Setting The Characteristic Angle; Setting The Basic Time (T Basic ); Circuit-Breaker Delay; Comparison Time - ABB RELION REB500 Technical Manual

Section 5
Bay protection functions
• U : 100 V or 200 V according to VT unit in use
N
• Usec.asymm: voltage component 3U
(for example, VT errors)
• V-Setting: setting of the enabling voltage for the directional measurement
5.9.6.5

Setting the characteristic angle

The line marking the reversal of direction lies at ±90° in relation to the reference voltage.
To achieve symmetrical operation of the directional element in spite of this, the characteristic
angle should be equal that of the zero-sequence impedance of the source.
5.9.6.6 Setting the basic time (t
The basic time is the period between pick-up of the protection and the earliest possible trip.
The operation of the protection function can be coordinated with others on the same line by
judiciously setting the basic time.
The basic time is also used to achieve coordination between the ground fault function (three-
phase tripping) and the distance function (phase-selective tripping). The ground fault
protection is delayed to allow time for the distance protection to respond to a fault if it is
possible.
The basic time is normally set to:
t >
Basic
The sum of these times is usually about 100 to 200 ms.
5.9.6.7

Circuit-breaker delay

To avoid operation of the enabling current detector during the transient oscillations, which
occur following the closing of the circuit-breaker, it is blocked for 50 ms upon receiving the
corresponding signal from the CB.
5.9.6.8

Comparison time

The comparison time is the time allowed for the directional comparison to be made and is
therefore dependent on the type of transfer tripping scheme.
The comparison time has a fixed setting of 1 s.
5.9.6.9 Setting the wait time (t
The waiting time is also started at the end of the basic time, but is only effective in a blocking
scheme.
166
)
Basic
max. tripping time of the phase-selective distance protection (taking account of signal
transmission time and sequential tripping)
+ CB operating time
+ aux. contact time (input CB closed)
+ safety margin
)
Wait
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caused by asymmetries in the VT secondary circuit
0
1MRK 505 406-UEN B
GUID-D6147D84-E5FB-4E1F-B114-0F4C7864946E v1
GUID-531CDD9D-C567-43B4-946F-31C9348D726C v1
GUID-0F4DD3FD-FE64-4784-BA07-69EFF6C0C9F8 v1
GUID-32875FF0-D8CE-4860-BD15-09FAB2469AF8 v1
GUID-CA14249E-57B2-4E96-A6C9-BD2D0FB9F99C v1
Bay protection functions REB500
Technical manual