The aim of this tutorial is to provide the participants with the necessary technical and regulatory understanding on the following two aspects:

• Ancillary Services in Systems with High VRE Shares:
  How traditional services may have to be reshaped to guarantee a safe, secure and reliable operation of a changing power system. Introduction to innovative ancillary services such as ramping reserve or fast frequency response.

• VRE Participation in the Provision of Ancillary Services:
  Technology and infrastructure needs to enable VRE participation in ancillary services.

Examples on international best practices on the above mentioned topics will also be provided within the tutorial. Find a more detailed description here.

Ancillary services are those services provided by generation, transmission and control equipment which are necessary to support the transmission of electric power from producer to purchaser ensuring a safe, secure and reliable operation of the power system. Ancillary services include services intended to ensure frequency stability by balancing short term deviations between load and generation, such as reserves, services that provide control of the voltage, such as reactive power, and emergency services such as black start capability.

Ancillary services are gaining importance in the context of uptaking variable renewable energy sources (VRE) as tools towards achieving a successful transition from conventional based generation systems to VRE dominated systems. These services themselves are also undergoing a transformation and are being reviewed and updated by system operators in order to continue serving the needs of the power systems where the inherent characteristics of VRE such as their variability and uncertainty, their locational nature or their lack of inertial response are becoming more present in their operation.

Find below a detailed description of the issues touched in these tutorials:

Session 1: Ancillary Services in Systems with High VRE Shares

The first 60 minutes block will introduce how ancillary services must be reshaped to guarantee a safe, secure and reliable electric supply in the power systems with high VRE penetration. The presentation will include example of best international practices addressing, at least, the cases of Ireland, California and Germany. Click on the content button for a detailed list of topics.

Content:

• Introduction to Ancillary Services
• Frequency Control:
  • Traditional services:
    • Purpose, activation and dimensioning of reserves;
    • Service providers;
    • Reserve procurement frameworks;
  • Impact of rising VRE shares on frequency control:
    • Reduced inertia and higher RoCoF;
    • More frequent activation;
    • Scarcity of traditional service providers: Which technologies can replace conventional generation in the provision of ancillary services?
  • Innovative services and new market mechanism in the context of VRE: Real time markets and their impact on ancillary services, inertia products, fast frequency response, synthetic inertia and ramping reserves.
• Voltage control:
  • Capabilities of conventional and VRE generators;
  • Control schemes;
  • Cost and procurement;
  • Impact of VRE on reactive power demand and voltage control schemes.

• Black start:
  • Basics of black start plans and analysis of example cases;
  • The role of black starting and houseload units;
  • Changes in black start plans incurred by high shares of VRE.

Session 2: VRE Participation in the Provision of Ancillary Services

Based on the understanding of the issues developed in Session 1, in the second thematic block the participants will be introduced to the technical and regulatory aspects on how VRE and converter-based technologies in general can participate in the provision of ancillary services. Click on the content button for a detailed list of topics.

Content:

• VRE participation in balancing and frequency control:
  • Inverter capabilities and infrastructure needed;
  • Fast frequency response;
  • Upward reserve provision: Delta control;
  • Ancillary service market issues.
• VRE participation in voltage control:
  • Reactive power capability of inverters;
  • Reactive power control modes;
• Participation of distributed generation in ancillary services:
  • Smart Inverters: IEEE 1458;
  • Role of Aggregators;
  • Virtual power plants;
  • Black start support with cellular approach.
• Grid Forming Inverters:
  • Are they really needed?
  • Is the technology ready?
  • How can grid forming inverters improve ancillary service provision?