Alternative solutions, instead of building new transmission lines, are needed to enable the fast electrification of sectors such as industry, transportation, and heating. This includes smart-grid technology allowing for an increase in hosting capacity without the need for building new transmission lines. The increase in hosting capacity beyond the firm hosting capacity is, with many of the schemes, related to the ability of the installation to tolerate curtailment. The paper gives an overview of different smart-grid schemes and how they potentially increase the hosting capacity. The connection of a large electrolyser installation for hydrogen production is used as an illustrative example introducing some of the issues.

The deterministic techniques in use for transmission-grid planning and operation have resulted in a high reliability, but they have certain limitations that could be removed by applying stochastic techniques. This paper presents a detailed review of one such stochastic technique: operational risk assessment. A general procedural model of operational risk assessment is introduced, based on one simple equation, highlighting the important elements. The research trends are presented for each of these elements: contingency definition and calculating the probability of a contingency case; contingency filtration methods; defining and calculating the severity factor. Next to an overview of the state-of-the-art, this paper contains a detailed discussion section, where the most important research gaps are identified. Emphasis is especially on bridging the gap between research and practical applications of operational risk assessment. The paper closes with a future outlook on operational risk assessment and its applications.

The increased complexity of the transmission grid can endanger the operational security of the grid. Operational risk assessment, a stochastic tool, helps to enhance security. Contingency analysis and its impact quantification are the main constituents of operational risk assessment. In this study, different graphical methods are proposed to visualize operational risk contingency-based detailed results: heat-map and risk-based contingency chart. Through the heat-map, the system operator can determine which contingencies contribute most to the operational risk and would therefore be the most threatening contingencies for operational security of the grid. The “risk-based contingency chart” allows the system operator to analyze contingency cases from the probability and impact aspect in one chart. Both tools may be used in the control room for improved operational planning. In this study of contingency analysis and various types of network studies of severity factor quantification, the IEEE 39-Bus sample network is used in Power-Factory to analyze the contingencies behavior under different operational scenarios.

Operational risk assessment is a stochastic approach to quantify the operational security of power systems. In this study, the interrelation between severity factor and operational risk, two important parameters in operational risk assessment, is analyzed. Four different definitions of severity factor, based on the results from network studies, are proposed and applied, resulting in different values for the operational risk indices. The behavior of these indices is analyzed under varying operating conditions and compared with the behavior of the severity factor for individual contingencies. This study confirms the importance of the severity factor definition and shows that multiple operational risk indices are required to obtain a clear picture of the operational security of a transmission system. One risk index may increase while another decreases.

This paper gives an overview of the components and failure modes that should be considered when studying the reliability of grid-size Battery Energy Storage System (BESS). Next to failures of the primary component, a reliability study should consider the failure of the protection, failure of the communication, and failure of the control system. After all the diagnosed failures, qualitative fault tree analysis (FTA) based on Boolean logic is introduced as a basis of further analysis. Storage installations have a number of applications, each of which requires a different look at the reliability. The following applications are discussed in the paper: improving supply reliability, compensation power flows, market participation and frequency control.