Wiki
Home » Blog » Wiki » What is the surge impedance load?

# What is the surge impedance load?

The surge impedance loading (SIL) of a line is the power load at which the net reactive power is zero. So, if your transmission line wants to "absorb" reactive power, the SIL is the amount of reactive power you would have to produce to balance it out to zero. You can calculate it by dividing the square of the line-to-line voltage by the line's characteristic impedance.

Transmission lines can be considered as, a small inductance in series and a small capacitance to earth, - a very large number of this combinations, in series. Whatever voltage drop occurs due to inductance gets compensated by capacitance. If this compensation is exact, you have surge impedance loading and no voltage drop occurs for an infinite length or, a finite length terminated by impedance of this value (SIL load). (Loss-less line assumed!). Impedance of this line can be proved to be sqrt (L/C). If capacitive compensation is more than required, which may happen on an unloaded EHV line, then you have voltage rise at the other end, the ferranti effect. Although given in many books, it continues to remain an interesting discussion always.

The capacitive reactive power associated with a transmission line increases directly as the square of the voltage and is proportional to line capacitance and length.

Capacitance has two effects:

1 Ferranti effect
2 rise in the voltage resulting from capacitive current of the line flowing through the source impedances at the terminations of the line.

SIL is Surge Impedance Loading and is calculated as (KV x KV) / Zs their units are megawatts.

Where Zs is the surge impedance....be aware...one thing is the surge impedance and other very different is the surge impedance loading.
thank you for your valuable information regarding sil...
---->> by
nice explanation
---->> by
thank you for your basic information which i donot know
---->> by
Very clear explanation on the topic.
---->> by

Calculate (2 + 1) =

You may also like:

r/min: motor rotation speed unit, the number of revolutions per minute, also can be expressed in rpm. For example: 2-pole motor 50Hz 3000 r/min, 4-pole motor 50Hz 1500 r/min Conclusion: The motor rotation ...
My experience with the types of motors in electric vehicle is the following. There are three choices for motors in EVs, permanent magnet PM, integral permanent magnet IPM, and induction motor IM. They each ...
The PPE (Personal Protective Equipment) requirements to work on live electrical equipment is making doing commissioning, startup, and tuning of electrical control systems awkward and cumbersome. We are at a ...
For small circuit breakers we can do the test of Magnetic protection behavior by using "Injection Current Apparatus", and suppose the CB's results were good, do you think it's enough? I'm sure not, because by ...
The biggest differences between the floor programmer and the office programmer is often a piece of paper (knowledge and experience do not replace a piece of paper in the mind of HR person that has no ...
Gozuk Blog: all about electric motor control & drives industries development in energy saving applications.

Featured

Like pumps, fans consume significant electrical energy while serving several applications. In many plants, the VFDs (variable ... A frequency inverter controls AC motor speed. The frequency inverter converts the fixed supply frequency (60 Hz) to a ... Motor starter (also known as soft starter, motor soft starter) is a electronic device integrates soft start, soft stop, ... Soft starter allows the output voltage decreases gradually to achieve soft stop, in order to protect the equipment. Such as the ... Soft Starter reduces electric motor starting current to 2-4 times during motor start up, reduces the impact to power grid during ...

In Discussion