electrical design guideline steps maria c. gonzalez

ELECTRICAL DESIGNGUIDELINE STEPS

Maria C. Gonzalez

ELECTRICAL DESIGN STEPS

• 1.What equipment do you want to install?

• 2. How do we install it?– Power requirements: conductor size– Communications requirements

• 3. Cost

ELECTRICAL EQUIPMENT

ELECTRICAL PLAN

POWER REQUIREMENTS

• STEPS:

• 1. Find the total load in Watts for the electrical equipment you want to install.

• 2. Calculate the current

• 3. Calculate the conductor size

POWER REQUIREMENTS

• CALCULATIONS:

• 1. Total Wattage

• 2. Calculate the current knowing the total wattage W:

VvoltageV

factorpowerPF

wattsW

VPF

WAI

WWW

T

T

120;

8.0;

;

)().()(

....21

CONDUCTOR SIZE• Using Ohm’s Law, find R

• Resistance per unit length km =

• voltage drop is 5% of 120V or 6 v

• D; distance in Km from PG&E pole to service cabinet

)(

)()(

R

VdropVoltageAI

D

R

2

CONDUCTOR SIZE TABLE Resistance /km Size AWG Ampacity*

10.07 14 206.33 12 253.97 10 352.55 8 501.60 6 651.01 4 850.82 3 1000.62 2 1150.49 1 1300.38 1/0 1500.31 2/0 175

ELECTRICAL ELEMENTS 1 POWER AND COST

ITEM LOCATION/USE $COST WATTS

Lighting ramp, bridge 100 310

Traffic Signal ramp, toll bridge 500 150

Traffic Sensor:

Everywhere. To gather traffic information: speed, # vehicles

-A). loop wire 600/lane 50

-B) radar 800/all 10

- C)TV camera

1000/all 50

ELECTRICAL ELEMENTS 1Communications

ITEM COMMUNICATIONS FROM DEVICE TO CONTROLLER

COMMUNICATIONS FROM CONTROLLER TO TMC

Lighting

Traffic Signal

Traffic Sensor:

Twisted pair (telephone), fiber optic, wireless

- A)loop wire Loop wire

- B) radar Twisted pair

- C) TV camera

coaxial cable

ELECTRICAL ELEMENTS 2 POWER AND COST

ITEM LOCATION/USE

$COST WATTS

DRIVERAIDS:- Sign Near main

intercrosses46000 17000

- Radio(HAR)

Everywhere,mountain

3000 50

- Callboxes

everywhere 300 10

ELECTRICAL ELEMENTS 2Communications

ITEM COMMUNICATIONS FROM CONTROLLER TO DEVICE

COMMUNICATIONS FROM CONTROLLER TO TMC

DRIVER AIDS:

- Sign twisted pair(telephone outlet)

Twisted pair (telephone), fiberoptic, wireless

- Radio (HAR)

Coaxial to antenna, Twisted pair (telephone), fiberoptic, wireless

- Call boxes

Twisted pair (telephone), or wireless

Twisted pair (telephone), fiberoptic, wireless

ADDITIONAL ELECTRICAL ELEMENTS COST

ITEM USE $ COST

Pole Traffic signal, lighting, TV

2000

Power cabinet To connect with PG&E 3000

Controller Talk with sensors andDriver aids

10,000

Cable:

- loop wire 1.00/m

- coaxial 0.66/m

- Twisted pair 1.20/m

- Fiberoptics 10.0/m

- Power conductor 0.66/m

Conduit One for power, one forcommunications

2.27/m

COMMUNICATIONS APPLICATION BANDWITH

REQUIREMENTS APPLICATION BANDWIDTH

Traffic data very low

Voice low

Real time traffic data high

Video high

High definition video very high

COMMUNICATIONS TECHNOLOGY BANDWIDTH

TECHNOLOGY MEDIUM

BANDWIDTH REPEATER AT (m):

Twisted pair low 600

coaxial high 150

fiber very high 110,000

Cellular Radio (MHz)

medium 2000-16000

Microwave (GHz)

highest Line of sight