State Monitoring System Of Neutral Point Equipment In Distribution Network

In order to meet the ever-increasing demand for domestic electricity and improve the quality of electricity supply,the scale of my country’s power system has been expanding year by year,and the cable lines have become more and more bloated,which has led to the increasing capacitance of the system’s three-phase lines to ground.When a ground fault occurs,the capacitor current is too large and the arc cannot be automatically extinguished,causing safety accidents such as fire.Online monitoring of the status of the neutral point equipment of the distribution network,based on these statuses,can determine whether the current distribution network system is faulty.If a fault occurs,it can be found in time and personnel can be arranged for maintenance,thereby reducing losses and ensuring continuous and stable power supply.The neutral point equipment status of the distribution network that this system needs to monitor includes gear inductance,neutral point voltage,ground inductive current,ground residual current,detuning degree,damping resistance,capacitive current,and ground capacitance.These state parameter values are An important basis for judging whether the distribution network system is in normal operation.In this system,the neutral point equipment parameter monitoring terminal of the distribution network monitors all the neutral point equipment status parameters of the distribution network,and uploads all the status parameters to the local workstation monitoring software based on the Modbus protocol.The local workstation monitoring software uploads the status parameters to the cloud platform Web system based on the Modbus protocol,and also calls the communication program based on the IEC61850 standard to incorporate the status parameters into the intelligent substation integrated automation system of the substation.The main research work of this article is divided into the following three parts.(1)Local workstation monitoring software.The monitoring software is developed based on the LabVIEW graphical programming language,and has functions related to account management such as account login and registration,as well as functions related to processing state parameters such as status parameter display and storage,abnormal state parameter alarm reminders.In addition,in order to upload the monitored state parameters to the cloud platform Web system and the integrated automation system of the intelligent substation integrated into the substation,the local monitoring software also includes a data upload sub-module.(2)Cloud platform web system.By building a Web system,users can access the platform through networked mobile devices at any time to view the monitored status parameters,abnormal parameter alarm reminders and other information.The Web system is developed based on the Java programming language.It has functions similar to local workstation monitoring software,such as account login,status parameter display and storage,and alarm information query.The Web system also solves the problem of Session sharing in the back-end server cluster environment,and solves the problem of Redis cache penetration by implementing Bloom filters.(3)Communication realization based on IEC61850 standard.Establish an IED information model that complies with the IEC61850 standard for the neutral point equipment parameter monitoring terminal of the distribution network,and then use the SCL language to write a suitable ICD configuration file for it according to the information model,and finally complete the IEC61850 standard with the help of the MMS-EASE Lite development kit.MMS protocol mapping realizes the communication program based on IEC61850 standard.First,each module in the system is deployed separately for single function testing.Then connect each part to build a state parameter monitoring experimental platform for overall testing.The experimental results of the unit test and the overall test show that the neutral point equipment status monitoring system of the distribution network designed in this subject is available and practical.