Design Of On-line Monitoring Device For Grounding Current Of Transformer Core

The transformer is the core part of the power system.,the failure rate of the transformer core directly affects the ability of the transformer and even the entire power system to operate safely and reliably.In order to reduce the Occurrence rate of Transformer core grounding fault,real-time monitoring of transformer core ground current.Therefore,This article designs a transformer core ground current on-line monitoring device.It is very important to improve the safety and reliability of transformer operation.This paper analyzes the measurement of grounding current theoretically:determined the difficulty of measuring the ground current compared with conventional alternating current,and design a program to measure the ground current by using an analog switch.Analyze the previous AC-DC conversion method,further design a programme for realizing AC-DC conversion by using a high-precision single-supply absolute-value circuit.Device working environment is outdoor,and needs strong anti-interference,innovative design of a dynamic hysteresis filter scheme to filter out interference signals.Design all hardware circuit structures and corresponding software systems of the device,improve the entire monitoring device.Analysis shows poor linearity measurement near transformer zero,design the Method of Subsection Poly line Approximation to Calibrate and the Device Linearity analysis.Low temperature experiments for the device,make sure the device can accurately realize the monitoring function of ground current under the constant change of outdoor temperature.The designed On-line Monitoring Device for Grounding Current of Transformer Core can realize the real-time monitoring of the ground current,the alarm when the fault current value is exceeded,the query of historical current data,and the preservation of the history current maximum value.The application of this device can bid farewell to the traditional human inspection of the regular inspection mode of failure,to a large extent,save manpower and material resources,improve the accuracy of iron core ground current measurement,reduce the failure rate of the transformer core,thus improve the power system power supply efficiency.