ABB Relion 670 Series Applications Manual page 164

Section 7
Current protection
7.2.1 Function revision history
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revision
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7.2.2 Identification
Function description
Four step single phase overcurrent
protection
7.2.3 Application
The Four step single phase overcurrent protection(PH4SPTOC, 51) function is used in several
applications in the power system. Some applications are:
• Short circuit protection of feeders in distribution and subtransmission systems. Normally these
feeders have radial structure.
• Back-up short circuit protection of transmission lines.
• Back-up short circuit protection of power transformers
• Short circuit protection of different kinds of equipment connected to the power system such as; shunt
capacitor banks, shunt reactors, motors and others.
• Back-up short circuit protection of power generators.
The single phase overcurrent protection is used in IEDs having only input from one phase, for example
busbar protection for large busbars (with many bays).
In many applications several steps with different current pick up levels and time delays are needed.
PH4SPTOC(51) can have up to four different, individual settable, steps. The flexibility of each step of
PH4SPTOC(51) function is great. The following options are possible:
Choice of delay time characteristics: There are several types of time delay characteristics available such
as definite time delay and different types of inverse time delay characteristics. The selectivity between
different overcurrent protections is normally enabled by co-ordination between the function time delays of
the different protections. To enable optimal co-ordination all overcurrent IEDs, to be co-ordinated against
each other, should have the same time delay characteristic. Therefore a wide range of standardised
158
Product History
revision
2.2.1 -
2.2.1 -
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2.2.4 -
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2.2.4 -
2.2.5 The harmonic restraint function changed to freeze the definite and IDMT timers.
IEC 61850
identification
PH4SPTOC
© 2017 - 2021 Hitachi Power Grids. All rights reserved
IEC 60617 ANSI/IEEE C37.2
identification device number
51
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4
alt
4
OC V1 EN-US
1MRK 505 370-UUS Rev. K
GUID-94DB6C52-230F-4313-B6EE-1D8A1640C292 v1
SEMOD127810-2 v2
SEMOD127937-4 v2
Busbar protection REB670
Application manual