Diesel Generator Short Circuit Faults and Solutions

The control section of this diesel generator set adopts phase compound excitation automatic voltage regulation. When troubleshooting such faults, it is important to understand that sudden short circuits during operation can cause delays and significant damage to the generator. Dingbo Power Generator Factory explains the specific hazards and solutions as follows:

Hazards of Sudden Short Circuits

1.Mechanical Damage: The generator winding ends are subjected to high power, leading to deformation or damage of coil ends.

2.Insulation Failure: Voltage surges in stator and rotor windings adversely affect insulation. Strong impulse currents in stator windings, combined with overvoltage, can weak breakdown insulation points.

3.Severe Vibration: The generator may vibrate violently, exerting destructive mechanical stress on structural components.

4.Short Circuit Risks: Stator winding differential protection cannot detect inter-turn short circuits. If left unaddressed, such faults can escalate into major failures, causing heavy losses. Large units should therefore be equipped with stator inter-turn short circuit protection and stator winding fault line protection.

5.Negative Sequence Current Impact: Inter-turn short circuits cause unbalanced three-phase voltages, generating negative sequence currents in the stator. This leads to rotor surface overheating, with negative sequence current not exceeding 8% of the rated current.

Troubleshooting Steps for Short Circuit Faults

1.Check Fuses and Components: Inspect fuses for burnout and control box components for signs of burning. A damaged current-limiting diode was identified in this case.

2.Test Rectifier Diodes: Use a multimeter to test the six rectifier diodes; no abnormalities were found.

3.Address Low Residual Magnetism: After replacing the current-limiting diode and fuse, the generator failed to generate electricity at rated speed. This indicated excessively low residual magnetism voltage in the exciter (likely caused by sudden short circuits in electrical equipment, which can dissipate residual magnetism).

4.Re-excite the Exciter: Re-excite the exciter using a battery. Upon restarting the diesel engine to rated speed, the generator resumed normal power generation, meeting specified requirements.

Guangxi Dingbo Power Equipment Manufacturing Co.,Ltd was founded in 1974 and is one of the earliest manufacturers of generators and diesel generator sets in China. The company has a registered capital of 218.88 million yuan. The company covers an area of 86,000 square meters and a building area of 55,000 square meters. There are more than 660 employees, including 456 professional technicians and 106 senior technicians. It has 46 sales and service outlets nationwide. The main products are diesel engines, generator sets, and diesel generators, providing users with a one-stop service of design, supply, debugging and maintenance at any time. Dingbo has always insisted on using first-class talents, building first-class enterprises, manufacturing first-class products, creating first-class services, and making every effort to build a first-class domestic enterprise. If any question please feel free to visit our website https://www.dieselgeneratortech.com/ or send email to [email protected].