RECLOSER CONTROL EVRC2A-N6,NT http://www.entecene.co.kr
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TECHNOLOGY
7.13. Directional Controls (67)
The directional Controls provide time protection in the direction of power flow. The directional
Controls are necessary for the protection of multiple feeders, when it has the necessity of finding
faults in different directions. The directional controls are composed of phase, neutral, sensitive
ground, and negative sequence overcurrent elements.
If directional controls are selected, it will determine whether current flow in each phase is in
forward or reverse direction, as determined by the connection of the phase CTs, selected
Maximum Torque Angle (MTA), voltage and current phasors. To increase security of all
directional controls, add one power frequency cycle of intentional delay to prevent incorrect
operation.
The directional controls have each three settings. The directional controls settings can be
different in the Primary and Alternate settings.
NOTE :
In case of VD(CVD or RVD) type Recloser, EVRC2A only measures voltages
without checking directional elements.
7.13.1. Phase Directional Controls (67P)
The positive sequence voltage V
1
provides the direction of phase pole in the power system.
The phase direction is determined as comparing the positive sequence voltage(V
1
) to the
direction of the positive sequence current(I
1
). The maximum torque angle is set between ∠0 to
∠359 degree.
The factory default value for maximum torque angle has a lead of ∠300 degree over V
1
.
If the polarized voltage drops below minimum polarized voltage, the phase direction control will
lose direction and will not trip. Then any fault on the distribution line may trip due to the phase
overcurrent element, which is non-directional.
The phase direction control can be programmed for non-direction or to provide a trip for current
flow in the forward or reverse direction only.
Following diagram shows the phasor diagram for I
1
directional polarization in the complex plane.
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