Greetings! In the previous article on diesel engines, we discussed the protection of auxiliary diesel generators, which are most often tested on a ship during inspections in ports. In this article, we will consider the protections of an emergency diesel generator, as well as the procedure for testing a blackout of a ship's power plant.
-min.JPG "Blackout Test. Protection of an emergency diesel generator")
At first I wanted to write that the protection of the emergency diesel generator (EDG) in ports is checked very rarely, but recently the Belgian PSC suddenly decided to check the protection of our emergency diesel. Therefore, in order to always be prepared for any checks, it is worth being aware of all the protections that this engine has.
In this article, we will consider the EDG protection using the example of a MITSUI / DEUTZ TCD914L06M 129 kW diesel engine and a CUMMINS / STAMFORD UC.M274F1 generator with a JRCS alarm system. But the article will contain the experience of operating more than a dozen different vessels and cases.
In fact, on all vessels, the protection of emergency diesel engines is approximately the same, but there may be minor differences.
According to the manual, this diesel engine has 6 alarms. And what is most interesting is that none of them stop the engine. That is, there is an alarm and no shutdown. This is explained by the fact that the EDG on the ship is a critically important emergency mechanism that participates in the fight for the survivability of the main power plant of the ship, and even if some problems occur with it, it must work as long as possible to help the crew restore the operation of auxiliary diesel generators in the event of a blackout.
The emergency diesel generator on board a vessel plays a key role in ensuring safety and uninterrupted operation of systems in the event of failure of the main power plant. Its main functions include:
1. Providing emergency power for safety systems:
- Emergency lighting on board the vessel (e.g. bridge, engine room, evacuation areas).
- Alarm systems such as fire and emergency systems.
- Life-saving equipment (e.g. lifeboat and liferaft launching systems).
2. Power supply for critical systems:
- Communication systems (radio and satellite communications).
- Navigation instruments (radar, echo sounder, GPS).
- Fire-fighting and ballast pumps.
3. Backup power supply for vital installations:
- Cooling and ventilation systems.
- Pumps for fuel, oil and water, if necessary to maintain minimum operation of the vessel.
4. Ensuring the vessel's maneuverability (if necessary):
- If the diesel generator has sufficient power, it can power the steering systems or some elements of the propulsion and steering system for safe maneuvering.
The emergency generator must be independent of the vessel's main power supply, so it is installed in a separate room, remote from the engine room, to minimize the risk of damage in the event of an accident. It is also equipped with an automatic start system, which is triggered when the vessel's main power supply fails.
To understand how the emergency diesel generator protections work, you need to know the procedures for starting it in different ways. Let's consider each of them in more detail.
The procedure for starting the emergency diesel generator in manual mode (by batteries)
Usually, on all ships, the manual start of the emergency diesel is approximately the same. It is necessary to check that the battery group (first or second) is selected, switch the emergency diesel mode to manual mode and press the Start button or pull the ENG CONTROL handle and move it to the "Start" position (in our case). And the engine will start. In this case, it is worth paying attention to the engine speed, idle voltage and generator operating frequency.
Attention! In this article, I consider starting an emergency diesel generator only by batteries, although there are other methods.
Let's look at the Flow Chart (process diagram) of starting the EDG in manual mode and taking it to the buses.
In the photo above you can see the so-called Flow Chart of starting the EDG in manual mode. Usually such block diagrams can be found in the instructions for the ESB (Emergency Switch Board). These diagrams explain the automatic start and stop of the engine.
Flow Chart (manual start of the EDG)
- The engine is stopped and ready to start (the READY TO START light is on);
- The engine is switched to manual mode (MANU CONT AVAIL);
- Pull the ENG CONTROL handle and move it to the "Start" position;
- The engine starts, within 28 seconds it picks up speed (SPEED PICK UP reads the speed and signals normal engine operation);
- VOLT ESTABLISH - the idle voltage is set. The ACB circuit breaker is checked - closed;
- The BUS TIE CHANGE SW switch is moved to the "E/G SIDE" position; The generator "sits" on the busbars and supplies power to emergency consumers.
Flow Chart (manual stop of the emergency diesel generator)
Here the same thing happens only in the opposite direction. It is necessary to move the BUS TIE CHANGE SW switch to the "MSB SIDE" position, the generator will be disconnected from the buses. Then you need to manually stop the engine using the ENG CONTROL handle, move it to the "Stop" position. The engine will stop. After that, you need to return the operating mode to "Auto".
Below I suggest watching a video of starting different emergency diesel generators, there is not much difference in the procedure.
- Video of starting the DEUTZ / CUMMINS / STAMFORD EDG (in manual mode)
- Video of starting the DEUTZ / CUMMINS / STAMFORD EDG (in manual mode)
- Video of starting the CUMMINS / STAMFORD EDG (in manual mode)
- Video of starting the CUMMINS / STAMFORD EDG (in manual mode)
- Video of starting the STX 6CTA8.3DMGE EDG (in manual mode)
Procedure for starting the emergency diesel generator in automatic mode
Automatic starting of the diesel generator will be discussed mainly below, in the Blackout Test section.
According to the requirements of the International Convention SOLAS (Safety of Life at Sea) and the standards of classification societies, the emergency diesel generator (EDG) on a vessel must have at least two independent starting methods. This ensures its reliability even if one of the methods fails.
The main methods of starting the EDG:
1. Electric starting:
- It is carried out using batteries, which are part of the emergency system.
- This is the most common and fastest method.
2. Pneumatic starting:
- Compressed air stored in high-pressure cylinders is used.
- A reliable method that does not depend on the electrical system.
3. Manual (mechanical) starting:
- It is carried out manually, for example, using a manual starter or flywheel.
- Usually used as a backup method if other methods are not available.
4. Hydraulic starting:
- Uses the energy of the hydraulic system to rotate the starter.
- It is used less often, but is also considered reliable.
Requirements for the starting system:
- All starting methods must be independent of each other.
- Batteries for electric starting must be in the emergency zone and protected from overloads.
- Compressed air or other means must be in sufficient volume for several starting attempts.
Such a variety of starting methods guarantees that the emergency generator will be ready for operation even in the most difficult conditions.
Let's consider in detail all the alarms of the emergency diesel generator.
Thermo switch (CYL. HEAD HIGH TEMP) - high temperature of the cooling water. This protection is triggered when the engine cooling water temperature is above 150 ° C. Usually, to check it, it is enough to lower the red arrow of the temperature sensor below the arrow of the current temperature.
The photo above is taken incorrectly, you need to move the red arrow below the current temperature arrow, and not vice versa. This is usually enough. If desired, you can use a temperature calibrator.
Start failure - unsuccessful start of the diesel engine (3 times). If the diesel generator failed to start after three attempts, then the corresponding alarm "START FAIL" should appear. You can simulate such an alarm, for example, by disconnecting the starter batteries and trying to start the diesel engine.
By the way, when disconnecting the starter batteries, the corresponding alarm should appear on the alarm monitoring system (AMS) in the ECR, but this signaling is not always provided. Therefore, it is necessary to periodically check that the battery selection switch is set to some starting group.
L.O. pressure switch (L.O. LOW PRESS) - low engine oil pressure (0.14 MPa). This alarm can be made on the corresponding pressure switch, for this purpose the oil is shut off to it and the pressure is released below 1.4 kg. If desired, a pressure calibrator (press pliers) can be used.
Overspeed - exceeding the permissible engine speed (2040 rpm). Engine overspeed is triggered when the speed exceeds 2040 rpm. To check this alarm, you need to rev up the speed on the regulator using a special washer.
Deficiency. On one vessel, the American PSC made a remark. During the operation of the emergency diesel generator, it was discovered that the tachometer, which shows the engine speed, was not working. It is very important to check the serviceability of all the EDG instruments at least once a week.
Switch for fan belt broken - a switch for breaking the fan belt. A special pressure sensor is installed and if the belt starts rubbing on it, then a corresponding signal is sent.
You can check by pressing the pressure pin while the engine is running.
F.O. high press. pipe leak - high level in the fuel leak tank. Usually simulated by raising the float or using diesel fuel, which is poured into the tank with a float (the alarm is triggered by a time delay of 5 - 10 seconds).
Thus, we have analyzed the main protections of emergency diesel generators and standard methods for checking them.
Analog sensors. The procedure for checking the EDG sensors, which was described above, is suitable mainly only for discrete sensors. If the system uses analog sensors (thermocouples or pressure transmitters), as is implemented for the CUMMINS - STAMFORD engine on the ComAp InteliDrive DCU control system, then you will have to do the simulation only with the help of calibrators or through the control panel menu.
A video on how to check analog sensors in the ComAp InteliDrive DCU system will be available later.
Next, I suggest considering non-standard cases of checking the EDG, which are rare, but also take place.
Checking starter batteries
Imagine a situation where an inspector requested a check of starter batteries. How? Isn't it enough to start the diesel from batteries and demonstrate a successful start? No, it turns out that you can complicate the task.
It is necessary to disconnect the charger and start the diesel on one group of batteries at least three times. In this case, the diesel should start without problems. This method of checking will reveal non-working batteries (or rather, not working enough).
Deficiency. On one vessel, the African PSC made a remark (deficiency). The emergency diesel generator failed to start for the third time from one battery group with the charger switched off.
Therefore, it is important to check the starter batteries at least once a week. And it is advisable to replace the batteries on a scheduled basis every 4-5 years, depending on their condition.
Deficiency. On one vessel, the Belgian PSC made a remark (deficiency). The emergency diesel generator failed to start from a battery group, but started from a manual (spring) starter. As a result of searching for the cause, a rotten terminal on one of the batteries was discovered. It is important to grease the battery terminals with Vaseline at least once per contract so that they do not oxidize.
Quick-closing valve (QCV) and diesel shutdown
Each emergency diesel generator has its own diesel tank, the volume of which must be sufficient for the engine to operate for at least 18 hours, according to SOLAS.
By the way, in this case, a float with an alarm in the ECR (AMS) is not provided. Therefore, it is important to monitor the fuel level in the tank at least once a week.
Accordingly, this fuel tank must be provided with a quick-shut-off valve, which in the event of a fire in the EDG room must quickly cut off the fuel supply to the diesel.
-min.JPG "Activation of the QCV")
Deficiency. The photo above shows the wire rope for manual activation of the valve. At least once a week, the condition of the wire rope and the operation of the valve should be checked. On one vessel, the Indonesian PSC made a remark - the cable for activating the QCV in the EDП broke during the inspection.
-min.JPG "Fuel tank quick-closing valve EDG")
A quick-closing valve (QCV) is a device designed to quickly shut off the flow of a working medium (liquid, gas or steam) in a pipeline. Such valves are often used in emergency and safety systems where instantaneous flow shut-off is required to prevent leaks, fires or other emergency situations.
Main characteristics of the QCV:
1. Quick response: the valve closes within a fraction of a second.
2. Drive: can be manual, electric, pneumatic or hydraulic. Sometimes a spring mechanism is used for automatic operation.
3. Purpose:
- Protection of equipment and personnel from accidents.
- Limitation of the spread of hazardous substances (e.g. fuel, toxic gases).
- Control of flows in technological process systems.
Examples of application:
- On marine vessels: to quickly shut off the fuel supply in case of fire.
- At chemical plants: to prevent leaks of hazardous substances.
- At power facilities: to control steam or coolant flows.
The quick-close valve must be reliable, hermetic and resistant to corrosion, as it often operates in aggressive environments.
Deficiency. On one vessel, the Chinese PSC made a remark - when the quick-close valve was activated, the emergency diesel generator did not stop. Thus, the quick-close valve did not fulfill its task and did not cut off the fuel supply to the engine.
In fact, the quick-close valve issues do not concern the electrician and therefore I did not consider these checks in the article: "Diesel generator protection. Quick check for the inspector". Here I simply described cases of checking the quick-close valve for general development. Perhaps you will pass on this experience to your fellow engineers in order to pay attention to this during periodic checks of the emergency diesel generator.
Also, the emergency generator rooms should have a button for emergency stop of ventilation. When this button is pressed, the corresponding circuit breakers are tripped. I have never seen inspectors check this button. According to PMS, the check is done once every three months.
Emergency buttons on the vessel. By the way, this button refers to the fire systems on the vessel. We considered groups of such buttons for the engine room, superstructure and deck in the article: "Checking the fire systems on the vessel. What should an ETO know?".
Blackout Test
Here we come to the most interesting question of this article, namely the blackout test on the vessel. The emergency diesel generator here plays a key role in the fight for the survivability of the vessel in the event of a power outage of the main power plant.
In the event of a blackout, the emergency diesel generator (EDG) must start within 45 seconds maximum, according to international standards such as the International Maritime Organization (IMO) and the SOLAS (Safety of Life at Sea) Convention.
However, in real practice and according to the requirements of classification societies:
- The time until the engine starts is usually no more than 30 seconds.
- The time until power is supplied to the emergency circuits is often achieved within 15-30 seconds after a blackout.
Such a fast response time is extremely important to prevent critical situations on board the vessel, such as loss of control or failure of safety systems. To ensure compliance with these standards, the EDG is equipped with an automatic start system, which is activated immediately after power loss is detected.
A blackout test on a vessel can be implemented in different ways, but the main ones are to press a special button EG SEQUENCE TEST (may be called differently) or to de-energize emergency consumers on the emergency switch board (ESB) or on the main switch board (MSB) using a circuit breaker.
What happens if you press this button?
When this button is activated, all emergency consumers of the vessel that are powered by the ESB are de-energized (blackout), then the emergency diesel is automatically started, connected to the buses and powers all emergency consumers. This entire operation should take no more than 45 seconds.
The same thing happens (only in the opposite direction) if you return the button to normal mode. The only difference here is that the emergency diesel may not stop on its own and must be stopped manually. This depends on the automatic control system of the diesel generator. In more advanced systems, the engine should automatically stop 5 minutes after removing the load from it.
As for the inspectors, it is enough for them to demonstrate the test using this button (switch). With rare exceptions, they can ask to cut off emergency consumers from the MSB (Main Switch Board) using circuit breaker.
Video of a blackout test on a vessel using an automatic switch on the ESB
Usually, if the emergency switchboard does not have an automatic breaker, then you can take the emergency generator to the busbars in manual mode using the EG SEQUENCE TEST button or the Bus Tie switch.
Let's look at the processes of automatic start-up of an emergency diesel generator and taking it to the busbars in the event of a main switchboard (MSB) power failure.
Flow Chart (automatic start of the emergency generator)
- Blackout occurs, no power to the emergency switchboard (2 sec);
- A signal is sent to start the emergency generator, the engine starts;
- The engine picks up speed within 28 seconds (SPEED PICK UP reads the speed and signals that the engine is operating normally);
- VOLT ESTABLISH 95% 5 sec - the required 95% of the idle voltage is set (5 sec);
- 35 seconds have passed since the power outage, but the auxiliary standby diesel has not started and has not powered the emergency generator switchboard, which means that the algorithm continues. Otherwise, the emergency generator operates at idle and does not power the buses;
- The emergency generator sits on the buses and powers the emergency consumers.
Flow Chart (automatic stop of the emergency generator)
- Emergency generator on the busbars;
- The emergency generator is in automatic mode and the blackout test switch is in the "NORMAL" position;
- The power supply to the main switchboard is restored;
- The emergency generator is automatically removed from the busbars, emergency consumers are de-energized and powered from the main switchboard.
Flow Chart (EDG blackout test)
The process of the EDG blackout test is not much different from the automatic operation, the only exception here is that the operator manually switches EG AUTO START TEST SW to the "TEST" position and then the automatic start algorithm is executed.
Blackout Test of the Emergency Generator on a Ship (Procedure)
A blackout test is performed to check the operability of the emergency power system, including the emergency generator, in the event of a total failure of the main power supply (blackout). This test is necessary to comply with SOLAS (International Convention for the Safety of Life at Sea) requirements and to ensure the safety of the ship. The procedure is described below.
Purpose of the test
- To ensure that the emergency generator automatically starts and supplies power to essential systems when the main power supply is disconnected.
- To check the operability of the emergency switchboard and the equipment connected to it.
Preparation
1. Risk assessment:
- Conduct a risk assessment to minimize possible hazards during the test.
- Notify the crew of the planned test.
2. System status check:
- Make sure that the main power system is stable before starting the test.
- Check the fuel system, lubrication and cooling of the emergency generator.
3. Isolation of non-essential loads:
- Disconnect or isolate non-essential loads to avoid system overload.
4. Preparation for emergencies:
- Have personnel and tools available to troubleshoot potential problems during the test.
Test Procedure
1. Blackout Initiation:
- Turn off the main generator or open the main circuit breaker to simulate a power outage.
2. Automatic Start of the Emergency Generator:
- Make sure that the emergency generator starts automatically within 45 seconds (SOLAS compliant).
- Check that the emergency switchboard is receiving power.
3. Load Transfer:
- Make sure that power is automatically transferred to essential systems (navigation equipment, lighting, steering, etc.).
- Check that critical systems operate without interruption.
4. Performance Testing:
- Observe the generator under load for a specified time.
- Check parameters such as voltage, frequency and load distribution (if applicable).
5. Main Power Restoration:
- Restore power from the main system and ensure that the load is smoothly transferred back to the main generator.
- Check that the emergency generator automatically shuts down and goes into standby mode.
Post-Test Actions
1. Recording Data:
- Document the test results including generator start-up time, load transfer time and any abnormalities found.
2. System Inspection:
- Check the emergency generator and switchboard for signs of overload or damage after the test.
3. Discussion of Results:
- Discuss the results with the crew, identify and correct any problems.
4. Reporting:
- Prepare a detailed report for regulators and maintenance records.
Key Points
- Ensure compliance with SOLAS requirements, IMO recommendations and the ship’s Safety Management System (SMS).
- Conduct regular maintenance of the emergency generator to ensure its reliability.
- Perform testing within the timeframes specified in the vessel's maintenance plan or as required by the flag state.
Video of a blackout test on a vessel using simulation
What does the inspector need to see?
The main focus of the inspectors here is that the automatic emergency generator start system works without any issues. That is, within 45 seconds the engine starts and the emergency generator is put on the busbars. In this case, emergency consumers that operate from the emergency generator (under load) can be additionally checked selectively.
For example, in my practice there were cases when the emergency generator was started, put on the busbars and the emergency fire pump was started. Or there was a case when the emergency steering gear was started and an emergency rudder shift was made.
Important! Before each blackout test, it is necessary to turn off the navigation equipment, especially the gyrocompass, radars and other important bridge equipment.
All these checks take place, so it is worth preparing for them in advance. I recommend doing blackout tests only when the vessel is in port or at anchor. A blackout test on a vessel is done once every 3 months according to PMS.
That's all! If you have any questions or have something to add, please write in the comments to the article. I would be very grateful!
Manuals! By the way, if you are interested in manuals for diesel generators and systems that were described in this article, I recommend our closed telegram channel Marine Engineering Manuals.
I hope the article was useful for you. Thank you for your attention!
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