Research On Voltage Quality Of Small Hydropower Distribution Power System

With the development of the economy and the increase in energy demand,clean energy has begun to promote and gradually replace fossil fuels with high energy consumption and high pollution in recent years.Small hydropower,as a kind of distributed power supply,can not only ease energy shortage problems,to a certain extent,also promote local economic development.Small hydropower is generally built in remote mountainous areas,providing corresponding guarantees for local residents' electricity use and bringing certain economic benefits to themselves.However,the small-scale hydropower stations have lower voltage levels and most of them are runoff hydropower stations.Poor regulation ability and strong seasonality often result in a series of problems such as large voltage fluctuations in the distribution network,inconsistent system currents,and voltage overruns along the line,which cannot provide local residents with safe and stable power quality,and serious threatening the normal operation of electrical equipment.In addition,SHP generally does not fall under the jurisdiction of the local power supply company.The power grid dispatch department cannot monitor the operation of SHP,making the original complex distribution network route more difficult to analyze.Therefore,it is very important to analyze the distribution lines of small hydropower distribution networks and focus on the power quality and distribution network reliability of the lines.This paper mainly analyzes the voltage quality of small-scale hydropower distribution networks.Firstly,it begins with the equivalent structure of small hydropower in the distribution network.It introduces several connection modes and equivalent models of small hydropower in the distribution network.The small hydropower access to the distribution network will have a certain impact on the system's power distribution,network loss size,reactive power voltage and relay protection measures.The impact of small hydropower on the distribution network is analyzed by establishing the string structure of small hydropower,namely the "string lantern" model.The power system comprehensive analysis softwarePSASP is used to simulate the operation of the model,and then the main problems of the small hydropower grid-connected operation are summarized.Analyze the reasons for the insufficiency of reactive power of SHP and provide corresponding solutions and suggestions from the technical level and SHP management.In view of the characteristics of large voltage fluctuations in the distribution network and strong seasonality of small hydropower stations,several voltage regulation methods are introduced and applied to high voltage in high water period and low voltage in low water period to verify the feasibility and applicability of the method.Finally,the voltage optimization of the 10 kV farmland line in Ningqiang area of Shaanxi Province was analyzed,a comprehensive consideration is given to the cost investment of the voltage regulator,and the most ideal scheme is selected to solve the line voltage problem through the comparison and analysis of the effect of voltage regulation.The simulation results show that the proposed scheme can solve the problem of voltage overrun in agricultural lines,and the proposed method has wide application in the voltage optimization of such distribution networks with small hydropower,and provides reference for the future optimization and transformation of the farmland line.It will play a guiding role in the voltage optimization of other distribution networks with small hydropower.