Study On Plant Power Supply Transfer Based On PSCAD/EMTDC

With the development of modern society, large-scale enterprises such as chemical and steel industries, power plants, need more and more reliable power supply. Once the main power source is interrupted, power supply transfer devices will quickly switch the main loads to the reserved source in order to guarantee the enterprises operating continuously. Unreasonable transfer may cause transfer failed and result in serious damage. Since modern power loads are mainly induction motors with different features, it is essential to study the influence of induction motor parameters on various power supply transfer. In this thesis, we mainly focus on the study of induction motor grouping aggregation and the influence of induction motor parameters on power supply transfers based on the PSCAD/EMTDC program. The main work is as follows:1. Induction motor grouping aggregation methods are compared and a method suitable for power supply transfer is presented. The method is based on the motor aggregation used in transient stability studies, i.e. aggregation by the motor capability. According to the requirement of power supply transfer, a grouping method is then provided to reduce the aggregation error. It guarantees that the motor characteristics in one group are similar. Finally, the presented method is validated numerically on a typical thermal power plant using PSCAD/EMTDC.2. It is very important for the enterprises to choose appropriate power supply transfer scheme according to their requirement and their load composition. Since loads are mainly induction motors in modern enterprises, the influence of induction motor key parameters on power supply transfer is deeply studied. In this thesis, three transfer schemes are considered, which are high-speed transfer, synchronization capture transfer and residual voltage transfer. It is found that the high-speed and synchronization capture transfers are mainly affected by the motor inertia and load factor. While rotor resistance, excitation reactance and load factor mainly have influence on residual voltage transfer.Study of this thesis is helpful to design more effective power supply transfer device and select appropriate transfer method. However, the main results of this thesis should be verified in the future.