ECE464 Power Electronics Engineering Assignments Solution

ECE464 Power Electronics Engineering Assignments Solution

ECE464 Power Electronics Engineering Assignments Solution

Shops 1-5 max cable runs for final sub-circuits

Fluorescent fittings

20 meters

Exit lights

20 meters

Light points

20 meters

Exhaust fans

20 meters

10a socket outlets

24 meters

15a socket outlets

21 meters

20a 3 phase outlet

14 meters

25a 3 phase a/c

18 meters

Instantaneous HWS

16 meters

Storage HWS

19 meters

1. Max demand is required for each shop separately. Show all workings
2. Max demand is required for all shops combined
3. Consumer mains are to be buried enclosed in ground. Sub mains are to be run in roof space, enclosed on cable tray. You are to calculate size and volt drops of all circuits (ref AS/NZS 3000-AS/NZS 3008.1.1. Calculate all earth conductor sizes and check for and apply if applicable any de-rating factors
4. Main switchboard multiple master meter enclosure:

A. Design and detail using AZ/NZS 3000 and WA Electrical Requirements

B. Draw a single line diagram, protection devices, A/links (if any), N links, earth link, n-link, main earth, earth bonds and all conductor sizes.

Solution

The circuit connection requires that the neutral connection and the conductors are continuous and connected by splicing and bonding conductor. Connect the ends using the soldering method or with connector and tapping. There are other research methods used in electrical circuit connection such as T joints with a metal enclosure. There are 5 shop units which are supplied with underground power and they have multiple masters metered. The circuit loading, the numbers of final sub-circuits and many other specifications have been left out deliberately. The table below analyzes the components of the electrical design of the shops.

1. Max demand is required for each shop separately. Show all workings
2. Max demand is required for all shops combined
3. Consumer mains are to be buried enclosed in ground. Sub mains are to be run in roof space, enclosed on cable tray. You are to calculate size and volt drops of all circuits (ref AS/NZS 3000-AS/NZS 3008.1.1. Calculate all earth conductor sizes and check for and apply if applicable any de-rating factors
4. Main switchboard multiple master meter enclosure:

A. Design and detail using AZ/NZS 3000 and WA Electrical Requirements

B. Draw a single line diagram, protection devices, A/links (if any), N links, earth link, n-link, main earth, earth bonds and all conductor sizes.

Solution

The circuit connection requires that the neutral connection and the conductors are continuous and connected by splicing and bonding conductor. Connect the ends using the soldering method or with connector and tapping. There are other methods used in electrical circuit connection such as T joints with a metal enclosure. There are 5 shop units which are supplied with underground power and they have multiple masters metered. The circuit loading, the numbers of final sub-circuits and many other specifications have been left out deliberately. The table below analyzes the components of the electrical design of the shops

Part 1: Sub-main Cables

 

Individual Shop Max Demand #1 -#5

LOAD GROUP

LOAD

REMARKS

BALANCE

CALCULATIONS

CONTRIBUTIONS PER PHASE

 

 

 

R

W

B

 

R

W

B

B11

Double 10A socket outlets

8

8

8

7.8

7.8

7.8

B11

Single 10A socket outlets

Single calculation on double socket

1

1

1

Place with double

 

 

 

B11

Single 15A socket outlets, 1 phase

Single calculation on double socket

3

3

3

Place with double

 

 

 

B11

20 A 3 phase socket outlet

[20A+75% REM AID

1

2

1

=50

50

50

50

C

25A 3 phase air conditioning unit

AIC 75% ON 1-phase

 

 

1

 

 

18.2

C

15A 3 phase instantaneous HWS

HWS 100% 4IGEST

1

1

1

R 100%, W 100%, B75%

15

15

11.2

A

20A storage HWS, 1 phase

FLC

 

1

1

1

R 100%, W 100%, B75%

15

15

11.2

A

Twin 36 w fluorescent fittings

FLC

9

 

 

9*0.42A=3.78A

3.78

 

 

A

20 W exit lights

FLC

 

2

 

2*100/230 =0.86A

 

 

0.86

A

Tube 36W fluorescent fittings

FLC

 

 

4

4*0.42 A = 1.68A

 

 

1.68

A

Light points

FLC

 

4

4

 

 

3.6

3.6

A

Exhaust fans at 0.25a fan

FLC

 

2

2

0.25*3.45*2

 

0.86

0.86

Max Demand

91.58

92.26

105.4

Part 2&3: Mains Cable & Cable Selection

CONSUMPTION FOR ALL SHOPS COMBINED

MAXIMUM DEMAND

TABLE

ITEM

TABLE

COLUMN

CABLE SIZE/CCC

DE-RATING

96.413 A

T3(4)

2

7

24

35mm2 / 122 A

50mm2/ 144 A

N/A

N/A

Voltage Drop

4V

Table/Column

41/6

50mm2

Vc =0.219 mV/mA

Calculation

Cable Size

Co-ordination

Part 4: Earth sizes- Fault current Performance

Shop Fault Level Demand #1- #5

Sub-Mains Impedance (Zt)

Current Fault

Table: 30/30

Column: 3/2

Main Switch

Type

Voltage

Amperage

kA rating

Hager HHA125U

C

415 (3-phase)

125A

25kA

Running Earth

Size

25mm2

Clause

5 5 3 5

Structural Bond

Size

25mm2

Clause

5 5 3 3 2

Switchboard Bond

Size

25mm2

Clause

5 5 3 3 2

Water Bond

Size

4mm2

Clause

5 8 3 2


Part 5: Main switchboard, multiple master meter enclosure and unit sub-boards

In a nutshell, the AS3000/ANZ standards are adopted in Australia and New Zealand to regulate the building and electrical wiring for different types of buildings. The standards are given load codes which govern the length and diameter of cables used especially in earthing and underground cabling. The standards, specify, further the kind of insulation that is appropriate for the cables used to ensure losses are minimized.

References

1. AS3000/NZ1 (2007) Wiring Rules and Standards: Electrical Installations (known as the Australian/New Zealand Wiring Rules). Standards, Australia.