| In this paper,the high temperature weather in many places in China this summer caused the power consumption of power grids in 18 provinces such as Beijing,Hebei and Shandong to reach a record high.The national daily power generation also exceeded the highest value of last year for 17 consecutive days.Combined with the new requirements for electric power development in the 13 th Five-Year Plan for Electric Power Development,it is proposed that traditional conventional substations can no longer meet the new requirements of “low-carbon environmental protection,economical efficiency,and green development”,and widely develop intelligent substations construction is imperative.In order to protect the important primary equipment in the power system,ensure the safe and stable operation of the power system,and better adapt to the equipment environment in the intelligent substation,this paper aims to design a new line protection device suitable for the application in the intelligent substation.And the following work was carried out:(1)Analyze the overall architecture of the intelligent substation relay protection system under the current situation,by comparing with the traditional protection devices,the application of the primary and secondary equipment in the intelligent substation and the influence of the platform structure of the “three-layer and two-network” in the station on the operating environment of the line protection device in the intelligent substation are studied.(2)The research determines the basic concept of the protection function design of the device,that is,the basic protection function design of the device under the premise of selectivity,quick action,sensitivity and reliability.It is equipped with various protection types such as distance protection,longitudinal differential protection,overcurrent protection,zero sequence protection,overload protection,and breaker failure protection,and strives to be reasonable in configuration and comprehensive in function.(3)Based on the previous research on the overall architecture scheme and functional design of the protection system,the overall architecture design of the hardware part of the protection device is carried out.For the intelligent substation secondary system,the requirements of fast calculation,high precision and low energy consumption of the device are selected for the DSP chip and ARM chip in the two-chip system.A high-performance,lowpower chip was chosen and a matching power module was designed.(4)Optimize the main program,acquisition program,data processing program,fault handling program,communication program,and human-computer interaction program of the designed chip for the selected DSP and ARM chips respectively.In the aspect of protection algorithm,the advantages and disadvantages of the full-wave Fourier algorithm and the halfwave Fourier algorithm are studied.After the analysis and argumentation of the data,the optimized time-based extraction(DIT)-based 2-FFT Cooley-Tukey method is used.While ensuring the accuracy,the amount of calculation data of the protection device is greatly reduced,and the quickness and reliability of the protection are guaranteed.In this paper,the whole configuration scheme of the line protection device in the intelligent substation is designed from the aspects of protection system architecture scheme,protection function configuration,hardware architecture construction,software program preparation and algorithm optimization.The line protection device based on the two-chip system designed in this paper will be able to meet the new requirements of the line protection device in the intelligent substation under the new situation of global energy Internet. |
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