Alstom MiCOM P846, Technical Manual

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P846/EN AP/D Application Notes
(AP) 6-6
MiCOM P846
AP
Reliability:
The DLO must detect the open-close status of a line at both ends for the
following categories of phenomena:
−
Line closing or opening at local end (with or without a shunt reactor connected)
−
Line opening at remote end (with or without a shunt reactor connected) with line
charging current measured by the DLO
−
Line closing at local end when already open at remote end. MW surge and line charging
measured by the DLO
−
Line opening at both ends with 100% compensation with shunt reactors
−
Line opening with residual CT current measured by the DLO
−
Closing of a line at remote end with DLO measuring line voltage and shunt reactor
current
Security:
False detections must be avoided in the following categories of phenomena:
−
Fault occurrence with reversal of current direction on the line
−
Low or very low power transfer on the monitored line
−
Distortion on line voltages and currents during faults
−
Fast variations in the line power flow
−
Reversal of power flow direction
−
Power oscillations
−
Sub-synchronous resonances
−
Presence of harmonics
Speed:
The DLO must detect any change in the line status in 35 ms or less.
−
This response time includes the effects of the CTs magnetizing discharge currents, the
DLO internal filters and the delay of its output contacts.
2.3 Setting guidelines
The primary settings related to this protection functions can be found in the relay menu "VT
AND CT Ratio" needed to specify the DLO operation parameters.
Menu Text Default setting Setting range
Min. Max.
Step size
Main VT Primary 735kV 100V 1000kV 1V
Main VT Sec'y 120.0V 80V 140V 1V
Phase CT Primary 2000A 1A 30 1A or 0.01kA
Phase CT Sec'y 5.000A 1A 5A 4A
Phase CT2
Primary 2000A 1A 30 1A or 0.01kA
Phase CT2 Sec'y 5.000A 1A 5A 4A
CVT Enable Enabled Disabled/Enabled
CVT Threshold 10% 1 100 0.1%
Tie-Line Factor Disabled Disabled/Enabled
Base Power 2.081 GW 0 5.000G 1W
Line Charging 20.81 MVar 0 5.000G 1Var
Table 2 Primary settings of the DLO