We live in a world where data has a major impact on everyday life. Visualization of data is an important mechanism since people much quicker and more easily understand visual interpretations than textual interpretations. An enormous value nowadays has real-time visualization, as it enables the representation of data flows from different sources as soon as they are available, allowing for prompt inspection and immediate response to anomalies. With the continuous development of distribution and smart electricity grids, the need for real-time observation of grid states is growing. Real-time observation of distribution systems is essential for effective management and ensuring smooth operation of networks in the future. In the diploma thesis we present the objectives of the European project SUNSEED and the theoretical background of distribution electricity grids. We focus on the development of a web application that offers efficient real-time visualization of data streams of various measuring devices within distribution electricity grids. Such an application enables distribution system operators to easily monitor individual systems. In the diploma thesis we deal with the problem of high-frequency real-time visualizations within a web-based application and propose different optimization techniques. We also present in greater detail the implementation of the final application, which contains many different components and functionalities.