Design Diesel Generator Room for Optimum Performance

1. Determination of diesel generator room: Considering the air intake, exhaust and smoke exhaust of the diesel generator set, the machine room is preferably located in the first floor if possible. However, the functions of high-rise buildings are more complex, and the utilization rate of the area is high, especially the first floor, which is often used for external business, and is a golden area that is difficult to occupy. Therefore, the generator room is generally located in the underground floor of the basement, and should not be located on the second floor or below. At this time, it is very important to solve the problem of ventilation, moisture proof, smoke exhaustion, noise reduction and vibration reduction of the unit. It should be handled well in the design.

Pay attention to the following points when selecting the site of the machine room:

a. It should not be located in a room without an external wall, creating favorable conditions for the hot air duct and the exhaust pipe to extend outside;

b. Try to avoid the main entrance, facade and other parts of the building, so as to avoid the impact of smoke exhaust and air exhaust.

c. Pay attention to the impact of noise on the environment;

d. It should be close to the substation of the building, which is convenient for wiring, reducing power loss and facilitating operation management;

e. It should not be located directly below the toilet, bathroom or other places where water is often accumulated.

2. Layout of equipment in the machine room: The equipment layout shall be based on the unit capacity and number of units, and shall be compact, economical and reasonable, safe and easy to maintain.

When there is only one unit in the generator room, if the unit capacity is 500kW or less, there is generally no control room. At this time, the power distribution screen and control panel are conveniently arranged on the generator end or the generator side. The requirements for its operation and maintenance channel are that the screen front distance from the generator end should not be less than 2m, and the screen front distance from the generator side should not be less than 1.5m.

For multiple units with a single unit capacity of 500 kW and above, a control room should be provided taking into account the convenience of operation and maintenance, management and centralized control. Generally, the generator control panel, the unit operating platform, the power control (screen) station, and the lighting distribution box are placed in the control room. The layout of the control room is the same as the technical requirements of the layout of the low voltage distribution room.

In the machine room, the unit should be arranged horizontally (vertically), so that the center line of the unit is perpendicular to the central axis of the machine room, easy to operate and manage, short in pipeline and compact in layout. When the generator room is placed adjacent to the control and power distribution room, the generator outlet end should be arranged near the control and power distribution room.

3. Selection and laying of power distribution wires in the machine room: power cables or insulated wires should be selected according to the wet environment in the diesel generator room; the lead wires from the generator to the power distribution screen should be copper core cables or closed bus bars; strong electric control measurement lines and excitation lines should be the copper core control cable or the copper core wire; the control wiring, the excitation wiring and the power wiring should be laid underground or laid along the cable trench, and the excitation line and the main line can be worn in the same pipe when the steel pipe is used for power distribution. The fixed lighting of the diesel generator room shall be connected to the emergency power supply.

4. Grounding of the machine room: Three types of grounding are generally applied to the diesel generator room:

a. working grounding: grounding of the generator neutral point;

b. protective grounding: grounding of the metal shell with normal electrical equipment without electricity;

c. anti-static grounding: grounding of the fuel system equipment and pipeline.

Various groundings can share the grounding device with other groundings of the building, ie, a joint grounding mode.

5. Storage of fuel: there should be a daily fuel tank for 8 hours of continuous operation in the generator room or in the oil storage room. However, when the oil volume exceeds 100L, it should be placed in the special oil storage room with a fireproof partition wall in the machine room.

6. Civil construction conditions of the machine room: In the civil design of the machine room, the electrical designer must provide civil construction conditions to the civil engineering designer. The contents of civil construction conditions generally have the following points:

a. The height, length and width of the machine room must meet the requirements of the unit. For small units, if the fuel tank, the electric control box and the unit belong to the same whole, the center line of the unit and the central axis of the machine room coincide, there should be 1.5m inspection and maintenance channel between the unit and the wall, and the radiator should be as close as possible to the hot air outlet shutter. In this way, the required size of the length, width and height of the generator room can be calculated.

b. To keep the equipment in and out of the door and the on-duty personnel to enter and go out, and the equipment in and out to ensure that the unit can push out. If the conditions are limited, the door that the equipment enters and exits can also open the small door for personnel to enter and exit; in the place where the radiator of the diesel engine is used, leave hot air exhaust shutter. If the overall air-cooled generating set is not used, leave a reserved hole for the cooling water pipe to pass through the floor.

c. According to the height of the unit and the direction of the smoke exhaust, the exhaust pipe channel casing is to be embedded on the wall;

d. According to the weight of the unit, the civil construction should do the corresponding foundation, and according to the size of the unit chassis, but also make the corresponding base, reserve the hole of the buried angle screw;

e. According to the position of the inlet and outlet line and the electric control box, set the cable trench or embedded pipe;

f. The inlet and outlet air of the engine room should not be placed on the same wall to avoid short-circuiting of the airflow and affecting the heat dissipation effect. However, if there is difficulty, the air outlet should be at the upper part and the air inlet should be at the lower part, and the distance between the two should be more than 2m. The area of the air outlet should not be less than 1.5 times the area of the radiator of the diesel engine; the area of the air inlet should not be less than 1.8 times the area of the radiator of the diesel engine. In the cold area, attention should be paid to the influence of the air inlet and the air outlet on the temperature of the machine room, so as to avoid the low temperature in the machine room affecting the starting of the unit. The air door can be set at the connection between the tuyere and the outdoor, which is normally closed, and can be automatically turned on when the unit is running.