ABB Relion 670 Series Applications Manual page 122

Section 7
Impedance protection
example a stable case with synchronism retained), the function is as well reset, which includes
the pickup output signal (PICKUP), which is reset to 0 (FALSE) after
elapsed. However, the measurements of analogue quantities such as R, X, P, Q, and so on
continue without interruptions. Recommended setting of
seconds.
NoOfSlipsZ1 : Maximum number of pole slips with centre of electromechanical oscillation
•
within zone 1 required for a trip. Usually,
NoOfSlipsZ2 : Maximum number of pole slips with centre of electromechanical oscillation
•
within zone 2 required for a trip. The reason for the existence of two zones of operation is
selectivity, required particularly for successful islanding. If there are several pole slip (out-of-
step) relays in the power system, then selectivity between relays is obtained by the relay reach
(for example zone 1) rather then by time grading. In a system, as in Table 12, the number of
allowed pole slips in zone 2 can be the same as in zone 1. Recommended value:
2 or 3 .
Operation : With the setting Operation OOSPPAM function can be set On/Off .
•
OperationZ1 : Operation zone 1 Enabled , Disabled . If OperationZ1 = Disabled , all pole-slips with
•
centre of the electromagnetic oscillation within zone 1 are ignored. Default setting =
More likely to be used is the option to extend zone 1 so that zone 1 even covers zone 2. This
feature is activated by the input to extend the zone 1 (EXTZ1).
OperationZ2 : Operation zone 2 Enabled , Disabled . If OperationZ1 = Disabled , all pole-slips with
•
centre of the electromagnetic oscillation within zone 2 are ignored. Default setting =
• tBreaker : Circuit breaker opening time. Use the default value tBreaker = 0.000 s if unknown. If
the value is known, then a value higher than 0.000 is specified, for example
the out-of-step function gives a trip command approximately 0.040 seconds before the
currents reach their minimum value. This in order to decrease the stress imposed to the
circuit breaker.
VBase : This is the voltage at the point where the Out-of-step protection is installed. If the
•
protection is installed on the generator output terminals, then
phase to phase voltage of the protected generator. All the resistances and reactances are
measured and displayed referred to voltage
ReverseR , and ForwardR must be given referred to VBase. IBase is the protected generator
nominal (rated) current, if the Out-of-step protection belongs to a generator protection
scheme.
InvertCTCurr : If the currents fed to the Out-of-step protection are measured on the protected
•
generator neutral side (LV-side) then inversion is not necessary (
provided that the CT's orientation complies with ABB recommendations, as shown in Table 12.
If the currents fed to the Out-of-step protection are measured on the protected generator
output terminals side (HV-side), then invertion is necessary (
provided that the CT's actual direction complies with ABB recommendations, as shown in
Table 12.
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tReset is in the range of 6 to 12
NoOfSlipsZ1 = 1 .
VBase is the nominal (rated)
VBase . Observe that ReverseX , ForwardX ,
InvertCTCurr = Enabled ),
1MRK 511 407-UUS Rev. J
tReset interval of time has
NoOfSlipsZ2 =
Enabled .
Enabled .
tBreaker = 0.040 s :
InvertCTCurr = Disabled ),
Phasor measurement unit RES670
Application manual