Equipment Research And Development Replying In Voltage Sag Recovery Based On Sensitive User

With the development of science and technology and the expansion of industry scale, electricity consumption is increasing in all national sectors.New technology and new process are widely used in the production and all aspects of people's life with the increasingly high degree of electrification.More and more users prefer to use high-tech equipment which has good performance, high efficiency but is voltage sensitive, such as computer information management systems, automated production line,high-precision measuring instruments, precision CNC machine tools. These systems and equipment are very sensitive to a variety of grid disturbances.Any power quality problems may lead to enormous social and economic losses and poor social impact. So users have increasingly high demand in power supply reliability and power quality. Supplying quality and reliable power from existing urban distribution system to urban load centers will face increasing difficulties and challenges. Finding the way to solve the power quality problems like voltage sag is particularly necessary and urgent.This paper will analyze voltage sag including voltage causes, the influence of voltage sag to sensitive load. Different sensitive equipment is also analyzed. On this basis, several voltage sag solutions are comparative analyzed including DVR, UPS, superconducting magnetic energy storage,STATCOM, super capacitor and VSC-HVDC from the point of view of economy, scope of application and the governance effect. Finally the comprehensive solution to voltage sag is raised.On this basis, a typical industrial load simulation is established by PSCAD in this paper. And a variable parameter STATCOM control strategyis also raised. Besides, it gives the hardware design and software design. The hardware design includes the detailed wiring diagram and the device list. The software design includes A/D sampling program, algorithm, DC boost, PWM pulse output, CAN bus communication, relay control, protection logic,external digital input signal acquisition.Finaly, the practical application of the device significantly inhibits voltage sag occurs raises the load voltage, improves power factors and guarantees the safe and stable operation of the load.