What is the rating of lightning arrester?
Rated Nominal Discharge Current There are mainly four standard current ratings available and these are 1.5 KA, 2.5 KA, 5 KA, and 10 KA. In the system voltage above 66KV, normally lightning arresters have 10 KA rated nominal discharge current.
How do you choose a surge arrester rating?
The two most important factors used to select an arrester rating are the system voltage and the neutral grounding configuration of the source transformer. These tables assume that the maximum duration and amplitude of the worst-case overvoltage during a line-to-ground fault are unknown.
How many joules do I need for a refrigerator surge protector?
2000 joules
A surge protector with 1000 to 2000 joules will provide sufficient protection for refrigerators, washing machines & dryers, office equipment, and power tools. Consider the highest joule rating (2000+) for expensive gaming consoles, home theater systems, and any computer that stores important data.
How many joules of protection do I need?
Units with surge protector ratings of 1000 to 2000 joules will provide sufficient protection for power tools and office equipment such as printers, copiers and routers. Consider the highest joule ratings—2000 and above—for home theater components, gaming consoles and any computer that stores important data…
How do you choose a lightning arrestor?
How to select a lightning arrestor
- It must have satisfactory service life when connected to the power system.
- Minimum rated arrester must be preferred because it provides the greatest margin of protection.
How do you calculate the range of a lightning arrester?
Down Conductors As per Base Area of Structure (s) =1+(Ab-100)/300
- Down Conductors As per Base Area of Structure (s) =1+(Ab-100)/300.
- Down Conductors As per Base Area of Structure (s) =1+(1680-100)/300.
- Down Conductors As per Base Area of Structure (s) =6 No’s.
- Down Conductors As per Perimeter of Structure (t)= P/30.
How do I protect my fridge from a power surge?
How To Protect Your Appliances During A Power Outage
- Use surge protecting power strips in your home.
- Install a whole-house surge protector in your electrical panel.
- Contact your electricity provider about meter-mounted surge protection.
- Install GFCI outlets throughout your home.
Is 1080 joules enough for a TV?
Recommendations. Electronic accessories manufacturer Belkin recommends its 1,411 joule model for most TV sets, or its 2,444 joule unit for projection televisions. ReviewSurgeProtector.com similarly advocates a minimum level of 1,500 joules for TVs.
How do you calculate the radius of a lightning arrester?
To calculate the different radii of protection of a ESE lightning rod, we must know the variables involved in the formulation: INGESCO PDC 3.1 model has ΔT=15 µs and thus Δ=15 m. Apply level II protection, the notional sphere radius corresponds to r = 30m. Consider the height h = 20m.
What are the ratings of a lightning arrester?
The ratings of a lightning arrester depend on three main factors such as rated voltage, rated frequency, and rated nominal discharge current. All lightning arresters should withstand the maximum continuous operating voltage (MCOV).
Which is the recommended spark overvoltage for lightning arresters?
As per IS 3070, the recommended spark overvoltage is 1.5 times the rated voltage. There are also other ratings like maximum impulse spark over-voltage, residual or discharge voltage, maximum discharge current, etc. Here we are selecting an appropriate rating of lightning arresters for the substation.
Why is arrester rating less than line to line voltage?
In many cases, the arrester rating is less than the line-to-line voltage because arresters are applied line to ground. The line-to-ground voltage is line-line voltage divided by 1.73, for those wishing to calculate it.
What is the discharge voltage of a mcov arrester?
The lower the discharge voltage, the better. Continuing with the above example, an 88kV MCOV arrester when subjected to a 10kA lightning impulse generates 254kV discharge voltage across arrester terminals. This is acceptable considering this rating is well below the adjusted BIL rating of a 138kV piece of equipment (520kV).