results prove that the power output is higher in the proposed improved Su-Do- Ku reconfiguration technique compared to the earlier proposed Su-Do-Ku technique.

Impact of the penetration of distributed generation on optimal reactive power dispatch

Optimal reactive power dispatch(ORPD)is a complex and non-linear problem,and is one of the sub-problems of optimal power flow(OPF)in a power system.ORPD is formulated as a single-objective problem to minimize the active power loss in a transmission system.In this work,power from distributed generation(DG)is integrated into a conventional power system and the ORPD problem is solved to minimize transmission line power loss.It proves that the application of DG not only contributes to power loss minimization and improvement of system stability but also reduces energy consumption from the conventional sources.A recently proposed meta-heuristic algorithm known as the JAYA algorithm is applied to the standard IEEE 14,30,57 and 118 bus systems to solve the newly developed ORPD problem with the incorporation of DG.The simulation results prove the superiority of the JAYA algorithm over others.The respective optimal values of DG power that should be injected into the four IEEE test systems to obtain the minimum transmission line power losses are also provided.