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Commissioning and acceptance requirements for diesel generator sets

May 07, 2022
Before the diesel generator set is officially put into operation, it is very necessary for the generator manufacturer to carry out its height and acceptance. When installing the diesel generator set, consideration should be given to: the load of the foundation, the pedestrian passage and the position of maintenance, the vibration of the unit, and the ventilation. Heat dissipation, exhaust pipe connections, thermal insulation, noise reduction, fuel tank size and location, as well as national and local building, environmental regulations and standards related to them are key factors.
As an emergency backup power source, diesel generator sets play an extensive and important role in various industries in the current society. In order to ensure that users can use them normally, before the diesel generator set is officially put into operation, the generator manufacturer shall conduct high-level and acceptance checks on it. It is very necessary that it can be put into normal use only after strict technical acceptance to ensure that its safety, power characteristics, power quality, noise value and other performance indicators meet the acceptance standards. This article first focuses on explaining the acceptance criteria for the installation quality of diesel generator sets.
 The installation quality of the unit must meet the installation requirements of the diesel generator set. When installing the diesel generator set, consideration should be given to: the load of the foundation, the position of the pedestrian passage and maintenance, the vibration of the unit, ventilation and heat dissipation, the connection of the exhaust pipe, heat insulation, lowering noise, the size and location of the fuel tank, and national and local building, environmental regulations and standards associated with it. During the acceptance of the installation quality of the unit, the acceptance shall be carried out item by item according to the requirements of the installation of the unit and the architectural design of the machine room.
Layout principle of the unit in the engine room
1. The air inlet and exhaust pipes and smoke exhaust pipes should be laid overhead on both sides of the unit against the wall, in a space with a height of more than 2.2m, and the smoke exhaust pipes are generally arranged on the back of the unit.
2. The installation, maintenance and handling passages of the unit should be arranged on the operating surface of the unit in the parallel arrangement of the machine room. In the machine room arranged in parallel, the cylinder is a vertical single-row unit, which is generally arranged at one end of the diesel engine, while for the V-shaped diesel generator set, it is generally arranged at one end of the generator. For a machine room with two parallel rows, the installation, maintenance and handling passages of the units should be arranged between the two rows of units.
3. Cables, cooling water and fuel pipes should be installed on the brackets in the trenches on both sides of the unit, and the net depth of the trenches is generally 0.5~0.8m.
Requirements for the architectural design of the computer room
1. The machine room should have entrances, exits, passages and door holes that are convenient for the transportation of large equipment such as diesel generator sets and control panels, so as to facilitate equipment installation, transportation and repair.
 2. 2~3 lifting hooks should be reserved above the longitudinal center line of the unit, and the height should be able to lift out the piston and connecting rod components of the diesel engine, so as to facilitate the installation and maintenance of the unit.
3. The pipes for laying cables, cooling water and fuel oil in the machine room should have a certain slope to facilitate the removal of accumulated water. The cover plate of the trench should be a steel plate cover plate, a reinforced concrete cover plate or a fire-resistant wood cover plate.
4. For the computer room where the control room is set, there should be an observation hole on the partition wall between the control room and the computer room.
5. For the computer room designed together with the main building, sound insulation and silencing should be carried out.
6. The floor of the machine room should be calendered cement floor, or terrazzo or cylinder brick floor. The floor should be able to prevent oil pollution from infiltrating.
7. Certain shock absorption and isolation measures should be taken between the foundation of the unit and the surrounding ground, as well as between the units, to reduce the damage caused by vibration. The surface of the foundation with the common chassis should be 50~100mm higher than the ground, and anti-oil immersion measures should be adopted. Sewage trenches and floor drains should be provided on the surface of the foundation to remove oil stains on the surface of the foundation.
Installation requirements for stationary units
1. Installation location: The diesel generator set can be installed in the basement, the ground and the roof. The engine room of the diesel generator set should be near the power distribution room for wiring, use and maintenance. However, it should not be too close to the communication room, so as to avoid vibration, noise and pollution generated during the operation of the unit from affecting the communication effect of the communication equipment.
2. Requirements for machine room and foundation construction: The power of the diesel generator set and future expansion should be considered in the construction of the machine room, with a complete water supply and drainage system, and the construction should be firm, safe, and equipped with ventilation and heat dissipation channels. With guaranteed lighting, insulation and fire protection measures. The temperature of the equipment room should be between 10°C (winter) ~ 30°C (summer). It is best to use heating and air-conditioning equipment for heating and cooling of the computer room. For the diesel generator set room in the office area and living area, shock absorption, noise reduction and exhaust purification devices must be used to protect the surrounding environment. The depth, length and width of the foundation should be determined according to the performance indicators such as power and weight of the unit and the soil quality. Generally, the depth is 500~1000mm, and the length and width should not be less than the size of the unit base. The foundation should be well level and have shock absorption capacity. .
3. Fixing of the unit: the fixing bolts of the foot of the diesel generator set should be firmly poured on the concrete foundation, and the embedding of the foot bolts should be flat and firm to facilitate the operation and maintenance of the unit. The arrangement of the equipment should be able to meet the operation, maintenance, lifting and handling of the unit. And minimize the length of the pipeline to avoid pipeline crossing.
Preparation for commissioning
1. Debugging environment check
 The debugging environment should be clean, tidy, free of dust and debris. The exhaust, oil and water pipes of the unit should be unobstructed.
2. Inspection of test equipment
The functional integrity of the test equipment should be carefully checked before the test. For the load used for the test, the starting power supply of the unit, the circuit breaker, etc., it should be checked whether the line connection is reliable, whether the function is in good condition, and whether the various instruments used in the test meet the accuracy and validity period specified by the corresponding test level, and their functions. Is it in good condition.
Be familiar with the product drawings and technical data of the test unit, and be proficient in the test specifications of the unit.
The unit adds coolant, oil, and fuel. Select the appropriate coolant according to different engines and regions, open the radiator cover of the unit and add coolant to the MAX scale of the water tank. Select the appropriate type of lubricating oil, open the engine oil filler and add oil to the engine to the appropriate position.
Quality inspection before unit start-up
Check the appearance quality of the units one by one in the order of radiator, oil engine, control panel, generator, chassis, and power distribution cabinet, including welding quality, wiring quality, three-leakage, component quality and overall quality.
1. Welding quality: The welding of the unit should be firm, the welding seam should be uniform, and there should be no defects such as welding penetration, undercut, slag inclusion and stomata. The welding slag and flux should be cleaned up. and fall off;
 2. Wiring quality: all wirings are in good contact, firm and fastened, with clear signs and correct connections. The electrical installation of the unit should be in accordance with the circuit diagram, and the phase sequence of the terminals of the control panel of the unit should be arranged from left to right or from top to bottom when viewed from the front of the panel. There should be obvious signs that are not easy to fall off at the connection of each line. The signs such as nameplates, direction signs, and grounding signs should be set firmly, the content is clear and accurate, and good grounding terminals should be set. The nameplate of the unit shall include the following:
       a. Unit name;
       h. rated current;
       b. Unit model;
       i. Rated power factor;
       c. Phase number;
       j. Mass (Kg);
       d. Rated speed (r/min);
       k. The name of the manufacturer;
       e. Rated frequency (Hz);
       l. Unit number;
       f. Rated power (KW);
       m. date of manufacture;
       g. Rated voltage (V);
       n. Standard code and number.
Three leakage conditions: the unit should have no oil leakage, water leakage, and air leakage (check after startup);
Quality of parts: diesel engines, generators, control panels, power distribution cabinets and other components and parts should be intact, with no obvious scratches and cracks on the surface, no damage to the control panel instruments, and clean surfaces;
Overall quality: The parts are fixed and connected reliably, and the whole machine has no missing parts, no nuts, washers and other phenomena. There shall be no sundries and metal objects inside the unit, especially in the control panel and power distribution cabinet.
 The minimum distance between exposed conductors of different phases and between conductors and ground in the equipment junction box should meet the insulation requirements of different voltage levels, otherwise insulation protection measures should be taken.
The switchgear, automatic or manual switching device and protection device of the power distribution cabinet have passed the test, and the load test shall be carried out according to the designed self-provided power supply use distribution plan, and the grounding or zero connection of the grounding bare conductor shall be reliable.
Measure insulation resistance Measure the insulation resistance of each independent electrical circuit to ground and between circuits, and measure with a megohmmeter. During measurement, semiconductor devices, capacitors, etc. should be removed, and each switch should be in the ON position. When the megohmmeter indicates stable, read it again, and record the ambient temperature and air relative humidity at the same time. 
Dielectric strength test
This test is to carry out the dielectric strength test of each independent electrical circuit to ground and between circuits. During the test, turn on the power supply and increase the voltage not exceeding 5% of the full value to the full value evenly or in stages. The time for the voltage to increase from the half value to the full value should not be less than 10S. The full value voltage test lasts for 1min. Then start to reduce the voltage, cut off the power after the voltage drops to one-third of the full value, and discharge the tested circuit to the ground. Record the ambient temperature, air relative temperature, atmospheric pressure, and test results should meet the relevant provisions of GB/T2820.
After passing the above test, it can be transferred to the start-up test.
The above is the debugging problem of diesel generator set introduced by JUNVOCH for you. Before the customer unit is officially put into use, the above steps must be strictly debugged. JUNVOCH is a generator set integrating design, supply, commissioning and maintenance of diesel generator sets. Manufacturer, JUNVOCH has always been committed to providing customers with comprehensive and considerate one-stop diesel generator set solutions.