Selection of emergency diesel generator

Emergency diesel generator is mainly used in important places, in case of emergency or after the accident power outages instantaneous power outages, through the emergency generator set to quickly restore and extend a period of power supply time. This type of electrical load is called a primary load. Equipment, meters and computer systems that have strict requirements for power down time shall be supplied with batteries or UPS power, in addition to generators.

Emergency diesel generator work has two characteristics:

The first characteristic is for emergency, continuous working time is not long, generally only need a few hours of continuous operation (less than 12H);

The second characteristic is the reserve of emergency generator in a normal shutdown wait state, only when the main power supply for all the drum barrier after power failure, the emergency diesel generator starting operation to supply emergency power load, when the main power switch immediately after normal shutdown.

(1) determination of generator capacity of emergency diesel generator;

The calibration of the capacity of emergency diesel generator set for the atmospheric correction after the calibration of 12h capacity, the capacity should be able to meet the emergency load power calculation, and can meet the requirements of the single largest capacity motor starting a load checked by the generator capacity. The emergency generator usually uses three-phase AC synchronous generator whose output voltage is 400V

(2) determination of the number of emergency diesel generator sets;

When there are more than one generator set, only 1 emergency diesel generator sets are installed. From the reliability consideration, 2 units can be used in parallel to supply power. The power supply emergency units in general should not be more than 3 taiwan. When using multiple units, the units should try to choose the same type, capacity, speed regulation and similar characteristics of the complete sets of equipment, the fuel used should be consistent in order to repair, maintenance and sharing of spare parts. When the supply of emergency generator 2, self starter should make 2 units to spare to each other, i.e. power failure after the delay confirmation, a self starting instruction, if the first units for 3 times since the start of failure, should send the alarm signal and automatically starting second diesel generators.

(3) the selection of emergency diesel generator;

Emergency units should be equipped with high speed, low pressure, low fuel consumption and the same capacity of diesel generator sets. The capacity of single machine high speed turbocharged diesel engine is large, small occupying space; selection of diesel engine with electronic or hydraulic control device, good control performance; synchronous motor with brushless excitation generator should be selected or the phase compound excitation device, more reliable, low failure rate, convenient maintenance and overhaul; when a load of a single air conditioner the capacity or the motor capacity is larger, should choose the three harmonic excitation generator; machine assembled in common with the shock absorber on the chassis; the exhaust pipe outlet should be installed muffler, to reduce the noise influence on the surrounding environment.

(4) control of emergency diesel generator set;

The control of emergency generator set should have quick self starting and automatic input device. When the main power failure power failure, the emergency unit should be able to quickly self starting and restore power supply, the first load of the allowable outage time from ten seconds to dozens of seconds, should be determined in accordance with specific circumstances. When the main power supply for important engineering power, should be based on 3-5S to determine the time, automatic input to reduce the instantaneous voltage and avoid power switching or standby power supply time, and then start the emergency generator instruction. It takes a period of time from the instruction, the start of the unit and the speed of the lift to full load. Generally large and medium-sized diesel engine need pre lubrication and warm process, shall make the oil oil pressure, oil temperature, loading of the emergency cooling water temperature to meet the technical conditions of products; pre lubrication and warm process can be carried out in advance according to different situations. For example, military communication, large-scale hotel important foreign affairs activities, public buildings, large-scale mass activities at night hospital for emergency surgery important unit usually should be in the pre lubrication and warm state, in order to keep a fast start, try to shorten the fault outage time.

After the emergency unit is put into operation, in order to reduce the mechanical and current impact on the sudden load, the emergency load should be increased at intervals according to the demand of power supply. According to the national standard and national military standard, after the success of the first allowed loading are as follows: automatic unit self starting for the calibration of power is less than 250KW, for the first time to allow loading of not less than 50% for the calibration of calibration load; power is greater than 250KW, according to the provisions of a technology factory. If the instantaneous voltage drop and the transition process are not strict, the load of sudden increase or sudden discharge of the unit should not exceed 70% of the unit calibration capacity.