Data Type G125 - GE MiCOM P40 Agile Technical Manual

SCADA Communications
MiCOM P40 Agile P442, P444
The G28 part of the value is the truncated per unit quantity, which will be equal to 64 (40h).
The multiplier is derived from the VT and CT ratios set in the relay, with the equation
((CT Primary) × (VT Primary)/110 V). Therefore, the G27 part of the value will equal 1.
Hence the overall value of the G29 register set is 64×1 = 64 W
The registers would contain:
30300 - 0040h
30301 - 0000h
30302 - 0001h
Using the previous example with a VT ratio = 110,000V; 110V and CT ratio = 10,000A:1A
the G27 multiplier would be 10,000A × 110,000 V/110 = 10,000,000. The overall value of
the G29 register set is 64 × 10,000,000 = 640 MW. (Note that there is an actual error of
49 MW in this calculation due to loss of resolution.)
The registers would contain:
30300 - 0040h
30301 - 0098h
30302 - 9680h
3.9.2

Data type G125

Data type G125 is a short float IEEE754 floating point format, which occupies 32 bits in two
consecutive registers. The high order byte of the format is in the first (low order) register and
the low order byte in the second register.
The value of the G125 measurement is as accurate as the relay's ability to resolve the
measurement after it has applied the secondary or primary scaling factors as require. It
does not suffer from the truncation errors or dynamic range limitations associated with the
G29 data format.
P44x/EN SC/Hb6
(SC) 12-33