Reasons for damage to rectifier diodes

Reasons for damage to rectifier diodes

(1) The lightning protection and overvoltage protection measures are inadequate. The rectifier device is not equipped with lightning protection and overvoltage protection devices. Even if lightning protection and overvoltage protection devices are installed, their operation is unreliable and the rectifier diode may be damaged due to lightning strikes or overvoltage.

(2) The operating conditions are harsh. Indirect transmission generator sets, due to incorrect calculation of the ratio of rotational speeds or the ratio of the diameters of the two pulleys not meeting the requirements of the ratio of rotational speeds, cause the generator to operate at high speeds for a long time, and the rectifier diodes also work at high voltages for a long time, which accelerates the aging of the rectifier diodes and causes premature breakdown and damage.

(3) Poor operational management. The on duty operators are irresponsible in their work, not familiar with changes in external loads (especially between midnight and 6am the next day), or when there is a load shedding fault, the operators do not take timely action, resulting in overvoltage and damage to the rectifier diode.

(4) The equipment installation or manufacturing quality is not up to standard. Due to the long-term operation of the generator set under significant vibration, the rectifier diodes are also subjected to external interference caused by this vibration; At the same time, due to the high and low speed of the generator set, the working voltage borne by the rectifier diode also fluctuates rapidly, which greatly accelerates the aging and damage of the rectifier diode.

(5) The specification and model of the rectifier diode do not match. When replacing a new rectifier diode, mistakenly replacing a diode with working parameters that do not meet the requirements or wiring errors can cause the rectifier diode to break down and be damaged.

(6) The safety margin of the rectifier diode is relatively small. The overvoltage and overcurrent safety margin of the rectifier diode is too small, which makes the rectifier diode unable to withstand the peak values of overvoltage or overcurrent transient processes that occur in the generator excitation circuit and cause damage.