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What is IEEE-738?
IEEE-738 is a widely used and accepted method of calculating the ampacity (thermal rating) of transmission conductors under specified weather conditions. Conductor parameters and major weather conditions are input into the method. Major weather conditions affecting rating include air temperature, wind speed/direction, and solar input, although there are some other minor effects. Both steady-state and short-duration ratings can be calculated.
IEEE-738 is based on both experimental data and theoretical equations. The full name of the standard is, "IEEE Standard for Calculating the Current-Temperature Relationship of Bare Overhead Conductors". The standard may be purchased from IEEE (Institute of Electrical and Electronics Engineers, Inc.) at
How to Calculate a Thermal Rating
An equation to calculate conductor rating is developed by first recognizing that the total input heat (per unit length) to a conductor must equal the total output heat in the steady state. The conductor is heated by ohmic losses (I2R) and solar input, and it is cooled by convection and radiation.
The following equation and figure shows this main "heat balance":
Qsolar + I2R = Qconvection + Qradiation
where
- Qsolar is the heat input due to solar radiation, W/ft
- I2R is the heat input due to line current, W/ft (R is a function of conductor temperature)
- Qconvection is the heat output due to convection (a function of wind, air temp, conductor temp), W/ft
- Qradiation is the heat output due to radiation (a function of air temp and conductor temp), W/ft
Heating and Cooling of an Overhead Conductor
Now, the equation can be reworked to solve for current as a function of the weather conditions. The Qconvection, Qradiation, Qsolar, and R terms are all functions of weather conditions and of conductor temperature. If the weather conditions are measured and the conductor temperature is set to the maximum allowable conductor temperature,the calculated current is the rating current as shown in the following equation.
What else can I help you with?
What is the ampacity of gold silver copper and aluminum?
The ampacity for copper is 1000A per square inch, in some places is 700A psi.
What is the line loss of 4 ACSR when the voltage is 14400 volts?
It doesn't really matter what the distribution voltage is. Line loss is dependant on the current through the conductor. #4 ACSR (aluminum conductor, steel reinforced, used in electrical transmission), has a typical resistance of 0.399 ohms per 1000 feet, and a maximum ampacity of 140. At max load, the I^2 * R loss would be about 7.82kW per 1000 feet of cable, or about 123kW per mile of 3-phase distribution. A 14,400 volt 140A system delivers about 3.48MW at unity power factor, so this represents about a 3.5% loss per mile, which is why 14.4kV is used for distribution, not transmission. Most likely, the cable would reach thermal limit well before 140A, and so would never be loaded to the max ampacity, so this is the theoretical max. At a more reasonable current, line loss would be correspondingly less.
What size copper grounding electrode conductor is required for a service that has three sets of 600 kc mil copper conductors per phase?
The grounding conductor of a service distribution is sized by the ampacity of the service. By just stating the wire size, this does not give this information, as many variables enter into what wires are used depending on length, ambient temperature and insulation factor to name a few.
Weight of copper wire?
(8) GAUGE WIRE 50lbs per 1000ft or 1lb per 20ft (12) GAUGE WIRE 19lbs per 1000ft or 1.9lbs per 100ft (14) GAUGE WIRE 12lbs per 1000ft or 1.2lbs per 100ft
How much do electrician make per hour?
It Varies, Here in the Northeast, in NH it can be as low as $23 per hour to about $65 per hour if your self employed. If your working for a company or for your apprentiship you can expect as low as $8 per hour to $30 per hour. In NY A self-Employed person can make about $115 per hour - to as low as $7.85 a hour. If you work with a company or apprentiship you be making about $15 per hour or about $33 per hour
What is the ampacity of gold silver copper and aluminum?
The ampacity for copper is 1000A per square inch, in some places is 700A psi.
What is 738 miles per hour in miles per second?
There are 60 minutes per hour and 60 seconds per minute, or 60 x 60 = 3600 seconds in one hour. Divide by 3600 738/3600 = 0.205 miles per second
What is the population density of Tortuna?
The population density of Tortuna is 738 people per square kilometer.
What is the population density of Austnes?
The population density of Austnes is 738 people per square kilometer.
What is the maximum number of devices connected per ieee 1394 controller?
63
What is IEEE 1394?
IEEE 1394 is a standard for a type of connection media. Typically known as Firewire.
What is your CGPA if your percent is 86.5?
82.1 if it is as per CBSE calculations.
What is a sentence with calculations?
i can calculate the number of apples per tree
What is the speed between super computer and human brain?
Think of it this way, our brain can do like 1-3 calculations per second, a super computer can do trillions and billions of calculations per second.
How many calculations a normal destop PC can process per second?
A typical desktop PC can perform billions of calculations per second, often measured in FLOPS (floating-point operations per second). For example, modern CPUs can execute around 3 to 5 gigahertz, meaning they can process billions of instructions per second. Additionally, with multiple cores and hyper-threading, the total number of calculations can rise significantly. Overall, a standard desktop can handle anywhere from several billion to over a trillion calculations per second, depending on its specifications.
How far is Nashville TN To Coldspring Texas?
The driving distance from Coldspring, Texas to Nashville, Tennessee is 738 miles per MapQuest. The driving time per MapQuest is 11 hours and 22 minutes.
How fast is 1500 mhz?
1.5 GHz, 1500000000 Calculations per second.
