Low-Cost Feedback Control Thermal Protection System for 3-Phase Distribution Transformer Using Microcontroller

Abstract

The design of an efficient and reliable thermal protection system (TPS) for distribution transformers (DT) to eliminate its heating and insulation losses is an important aspect. This paper presents a low cost solution for the feedback control of thermal protection system for 3-phase distribution transformers. It had been observed that overloading in transformer results in temperature increases of its winding and expansion of insulating oil. Without any TPS, it leads to the thermal breakdown of oil and melting of copper windings of the transformer, which is the main cause of enormous losses in the distribution system. To overcome these issues, microcontroller base self-intelligent TPS design is contemplated using various feedback control systems. Temperature sensing unit (TSU) in DT oil tank sends a continuous signal to the controller which interprets this signal to manipulate the function of the cooling system, tripping system and protection failure backup system (PFBS) for DT under excessive overloading. Continuous temperature monitoring and indication have been accomplished through liquid crystal display (LCD) and alarm system. In addition to complete automation in TPS, there will be a liability, to sum up with less human involvement, continuous and convenient monitoring with optimized cost.