GE Digital Energy L60, Инструкция по эксплуатации

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CHAPTER 5: SETTINGS GROUPED ELEMENTS
L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUAL 5-239
5
proper operation even if the negative-sequence voltage at the relaying point is very small. If this is the intent, the offset
impedance shall not be larger than the negative-sequence impedance of the protected circuit. Practically, it is several
times smaller. Enter the offset impedance in secondary ohms.
NEG SEQ DIR OC1 TYPE
— Selects the operating mode for the overcurrent unit of the element. The choices are “Neg
Sequence” and “Zero Sequence.” In some applications it is advantageous to use a directional negative-sequence
overcurrent function instead of a directional zero-sequence overcurrent function as inter-circuit mutual effects are
minimized.
NEG SEQ DIR OC1 POS-SEQ RESTRAINT
— Controls the positive-sequence restraint. Set it to 0.063 (in “Zero Sequence” mode) or
0.125 (in “Neg Sequence” mode) for backward compatibility with revisions 3.40 and earlier. Set it to zero to remove the
restraint. Set it higher if large system unbalances or poor CT performance are expected.
NEG SEQ DIR OC1 FWD ECA
— Select the element characteristic angle (ECA) for the forward direction. The element
characteristic angle in the reverse direction is the angle set for the forward direction shifted by 180°.
NEG SEQ DIR OC1 FWD LIMIT ANGLE
— Defines a symmetrical limit angle (in both directions from the ECA) for the forward
direction.
NEG SEQ DIR OC1 FWD PICKUP
— Defines the pickup level for the overcurrent unit in the forward direction. This pickup
threshold applies to zero-sequence or negative-sequence current based on the
NEG SEQ DIR OC1 TYPE
setting. When
specifying this setting, keep in mind that the design uses a positive-sequence restraint technique.
NEG SEQ DIR OC1 REV LIMIT ANGLE
— Defines a symmetrical limit angle (in both directions from the ECA) for the reverse
direction.
NEG SEQ DIR OC1 REV PICKUP
— Defines the pickup level for the overcurrent unit in the reverse direction. This pickup
threshold applies to zero-sequence or negative-sequence current based on the
NEG SEQ DIR OC1 TYPE
setting. When
selecting this setting, keep in mind that the design uses a positive-sequence restraint technique.
Figure 5-130: Negative-sequence directional OC1 logic
827091A7.CDR
AND
AND
AND
AND
AND
OR
OR
NOTE:
V_2 is negative-sequence voltage
I_2 is negative-sequence current
I_0 is zero-sequence current
AND
SETTING
Off = 0
Block
SETTING
= Neg Sequence
= Zero Sequence
Type
SETTINGS
Forward Pickup
RUN
( |3I_0| – × |I_1| ) Pickup K =
Positive-Sequence Restraint
TIMER
1.25 cycles
1.5 cycles
FLEXLOGIC OPERAND
NEG SEQ DIR OC1 FWD
SETTING
Enabled = 1
Function
ACTUAL VALUES
V_2
I_2
I_0
RUN
( |I_2| – × |I_1| ) Pickup K =
Voltage Polarization
SETTINGS
Forward ECA
RUN
Forward Limit Angle
Reverse Limit Angle
Offset
Forward
Reverse
SETTINGS
Reverse Pickup
RUN
( |I_2| – × |I_1| ) Pickup K =
Pos Seq Restraint
RUN
( |3I_0| – × |I_1| ) Pickup K =
AND
AND
AND
FLEXLOGIC OPERAND
NEG SEQ DIR OC1 REV