Design And Implementation Of Power Quality Control System For Yangshan Port Power Distribution Network

Shanghai Yangshan Deepwater Port is well-know in the world by its special geographical location, which away from the electric power supply. The electric power system in the port is connected with the power grid by a long-distance transmission cable, and the short-circuit capacity of the system is small, and the anti-interference ability of the system is weak. We found several power quality problems since the opening of Shanghai Yangshan Deepwater Port, like electric power system frequent oscillation, voltage fluctuation and flicker exceed the standard. With the continuously increasing of port crane bridges and their loads, the probability of low frequency oscillation events occur more frequently, then seriously affect the electric power system and crane bridges in the aspect of the safe and stable operation.This paper researches the origin of the control scheme and software realization process based on the power quality problem in Shanghai Yangshan Deepwater Port electric power system. In this paper, based on the onsite test data of the electric power system, we found that the interharmonics current causes the oscillation of the system, and the voltage fluctuation and flicker exceed the standard. This paper discusses the different solutions and their insufficient. The further, we put forward a comprehensive solution based on super capacitor. The structure and composition of the scheme are introduced in detail in this paper. At the same time, the effect is tested and analyzed after the power quality control device is operated. The indicators of improvement rate more than 90% in basic. This result shows that the control effect is obviously success. This also further verified the source of power quality problems and rationality of the control scheme.This paper based on the actual problems of power quality, with a field test data, and achieved actual results in engineering practice; therefore, the paper can provide reference to other port electric power system oscillation, voltage fluctuation and flicker control, so it has important engineering application value.