Renovation of old power stations

    A few days ago, the renovation project of 37 combiner boxes in Jiaxing, which was in charge of Fonrich New Energy, was successfully completed. The renovation plan designed and installed by Fonrich and its high-quality products and services were highly recognized by the owners.

Site survey in the early stage of the project

    Fonrich engineers have carried out a detailed and thorough preliminary investigation of the renovation project. The number of combiner boxes on the roof of this project is small but scattered. If the traditional wired communication method is used, the following problems may occur: 1. It affects the aesthetics of the building; 2. . Due to site factors, a large amount of 485 lines are required to affect the economic benefits of the project; 3. The communication distance between the roof and the roof of this project is short, and most of the blocking factors are the height difference between the roofs, which may lead to irregular wiring and affect communication quality.

    Based on the above factors, the engineer recommended the wireless communication solution to the customer. The reconstruction project of 37 combiner boxes this time is distributed in three areas. We select one area (15 units) for a detailed introduction, so that everyone can understand the detailed process and related details of the old power station reconstruction.

Specific renovation details

For the wireless communication engineering application case, in the selection of the antenna bracket, the engineer comprehensively considered several aspects such as corrosion resistance, high temperature resistance, and ease of use, and selected PVC pipe (diameter 2.0cm, length 75cm) as the antenna bracket, as shown in the figure below.

Antenna bracket

There are two installation methods:

1. It is installed between the two panels, with a immersion distance of 60cm and an extension distance of 15cm (it has been analyzed by PVsyst software, and the impact on the system can be ignored).

2. Set it on the lightning protection iron rod on the roof (because there are more than a dozen lightning protection iron rods on the roof, only one is occupied, so the impact can be ignored).

Regarding lightning protection considerations, based on the annual average number of thunderstorm days in Jiaxing City is 40 days, the on-site thunderstorms are divided into direct lightning and indirect lightning. Indirect lightning is not considered for the insulation of PVC pipes. The coefficient is above P90.

Because the wireless solution is selected, the gateway needs to be installed to receive the monitoring data of the combiner box. The gateway communicates with the communication management machine through RS485 wired communication, and the communication management machine is in the inverter room, so the gateway is placed on the roof of the inverter room. The site distribution is shown in the figure below:

Satellite map of distribution of combiner boxes and gateways

Among them, the MW1 combiner box monitoring is the farthest away from the gateway, the straight-line distance is 161 meters, there are 2 roofs shielding, and the height drop is about 10 meters. The MW11 combiner box monitoring is the closest to the gateway, with a straight-line distance of 36 meters without obvious obstruction.

The on-site renovation situation is shown in the following group of legends:

Comparison diagram of combiner box before and after transformation

Wireless communication antenna placement diagram

For the placement of the gateway, considering that the gateway needs to communicate with the inverter via 485, and then the inverter sends the collected data of the gateway to the data backend wirelessly, the gateway can only be placed in the room where the inverter is located. On the roof, electricity is drawn through the AC 220V in the inverter room.

Gateway Antenna Placement Diagram

Communication test results: The host computer test, the monitoring data of 15 combiner boxes are all read correctly.

So far, the combiner box renovation project of this power station has come to an end perfectly. Fonrich staff have demonstrated their strong professional qualities from the preliminary field investigation, to the scheme design, and then to the subsequent installation. They use scientific methods and superb technology to make the old power station work. Towards refined data management.