What is a diesel power generator, and how does it work?

Diesel power generators

Electricity is present in the lives of the vast majority of people. We use it for many things, as much at home as at work. Through its conversion, we can obtain other forms of useful energy such as light, heat, mechanical or kinetic energy, without which daily activities or communication would be virtually impossible. The public sector, health care, shopping malls and banks, and business entities, including industrial plants or factories also depend on the supply of electricity and can suffer all sorts of losses caused by its absence, which they cannot afford.

The electricity distribution system is exposed to many dangers that cause power shortages daily. The role of protection for this type of situation is played by a diesel generator. It is a set of equipment that forms a unit that can supply the necessary amounts of missing electricity in a short time.

In the event of a grid power outage, we can quickly (within seconds) prevent it or restore electricity. In such a case, a diesel power generator in the electrical system may be helpful, as it acts as a so-called emergency power source ensuring emergency operation both in homes and the above-mentioned entities.

Diesel generators are also used in places where there is no connection to the power grid, such as construction sites or outdoor events where they act as a constant source of power, so-called generators for continuous operation.

CAT C32 diesel power generator

Operating principle

A diesel generator is a device that produces electricity by burning diesel fuel. Combustion occurs in a diesel engine where the heat generated in its process, due to the increased pressure, sets the pistons in motion. Thus, it generates kinetic energy for the rotary motion that drives the shaft. The shaft through the clutch transfers mechanical energy to the alternator, where electrical energy is generated with the phenomenon of electromagnetic induction.

Generator build

The diesel power generator is built of two main components: an engine and an electric generator. The basic equipment also includes a frame-mounted cooler, an electronic control panel, a main switch and electrical contacts or connection sockets. All the elements are mounted on a steel frame. Depending on the power, there is a fuel tank in the frame of the unit. The generator can be placed in a factory housing, containerised housing or can be installed in a specially adapted room.

Breakdown

The available generator units are divided according to:

1. Type (time) of work:

• Standby operation – backup power used in the event of a failure of the main power supply. Variable load. No overload is possible.
• Prime operation – continuous power supply. Variable load. Unlimited operation time. Overload possible by 10% for 1 hour per every 12 hours of operation.

2. Mounting:

• Stationary generator – permanently plugged into the facility’s grid, often equipped with an automatic switching system, known as the АTS. Placed either outside or inside the facility.
• Mobile generator – in a housing, mounted on an approved chassis designed specifically for power generators.

3. Power – depending on needs, from 9.5 to 4000kVA in a single block.

Operation

The operating costs of a power generator depend on the chosen unit and its purpose. The amount of fuel burned depends on the power of the generator, the type of operation (standby/prime) and the load. Similarly, inspection costs depend on the power of the generator unit, which translates into the size (capacity) of the engine, and thus the amount of fluids and consumable parts.

The table below shows the combustion of two generators with different power and engine capacities for a given load.

Diesel combustion table for 250 kVA and 1100 kVA generators:

We can see how the amount of fuel burned changes concerning the aforementioned variables. Thus, for a 250 kVA unit operating 2 hours a month at 75% load (emergency operation), fuel costs will be PLN 213.59 at PLN 5.30/litre of diesel fuel.

Therefore, before deciding to purchase a generator, it is necessary to consider some issues and agree on where and how it will be used.

Undoubtedly, diesel generators are indispensable for the proper functioning of many sectors of the economy so it is worth keeping them in mind when planning investments.

asusol@eneria.pl

Written by: Arkadiusz Susoł

Sales Engineer in Power Generatorsets Department