Research And Realization Of Key Techniques Of A FTU Based On Local Intelligence Combined With Combined With Remote Intelligence

Some disadvantages of intelligent switches based Feeder Automation(FA)and computertogether with communication network based FA are pointed out．A new scheme based onlocal intelligence combined with remote intelligence is described．Restoration and isolation offaults are carried out by local intelligence,which is independent of communication．Theremote intelligence is used to automatically shift the setting values of each FTU when thetopology of the Distribution Network(DN)changes．The monitoring and optimal operation ofthe DN are also realized by the remote intelligence． Some key Techniques of a Feeder Terminal Unit(FTU)based on the proposed scheme are investigated． A novel algorithm based on reclosers and voltage-current-mode pole-mounted sw~ches(RVC)based FA is put forward．The time of temporary faults restoration can be greatly reduced．As for permanent fault isolation and restoration,the reclosing procedure is only committed once and the residual voltages are not necessary in the detection of fault as well． The relationship between the error of the cycle of the signal being measured due tointeger conversion of the sampling interval and the round is obtained,based on which,a Dynamic Sampling Interval Adjustment method(DSIA)is deduced．As a result,the accuracy of measuring is effectively increased． The interface circuit between TMS320F206(a non—multiplexed address／data bus)and SJA 1 000(a multiplexed address／data bus)is designed by using complex programmable logic device(CPLD)． The proposed algorithms are realized on the platform of a FTU based on data signal processing microprocessor(DSP)．The experiment results show that the procedures of faulttreatment are in accordance with the design and that by the proposed DSlA the accuracy of voltage and current measurement increase from O．5％to 0．2％and the accuracy of power measurement increase from 1.0％to 0.5％．...