IoTmonitoring and control system of distribution transformers in Rwanda

Abstract

In developing countries many customers do not get good quality of electricity power supply; frequent and prolonged power fluctuations/cuts usually disturb them. Distribution transformer (DT) is a service transformer that provides the final voltage transformation in the electric power distribution system, stepping down the voltage to the level used by the customers. Monitoring and control of DT (as a crucial and expensive asset in the network) is a key enabler of power stability to consumers. A power utility is said to be a business oriented with good image representation if it delivers a reliable and available electricity. Modern technologies such as the Internet of Things (IoT) offer a wide range of applications in the energy sector to smoothly monitor, control and optimize processes. Currently, Electricity Company in Rwanda is not yet implementing the remote system to control and monitor the secondary side of DTs and timely get the notifications of fluctuations/abnormalities occurred on those DTs. That’s why it is still challenging and time consuming to intervene urgently and do the necessary actions to prevent severe power cuts/fluctuations and safeguard the damage of DT itself with customer’s appliances connected on that DT. The secondary side of DT is the one connected directly and supply power to customers. For this reason, we developed an IoT system that automatically detects the abnormalities/fluctuations of three technical parameters of DT (voltage, current and temperature) and vandalism of DT equipment. Once one or all of those technical parameters become abnormal, the system cut off automatically the secondary side of DT and isolate the customers load in 2 seconds, and sends the corresponding short message service (sms) to the authorized person in 5 seconds. In case of movements around the DT (related to vandalism); PIR sensor detects the human motion then camera takes a picture to be sent to the utility with a corresponding sms. In addition, a Buzzer gives an alert warning on the site. If there is no abnormality detected, the system keeps sensing without sending the data to the cloud. This system is also built using current sensors, voltage sensors, and temperature sensor with ATmega 328P Microcontroller to collect and process data from sensors connected to DT system. GSM/GPRS module uploads all the data sensed to the cloud storage and displays them on web application and also sends sms to authorized person. Once there is abnormality, the power relay cut off automatically the secondary side of DT and it can be reclosed remotely to test if the fault has been cleared. This system is powered using a rechargeable battery. A web-based application was developed using PHP, HTML, CSS, and Java Script as the user interface for information visualization. The database for storing sensed data was developed using Mysql and this application was hosted vi to Afriregister Rwanda. This IoT system is designed to maximize efficiency in operations and maintenance, safeguard the DT itself and customers appliances connected on that DT. It prevents as well the vandalism of DT equipment.