Views: 0 Author: Site Editor Publish Time: 2016-08-05 Origin: Site
As a diesel generator set manufacturer, Haixing Power has a say in the selection and purchase of diesel generator sets. There is a big difference in the selection and purchase of emergency diesel generator sets and commonly used generator sets. Let the staff talk to you about the basis for purchasing diesel generator sets in detail.
Selection of emergency diesel generators
Emergency diesel generators are mainly used in important places. They will be powered out instantly after an emergency or accident outage. They will quickly recover through the emergency generator set and extend the power supply time for a period of time. This type of electrical load is called first-level load. Equipment, instruments and computer systems that have strict requirements on power outage time should be equipped with batteries or UPS power supply in addition to being equipped with generators.
The operation of an emergency diesel generator has two characteristics:
The first feature is that it is used for emergency purposes. The continuous working time is not long and generally only needs to be continuously operated for a few hours (≤12H);
The second feature is to be used as a backup. The emergency generator set is usually in a state of shutdown and waiting. Only when all the main power supply is blocked and powered off will the emergency diesel generator set start and run to supply emergency power load. When the main power supply returns to normal, the shutdown will be switched.
(1) Determination of generator capacity of emergency diesel generator
The calibration capacity of the emergency diesel generator set is the 12-h calibration capacity after being corrected by the atmosphere. Its capacity should be able to meet the total emergency electrical calculation load, and it should be calibrated according to the generator capacity that can meet the starting requirements of a single capacity motor in the first-level load. Emergency generators generally use three-phase AC synchronous generators, and their calibration output voltage is 400V.
(2) Determination of the number of emergency diesel generator sets
When multiple generator sets are backed up, only one emergency diesel generator set is set up. From the perspective of reliability, two units can be selected to supply power in parallel. The number of urgently used generator sets 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, similar pressure and speed regulation characteristics, and the fuel properties used should be consistent for maintenance and shared spare parts. When there are two generator sets for emergency use, the self-starting device should enable the two units to be backup for each other, that is, after the power failure of the mains power supply has been confirmed after delay, a self-starting command will be issued. If the first unit fails to start automatically for three consecutive times, an alarm signal should be issued and the second diesel generator should be started automatically.
(3) Selection of emergency diesel generators
Emergency units should use high-speed, supercharged, low fuel consumption and same capacity diesel generator sets. The single-unit high-speed booster diesel engine has a large capacity and occupies a small space; the diesel engine uses electronic or hydraulic speed control devices, which has better speed regulation performance; the generator should use a synchronous motor equipped with brushless excitation or phase relay excitation devices, which is more reliable, has a low failure rate, and is more convenient to maintain and maintain; when the capacity of a single air conditioner or motor in the first-level load is large, a generator set with third harmonic excitation should be used; the machine is assembled on a common chassis with shock absorbers; mufflers should be installed at the outlet of the smoke exhaust pipe to reduce the impact of noise on the surrounding environment.
Choice of commonly used diesel generator sets
Some diesel generator sets are continuously carried out for a period of time or often for a long time to serve as a common power supply for electrical loads. This type of generator set is called a common generator set. Commonly used generator sets can be used as common units and backup units. In order to supply local residents' livelihood plants and domestic electricity, diesel generators need to install diesel generators, such generator sets should be carried out continuously in order to provide local residents' livelihood plants and domestic electricity.
Important facilities such as national defense engineering, communication hubs, radio stations, microwave relay stations, etc. should be equipped with backup diesel generator sets. This type of facility can be supplied by the municipal power grid at the time of use. However, after the power outage due to earthquakes, typhoons, wars and other natural disasters or man-made factors caused by damage to the municipal power grid, the installed backup units should be started quickly and insisted on long-term and uninterrupted operation to ensure continuous power supply to these important projects. This backup generator unit is also a common type of generator unit. Commonly used generator sets last for a long time and the load curve changes greatly. The unit capacity, number of units, type selection and unit control methods are different from those of emergency units.
1. Determination of capacity of commonly used diesel generator sets
The output power according to the long-term continuous operation of the unit can meet the load selection of the entire project, and the capacity of the generator set backup unit should be determined based on the importance of the load. The continuous output power of the diesel engine is generally 0.9 times the calibration power.
2. Determination of the number of commonly used diesel generator sets
The number of commonly used diesel generator sets is usually more than 2 units to ensure the continuity of power supply and adapt to changes in the applied electrical load curve. Only when there are many units, the number of units that can be determined according to the changes in the power load can be determined, so that the diesel engines are often operated under economic load to reduce fuel consumption and reduce power generation costs. The economic operating state of the diesel engine is between 75% and 90% of the calibration power. In order to ensure the continuity of power supply, the commonly used units should consider setting up backup units. When the unit fault maintenance or shutdown inspection is carried out, the generator set can still meet the continuous power supply to important power loads.
3. Determination of the speed of commonly used diesel generator sets
In order to reduce wear and increase the service life of the unit, commonly used generator sets should choose medium and low speed units with a calibrated speed not exceeding 1000r/min, and their spare units can be selected as medium and high speed units. Units of the same power station should be selected from the same model and capacity to use the same spare parts for easy maintenance and management. For projects with large load changes, units with different capacity can also be selected in the same series. The determination of the output calibration voltage of the generator is the same as that of the emergency generator set, generally 400V. In some projects with large electricity consumption and long transmission distance, high-voltage generator sets can be used.
As a professional diesel generator set manufacturer, Haixing Power has a say in the selection and purchase of diesel generator sets. There is a big difference in the selection and purchase of emergency diesel generator sets and commonly used generator sets. Let the staff talk to you about the basis for purchasing diesel generator sets in detail.
Selection of emergency diesel generators
Emergency diesel generators are mainly used in important places. Power outages instantly after an emergency or accident outage, and the emergency generator set is quickly restored and the power supply time is extended. This type of electrical load is called first-level load. Equipment, instruments and computer systems that have strict requirements on power outage time should be equipped with batteries or UPS power supply in addition to being equipped with generators.
The operation of an emergency diesel generator has two characteristics:
the first feature is for emergency use, which does not work continuously for a long time and generally only needs to operate for a few hours (≤12H);
the second feature is for backup use, the emergency generator set is usually in a state of shutdown and waiting. Only when all the main power supply is broken off, the emergency diesel generator set starts to operate to supply emergency power load. When the main power supply returns to normal, the shutdown will be switched.
(1) Determination of the generator capacity of emergency diesel generator
The calibration capacity of the emergency diesel generator set is the 12-h calibration capacity after being corrected by the atmosphere. Its capacity should be able to meet the total emergency electrical calculation load, and the calibration should be carried out according to the generator capacity that can meet the starting requirements of a single capacity motor in the first-level load. Emergency generators generally use three-phase AC synchronous generators, and their calibration output voltage is 400V
(2) When the number of emergency diesel generator sets is determined
, there is multiple generator sets for backup, generally only one emergency diesel generator set is set up. From the perspective of reliability, two units can also be selected for power supply in parallel. The number of urgently used generator sets 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, similar pressure and speed regulation characteristics, and the fuel properties used should be consistent for maintenance and shared spare parts. When there are two generator sets for emergency use, the self-starting device should enable the two units to be backup for each other, that is, after the power failure of the mains power supply is confirmed, a self-starting command will be issued. If the first unit fails to start automatically for three consecutive times, an alarm signal should be issued and the second diesel generator should be started automatically.
(3)
The emergency unit should choose high-speed, booster, low fuel consumption and the same capacity of diesel generators. The single-unit high-speed booster diesel engine has a large capacity and occupies a small space; the diesel engine uses electronic or hydraulic speed control devices, which has better speed regulation performance; the generator should use a synchronous motor equipped with brushless excitation or phase relay excitation devices, which is more reliable, has a low failure rate, and is more convenient to maintain and maintain; when the capacity of a single air conditioner or motor in the first-level load is large, a generator set with third harmonic excitation should be used; the machine is assembled on a common chassis with shock absorbers; mufflers should be installed at the outlet of the smoke exhaust pipe to reduce the impact of noise on the surrounding environment.
Selection of commonly used diesel generator sets.
Some diesel generator sets are carried out continuously for a certain period of time or often for a long time to serve as a common power supply for electrical loads. This type of generator set is called a commonly used generator set. Commonly used generator sets can be used as common units and backup units. In order to supply local residents' livelihood plants and domestic electricity, diesel generators need to install diesel generators, such generator sets should be carried out continuously in order to provide local residents' livelihood plants and domestic electricity.
Important facilities such as national defense engineering, communication hubs, radio stations, microwave relay stations, etc. should be equipped with backup diesel generator sets. This type of facility can be supplied by the municipal power grid at the time of use. However, after the power outage due to earthquakes, typhoons, wars and other natural disasters or man-made factors caused by damage to the municipal power grid, the installed backup units should be started quickly and insisted on long-term and uninterrupted operation to ensure continuous power supply to these important projects. This backup generator unit is also a common type of generator unit. Commonly used generator sets last for a long time and the load curve changes greatly. The unit capacity, number of units, type selection and unit control methods are different from those of emergency units.
1. The capacity of commonly used diesel generator sets is determined
according to the long-term continuous operation of the unit. The output power can meet the load selection of the entire project. The capacity of the generator set backup unit should be determined based on the importance of the load. The continuous output power of the diesel engine is generally 0.9 times the calibration power.
2. Determine the number of commonly used diesel generator sets.
The setting for determining the number of commonly used diesel generator sets is usually more than 2 units to ensure the continuity of power supply and adapt to changes in the applied electrical load curve. Only when there are many units, the number of units that can be determined according to the changes in the power load can be determined, so that the diesel engines are often operated under economic load to reduce fuel consumption and reduce power generation costs. The economic operating state of the diesel engine is between 75% and 90% of the calibration power. In order to ensure the continuity of power supply, the commonly used units should consider setting up backup units. When the unit fault maintenance or shutdown inspection is carried out, the generator set can still meet the continuous power supply to important power loads.
3. Determination of the speed of commonly used diesel generator sets
In order to reduce wear and increase the service life of the unit, commonly used generator sets should choose medium and low-speed units with a calibrated speed not exceeding 1000r/min, and their spare units can be selected as medium and high-speed units. Units of the same power station should be selected from the same model and capacity to use the same spare parts for easy maintenance and management. For projects with large load changes, units with different capacity can also be selected in the same series. The determination of the output calibration voltage of the generator is the same as that of the emergency generator set, generally 400V. In some projects with large electricity consumption and long transmission distance, high-voltage generator sets can be used.
