Final Report on the local power grid incident in Rogowiec (Poland) substation on 17 May 2021

The Expert Panel composed of ENTSO-E, Polskie Sieci Elektroenergetyczne S.A. (PSE, the Polish Transmission System Operator (TSO)), ACER and relevant National Regulatory Authority (NRA) representatives publish their Final Report on the Local Grid Incident in Rogowiec (Poland) substation that occurred on 17 May 2021, issued in accordance with the System Operation Guideline (SO GL) and the Incident Classification Scale (ICS) Methodology.

The report is published on the ENTSO-E website.

The incident – classified as a scale 2 incident according to the ICS Methodology – led to the tripping of ten generation units of the Bełchatów power plant and to a loss of 3,322 MW of generation capacity. The cause of the incident was a human error. Incorrect manipulation of the line earthing switch led to a short circuit in the 400 kV Rogowiec switchyard.

Thanks to the swift remedial actions taken by PSE, as well as the emergency support from neighbouring TSOs and cooperation with the coordination centre, the power system was operating within the security limits for approximately 20 minutes. The market continued to function according to the standard procedures in all timeframes. No consumer was disconnected and there was no negative impact on the operation of the synchronously interconnected power system of Continental Europe.

Following the investigation, the Expert Panel presents its report which includes a few recommendations.

Recommendations of the Expert Panel

1. In substations where a large-scale incident can lead to more than 3000 MW of generation lost, the TSO shall:

• Possess a document showing the compliance of the grounding circuits to technical requirements coming from the tests done during the commissioning of the substation, or

• Possess a document showing the compliance of the grounding circuits to technical requirements coming from the tests done after any substantial modifications of the grounding circuits, or

• Measure and check the compliance of the grounding circuits to technical requirements in case documents mentioned in paragraphs a. and b. are not available.

2. In order to guarantee a better resilience, in the relevant substations and double lines of the network which can cause at least scale 2 incident according to ICS methodology, have a dedicated reinforced maintenance of these structures.

Notes

1. Incident Classification Scale. The ICS Methodology has been developed in accordance with Regulation (EU) 2019/943 of the European Parliament and of the Council of 5 June 2019. It was updated in 2019, to fulfil the objectives of Article 15 of SO GL quoted above.

2. Commission Regulation (EU) 2017/1485 of 2 August 2017 establishing a guideline on electricity transmission system operation (System Operation Guideline, SO GL).