Computation Requirement Of Protection Functions - ABB REG316 4 Series Operating Instructions Manual

ABB Switzerland Ltd
3.1.2.2.

Computation requirement of protection functions

The amount of computation a protection function entails is de-
termined by the following:
complexity of the algorithms used which is characteristic for
·
each protection function.
Repetition rate:
·
The faster the operating time of a protection function, the
higher its repetition rate according to
tation requirement increases approximately in proportion to
the repetition rate.
Already active protection functions:
·
The protection system is able to utilise some of the inter-
mediate results (measured values) determined by a protection
function several times. Therefore additional stages belonging
to the same protection function and using the same inputs
generally only involve a little more computation for the
comparison with the pick-up setting, but not for conditioning
the input signal.
The computation requirement of the REG 316*4 protection func-
tions can be seen from
percentages in relation to the computing capacity of a fictitious
main processing unit.
According to
the functions increases for low settings of the time delay t and
therefore a factor of 2 or 4 has to be applied in some instances.
When entering the settings for a function with several stages, the
one with the shortest time delay is assumed to be the first stage.
REG 316*4 units equipped with a 316VC61a respectively
316VC61b processor module have a computing capacity of
250 %. This applies to all units having a local control and display
unit. Older units with a 316VC61 processor module only have a
computing capacity of 200 %.
The computing load can be viewed by selecting 'List Procedure
List' from the 'List Edit Parameters' menu and is given for the
four sets of parameters in per thousand. The greatest value in
the four sets of parameters determines the computing load.
3-6
REG 316*4 1MRB520049-Uen / Rev. F
Table 3.3. The values given are typical
Table 3.1, the computation requirement of some of
Table 3.1. The compu-