Power Quality

 Is there an international quality standard ISO 100001 for Quality of Power? Not yet. But quality of the important parameters of Power, namely, continuity of service, frequency, voltage, sinusoidal waveshape are to be within acceptable limits.

Tree limbs create a short circuit in electrical lines during a storm. This will result in a power outage around these lines

Continuity of Power:

1. momentory interruption (caused by transient faults)
2. temporary interruption (a bird getting burnt)
3. outage (sustained faults in Line/Station)
4. blackout (outage in a wider area, might take days to weeks to recover)

Voltage variations:

1. voltage dip/sag (momentary): rms voltage is below the nominal voltage - but within 10% drop
2. voltage swell: rms voltage is above the nominal voltage - but within 10% limit
3. flickering : rms voltage goes above & below the nominal repetitively in lights - but within 10% variation
4. undervoltage : rms voltage drop is below 10% of nominal voltage
5. brownout: term similar to undervoltage

Other notable power quality issues:

1. Under-frquency/ over-frequency
2. Harmonics - Total harmonic distortion (waveshape distortion caused by non-linear loads such as SMPS and CFLs)
3. Transients (by switching, lightning or network faults)

Harmonics: From a pure sine wave to square wave (click for animation)

Design of Electrical Installations

Lighting/ Illumination:
Types of light fixtures-
1. Incandescent lamps
2. Fluorescent lamps
3. Compact fluorescent lamps
4. Halogen lamps
5. High pressure mercury vapour lamps
6. Metal Halide lamps
6. Low pressure Sodium vapour lamps
7. Neon indicator lamps

Light pollution caused by high pressure sodium vapour lamps: courtesy - wikipedia

-Illumination level unit - Lux, Recommended lighting levels
-Color temperature - Warm white, cool white, daylight white
-Color rendering
-Ambient lighting & task lighting
-Illumination Simulation tools, e.g. Dialux

A colour temperature diagram

Power outlets/sockets:
Ratings - 5A, 13A, 15A

A typical 13A switched socket outlet

Terminals: L, N, E

Routing of power conductors:
1. Cable trench

A typical cable tray within a cable trench

2. Cable tray
3. Cable ladder

A typical cable tray in a form of ladder

4. Cable duct
5. Cable trunking

A typical cable trunking

Airconditioning & Ventilation:
1. Exhaust fans
2. Split type AC (Indoor & outdoor unit)
3. Package type AC
4. ACCU
5. PACU
6. AHU

Lightning protection and Earthing:
1. Earth rods
2. Earthing tape
3. Down conductors
4. No of Earthing points

Parts of a typical domestic lightning protection system

Telecommunication: 

 1. Internet

2. Telephone

RJ11 and RJ45 connectors - RJ means Registered Jack

3. IP TV

4. PABX

5. Satellite TV

Fire protection:

Types of Fire-

1. Paper/cloth/wood etc

2. Flammable liquids

3. Flammable gases

4. Electrical faults

Types of fire

Types of Extinguishers:

1. Water

2. Foam

3. CO2

A typical CO2 fire extinguisher

4. Dry chemical powder

5. Wet chemical powder

6. Sand buckets

Fire detection:

1. Heat detectors

2. Smoke detectors - Infrared

3. Smoke detectors - Photoelectric

A typical smoke detector installed on the ceiling

4. Duct detectors

5. Manual call points

6. Emergency fire exit and gathering (meeting) points