A central element of all energy generation systems and storage facilities is regulated access to the public electricity grid. This energy generation system controller (EZA) records the system data and communicates it to the grid operator. At the same time, it enables secure remote access to the system.
Burkhard Dittmann, expert for renewable energies at Phoenix Contact, explains how the control system works: “The PLCnext Control, the core of the power control unit, was trained in its control and access functions using the Matlab Simulink programming language. These functions are certified and can be used on PLCnext Controls with different performance classes.
In addition to the certified part, freely programmed functions can also be used.
In the Himmighausen solar park, the measured string current values are aggregated, i.e. the yields from the individual parts of the system. The weather sensors and the information from the data loggers are also evaluated. The power control unit therefore also acts as a weather station and data logger.”
Dittmann pats “his” control cabinet almost lovingly: “But the components alone are not enough. We had to go through a component certification process with our solution. The manufacturers of generators, such as inverters, have to obtain unit certification for their components. And then the operator still needs the system certificate. Only once the system has been certified as a complete system is the operator entitled to the full feed-in tariff. The electricity produced in Himmighausen is not only fed into the public grid, but is also sold on the electricity exchange via direct marketers.”
Phoenix Contact had the solution certified for the first time in 2019 and the process has been repeated several times since then, as functional enhancements always require recertification. In addition to the key control component, further input and output modules are required for the signal connection in accordance with the grid operator’s data point list. It is also stipulated that communication with the cabinet must be possible for up to eight hours after a mains failure. This requires an independent power supply (UVA) including batteries in the control cabinet. And if you are planning for an emergency, then you need to do it properly: the condition of these batteries is also monitored to ensure that the system works safely.
