Selection of self generating diesel generating set for civil building

In recent years, variable frequency starting device used in building more and more widely, compared with other variable frequency starting starting mode, small starting current and torque, the reactive power impact current, voltage drop caused by the very small, therefore, the author thinks that, when the motor adopts frequency conversion starting, can only consider the use of the computational load to calculate the capacity of the generator, without considering the factors of motor starting.

Project example: a project designed by the author as an example, the construction area of 10000m2, 12 layers, two high-rise, security load mainly for fire load, the maximum capacity of 191kw, a motor for spray pump 37KW, using 80% tap autotransformer starting.

(1) calculation of P=kPj / ETA =1.1 * 191 / 1kw=210.1 kW according to the calculated load

(2) the largest single motor starting to calculate P= (P -Pm) / +PmKCcos M = ETA sigma psi (191 - 37) / 0.85+37 * 6 * 0.64 * 0.4 =238.0 kw

(3) according to the calculation of P=PnKCXd "while starting a motor generator bus allowable voltage drop (1 / E-1)

=37 x 6 x 0.64 * 0.25 (1 / 0.20-1)

=142.08 kw

According to the above calculation, selection of generator should be greater than 238 kW a, so an optional unit of 250kw.

3. unit selection

(a) the number of options when the motor starting capacity to choose the capacity of the wind turbine generator units, not much, because the number of units, unit capacity is small, there may not be able to meet the needs of starting motor. Generally, when the capacity is not more than 800KW, the use of single machine is good. When the capacity is above 800KW, two units should be selected, and the physical parameters of the two units should be the same to facilitate the operation of the unit and the car.

(two) other functional options, emergency standby generator sets for civil buildings should be made of high speed diesel generator sets and brushless automatic excitation devices. The unit should be equipped with fast automatic starting and automatic switching device, and should have three continuous self starting function. Compressed air shall not be used for starting, and the 24V battery will be used as the starting power.