1. The excitation circuit is grounded. There are two types of grounding of the excitation circuit: one-point grounding and two-point grounding. Generally speaking, when the excitation circuit is grounded at one point, there is no serious harm to the diesel generator. However, if the maintenance is not timely, it may lead to grounding at two points, destroy the balance of the rotor magnetic flux, cause strong vibration, and eventually burn out the rotor winding.
2. Overvoltage. When the load is suddenly dumped during operation, if the maintenance is not timely, overvoltage may occur due to the large inertia of the speed control system, resulting in breakdown of the winding insulation.
3. Stator overcurrent. Stator overcurrent is generally caused by external short circuit or system oscillation. If the maintenance is not timely, the temperature of the stator will increase and the aging of the insulation part of the winding will be accelerated; if it is serious, other faults will occur.
4, overload. Overload refers to operation beyond the rated capacity. If the maintenance is not timely, the overload operation for a short time will cause the temperature of the stator winding to rise, accelerate the aging of the insulation part, and shorten the service life. If it is overloaded for a long time, it may cause the stator winding to burn, and eventually cause the failure of power generation.
5. If the maintenance is not timely, there will be a short circuit between the turns of the stator winding. When the stator winding is short-circuited between turns, a loop current will be generated under the action of the short-circuit voltage. If it is not repaired in time, the inter-turn short circuit may develop into a single-phase grounding short circuit and an inter-phase short circuit. The multi-phase-to-phase short-circuit of the stator winding will cause the greatest damage to the power generation equipment if the maintenance is not timely, and the short-circuit current will cause burnout. Single-phase grounding of stator winding When a single-phase grounding fault occurs in the stator winding, the current flows through the stator core, which will cause the core to burn, or even partially melt the core.
6. If the maintenance is not timely, the excitation current drops sharply. When the excitation current drops sharply or disappears, a large amount of reactive power will be absorbed from the system, and the synchronous operation will be converted into asynchronous operation, which will cause the system voltage to drop, and will lead to system collapse in severe cases.
Post time: May-19-2022