| Reactive power is one of the important indexes of maintaining the safe and reliable operation of the power networks. A Thyristor Switched Capacitor (TSC) type dynamic reactive compensator applied in low voltage distribution networks is designed by combining the development and situation of reactive compensators.The paper mainly discusses the principle and correlative technique problems, Matlab/Simulink system simulation, the hardware and software design of controlling system. The different methods of TSC switched time, controlling parameter detection and strategy are compared and the final controlling scheme is determined, that is, using the controlling strategy of reactive power which is measured and TSC switched at the time of zero-cross power supply. The feasibility of the controlling method is reseached by building each of the function modules on the aspect of system simulation, In hardware design, signal sampling, true root mean square calculation, synchronous signal detection and user-machine interface circuit are designed on the basis of PIC minimum system which is given full play to for the advantages of fast operation, rich interface resources, high perfprmance-price ratio and in-circuit debugger. Meanwhile, main circuit, triggering and driving circuit for TSC are also builded. In software design, C program language is applied in the controlling method and triggered controlling signals by means of modularization. In order to realize real-time display of controlling physical quantities, programs of liquid crystal display are added.Finally, TSC dynamic reactive compensator is experimented through a single-phase whole-bridge rectifier with resistance-inductance load simulating the changes of reactive power in practical power networks on a debugging platform. Results prove that the dynamic reactive compensator runs stably and reliably. The device can actualize capacitor’s speediness, no percussion switching, avoid oscillation and meet design requirements accordingly. |
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