Carbon neutrality and decarbonization are the global targets that also drive Phoenix Contact. The All Electric Society vision of the future describes a world in which energy from renewable resources is available in sufficient quantities and at affordable prices. This vision requires sustainable concepts for power supply and sector coupling, as well as intelligent energy management. One approach is to develop DC grids in industry.
Research projects such as DC-INDUSTRIE are already demonstrating the benefits of DC systems in industrial applications. The use of recuperation energy, more efficient power transmission between the sectors, and the conservation of volatile resources lead to a better energy balance in the DC grid.
As a provider of components, systems, and solutions in the field of electrical engineering, electronics, and automation, we naturally want to try out the advantages of a DC grid and the associated improved energy efficiency ourselves, and also develop innovative solutions.
It was therefore obvious for us to set up our own DC grid with our own components. We used existing solutions for the DC grid in our new Building 60 in Blomberg and developed new components that can be used in a 650 V DC grid.
The DC grid in Building 60 is supplied from the public AC grid, among other sources, and connects other generators and storage systems to the DC loads. Both renewable power generation via photovoltaic systems and the storage of energy in batteries is direct-current based. This means that there is a significant benefit through the reduction of conversion losses and material savings in the installation and devices.
The DC grid connects photovoltaic systems, battery storage systems, and e-mobility charging stations via the 650 V voltage level in a TN system. In addition, this 650 V DC grid supplies several low-voltage IT systems with 400 V. These 400 V DC subsystems are connected to loads such as lighting, control circuits, and production systems.
CHARX High Power modules are used to supply the 650 V DC grid from the low-voltage alternating-current grid (AC grid). This bidirectional connection also enables the feed-back of excess electricity from the other feed-in generators into the public supply network.
A 100 kW-peak photovoltaic system is connected to the low-voltage DC electricity distribution grid. Renewable power generation through photovoltaics is direct-current based. The CHARX power modules in a 19" format with MPP tracking make the necessary DC/DC conversion particularly easy because synchronization with an AC power grid is not required. The intelligent networking of generators and loads with an energy management system (EMS) integrates the volatile nature of power generation through photovoltaics by using a battery storage system, thus minimizing the feed-in of electricity from the public power supply grid.
A 240 kWh battery storage system is integrated to compensate for longer-lasting power requirements in Building 60. As is standard, it is located outside the building for fire protection and insurance reasons.
The battery storage system can be used to cover peak loads, known as peak shaving, when starting up large machines, for example. The battery storage system can also be used in the event of a public grid failure, thus ensuring stability and security of supply in the entire DC grid.
The bidirectional connection of e-charging stations to the 650 V DC grid enables electricity to flow in two directions. This means that vehicle batteries can be charged and used as an energy storage system at short notice. Combined with the intelligent devices from the PLCnext Control family and an EMS (energy management system), this enables very high peak loads to be covered in the short term and to contribute to the grid quality.
In a permanent installation, the 650 V DC grid supplies in-house loads. In addition, branch circuits are supplied from the 650 V DC grid via insulating converters at the 400 V DC voltage level, for example, for lighting and connections for mobile devices. The 400 V sub-DC grids are therefore isolated DC circuits (DC-IT system).
Currently, AC voltage devices in the AC low-voltage level require power supply units with internal rectification and DC intermediate circuits to supply PCs, displays, and LED lighting technology. If these devices are supplied directly from a DC grid, a large part of the weight and volume of the feed-in circuits can be saved.
Personal protection based on DIN VDE 0100-410 is taken into account with the lower voltage in the branch circuits. The IT systems are monitored for insulation and are shut down in the event of an error.
DC branch circuits with CHARX DC-DC converters can be used in high-performance industrial applications. The DIN rail power supplies of the QUINT POWER family can be used wherever a 24 V DC auxiliary supply voltage is required.
