Centralized Protection System Of Spot Networks

Spot network has the advantages of high service reliability and low cost.Spot network has been in operation in very important facilities,for the reasons given above,spot network has been in operation for many years in the United States,for hospitals,airports,government buildings,and other important institutions of power supply.Most spot network protection scheme is distributed protection,it exist mismatch between protection and low operating reliability problems.Substation centralized protection collect the entire information focused on a single computer,form a reliable,flexible and diverse complementary centralized protection system.This paper introduces the concept and characteristic of spot network and analysis structure and existing problems of spot network protection scheme.In protection scheme,mismatch in the outlet and inlet line of low voltage protection cause backup protection misoperation or long action time easily.In addition,mismatch between the inlet line of low voltage protection cause the unfault line protection misoperation easily.According to the deficiency in existing protection schemes to add blocking signal improvement scheme is put forward.Through the PSCAD simulation the scheme of improvement.The results prove that after adding atresia logic protects the reliability and selectivity was improved.Due to the distributed protection,such as information isolation and protection device redundancy problem has not meet the requirements of modern power grid for power supply reliability and economy.Traditional spot network protection scheme belongs to the distributed protection,this paper will apply centralized protection technology to the spot network and designed a spot network centralized protection system.Put forward two aspects of hardware and software design.In the aspect of hardware design a centralized protection system based on Blackfin processor.In the aspect of software is presented based on the design scheme of the Linux operating system.Gives the summary spot network centralized protection system composition.At least,use laboratory equipment of smart grid research center of Shandong University of Technology construct experimental platform.Through XBJ-300 carry out part of the proposed protection scheme in this paper.Compared with the traditional distribution network spot network has the power of special structure of high reliability,low running cost.Existing spot network protection scheme is distributed protection,can’t exert its advantage.In this article,through add atresia logic circuits between the outlet and inlet line of low voltage protection and the line between low voltage,applied centralized protection technology to spot network,designed improved spot network protection system.Simulation and experimental results show that the scheme is feasible.As the user of the power supply reliability requirements gradually improve,spot network centralized protection will have broad application prospects.