Limitations on The Output Power of Diesel Generators

Diesel generators are often used as power equipment in hiking areas or outdoor work. Before purchasing a diesel generator, it is the preferred power equipment for sudden power outages or backup power sources. To achieve optimal power supply performance, a clear understanding of the kilowatt level is necessary, and the difference between kilovolt ampere (kVA) and power factor (PF) is very important.

Kilowatts (kW) are used to measure the actual electricity provided by generators and are directly used inside buildings.

Measure apparent power in kilovolt amperes (kVA). This includes active power (kW) and reactive power (kVAR) consumed by equipment such as motors and transformers. No power is used for consumption, but rather for cycling between power and load.

The power factor is the ratio of active power to apparent power. When using 900kW and 1000kVA, the power factor is 0.90-90%.

The I-beam of diesel generator is rated in kW, kVA, and PF. To ensure that you can choose the most suitable diesel generator set for yourself, it is recommended to have a professional electrical engineer determine the size of the set.

The maximum output power of the generator set is driven by a diesel generator. For example, consider a generator driven by a 1000 horsepower diesel engine with a 95% efficiency:

1000 horsepower is equivalent to 745.7 kilowatts, which is the shaft power of the generator.

The work efficiency reaches 95%, and the maximum output power is 708.4kW.

The maximum KVA depends on the voltage and current of the generator. There are two ways for the unit to overload:

If the load connected to the generator exceeds the rated power, it will cause the engine to overload.

On the contrary, if the load exceeds the rated kVA, it will overload the winding of the generator.

Therefore, it must be remembered that even if the kilowatt power of the load is lower than the rated value, the generator may overload to kilovolts.

If the building consumes 1000kW and 1100kVA of electricity, the power factor can be increased to 91%, but not exceeding the power generation capacity.

In addition, when the generator operates at 1100kW and 1250kVA, the power factor can only be increased to 88%, and the diesel generator is overloaded.

Diesel generators can also be overloaded in kVA units. If the equipment is running, even if the diesel engine is not overloaded, there are still 950kW and 1300kVA (73% PF), and the winding is still overloaded.

In short, as long as the rated power of diesel generators is maintained below their rated values, there will be no problems. The recommended power should not be lower than the rated PF, as the generator efficiency is low. Ultimately, exceeding the rated value of kW or kVA will damage the equipment.

The impact of early power factor and hysteresis on the performance of diesel generators.

If only the resistor is connected to the resistor and the voltage and current are measured, the AC waveform matches the digital meter. The positive and negative signs can cross both 0V and 0A signals interchangeably. In other words, voltage and current are in phase.

In this example, the power factor of the load is 1.0 or 100%. But the power factor of most devices is not 100%, which means that their voltage and current will deviate from each other:

When the peak AC voltage exceeds the peak current, the power factor of the load will lag. A load with this characteristic is called an inductive load, which includes a motor and a transformer.

On the contrary, if the current exceeds the voltage, the load will generate a leading power factor. A load with this characteristic is called a capacitive load, which includes batteries, capacitors, and certain electronic devices.

Most buildings have a greater load than the allowable load. That is to say, the total power factor is generally lagging, and diesel generator sets are specifically designed for this load. However, if there is a significant allowable load in the building, the owner must be cautious because the voltage of the generator will change before the power factor. This will trigger automatic protection, separating the equipment from the building.

As a professional diesel generator manufacturer, we always insist on using first-class talents to build a first-class enterprise, create first-class products, create first-class services, and strive to build a first-class domestic enterprise. If you would like to get more information welcome to contact us via sales@dieselgeneratortech.com.