ABB RER620

1MAC309294-MB F Section 4
Protection functions
RER620 87
Technical Manual
4.1.1.5 Measurement modes
The function operates on four alternative measurement modes: “RMS”, “DFT”,
“Peak-to-Peak” and “P-to-P + backup”. The measurement mode is selected with the
setting Measurement mode.
Table 102: Measurement modes supported by 51P/50P stages
4.1.1.6 Timer characteristics
51P/50P supports both DT and IDMT characteristics. The user can select the timer
characteristics with the Operating curve type and Type of reset curve settings. When the
DT characteristic is selected, it is only affected by the Trip delay time and Reset delay time
settings.
The relay provides 16 IDMT characteristics curves, of which seven comply with the IEEE
C37.112 and six with the IEC 60255-3 standard. Two curves follow the special
characteristics of ABB praxis and are referred to as RI and RD. In addition to this, a user
programmable curve can be used if none of the standard curves are applicable. The user
can choose the DT characteristic by selecting the Operating curve type values “ANSI Def.
Time” or “IEC Def. Time”. The functionality is identical in both cases.
The following characteristics, which comply with the list in the IEC 61850-7-4
specification, indicate the characteristics supported by different stages:
Measurement mode
Supported measurement modes
51P 50P-1 50P-2
RMS x x
DFT x x
Peak-to-Peak x x
P-to-P + backup x
For a detailed description of the measurement modes, see the General
function block features section in this manual.