Research on Integrated Method to Detect Internal Resistance of Substation Battery

This paper presents a new substation battery internal resistance on-line detection method based on DC discharging internal resistance detection and AC impedance detection. DC internal resistance of battery can be obtained by means of calculating the difference of electromotive force of cells and discharge voltage of load during the battery discharge. Four-wire AC impedance test results obtained online can be influenced by component tolerances of detection circuit and ripple current of charger. The integrated detection method of battery internal resistance, combined DC discharge method and AC impedance detection method, has been running for five years in the substation. The detection data of battery internal resistance showed that the integrated method improved detection accuracy and reduced the impact of noise of charger and component tolerances of detection circuit.