5.10
SEL-787 Relay Instruction Manual Date Code 20150130
Metering and Monitoring
Metering
Peak demand metering values are stored to nonvolatile memory four times per
day and within one minute of the peak demand metering values being reset.
Demand metering is stored in volatile memory only, and the data will be lost
when power to the relay is removed.
Harmonic Metering
The harmonic metering function in the SEL-787 reports the current and voltage
harmonics through the fifth harmonic and the total harmonic distortion percentage
(THD %). Table 5.8 shows the harmonic values reported. Figure 5.14 provides
an example of the METER H (Harmonic) command report.
Table 5.7 Demand Va l u e s
Relay Option Demand/Peak Demand Values
All Demand/Peak Demand values of line currents IAWn, IBWn, and
ICWn magnitudes (A primary)
Demand/Peak Demand Value of IGWn (residual ground fault
current) magnitude (A primary)
Demand/peak demand value of negative-sequence current
(3I2Wn) magnitude (A primary), where n = 1 or 2 depending on
the winding selected.
=>MET DEM <Enter>
SEL-787 Date: 01/23/2008 Time: 13:46:56
TRNSFRMR RELAY Time Source: Internal
IAD IBD ICD IGD 3I2D
DEMAND (A pri.) 53.9 55.9 54.8 2.1 1.4
LAST RESET = 01/23/2008 13:45:38
=>
Figure 5.12 METER DEM Command Report
=>MET P <Enter>
SEL-787 Date: 01/23/2008 Time: 13:47:00
TRNSFRMR RELAY Time Source: Internal
IAPD IBPD ICPD IGPD 3I2PD
DEMAND (A pri.) 55.8 57.8 56.7 2.1 1.4
LAST RESET = 01/23/2008 13:45:37
=>
Figure 5.13 METER P Command Report
Table 5.8 Measured Harmonic Meter Values
Relay Option Harmonic Values
All Fundamental magnitude (secondary A) and 2nd, 3rd, 4th,
harmonic % values and THD % of line currents IAW1, IBW1,
ICW1, IAW2, IBW2, and ICW2
With Neutral Current
(IN) option
Fundamental magnitude (secondary A), 2nd, 3rd, 4th, 5th
harmonic % values, and THD % of neutral current IN
With Voltage Option Fundamental magnitude (secondary V), 2nd, 3rd, 4th, and 5th
harmonic % values and THD % of voltages VAB, VBC, VCA or
VAN, VBN, VCN
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