What are the performance indicators of diesel generator sets

The technical performance index of diesel generator is the main basis for measuring the power supply quality and economic indicators of the unit. Its main technical performance usually refers to the performance that should be achieved when the power factor of the unit gradually changes or abruptly changes from the three symmetrical loads in the range of 0 100% or 100% 0 ratings.

1. Stable voltage regulation δu

where u1 is the maximum (or minimum) value of the temperature power supply after the load change; u - no-load setting voltage value.

The δu of the class unit is (1 3)%; The δu of the class unit does not exceed 5%.

2. Steady-state frequency regulation δf

where f1 is the maximum (or minimum) value of the steady-state frequency after the load gradient;

f2 - frequency at rated load;

f – Rated frequency.

The δf of the class unit is; The δF of the class unit does not exceed 5%.

3. Voltage stabilization time.

When a load changes abruptly, the time it takes for the voltage to begin to stabilize is calculated and is usually measured with an oscilloscope.

The voltage stability time of the class unit is; The voltage stability time of the class unit is 3s.

Fourth, the frequency stability time.

The time required from the time of sudden change in load to the time when the frequency begins to stabilize is usually measured with an oscilloscope.

The frequency stability time of class units is 2 5s; The frequency stability time of the class unit is 7s.

5. No-load voltage setting range.

The setting voltage of the unit should be able to adjust and work stably within the range of 95% to 105% of the rated value. For example, the no-load voltage of a unit with a rated voltage of 400V can be adjusted between 380 and 420V.

6. The stability of the operating voltage under the three-phase asymmetric load.

When the power supply of the unit is running under the three-phase asymmetric load, if the current of each phase does not exceed the rated value, and the difference of the current of each phase does not exceed 25% of the rated value, the difference between the voltage of each line and the average value of the three-phase voltage shall not exceed 5% of the average value of the three-phase line voltage.

7. Parallel performance of the unit.

Two three-camera units with the same specifications and models should be able to operate stably in parallel within the range of 20% to 100% of the rated power under the rated power factor. In order to improve the active power and reactive power, reasonable distribution accuracy and operation stability, the diesel engine governor in the unit is required to have a device that adjusts within the range of 2% and 5% of the steady-state regulation rate. The voltage regulating device in the control box (screen) can adjust the steady-state voltage regulation within the range of 5%.

The problem ratio is more ambiguous. Preliminary talk: different projects, different capacities, must choose different power generators.

The purpose of your generator is to carry the load, first of all, according to the load size to determine, and secondly, if the load is mostly a motor, the starting current should be considered, and the hard starting current is several times the side power to be multiplied by the corresponding multiple. In addition, if the load is mostly non-linear load, the usual way is to choose a permanent magnet exciter (PMG) generator set. Example load for 50kw motor generator selection:

Generally, the one-time loading capacity of the generator set is not convenient to exceed 60%. Excessive sudden load can cause excessive torque shocks on the generator and engine, as well as excessive voltage fluctuations on the electric ball.

When the motor starts directly, the current is about 7 times, and the generator set must first meet the power of 7 * motor.

It is best to choose a generator set of about 350kw.

The calculation method for other startup methods is the same as above (only the startup multiple can be changed).

The automatic switching cabinet is also called the double power supply cabinet, which plays a bridge role between the diesel generator set power, the mains power and the load. The automatic switching cabinet can ensure that when the mains power supply fails, the generator set will complete the power supply conversion within the set time (3s 10s) after automatic start, so as to realize the power supply to the load, and automatically switch to the mains power supply when the mains power is restored.

The performance of diesel generator sets generally needs to meet the requirements of GB T2820, which generally includes:

With the continuous improvement of the quality and performance of domestic diesel generator sets, generator sets are widely used in hospitals, guesthouses, hotels, real estate and other industries. The performance level of diesel generators is divided into G1, G2, G3 and G4.

Class G1: This class requirement applies to connected loads whose basic parameters only require specifying their voltage and frequency. Examples: General purpose (lighting and other simple electrical loads).

Class G2: This class requirement applies to loads that have the same voltage characteristics as the utility power system. When the load changes, there can be a temporary but permissible deviation in voltage and frequency. Examples: Lighting systems; Pumps, fans and winches.

Class G3: This level requirement is applicable to connected devices that have strict requirements for the stability and grade of frequency, voltage, and waveform characteristics. Example:

Radio communication and silicon steer rectifier controlled loads. It should be particularly recognized that special considerations are required regarding the influence of the load on the voltage waveform of the generator set.

Class G4: This class is required for loads that have particularly stringent requirements for frequency, voltage, and waveform characteristics. Example: Data processing equipment or computer system.

National Standard GB T2820Article 7 of the 1-1997 "Reciprocating Internal Combustion Engine Driven Alternator Sets" Part I: Use, Quota and Performance stipulates four levels of performance for diesel generator sets.

1) The G1 performance requirements apply to connected loads that only need to specify the basic parameters of their voltage and frequency. Mainly for general use such as lighting and other simple electrical loads.

2) The G2 performance requirements are applicable to loads that have the same voltage characteristics as the utility power system. When its load changes, there can be a temporary, however permissible deviation in voltage and frequency. Such as lighting systems, pumps and fans.

3) G3 performance requirements are applicable to connected devices with strict requirements for frequency, voltage and waveform characteristics. such as radio communications and thyristor rectifier controlled loads.

4) G4 performance requirements are for loads with particularly stringent requirements for frequency, voltage, and waveform characteristics. Such as data processing equipment or grate counting systems.

According to the national standard GB alternator sets driven by reciprocating internal combustion engines Part 1; Article 7 in Uses, Quotas and Performance stipulates four levels of performance for diesel generator sets.

1. G1 performance; The requirements apply to connected loads whose basic voltage and frequency parameters only need to be specified. Mainly for general use such as lighting and other simple electrical loads.

2. G2 performance; The requirements apply to loads that have the same voltage characteristics as utility power. When its load changes, there are temporary, however permissible voltage and frequency deviations. Such as lighting systems, fans and pumps.

3. G3 level performance, which is required to be suitable for load connection equipment with strict requirements for frequency, voltage and waveform characteristics. Such as telecom loads and thyristor-controlled loads.

4. G4 performance, which is required to be suitable for loads with strict requirements for frequency, voltage and waveform characteristics. Such as data processing equipment or computer systems.

Unit performance indicators include:

1. Voltage setting range.

It refers to the range of adjusting the voltage setting device to two limit positions, that is, the maximum value and the minimum value, when the generator set is no-load at the rated speed. The no-load voltage setting range is specified as 95% to 105% of the rated voltage.

2. Steady-state voltage regulation.

Refers to the rate of change of steady-state voltage under all loads from no-load to rated load, expressed by δu. It reflects the constant voltage accuracy of the generator. The steady-state voltage regulation of the alternator set should not exceed ;

3. Transient voltage regulation.

It refers to the instantaneous voltage change rate in the whole process of the generator set when the generator set is no-load, the speed and voltage are rated value, the specified load is suddenly added, and then the load is suddenly thrown off.

4. Voltage stabilization time.

Refers to the time it takes for the voltage to change from a sudden change in load to the range of 1 ± 3% of the voltage to a stable voltage.

5. Steady-state frequency regulation.

Refers to the ratio of the difference between the stable frequency of the generator set and the rated frequency before and after the load change, expressed as a percentage.

6. Transient frequency regulation.

Refers to the ratio of the difference between the instantaneous frequency and the frequency before the load change and the fixed frequency when the load of the generator set is abruptly changed, expressed as a percentage.

7. Voltage fluctuation.

Refers to the degree to which the voltage fluctuation of the generator set under constant load is expressed as a percentage.

8. Frequency volatility.

Refers to the degree to which the frequency of the generator set fluctuates when the load is constant, expressed as a percentage.

9. Sinusoidal distortion rate of line voltage waveform. Refers to the percentage of the root mean square value of the sum of the square of each harmonic voltage other than the fundamental voltage to the fundamental voltage ratio, expressed as ku. The voltage waveform distortion rate is small, which means that the output voltage is ***.

10. Temperature rise.

Refers to the temperature increase value of each winding when the generator runs to thermal stability under rated working conditions, which is expressed by . The temperature rise is too high. This means that the service life of the generator will be shortened.

11. Voltage deviation during three-phase asymmetric load. Refers to the percentage of the ratio of the difference between the maximum value (or minimum value) of the three-phase voltage and the average value of the three-phase voltage and the average value of the three-phase voltage when the difference between the two-phase current in the three-phase asymmetrical load borne by the generator set does not exceed 25% of the rated current, and the maximum one-phase current does not exceed the rated value. Denoted by af.

12. Voltage changes in hot and cold states.

Refers to the rate of voltage change of the generator set from cold to hot under rated working conditions. with δu;Denote. The low rate of change means good voltage stability from cold to hot.

13. Noise.

Refers to the sound pressure level measured at lm distance from the generator set. The noise of the generator set is assessed according to the sound power level of a count. High noise means that there is a lot of pollution to the environment.

14 vibrations. Refers to the vibration amplitude of the generator set, and the generator set is assessed according to the effective value of vibration speed. The vibration is large, the power generation unit can not operate normally, and the service life of the generator set is also shortened.

Diesel generator sets have four levels of performance:

A. The G1 performance requirements are applicable to connected loads that only need to specify the basic parameters of their voltage and frequency. Mainly for general use such as lighting and other simple electrical loads.

B. G2 performance requirements are applicable to loads that have the same voltage characteristics as the utility power system. When its load changes, there can be a temporary but permissible voltage and frequency deviation. Such as lighting systems, pumps and fans.

C. G3 performance requirements are suitable for connection equipment with strict requirements for frequency, voltage and waveform characteristics. such as radio communications and thyristor rectifier controlled loads.

D. G4 performance requirements are suitable for loads with particularly strict requirements for frequency, voltage and waveform characteristics. Such as data processing equipment or fraud grate systems.

5. Many consumers think that the quality of domestic machines is not very good, but in fact, it is not. The quality of the domestic diesel engine has been very hard, and the key is whether it is the original and authentic goods that are bought. If you buy a fake, the quality is really very poor.

The counterfeit situation of imported diesel generator sets is also very serious, and the quality is also very bad.