Study And Development Of The Information System Of WAMS Light

The Wide-Area Measurement System (WAMS) of the Phasor Measurement Unit (PMU) has been applied in the worldwide power system and has played a major role in security-monitoring, stability-analyzing and controlling. Based on the traditional PMU, the research group of this paper’s author developed a synchronized Phasor Measurement Units Light (PMU Light) applied in the low-voltage side of the power grid. Moreover, major colleges and universities of the country have been configured with this device, and then the Wide-Area Measurement System Light (WAMS Light) was built. With the PMU Light configured in the country more and more, the datum of high precision and high dengsity provided more and more. What’s more, the online data-processing program and visualize application of WAMS Light cannot carry out the real-time processing and display of the datum efficiently. Therefore, it’s urgent to analyze and process the real-time datum of power grid online, and display the real-time state of the system and results of the online analysis through the intuitive and effective visual methods. In order to realize these functions, a good WAMS Light information system is needed.The main contents of this paper are as follows:(1)A WAMS Light information system is developed, which consists of the data server, application server, Web server, and visual display terminal.etc. These components are interconnected by Ethernet of100M. The methods of reception, storage and display of the original datum measured by PMU Light are introduced. The principles and realization methods of the Socket communication are introduced. The Access database used for the original data storage and the MySQL real-time database used for data storage in real time are developed. The main functions of the application server and the Web server are designed.(2)The design realizes online assessment of frequency security, and explores the characteristics and online identification of frequency instability trajectory. In this paper, quantitative assessment methods of frequency offset proposed by the research group are implemented online. Based on the relationship between the frequency curve and binary table, and the safety margin calculation through the data filtering, an online assessment module of frequency safety is developed and integration. Because the generators tripping under low frequency in the system is the necessary condition of transient frequency instability, generators must be excised before the crash. Thus the convex frequency curve is the necessary condition of frequency instability; we can utilize the features of frequency track curve which is convex or concave to monitor transient frequency stability online. In this paper, the program using the characteristics of frequency trajectory curves to determine the system frequency stability is developed, and the simulation data and the measured data are used to analyze examples.(3)In order to display a large number of real-time datum measured by the system in a more intuitive way, and to make people grasp the real-time running state and trend of power system more clearly and accurately, this paper researches on data visualization methods and develops the visual programs. These methods and programs include server-side concentrating graphs display of the frequency, voltage and phase angle from every measuring point in the country; real-time display of voltage vector diagrams, and records and visual display of accident information. Since the conventional two-dimensional visualization methods are difficult to display multi-dimensional information accurately, the methods of3D visualization are also studied in this paper. Interpolated calculating each pixel by inversing distance interpolation algorithm, drawing3D pictures through the corresponding color mapping table in the Qt,3D visualization can show the trends of the system more intuitively.(4)The traditional visualization platform is limited to the server, so users can’t know the real-time running status of the power grid anytime and anywhere. With the rapid development of wireless network and intelligent mobile terminal, expanding of the data access is needed to study. This paper develops a visualization program that supports the mobile. This program, based on the Android system, can read real-time WAMS Light data in the database through the network, process the data, and display results through the frequency, voltage and phase angle curves, thus remote mobile access of WAMS Light is realized.