Individual Harmonic Voltages And Currents - Arbiter Systems Power Sentinel 1133A Operation Manual

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13.7

Individual Harmonic Voltages and Currents

DNP Modbus
Type:Index Input Reg.
AI:128–227 30129-30228
AI:228–327 30229-30328
AI:328–427 30329-30428
AI:428–527 30429-30528
AI:528–627 30529-30628
AI:628–727 30629–30728
Specifying DNP Type Index Values
DNP Harmonic Magnitude
DNP Harmonic Phase Angle = P + 2(n
where: M corresponds to magnitude in the table above, P corresponds to phase in the table above,
and n equals the harmonic number.
Example 1: Specify the type index for the magnitude of the 3rd harmonic of the A-phase voltage.
Type Index Value = M + 2(n
Example 2: Specify the type index for the phase angle of the 5th harmonic of the C-phase current.
Type Index Value = P + 2(n
Scaling and Resolution
Compute actual values from DNP readings as follows: divide the DNP reading by the full-scale
number of counts and multiply by the full scale range. For example, if the DNP reading for voltage
is 21069, and the maximum voltage value is 150, the actual voltage is determined as follows:
Measured Voltage = (21069
Remember that magnitudes are actual scaled primary values and the resolution is determined by
dividing the maximum primary value by the Full Scale count. For example, with a maximum
(1133A) current range of 2.5 Amps (CT ratio of 100), then the resolution is 250
Amps. If the actual primary current is 96.5 Amps, then the DNP reading would be:
Expected Counts = (96.5
Quantity
A Voltage Individual Harmonic Data
(M = 128, P = 129)
A Current Individual Harmonic Data
(M = 228, P = 229)
C Voltage Individual Harmonic Data
(M = 328, P = 329)
C Current Individual Harmonic Data
(M = 428, P = 429)
B Voltage Individual Harmonic Data
(M = 528, P = 529)
B Current Individual Harmonic Data
(M = 628, P = 629)
Table 13.5: Individual Harmonic Voltages and Currents
= M + 2(n
1) = 128 + 2(3
1) = 429 + 2(5
32767) 150 = 96.45 volts
250) 32767 = 12, 648 counts.
DNP 3.0 and MODBUS Data Structures
1)
1)
1) = 132
1) = 437
Full Scale
Vmax=32767
180deg = 32767
Imax=32767
180deg = 32767
Vmax=32767
180deg = 32767
Imax=32767
180deg = 32767
Vmax=32767
180deg = 32767
Imax=32767
180deg = 32767
32767 = 0.0076