Always on! – The transmission network of the Norddeutscher Rundfunk (NDR; Northern German Broadcasting)
NDR continues to rely on UPS systems and the engineering of its partners rd Notstromtechnik and BENNING for the modernisation of the power supplies at its transmitter sites
One of the core missions of the public service media is to provide diverse and objective coverage that supports viewers in forming their own opinions freely and independently. Continuous, area-wide reception of radio and TV is ensured by widely distributed, earth-bound transmitter stations with basic network and filler transmitters. In case of a transmitter failure, it would no longer be possible to receive films and reports or even news and current warnings in the affected region.
With that in mind, continuous availability of the operated transmitter systems around the clock is crucial. Downtimes are not acceptable. Therefore, the installations, controls and monitoring systems used here must be consistently protected against the failure or disturbances of the power supply network.
Tried and tested for decades
Norddeutscher Rundfunk (NDR) has been using BENNING power supplies for transmitter technology for decades. Between 2004 and 2007, BENNING supplied fused, uninterruptible DC/AC power supply systems (60 V DC/230 V AC) to supply power to the transmitter systems, as well as modular 24 V power supplies responsible for starting the diesel engines in the emergency power systems.
These power supply systems already had monitoring and remote maintenance capabilities that enabled the service technicians, who were usually responsible for multiple sites, to be efficient and proactive in their maintenance processes. In northern Germany, NDR has further optimised the transmitter network in some regions, and additional transmitter sites have been added. Furthermore, the ageing power supplies at the transmitter sites are gradually being replaced with modern power supply systems of equal capacity.
This is intended to guarantee a fail-safe but also sustainably economical operation of the transmitters for the future.
Launch at the Hanover Trade Fair 2016
The early planning for this project dates back to 2016. NDR employees visited BENNING during the Hanover Fair. At this time, the new modular rectifier series TEBECHOP SE was announced and the first prototypes were presented.
In the joint discussions, the idea arose to replace the old rectifier systems with these highly efficient, high-performance modules.
In combination with the modular 19” inverter systems INVERTRONIC compact (which were also new at this time), a very flexible and economic platform was created. Its purpose was to provide complete battery-supported backup power supplies with the highest availability, which reliably supply critical consumers with good quality electrical energy. At the same time, spare parts availability and proactive maintenance options are ensured.
“We see the renewed order award as confirmation of this partnership-based cooperation and of NDR’s confidence in the reliability of our power supply systems.”
BENNING Project leader
Due to the positive experience with the previous modular BENNING UPS systems, rd Notstromtechnik and BENNING were to jointly prepare a corresponding offer. Flexibly responding to the special wishes of the customer, the project team developed the best possible solution together with NDR. “We see the renewed contract as a confirmation of the previous cooperation based on partnership and the trust of NDR in the reliability of our power supply systems,” says Paul-Gerd Demming, responsible project manager at BENNING.
The company rd Notstromtechnik, as NDR’s contractor, is responsible for the replacement, installation, commissioning and instruction of the new power supplies. The detailed training of the NDR service technicians takes place at the BENNING training centre in Bocholt, North Rhine-Westphalia.
In the spirit of sustainability and safety, spare parts for the sites that have not yet been converted are obtained from the old plants.
For instance, the rectifier and inverter modules, the electronic switching equipment and the remote monitoring unit are carefully removed and handed over to NDR for storage.
Coating for a secure seal
In the newly installed power supply systems, five 19” TEBECHOP SE rectifier modules (58 V/40 A) take over the uninterruptible supply of the critical 60 V consumers, which include the telecontrol system, the emergency lighting and the transmission technology in the signal transfer rooms. In order to keep the overall system as compact as possible, the 60 V system also simultaneously feeds the five inverters of the INVERTRONIC compact type (2500 VA/2000 W). The latter guarantee, among other things, the power supply of the transmitter control stages with 230 V alternating current.
The boards of all 19” modules are sealed with a special coating. This way, BENNING takes into account the special environmental conditions of the various installation locations, for example condensation due to temperature fluctuations or corrosion due to the salty sea air in the coastal region of northern Germany.
The block diagram shows the principle of the modular architecture of a power supply system with modular rectifiers, inverters and DC converters
Sustainable system architecture
Due to the modular system architecture, there is no need to over-dimension the power supply system at the time of installation.
Instead, there is a redundant design in n+1 technology and additional reserve spaces are provided, which can simply be equipped with the corresponding number of power modules if an increase in power is required at a later date.The transmitter station is thus ideally equipped for the challenges of today and the opportunities of tomorrow.
Although the maximum availability of the UPS system is in the foreground, it operates highly energy-efficiently due to its topology. This is because the active power modules are utilised in such a way that they operate within their optimum efficiency.
In addition to the rectifiers and inverters, the electronic switching device is also designed as a hot-swappable module. This means that the most important components can be serviced or replaced by service personnel in less than 10 minutes without affecting the connected consumers.
Smart monitoring with MCU 3000
In general, continuous and economical operation of power supply systems requires that they can be analysed and maintained with the help of powerful control and monitoring systems. Here, this is done by the Monitoring and Control Unit 3000 (MCU 3000). The unit built into the front door monitors the entire power supply system and controls the power management, among other things. Individually adjustable, automatable or event-controlled processes significantly reduce the time required for installation, monitoring and maintenance.
Preventive maintenance or service processes are triggered in good time on the basis of freely definable limit values and tolerances even before major damage occurs.
The 10.4-inch touch display not only simplifies operation, but also contributes to a clear display of the current energy flow in the UPS system. A large LED strip integrated into the carrier frame of the MCU clearly signals the system status. To enable messages and operating values to be read out remotely via the MCU’s web-based interface, a network connection is provided by means of a surge-protected RJ45 connector. Data transmission is secured using SSL encryption and the service technicians responsible for the respective location can use either a PC or a mobile device for secure access.
Hanover transmitter project completed
With the proper commissioning of the new power supply system at the Hanover broadcasting site, another UPS system was handed over to NDR on 24 January 2023. The conversion of the NDR transmitter sites is progressing steadily and will thus ensure that NDR can continue to broadcast its diverse radio and television programmes nationwide and without interruption.