GE L90 Instruction Manual page 474

GROUPED ELEMENTS
POWER SWING MODE
power swing blocking and out-of-step tripping functions. The three-step mode applies if there is enough space between
the maximum load impedances and distance characteristics of the relay that all three (outer, middle, and inner)
characteristics can be placed between the load and the distance characteristics. Whether the spans between the outer
and middle as well as the middle and inner characteristics are sufficient is determined by analysis of the fastest power
swings expected in correlation with settings of the power swing timers.
The two-step mode uses only the outer and inner characteristics for both blocking and tripping functions. This leaves more
space in heavily loaded systems to place two power swing characteristics between the distance characteristics and the
maximum load, but allows for only one determination of the impedance trajectory.
POWER SWING SUPV
supervision responds to the positive-sequence current.
POWER SW I2 SUPV ENAB
detect the presence of significant unbalance in current signals, such as during fault conditions. Under these conditions, the
POWER SWING BLOCK
POWER SWING I2 SUPV
POWER SWING FWD REACH
quadrilateral characteristic. For a simple system consisting of a line and two equivalent sources, this reach needs to be
higher than the sum of the line and remote source positive-sequence impedances. Detailed transient stability studies can
be needed for complex systems in order to determine this setting. The angle of this reach impedance is specified by the
POWER SWING FWD RCA
POWER SWING QUAD FWD REACH MID
The angle of this reach impedance is specified by the
setting is "Mho."
5
POWER SWING QUAD FWD REACH OUT
The angle of this reach impedance is specified by the
setting is "Mho."
POWER SWING FWD RCA
angles of all blinders, and both forward and reverse reach impedances of the quadrilateral characteristics.
POWER SWING REV REACH
quadrilateral characteristic. For a simple system of a line and two equivalent sources, this reach needs to be higher than
the positive-sequence impedance of the local source. Detailed transient stability studies can be needed for complex
systems to determine this setting. The angle of this reach impedance is specified by the
"Mho," and the
POWER SWING FWD RCA
POWER SWING QUAD REV REACH MID
The angle of this reach impedance is specified by the
setting is "Mho."
POWER SWING QUAD REV REACH OUT
angle of this reach impedance is specified by the
setting is "Mho."
POWER SWING REV RCA
setting applies to mho shapes only.
POWER SWING OUTER LIMIT ANGLE
the power swing detect mho operating characteristic diagram are to be observed: values greater than 90° result in an
apple-shaped characteristic; values less than 90° result in a lens-shaped characteristic. This angle must be selected in
consideration of the maximum expected load. If the maximum load angle is known, coordinate the outer limit angle with a
20° security margin. Detailed studies can be needed for complex systems to determine this setting. This setting applies to
mho shapes only.
POWER SWING MIDDLE LIMIT ANGLE
for the three-step mode. A typical value is close to the average of the outer and inner limit angles. This setting applies to
mho shapes only.
5-250
— This setting selects between the two-step and three-step operating modes and applies it to both
— A common overcurrent pickup level supervises all three power swing characteristics. The
— This setting is to enable I2 supervision logic through a FlexLogic operand, which is used to
operand is not asserted.
— This setting specifies the threshold of the I2 supervision logic.
— This setting specifies the forward reach of all three mho characteristics and the inner
setting.
— This setting specifies the forward reach of the middle quadrilateral characteristic.
— This setting specifies the forward reach of the outer quadrilateral characteristic.
— This setting specifies the angle of the forward reach impedance for the mho characteristics,
— This setting specifies the reverse reach of all three mho characteristics and the inner
setting for inner "Quad."
— This setting specifies the reverse reach of the middle quadrilateral characteristic.
— This setting specifies the reverse reach of the outer quadrilateral characteristic. The
— This setting specifies the angle of the reverse reach impedance for the mho characteristics. This
— This setting defines the outer power swing characteristic. The convention depicted in
— This setting defines the middle power swing detect characteristic. It is relevant only
setting. The setting is not used if the shape
POWER SWING FWD RCA
setting. The setting is not used if the shape
POWER SWING FWD RCA
setting. The setting is not used if the shape
POWER SWING FWD RCA
setting. The setting is not used if the shape
POWER SWING FWD RCA
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
setting for
POWER SWING REV RCA