Fault Analysis of Emergency Diesel Generator

Nov. 15, 2019

Emergency power supply (EPS) is composed of fire protection facilities, emergency lighting, accident lighting and other first-class load power supply equipment. In this article, Starlight Power mainly introduces the fault analysis of emergency diesel generator.

As a backup power source, emergency diesel generator set provides AC power to the load in case of main power failure, ensuring continuous power supply of the load. It is widely used in various industries such as communication, coal mine, etc., and various faults occurred in the operation of the diesel generator set. Most of them are caused by untimely, inoperative or improper operation of the operation manager.

Emergency Diesel Generator Failure

Fault	Fault characteristics and causes	Elimination method
Oil pressure alarm shutdown	Pressure sensor broken	Replace the pressure sensor
	Poor quality of lubricating oil	Replace the lubricating oil
	Oil filter is dirty	Replace the oil filter
	Pressure valve failure	Repair or replace pressure valves
	Oil pump failure	Replace the oil pump
	Insufficient oil	Add oil
High water temperature alarm and stop	Insufficient cooling water	Add cooling water, the cooling water must be distilled water
Engine cannot start	Water temperature sensor is broken	Replace the water temperature sensor
	Tubing has air	Check, exhaust air
	Tank valve is not open	Open the oil tank valve
	Oil tank without oil	Add fuel
	Poor fuel quality	Replace the fuel
	Starter motor failure	Replace the starting motor
	Insufficient battery capacity	Charge the battery
	Battery terminal oxidation, poor contact	Rust removal, fasten battery connection bolt
	High pressure oil pump failure	Repair or replace the oil pump
	Air filter is blocked	Replace or clean air filter
Diesel engine power	Fuel line, fuel filter into air or blocked	Remove air or replace fuel filter cartridge
	Fuel injection pump does not atomize oil	Check for repair or replacement of coupling parts
	The generator body is overheated, the ambient temperature is too high, the temperature of the oil and cooling water is high, and the discharge temperature is also greatly increased.	Check the cooler and radiator to remove scale; check if the pipe diameter is toosmall. If the ambient temperature is too high, the ventilation should be improved to improve the cooling effect.
There is abnormal noise when the diesel engine is running.	The transmission gear is worn and the tooth gap is too large; the front cover emits an abnormal sound, and when the engine suddenly drops, the impact sound can be heard.	Adjust the backlash and replace the gear according to the wear condition
	Inlet and the exhaust valve clearance is too large, and a loud rhythmic noise is heard at the cylinder head.	Recalibrate the valve clearance
	There is no oil between the rocker arm adjusting screw and the spherical seat of the push rod. The "squeak" of dry friction is heard at the cylinder.	Add oil
Exhaust black smoke	Air filter blocked, intake air blocked	Check and clean the air filter
	The fuel supply of each cylinder is uneven.	Adjust the fuel injection pump
	Incorrect valve clearance and poor valve seal	Adjust the valve clearance, check the sealing cone, and eliminate the defects
Exhaust white smoke	The atomization of injector is poor, there is oil drop phenomenon, and the injection pressure is insufficient.	Check the nozzle couplings for grinding or replacement, and re-adjust the injection pressure to the specified range
Exhaust white smoke	Incomplete combustion in individual cylinders when the engine is just started	Increase the speed and load properly, and run more time.

Emergency Diesel Generator Start-up Operation

Release the "emergency stop" button on the control panel.

Turn the power switch knob on the control panel to the “ON” position, the power indicator light is red, and the generator's controller power is on and displays normally.

Press the manual button on the generator controller panel, the indicator on the manual button lights up, and a palm is displayed in the lower right corner of the LCD screen. This is the manual start mode.

Press the start button on the generator controller panel to start the generator, the generator start indicator lights up, and the LCD screen shows that the three-phase voltage rises from 0V to 230V.

Check the generator for abnormal noise or vibration, whether there is oil leakage, water leakage or air leakage, and whether the control panel displays abnormality.

After confirming that the generator power output has stabilized at about 230V, close the generator control cabinet output circuit breaker, and the diesel generator starts normal power supply.

emergency diesel generator

Emergency Power Output Operation

Check the emergency power supply incoming cabinet breaker, the voltage output shows about 230V, and check that the output status of each feeder circuit is normal.

Operation of Emergency Power Distribution Cabinet in Each Substation

Check and confirm that the incoming power supply of the emergency power distribution cabinet of each substation has been cut to the generator power supply state (backup power supply).

If ATS is not switched to the standby power state, the ATS control switch is cut to the manual state, and the special handle is used to manually switch to the standby power supply state (generator power supply).

Check the normal power supply status of each feeder circuit of the emergency power distribution cabinet.

After the diesel generator is working normally, it is necessary to check the running state of the generator and the output current, voltage and other parameters.

Emergency Diesel Generator Shutdown Operation

Confirm that the incoming power supply of the emergency power distribution cabinet of each substation has been cut to the mains power supply (common power supply).

Confirm that the load has completely exited and disconnect the generator emergency power inlet cabinet circuit breaker.

Disconnect the generator control cabinet output main circuit breaker.

Make sure that the generator is cooled for about 3 minutes at idle speed, then press the stop button on the generator controller panel, the stop button indicator lights up, and the generator stops normally.

If there is an emergency to stop the generator, you can not turn off the generator control cabinet output circuit breaker, directly press the red "emergency stop" button on the controller panel, and the generator will stop in an emergency.

After confirming that the generator is stopped, turn the power switch knob on the control panel to the “off” position, the power indicator light is off, and press the “emergency stop” button to complete the shutdown of the diesel generator.

Notes:

When the diesel generator is running at no load, it shall not exceed 5 minutes.

Do not take off the battery during the operation of the diesel generator to avoid the damage of electronic components.

Do not open the lid of the water tank before the diesel generator set is cooled to prevent scalds.