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When endurance and performance make the difference: SLIMLINE NG systems for the 450 Mhz network

BENNING power supply systems play a vital role protecting the critical infrastructure of NetCologne’s telecontrol radio network

Protecting and modernising critical infrastructure is one of the most important tasks in the upcoming years. One component is the nationwide roll-out of the 450 MHz network as a wireless communication and telecontrol platform for operators of critical infrastructures. The NetCologne teleccommunications company is also involved in the construction of this network and relies on BENNING SLIMLINE 3000 NG systems for the emergency power supply of the transmitter and repeater stations.

An ideal combination: In industrial and infrastructure applications, telecontrol typically means that processes or machines are controlled and monitored from a remote location using wide area network technologies. Such services are technically characterised by the highest demands on the devices and transmission paths used. Above all, this includes maximum security, low probability of failure and maximum availability.

This also applies to the 450 MHz radio network that is being set up throughout Germany, which therefore defines “high availability by means of emergency power supply” *1
as one of its core characteristics. This is precisely why BENNING offers individually configurable telecommunications power supplies based on the SLIMLINE 3000 NG series of rectifiers. They cover the entire bandwidth of mobile radio applications and successfully protect the entire transmission technology against network faults or failures.

SLIMLINE 3000 NG – with a few extras

In order to meet the specific requirements of NetCologne in connection with the 450 MHz radio network, BENNING supplied customised systems for 24 transmitter stations and five radio relay repeater stations last spring. The 48 V DC power supplies are configured in outdoor cabinets and equipped with lithium batteries for 72 hours of backup time. For this purpose, 32 batteries with 150 Ah each were connected in parallel. For this purpose, the batteries are equipped with a modified battery management system (BMS) and their own DC/DC converter. In this way, it is possible to keep the voltage steady, down to the lowest discharge point, and avoid excess voltage. This convincing overall concept made it possible to realise the required bridging time with 2.4 kW continuous output in a very compact outdoor system weighing just 3.5 t.

Exterior shot with closed doors of a system enclosure on a roof — The new system was installed back-to-back on the existing platform of the old power supply container. The small footprint of the new system compared to the old platform base is easy to see.

Woman with smartphone in front of a green wall

NetCologne offers products and services relating to Internet, telephone, television and mobile telephony, particularly in the greater Cologne, Bonn and Aachen areas.
With over 29,000 kilometres of laid cables and a continuous expansion, the company’s own fibre optic network is one of the most modern ones in Europe. More than half a million private and business customers make NetCologne the largest regional telecommunications provider in Germany. NetCologne has also been carbon-neutral since 2022 and was recently certified as a climate-neutral company by the independent testing service provider TÜV-Rheinland.

_{Source: www.netcologne-unternehmen.de}

Maximum energy efficiency with minimum user space

In this series of highly efficient rectifiers, the power loss that occurs when converting energy from alternating current to direct current has been reduced by up to 30 per cent compared to the previous model. At the same time, the volume of the rectifiers has been reduced by more than 33 per cent. Particularly impressive is the fact that the SLIMLINE series operates with an efficiency of up to 98 per cent in the load range from 20 to 90 per cent. With the multitude of systems that a telecommunications service provider operates in the field, this results in high savings.

Efficiency of a BENNING SLIMLINE SE and NG in relation to output power — Efficiency in relation to output power

Smooth installation on site; the outdoor cabinets are set down and installed on an existing platform using a crane.

Installation of the system technology and lithium batteries .

EU requirements fulfilled

The background: In the event of a blackout, the power supply system used must be able to provide a payload of 2.4 kW from the batteries for the base transmitter station, the radio relay technology and the fibre optic connection for a bridging period of 72 hours. In addition, the power storage unit can be fully recharged in just 26 hours, which BENNING has achieved by using three SLIMLINE rectifiers with 3000 W power each. The bridging time of three full days and fast charging are mandatory under EU Regulation 2019/941. The aim is to ensure that the energy supply companies can maintain the telecontrol processes for controlling their critical infrastructure systems even during a blackout.

Exterior shot with open doors of a system enclosure on a roof — The entire outdoor package consists of five system cabinets. The power cabinet in the picture on the far left offers generous space for the power electronics, the transmission technology and the fibre optic connection. Underneath the SLIMLINE rectifiers, also designed in 19” construction, are the basic sending station (3 U) and the switch for installation on the fibre optic network. The remaining four cabinets each hold eight 150 Ah / 48 V LiFePO batteries, providing more than enough capacity for a bridging time of 72 hours with a payload of 2.3 kW.

Impressive system benefits

In addition to their conformity with the extremely demanding EU specifications, the DC power supply systems won over NetCologne with their principle-related advantages. These included its modular design, simple redundancy and flexible scalability in case more power will be required at a later date. In addition, the modular component concept significantly reduces the time required to install or maintain the telecoms power supplies and, together with the high level of efficiency, contributes to economical operation and a low TCO (total cost of ownership). Last but not least, all modules can be hot-pluggable during operation, eliminating downtime for maintenance or servicing.

19” 1HE SLIMLINE Carrier — The 19” 1U SLIMLINE Carrier can accommodate either four 48 V and 3000 W rectifier modules combined with a SLIMLINE Controller or five rectifier modules with an output of 3000 W each.

Front view of the SLIMLINE controller — The SLIMLINE controller offers remote monitoring and operational safety in the tightest of spaces. This can be inserted into the SLIMLINE Carrier as a module for small outputs. It can also be controlled using a mobile device. This demonstrates the excellent interface design of the MCU 3000. It is intuitive, object-orientated and to the point.

Interface design of the MCU 3000 on a smartphone

The telecoms outdoor systems for NetCologne include, among other things:

A 48 V DC system with 3 SLIMLINE 3000 NG rectifiers (9 kW in total) and six spare plug-in units that allow the power to be increased to up to 27 kW
An MCU 3000 module integrated into the 19” rack for remote monitoring and control
The AC and DC distributions
Sufficient space for the customer’s technology, such as the base transmitter station (BTS), the radio relay technology (RIFU) and the fibre optic connection (GF)

Smooth processes

Thanks to the forward-looking and professional sourcing of batteries and electronic components as well as the rapid order processing, NetCologne has been able to utilise the advantages of BENNING systems since April 2023. The quick communication channels between NetCologne and BENNING also played their part. This meant that only around 14 months passed between the initial offer, the award of the contract and commissioning – including project planning and engineering with detailed adjustments to the specifications as well as various downstream optimisation processes. The co-operation with HKT GmbH, the company commissioned by NetCologne for the installation, went just as smoothly. Since commissioning and maintenance were in the hands of BENNING and will be again in the future as part of a maintenance contract, maximum availability was and is also guaranteed in this respect.

“Protecting and modernizing of the critical infrastructure are among the most important tasks of the coming years. The power supply systems used for this purpose must guarantee this reliably and ensure economical operation.”

Thomas Kerren,
BENNING Project leader