On-line Monitoring System Of Power Quality In Jiansheng Thermal Power Plant

Jiansheng thermal power Plant is located in Suihua city,Heilongjiang Province,founded in 2003.Due to the long operation time and frequent replacement of old and new equipment,the power grid operation in the plant is very unstable.During this period,there was no complete power quality monitoring system in Jiansheng thermal power plant,and the old fixed-point regular power quality monitoring method could not meet the needs of the development of the power grid,and it could not make specific and accurate evaluation on the influencing factors of power quality in the power grid.Based on the above reasons,a large number of materials and research data were consulted,and a practical online power quality monitoring system was designed for the thermal power plant,so as to complete the real-time monitoring of every link in the internal system of the whole thermal power plant.The first part of the paper analyzes the development of power quality monitoring,and power index detection methods and monitoring equipment for research and analysis.According to the national and industry standards of each index of power quality,the testing methods of each index are studied and compared,and the testing methods of each index are finally determined.Then the hardware and software of the monitoring system are designed.Firstly,the hardware is divided into five units: Analog Signal Sampling Unit,digital signal sampling unit,Processing Unit,control unit and Communication Unit,after the voltage and current signals to be detected are converted into digital signals by analog and digital sampling units,through the communication unit to the processing and control unit to complete the data transmission,calculation,storage design process.Secondly,the software of Windows 7 as the operating system,the use of C language for software design.The basic operation flow of the software is designed and determined,and the design process of the software communication module and the index calculation module is introduced in detail.At the end of this paper,the system is verified by experiments,and the error of measurement data is up to the national and industrial standards.The system can also provide thermal power plant power quality indicators data collection,storage,complete power quality data 24-hour non-gap monitoring;On the potential safety hazards play a preventive role in advance.After the system was put into use,the power quality of the power plant has been significantly improved.For sudden equipment faults,line faults,fire accidents,etc.in the power grid,it can give an accident alarm in the first time,shorten the time of line patrol and fault point identification one by one,so as to minimize the accident loss as far as possible,and the collected data truly reflect the current situation of the power grid and equipment.The power quality network supervision capacity of the whole power grid in the plant has been further improved,the loss of the power grid has been gradually reduced,and the frequency of shutdown and accident has also been greatly reduced.It provides a strong guarantee for the safe and stable operation of power grid.