Coordinated Security Analysis (CSA) is one of core RSC services with the main purpose to identify operational security risks. CSA process is performed in two forecast horizons:
- Day Ahead Congestion Forecast (DACF) and
- Intraday Congestion Forecast (IDCF) procedure.
After creating Common Grid Models (CGMs), SCC continues the DACF and IDCF procedure by conducting security analysis. Beside CGMs, input data for CSA process are Contingencies and Critical Network Elements (CNE). Contingency represents the network element (lines, transformers, nodes, generators, loads, etc.) for which specific TSO wants to simulate its disconnection from the network in order to obtain information about potential congestion after disconnection. In some cases, TSOs request simulation of disconnection of multiple simultaneous elements which could occur in real life (e.g. disconnection of parallel lines on same line corridor). These N-X disconnections are also simulated in SCC’s security analysis. On the other hand, CNE represents important network element which overload (after given Contingency) could jeopardize national or regional security of supply. During each simulation of N-X Contingency, our tool is continually monitoring CNEs in order to detect potential security issues.
SCC performs security analysis at four times a day – once for the upcoming 24 hours in DACF procedure and three times for upcoming eight hours within the IDCF process. The security analysis is done on a CGM of Continental Europe. The results of the security analysis are forwarded to the TSO service users at the end of the DACF and IDCF procedures in the form of statistical reports. Based on the CSA results, TSOs are in position to get a deep insight into system state before real time and, in case of need, to prepare network for taking the necessary remedial actions.
By obtaining new operational software tool during 2020, SCC gets the opportunity to provide TSO service users with the ability to simulate Remedial Actions (RAs). For each pair of Critical Network Element and Contingency (CNEC), TSOs are in position to provide potential RAs, which are activated in the CGM only if CNE is overloaded after simulation of given Contingency. The goal of RAs is to provide insight to TSOs how potential congestions could be solved.
In cases when one CNEC pair has more than one proposed RAs, SCC is in position to propose best solution by performing Remedial Action Optimisation (RAO) process. Objective function of this optimisation process can include decrease of network elements loading after RA activation as well as RA activation cost, and it will be definitely improved in upcoming period with close cooperation with TSO service users.
Currently high-level general scheme for day-ahead CSA process, proposed by ENTSO-E expert team, is presented below. Basically, it contains two CSA runs with the same steps:
- Input data preparation by TSOs;
- Consistency check of CSA input data;
- CGM building process done by one main RSC (determined on rotational principle using predefined schedule);
- Regional security assessment and RAO process performed by each regional RSCs;
RA coordination process performed either on Pan-European or regional level (to be decided).
The goal of the second run of CSA process is to provide recalculation of security analysis results after the implementation of agreed RAs after the first RA coordination process. Namely, after first RAO process, TSOs are provided with a set of optimal RAs, for which concerned TSOs should provide response – do they agree with potential activation of these actions or not. If all concerned TSOs agree about potential activation of certain preventive RA, then this RA should be applied in the CSA input data for the second run. After RA coordination in the second run, final RA validation session is used to conclude CSA process with a set of agreed RAs that will be applied in real time if expected congestion really occurs.