Design of Intelligent Detection System for Loop Resistance Under High Current

The intelligent detection system of loop resistance under high current was designed by combining with the latest test procedure DL/T 618-2022 for loop resistance of GIS equipment. Based on the high precision and low power consumption of 24-bit Σ-Δ analog-to-digital converter chip, the current output module, voltage measurement module, microprocessor unit and user interface hardware module were system constructed. The resistance voltage division scheme was utilized to realize the switch of the test system gear to ensure the 300A current condition circuit resistance test. And a buzzer alarm circuit was equipped to ensure the application safety. At the same time, the WiFi module was used to transmit and store data in the cloud. The deviation rate between the standard resistance was less than 5%, and the deviation rate between with the loop resistance measurement value of the high-precision benchtop equipment was less than 1% in the actual field test. This indicated the developed system had high application reliability.