Design Of The Power Frequency Voltage-Withstand Test Control System Based On S7-300

The requirement for the reliability of electric power supply in electric power system is ever-increasingly high with the improvement of rated voltage. The loss incurred by unreliable equipment insulation far exceeds the value of electrical equipment, but the insulation test is an important method to demonstrate whether high-voltage electric equipment can run reliably and safely on site. Therefore, for high-voltage test electric equipment with alternating current, power frequency voltage endurance test plays an important role in high-voltage technique.The traditional control circuit of power frequency voltage-withstand test is a manual relay system composed of relay and contactor, which performs operating sequence and rate change of ascending or descending voltage. Voltage change by manual control is not very accurate, in the meantime, technician must spend time and vigor analyzing and finding the reason of fault. At the same time, there are some weaknesses of programming complex, expensive, poor anti-interference ability for industrial computer control system. According to these circumstances, this dissertation puts forward a novel power frequency voltage-withstand control system that the nuclear part is a PLC, which can be used with manual control system in parallel.In this dissertation, capacitance divider is selected to measures test voltage in comparison with several kinds of common high-voltage measurement. In the meanwhile analyzing harmonic component based on the Improved Fourier Transformations and designing filter circuit to eliminate harmonic waves of test voltage. The designing of the main circuit of power frequency voltage-withstand control system which consists contact voltage regulator, test transformer, NPS protection equipment and so on. The control circuit consists working mode setting, movement sequence control, and voltage-withstand time setting, voltage regulator position detection and alarming, over-current protection of test circuit etc. In addition, detection circuit of voltage, current, and test voltage are design- ed and over-voltage protection system for transient recovery is developed. Finally, S7-300 program software is applied to programming and debugging digital signal and analog signal. Furthermore, WINCC interface is made to match hardware control system to monitor test.The design of software and hardware in this dissertation meets the need of related test standard specification, improve precision and scientific of test, and attain the target result by debugging.