Keandalan dan pelayanan prima di sistem jaringan tegangan rendah menjadi tolok ukur kinerja PLN terhadap kepuasan pelanggan. Di sistem jaringan tegangan rendah, kondisi trafo di gardu distribusi perlu dipantau. Kondisi trafo dan pemantauan profil beban berkontribusi pada respon tindakan yang perlu dilakukan untuk mempertahankan kinerja trafo. Saat ini, pemantauan profil beban trafo masih dilakukan secara manual oleh personel pemeliharaan secara periodik, yang sulit memberikan gambaran kondisi secara presisi. Untuk itu, diusulkan pemantauan profil beban trafo secara online di PLN UP3 Surabaya Selatan and UP3 Surabaya Utara. Pemantauan secara online berbasis mikrokontroler ESP32. Dari hasil uji coba, peralatan monitoring dapat memberi informasi profil beban yang detail sesuai urutan waktu, serta nilai benefit to cost ratio 1. Dengan demikian, implementasi peralatan monitoring online layak untuk diterapkan di gardu distribusi yang memberi kemudahan monitoring kondisi trafo secara real time sekaligus memberikan manfaat efisiensi biaya operasional. Reliability and excellent service in the low voltage network system are benchmarks for PLN's performance in terms of customer satisfaction. In a Low Voltage Network System, the transformers status at distribution substations needs to be monitored. Transformer condition and load profile monitoring contribute to the response actions to maintain transformer performance. Currently, monitoring of transformer load profiles is still carried out manually by maintenance personnel periodically, which does not provide a precise picture of network conditions. We propose online monitoring system for transformer load profiles at PLN UP3 South Surabaya and UP3 North Surabaya. The online monitoring process was based on the ESP32 microcontroller. The test results show that monitoring equipment can provide detailed load profile information to time sequence and a benefit to cost ratio value of 1. Thus, the implementation of online monitoring equipment is suitable for application in distribution substations that makes it easy to monitor transformer conditions in real time while providing efficiency benefits.