4.36
SEL-734 Meter Instruction Manual Date Code 20090730
Metering
Metering Calculations
The SEL-734 reports this error if the meter overwrites old LDP data with new
data during a response or if an operator issues an LDP C command.
Metering Calculations
The information below details how the SEL-734 calculates various meter data.
The SEL-734 samples analog values at 8000 times per second and performs a
numerical approximation of the integral mathematical equations for voltage,
current, and power. Where possible, these calculations reference the
equivalent mathematical equations in IEEE 1459-2000.
Voltage and Current
Magnitudes
Form 9 (3-element meter)
Voltage: X = Va, Vb, or Vc
Current: X = Ia, Ib, or Ic
Form 5 (2-element meter)
Voltage: X = Vab, or Vcb
Current: X = Ia, Ib, or Ic
Table 4.24 Record Type 0068—SER Data
Field Data
Structure
Field Description Min Max Notes
UINT16 Year of the SER
UINT16 Julian day of the SER
UINT32 Tenths of milliseconds since midnight
UINT16 SER data ENUM
• Repeat timestamp and data for each available SER
•
•
Table 4.25 Record Type 0069—LDP Error
Field Data
Structure
Field Description Min Max Notes
CHAR[25] OVERWRITE OCCURRED String that contains a
description of the error
where:
N = Number of samples; N = 8000 for 1-second update
quantities
x(n) = Array of periodic v or i samples corresponding to X
X
rms
xn()[]
2
0
N 1–
∑
⎝⎠
⎛⎞
N
-------------------------------------=
Courtesy of NationalSwitchgear.com
To Next Page
Loading...
