| At present,portrait trunk type grid structure,which possesses many power supply levels and short power supply circuit,is widely applied in coal mine power supply system.Because of the little difference of short-circuit current between start and end point of the structure,the relay protection is difficult to act reliably in coal mine,and it is a serious threat to the safety production of coal mine underground.According to this situation,an in-depth analysis on the existing scheme of anti-grade trip is made,it shows that the real-time communication of comprehensive protector is an important factor to restrict the property of anti-grade trip scheme in coal mine power supply system.RT-Ethernet communicates directly through the hardware address,which economizes the cycle time of Windows stack,it has the characteristics of high transmission speed and flexible network,and it can establish field level network control system.Comprehensive protector,which acts as the field equipment of anti-grade trip system,makes the single network of coal mine anti-grade trip system possible by using RT-Ethernet communication.For this reason,an in-depth study of the comprehensive protector with an Ethernet interface is carried out.Firstly,anti-grade trip scheme based on RT-Ethernet is studied,the publisher/subscriber mechanism of RT-Ethernet communication is analyzed,the anti-grade trip scheme principle based on RT-Ethernet is researched on thoroughly,and the anti-grade trip schemes are compared from the scalability,performance and other aspects of anti-grade trip.Secondly,the anti-grade comprehensive protector based on RT-Ethernet is designed,the anti-grade comprehensive protector technology based on RT-Ethernet is researched on,the protector from hardware and software is designed,at the same time,the communication test between comprehensive protector and master station is completed.And then,the protection algorithm of the integrated protector is studied deeply.The comprehensive protection algorithm fusing Fourier transform,wavelet transform and wavelet entropy is put forward,and the simulation analysis of integrated protection algorithm by MATLAB is carried out.Finally,the anti-grade trip scheme based on the RT-Ethernet is simulated,the anti-grade trip system based on RT-Ethernet is established,the comprehensive protector is simulated by using the PLC controller with Ethernet interface of German Beckhoff company,the feasibility and real-time of anti-grade trip scheme based on RT-Ethernet is proved.The test result shows that the scheme based on RT-Ethernet meets the real-time and selective of the anti-grade trip of the coal mine,it has good application value. |
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