During the construction of diesel generator rooms, some problems that do not meet the specification requirements often occur. If these problems are not solved in time, they may affect the normal operation of the generator room and even bring safety hazards. The following will provide a detailed introduction to common construction issues and the corresponding standard practices.
1. No shock absorption measures were taken for the generator
It is clearly stipulated in the Code for Electrical Design of Civil Buildings (6.1.11) that vibration reduction measures should be taken for the foundation of the unit. When the foundation is set within the main building or in the basement, it is necessary to prevent resonance with the building. However, in actual construction, some generators did not take effective shock absorption measures.
Basic type selection: For places where the requirements for vibration and noise are not strict, reinforced concrete foundations can be used, which can be directly cast on the concrete surface. If the surrounding buildings are in noise-sensitive areas, to reduce the impact of vibration noise on the buildings, isolation and vibration reduction foundations should be adopted, and there should be no rigid connection between the foundation and the machine room.
Shock absorber selection: For smaller power base generators, an integrated built-in rubber shock absorber is used between the generator and the base. If the generator set does not adopt an integrated built-in shock absorber, steel spring shock absorbers should be used during installation.
2.The unit has not taken measures to prevent oil splashing
When diesel engines are in operation, there may be oil splashing problems, but some machine rooms have not taken effective measures to prevent oil splashing. The standards stipulate that the foundation of diesel engines should be equipped with oil-proof facilities, and oil drainage trenches can be set up. There should be a 0.3% slope and drainage measures in the machine room, pipe trench and cable trench. However, this is often overlooked in actual construction.
Ground treatment: The generator foundation and the interior of the machine room, as well as the floor of the machine room, should be coated with oil-proof and anti-oil stain floor paint, and a slope of 0.3% should be set to facilitate the smooth discharge of oil stains.
Oil trough setting: A 10-centimeter oil trough should be set around the foundation. Oil pipelines should be laid in dedicated trenches, and fine sand should be filled in the trenches to prevent oil from flowing away.
3. Unlimited measures for using ordinary rubber shock-absorbing pads
The surface of ordinary rubber shock-absorbing pads is flat, which is different from SD rubber shock-absorbing pads with corrugated types in different directions. When using ordinary rubber shock-absorbing pads, if limit devices are not installed, the unit may experience horizontal displacement, affecting the normal operation of the equipment.
Limit device setting: Set limit measures to prevent horizontal displacement of the unit at the four corners or four sides of the unit.
Selection of shock absorbers: SD rubber shock absorbers with corrugated types in different directions can be used, or shock absorbers with horizontal limit measures can be used to avoid the installation of additional limit devices.
4. The neutral point of the generator is ungrounded
In the electrical design standards for civil buildings, there are clear requirements for the grounding of the neutral point of generators of 1000 volts and below. However, in actual construction, there are cases where the neutral point of the generator is not grounded or the grounding does not meet the requirements. When there is only a single unit, the neutral point of the generator should be directly grounded, and the grounding form of the unit should be consistent with that of the low-voltage distribution system. When multiple units are operating in parallel, the neutral point of each unit should be grounded through a knife switch or contactor. Meanwhile, the Code for Acceptance of Construction Quality of Building Electrical Engineering stipulates that the neutral point, grounding connection method and grounding resistance value in the generator should comply with the design requirements, and the anti-loosening parts of the grounding bolts should be complete and marked.
Standard practice: Both the casing and the neutral point of the low-voltage generator must be grounded. The neutral wire N terminal in the generator junction box should be directly connected to the common grounding conductor or connected through a knife switch as designed to ensure that the grounding complies with the specification requirements.
5. Fuel tanks and ventilation pipes are set up in buildings that do not meet fire protection requirements
The fuel supply pipelines of diesel generators in buildings have strict fire protection requirements. However, in some construction projects, the oil pipes in the oil storage room were not sealed, the vent pipes were not equipped with breather valves with flame arrestors, and no facilities to prevent oil leakage were set up at the bottom of the oil tank.
Fuel tank setup: The fuel tank should be airtight and equipped with a vent pipe leading to the outside. A breather valve with a flame arrester should be installed on the vent pipe. At the same time, set up thresholds, and the height of the thresholds should ensure that oil leakage does not flow out of the oil storage room.
Ground treatment: Lay fine sand or other oil collection measures on the ground at the bottom of the fuel tank to prevent the oil from scattering and causing a fire.
6.The fuel equipment pipelines were not equipped with anti-static grounding
Anti-static grounding measures should be taken for the equipment and pipelines of the fuel system, but in actual construction, it is often the case that they are not set up or are set up in a way that does not meet the requirements.
Grounding connection: The fuel tank is connected to the common grounding conductor, the oil pipeline is connected to the common grounding conductor, and a grounding jumper is made at the pipe fitting valve.
Resistance value requirement: According to the quality acceptance code for industrial metal pipeline construction, for pipelines with static grounding requirements, the resistance value between each pair of flanges or other joints should be less than or equal to 0.03Ω. The Code for Design of Lightning Protection of Buildings stipulates that when the transition resistance at the connection points of elbows, valves, flanges, etc. is greater than 0.03Ω, metal wires should be used for bridging at the connection points. For flange discs with no less than five bolts connected, bridging is not necessary in non-corrosive environments.
During the construction of the diesel generator room, operations must be carried out strictly in accordance with the specification requirements to ensure that each link meets the standards, so as to guarantee the safe and stable operation of the generator room.