Study On The Solutions Of Low-Voltage Issue In Distribution Network

Currently,the problem of low voltage in distribution network is still prominent now,and there also be a great impact on the reliability and economic operation of power grid,some even affect people’s normal life and work.So the solutions of low-voltage issue in distribution network has important practical significance and economic value,it is also imperative to study the solutions of low-voltage issue in distribution network.This thesis proposes a complete,systematic and process solution of low voltage problem in distribution network based on the real-time monitoring of low voltage in distribution network.First at all,this thesis briefly describes the low-voltage causes in distribution network in the management level and technical level;in view of the rapid growth of electricity load and distribution network development is lagging behind,and the weak structure of the grid and the superior power point support,analyzing the corresponding technical governance measures;discussing the engineering measures that the three governance objects of substation,medium voltage distribution line and distribution area can take.Simultaneously,this thesis uses PSCAD/EMTDC to build the power supply network model according to a distribution area and upper 10 kV line,then simulates and verifying the feasibility and effectiveness of the proposed technical measures.Secondly,this thesis presents a voltage overrun monitoring system in distribution network,which has specific function,high precision,low cost and is user-friendly.This instrument can monitor low-voltage problem of single-phase or three-phase in real time by setting the upper and lower limit of voltage,also can sent the voltage overrun data to the backhaul data center through wireless communication.This thesis also shows the design about hardware of the voltage limit monitor for this system,including a main controller using AT85C2051,a data storage module,a data acquisition unit,a clock module,a communication unit and a power supply module;and introducing the flow of the microcontroller program;and clarifying the implementation steps of a compression methods about data transmission protocol for this system.Finally,this thesis presents a set of comprehensive solution for low-voltage problem in distribution network: analyzing the low generation about the high voltage side and the low voltage side of the distribution transformer in turn,and choosing the governance measures corresponding to different causes,then establishing the best scheme for solving low-voltage issue and evaluating the effect of this scheme.This thesis also shows the methods on evaluating the effectiveness of the scheme for solving low-voltage issue: establishing the assessment index system about the effectiveness of this scheme,and using fuzzy comprehensive evaluation methods to score each bottom indexes,then combining with the weights of each indexes setted by AHP to calculate the score about the effectiveness of this scheme.