Diesel generator set is a kind of power generation equipment with diesel as the main fuel. It uses the diesel engine as the motive force to drive the generator (ie electric ball) to generate electricity, and convert kinetic energy into electrical energy and thermal energy. What are the generator models of diesel generator sets? In addition to the correct selection of the matching model, attention should also be paid to the installation specifications of the diesel generator set, and regular maintenance is required in the later use. Now, come with me to learn about the knowledge of diesel generator sets!
Introduction to diesel generator sets
What is diesel generator set for
Diesel generator set is a kind of power generation equipment, which is widely used in places where the mains power grid cannot be delivered. Sites, such as communications engineering, mining, road construction, forestry, farmland irrigation, field construction and national defense engineering and other departments.
For areas with mains power, it can be used in units that do not allow power outages and require rapid restoration of power supply within a few seconds, such as communications, banks, hotels, airports and other important departments. It can be used as an emergency backup power supply. The mains power failure can quickly provide a stable AC power supply.
What is the diesel generator set?
The diesel generator set consists of the base, diesel engine, base fuel tank, generator set (ie electric ball), control It is composed of the device (plays the role of control and also plays the role of protecting the unit), radiator (air cooling: fan; water cooling: water tank), silent box and other components.
The principle of diesel generator set
The diesel engine drives the generator to run, and converts the energy of diesel into electricity.
In the diesel engine cylinder, the clean air filtered by the air filter is fully mixed with the high-pressure atomized diesel fuel injected by the fuel injection nozzle. Under the upward extrusion of the piston, the volume shrinks and the temperature rises rapidly. high, reaching the ignition point of diesel.
The diesel fuel is ignited, the mixed gas burns violently, the volume expands rapidly, and the piston is pushed down, which is called ‘work’. Each cylinder performs work in a certain order, and the thrust acting on the piston becomes the force that pushes the crankshaft to rotate through the connecting rod, thereby driving the crankshaft to rotate. By installing the brushless synchronous alternator and the crankshaft of the diesel engine coaxially, the rotor of the generator can be driven by the rotation of the diesel engine. Using the principle of ‘electromagnetic induction’, the generator will output an induced electromotive force, and a current can be generated through a closed load loop. .
A series of diesel and generator controls, protection devices and circuits are required to obtain a usable, stable power output.
Is the diesel generator set DC or AC? Diesel generator set is a type of AC power supply equipment in self-provided power stations. [The working principle of generators>>]
Performance level of diesel generator sets
National standard GB/T2820. 1—1997 “Reciprocating internal combustion engine-driven alternator sets” Part 1: use, rating and Clause 7 in Performance specifies four levels of performance for diesel generator sets.
Class G1 performance requirements apply to connected loads whose basic parameters of voltage and frequency only need to be specified. General use such as lighting and other simple electrical loads.
Class G2 requirements apply to loads that have the same requirements for voltage characteristics as the utility power system. When its load changes, there may be temporary but allowable voltage and frequency deviations. Such as lighting systems, pumps and fans.
Class G3 requirements apply to connected equipment with stringent requirements on frequency, voltage and waveform characteristics. Such as radio communications and thyristor rectifier controlled loads.
Class G4 requirements apply to loads with particularly stringent requirements on frequency, voltage and waveform characteristics. Such as data processing equipment or grating system.
The difference between diesel generator sets and gasoline generator sets
The fuel is different: One is diesel and the other is gasoline.
Different size: The diesel generator set is relatively large in size, and the cooling method is mainly water cooling. The gasoline generator set is smaller in size and mainly air-cooled.
Different power: The output power of diesel generator sets is larger than that of gasoline generator sets, and the range coverage is also large. The power of diesel generator sets can reach 2000kw.
Different types of ignition:In the cylinder of a gasoline engine, the mixture of fuel and air is ignited by a spark plug. In a diesel engine, the mixture is ignited using the heat from compression.
Classification of diesel generator sets
What types of diesel generator sets are there? Diesel generator sets can be divided into basic type, self-starting type and microcomputer automatic control type according to their automation functions. According to the classification of different uses, it can be divided into standby generator sets, common generator sets, combat standby generator sets and emergency generator sets.
The generator type of diesel generator set
In order to facilitate production management and use, the national standard GB2819 has uniformly stipulated the model compilation method of diesel generator set. The model arrangement and symbol meaning of the unit are as follows:
The rated power (KW) output by the unit is represented by numbers.
The type of output current of the unit: G—AC power frequency; P—AC intermediate frequency; S—AC dual frequency; Z DC current.
The type of unit: F—land use; FC—marine use; Q—automobile power station; T—trailer (trailer) vehicle.
The control characteristics of the unit: manual (ordinary type) in absence; Z-automation; S-low noise; SZ-low noise automation.
Design serial number, represented by numbers.
Variant code, expressed in numbers.
Environmental characteristics: Absence is common type; TH is humid tropical type.
Note: Some diesel generator sets have different meanings from the above models, especially the imported or joint venture diesel generator sets are determined by the generator set themselves.
Diesel generator set purchase
Determination of diesel generator set capacity
According to the long-term continuous operation of the unit, the output power can meet the maximum calculation load of the whole project, and it should be Determine the standby unit capacity of the generator set according to the importance of the load. The continuous output power of the diesel engine is generally 0.9 times the rated power.
Determination of the number of diesel generator sets
The number of diesel generator sets is usually set to more than 2 to ensure the continuity of power supply and adapt to the power load changes in the curve. Only when the number of generator sets is large can the number of generator sets to be put into operation can be determined according to the change of electricity load, so that the diesel engine often runs under the economic load, so as to reduce the fuel consumption rate and the cost of power generation. The best economical operating state of the diesel engine is between 75%-90% of the rated power. In order to ensure the continuity of power supply, the common unit itself should consider setting up a standby unit, so that the generator unit can still meet the uninterrupted and continuous power supply to the important power load when the unit is faulty repaired or stopped for inspection.
Determination of the speed of diesel generator set
In order to reduce wear and increase the service life of the generator set, the generator set should choose a medium whose rated speed is not more than 1000r/min. , Low-speed units, and its backup units can choose medium and high-speed units. Units of the same power station should use units of the same model and capacity so as to use the same spare parts and facilitate maintenance and management. For projects with large load changes, units of the same series with different capacities can also be selected.
The determination of generator output calibration voltage is the same as that of emergency generator sets, generally 400V. High-voltage generator sets can be selected for projects with large power consumption and long transmission distance.
Diesel Generator Set Installation Specifications
Ventilation
Air Inlet: According to the capacity of the diesel generator set, the manufacturer gives the air inlet size requirements, and Party A should reserve the air inlet during construction.
Air outlet: According to the capacity of the diesel generator set, the size of the air outlet can be determined, and Party A shall reserve the air outlet during the civil construction.
Smoke Exhaust
Smoke must be exhausted directly outdoors by a properly designed exhaust system fitted with a random exhaust muffler, piped The outer ends should be cut at a 60-degree angle to the horizontal, or fitted with a rain or snow hood system.
Foundation and fixation
According to the capacity of the diesel generator set, the unit gives the corresponding foundation size to meet the load requirements of the unit during normal operation, and the foundation requirement is concrete ground.
The alternator and engine are accurately installed on the steel frame of the whole generator. Therefore, only high-quality expansion bolts need to be fixed on a good foundation when installing the generator.
Diesel generator set maintenance
How often should the diesel generator set be maintained? I suggest that “three-level maintenance” should be carried out on the generator every half a month, counting 4 hours, trial running for 15 minutes, and recording the relevant parameters of the generator when it is working.
Checked according to the regulations, the smoke exhaust system is unblocked, the ventilation system, exhaust and supply fans are in good condition, the air volume is unblocked, the lighting in the computer room is in good condition, and the emergency lights are in good condition.
Check the liquid level of the battery according to the specified time. If the liquid level is not enough, add electrolyte, measure the specific gravity and charge it in time, and make a record.
Remove the air, oil, diesel, and gasoline filters according to the specified time, clean them with dust, and check that the oil is turbid and should be replaced if it deteriorates.
Replace the cooling water of the water tank at the specified time, and measure the insulation resistance of the generator.
Clean the floor and walls of the machine room according to the specified time, so that the unit is free of oil pollution and leakage.
It is operated, operated and maintained by professional technicians.
Troubleshooting of diesel generator sets
Comparison method: In the electrical circuit, if there is a problem with a certain component (such as resistance, capacitor, etc.), you can replace it with a good component and connect it to the circuit If the fault is eliminated, the suspicion is correct.
Verification method: For example, if it is suspected that the cylinder liner is seriously worn, which is caused by poor compression of a certain cylinder, a little oil (about 4~5g) can be poured into the cylinder. If the compression force increases , then the suspicion is true. Another example is that the diesel engine emits black smoke, and it is suspected that the fuel supply is too large. You can also tentatively reduce the fuel supply to verify whether the suspicion is true. When adopting exploratory measures, the principle of “less disassembly” should be followed, and disassembly of the assembly should be avoided.
Isolation method: When analyzing engine failures, the cylinder deactivation method is commonly used, that is, the oil supply to a cylinder of a multi-cylinder engine is stopped in turn, so as to check the cylinder, or according to The change of the fault phenomenon, to distinguish whether the fault is local or universal. For example, it is found that the exhaust gas intermittently emits black smoke. After stopping the work of a certain cylinder, the fault phenomenon disappears, indicating that the fault is located in this cylinder, and the cause of the fault should be further analyzed and found; if each cylinder is disconnected, If there is no obvious change in the fault phenomenon, it indicates that the fault is not a fault of individual cylinders, and the reasons that affect the work of each cylinder should be found.
Shifting method: If the internal combustion engine is faulty, the fault phenomenon may change at the moment of increasing or decreasing the speed of the internal combustion engine. When observing the fault phenomenon, the appropriate speed should be selected to make the fault phenomenon more prominent. Generally speaking, low-speed operation is often used, because the internal combustion engine rotates at a low speed and the failure phenomenon lasts for a long time, which is easy to observe. For example, the knocking sound of the valve mechanism of the internal combustion engine caused by the excessive valve clearance can be quickly eliminated by this method.
Buy.com editor reminds us to minimize disassembly when analyzing diesel generator set failures. Blindly dismantling the unit, or dismantling it easily due to confusion and luck will not only prolong the troubleshooting time and delay the use, but may also cause undue damage or cause new failures.
