4.7.1.7
Application
DSTPDIS provides a fast and reliable protection for overhead lines and power cables.
The function is applied in distribution and sub-transmission networks where three-
phase tripping is allowed for all kinds of faults.
Figure 556: Application scope of DSTPDIS
Typically these networks are operated in ring or meshed type configurations. The
switching state of these networks is changed frequently due to daily operation
and load flow considerations. The networks also include varying capacities of
distributed generation which makes it impossible to apply simple overcurrent-
based schemes. In these networks, DSTPDIS is used to provide a fast and selective
protection for overhead lines and power cables. It can also be applied for radial
feeders to increase the sensitivity of the protection, especially if the short circuit
power of the source is low or it changes due to network operation.
From the selectivity point of view, it is advantageous that in the protection chain
all functions in different positions operate according to the same measuring
principle. Therefore, DSTPDIS can also be applied for the backup protection of
main transformers and buses. This way, selectivity in the distance protection of
the outgoing lines is easier to achieve.
Figure 557: Typical network configurations for DSTPDIS application
1MRS759142 F
Protection functions
REX640
Technical Manual
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