Woodward HighPROTEC - Page 817

Protective Elements
Starting Method
A distance protection element of the generator phase distance protection can only be started to evaluate the faulted
impedances if some starting conditions are fulfilled. These conditions depend on a settable starting method:
• »Start condition« = “Overcurrent”: The starting condition is fulfilled if maximum measured phase current
exceeds the settable current limit »I> Str« .
• »Start condition« = “Overcur & Undervlt”: The starting condition is fulfilled if maximum measured phase
current exceeds the settable current limit »I> Str« and the minimum measured voltage is lower than the
settable limit »V< Str« . The additional setting »Voltage type« selects whether phase-to-phase or phase-to-
neutral voltages shall be used.
• »Start condition« = “Underimpedance”: The starting condition is fulfilled if the corresponding measured loop
impedance is lower than the settable limit »Z< Str« .
Impedance Operating Characteristic
For each distance protection element an impedance operating characteristic with direction boundary can be
configured.
Direction boundary: Two settable angles define two directional lines, which start at the origin of the impedance
plane. These two lines define the forward and reverse (backward) areas. The area on the right side of the two
direction lines is defined as forward (green color in the following diagram), whereas the remaining area (shown in
yellow color) defines the reverse direction. The setting »Direction enable« = “active” enables this feature.
Definition of forward and reverse (backward) areas.
817 MCDGV4 DOK-HB-MCDGV4-2E
PDIS_Z03
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