Day 8: Electricity Supply for Vital Services

For today... i go through the safety hand book and handouts given by my supervisor..

ELECTRICAL SUPPLY FOR VITAL SERVICES -SECURITY

The supplies is needed to maintain the operation to energise loads forming part of vital service. Other than that, this supplies must be uninterruptible (means not able to be interrupted by others e.g failure @ dis functioning) device... Normally it is UPS (Uninterruptible Power Supply)

Definition : What is UPS ??

A power supply that maintains power in the event of power failure.

Main functions :-

• Serve as a secure current power source to vital instrumentation
• Supply uninterrupted power to vital & essential loads for a specific period of time

This UPS could be divided into 2 parts :-

1. D.C
2. A.C

As per normal...D.C is a supply from battery. derived from battery-rectifier units (D.C UPS units) or from rectifier unit energised from one or more A.C uninterruptible...

Usually, this practice is used in small application.... small loads & closely integrated

A..C interruptible , maintained electricity supply.

This application actually used generators as a back up to produced electricity in power failure situation. As we known, big companies and organisation really particular involving the failure of their productions. For PETRONAS, in the duration of 5 minute power failure, they could loss almost billions of  Dollars. So it shows that, maintaining the current supply for the production to take place is  a very wise way to maintained their productions.

The backup generator that being used is either Diesel-based or Gas-based generator. The design operation is simple. The generator will automatically starts on the detection of mains power failures. Usually, this type of generator needs 10s -15s from idle to generates the currents.

The above diagrams actually shows the general flows of UPS. Main power is supplied through the UPS Block which consist of a switch and Battery. The switch could only acts as an ON/OFF switch. During the normal operation, the power directly empowered the loads through the switch. Once power failure occurs, the switch will trip or change the tipping from utility power to Battery. Thus, the fully charged battery will supply currents and backup the current failures. In the end, the load is still running with the help of the battery and on the other sides, production is still ON..

But this application also have many criteria to be taken into accounts. This will be later explained...(After i finished reviewing the UPS)..hahahahhahahahah