Diesel Engine and Generator Power Matching and Load Calculation

We all know that diesel engines and generators are two important components of generator sets. Generally, the generator serves as the power conversion component. When we require the generator to output power to meet the load operation requirements, we usually need to first determine the generator power, then calculate and select the matching diesel engine and generator to achieve a good generator power match. Today, the editor from Dingbo Electric Generator Factory will focus on introducing the matching power and load calculation methods between generators and diesel engines.

Under normal circumstances, the diesel engine matched with the generator uses the 12-hour operation power or continuous power as the rated power (the commonly used power on the nameplate).

1.When the 12-hour operation power is selected as the rated power, it indicates that the diesel engine can continuously operate at the rated power for 12 hours, including 1 hour of continuous operation at more than 10% of the rated power.

2.When continuous power is selected as the rated power, it means the diesel engine is allowed to operate continuously for a long time, including 1 hour of operation at more than 10% of the rated power. According to national standards, the continuous power should be 90% of the 12-hour power.

The rated power indicated on the diesel engine nameplate is determined under specified standard environmental conditions. When the environmental conditions are different from the standard regulations, its power should be corrected. In matching, the diesel engine should have sufficient power to ensure that the generator outputs the rated power under rated operating conditions. When the generator outputs the rated power, the minimum output power of the diesel engine actually required can be calculated by the following formula:

Nf = (PH/n + Pe)/Ki

Where: Nf — Minimum output power of diesel engine, kW;

PH — Output power of the unit, kW;

Pe — Rated power of diesel engine under standard environmental conditions, kW;

K1 — Diesel engine power correction coefficient (when the diesel engine operates for a long time, K1 = 0.9; when the continuous working time of the diesel engine is <12h, K1 = 1);

n — Efficiency of the generator.

According to the above conversion formula, we can adjust the output power of the diesel engine to the specified range to meet the requirements of stable operation. Generally speaking, the power ratio between the generator and the diesel engine varies in different types of generator sets. For example, the ratio for commonly used fixed generator sets is 1:1.35, while for mobile generator sets, it is 1:1.6.

The load calculation formula for diesel generators is as follows:

The 2009 edition of "National Technical Measures for Civil Building Engineering Design - Electrical" provides a relatively simple formula for calculating the capacity of diesel generators:

Pe = K Kx Pn / η

Where: Pe — Rated power of the generator set, kW;

K — Reliability coefficient, taking 1.1~1.2;

Kx — Demand coefficient;

Pn — Total equipment capacity, kW;

η — Uneven coefficient of parallel units, generally taking 0.9, and 1.0 for a single unit.

It can be seen from the formula that the key to calculating the capacity of the diesel generator is to calculate the calculated capacity of the load carried by the generator, that is, the A\Pn value.

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 [email protected].