Value reporting
The measurement functions are capable of reporting new values for network control
center (SCADA system) based on various functions.
• Zero-point clamping
• Deadband supervision
• Limit value supervision
In the three-phase voltage measurement function VA, VB, VC the
supervision functions are based on the phase-to-phase voltages. However,
the phase-to-ground voltage values are also reported together with the
phase-to-phase voltages.
GOOSE is an event based protocol service. Analog GOOSE uses the same
event generation functions as vertical SCADA communication for
updating the measurement values. Update interval of 500 ms is used for
data that do not have zero-point clamping, deadband supervision or limit
value supervision.
Zero-point clamping
A measured value under the zero-point clamping limit is forced to zero. This allows the
noise in the input signal to be ignored. The active clamping function forces both the actual
measurement value and the angle value of the measured signal to zero. In the three-phase
or sequence measuring functions, each phase or sequence component has a separate zero-
point clamping function. The zero-value detection operates so that once the measured
value exceeds or falls below the value of the zero-clamping limit, new values are reported.
Table 790: Zero-point clamping limits
Function
Zero-clamping limit
Three-phase current measurement (IA, IB, IC) 1% of nominal (In)
Three-phase voltage measurement (VA, VB, VC) 1% of nominal (Vn)
Ground current measurement (IG) 1% of nominal (In)
Ground voltage measurement (VG) 1% of nominal (Vn)
Phase sequence current measurement (I1, I2, I0) 1% of the nominal (In)
Phase sequence voltage measurement (V1, V2, V0) 1% of the nominal (Vn)
Three-phase power and energy measurement (P, E) 1.5% of the nominal (Sn)
1MAC059074-MB A Section 8
Measurement functions
615 series ANSI 899
Technical Manual
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