Important facilities such as national defense projects, communication hubs, radio stations and microwave relay stations shall be equipped with standby diesel generator sets. The electricity for such facilities can be supplied by the municipal power grid at ordinary times. However, after the power failure due to the destruction of the municipal power grid due to earthquake, typhoon, war and other natural disasters or human factors, the set standby generator set shall be started quickly and carried out continuously for a long time, so as to ensure the continuous power supply to the power loads of these important projects. This standby generator set also belongs to the type of common generator set. The continuous working time of common generator units is long, and the load curve changes greatly. The selection of unit capacity, number and type and the control mode of units are different from those of emergency units.
1. Determination of capacity of common diesel generator set
According to the long-term continuous operation of the unit, the output power can meet the z-large calculation load selection of the whole project, and the standby unit capacity of the generator unit shall be determined according to the importance of the load. The continuous output power of diesel engine is generally 0.9 times of the rated power.
2. Determination of the number of common diesel generator sets
The number of common diesel generator sets is usually more than 2 to ensure the continuity of power supply and adapt to the change of power load curve. If there are many units, the number of generator units can be determined according to the change of power load, so that the diesel engine often operates under economic load, so as to reduce fuel consumption and power generation cost. The z-best economic operation state of diesel engine is between 75% – 90% of the rated power. In order to ensure the continuity of power supply, standby units shall be considered for common units. When the unit is overhauled or stopped for inspection, the generator unit can still meet the continuous power supply for important power loads.
3. Control of common diesel generator sets
Common units shall generally be connected in parallel to simplify the main wiring of power distribution, so that the power supply will not be interrupted through parallel operation, load transfer and unit switching during unit start-up and shutdown. The unit shall be equipped with measuring and control devices, and the speed regulation and excitation regulation devices of the unit shall meet the requirements of parallel operation. For the standby generator set supplying power to important loads, automatic diesel generator set should be selected. When the external power supply fails to power off, it can start quickly and automatically to restore the power supply to important loads. The noise in the engine room is very loud when the diesel engine is running, and the automatic unit is easy to be transformed into a generator set with compartment operation and automatic monitoring. When the generator set is in normal operation, the operator does not need to enter the diesel engine room and can monitor the diesel generator set in the control room.
4. Determination of rotating speed of common diesel generator set
In order to reduce wear and increase the service life of the unit, medium and low-speed units with rated speed not greater than 1000r / min should be selected for common generator units, and medium and high-speed units can be selected for standby units. The units of the same power station shall be 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 and different capacities can also be selected. The determination of generator output rated voltage is the same as that of emergency generator set, which is generally 400V. High voltage generator set can be selected for some projects with large power consumption and long transmission distance.
5. Ordering requirements of diesel generator set
After making the above choices, the order of diesel generator set shall generally indicate the following contents:
(1) Model, rated power, rated frequency, rated voltage, rated current, number of phases, power factor and wiring mode of the unit.
(2) Requirements for unit automation function and performance.
(3) Requirements for structure, performance and installation dimensions of diesel engine, generator and control panel.
(4) Requirements for parallel operation of units: if multiple units are purchased at the same time, whether parallel operation is required. If parallel operation is required, whether measuring instruments and devices required for parallel operation shall also be provided.
(5) Requirements for auxiliary equipment of the unit: many domestic manufacturers also count the cooling water tank (radiator), fuel tank, exhaust muffler, battery, etc. as auxiliary equipment, and are allowed to put forward some requirements for installation when ordering.
Jiangsu Meao Power Technology Co., Ltd. is an important manufacturer of diesel generators. Meiao generator set manufacturers mainly manufacture and sell diesel generator sets with power of 3-3000kw, mobile power station of 24-600kw, marine emergency diesel generator set of 24-800kw, gas generator set, heavy oil generator set and various imported series Special series (trailer, soundbox, mobile lighthouse, container, etc.) diesel generator sets are engaged in generator set maintenance and after-sales service of generator set accessories at the same time.
