Optimizing Current Injection Technique for Enhancing Resistivity Method

Abstract

Geo-electrical resistivity methods are widely used in various fields and have significant applications in scientific and practical research. Despite the widespread use of resistivity methods, current injection is a critical step in the process of resistivity methods, and the quality of current injection significantly impacts the accuracy of the resistivity measurements. One primary challenge is optimizing current injection techniques to enhance resistivity methods. The developed current injector model for the resistivity meter instrument enhances performance by increasing the voltage source to 400 Volts, extending measurement coverage. It provides three injection current options, 0.5A, 0.8A, and 1A, for efficient accumulator use, considering electrode distances and estimating earth resistance using Contact Resistance Measurement (CRM) to estimate the earth resistance. CRM mode ensures proper electrode connection before injection, thus improving measurement efficiency. The embedded TTGO LoRa ESP32 SX1276 facilitates wireless communication over 1.5 km, addressing challenges in remote and internet-limited areas. The model demonstrates reliability, validity, and durability in CRM mode and current injection measurement. Regarding reliability, we determine the relative error of the model by carrying out measurements repeatedly. In lab-scale testing, the average Relative Error in CRM mode is 0.65%, and in earth resistance measurement testing, it is 1.58%. These relative errors are below the 2% maximum error applied in the “Supersting”, a commercial resistivity instrument. The model's validity is defined by comparing the model with the measuring instrument; we have absolute error. In lab scale testing, the average Absolute Error in CRM mode is 3.08%, and in earth resistance measurement testing, it is 3.73%. The model's durability is tested by injecting current for a minute. After one minute of current injection, the power resistor component's temperature is stable at 30°C.