Individual Grid Model (IGM)

Commission Regulation (EU) 2015/1222 of 24 July 2015 establishing a Guideline on Capacity Allocation and Congestion Management - CACM (Regulation on market coupling)

Article 19

Individual grid model

1. For each bidding zone and for each scenario:

(a) all TSOs in the bidding zone shall jointly provide a single individual grid model which complies with Article 18(3); or

(b) each TSO in the bidding zone shall provide an individual grid model for its control area, including interconnections, provided that the sum of net positions in the control areas, including interconnections, covering the bidding zone complies with Article 18(3).

2. Each individual grid model shall represent the best possible forecast of transmission system conditions for each scenario specified by the TSO(s) at the time when the individual grid model is created.

3. Individual grid models shall cover all network elements of the transmission system that are used in regional operational security analysis for the concerned time-frame.

4. All TSOs shall harmonise to the maximum possible extent the way in which individual grid models are built.

5. Each TSO shall provide all necessary data in the individual grid model to allow active and reactive power flow and voltage analyses in steady state.

6. Where appropriate, and upon agreement between all TSOs within a capacity calculation region, each TSO in that capacity calculation region shall exchange data between each other to enable voltage and dynamic stability analyses.

Network Code on Forward Capacity Allocation

Article 20
Individual grid model

When developing the individual grid model for a long-term capacity calculation timeframe in capacity calculation regions, where security analysis based on multiple scenarios pursuant to Article 10 is applied, each TSO shall apply the requirements set in Article 19 of Commission Regulation (EU) 2015/1222.

Network Code on System Operation, Articles 64 - 71

Article 64
General provisions regarding individual and common grid models

1.   To perform operational security analysis pursuant to Title 2 of this Part, each TSO shall prepare individual grid models in accordance with the methodologies established in application of Article 17 of Regulation (EU) 2015/1222 and Article 18 of Regulation (EU) 2016/1719 for each of the following time-frames, applying the data format established pursuant to Article 114(2):
(a) year-ahead, in accordance with Articles 66, 67 and 68;
(b) where applicable, week-ahead, in accordance with Article 69;
(c) day-ahead, in accordance with Article 70; and
(d) intraday, in accordance with Article 70.

2.   The individual grid models shall include the structural information and data set out in Article 41.

3.   Each TSO shall build the individual grid models and each regional security coordinator shall contribute to building the common grid models applying the data format established pursuant to Article 114(2).

Article 65
Year-ahead scenarios

1.   All TSOs shall jointly develop a common list of year-ahead scenarios against which they assess the operation of the interconnected transmission system for the following year. Those scenarios shall allow the identification and the assessment of the influence of the interconnected transmission system on operational security. The scenarios shall include the following variables:
(a) electricity demand;
(b) the conditions related to the contribution of renewable energy sources;
(c) determined import/export positions, including agreed reference values allowing the merging task;
(d) the generation pattern, with a fully available production park;
(e) the year-ahead grid development.

2.   When developing the common list of scenarios, TSOs shall take into account the following elements:
(a) the typical cross-border exchange patterns for different levels of consumption and of renewable energy sources and conventional generation;
(b) the probability of occurrence of the scenarios;
(c) the potential deviations from operational security limits for each scenario;
(d) the amount of power generated and consumed by the power generating facilities and demand facilities connected to distribution systems.

3.   Where TSOs do not succeed in establishing the common list of scenarios referred to in paragraph 1, they shall use the following default scenarios:
(a) Winter Peak, 3rd Wednesday of January current year, 10:30 CET;
(b) Winter Valley, 2nd Sunday of January current year, 03:30 CET;
(c) Spring Peak, 3rd Wednesday of April current year, 10:30 CET;
(d) Spring Valley, 2nd Sunday of April current year, 03:30 CET;
(e) Summer Peak, 3rd Wednesday of July previous year, 10:30 CET;
(f) Summer Valley, 2nd Sunday of July previous year, 03:30 CET;
(g) Autumn Peak, 3rd Wednesday of October previous year, 10:30 CET;
(h) Autumn Valley, 2nd Sunday of October previous year, 03:30 CET.

4.   ENTSO for Electricity shall publish every year, by 15 July, the common list of scenarios established for the following year, including the description of those scenarios and the period during which these scenarios are to be used.

Article 66
Year-ahead individual grid models

1.   Each TSO shall determine a year-ahead individual grid model for each of the scenarios developed pursuant to Article 65, using its best estimates of the variables defined in Article 65(1). Each TSO shall publish its year-ahead individual grid models on the ENTSO for Electricity operational planning data environment in accordance with Article 114(1).

2.   When defining its year-ahead individual grid model, each TSO shall:
(a) agree with the neighbouring TSOs upon the estimated power flow on HVDC systems linking their control areas;
(b) balance for each scenario the sum of:
(i) net exchanges on AC lines;
(ii) estimated power flows on HVDC systems;
(iii) load, including an estimation of losses; and
(iv) generation.

3.   Each TSO shall include in its year-ahead individual grid models the aggregated power outputs for power generating facilities connected to distribution systems. Those aggregated power outputs shall:
(a) be consistent with the structural data provided in accordance with the requirements of Articles 41, 43, 45 and 48;
(b) be consistent with the scenarios developed in accordance with Article 65; and
(c) distinguish the type of primary energy source.

Article 67
Year-ahead common grid models

1.   By 6 months after entry into force of this Regulation, all TSOs shall jointly develop a proposal for the methodology for building the year-ahead common grid models from the individual grid models established in accordance with Article 66(1) and for saving them. The methodology shall take into account, and complement where necessary, the operational conditions of the common grid model methodology developed in accordance with Article 17 of Regulation (EU) 2015/1222 and Article 18 of Regulation (EU) 2016/1719, as regards the following elements:
(a) deadlines for gathering the year-ahead individual grid models, for merging them into a common grid model and for saving the individual and common grid models;
(b) quality control of the individual and common grid models to be implemented in order to ensure their completeness and consistency; and
(c) correction and improvement of individual and common grid models, implementing at least the quality controls referred to in point (b).

2.   Each TSO shall have the right to request from another TSO any information on modifications to the network topology or on operational arrangements, such as protection setpoints or system protection schemes, single line diagrams and configuration of substations or additional grid models relevant for the provision of an accurate representation of the transmission system to undertake operational security analysis.

Article 68
Updates of year-ahead individual and common grid models

1.   When a TSO modifies or notices a modification of its best estimates for the variables used for determining its year-ahead individual grid model established in accordance with Article 66(1), which is significant for operational security, it shall update its year-ahead individual grid model and publish it on the ENTSO for Electricity operational planning data environment.

2.   Whenever an individual grid model is updated, the year-ahead common grid model shall be updated accordingly applying the methodology determined in accordance with Article 67(1).

Article 69
Week-ahead individual and common grid models

1.   Where two or more TSOs consider it necessary, they shall determine the most representative scenarios for coordinating the operational security analysis of their transmission system for the week-ahead time-frame and shall develop a methodology for merging the individual grid models analogous to the methodology for building the year-ahead common grid model from year-ahead individual grid models in accordance with Article 67(1).

2.   Each TSO referred to in paragraph 1 shall establish or update its week-ahead individual grid models pursuant to the scenarios determined in accordance with paragraph 1.

3.   The TSOs referred to in paragraph 1 or the third parties to which the task referred to in paragraph 1 has been delegated, shall build the week-ahead common grid models following the methodology developed in accordance with paragraph 1 and using the individual grid models established in accordance with paragraph 2.

Article 70
Methodology for building day-ahead and intraday common grid models

1.   By 6 months after entry into force of this Regulation, all TSOs shall jointly develop a proposal for the methodology for building the day-ahead and intraday common grid models from the individual grid models and for saving them. That methodology shall take into account, and complement where necessary, the operational conditions of the common grid model methodology developed in accordance with Article 17 of Regulation (EU) 2015/1222, as regards the following elements:
(a) definition of timestamps;
(b) deadlines for gathering the individual grid models, for merging them into a common grid model and for saving individual and common grid models. The deadlines shall be compatible with the regional processes established for preparing and activating remedial actions;
(c) quality control of individual grid models and the common grid model to be implemented to ensure their completeness and consistency;
(d) correction and improvement of individual and common grid models, implementing at least the quality controls referred to in point (c); and
(e) handling additional information related to operational arrangements, such as protection setpoints or system protection schemes, single line diagrams and configuration of substations in order to manage operational security.

2.   Each TSO shall create day-ahead and intraday individual grid models in accordance with paragraph 1 and publish them on the ENTSO for Electricity operational planning data environment.

3.   When creating the day-ahead or intraday individual grid models referred to in paragraph 2, each TSO shall include:
(a) up-to-date load and generation forecasts;
(b) the available results of the day-ahead and intraday market processes;
(c) the available results of the scheduling tasks described in Title 6 of Part III;
(d) for power generating facilities connected to distribution systems, aggregated active power output differentiated on the basis of the type of primary energy source, in line with data provided in accordance with Articles 40, 43, 44, 48, 49 and 50;
(e) up-to-date topology of the transmission system.

4.   All remedial actions already decided shall be included in the day-ahead and intraday individual grid models and shall be clearly distinguishable from the injections and withdrawals established in accordance with Article 40(4) and the network topology without remedial actions applied.

5.   Each TSO shall assess the accuracy of the variables in paragraph 3 by comparing the variables with their actual values, taking into account the principles determined pursuant to Article 75(1)(c).

6.   If, following the assessment referred to in paragraph 5, a TSO considers that the accuracy of the variables is insufficient to evaluate operational security, it shall determine the causes of the inaccuracy. If the causes depend on the TSO's processes for establishing the individual grid models, that TSO shall review those processes to obtain more accurate results. If the causes depend on variables provided by other parties, that TSO together with those other parties shall endeavour to ensure that the variables concerned are accurate.

Article 71
Quality control for grid models

When defining the quality controls in accordance with Articles 67(1)(b) and 70(1)(c), all TSOs shall jointly determine controls aimed at least to check:
(a) the coherence of the connection status of interconnectors;
(b) that voltage values are within the usual operational values for those transmission system elements having influence on other control areas;
(c) the coherence of transitory admissible overloads of interconnectors; and
(d) that active power and reactive power injections or withdrawals are compatible with usual operational values.