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The modern HSBC Headquarters building at Canary Wharf has introduced a new level of power supply reliability
into the industry.
The consultants Arup, and the builders CWCL, worked closely with Triplex Power Control Ltd to produce a
unique version of the proven Triplex power control system, used to access all sources of alternative power for
critical supplies in this building. Items encompassed by the system include generator starts/stops,
graduated generator loading, bus coupling, inhibiting of ATS units where required, and prioritised
allocation of available power.
In spite of the complexity of the electrical distribution requirements, the Triplex control system achieves a
level of reliability far in excess of that for a "normal" building by being inherently fault-tolerant,
which eliminates all potential single points of failure, such as faults in any component,
contact input, connection or control circuit power supply, and also includes for incorrect operation or
total failure of a PLC. Any fault that could occur, such as say a burnt out phase failure relay, is flagged up
as a warning, but does not affect operation, and can be corrected when convenient, and without any disturbance
to supplies.
During the exhaustive commissioning tests conducted by Commtech, the system has been proven and certificated
to operate 100% correctly with a comprehensive selection of faults imposed on it. The system is now fully
approved and in operation, and has won the full confidence of both the customer and the building operating
team.
"Downtime" of the control system over 3 years has been ZERO
1 Transformers. Power is supplied from two substations, which are themselves fed from different sources.
This power is fed to 14 transformers distributed within the building. All large LV panels are fed from two of
these transformers, one at each end, each transformer supplied from a different substation. In the event of
failure of supply from either transformer, that LV incomer is opened, and the buscoupler of the affected
switchboard is closed by the Triplex system.
2. Generators. The building incorporates five generators of 2.5MVA, operating at 415V. If any main
switchboard loses power from both transformers, or ATS units lose normal power, then generators are started
and connected as appropriate. Also if any generator failure or problem occurs when on load, then part of the
load is "dumped" whilst the reserve set is switched in to the correct section of the system, and this is then
started and connected. When the reserve power is established, the load is re-connected in stages to ensure the
load is gradually applied to the new set. All these operations are controlled by the Triplex system.
3. ATS units. There are some 32 Automatic transfer switches in the building. When these require generator
power, the Triplex system ensures by inhibiting the operation of selected switches that the load is connected
to the generator sets in stages as is necessary.
Because the system will continue to operate correctly with a fault present, that fault could remain unnoticed
unless a monitoring system is included to make operators aware that there is a problem. This is achieved by
ensuring that any differences that occur between the three channels are detected by a special monitor panel.
This panel receives information in various ways at HSBC, and displays and retains information regarding any
problems that may be present.
Special software has been developed that enables the Triplex system to over-ride a succession of faults
without problem.
All of the Triplex panels, and the associated touch screens, are powered by float-charged battery supplies.
In the case of failure of charge current for any reason, alarm contacts are operated, but the batteries can
continue to operate the system fully for 2 days without charge
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