Views: 93 Author: Site Editor Publish Time: 2020-12-29 Origin: Site
Selection of emergency diesel generator
Emergency diesel generators are mainly used in important places. After an emergency or accident, the power is cut off instantly, and it is quickly recovered by the emergency generator set. The emergency diesel generator has two characteristics: first, it is used for emergency, and the continuous working time is not long, generally only needs to continue to run for a few hours (≤12H); second, it is used as a standby, and the emergency generator set is usually in a standby state. Only when all the main power supply drums are cut off, the emergency diesel generator set will start to supply emergency power load. When the main power supply returns to normal, it will immediately switch to stop.
What are the key factors in choosing emergency diesel engine generator? The details are as follows:
The nominal capacity of the emergency diesel generator set is the 12h nominal capacity after atmospheric correction. Its capacity should be able to meet the total calculated load of emergency electricity, and be verified according to the generator capacity can meet the requirements of a single large-capacity motor starting in the first-level load. Emergency generators generally use three-phase AC synchronous generators with a nominal output voltage of 400V.
When there are multiple generator sets for standby, generally only one emergency diesel generator set is set; from reliability considerations, two sets of generators can also be used in parallel for power supply. The number of generator sets for emergency use should generally not exceed 3. When multiple units are selected, the unit should try to use complete equipment with the same model, capacity, and similar pressure and speed regulation characteristics. The fuel oil used should be of the same nature for maintenance and sharing of spare parts. When there are two gensets for emergency use, the self-starting device should enable the two units to be used as spares. That is, after the power failure of the mains power supply is confirmed after a delay, the self-starting command is issued. If the starting fails, an alarm signal shall be issued and the second diesel generator shall be automatically started. For example, you can equip 3 high quality electric starting water cooled turbocharged diesel engines.
The diesel engine generator set of the emergency unit should be a diesel generator set with high speed, supercharging, low fuel consumption and the same capacity. The high-speed supercharged diesel engine has a large single-machine capacity and takes up little space; the diesel engine is equipped with an electronic speed control device, which has good speed control performance; the generator should be equipped with a brushless excitation synchronous motor, which is more reliable, has a low failure rate, and is convenient for maintenance and repair; a muffler should be installed at the exhaust pipe outlet to reduce the impact of noise on the surrounding environment.
There are several options: 6 cylinder high speed 425KW diesel engine, high speed 6 cylinder diesel engine and high speed water cooled simple diesel engine.
The control of the emergency generator set should have a fast self-starting and automatic putting device. When the main power supply fails, the emergency unit should be able to quickly start and restore power supply. The allowable power-off time for the first-level load is from ten seconds to tens of seconds, which should be determined according to the specific circumstances. When the main power supply of an important project is cut off, the determined time of 3-5S should be passed first to avoid the time of instantaneous voltage drop and the closing of the municipal power grid or the automatic input of backup power, and then the command to start the emergency generator set is issued . It takes a period of time for the command to be issued, the unit to start, and to increase the speed to full load.
Generally, large and medium-sized diesel engines also require pre-lubrication and warm-up processes, so that the oil pressure, oil temperature, and cooling water temperature during emergency loading meet the requirements of the factory's technical conditions. The pre-lubrication and warm-up process can be carried out in advance according to different situations. Emergency units such as military communications, important foreign affairs in large hotels, large-scale mass events at night in public buildings, and important surgical operations in hospitals should be in a state of pre-lubrication and warm-up, so that they can be quickly started at any time to minimize the power failure time.