Study On Design And Implementation Of Overvoltage Online Monitoring System For High Voltage Power Network

Overvoltage is a critical factor of that influence the security of the power system. It is due necessary to do the research on overvoltage so as to guarantee safe operation of power grid. Most of the existing overvoltage monitoring systems adopt divider to get signal. But for the reasons of the divider's self-deficiencies, its application under the higher voltage grade is limited. Aimed to solve this problem, in this paper, the key technologies of overvoltage online monitoring system are researched systematically and a new type of overvoltage monitoring system model machine is developed.This paper presents a method that a special designed voltage transducer is installed at the tap of bushing to get the voltage signal from the power grid. First, it briefly introduces structure of the whole system and its operational principle. And then, structure and parameters setting of the voltage transducer mounted at tap of bushing are presented in detail. The equivalent circuit of bushing capacitive divider system is set up with software Saber. The transducer's output response characteristic can be got by the study on modeling of bushing capacitive divider system. The author analyzes the factors, which influence the transducer's output response characteristic and error characteristic in the paper, and testifies the validity of the model through the experiment in lab. The paper detailedly introduces the primary principles and concretes method of overvoltage online monitoring data acquisition system, particularly discusses the scheme and the function of the second divider circuit, signal transformation circuit, trigger circuit and protection unit controlling circuit. Moreover, it briefly illustrates the operational principle of data acquisition card. Discrete design pattern is chosen as the system software organizing form in this paper. The online monitoring software idea and flowchart are introduced in detail in this paper.The paper accomplishes the adjustment and test to the whole overvoltage online monitoring system. The tests are accomplished in lab by using capacitive bushing as a testing platform. The test results indicate that the design scheme and the realization method brought forward in this paper can satisfy the requirements of overvoltage monitoring in power grid, and obtain the anticipated target.