Explain why reverse power protection is necessary for alternators in parallel operation, sketch a reverse power trip, and explain its principle and activation?

flowchart LR
    A[Generator] -->|power| B[Current Transformers]
    B --> C[Reverse Power Relay]
    C -->|Contacts close| D[Trip Coil]
    D --> E[Circuit Breaker]
    E --> F[Busbar]
    G[Trip Supply] -->|supply| D

• Purpose: Prevent mechanical damage to prime mover and maintain system stability
• Condition: Motoring effect when mechanical input < electrical output demand
• Regulation: Recommendation 182 §3.6.1 requires trip and alarm
• Principle: Reverse power relay detects power absorption from busbar
• Activation: Relay closes contacts, energizes trip coil, opens circuit breaker
• Officer action: Verify protection before paralleling, monitor alarms, isolate and investigate on trip