Explain the concept of a 'voter' in 2oo3 protection logic and its consequence on tripping.

• A. The voter makes a trip decision based on a single channel's output.
• B. The voter compares all three channel outputs and trips if any one channel indicates a trip.
• C. The voter combines outputs from three channels; a trip occurs only if at least two channels indicate a trip.
• D. The voter bypasses channels during fault conditions.

Answer: (C)

In this arrangement, three independent protection channels monitor the same condition, and the voter sits as the decision point that combines their outputs. The rule is majority: a trip signal is issued only when at least two of the three channels indicate a trip. This gives fault tolerance because a single channel fault—whether it falsely trips or fails to trip—won’t cause a trip unless another channel also signals one. The consequence is a trip that reflects consensus among channels, making the system more robust against spurious trips while still responding promptly when a genuine fault is detected by two channels. If two channels indicate a trip, the system trips; if only one does, no trip occurs, preventing unnecessary trips.