The Design And Practice Of Xindu 500KV Substation Insulation On-line Monitoring System

The equipments' voltage level in Xindu 500 k V substation is from 66 k V to 500 k V,considering the high voltage equipments have a huge number,according to the conventional overhaul methods,the equipments' insulation condition must be checked by preventive trail after the power cut off.In fact,it is almost impossible to experiment with all the equipments within the planed outage time.Furthermore,during the interval of two preventive trails,the electrical equipment insulation problem is likely to occur.To discover the equipment's hidden trouble of insulation,deal with the insulated problem in time,keep the insulation in a normal level and reduce the incidence of grid accidents effectively,the insulation online monitoring system is planed to be installed in Xindu substation,which can real-time monitor the insulation state in the background server and realize the state overhaul of electrical equipment.Technology of electrical equipment insulation online-monitoring can real-time monitoring equipment status and assess the state of equipment in advance to achieve the state overhaul and prevent failure.When establishing the basis of equipment performance evaluation,the system can improve equipment availability,prolong the service life of equipment,reduce unnecessary preventive test after power outage,make reasonable arrangement of power outage plan and improve the economic benefit of power grid and customer at the same time.The characteristic value needed to be monitored by electrical equipment insulation online monitoring system through analyzing the effects on equipment operation caused by insulation property in the paper.The specification and type of the current sensor,voltage sensor and online monitoring unit is chosen by analyzing the performance of the current sensor,voltage sensor and the online monitoring IED unit and combining with the actual situation of Xindu 500 k V substation at the same time.In this paper,the working principle of electrical equipment insulation online monitoring system is analyzed and the structure of hardware and software is designed.The structure of the on-line monitoring system's hardware is made up by adopting voltage sensor,current sensor,A/D conversion circuit,SCM,data interface of RS485,intelligent electronic Device monitoring unit and other accessories.The realization of software design is based on the form of browser/server and adoption of three layer architecture which are the customer layer,middle layer and data layer to design the system.The background server which is set up in the station level communicates with the online monitoring unit in the scene.The online monitoring unit can collect electrical equipment's data such as the leakage current,bus voltage,dielectric loss value and times of lightning strike and connect the server side through CAN bus to implement the data transmission.Process quality control must be noted during the construction in order to make the on-line monitoring system work well.The system achieves to finally monitor electrical equipment's insulation of the substation online finally and can query and analysis data.Xindu 500 k V intelligent transformer substation monitors online the insulation of two main transformer,sixty capacitor voltage transformer,fifty-four lighter.At present,the system in Xindu 500 k V intelligent substation is operating well.