What problems should enterprises pay attention to when purchasing diesel generators? Diesel generators are widely used in telecommunications, financial departments, hospitals, schools, commercial departments, industrial and mining enterprises and other special purposes of independent power supply. Enterprises must have their own standards in purchasing diesel generators.
1. the performance and quality of purchased diesel generators must comply with the relevant standard requirements.
The selection and purchase of communication diesel generator set must meet the requirements stipulated in class G3 or G4 in GB2820-1997. At the same time, it is also required to meet the requirements of the 24 performance indicators stipulated in the implementation rules of the quality certification and inspection of the communication diesel generating set. It is also necessary to pass the quality supervision and inspection of the communication power equipment set up by the Chinese industry authorities. The strict examination of the heart.
The selection and purchase of diesel generating sets for military communications must meet the requirements of the GB2820-1997, GJB related standards and the quality testing standards for the communication power equipment formulated by the relevant departments of the army, and the strict inspection of the equipment quality by the relevant organization departments.
2. main factors to be considered for selecting and purchasing diesel generating sets
The main factors that should be considered in the selection and purchase of diesel generator set are mechanical and electrical performance, the use of the unit, load capacity and range of change, automation function and so on.
(1) the use of diesel generator set. The diesel generator set can be used in 3 situations, such as common, standby and emergency. Therefore, different requirements for diesel generating sets are different.
(2) the load capacity of diesel generator set. The capacity of diesel generating unit and the capacity of standby diesel generating unit should be determined by choosing the range of load capacity and load variation according to different uses.
(3) the environmental conditions for the use of diesel generating sets (mainly in terms of altitude and climatic conditions).
(4) selection of diesel generator set
(5) attention should be paid to generators and excitation modes when purchasing diesel generators.
(6) selection of automation functions for diesel generating sets
Performance index folding of diesel generator set
Diesel generating set performance index 1: appearance requirements
(1) the boundary dimensions, installation dimensions and connecting dimensions of diesel generating sets are in conformity with the factory product plans approved by the specified procedures.
(2) the welding of the unit should be soldering firmly, the weld should be uniform, no welding, edge, slag and air hole, etc. the welding slag should be cleaned and clean; the film should be uniform, no obvious cracks and shedding; the coating should be smooth, no leak spot, rust and so on; the fastener of the unit should not be loose.
(3) The electrical installation of diesel generator set should conform to the circuit diagram, and there should be obvious signs that are not easy to fall off at each conductor connection of the unit.
(4) the diesel generator set should have good grounding terminals.
(5) complete signs of diesel generator sets
Diesel generator set performance index 2: insulation resistance and insulation strength
(1) insulation resistance: the insulation resistance between the isolated electrical circuits and the circuits should be greater than 2M
(2) Insulation strength: Each independent electrical circuit of the unit should be able to withstand AC test voltage for 1 min to the ground and between the circuits, without breakdown or flicker.
Circuit voltage test voltage
<100V 750V
More than 100V 1440V
Diesel generating set performance index 3: phase sequence requirements. The phase sequence of the control panel terminals of the diesel generator set should be viewed from left to right or from top to bottom from the front of the control panel.
Diesel generator set performance index 4: diesel generator maintains readiness to run state requirement. The unit shall have a heating device to ensure that the oil temperature and cooling medium temperature of emergency start-up and rapid loading are not less than 15 degrees.
Diesel generator set performance index 5: reliability check for automatic starting power supply and automatic shutdown.
(1) after automatic control or remote control starting instructions, diesel power generation should be automatically activated.
(2) when the unit is automatically started third times, the failure signal should be sent. When a standby unit is set up, the starting system of the program should be able to automatically transfer the starting instruction to another standby unit.
(3) the time from automatic start instruction to load supply should not exceed 3min
(4) after the automatic start-up of the diesel generator, the first load should be no less than 50% of the calibration load.
(5) the unit should be able to stop automatically after the automatic or remote control stop instructions. For the standby units used with the electric power grid, the diesel generator should be able to switch automatically or stop automatically when the power grid is restored to normal. The delay time of the shutdown mode should be in accordance with the regulations of the product technical articles.
Diesel generator set performance index 6: auto start success rate. The success rate of automatic start up is not less than 99%.
Diesel generator set performance index 7: no load voltage setting requirement. The setting range of no-load voltage of the unit is not less than 95%-105% calibration voltage.
Diesel generator set performance index 8: automatic recharge function requirements. The unit should be able to automatically charge the battery to the starting battery.
Diesel generator set performance index 9: automatic protection function requirements. The unit should be short-circuit (not more than 250KW), over-current (not more than 250KW), over-speed, high water temperature cylinder temperature, low oil pressure protection.
Diesel generator set performance index 10: sinusoidal distortion rate of line voltage waveform. Under the condition of no load calibration voltage and calibration frequency, the sinusoidal distortion rate of line voltage waveform is <5%.
Diesel generator set performance index 11: voltage steady state adjustment rate
Less than 250KW >250KW
3% 2%
Diesel generator set performance index 12: voltage transient adjustment rate
Less than 250KW >250KW
20% 15%
Diesel generator set performance index 13: voltage stability time
Less than 250KW >250KW
Less than 2S < < 1.5s
Performance index 14: voltage fluctuation of diesel generator set
Less than 250KW >250kw
0.8% 0.5%
Diesel generator set performance index 15: frequency steady state adjustment rate
Less than 250KW >250kw
3% 3%
Diesel generator set performance index 16: frequency transient adjustment rate
Less than 250KW >250kw
9% 9%
Diesel generator set performance index 17: frequency stabilization time
Less than 250KW >250kw
5S < < 5S
Performance index of diesel generator set 18: frequency fluctuation rate
Less than 250KW >250kw
Less than 0.8% less than 0.5%
Diesel generator set performance index 19: voltage deviation under three phase asymmetrical load
The diesel generator unit should be able to work normally, the maximum or minimum of the line voltage and the average value of the three line voltage, 5% of the three line voltage under the 25% three-phase symmetrical load.
Performance index of diesel generator set 20: noise
The average sound pressure of noise at 1m of diesel engine and generator set is:
Less than 250KW >250KW
Less than 102dB (A) < 108db (A)
Diesel generator set performance index 21: fuel consumption rate. The calibrated power of the unit is 120
Diesel generator set performance index 22: diesel generator consumption rate. The unit calibration power is >40KW, and the unit consumption rate is less than 3.0G/KW.H
Diesel generator set performance index 23: operation test under calibration condition
Under the prescribed working conditions, the unit can run 12h continuously in the calibration condition (including the overload of 10% 1H), and the diesel generating set should have no leakage and air leakage.
Diesel generator set performance 24: remote control, remote signaling and telemetry performance
(1) intelligent unit
The units above 200KW should be intelligent, and their monitoring contents and interface requirements are as follows:
Remote control: turn on / off, emergency stop, switch main standby unit.
(2) Telecommunication: working state (running/stopping), working mode (automatic/manual), main unit, overvoltage, undervoltage, overcurrent, frequency
3. Telemetry: three phase output voltage, three phase output battery voltage and output power.
Interface: there should be a communication interface (RS-232 and RS-485/422) and can provide a complete communication protocol.
(2) non intelligent unit
The non intelligent units of 200KW and below have no remote control, remote communication and telemetry requirements.
