Unit Protection Principle Explained | Circulating Current & Balanced Voltage Protection

Unit Protection Principle Explained | Circulating Current & Balanced Voltage Protection | Differential Protection #UnitProtection #DifferentialProtection #PowerSystemProtection #ProtectiveRelays #ElectricalEngineering #TransformerProtection #TransmissionLineProtection #CurrentDifferential #BalancedVoltage #PowerSystem #CircuitMasterclass #GATEElectrical #PSUExam #Substation #engineeringeducation In this lecture, we discuss one of the most important concepts in Power System Protection—Unit Protection Principle. Unlike time grading, current grading, directional protection, or distance protection, unit protection protects only a specific equipment such as a transformer, generator, transmission line, or feeder. It operates only for internal faults and remains completely stable during external faults, even when heavy fault current passes through the protected equipment. In this video, you'll learn: Why conventional discrimination methods are insufficient for interconnected power systems What is Unit Protection? Circulating Current Principle (Current Differential Protection) Balanced Voltage Principle (Opposed Voltage Principle) Current Balance Discrimination Internal Fault vs External Fault operation CT connections and pilot wire schemes Numerical examples with CT ratios Relay operation during healthy, external, and internal fault conditions Differential current (spill current) concept Practical applications in transformers, generators, feeders, cables, and busbars This lecture is ideal for: Electrical Engineering students GATE aspirants PSU examinations SSC JE Diploma Engineering Utility engineers Substation and Protection Engineers If you found this video helpful, don't forget to Like, Share, Subscribe, and press the Bell Icon for more power system protection tutorials. Link of our website : https://circuitmasterclass.com/