Limit the impact of the fault within the installation

In the event of a fault, the voltage of the installation is severely affected and risks causing a loss of loads. In particular, the management of faults related to short circuits within a critical installation using static transfer systems (STS) is particularly important.

To guarantee the continuity of the supply to their load, the STS must:

  • Operate autonomously
  • Be able to detect and differentiate a short-circuit downstream or upstream
  • Carry out a transfer of sources without overlap to avoid the propagation of the fault
  • Ensure the islanding of a short-circuited load

In the event of a short-circuit downstream of an STS, it must isolate the fault to prevent its propagation and alert the operator. The other STS connected to the same source must protect its load by immediately transferring it to an alternative source without propagating the fault.

Continuity
ANALYZE THE FAULT
BEFORE TRANSFER
Islanding
DO NOT PROPAGATE
THE FAULT
Example of a 2N installation

Case of a fault downstream of the STS

1 - Short-circuit on a load

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Example of a 2N installation

A short circuit appears on a load supplied by source B and induces a voltage disturbance on the distribution of source B.

2 - Islanding of the faulty load

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Example of a 2N installation

The local STS isolates the fault on source B by preventing its transfer. The other STS immediately transfer their load to source A without overlap.

3 - Loads protection

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Example of a 2N installation

The fault has been isolated on source B and the other loads are protected by source A.

Case of a fault upstream of the STS

For a fault upstream of the STS the fault isolation strategy consists of transferring all the loads to the healthy source without overlapping the sources.

1 - Fault upstream of the STS

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Example of a 2N installation

A fault occurs upstream of an STS supplied by source B causing a voltage disturbance on the distribution of source B.

2 - Transfer of loads to the healthy source

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Example of a 2N installation

The STS immediately transfer their load to source A without overlap.

3 - Loads protected

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Example of a 2N installation

The fault has been isolated on source B and the other loads are protected by source A.

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Socomec solution

STATYS Integrable Static Transfer Power Unit

The STATYS Integrable is a fully integrated Static Transfer Power Unit for integration into a cabinet or a power distribution unit (PDU). 

Supplied by two independent sources, STATYS Integrable increases the overall electrical infrastructure availability during abnormal events and programmed maintenance.