Research On Power Quality Analysis And Evaluation Method Of Distributed New Energy

With the construction of a strong smart grid to speed up,the contemporary power grid in many aspects have a profound changes,the power quality disturbances of the grid begin to show new characteristics.The current distribution of new energy power generation is developing rapidly,and put forward new challenges to the grid operation.Large-scale new energy power generation needs long-distance transmission to the load center,brought the problem of the system frequency and voltage because of stochastic volatility and intermittency of the powerAiming at the above problems,this paper has carried out research on the analysis and evaluation methods of distributed new energy.Firstly,a power quality analysis method based on the characteristic harmonic model is proposed.It is divided into five steps:data preprocessing,global analysis,classification,working condition analysis and characteristic harmonic modeling.Complete the data classification based on the overall analysis of dataset,analyzed the different working conditions to master the impact of distributed photovoltaic grid-connected,and then combined with the working condition analysis,to complete the characteristic harmonic density model,finally,complete the method validation with the measured data.Then,a power quality evaluation method based on the connection degree model is proposed.Introduce the concept of connection degree to solve the uncertainty of power quality evaluation index,establishes the link degree model of power quality evaluation,meanwhile,in order to solve the problem of the uncertainty coefficient of the degree of difference,establishes the rank stability analysis model.Finally,complete the power quality rating evaluation with four sets of measured data and analysis of stability of the power quality order.The results of method validation show that the proposed method of power quality analysis and evaluation for distributed new energy is based on practical and feasible which can realize the quantization of the characteristic harmonics,the evaluation of the power quality level and the stability analysis of the order.The results of this study can evaluate the power quality of distributed new energy generation before it is connected.The results of this study can evaluate the power quality of the distributed new energy generation before the access,put forward the corresponding preventive measures,and reduce the impact of distributed new energy grid-connected.It adapts to the current demand of the electric network,has broad applicability and application prospect.