Research About Voltage Sag On The Influence Of The Load Of Low Voltage Tripping

With the innovation of new electrical equipment technology, many new equipment and devices is sensitive to voltage fluctuation, and may even small voltage fluctuation can lead to electrical equipment work abnormal or damage. In order to protect the safety of electrical equipment and reduce the economic loss, the power user select to install the terminal circuit breakers with low voltage trip. Under the condition of a wide range of voltage sag caused by the line short-circuit fault, large of load will divest power grid due to low pressure trip action, which influence the power supply reliability and continuity, and may could further aggravate the grid frequency fluctuation and shock. Therefore, the research on the load voltage sag the influence of low pressure trip is of great significance. The main content of this article mainly includes the following three aspects:(1) This paper introduces the basic concept of voltage sag, voltage sag on the effect of different voltage sensitive equipment.(2) This paper introduces the composition of low voltage trip and working principle of its main parts. Besides, power user configuration of low voltage trip(including installation, time delay setting) is introduces and analysis. making the test plan refer to the relevant existing national testing standards. The voltage sag instrument develop by ourselves as test platform, and the five types of low pressure trip which are common in the market as test object, we do experimental tests of low pressure trip and study the characteristics of low pressure trip action(3) This paper introduces the load modeling ideas of low voltage tripping characteristics model. And then introducing the least-square method, this paper derives the constant coefficient non-homogeneous linear equations, which can calculate unknown parameter values of low voltage tripping characteristics model. Finally, according to instance data of the Dongguan main electric power lines short circuit event, calculating low voltage tripping of load model. We can estimated substation load loss by using this model. The model looks for tripping and load voltage sag of connection points from the low pressure trip in different types of user requirements, different types of users load ratio, different types of low pressure trip in voltage drop action features, making the model more practical.