Technical data and terminology

HOME > Technical data and terminology > Technical data : Lightning protection > Comparison of lightning-proof transformers and power supply protective devices

Comparison of lightning-proof transformers and power supply protective devices

 
 
Discharge type (protective device)   Insulation type (lightning-proof transformer)
 
 
Type Strengths Weaknesses

Protective devices

(discharge type)

● Limits lightning surge voltage to lower than the withstand voltage of the equipment, and protects the equipment from damage.

● Equipment costs are comparatively low and installation is easy.

● Installation space can be kept to a minimum.

● There is a risk of damage if the current exceeds the capacity of the elements.

● Protective devices have a limited life and need to be replaced regularly.

● Lightning surge current flows to the ground, so there is a risk that electromagnetic induction voltage will be generated by the surge current.

● Current flows to the ground, so electropotential difference is sometimes generated between grounds.

Lightning-proof transformers

(insulation type)

● The lightning-proof transformer isolates the voltage between the grounds, so there is almost no voltage applied to the equipment (the surge transfer rate is less than 1/1000, so the protection provided is greater than that of a protective device).

● There is no upper limit on surge withstand capacity.

● Lightning surge does not flow to the ground, so there is no electromagnetic induction voltage risk.

●Lightning surge does not flow to the ground, so there is no electropotential difference risk.

● The device itself gets larger in proportion to the capacity.

● The equipment costs are high.

● If the applied voltage is inordinately higher than the withstand voltage value, there is a danger of withstand voltage damage. (Withstand protection versions are available to counter this.)
 
 
 

Lightning protection

 

Lightning rod (air termination section) angle of protection

The relationship between impulse and DC spark-over voltage

Withstand voltage of communications equipment

Basic concepts of lightning protection countermeasures

Installation locations of protective devices

●Comparison of lightning-proof transformers and power supply protective devices

Equipment withstand voltage damage

Methods of wiring protective devices

 

How lightning enters

The effect of lightning

Lightning protection related standards

Lightning damage and the human body

Arrester follow current

Operating principles of protective devices (when compared to water…)

Methods of protecting telecommunications equipment

Electropotential (voltage)

 
 
 

PAGE TOP