GE LPS-D, Инструкция по эксплуатации

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GE Power Management LPS-D Line Protection System 2-
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2 CALCULATION OF SETTINGS 2.3 PROTECTION SETTINGS
2
When the fault location is calculated to be 100% of the line length, the DTA output is either 0.8 mA DC or 4.0 V
DC. The DTA output goes to full scale (either 1 mA DC or 5 V DC) when the fault location is calculated as
greater than 110% of the line length. Consequently, the usable output ranges are 0 to 0.88 mA DC or 0 to 4.4 V
DC, covering the 0 to 110% fault-location range. The SCADA system should be programmed to recognize a
full-scale output as an indication of an invalid output, resulting from either an out-of-limit fault-location calcula-
tion or a DTA reset.
There are two settings associated with the SCADA DTA Interface. FLTLOCK specifies a time period after a
fault during which fault-location calculations resulting from subsequent faults are prevented from updating
information stored in the DTA logic. FLTRESET specifies the time after a fault at which the fault-location infor-
mation stored in the DTA logic is reset (output forced to full-scale value) and all fault-type contacts will open.
1501: FLTLOCK - Hold Time
Set FLTLOCK to the time following a fault during which fault location calculations resulting from subsequent
faults will not be updated.
1502: FLTRESET - Fault Location Reset Time
Set FLTRESET to the time following a when the fault location information stored in the DTA module is reset
(output forced to full-scale value) and those fault-type contacts that have closed will open. A setting of 0 refers
to an infinite time. For example:
FLTLOCK = 10 seconds
FLTRESET = 5 minutes
With these settings, once the first fault occurs, the DTA module output will not change for subsequent faults
that occur within 10 seconds of the first fault, and the DTA module output will be reset 5 minutes after the last
fault that caused the DTA to produce an output.
2.3.17 OS BLOCKING
Out-of-step blocking (OSB) is a standard feature of the LPS-D. Refer to Section 1.4.4: OUT-OF-STEP BLOCK-
ING on page 1–16 for a complete description of OSB logic. The OSB function is implemented through the LPS-
D distance functions as shown below. For an out-of-step condition, the apparent impedance seen by the relay
will follow a typical swing line as shown in the OSB characteristic. The LPS-D recognizes an out-of-step condi-
tion by sensing that the MOB function operates first, and that the coordinating function (Zone 2, 3 or 4) oper-
ates a short time later. The MOBZONE setting is used to select which of the zones (Zone 2, 3 or 4) is used as
the coordinating zone. Note that Zone 4 can only be used as the coordinating zone when it is set to look in the
forward direction (Z4DIRECTN = FORWRD).
Figure 2–14: OSB FUNCTION CHARACTERISTIC
Swing Line
R
X
MOB
Zone 2, 3 or 4
Zload
A
C
Zc
B