Monitoring And Control Of 3-Tier Power Supply

Abstract

Reliable electricity supply is essential for development. As a result, demand for

electricity has continued to increase globally, occasioned by the fact that

electricity is highly portable and can be transformed from one form to another to

meet needs. In Nigeria and most developing countries, electricity supply from the

public utility is not only insufficient but highly erratic. The effect of this is adverse

on critical and sensitive infrastructure that depend on uninterrupted power

supply. Hence, many domestic, industrial and commercial consumers are

compelled to acquire one form of alternative source of power supply or another.

With this however, when different power schemes are interconnected, there

arises the challenge of switching between the power sources not only smoothly,

but in a manner that optimizes their use. Solving these challenges forms the focus

of this work. This design monitors three independent power sources: Utility Grid

of Power Holding Company of Nigeria (PHCN), solar and generator and engages

them following preset conditions in a microcontroller. A software program in

assembly language drives the microcontroller. Preference is given to the PHCN

line, but in the event of failure or abnormal conditions in the PHCN line, the

system will effect a changeover automatically to the solar source through

contactors, provided the output of the solar source is acceptable, else the system

will initiate the starting of the generator and transfer of load to same. This system

finds application wherever there is unreliable power supply and interconnected power schemes.

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