What is the distance between the arrester and the distance from the protected transformer?
Transformers at different voltage levels have different levels of standard insulation, such as 110kV transformers, standard lightning impulse, full wave withstand voltage, 480kV, 220kV transformer, standard lightning impulse, full wave withstand voltage, 950kV.
The protection range of lightning arrester is limited, when the line between the transformer and arrester protection distance, once was struck by lightning, the lightning current forward is very steep, very high frequency, the line impedance is also high, although the lightning arrester action, but the protection of the long distance, because the line the impedance of the transformer protection is checked, or will appear over voltage insulation crisis, remember when the distance is more than 80M not
The residual pressures of 110kV and 220kV metal Zinc Oxide arresters under nominal discharge current are 260kV and 520kV respectively.The maximum distance between arrester and transformer is considered the insulation coordination between arrester residual voltage and transformer at different voltage levels.
According to the overvoltage and insulation coordination for AC electrical installations for lightning protection transformer lightning arrester from the prescribed maximum electrical distance transformer should consider 3 factors, nominal system voltage, line length and line number.
