Schweitzer Engineering Laboratories SEL-700G Series, Instruction Manual

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5.7
Date Code 20170814 Instruction Manual SEL-700G Relay
Metering and Monitoring
Metering
Maximum and
Minimum Metering
Maximum and minimum metering allows you to determine maximum and
minimum operating quantities such as currents, voltages, power, analog input
quantities, RTD quantities, and frequency. Table 5.4 lists the max/min
metering quantities.
All maximum and minimum metering values include the date and time that
these values occurred. The analog quantities from Table 5.4 are checked
approximately every 0.5 seconds and, if a new maximum or minimum value
occurs, this value is saved along with the date and time that the maximum or
minimum value occurred. Maximum and minimum values are only checked if
relay element FAULT is deasserted (no fault condition exists) for at least one
second.
Additionally, the following minimum thresholds must also be met (n = X or Y
for X or Y-side quantities):
➤
Current values I
A
n, I
B
n, I
C
n, and I
N
: 3% of the nominal CT
rating.
➤
Current values I
G
n: I
A
n, I
B
n, and I
C
n all must be above their
thresholds.
Table 5.4 Maximum/Minimum Meter Values
Relay Option Maximum/Minimum Meter Values
X-Side Maximum/
Minimum Quantities
(model dependent)
➤
Input currents IAX, IBX, and ICX magnitudes (A primary)
➤
Calculated currents IGX (IGX = 3I0 = IAX + IBX + ICX)
(A primary)
➤
Wye-connected input voltages (with respect to neutral): VAX,
VBX, and VCX magnitudes (V primary); Calculated voltages
VGX (VGX = 3V0 = VAX + VBX + VCX) (V primary)
➤
Delta-connected input voltages: VABX, VBCX, and VCAX
magnitudes (V primary)
➤
Three-phase (P3X) real power (kW)
➤
Three-phase (Q3X) reactive power (kVAR)
➤
Three-phase (S3X) apparent power (kVA)
➤
Frequency (FREQX) in Hz.
Y-Side Maximum/
Minimum Quantities
(model dependent)
➤
Input currents IAY, IBY, and ICY magnitudes (A primary)
➤
Calculated currents IGY (IGY = 3I0 = IAY + IBY + ICY)
(A primary)
➤
Wye-connected input voltages (with respect to neutral): VAY,
VBY, and VCY magnitudes (V primary); Calculated voltages
VGY (VGY = 3V0 = VAY + VBY + VCY) (V primary)
➤
Delta-connected input voltages: VABY, VBCY, and VCAY
magnitudes (V primary)
➤
Three-phase (P3Y) real power (kW)
➤
Three-phase (Q3Y) reactive power (kVAR)
➤
Three-phase (S3Y) apparent power (kVA)
➤
Frequency (FREQY) in Hz.
Other Maximum/
Minimum Quantities
(model dependent)
➤
Synchronism-check voltage input (VS) magnitude (V pri-
mary)
➤
Neutral voltage input (VN) magnitude (V primary)
➤
Third harmonic voltages for stator ground element 64G
(Wye-connected X-side PTS only):
➤
Third harmonic voltages VPX3
(VPX3 = VAX3 + VBX3 + VCX3) and VN3 (V primary).
➤
RTD1-RTD12 temperatures (°C)
➤
Analog input values (±20mA, ±10V) in engineering units