TRANSFORMERS, SUBSTATIONS + CABLES
Omnidirectional antennas are installed on the transformer station.
The FL WLAN 5100 WLAN components can be configured as clients, repeaters, or access points.
The Bomhofsplas photovoltaic system, which floats on a gravel quarry near Zwolle in the Netherlands.
each transformer station establish connections with WLAN access points mounted in stations close to the shore. The transformer stations, which are themselves far from the shore, are coupled via repeaters to an access point to ensure consistent communication. Here, the high-level reliability and robustness of the WLAN components used was a key factor. Zebotec decided in favour of using the FL WLAN 5110 devices from Phoenix Contact. These industrial-grade devices can be configured as WLAN clients, as repeaters, or as access points. This provided Zebotec, as the system integrator, with the flexibility first to construct the control cabinets for all transformer stations to be identical, and then to configure the final WLAN network topology once installed in the respective system. Two omni-directional antennas are installed on each transformer station to exchange data between the FL WLAN 5110 devices. Due to the greater distances involved, Zebotec used directional wireless antennas to connect the access points to an FL WLAN 5110 installed at the central grid connection point on land. All the antenna cables are protected with surge protection equipment from Phoenix Contact to protect the photovoltaic system. Future projects As a system integrator Zebotec has experienced excellent performance with the managed and unmanaged switches and the WLAN components from Phoenix Contact. “This was one of the reasons we decided in favour of these infrastructure components, because the devices are ‘industrial-grade’, and therefore robust enough to satisfy our demands on high-level availability,” says Werner Neff, CEO of Zebotec. The company also plans to install the networking concepts described in future photovoltaic power stations. The same applies in respect of control technology. Zebotec has been using AXC 3050 and ILC 191 series controllers as well as bus couplers from the Inline product family for processing the diagnostics and control data within its PV systems for years. As a Phoenix Contact solution partner in the field of renewable energies, Zebotec is also one of the first companies in the world to use the new, open PLCnext Technology control platform. □
Zebotec also sets up redundant network structures, particularly in large systems and usually in the form of a ring topology via RSTP (Rapid Spanning Tree Protocol) to achieve a higher level of failsafe performance. This concept ensures data transmission between all system sections, even in the event of a connection failure in one fibreglass line. Zebotec uses FL SWITCH 2200 series Managed Switches here to ensure the required redundancy functionality. Connecting floating transformer stations to the grid Zebotec faced another challenge in a new type of PV system that presents further networking requirements. Alongside its work on large free-standing systems, the company recently started working with BayWa r.e. on photovoltaic power stations on bodies of water. Where these are not intended for tourism or for ecological management, such unused lakes are being transformed into efficient photovoltaic systems – and offer considerable advantages: they contribute, for example, to reducing CO 2 emissions, generate high yields due to the water cooling effect, and prevent conflict by providing an alternative to the need to take up land. The 27 MW floating system anchored to the lake bed of the Bomhofsplas gravel quarry close to the city of Zwolle in the Netherlands, presents a case in point. The siting of the PV system on the lake would have made cabling the transformer stations and grid connection point complex and expensive. Zebotec therefore decided on wireless Ethernet networking: the WLAN clients installed in
Werner Neff, CEO of Zebotec, recognises the durability and reliability of the Phoenix Contact components and systems.
For more information visit: www.phoenixcontact.com
MARCH 2022 Electricity + Control
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