The invention provides a detection circuit suitable for the on-line temperature of a high-
voltage solid-state soft
starter, belonging to the technical field of the starting of a high-
voltage motor, and mainly aiming at solving the problem that the existing temperature protection technology only sets the every-time starting time interval to realize the temperature protection of a
thyristor and can not meet the field demand. The circuit is mainly characterized by comprising a
high voltage-side detection circuit which is formed by the means that a temperature
signal acquisition circuit, a
voltage amplifier circuit, a voltage / frequency switching circuit and an optic
fiber transmitting circuit are sequentially connected with one another, and a
low voltage-side switching circuit which is formed by the means that an optic
fiber receiving circuit and a frequency / voltage switching circuit are sequentially connected with each other; and the optic
fiber transmitting circuit in the
high voltage-side detection circuit is connected with the optic fiber receiving circuit of the
low voltage-side switching circuit by an optic fiber. The detection circuit is higher in
cost performance, a V / F (voltage / frequency) optic
fiber transmission system of the detection circuit has the characteristics of being long in distance, anti-jamming, high in linear precision, good in performance and the like, and the detection circuit is mainly used for the on-line temperature of the
thyristor in high-voltage
starter starting equipment.