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Impact Assessment Of Large-scale PV Access On Distribution Network

Posted on:2020-09-19Degree:MasterType:Thesis
Country:ChinaCandidate:C ZhangFull Text:PDF
GTID:2392330578466738Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
Distributed PV power generation connected to distribution network brings clean energy to China's power grid,but also brings many problems.Due to its own characteristics of dispersion,intermittence and randomness,it will bring certain impact on the power quality of the power grid.With the large-scale connection of distributed PV,it is bound to aggravate the impact on the power grid.Therefore,it is necessary to analyze the impact of large-scale distributed PV access to distribution network on power quality and reasonably evaluate the carrying capacity of distribution network for large-scale distributed PV.Firstly,this paper analyzes the working principle of PV cells and builds a PV cell simulation model.Aiming at the fact that the output power of PV panels is greatly affected by illumination intensity and temperature factors,the maximum power of PV panels is tracked by using disturbance observation method to improve the output efficiency of PV cells.According to the influence of irradiation intensity and temperature on PV output,the characteristics of distributed PV P-U and I-U output under the same illumination intensity,different temperature,different illumination intensity and the same temperature were analyzed,and the characteristics curve of distributed PV output was obtained.Secondly,the impact of large-scale distributed PV access on the power quality of rural distribution network is analyzed.Based on the daily output curve of PV and daily load curve of residents in a rural area of Chaoyang City,Liaoning Province,the voltage and harmonic problems caused by distributed PV connection to rural power grid in different weather and different times are analyzed,and the influence of large-scale distributed PV on the voltage and harmonic of rural power grid under different real-time penetration rates is studied.Aiming at the serious problem of voltage exceeding of rural power grid after large-scale PV connection,a voltage regulation control strategy with reactors installed at the outlet of transformer is proposed to effectively improve the voltage exceeding caused by large-scale PV connection.In view of the serious harmonic pollution of rural power grid caused by excessive voltage harmonic content and distortion rate after large-scale PV access,this paper puts forward effective measures to suppress harmonic.Finally,in view of the adverse effects of large-scale PV power supply connected to the rural distribution network,the basic principles of Newton Raphson method,Jacobian matrix and sensitivity used in power flow simulation are analyzed,taking voltage as the main factor restricting the acceptance rate of large-scale PV,and based on the voltage sensitivity analysis method,the sensitivity point after PV grid connection is determined according to the maximum sensitivity coefficient in the active voltage sensitivity matrix after large-scale PV grid connection,so that the maximum PV carrying capacity and acceptance rate in rural areascan be obtained when the sensitivity point voltage is the maximum limit.In order to solve the problem that the voltage at the sensitive point exceeds the limit,the voltage at the sensitive point is improved by adding a reactor at the outlet of the transformer,and the PV carrying capacity of the rural distribution network before and after the voltage regulation is added is effectively evaluated through simulation analysis of two typical rural distribution network examples.
Keywords/Search Tags:Large-scale distributed PV, Distribution network, Power quality, Voltage sensitivity, Carrying capacity
PDF Full Text Request
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