Single-phase protection circuit for high-voltage motors

When the single-phase grounding current of the high-voltage motor
reaches 5A, single- phase grounding protection should be installed, and the wiring is as shown in the figure.
    The operating current Inp (E) of the single-phase grounding protection should be set according to the capacitive current k
of
the motor , that is, The tuning calculation
formula is
    Iop(E)=k. 1 XJm/Ki
In the formula, ki - the reliability coefficient of the protection device, takes
    the conversion ratio of 4-5, K, -TAN.
    The operating current of single-phase grounding protection can also
be set approximately according to the sensitivity coefficient Sp of the protection (usually 1.5), that is,
    k (E) = (L- h,)/KiSp
where L - and the high-voltage current The motor stator winding is electrically connected to
    the single-phase ground capacitance current of the entire power grid;