Real-time Voltage Monitoring Using Solar PV Inverters in Distribution Grids.

Abstract

The increasing penetration of solar PV inverters into distribution grids has led to voltage quality issues, particularly over-voltage concerns. Currently, there is no real-time voltage monitoring system in place in Sri Lanka. This work proposes a system for grid operators to monitor voltage at points where solar PV systems are connected. The propsed system extracts real-time voltage data from multiple inverters, which are connected to the internet. The key PQ parameters extracted from the inverters include voltage, current, power factor, and active/reactive power. To retrieve real-time data, the inverter must be connected to the internet. For such internet-enabled inverters, data is accessed through API. In this method, inverter manufacturer's API is accessed through a central server using standard internet protocols. Since each manufacturer provides a unique API, connections must be tailored to the respective brand. User credentials and API access keys authenticate the data retrieval process, ensuring seamless and secure data transmission to the server. Currently, each inverter manufacturer provides its own dedicated platform that supports integration only for inverters of the same brand. This approach is impractical for grid operators, as the presence of numerous inverter brands requires them to log into multiple systems separately - a process that is cumbersome and inefficient. Additionally, grid operators currently lack access to these platforms, which are typically restricted to PV system installers and customers. In the proposed system the extracted data from multiple inverters will be visulized on a map. With this solution, grid operators can monitor real-time voltage levels at any location where inverters are installed. Also historical data from the inverters can be downloaded for further analysis on the over-voltage issues in the grids with PV systems. This will enable operators to efficiently track over-voltage issues and supports decision-making, such as approving new PV connections and proposing solutions to over-voltage problems.