AC service entrance and panels for DC power systems

For the development of any electrical project, it is necessary to follow certain guidelines to ensure technical efficiency and safety. This is crucial, especially in the case of the service entrance and AC distribution panels for DC electrical power systems.

Here are the most important design criteria for supplying AC power in DC electrical systems. Let’s get started!

AC electrical service entrance

The design of AC electrical systems for any area is essentially a matter of foresight and arrangements of conductors and equipment. Its primary goal is to safely and effectively transport electrical energy from the power source to the energy-consuming elements.

To size and select the AC service entrance for any DC system, the following is necessary:

• Load study, where you must take into account that the usage time of each equipment will be 24 hours. It is also necessary to use the maximum consumption value indicated on the equipment’s nameplate.
• Voltage level of the locality

On the other hand, for a power system intended to serve a critical installation, a redundant service entrance must be established. By this, we mean that the building should have at least a double service entrance.

Each one should come from an independent power source, which can be two independent substations.

It is a current trend to connect one of them to a conventional electrical substation. The other, which would only feed the DC power system, should come from a exclusively dedicated photovoltaic system

AC distribution boards for DC systems

To calculate, size, and select the electrical distribution boards for any critical DC installation, it is necessary to determine the following:

• Permissible short-circuit level, including maximum time. This is for sizing the copper bars
• Feeder calculation, which determines the maximum consumption of the board
• Current capacity of the switches to be used, for which the previously mentioned load study is important.

Division of AC distribution boards

It is worth noting that it is a good practice for buildings in general to divide distribution boards by service.

This way, it will be much easier to isolate a possible electrical failure and affect the installation in general as little as possible. This is especially important for the most important circuits.

The first separation is established between those boards that are backed up by the generator set and those that are not. The former are called “emergency service” and the latter “normal service”.

Here are the circuits that typically feed:

• Normal service panels, office equipment and areas, lighting, non-prioritized water pumps and elevators, among others.
• Emergency service panels, DC power systems, emergency systems such as fire and evacuation, production, just to name a few.

Specifically, the electrical service panels for critical equipment, which are the emergency ones, are divided as follows:

• DC system electrical panel, such as rectifiers and UPS
• Electrical panel for air conditioning in technical areas
• Electrical panel for lighting and prioritized outlets in technical workroom
• Server electrical panel

That concludes the design criteria for AC service and panels

As you can see, the sizing of AC electricity for a DC system is much more demanding than for other uses. This is true for both the AC service and the AC distribution panels.

If you want more information on this topic, we invite you to read our posts Electricity: only what you need to know and Electricity in telecommunications.

Also, don’t forget to purchase the Dimensioning and design of dc power systems for telecommunications and critical systems course. With this course, you will learn everything you need to become an expert. You can see its content here.

Also, at energydcac, you will find a lot of content on this topic and on AC/DC energy in general. Visit us and see for yourself!