Research On Detecting Method And Control Strategy Of Multiple Terminal Unified Power Quality Conditioner

Smart Grid means the intelligent of the Grid and is also be called "Grid2.0". It is an exploration of the future development trend of the grid. Smart Grid is based on highly integrated high-speed bidirectional communication network and the application of advanced sensor measurement technology and advanced equipment to achieve the reliable, safe, economical, efficient operation of the gird and provide power quality service which meets the needs of users of a new era.According to the characteristics of the smart grid and the new requirement of power quality of the power enterprise, a novel kind of the UPQC configuration called the multiple terminal unified power quality conditioner (MT-UPQC) is presented which is based on the research of the active filter in Custom Power and the development of FACTS and HVDC and apply the topology of MTDC to expand the topology of UPQC. The proposed MT-UPQC is consisted of one series active filter and several shunt active filters which share a common dc capacitor. The MT-UPQC can provide high voltage quality and differentiated current quality service to power users in the same feeder according to the power quality requirement and electricity cost requirement of power users. Moreover, voltage control strategy of MT-UPQC which is the voltage of MT-UPQC is controlled by all shunt APF is proposed.In order to achieve the power quality control function of the MT-UPQC, the voltage detection method based on the Park transform and the current detection method based on instantaneous power theory are used. The control strategy of series active filter of the MT-UPQC utilize voltage hysteresis control with differential negative feedback, the control strategy of shunt active filter of the MT-UPQC utilize current hysteresis control. Based on the main circuit topology of the MT-UPQC, corresponding parameter has been calculated.A three terminal-UPQC(3T-UPQC) and a distribution with a3T-UPQC are built on the PSCAD/EMTDC. The simulation results show that3T-UPQC can work stable and3T-UPQC can governance voltage quality problem of all users while provide differentiation current quality services to all users and verify the correctness of the MT-UPQC and its detection methods and control strategies.