In order to ensure the safe operation of diesel generators, the diesel generator set must be grounded in accordance with the requirements of electrical equipment installation regulations, national standards and other current standard documents. Jiangsu Starlight Electricity Equipments Co.,Ltd. reminds you that the implementation of these measures is necessary to prevent possible electric shocks to maintenance personnel and to prevent emergencies. In fact, several different schemes have been adopted.
Diesel generator grounding circuit.
The supplementary equipment required for the diesel generator to ensure its work is an electrical device with an output voltage of no more than 1000. The electrical device works in a power supply system with direct grounding and insulated neutral wires. Therefore, in practice, the neutral line of the second pillar can be implemented in one of the following ways.
1. For devices that operate completely independently, an insulated neutral wire is allowed.
2. When operating in the standby state of the central network with a directly grounded neutral line, the device neutral line is connected to the grounding device.
In the second case, the diesel generator is grounded by one of the following circuits:
1. IT--In this system, the neutral line of the device is insulated, and the exposed conductive part is additionally grounded.
2.TT--Adopt independent circuit or layout of building foundation with booster station, the neutral point of the power supply is directly grounded, and the unit is grounded.
3. TN--This system is used for networks that use directly grounded neutral wires. In this solution, all exposed conductive parts are connected to the direct grounding neutral line of the generator through the protective neutral line. In fact, with the TN-C scheme, the working conductor and the protective conductor are combined, the TN-S scheme uses a separate circuit, and the TN-C-S scheme uses a combination of the first two schemes in a separate section. The grounding of each standby diesel generator should be completed according to one of the above schemes, otherwise safe operation cannot be guaranteed.
Grounding requirements of electrical equipment installation regulations.
The basic documents that stipulate the grounding of electrical equipment installation procedures require that the following conditions are met when the anti-shock system is installed.
1. The ground loop is a combination of a grounding device (a conductor in direct contact with the ground) and a grounding conductor connected to the equipment.
2. The grounding conductor is connected to the grounding device by welding, while the grounding conductor is connected by bolts. For this reason, the fixture of the equipment cannot be used. The installation of an independent circuit is considered the best solution. However, if the unit is installed in a room with its own circuit, it is allowed to connect to that room.
3. In addition, building foundations and pipelines are allowed to be used as grounding bodies, except for pipe networks used in flammable or explosive environments.
In any case, it is necessary to ensure that the resistance of the grounding device is within 4 ohms. Only in this way can the safety of Dga work be guaranteed.
Comprehensive Grounding Measures for Diesel Generators.
The ground loop of the booster station can be combined with lightning protection. For this, the following tasks need to be completed.
1. Fix two air-termination poles on the opposite wall of the diesel generator, the height of which shall not be less than 1.5 meters.
2. In order to connect the air-termination device with the grounding device, lay the current lead, and its cross-section is determined by calculation.
3. 1 meter around the building, the depth is not less than 0.5~0.7 meters, and the main ground loop is laid with the calculated cross-section metal strip.
4. Install vertical electrodes at the current inducing point connected to the lightning protection device and the protected equipment, and the length is not less than 3 meters.
5. The connection of all components uses special clamps.
This solution can ensure the effective grounding and lightning protection of the booster station, and at the same time occupies the least space, and can be implemented in a small area. For more details, please contact us with email@example.com