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Higher ratings through energy-efficient cooling

SIVACON S8 – cubicle in circuit-breaker design and in universal mounting design with forced cooling

Your benefit

  • Cubicle in circuit-breaker design and in universal mounting design with increased rated current due to forced cooling

  • Reduced derating of integrated components

  • High operational safety thanks to controlled and monitored cooling system with redundant fans

  • Safety for personnel and switchboard by means of tests according to IEC 61439-2

  • High personnel and switch- board safety in case of arcing by means of tests under conditions of arcing according to IEC/TR 61641

Safe and reliable power distribution

Low-voltage switchboards are subject to continuously increasing technical requirements with high demands for personnel and operational safety. This is manifested by a further increase in packing density associated with a high degree of protection for the switchboard and a high form of internal separation. The rated currents in the switchboard increase. As a consequence, the higher operational power loss results in a higher development of heat where more power is required in confined spaces, for example, in incoming feeder cubicles and in the compact withdrawable design.

 

The higher temperature rise leads to a derating at the installed components and can have an influence on the service life of sensitive electronic devices. Relief is provided by different measures such as enlarged busbar cross-sections.

To improve the heat dissipation and cooling, cubicle dimensions can be increased or the degree of protection and the form of internal separation reduced as an alternative. However, these measures no longer satisfy the current demands placed on low-voltage switchboards, which means that higher ratings of the devices must be enabled by means of energy-efficient cooling.

The reliable way to more cost-efficiency
SIVACON S8 offers the possibility to equip cubicles in circuit-breaker design and in universal mounting design with forced cooling. The targeted use of fans will considerably reduce the device derating caused by operational power loss. This allows to increase the rated current without costly expansions or enlargements of the switchboards. Cubicle properties such as a high degree of protection and a high form of internal separation are not restricted thereby.

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Temperature rise in circuit-breaker cubicle without forced cooling

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Cooling system with fans underneath the 3WL circuit breaker

Innovative solution

SIVACON S8 offers a patented forced cooling technology for cubicles in circuit-breaker design and in universal mounting design. The system was designed and optimised by Computational Fluid Dynamics (CFD) simulation, and was confirmed by numerous design verifications according to IEC 61439-2. It reduces the derating and provides a low temperature profile inside a cubicle to ensure safe and long life operation of sensitive electronic equipment. The control system monitors the temperature at critical spots, ensuring energy-efficient cooling at any time. To increase the service life of the fans, these are speed-controlled according to the temperature development. Moreover, the system has been designed redundantly.

Technical features

  • Optimally dimensioned cooling system

  • Effective cooling directly at the required positions

  • Three or four temperature-controlled, variable-speed fans

  • Factory-set control, no further settings required

  • Degree of protection possible up to IP54

  • Internal separation possible up to form 4

  • No restrictions for installation of devices

  • No space restrictions in the connection compartment

  • Safety for personnel and switch- board by means of tests according to IEC 61439-2

  • High level of safety for personnel and switchboard in case of arcing thanks to testing under conditions of arcing in accordance with IEC/TR 61641

Functional principle

  • Cooling of the limiting measuring points determined in temperature-rise tests

  • Improved heat dissipation thanks to additional heat sinks and a boosted, directional airflow using fans and air ducts (forced convection)

Security of operation

  • Three or four controlled, monitored fans

  • Redundant safety concept

  • Failure of one fan has no effect on the rated current of the cubicle

  • Emergency operation is possible should the complete cooling system fail

  • An alarm is output when a fan fails and/or if an impermissible temperature rise occurs

  • Factory-set fan control without further settings (incorrect parameterisation impossible)

  • Control voltage from power system (failure only possible with interruption in line voltage)

  • Use of long-life quality fans

  • Temperature-controlled low fan speed increases the service life

Maintenance

All measures are incorporated in the maintenance concept for the switch- board. For checking and cleaning of fans and filter pads:

  • No change required regarding inspection intervals

  • Easy accessibility for maintenance and repair

  • Fan replacement possible during operation

  • Spare parts available

Other components of the cooling system are maintenance-free.

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Forced cooling for circuit-breaker design

Your advantages

Reduction in derating

As a result of forced cooling with fans, the rated current of cubicles in circuit-breaker design and in universal mounting design can be increased. This is possible without additional costs for larger busbar cross-sections or a circuit breaker with a larger type of construction in the cubicle in circuit-breaker design. Further demands placed on the switchboard such as a high degree of protection or a high form of internal separation are not restricted by the forced cooling. The low temperature profile inside a MCC enables safe and long-life operation of sensitive electronic equipment.

Safety thanks to redundant cooling system
The monitored cooling system of redundant design provides high operational safety. Cubicles with forced cooling in circuit-breaker design and in universal mounting design are completely integrated into the SIVACON S8 low-voltage switchboard. Design veri- fications with tests in accordance with IEC 61439-2 and testing under conditions of arcing in accordance with IEC/TR 61641 provide a high level of safety for personnel and switchboard.

Safe and user-friendly

For high personnel safety, in the case of the 3WL air circuit breaker in withdrawable design, moving to the connected, test, or disconnected position takes place with the door closed. The cubicle dimensions are tailored to the size of the circuit breakers. The circuit-breaker design provides optimum connection conditions for every rated current range. As an alternative to cable connections, the system also includes design verified connections to the SIVACON 8PS busbar trunking systems. The busbar trunking system connection units, specially developed for SIVACON S8, are an integral component of the cubicles in circuit-breaker design. Withdrawable units of all sizes in universal mounting design are equipped with integrated operating error protection and a uniform, clear indication of the withdrawable unit positions. Here, moving to the test, disconnected, or connected position also takes place with the door closed and without eliminating the degree of protection.