ABB RELION 670 Series Technical Manual page 287

Generator protection

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1MRK 502 066-UUS B

Load encroachment

Each of the six measuring loops has its own load encroachment characteristic based on the

corresponding loop impedance. The load encroachment functionality is always active, but can be

switched off by selecting a high setting.

The outline of the characteristic is presented in figure 138. As illustrated, the resistive blinders are

set individually in forward and reverse direction while the angle of the sector is the same in all four

ANSI05000196 V1 EN-US

Figure 137: Characteristic of load encroachment function

The influence of load encroachment function on the operation characteristic is dependent on the

chosen operation mode of FRPSPDIS (21) function. When output signal PHSELZ is selected, the

characteristic for FRPSPDIS (21) (and also zone measurement depending on settings) will be

reduced by the load encroachment characteristic, see figure 139.

When output signal PHSELI is selected, the operation characteristic will be as in figure 138. The

reach will in this case be limit by the minimum operation current and the distance measuring

Technical manual

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Impedance protection

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