Title: Diesel Generator Control, Protection and Maintenance
Introduction:
The webinar on "Diesel Generator Control, Protection and Maintenance" held on March
12, 2024, provided a comprehensive overview of the critical aspects involved in optimizing
the performance and longevity of diesel generators. Hosted by experts in the field, the
webinar aimed to equip participants with essential knowledge and practical insights into
ensuring the efficient operation and effective management of diesel generator systems.
Keynote speaker:
The webinar featured a distinguished speaker, offering unique insights and expertise in
the field of electrical engineering
Engr. Eduardo Arjona Bangate JR. Is a seasoned electrical engineer and entrepreneur
with over 20 years of diverse experience in the field of electrical engineering in various
Industries that focus on power generation and large industry electrical system
maintenance, currently connected with one of the largest aluminum manufacturing
companies in the world, the Emirates Global Aluminum. He is a professional electrical
engineer and a member of IIEE UAE or United Arab Emirates, a former executive
secretary of the said chapter. He is a former department head of Kohler Power System
or SDMO industry services and maintenance based in Qatar. A France range specialist
on the Brand's latest generator controllers. During his term of service, He led and
performed hundreds of diesel power generator installation commissioning and
maintenance work with notable projects inside, Pearl Qatar, the West Bay in the city of
Doha, and a considerable percentage of luxury Yacht Marine generators including the
EMIR Yacht. An alumnus of Bicol University College of Engineering, he Graduate in the
year 2000 and is currently taking up his Master of Arts in Business and Management at
Bath Spa University United Kingdom, and a Master of Business Administration major in
marketing and brand management po Paris alternative France he is a founder of B&P
Link LLC in the United Arab Emirates a company that provides Engineering Services and
related technical consultancies as well as retail and trade and are currently connected
with the supplier of diesel generators and high voltage Transformer based in Lebanon
and UK a member of Philippine Business Council of Dubai and Northern Emirates and an
advocate of entrepreneurial engineering.
The main parts of the diesel generator are as follows:
The engine
Alternator
Fuel system
Voltage regulator
Cooling and exhaust system
Lubrication system
Battery charger
Control panel
The main assembly frame or the skid structure of the generator which is sometimes used
for keeping the fuel tank of some of the generators
Importance of studying diesel Generators:
Engr. Bangate emphasized the Economic Significance of Diesel Generators in the
Philippines. According to him, those who are in the generator business, those whose work
is directly involved in generators whether it is in sales operations or maintenance must
look forward to this chance. Correspondent to research and Market the 2021 value of the
Philippines diesel Generator Market was estimated up to millions and is expected to
witness a compound annual growth rate to reach higher by 2030 the biggest driver of DG
set sales in the country is the huge gap in demand And supply of electricity for instance
in Luzon which is inhabited by a lot of people, 11,260 megawatts of energy were supplied
in June 2021 against a pick demand of 11,977 megawatts so we had a power shortage.
Some issues often lead to power outages which can be made worse by natural calamities
as we already know the Philippines sits in the Pacific Ring of Fire which leads to a high
frequency of earthquakes and volcanic eruptions as well as typhoons. Moreover, the
Philippines is A developing country that lags in several essential utilities such as portable
water, the water supply infrastructure is being expanded in the central Luzon region which
will create a strong need for gen sets during construction and for the operations of the
facility. Now Civic commercials and residential spaces are being constructed also in the
Philippines on a massive scale to address the rapid urbanization in the country which will
drive the sale of gen sets during the construction and for diesel-electric since most
construction sites are not connected to the grid they require alternative sources of power
hence the growing construction industry is propelling the requirement for electricity to
operate power tools which is often met by diesel generators.
Great potential for the diesel generator industry in the Philippines
In the coming days, the usage of generators in the event of power failure from the utility
buildings relies on backup power both for the safety and health of the public as well as
the protection of important business assets that cannot be lost during a power outage.
Unexpected disasters often disrupt the power of commercial, industrial, and residential
infrastructures so we use alternative power to ultimately save lives during the event of a
crisis or calamity. Power loss can create a significant economic impact, the longer a
business is without power the greater the economic loss so when this unexpected
situation occurs backup power provides a source to support the equipment loads via a
diesel generator. This is how critical the function of a diesel generator is. This is the
reason why we need to understand how it functions to understand the controls of the
protections are applied to both the prime mover and the generating unit and most
importantly how to do the proper maintenance of the unit to ensure its Reliability
Generator
The principle of generator control operation. In a diesel generator, we control the engine,
there are two types of control for engine speed we have mechanical electrical control and
we have electronic control. For mechanical control, older generator sets utilize these
control systems Mechanical governor a lot of the new generators do not have this one
anymore. We have the electronic control, newer generator sets use an electronic control
system, this system interfaces and controls the engine and Generator control functions
to provide a constant reliable power source that's part of the engine.
Diesel Generator
The generating unit or the alternator is a crucial component of a diesel generator that
converts the engine's mechanical input the spinning of the shaft into electrical output via
induction. An alternator is constructed out of a rotor that creates alternating electricity by
Producing a magnetic field hence the rotor is regarded as the alternator's
Primary component.
Excitation system
As electrical engineers, we are concerned about the excitation system. The system that
provides field current to the rotor winding of a generator, a well-designed excitation
system provides reliability of operation, stability, and fast transient response. We have
four common types of excitation methods. We have the shunt or self-excited, excitation
boost system or (EBS), the permanent magnet generator (PMG), and the auxiliary
winding regulation excitation principles or the (AREP). However, these four excitation
methods use an automatic voltage regulator or AVR to supply DC output to the Exciter
stator. The exciter rotor AC output is rectified to a DC input for the main generator.
Automatic voltage regulator AVR
A device that maintains the generator's normal voltage at a preset value even when there
are sudden load variations or in the case of Special Operations such as parallel operation
between generators, parallel operation between generators and the grid, and start-up of
some demanding equipment. Every generator requires certain voltage and currents for its
excitation therefore the AVR must be provided according to specific generator
requirements.
This is a shunt excitation method when you rotate the generator there will be a residual
current inside the alternator this residual current gradually develops in the system and it
will provide the necessary input current and voltage into the AVR. It will not work until the
triggering voltage reaches or more than the triggering voltage so if you don't have the
triggering voltage there will be no output, as soon as it reaches the triggering voltage the
AVR will start to operate. As the triggering voltage setting of the AVR is reached an
internal circuitry called a buildup block will be Pro powered up to develop and inject a high
voltage that would send the required voltage for the Exciter winding which is needed by
the Exciter to generate the necessary EMF into the rotor of the exciter winding into the
rotor of the generator it will be converted into a DC into the rotor of the main generator
winding and produce the output we need from the generator and then the cycle continues.
The AVR will be relaxed in that state in idle mode, and it will continue to work according
to its function. Its real function is called an automatic voltage regulator so it has to act
automatically to regulate the voltage when you put the load. When you apply the load,
you are putting stress on the generator which means that the shaft of the engine will be
harder to turn the alternator. The voltage will go down and as soon as our AVR senses
that the voltage goes down to its required level then it will inject More Voltage into the
excited to raise the voltage and maintain the output voltage level of our generator
Four basic excitation methods
Shunt or self- excited a simple and cost-effective design to provide input power to AVR.
It requires no additional components or wiring when problems arise. Troubleshooting is
simplified with fewer components and wiring to validate. There is an innovation made
because there are drawbacks with the previous use of technology. The AVR is impacted
by the load the generator is powering. If a short circuit occurs in the supply to the AVR
the generator will not have an excitation Source. This causes a loss of generator power
output. It can be used on linear loads (constant load) applications that have nonlinear
loads (varying load) and are not recommended for generators with this excitation. The
linear loads and the nonlinear loads, nonlinear loads are those that possess harmonics
because it will draw more current from the generator.
Excitation boost system (EBS)
There is an additional component in EBS compared to the shunt like the excitation boost
control or the (EBC) module, the Excitation Boost generator (EBG). The system allows
for dynamic response less expensive and meets requirements for providing 300% short
circuit current so self-excited because it has the capability of providing 300% Short circuit
current into the system of the generator just in case there is a requirement for that.
Nonlinear loads such as motor starting are improved when compared to shunt or selfexcited methods. Having an additional component means that your generator will be
Longer. If you are putting a standby generator in a building there is a certain space
allocated for backup generators so this type of generator will be longer so you have to
design the room for your backup generator according to this one. Sound attenuation
rooms, will not restrict the flow of air into the generator for cooling but it will reduce the
sound significantly as compared between inside and outside so based on my experience.
If you install an EBS excitation system type generator then you need to design the room
according to the dimensions also you have to consider the dimensions of the generator.
But this excitation system is not recommended for continuous power application it is
intended for emergency or backup power applications because when the generator starts,
the EBS system is then engaged until the operating speed is reached the EBG is still
generating power but the controller does not root it so the EBG or the EBC control module
is connected in parallel to the AVR and the Exciter. The EBC receives the signal from the
AVR when needed, the controller supplies varying levels of excitation current to the
Exciter at levels that depend on the needs of the system. The additional power feed to
the excitation system supports load requirements this allows the generator to start and
recover the excitation voltage.
Permanent magnet
Generator generators equipped with permanent magnets are among the most well-known
separately excited methods a permanent magnet is mounted on the Drive end of the
generator shaft. A clean isolated and uninterrupted three-face waveform is produced
when the generator shaft is turning. One of the benefits of the generators equipped with
the PMG excitation methods is (1) the excitation field does not collapse allowing for
sustained short-circuit faults to clear. (2) changing loads does not impact the excitation
field. (1) Voltage is created on initial startup and does not depend on remaining
magnetism in the field. (4) During motor start the excitation field does not collapse
because of a lack of AVR supply. The permanent magnet generator that Supply the
needed voltage by the AVR to operate on its peak level.
Auxiliary winding regulation excitation principle (AREP)
Uses range from marine or industrial applications and are more practical in larger
installations. Has a separate excitation field. However, it does not use a component
attached to the drive end of the shaft of the generator. These methods use shaft rotation
and a permanent magnet or generator to supply the additional excitation. Unlike PMG
and EDG, AREP does not have an additional length of the generator. An additional singlephase winding is installed into the stator. As the generator shaft rotates the stator main
winding Supply voltage to the AVR which creates the extra excitation voltage needed
when supplying nonlinear loads. In the generator, we have the engine protection and the
alternator protection. At the start of the presentation, we showed several types of
generator controllers all of those controllers have similar functions to monitor both the
engine and electrical parameters of a normal operation generator unit, and that controller
will react accordingly, to prevent any damage to the unit.
Typical parameters we are trying to Monitor and control
Engine lubrication system Lube oil pressure, Lube oil temperature, oil level alarm,
lubricating oil filter differential pressure, lubricating oil filter differential pressure means
that there is there are sensors that monitor if the filters of our generators are blocked there
are there is a sensor in the inlet and there's another sensor in the outlet the difference in
this uh between these two sensors will tell you whether or not your filter is blocked.
Crankcase pressure in the engine, the oil Mist detector shuts down it detects the density
of the oil proportional to the amount it Photosensors sensors light transmitter density will
be triggered if there's something wrong with the oil mist or level density oil. Metal particle
detection A scratch between the Piston wall and the cylinder wall will reduce the efficiency
of your engine. Engine fuel system fuel pressure, fuel temperature, and fuel filter
differential pressure. The differential pressure is to determine if your filters are blocked
engine combustion air system we monitor the Inlet manifold air temperature, Inlet
manifold air pressure, air cleaner differential pressure, engine cooling system jacket
water temperature, jacket water pressure, aftercooler water temperature, aftercooler
water pressure, expansion tank level alarm, cooling water loss of-flow alarm, sea water
pressure, engine starting air system for those block start air compressor engine
exhaust system exhaust stock temperature, individual cylinder exhaust temperature,
and the exhaust temperature deviation alarm,
Diesel generator maintenance
We have the daily checks, the daily plus startup checks, we have the first maintenance
50 hours or 6 months, schedule maintenance every 250 hours of operation, and we have
the scheduled maintenance every 1,000 hours of operation. We always need to identify
the type of operation of our generators if it is a prime power or standby Power.
The daily checks
Things that we need to check on a generator daily we have to check the engine oil level
Not sure if everyone is doing this one because normally if the generators run smoothly,
we don’t recognize the problem. We have to check the engine oil level, check the whole
lubrication system for any oil leakage, check the whole cooling system for any coolant
leakage, check the coolant level, check the fuel level, check the whole fuel system for any
fuel, and perform general cleaning keep it cool, keep it dry every time.
The daily plus startup checks
Startup checks so you have to repeat the complete daily checks, check the water heater
block, check the anti-freeze/water ratio, check the cleanliness of the generator, and again
check the whole air system for any leakage (hose and clamps), check the color of the
exhaust smoke, check the batteries and their charge levels if this is a backup generator
normally there's an external source for our battery charger if it is Prime Power, of course,
it will take the charging voltage from uh an alternator, check the battery charger and the
charging alternator, check all the pressure-temperature sensors and gauges, check the
settings of the AVR card and Governor card, check the power cable transfer panel and
its connections, check the control panel and Generator set control unit, check the tension
of the B belts, check the screws and holes tightness for assembling and, checking the
vibration isolation rubber.
The first maintenance for 50 hours 6 months
Change the engine Lube oil, change oil filters, change the fuel filters, drain the water
inside the water separator filter, and repeat the daily startup check. Better to follow the
requirement or the recommendation of the manufacturer to prevent damage to the
generator and for us to avail the maximum uh efficiency of our Generators.
Every 800 or 1,000 hours of operation
You have to check the cleanliness of the radiator, check the turbocharger, check the
injector nozzles, check the setting of valve gaps we need to check the setting of the valve
it will completely damage your cylinder head piston so check about the problem with the
valves, check the vibration isolators replace the air filter primary and secondary elements,
and check the radiator coolant now has periodic annual checks, check the hose and
clamps check the whole air system for any leakage, check the whole exhaust system for
any leakage pipes spiral, check the color of the exhaust smoke, clean the fuel tank, check
the batteries and their charges
Maintenance issues on generators
Smokes are an indicator that your generator engine has a problem understand a white
smoke coming out from your engine is a sign that the engine is running hot if the engine
isn't getting enough water for cooling the remaining water will evaporate producing a white
color smoke it could also indicate a water leak in the cylinder head or gasket possible
cause is the engine is too faulty injector system incorrect timing or the engine is
overheating. Gray or blackish or in a diesel engine could indicate several problems
wrong grade of fuel used, following the manufacturer's recommendation. Clogged air
filter, improper timing, overheating engine, leaking oil, and faulty injection system. Blue
Smoke is because of oil being burnt in the cylinders it is the rarest type of smoke
emanating from a diesel engine blue smoke should not be ignored but is common when
starting an engine in cold weather because the oil thins out when it is cold and some could
Escape into the cylinder and burn possibly causes high engine oil levels worn-out piston
rings old valves or cylinders so these are the checkpoints whenever you find blue smoke
coming out from the exhaust of your diesel engine
Conclusion
Understanding the diesel generator, its functions, operations, and the signals it sends to
communicate with us is the way to achieve its full operating and uh service potential. The
webinar provided a valuable platform for industry professionals to enhance their
understanding of essential concepts and best practices in diesel generator management.
By emphasizing the importance of effective control, protection, and maintenance
strategies, the webinar equipped participants with the knowledge and tools necessary to
optimize the performance, reliability, and longevity of diesel generator systems in diverse
operational environments. This event served as a testament to the importance of
continuous learning and knowledge sharing in driving innovation and excellence within
the power generation industry. As participants apply the insights gained from the webinar
in their respective roles, they are poised to make significant contributions toward
advancing the efficiency and sustainability of diesel generator operations worldwide.
Q and A
Does it need to inject current in the winding of the generator if the generator is not used
for one year does it need to inject current in the generator.
The generator if you rotate it will produce a residual current I don't think that there's a
need to inject current into the generator even if it is not been used for quite a while so it
will give you uh the needed current for uh the triggering voltage for the alternator if just in
case you have a shunt generator a shunt type excitation system for the generator so I'm
not very sure I will search about that but I don't think it's needed