Generator transformer unit protection is a unit protection scheme designed for generator-transformer blocks in power plants. It protects the generator, step-up transformer and connection equipment against internal faults, abnormal operating conditions and external system disturbances. Written by Leon Zhang, Protection…

Transformer fault types refer to the electrical, thermal, mechanical and insulation faults that can occur inside a transformer or in its external connections during operation. Common transformer faults include winding short circuits, inter-turn faults, earth faults, bushing faults, core faults,…

Types of transformer protection split into electrical relays and mechanical devices, each aimed at a different fault mode. Written by Leon Zhang, Protection Application Engineer · Technical review by Li Ming, Electrical Engineer · Last reviewed September 2026. Transformer Faults and…

Introduction A Phase Protection Relay is specifically designed to monitor three-phase power systems and disconnect equipment when dangerous phase conditions are detected. Properly applied phase protection can significantly reduce maintenance costs, improve system reliability, and extend equipment life. In this…

Transmission line protection relays combine ANSI 21 distance, 87L line differential, 67 directional overcurrent and 50/51 backup in one device. They find a fault, decide which breaker opens, and open only that breaker. Everything else keeps running. Each function answers one…

Transformer protection devices cover every fault a unit can see, from winding short circuits to rising gas pressure. Written by Leon Zhang, Protection Application Engineer · Technical review by Li Ming, Electrical Engineer · Last reviewed September 2026 Power Transformer Protection…

otection Relay A step-up transformer protection relay is the protection scheme used to protect a transformer that raises the generator voltage to a higher transmission or grid connection voltage. Also known as generator step-up transformer (GSU) protection, it is a…