Research On Simulation Testing System For Relays Of220kV Substation

As the national economic development and people’s daily life essential energy, the application of electricity has become an important indicator to measure the level of developed countries. Especially after the reform and development of the power system from West to East, North and South interconnection, the initial pattern of the formation of a super-massive national grid is interconnected. When the power system break down, its impact and spread are likely to further widen the scope, ranging from affecting the normal life of the people, hinder social production, to endangering public safety, causing serious casualties and loss of social property. Therefore, to protect the power system security, stability causes more and more people’s attention.Protection devices on the security system plays a pivotal role in the stability of electric power system, its malfunction or refusing to move has a huge hazard to electrical equipment and the stability of the grid. Thus the relay test increasingly demanding.This paper describes the history and development of the present situation of the relay tester, analyzes the advantages and disadvantages of microprocessor-based relay test device on the stage, proposes in the new situation, the urgent need for research and development on the test apparatus applicable to the substation site more economical, capable of movement of the test. This paper presents the "PC machine+Interface device "hardware solution to adapt to the new direction of the relay test design, which is different from relay test equipment with previous model using a simple system, the test system is based on a typical substation of220kV system design, application to establish a system of electromagnetic transient algorithm model diagram, in which the transformer is used in a model based on the principle of controlled source, and according to different voltage levels and distances, use the Bergeron model and ordinary π-type equivalent model as the model of the transmission line, and then use simulation to verify the correctness of the model. Furthermore pursuant to the system, this paper developed electromagnetic transient simulation subroutines, to achieve the algorithm.On the basis of previous work and the integration of electromagnetic transient simulation routines, this paper complete a friendly interface test system, and take a series of measures to ensure that the closed-loop feedback to achieve functions of the test system.Interface device accept the current, voltage instantaneous data from the PC and store it to cache, and then read the data from the cache and start D/A conversion, sending needed analog data. Meanwhile interface device can capture analog sent and determine whether the output interface device is working properly, and can be calibrated, and the amount of analog capture feedback to the PC,which can achieve record wave function, while the interface device can show working status of the device with a display and keyboard. This paper presents the A/D module calibration algorithm, manage the sampling points with sine wave curve fit, then the value of the sampling point and the fitted curve corresponding points are compared, if the gap is too large, then remove it identified as the singular point, the remaining samples continue to dealt with sine wave curve fit, until reaching the request.