Renewables from a TSO Perspective M.BENA, SmartGrids Director, RTE, French TSO Vienna, 18 May 2015
RTE in Europe 8500 employees Owner and Operator of the Assets 100 000 km UHV and HV lines (400 kv -> 63 kv) Consumption ~ 480TWh State-owned company Largest TSO in Europe 46 interconnections
Context (1/2) A major evolution of the electric system is in progress Today : The electric System used to rely on large synchronous power plants, able to ensure the generation/demand balance and provide ancillary services (voltage control, frequency control) Tomorrow : Generation mix will include many decentralized and little generation means, interfaced with inverter-based components. They will be less predictable, more variable and less controllable. => As a consequence : changes are needed to ensure the reliabily of the System and solutions have to be found at the European Level. ENTSO-E identified several ways to make progress : Develop a more robust Transmission Grid and a more efficient Market Design, able to get advantage of all efficient flexibilities Increase the Flexibility of Consumers and Generators Develop Smarter Control Centers to optimize the use of infrastructures GridCodes are a key element 3
Context (2/2) Connection Requirements for generators (RfG) Demand Connection Code (DCC) NC HVDC Market Capacity Alloction and Congestion Management (CACM) Forward Capacity Allocation (FCA) Electricity Balancing (EB) Operation Operational Security Principles (OS) Operational Planning and Scheduling (OPS) Load Frequency Control and Reserves (LFC) «Connected» Codes Connection Codes define the requirements of the installations Operation Codes define the use of these capacities for the System needs Market Codes define Designs to take advantage of the use of the available capacities 4
The question is What is the «critical» levels of integration of Renewables in the European Mix? Noone knows but Integration of significant proportion of RES into the grid is technically and economically possible with Adapted rules for connection, more flexibility and services from RES Dedicated tools and accurate forecasts, Coordination between Distribution and Transmission System Operators (DSO and TSO) Research Projects and coordination between European TSO to integrate these productions at a large scale.
Requirement for Generators (RfG) Code It sets the expected performances for the contribution to the Electric System security All generators have a role to play, depending on their characteristics One main objective is to avoid a massive lost of small generating units following a disturbance on the system Main fields where PV units will contribute are : Frequency - ability to stay connected between 47,5 Hz and 51,5 Hz - ability to control the generated power, in case of under or over frequency - for large units, technical ability to contribute to frequency control - for large units, if the TSO needs it, ability to generate inertia Voltage Control, for large units - ability to stay connected in a predefined range, for units connectes to high voltage grid - ability to control reactive power - ability to contribute to voltage control Grid Stability - ability to go through a voltage dip - reactive injection in case of contingency
Significant grid users defined by each TSO RPT RPD D C B PD<75 MW Ou U>110 kv PC<50MW PB<1MW Requirements for frequency control (frequency ranges, limited frequency sensitive mode, ROCOF ) Requirements for automatic control (FRT capability, ) Active contribution for frequency and voltage controls A 800W The GridCode gives a definition for these four categories mais let each country give more precise national ranges (ongoing discussions in France)
PV in future : Grid Code Requirements Requirements for Generators (RfG): Wind farm, PV, synchronous machine. depends on capacity (MW) and voltage in connection point PV will participate in : - voltage control - frequency control - synthetic inertia - fast reactive current injection
A balance at any time Between demand and production On behalf of users of the electricity transmission system Imbalances due to outages of power plants, error forecasts of demand or RES Considering also exchanges on interconnections Impact on balancing Demand Balancing by RTE Schedules of Production Balancing Mechanism With conventional productions and consumers directly connected to the transmission grid RES are excluded of the BM 9
Influence of RES on interconnections
Reserves and RES forecasts Reserves have to be available To ensure this balance and the security of the system Operational reserves (MW) RES generation and size of tertiary reserves Forecast error for wind and PV production taken into account in dimensioning total hazard RTE should cope with. Ancillary services (Automatic) PR SR >608 MW Tertiary reserve 500 to 800 MW sec 10 15 2h 8h PR: Primary Reserve (for Frequency Control) SR: Secondary Reserve (Load-Frequency Control) Time frame
The need for RES Supervision Impact on reserves Without previsions nor observations With previsions only With previsions and observations TimeFrame
IPES: a system dedicated to RES A tool to collect data relative to wind farms and to provide information to endusers in charge of managing the grid.
Monitoring wind generation with IPES A complete interface to provide different types of data, from measures to forecasts and location of the wind (+ PV) production. Geographical information about wind & PV farms (location, installed capacity, load factor ) Technical information (capacity, measures, forecasts ) Graph of production on a 6 days period (installed capacity, production estimation, forecasts )
IMPLEMENTATION PLAN 2016-2018 RESEARCH & DEVELOPMENT ROADMAP 2013 2022 Inertia, control and protection of large power systems with large share of inverter-based components The integration of large amounts of renewable generation with power electronic interfaces and introduction of HVDC links into the power system will necessitate a review of how to operate and control transmission networks. The goal of this topic is to investigate how power systems will behave when the transmission network is fed by large amounts of inverter-based generation, and identify what must be done to allow this equipment to be integrated into the system safely. More and more components in the European power system are based on power electronics. This equipment feeds harmonic current into the system that, in some cases, can lead to unstable behaviour and impair the reliability of the power system. Entire areas might potentially be fed only by inverter-based generation, such as from HVDC offshore energy. Therefore, fault detection, power system stability and control, de-rating of transformers due to higher harmonics and harmonic distortion must all be studied. Appropriate tools and methods for building models must be identified for this purpose. Current control and protection schemes must be reviewed and may need to be redefined to allow stable, reliable and economic operation of the network. Expected Impact Maximising the volume of renewable generation input whilst keeping the system stable Anticipation of future potential problems Clarification of how this may lead to new control / projection schemes and definition of grid connection rules
Thanks! Michel.bena@rte-france.com