Office Building Solution

BU I LDI NG SOLUT IONS

12

— Scheme

— Simple radial scheme

— Double radial scheme

In a simple radial scheme, the power is derived from a system of main busbars, from which the energy is then distributed radially to individual consumers or secondary busbar systems. The simple radial scheme has the following advantages: • Minimum material and installation costs; • extreme simplicity in the operation of the plant (operations, maintenance). On the other hand, the simple radial scheme has the following disadvantages: • a failure in any point of the system starting from the supply point causes the total outage of the downstream elements; • a failure on the power supply or on the main busbars causes total out of order of the plant; • no flexibility in case of maintenance, checks, modifications, expansions because of the impossibility to temporarily put an element of the plant out of service, without this implying the shutdown of a part or, at the limit, of the whole plant.

The double radial scheme basically consists of the combination of two simple radial systems, which from upstream to downstream extend associated with each other.

The double radial scheme has the following advantages: • The out-of-service of one element of the system does not cause the downstream elements to be completely out-of-service; • Flexibility in case of maintenance, verifications, modifications, expansions, since it is possible to temporarily put an element of the system out of service, without stopping a part or, at the limit, the whole system. On the other hand, the double radial scheme involves the following disadvantages: • Cost of materials and installation; • more complex plant operation (operations, maintenance). The duplication of system components can be extended to a single user, or, more frequently, to one or more distribution nodes. Redundancy must be achieved not only with respect to the power components but also with respect to the components of a possible command and control system. In a double radial scheme all distribution boards are equipped with two sections of busbars separated by a switch (junction), which can be open or closed army.

Example of simple radial diagram

Example of double radial diagram

Power supply 1

Power supply 2

It is therefore clear that, if higher levels of reliability are to be achieved (which is desirable if a dual radial distribution system is to be set up), an alternative power source characterized by a much higher level of reliability than that considered must be provided, such as, for example, a generator set or static uninterruptible power supply system.

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