Sel SEL-787 - Section 5: Metering and Monitoring; Metering; Table 5.1 Measured Fundamental Meter Values

5.3
Date Code 20150130 Instruction Manual SEL-787 Relay
Metering and Monitoring
Metering
Metering
The SEL-787 meter data fall into the following categories:
➤ Fundamental metering
➤ Differential metering
➤ Thermal metering: RTD metering (with the external SEL-2600
RTD Module or an internal RTD option)
➤ Energy metering
➤ Maximum and minimum metering
➤ Math variable metering (analog quantities metering)
➤ RMS metering
➤ Analog transducer input metering
➤ Demand and peak demand metering
➤ Harmonic metering
➤ Synchrophasor metering
Fundamental
Metering
Table 5.1 details each of the fundamental meter data types in the SEL-787.
Section 8: Front-Panel Operations and Section 7: Communications describe
how to access the various types of meter data using the relay front panel and
communications ports.
If the winding phase CTs are delta connected, the primary currents displayed
are derived from the secondary values by multiplying them with CTR (CT
ratio) and dividing them by the square root of 3. The phase angles shown are
the same as the secondary values. If the CT connection type is known (DAB or
DAC), the user can correct the phase angles. The MET response is meant to
show steady-state primary values. During unbalanced conditions the primary
line currents cannot be reproduced accurately because the delta-connected
CTs filter out the zero-sequence component of the line current. Wye-
connected CTs do not have any such issue.
Table 5.1 Measured Fundamental Meter Values (Sheet 1 of 2)
Relay Option Meter Values
All Models Line Currents: IAW1, IBW1, ICW1 and IAW2, IBW2, ICW2
magnitudes (A primary) and phase angles (deg)
IGW1, IGW2 (Residual Ground Fault Current) magnitude
(A primary) and phase angle (deg) for Winding 1 and 2
IAVW1, IAVW2 (Average Current Magnitude for Winding 1 and
2) (A primary)
Negative-Sequence Currents (3I2W1 and 3I2W2) (A primary)
With Neutral Current
Option (REF)
IN magnitude (A primary) phase angle (deg)
With Voltage Option VAB, VBC, VCA or VAN, VBN, VCN, VG magnitudes
(V primary) and phase angles (deg)
Average Voltage (L-L or L-N) (V primary)
Negative-Sequence (3V2) (V primary)
Real Power (kW)
Reactive Power (kVAR)