To address the problems of insufficient real-time monitoring data, insufficient accuracy, and low reliability of current power grid monitoring systems, we offer intelligent online monitoring technology research of green energy transmission and conversion devices based on Internet technology. The sensor tag is integrated with various electrical equipment status monitoring sensors, so that the electrical equipment status acquisition terminal has the ability of recognition and perception. Firstly, the propagation characteristics of electromagnetic wave in substation are analyzed, and the propagation path loss model of electromagnetic wave is established. Secondly, a multiantenna RFID system is proposed to solve the problem of electromagnetic wave multipath effect. Moreover, the communication channel model of substation multiantenna (radio frequency identification, RFID) monitoring system is established, the factors affecting the performance of substation multiantenna RFID system are analyzed, and the precautions for the installation of multiantenna RFID system are put forward. A new anticollision algorithm is proposed compared to the traditional algorithm, based on the interference of collisions between the sensor markings of the multiantenna RFID control system in the substation. The results show that as the number of sensor markings increases, the total duration of the enhanced adaptive time slot and multitree search collision (improved adaptive time slot and multitree search anticollision, IATMSA) algorithm is always less than that of the IAMS algorithm and the square algorithm, basically maintained at 50% to 60%, up to about 75%. In the improved adaptive multitree search (improved adaptive multitree search, IAMS) anticollision algorithm, the IAMS algorithm determines the choice by calculating the size of the collision factor. The binary tree algorithm is basically about 45%, and the quadtree algorithm is basically about 30%. Figure shows the online monitoring technology for power transmission and conversion devices based on Internet of Things technology.