Research On Operation Status Of Distribution Network Equipment And Its Micro-meteorological Monitoring And Early Warning System

With the upgrading of China's gird network,power grid is constantly expanding to operating in an enlarged area with different local micro-meteorological environments.With a rising concern over the damages of the distribution network by extreme weather conditions induced by local terrain environments,it is urgent to establish a management system that can monitor the micro-meteorological conditions for distribution network.By investigating the current situation of a distribution network in a county in Yunnan Province as an example,in this thesis the author analyzes and finds the following problems:(1)The county located in a southwestern mountainous area experiences a complex climate with variable weather characterized by frequent rains that would result into geological disasters such as debris flows,and the disasters pose a great threat to the safe operation of the distribution network;(2)With traditional periodic onsite inspections of the facilities in a dispersed area by limited manpower,there is a lack of fast and accurate monitoring over the facilities for the distribution network,and this causes a great waste of power resource when facility problems could not be resolved timely.To address these problems,this study has been conducted by developing a monitoring system that is suiTab.to the special meteorological conditions in the county areas and able to monitor local environments for distribution network facilities and the operation status of the facilities.The field inspection of operation environment and operation status of the facilities shows effectiveness of the system.The system developed has the potential to improve the quality of power supply and reduce the incidence of distribution network accidents.The contents of this thesis are as follows:1.Overall system design.The system has been designed for micro-meteorological conditions according to the requirements by relevant departments and by comprehensively consider the local meteorological conditions.The detailed steps for designing the systems are mainly the followings:(i)analysis of the meteorological factors that affect the distribution system;(ii)based on the analysis to further analyze sensor technologies and parameters required for data collection;(iii)feasibility comparison and analysis of data transmission and grouping network technologies;(iv)demonstration and discussion of the relevant parameters of the database in order to determine the overall design including embedded technology,communication technology and database application.2.System design for monitoring the indoor and outdoor environments for power distribution room.To meet the requirement for allowing mobile measurement,the outdoor environment monitoring system has been designed by installing the entire collection of devices on a specially designed trolley.The hardware on the trolley includes: wind speed and direction sensor,rainfall sensor,atmospheric pressure sensor,temperature and humidity sensor,light sensor,the main control board STM32,solar panels,solar cells and power supply and its transformer module,in addition to GPRS transmission module.The Indoor monitoring system designed to detect the operating status of power facilities include major hardware such as power supplies and transformer modules,multi-function meters,RFID readers and tags,power frequency detectors,proximity switches,temperature and humidity sensors,etc.,where the special functions of positioning of RFID and proximity switches locate and guard important equipment to avoid theft.3.The overall design of the database supervision center.The database has been programed in C# language in Visual Studio 2010 database development environment.The supervision center consists of three major modules,i.e.customer monitoring terminal,server and database,to complete the storage,display and reading of data,and to provide data for the prediction algorithm.4.Investigation on predicting relative humidity using GA-BP algorithm.As high indoor humidity level affects the insulation and reliability of the power distribution equipment,predicting changes of humidity in short-term according to historical data is an effective approach to help to improve the stability of distribution system.Using MATLAB program with inclusion of GA-BP algorithm,a neural network is built to simulate and predict the humidity level.The neural network can increase the predictability of the relative humidity in the distribution room and help to improve the efficiency in maintenance of electrical equipment.Consequently,the neural network provides technological support for safe and sTab.operation of the power distribution network.5.System debugging.System debugging is performed by joint debugging of all modules of the indoor and outdoor systems.The tests on system data collection,data transmission,data storage and display,and counting the packet loss rate during the transmission process have been conducted at the high-voltage equipment laboratory in Southwest University and at the county power supply bureau in Yunnan province.The results show a low packet loss rate of 1.01%,reliable system communication,and effective functioning of each module.Therefore,it is found the system could be used for data collection and transmission to assist the power supply management department in achieving the purpose of intelligent monitoring of the power distribution network.