Case Study- The facility engineer maintaining a 6 story office building at Beach road, Singapore

Case Study:

You are the facility engineer maintaining a 6 story office building at Beach road. The building is 20 years old; the infrastructure of the building is not maintained well and facing wear and tear. The majority of the parts have passed their service lifespan.

The building has been experiencing many complaints and the following are some critical issues that are frustrating tenants. Some of them are delaying rental payments and will leave the building when the lease expired

a. Power interruption frequently between 2 pm to 4 pm caused by overcurrent tripping in the LT switchboard. ACMV chillers are connected to the MSB
b. Lift man trap due to power failure caused by earth leakage
c. Emergency backup power does not provide sufficient coverage for all the IT system causing a shutdown and loss of data during a power surge or interruption
d. False fire alarm during heavy rain and lightning. Later found that control card burnt
e. Utility bills from TUAS power to your building has a surcharge of $900 per month for KVAR

The property owner blames your team for the poor maintenance of the system in the last few years and might sue your company for negligence.

Your manager instructed you to review your electrical system condition urgently and make a recommendation report to the owner to defend your company and to improve the reliability of the electrical system.

The report shall have an overall evaluation of the Single Line drawing to highlight the following gaps and provide an explanation of the issues and provide remedial action.

•  Protection relays erratic performance and remedial action
• Emergency power backup not meeting the requirements.
•  Electronic cards damaged by high voltage; cause and remedial.
• Utility KVAR surcharges cause and elimination proposal.
• Updating of the single line drawing with proper description
• The final recommendation in implementing proper maintenance to eliminate the above incidents.

Summary of Condition

Refer to the single line provided

1. Description of the assets: 20 yrs. old building with 20 yrs. old assets
2. Age of the assets: HT / LT switchboard is 20 yrs. old with no upgrading
3. Condition / Situation of the assets/ equipment: Protection relays; Protection relay such as ELCB / RCCB / OC / OL / under voltage relay, are old obsolete beyond repair.
4. The subject of observation: Nuisance tripping experience recently or failure to trip or inaccurate tripping during the annual testing, etc.
5. Findings: Protection relay such as ELCB / RCCB / OC / OL / under voltage relay all has a life span of 10 years of effective operation life span. More than that the items are likely to perform erratically and inaccurately.

Propose a single line drawing for the sub-distribution board to show how the various equipment in a Datacenter; should be provided power supply with; including the UPS back up support.

•  3 nos of air-con unit each having 20KW on 415V
•  3 nos of the isolator with 10KW output at 415V
• 30 nos of 230V AC power socket outlet with resistive load 20.
•  Calculate the total power required
• Proposed Single Line drawing with proposed protection ratings showing the
  UPS connection clearly.