Measurement Modes; Directional Overcurrent Characteristics - ABB RELION 620 Series Technical Manual

Section 4
Protection functions
4.1.3.5
4.1.3.6
170
The Blocking mode setting has three blocking methods. In the "Freeze timers" mode, the
trip timer is frozen to the prevailing value, but the TRIP output is not deactivated when
blocking is activated. In the "Block all" mode, the whole function is blocked and the timers
are reset. In the "Block TRIP output" mode, the function operates normally but the TRIP
output is not activated.

Measurement modes

The function operates on three alternative measurement modes: "RMS", "DFT" and
"Peak-to-Peak" . The measurement mode is selected with the Measurement mode setting.
Table 117: Measurement modes supported by 67/51P and 67/50P stages
Measurement mode
RMS
DFT
Peak-to-Peak

Directional overcurrent characteristics

The forward and reverse sectors are defined separately. The forward operation area is
limited with the Min forward angle and Max forward angle settings. The reverse operation
area is limited with the Min reverse angle and Max reverse angle settings.
The sector limits are always given as positive degree values.
In the forward operation area, the Max forward angle setting gives the counterclockwise
sector and the Min forward angle setting gives the corresponding clockwise sector,
measured from the Characteristic angle setting.
In the backward operation area, the Max reverse angle setting gives the counterclockwise
sector and the Min reverse angle setting gives the corresponding clockwise sector, a
measurement from the Characteristic angle setting that has been rotated 180 degrees.
Relay characteristic angle (RCA) is set positive if the operating current lags the polarizing
quantity and negative if the operating current leads the polarizing quantity.
67/51P
x
x
x
1MAC504801-IB E
67/50P-1 and 67/50P-2
x
x
x
620 series ANSI
Technical Manual