VAMP 135 Over-, under- and residual voltage relay with frequency protection relay

Phase Mode

Line Mode

Line Mode+Uo

1. The relay is connected to phase voltages U_L1, U_L2 and U_L3.

2. The main voltages are calculated using the measured phase voltages.

3. The residual voltage is calculated using the measured phase voltages.

4. No open-delta transformer is needed.

1. The relay is connected to phase-to-phase voltages U₁₂, U₂₃ and U₃₁.

2. The residual over voltage stages Uo> and Uo>> are not available.

1. The relay is connected to phase-to-phase voltages U₁₂, U₂₃ and to a residual voltage Uo.

2. The line voltage U₃₁ is calculated using the two measured line voltages.