In order to ensure that the non-fossil fuels account for 15% of China's energy consumption by 2020, the Chinese government has continued to release new energy policies to boost its domestic renewable energy use ratio.
Enterprise PV systems mainly supply power for their own needs and may sell excess power to the power company whereas Photovoltiac (PV) power plants specialize in solar energy collection and then feeding the energy into the grid.
To transmit the data of the PV systems, wired or wireless networks can be used. However, wireless networks have the advantage of flexibility and are the best choice for those who want quick deployment.
Located in Baoding City of Hebei Province, the Juli Group was using an enterprise PV system on the roofs of its own plants. Initially, the PV system was only installed in one plant for a small scale trail so, the company's existing wired network was to transmit data. With good power generation, the company intended to expand the use of solar cells to the whole factory which covers 2,000 square meters and includes three factories of 18 buildings. Therefore, a new PV monitoring system was required.
Taking into account the requirements of wider coverage and long distance transmission, the existing fiber-optic networks had many shortcomings such as high cost, complicated wiring, and long construction period. It was also necessary to excavate walls, drill holes, embed wires, and even destroy the original building structure. After evaluation, the Juli Group decided to adopt an easy installation and easy expansion wireless system.
Because it would be installed outside on the roofs of buildings, the wireless system had certain requirements. One of which was that they had to cope with extremes of temperatures where it can drop as low as -10C in winter and 40C in the summer. For security purposes, surveillance cameras would also be installed and having sufficient network bandwidth to transmit the PV and video data is necessary.
In order to avoid excessive bandwidth consumption when bridging Access Points (AP) and considering both deployment cost savings and system expandability, detailed network architecture planning was necessary to ensure the wireless network system would provide transmission and meet future expansion needs.
To meet these requirements, Advantech utilized two EKI products to build a Mesh backbone network with multiple wireless AP nodes. The backbone based station used the EKI-6340. Among its many functions, the three radio interfaces enable the wireless interconnection of APs throughout various plants. Providing redundancy and setting up a link in the 5.8GHz band enhanced the stability of the network operations.
By leveraging the advanced industrial mesh technology, this industrial-grade wireless AP features self-healing and self-forming capabilities allowing the wireless network to extend communication range according to various application conditions and having the failure recovery within 20ms to ensure the smooth transmission of data. Because the EKI-6340 supports 802.11n 2x2 MIMO, it guarantees transmission quality for both general and video data at a higher bandwidth with faster speed.
Also included in the network was a series of affordable and feature-rich EKI-6331AN industrial wireless APs. Through its embedded 16dBi 5.8GHZ dual-polarization (MIMO) directional antenna, it directly communicates to the backbone base station and saves the implementation costs of additional antennas and feeders. Like the aforementioned wireless EKI-6340, the EKI-6331AN also supports 802.11 2x2 MIMO giving it a three times faster data transfer rate compared to 802.11a devices. To strengthen the wireless network data security, it implements the latest encryption technologies including WPA2/WPA/802.1x to protect the data of the PV system.
Because of the severe weather, the EKI devices were chosen for their international IP waterproof and dust proof certification. In addition, Advantech uses its expertise to supply accessories from long-term partners including directional antenna, sector antenna, spiltters, and network lightning protection module to secure the outdoor wireless devices against wind and lightning while ensuring uninterrupted communication quality.