How to choose a suitable generator set

Reasonable selection of generator sets

 A generator set is a complete set of mechanical equipment that converts other forms of energy into electrical energy. It consists of a power system, a control system, a silencer system, a shock absorption system, and an exhaust system. It is driven by a water turbine, steam turbine, diesel engine, or other power machinery to move the water flow. The energy generated by air flow, fuel combustion or nuclear fission is converted into mechanical energy and transmitted to the generator, which is then converted into electrical energy by the generator and output to electrical equipment for use. Generators are widely used in industrial and agricultural production, national defense, science and technology and daily life. In recent years, with the advancement of technology, lightweight and portable small generator sets have begun to enter residents' daily lives as a high-quality choice for home emergency power supply and outdoor travel power supply.
feature of product
  The generator set is powered by a diesel engine and is equipped with a well-known brand generator.
Wide range of unit power: 10~4300KW
Performance advantages
Low fuel consumption, low emissions, low noise
   The unit has excellent performance, advanced technology, reliable operation and easy maintenance.
   High voltage regulation accuracy, good dynamic performance, compact structure and long service life
   Maintenance operations are simple, there are few people, and maintenance is easy during standby period.
There are gas turbine generator sets, diesel generator sets, hydroelectric generator sets and wind turbine generator sets on the market. Different types of generator sets have different performance, scope of use, market conditions, etc. Generator sets should be selected reasonably.
  Gas-fired generator sets are generally used for normal load. The fuel used is natural gas, which has a wide output power range, high startup and operation reliability, good power generation quality, small size and light weight, simple maintenance, low low-frequency noise, and low cost. It has the advantages of low cost and environmental protection, but natural gas needs to be obtained locally, and natural gas energy is not distributed over a large area in our country, so the scope of supply is affected. In addition, there are safety risks for less professional users.
  Diesel units are usually used as emergency or backup power sources. The fuel used is diesel, which is a non-renewable resource and is more expensive. However, diesel is more convenient to purchase and store than natural gas. It has large single unit capacity, wide range of use, high thermal efficiency, and low fuel consumption. , quick to start, and mature maintenance technology, so diesel generator sets are most commonly used in the market.
Hydropower generating sets are generally used in various hydropower stations. They have the characteristics of low cost, small size, light weight, simple structure, reliable operation, and easy installation and use. They are suitable for farmers in mountainous areas with hydropower resources to provide power generation equipment such as lighting and televisions. , but it requires abundant water resources.

      Wind turbines use natural energy, are pollution-free, and are renewable energy sources. They are much better than diesel power generation, but they are not as good as diesel generators for emergency use. Wind turbines are not considered backup power sources, but they can be used for long periods of time. It is generally suitable for use in areas far away from the power grid, pastoral areas, mountainous areas, islands and other areas with rich wind resources. In addition, there is still a big gap between cost and technology compared with traditional thermal power and hydropower, and it also needs the support of national policies. Therefore, it is generally advisable to use diesel generator sets as power generation equipment in engineering projects.

Several factors should be considered when selecting a unit

It mainly includes the mechanical and electrical performance, the purpose of the unit, the capacity and variation range of the load, the operating environment conditions of the unit (including altitude, climate conditions, noise), automation functions, etc. Since diesel generator sets can be used in three situations: regular, backup and emergency, the requirements for diesel generator sets are different for different uses.

Selection of commonly used generator sets

This type of generator set operates all year round and is generally located in areas far away from the power grid (or city power supply) or near industrial and mining enterprises to meet the power needs of construction, production and daily life in these places. In areas with relatively rapid economic development, because the construction of the power grid cannot keep up with the needs of users, common diesel generator sets with short construction cycles are set up to meet the needs of users. This type of generator set generally has a large capacity, provides continuous power supply to non-constant loads, has no limit on continuous operation time, and allows 1 hour of overload power supply time every 12 hours, and the overload capacity is 10% of the rated output power. Due to the long running time and heavy load of this type of unit, the allowable power is adjusted to a lower point relative to the ultimate power of the unit.

(1) Determination of capacity: The output power of the unit in long-term continuous operation can meet the maximum calculated load of the entire project, and the backup unit capacity of the generating unit should be determined according to the importance of the load. The continuous output power of a diesel engine is generally 0.9 times the calibrated power.

(2) Determination of the number of units: The general setting is usually more than 2 units to ensure the continuity of power supply and adapt to changes in the power load curve. Only with a large number of units can the number of generator units invested can be determined according to changes in electrical load, so that the diesel engine can often run under economic load to reduce fuel consumption and power generation costs. The optimal economic operating state of the diesel engine is between 75% and 90% of the rated power. In order to ensure the continuity of power supply, the commonly used units themselves should consider setting up backup units.

(3) Determination of rotational speed: Generally, high-speed units with a rotational speed of 1000~1500 rpm are suitable for civilian use, while low-speed units with a rotational speed of 300~350 rpm are suitable for marine main engines.

(4) Determination of voltage: The determination of the generator output voltage is the same as that of the emergency generator set, which is generally 400V. High-voltage generator sets can be used for projects with large power consumption and long transmission distances.

Selection of backup generator sets

Under normal circumstances, the power required by users is supplied by the city power. When the power supply is interrupted due to power cuts or other reasons, the generator set is set up to ensure the user's basic production and life. This type of generator set is often installed in important power-consuming units such as telecommunications departments, hospitals, industrial and mining enterprises with tight city power supply, airports and television stations. This type of unit remains on standby at all times and can provide continuous power supply to non-constant loads. When the calculated load multiplied by the demand factor and the sum of load capacities is less than the capacity of the emergency diesel generator set, the reserve factor is considered to be 1.2, that is, 1.2 times the calculated capacity is less than the capacity of the emergency diesel generator set. After the mains power outage, the emergency power generator will The unit supplies power to the load. When the calculated load calculated after multiplying the sum of load capacities by the demand coefficient is greater than the capacity of a single emergency diesel generator set, two automated generator sets of the same model, capacity, and similar voltage and speed regulation characteristics can be selected. After the mains power is outage, one or two units will supply power to domestic and commercial electricity; when the mains power is outage and a fire breaks out, two units will supply power to the fire-fighting load to facilitate firefighting.

Emergency generator selection

For electrical equipment that will cause large losses or personal accidents due to sudden interruption of mains power, emergency generator sets are often set up to provide emergency power supply to these equipment, such as fire protection systems in high-rise buildings, evacuation lighting, elevators, control systems of automated production lines, and important communication systems. As well as medical equipment that is performing important surgeries on patients. This type of unit should be able to quickly start operation when the mains power is suddenly interrupted, and provide stable AC power to the load in a short time to ensure timely power supply to the load. This type of unit requires a high degree of automation. Emergency generators should generally be high-speed, supercharged, low fuel consumption, and of the same capacity. The high-speed supercharged diesel engine has a large single unit capacity and occupies a small space; the diesel engine should be equipped with an electronic or hydraulic speed regulating device, which has better speed regulating performance; the generator should be a synchronous motor equipped with a brushless excitation or phase compound excitation device, which is more reliable and prevents faults. The efficiency is low, and maintenance and repair are more convenient; when the capacity of a single air conditioner or the capacity of the motor in the primary load is large, a generator set with third harmonic excitation should be selected; the unit is assembled on a common chassis with a shock absorber; smoke exhaust A muffler should be installed at the pipe outlet to reduce the impact of noise on the surrounding environment. (1) Determination of capacity: The emergency generator set is used for emergency purposes and is often in a standby emergency starting state. The continuous operation time is not long, generally not more than 8 hours, so the capacity can be determined according to "standby power". The capacity of the emergency diesel generator set is determined based on the sum of the capacities of the first-level loads (excluding the reserve capacity), considering the corrected unit capacity and being able to meet the starting requirements of the largest motor in the first-level load. Emergency generators generally use three-phase AC synchronous generators with a calibrated output voltage of 400V. (2) Determination of the number of units: Generally, one generator set with automation, speed of 1000~1500 rpm, brushless excitation, 400/230V, three-phase four-wire with control panel, charging and discharging equipment and a shared chassis is selected. A common chassis with a daily fuel tank can be required to reduce pipelines and occupied area. In addition, for reliability reasons, two units can be connected in parallel for power supply. The number of generator sets for emergency use should generally not exceed 3. When multiple units are selected, the units should try to use complete sets of equipment with the same model, capacity, and similar pressure and speed regulation characteristics. The properties of the fuel used should be consistent to facilitate maintenance and sharing of spare parts.
Diesel generator set is a power supply equipment that uses a diesel engine as the prime mover to drive a synchronous generator to generate electricity. This is a power generation device that starts quickly, is easy to operate and maintain, has low investment, and has strong adaptability to the environment. Diesel generator sets have the advantages of stable power supply, low investment, and easy operation. They are widely used in various fields of modern large-scale industrial construction, and their market has good room for development.
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