Diesel Generator Set Emergency Shutdown vs. Normal Shutdown

In the process of using a diesel generator set, shutdown is an unavoidable procedure. Whether it is a planned normal shutdown or an emergency shutdown in sudden situations, the correct operating steps are of vital importance. This article will give a detailed introduction to the correct methods and precautions for emergency shutdown and normal shutdown of diesel generator sets, helping users safely and effectively stop the operation of the generator set in different situations.

Emergency shutdown is usually a measure that must be taken when a generator set experiences faults or sudden situations. These situations may pose threats to equipment or operator safety, so it is necessary to immediately stop the operation of the generator set. The following are common situations requiring emergency shutdown and the corresponding operating steps.

Electrical system faults: When a short circuit, smoke, or insulation breakdown occurs at the generator output terminal, shutdown must be performed immediately.

Control cabinet abnormalities: If the control cabinet shows abnormally high temperature, burning smell, or arcing phenomenon, this may be a precursor of equipment damage and requires emergency shutdown.

Voltage abnormality: When the output voltage of the generator set exceeds the maximum reading on the meter, it may damage connected equipment, and emergency shutdown must be performed.

Mechanical faults: Sudden drop or no oil pressure, rapid rise in coolant or oil temperature, abnormal knocking sound in the diesel generator set movement, fuel pipeline rupture, component damage, abnormal exhaust smoke and heating, red light of high-temperature fault indicator, unit catching fire, serious fuel/lubricating oil leakage, electric shock to personnel, equipment tipping over, as well as sudden smoke inside the generator, scorched odor, leakage endangering the generator set or operator safety, natural disasters, automatic overspeeding (runaway phenomenon), abnormal voltage/frequency unable to recover through normal adjustment, seizure of moving parts such as cylinder, piston, bearing shell, governor, sudden change of diesel generator sound or speed, etc., all require immediate emergency shutdown measures.

Immediately execute emergency shutdown program: In an emergency, quickly press the emergency shutdown button or pull the emergency shutdown switch. The emergency shutdown button is usually red and located on the control panel, used to stop the engine in emergencies. Do not use this button during normal shutdown.

Cut off fuel supply: After pressing the emergency shutdown button, immediately cut off fuel supply to stop generator operation. This can be done by turning the fuel injection pump switch handle to the oil cut-off position.

Turn off generator power supply: After cutting off fuel supply, turn off the generator power supply to ensure the generator completely stops running.

Check cause of failure: After emergency shutdown, immediately check the cause of the fault. If possible, take appropriate repair or maintenance measures. In any case, promptly contact professional maintenance personnel for a full inspection, identify the fault, and resolve it in time.

Safety first: After emergency shutdown, ensure all operators are in a safe position, avoiding contact with hot components or leaking fluids.

Record fault situation: Record in detail the situation when the fault occurred, including fault phenomenon, shutdown time, etc., so that maintenance personnel can quickly diagnose the problem.

Professional repair: After emergency shutdown, the generator set may have serious faults, so promptly contact professional maintenance personnel for inspection and repair. Do not attempt to repair on your own to avoid causing greater damage.

Normal shutdown refers to stopping the operation of a diesel generator set according to a planned procedure and steps. Normal shutdown is usually performed after the generator set completes its work, with the purpose of ensuring the equipment remains in good condition after shutdown and avoiding damage caused by sudden shutdown. The following are the key steps and precautions for normal shutdown.

Check generator running status: Before shutdown, ensure the generator is running normally and check whether various indicators are normal. This includes checking oil pressure, coolant temperature, oil temperature, voltage, frequency, etc.

Gradually reduce load: Before shutdown, gradually reduce the load so the generator gradually returns to no-load condition. This can be achieved by gradually reducing connected equipment or lowering the power of equipment. Gradually reducing load avoids the generator bearing excessive load during shutdown, reducing equipment wear.

Wait for generator cooling: After load reduction, wait for a period to ensure the generator has cooled. It is generally recommended to let the generator run at no load for 3–5 minutes before proceeding to the next step. The cooling process can prevent the generator from overheating after shutdown, thereby extending service life.

Shut off fuel supply: After the generator has cooled, shut off the fuel supply so the generator gradually stops running. This can be achieved by turning the fuel injection pump switch handle to the oil cut-off position.

Turn off generator power supply: After fuel supply is shut off, turn off the generator power supply to completely stop operation. This can be done by setting the power output switch to the “OFF” position.

Check coolant temperature: Before shutdown, ensure outlet coolant temperature drops below 75°C. If the temperature is too high, wait until it drops to a safe range. It is prohibited to immediately shut down when engine temperature exceeds the limit, as this may cause the engine temperature to rise further.

Pull the shutdown handle: When coolant temperature drops to a safe range, pull the shutdown handle on the governor to stop the diesel generator.

Eliminate faults: After shutdown, promptly eliminate any faults discovered during operation. If any abnormal situations are found during operation, inspect and repair immediately after shutdown.

Maintenance: After each shutdown, perform maintenance as required. This includes checking levels of oil, coolant, and fuel, cleaning equipment surface, checking electrical connections, etc. Regular maintenance can extend generator set service life and ensure normal operation next time.

Switch off main circuit breaker: After each shutdown, switch off the main circuit breaker, disconnect battery negative terminal, and disconnect load cables. This prevents accidental startup during shutdown, ensuring safety of equipment and operators.

Special treatment for long-term storage: For diesel generators requiring long-term parking, during the final shutdown, drain used oil, replace with preservation oil, run for about 2 minutes for sealing, and drain coolant (including antifreeze). Remove the battery and send it to the battery room for maintenance. This prevents equipment damage during long-term storage.

Although both emergency shutdown and normal shutdown are operations to stop the generator set, their triggering conditions, operating steps, and precautions are very different. Emergency shutdown must be taken immediately in sudden situations or equipment failures, aiming to prevent equipment damage or protect operator safety. Normal shutdown, however, is performed within plan, following prescribed procedures and steps, aiming to keep the equipment in good condition after shutdown and avoid damage caused by sudden shutdown.

Emergency shutdown: Usually a measure taken when faults or sudden situations occur in the generator set. These situations may threaten equipment or operator safety, such as electrical system faults, control cabinet abnormalities, voltage abnormalities, mechanical faults, etc.

Normal shutdown: Usually performed after the generator set completes work, aiming to ensure equipment is in good condition after shutdown and avoid damage caused by sudden shutdown.

Emergency shutdown: Requires immediate execution of emergency shutdown procedures, including pressing the emergency shutdown button, cutting off fuel supply, turning off generator power, etc. After emergency shutdown, immediately check fault causes and contact professional maintenance personnel for inspection and repair.

Normal shutdown: Requires following prescribed procedures and steps, including checking generator running status, gradually reducing load, waiting for generator cooling, shutting off fuel supply, turning off generator power, etc. After normal shutdown, promptly eliminate faults found during operation and perform maintenance as required.

Emergency shutdown: After emergency shutdown, ensure all operators are in a safe position, avoiding contact with hot components or leaking fluids. Record fault conditions in detail for maintenance diagnosis. Do not attempt to repair on your own to avoid further damage.

Normal shutdown: Before shutdown, ensure generator is running normally and check whether indicators are normal. Gradually reduce load, wait for cooling. After shutdown, promptly eliminate faults found during operation, perform maintenance as required, switch off main circuit breaker, disconnect battery negative terminal, and disconnect load cables. For long-term storage diesel generators, perform special treatment, such as replacing preservation oil, draining coolant, etc.

Whether emergency shutdown or normal shutdown, correct operating steps and precautions are of vital importance. Emergency shutdown is a measure that must be taken immediately in sudden situations or equipment faults, aiming to prevent equipment damage or protect operator safety. Normal shutdown is performed within plan, following prescribed procedures and steps, aiming to keep the equipment in good condition after shutdown and avoid damage caused by sudden shutdown. In any situation, operator safety must be ensured, and professional maintenance personnel contacted promptly for inspection and repair. Through correct shutdown operations and regular maintenance, the service life of diesel generator sets can be extended, ensuring the equipment operates normally during the next use. It is hoped this article can help you better understand the correct operation methods and precautions for emergency shutdown and normal shutdown of diesel generator sets. When using diesel generator sets, strictly follow operating procedures to ensure the safety of equipment and operators.