EDR-5000
IM02602007E
Parameter Setting of Decoupling
To support dynamical the decreasing voltage (voltage drop) during faults the grid codes of the transmission system
owners (e.g. VDE AR 4120 page 57) require the following behavior during grid problems (voltage sags) by the
connected energy resources:
The QV-Protection supervises the grid compliant behavior after a grid fault. Energy sources that have a negative
impact on the restoration by consuming inductive reactive power have to be disconnected from the grid before
timers of grid protection devices expire.
Therefore the energy source will be disconnected from the grid after 0.5 seconds by the QV-protection if all three
line-to-line voltages at the point of common coupling are less than 0.85 times Vn (logical AND connected) and if
the energy resource consumes at the same time inductive reactive power from the grid (VDE AR 4120 page 57).
The reactive-power of the positive phase sequence system (Q1) is
evaluated.
The voltage supervision only monitors the phase to phase voltages.
This prevents any influence on the measurement through neutral point
displacement in resonant earthed systems.
In the menu [Protection Para\Set[x]\Q->&U<] the »Decoupling« parameters can be set.
The reactive-power demand from the grid can be detected by two different methods. Therefor the decoupling method
»
QV-Method« has to be selected first.
•
Power Angle Supervision (method 1)
•
Pure Reactive Power Supervision (method 2)
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