Purchase based on diesel generator sets

First, the basis for purchase of diesel generator sets

1 diesel generator sets selected performance and quality must meet the standards

Diesel generators are widely used in telecommunications, finance departments, hospitals, schools, business and other departments, industrial and mining enterprises and residential standby power, military and field operations, shipping and other special purpose vehicles and a separate power supply.

Diesel generator sets as a communication, must meet the GB2820-1997 in the G3 or G4 grade level requirements at the same time and "communication with the diesel generator set network access quality certification testing implementation details" under the 24 performance requirements, but through China's trade authorities have set up communications power supply Quality Supervision and Inspection Center of rigorous testing.

As a military communications diesel generator sets, must meet the GB2820-1997, GJB standards and force departments to develop a "communication power supply quality testing standards" requirement, and to the organization department of the equipment through strict quality inspection.

2 diesel generators should be considered a major factor in choice

Unit selection factors should be considered mainly mechanical and electrical properties, the use of the unit, load capacity and range, automated functions.
(1) unit uses. As the diesel generator can be used commonly, three kinds of backup and emergency situations. Therefore, use of diesel generator sets of different requirements there is a distinction.
(2) load capacity. Selection should be based on different uses of load capacity and load range, determine the stand-alone diesel generation set of machine capacity and backup diesel generator capacity.
(3) units using environmental conditions (mainly refers to the altitude and climatic conditions)
(4) the choice of diesel generators
(5) the choice of generator and excitation mode
(6) diesel generator automation options

Second, the optional standard diesel generator sets

> specified requirements of 24 performance indicators: ">Communication with the diesel generator set network access quality certification testing implementation details>> specified requirements of 24 performance indicators:

1 Appearance requirements
(1) diesel generator set limits size, mounting dimensions and connection dimensions are in line with prescribed procedures approved by the factory product design
(2) The unit should be firmly welded, the weld should be uniform, no welded wear, undercut, slag and porosity and other defects, welding slag, welding flux should be cleaned; film should be uniform, no crack and fall off; coating should be smooth , seamless plated spots, corrosion and other phenomena; unit should not be loose fasteners.
(3) diesel generator electrical installation should meet the circuit, each unit should be easy to fall off the wire connections clearly marked.
(4) diesel generator should be a good grounding terminal.
(5) diesel generators and complete signage content

2. Insulation resistance and dielectric strength
(1) Insulation resistance: the independent circuit electrical circuit between the ground and the insulation resistance should be greater than 2M
(2) Dielectric strength: an independent unit of the electrical circuit between the ground and the circuit should be able to withstand the test voltage AC 1min, there should be no breakdown or flicker.

Circuit voltage test voltage
less than 100V 750V
More than equal 100V 1440V

3 phase sequence requirements. Diesel generator control panel terminals of the phase sequence from the front control panel should be from left to right or from top to bottom order.

4 diesel generators to maintain ready for operation requirements. Unit should have a heating device, to ensure that its emergency starts and fast loading of the oil temperature, coolant temperature not lower than 15 ℿ/STRONG>

5. Automatically starts and automatic shutdown of power supply reliability check
(1) then self-control or remote start command, diesel power generation should be able to start automatically.
(2) The unit automatically starts after the 3rd failure, failed to start signal to be sent; equipped with reserve units, the program should be able to start the system automatically starts the backup command is passed to another unit.
(3) from the automatic start command is issued to the load time should be no more than 3min
(4) diesel generator starts automatically after the success of the first load, shall not be less than 50% of the calibration load.
(5) then self-control or remote shutdown command, the unit should be able to automatically shut down; and electricity for the grid and use the backup unit, when the grid is back to normal, diesel generators should be able to automatically switch or automatic shutdown, the shutdown delay shutdown mode time should be consistent with product technical requirements.

6, self-starting success rate. Automatically start the success rate of not less than 99%.

7, no-load voltage tuning range requirements. Unit load voltage setting range is not less than 95% -105% calibration voltage.

8, automatic replenishment functional requirements. Unit should be able to automatically start charging the battery.

9, automatic protection requirements. Unit should phase, short circuit (less than 250KW), over current (less than 250KW), too fast, high-temperature cylinder temperature, oil pressure protection.

10, line voltage sine wave distortion. In the no-load voltage calibration, calibration frequency, the sinusoidal line voltage waveform distortion rate <5%.

11 Steady state voltage regulation
Less  equal 250KW> 250KW
3% 2%

12, transient voltage regulation
Less  equal 250KW> 250KW
20% 15%

13, the voltage settling time
Less  equal 250KW> 250KW
Less  equal 2s Less  equal 1.5s

14, voltage fluctuation rate
Less  equal 250kw> 250kw
0.8% 0.5%

15, steady-state frequency regulation
Less  equal 250kw> 250kw
3% 3%

16, the frequency of transient regulation
Less  equal 250kw> 250kw
9% 9%

17, the frequency settling time
Less  equal 250kw> 250kw
5s Less  equal 5s

18, the frequency volatility
Less  equal 250kw> 250kw
Less  equal 0.8% Less  equal 0.5%

19, three-phase unbalanced load voltage deviation
Diesel generator set at 25% of the three-phase symmetrical load, in any phase calibration phase power plus 25% of resistive load, the unit should be able to work, the maximum or minimum line voltage and three-wire voltage average of 5%.

20, noise
Diesel engine and generator unit away from the noise sound pressure at 1m average:
Less  equal 250KW> 250KW
Less  equal 102db (A) Less  equal 108db (A)
Noise standards:
Sleep <45db ambient noise in residential areas during the day can not exc, , eed 50 dB at night should be less than 45 (40) dB
Work <65 db average person in the 40 decibel sound can be maintained under the normal reaction and attention, but at 50 decibels or more of the environment, will be a long time, hearing loss, emotional irritability, and even debilitating neurological and so on.
Listening to music more than 80 decibels noise 80db children live in an environment, resulting in up to 50% deaf person, noise level below 80 decibels only to maintain the long-term work will not be deaf for 40 years; at 100 dB, only 60% of people not deaf. If people are living in an environment where more than 80 decibels, can cause emotional irritability, hearing loss. Noise on the role of the human central nervous system damage, and can induce cardiovascular diseases, in strong noise environment, eating, gastrointestinal contraction of the capillaries occurs, digestive secretion and gastrointestinal motility will be reduced, so that normal blood supply has been damaged. Noise will result in a strong abnormal pregnancy, child mental retardation. Therefore, to minimize the daily life of noise sources and propagation.
85 db the following can cause a slight hearing loss;
85 db -90 decibels can cause noise-induced hearing loss a few people;
90-100 decibels can cause a certain amount of noise-induced hearing loss;
100 db or more, will result in a considerable number of noise-induced hearing loss, these are chronic noise-induced hearing loss.
105 db above --- 5 minutes schizophrenia

21, the fuel consumption rate. Rated power of 120 unit

22, diesel generator consumption. Unit rated power> 40KW, the unit consumption rate Less  equal 3.0G/KW.H

23, run the calibration test conditions
Unit at the required operating conditions (GB2820 in Section 4.2), the unit can be calibrated to the normal conditions of continuous operation 12h (including 10% overload operation 1h), and diesel generator sets should be no leakage and leakage phenomenon.

24, remote control, remote and telemetry performance
(1) intelligence unit
200KW or more units shall be intelligent, their monitoring of the content and interface requirements are as follows:
1 remote control: on / off, emergency stop, switch the main and backup units.
2 Remote letter: work status (run / stop), work (automatic / manual), the main use of the unit, overvoltage, undervoltage, overcurrent, frequency
3 Telemetry: Three-phase output voltage, three-phase output dynamic battery voltage, output power.
4 interface: should have a communication interface (RS-232 and RS-485/422) and can provide a complete communication protocol.

(2) non-intelligence unit
200KW and below, non-intelligence unit without remote control, remote and telemetry requirements.

Third, the choice of the emergency diesel generators

Emergency diesel generator is mainly used for an important place, in case of emergency or accident immediately after the power outage, emergency generators by the rapid power recovery and extend the period of time. Such as a load of electricity load. There are strict requirements on power-off time of equipment, instruments and computer systems, except with the generator should be located outside the battery or UPS.

The work of the emergency diesel generators have two characteristics:
No. 1 feature is for emergency use, continuous working time is not long, continuous operation is generally only a few hours (Less  equal 12H);
Section 2 is characterized as a backup, emergency generators usually in a wait state shutdown, only when the main power off all the drum barrier, the emergency diesel generators start to run until the supply of emergency power load, when the main power is restored to normal, then switch downtime.

(1) emergency diesel generator to determine the generating capacity

Emergency diesel generator set calibration capacity after 12h by the atmospheric correction calibration capacity, its capacity should be able to meet the total emergency power load calculations, according to the load generating capacity to meet a maximum capacity in a single motor starting requirements for verification . Emergency generator is generally used in three-phase AC synchronous generator, the calibration of the output voltage of 400V

(2) emergency diesel generator sets to determine the number

Multiple backup generators, generally only set up a Taiwan emergency diesel generator sets, from reliability to consider 2 units can also be used in parallel for power. Supply urgently generating units Number of units is generally not more than three. Elected with more than one unit, the unit should be selected models, the same capacity, voltage regulator, speed characteristics similar to the equipment, the nature of fuel used should be the same for maintenance and spare parts sharing. When the supply of urgently generating group 2, the self-starter 2 units should be able to spare each other, that mains power failure, power outage after delay after verifying the issue from the start command, if the first unit for three consecutive times from Failure to start, should send a warning signal and automatically start the first two sets of diesel generators.

(3) the choice of the emergency diesel generator

Emergency units should use high-speed, pressure, low fuel consumption, with the capacity of diesel generator sets. Single large-capacity high-speed turbocharged diesel engine, small footprint; diesel use with electronic or hydraulic control devices, speed performance is better; generator should be used with brushless excitation or phase compound excitation device synchronous motor, a more reliable, fault low maintenance and overhaul is more convenient; when a load capacity in a single air-conditioner or motor capacity is larger, better to use third-harmonic excitation of the generator; machine assembled in a shared chassis with a shock absorber; smoke outlet should be installed muffler to reduce noise on the surrounding environment.

(4) emergency diesel generator set control

Emergency generator set control should be fast from the start and automatic input device. When the main power supply after power failure, emergency unit should be able to recover quickly from the start and power supply, a load to allow time off from ten seconds to tens of seconds, according to specific circumstances. When important projects off the main power supply, the first 3-5S should be over a definite time, to avoid the instantaneous voltage drop and the city grid or BZT closing time, and then issued instructions start the emergency generator set . From the command issued, the crew began to start or speed to be able to take some time with full load. Generally large and medium-sized diesel engines need to process the pre-lubrication and warm-up to ensure that emergency load of oil engine oil pressure, oil temperature, cooling water temperature in line with the conditions of the plant product technology; pre-lubrication and warm-up process can be carried out according to different situations in advance . Such as military communications, the important foreign affairs activities of large hotels, public buildings, large-scale mass activities at night, the hospital for major surgery and other emergency units should be in normal times the pre-lubrication and warm-up state, in order to keep fast start, try to shorten the time power failure .

Emergency unit inputs, in order to reduce the sudden mechanical load and current impact, to meet the power requirements of the case, preferably by the time interval of emergency load rating increase. According to national standards and national military standard, automated self-starting after the success of the unit allows the loading of the first volume are as follows: rated power less than 250KW for those who, for the first time allow the load capacity of not less than 50% of the calibration load; for the calibration of power greater than 250KW who, according to the provisions of plant materials and technical conditions. If the instantaneous voltage drop and the transition process is not strict, generally sudden, or sudden unit unloading of the load should not exceed 70% of the capacity of the unit calibration.

Fourth, the common choice of diesel generator sets

Some of the diesel generator at a certain time or continuously for a long time often need to load commonly used as a power supply, such as generators used generators. Commonly used as a generator unit and the standby unit. Away from the large grid of townships, islands, forest, mining, oil and other regions or industrial and mining enterprises, in order to supply local residents and students living power plant, you need to install diesel generators, these generators usually be uninterrupted.

Defense engineering, communications hub, radio, microwave relay stations and other important facilities should be equipped with backup diesel generators. Such facilities usually available by the electric power grid supply. However, due to earthquakes, typhoons, wars and other natural disasters or man-made factors, the city suffered damage and power outages after the grid has set the standby unit should start promptly, and adhere to long-term continuous manner, to ensure that these important projects for electricity load continuous power supply, standby generators are also part of this common type of generator sets. Used generator sets continue to work long hours, the load curve greater capacity of the units, the number of units, type of choice and control units and emergency units in different ways.

1 used to determine the capacity of diesel generator sets

Long-term continuous operation by the unit output to meet the maximum calculated load the whole project selection, and the load should be based on the importance of backup generators to determine the capacity of the units. Diesel ongoing power output, usually 0.9 times the rated power.

2 sets of diesel generators used to determine the number

Number of units used diesel generator set is usually two or more, in order to ensure continuity of supply and meet the electricity load curve changes. Number of units and more units can only be determined according to the changes in power load of the units into the number of generators, the diesel engine is often in the economic load operation, to reduce fuel consumption, reduce electricity costs. The best economic engine running in rated power between 75% -90%. To ensure continuity of supply, the unit itself should consider setting common standby unit when the unit failure or downtime maintenance inspection, the generator is still important to meet the electricity load for continuous uninterrupted power supply.

3 used to determine the speed diesel generator sets

In order to reduce wear and increase the life of the unit, used generators should use no more than nominal speed of 1000r/min, the low-speed unit, the standby unit can select, high-speed unit. Should use the same power plant units with the model, with the capacity of the unit to use the same spare parts, easy maintenance and management. Load changes of the project, you can also use the same series in different capacity units. Calibration generator output voltage to determine the same with emergency generators, usually 400V, individual power capacity, transmission distance of the project can be used high-pressure turbine.

4 used diesel generator set control

Common units should generally be considered to be parallel in order to simplify the main power distribution wiring, and the unit start, stop rotation of running through and vehicles, transfer of load, switching power supply unit without interruption. Unit should be installed with the unit of measurement and control devices, speed control unit and the excitation-conditioning should be applied in parallel to the requirements of the fish. Significant load on the power of the standby generator set, diesel generator sets should use automated external power supply when the power failure, it can quickly auto-start and restore power to critical loads. Noisy engine room operation, the automated unit compartment to facilitate the transformation of operation, automatic control of generators. When the generator normal, the operator does not have to enter the engine room, in the control room can monitor for diesel generator sets.

Fifth, the order requires diesel generator sets

Make these selections in the diesel generator set shall be marked with the following general order:
(1) unit of the model, rated power, rated frequency, rated voltage, rated current, number of phases, power factor and connection methods.
(2) on the unit automation and performance requirements.
(3) of the diesel engine, generator and control panel of the structure, performance, installation size requirements.
(4) requirements for parallel operation of the unit: To purchase multiple units in parallel asking for, such as the need for parallel, but also suggest the need to provide the necessary measuring instruments and parallel devices.
(5) of the unit ancillary equipment requirements: many domestic manufacturers to cooling water tank (radiator), fuel tank, exhaust muffler, batteries, etc. to be regarded as ancillary equipment, installation of the proposed order would permit certain requirements.

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