Research And Practice Of Low Voltage Control In A Distribution Network In Changsha

Low voltage is a common problem in distribution networks,although the state has invested a lot of manpower and material resources to solve the problem in recent years,but it still exists in some areas.The low voltage normalization of comprehensive management has been an important part of the social responsibility of Power Grid Corp.In this paper,a district of Changsha low-voltage distribution network management as an example,the main contents are as follows:Firstly,this paper analyzes the causes of low voltage,and introduces the current research situation in China and abroad.Then it introduces two kinds of technical means to control the low voltage.First,through the installation of reactive power compensation device on the line,the effect of reactive power compensation strategy in improving the voltage is analyzed,then it introduces using feeder automatic voltage regulator(SVR)and dynamic voltage restorer(DVR)respectively to govern low voltage.And it introduces the feeder automatic voltage regulator pressure regulator principle,capacity and installation site selection,as well as the dynamic voltage restorer basic principle.Secondly,Basing on the pre-push and back-generation method,it calculates the trend of distribution network,the automatic voltage regulator is used to control the low voltage,and the theory of the automatic voltage regulator is given.Finally,according to the introduction of reactive control strategy,five cases of low voltage control project in Changsha was selected to be analyzed.For example,the Ding-Yang line's supply radius is long,there is no big branch,line load distribution is balanced.The reason of low voltage is that the reactive power gap is relatively large,and the reactive power compensation device is used to adjust the voltage.For the lack of reactive power,the power supply circuit leads to the low voltage of the end user,for example,the combination of the line voltage regulator and the reactive power compensation device is adopted in the Lake Creek line and the Hutang long pond area.From the aspect of reducing the line loss and the installation of intelligent OLTC comprehensively,it solves the problem of low voltage problem of the line end users.