Analysis And Design Of Intelligent Segmented Switch Controller Based On ARM

With the continuous development of the Smart Grid,our country has raised higher requirements on the aspects of reliability,security and economic benefits of electric energy production and distribution.The distribution grid is located in the end of the power transmission system,followed with power users.It has been an extremely important node to the overall performance of the electrical power system.Due to the restriction of wide range and large quantity,the distribution grid of lOkV system is behindhand in automation and will be the key point in the construction of the Smart Grid.With the functional requirements and industrial standard into consideration,this paper has researched and designed a multifunctional smart controller of sectionalizing switch based on the core of ARM.First of all,the working principles of sectionalizing switch are analyzed and the action basis and process of over-current protection,current instantaneous trip protection and zero-sequence protection are designed.An algorithm of subsection location is designed based on zero-sequence power direction.Then several kinds of AC sampling algorithms are compared and the optimization design of DFT is made.Next the analysis and summary for the functions of the smart controller are finished based on the requirements of Distribution Automation.This paper has designed the hardware part of the system with modular design method as follows:the main control module based on LPC1778,the AC sampling module based on ADE7878,the GPRS module based on SIM800C,the ethernet interface module based on ZNE-100TL,the ZigBee module based on CC2530,the power module,the clock module and the switch input and output module.On the basis of hardware design,the bottom-level driver and the upper application program of each module are designed.At last,the experiment and test on hardware and software of the system are carried out.The result shows that this smart controller has an AC sampling error rates within ±0.5%and can cut the faulty line out within 50ms.It has reliable relay protection functions and friendly interference functions.The system operates stably and can meet the requirements of design.