Power Harmonic Analysis And SVC System Design Of Qiansteel Company

Power quality has severely declined which includes serious voltage deviation and3-phase voltage imbalance with the second phase power supply system in production especially after the2160mm steel mills in operation; curve quality such as bus voltage, current etc. is poor and the harmonic content is excessive by monitoring in the2160mm steel rolling mills, so there is an urgent need to be effective in the treatment.Harmonic monitoring and analyzing system is used for power supply system in our steel company to improve the poor quality and harmonic excessive. It gives the calculation of power system harmonic condition firstly, harmonic current, voltage and distortion levels are calculated through the simulation of power system components and e tabular method which ensures accurate and reliable results. It provides a further guarantee for harmonic controlling by means of monitoring and analyzing.It designs the still-dynamic reactive compensation controller used digital signal processor (DSP) which is based on the discussion of Control systems theory and composition on SVC in order to suppress harmonic effectively, the controller adopts three principles to compensate reactive power, such as vector control of symmetric component, the compensation model of balance theory (i.e., Steinmetz) used imbalance load and voltage synchronous symmetric component; at the same time, it employs calculation method for the thyristor firing control point grounded on reasonable interpolation which greatly improves the SVC control system of control accuracy. It obtains the reactive compensation capacity of the rolling mill production system through its load calculation so as to verify the rationality and reliability of the design, and on which it has required filter selection working.The site results indicates that this design of hardware and software is effective, control method is feasible, SVC system selection and the capacity design is reasonable, system run reliably, the SVC control system for rolling mill can control thyristor pass in real-time and min phase by the change of three-phase voltage and three-phase current, and it also achieves continuous regulation, implementing power factor near0.96, moreover it reaches better control effect for imbalance load when it is real-time effective compensated.