Description
In parallel with the liberalization of the energy markets, the decentralized generation of electrical power and heating and air conditioning energy becomes more and more important. The generation of these types of energy near to the consumers offers economic and ecological benefits. In this context, interest is directed to so-called virtual power plants. A virtual power plant is a collection of small and very small decentralized generation units that is monitored and controlled by a super-ordinated energy management system. In general, these generation units produce heating and air conditioning energy as well as electricity. A successful operation of a virtual power plant requires the following technical equipment:
a) an energy management system that monitors, plans and optimizes the operation of the decentralized power units;
b) a forecasting system for loads that is able to calculate very short-term forecasts (one hour) and long-term forecasts (up to seven days);
c) a forecasting system for the generation of renewable energy units. This forecast uses weather forecasts in order to predict the generation of wind power plants and photovoltaics;
d) an energy data management system which collects and keeps the data that is required for optimization and forecasts, for example, profiles of generation and loads as well as contractual data for customer supply;
e) a powerful front end for the communication of the energy management system with the decentralized power units.
First, a virtual power plant needs a bidirectional communication between the decentralized power units and the control centre of the energy management system. For larger units, control systems based on protocols such as IEC 61850 or IEC 61400 can be used. In the future, with an increasing number of small decentralized power units, communication channels and protocols will play a more important role. It is likely that the costly conventional telemetry technique will be substituted by other techniques based on simple TCP/IP adapters or based on power line carrier techniques.
All operation planning and scheduling applications require forecasts with sufficient accuracy.
The special structure of a virtual power plant places high demands on the mathematical models for the optimization. The models need to be very precise because rough models could yield optimization results that cannot be realized by the power system. Because the virtual power plant has to provide an automatic mode for online control of the decentralized power units, e.g. for compensating imbalances, no operator can check and correct the results.
The components/units of a virtual power plant and their energy flow topology are modelled in DER by some classes of model elements, e.g. converter units, contracts, storage units, renewable units and flexible loads.
The DER control applications provide control and supervision capability of all generation units, storage units and flexible demands, as well as control capability to maintain an agreed-upon electrical interchange energy profile.
The functions of VPP/DER can be subdivided into planning functions and control functions. The respective planning functions are:
· weather
forecast;
· load forecast;
· generation
forecast;
· unit commitment;
· generation
and load management.
Generation management functions allow for the control and supervision of all generation and storage units of the virtual power plant. Dependent on the control mode of the respective unit (independent, manual, schedule or control mode) and the unit parameters (minimum/maximum power, power gradients, energy content), the actual state (start-up, online, remote controllable, disturbed) and the actual power output of the unit, the start/stop commands and power set points for the units are calculated and transmitted. In the event of a unit disturbance, the generation management can start a spontaneous unit commitment calculation to force a rescheduling of the remaining units under the changed circumstances while also considering all integral constraints.
Load management functions allow the control and supervision of all flexible loads in the virtual power plant.
In parallel with the liberalization of the energy markets, the decentralized generation of electrical power and heating and air conditioning energy becomes more and more important. The generation of these types of energy near to the consumers offers economic and ecological benefits. In this context, interest is directed to so-called virtual power plants. A virtual power plant is a collection of small and very small decentralized generation units that is monitored and controlled by a super-ordinated energy management system. In general, these generation units produce heating and air conditioning energy as well as electricity. A successful operation of a virtual power plant requires the following technical equipment:
a) an energy management system that monitors, plans and optimizes the operation of the decentralized power units;
b) a forecasting system for loads that is able to calculate very short-term forecasts (one hour) and long-term forecasts (up to seven days);
c) a forecasting system for the generation of renewable energy units. This forecast uses weather forecasts in order to predict the generation of wind power plants and photovoltaics;
d) an energy data management system which collects and keeps the data that is required for optimization and forecasts, for example, profiles of generation and loads as well as contractual data for customer supply;
e) a powerful front end for the communication of the energy management system with the decentralized power units.
First, a virtual power plant needs a bidirectional communication between the decentralized power units and the control centre of the energy management system. For larger units, control systems based on protocols such as IEC 61850 or IEC 61400 can be used. In the future, with an increasing number of small decentralized power units, communication channels and protocols will play a more important role. It is likely that the costly conventional telemetry technique will be substituted by other techniques based on simple TCP/IP adapters or based on power line carrier techniques.
All operation planning and scheduling applications require forecasts with sufficient accuracy.
The special structure of a virtual power plant places high demands on the mathematical models for the optimization. The models need to be very precise because rough models could yield optimization results that cannot be realized by the power system. Because the virtual power plant has to provide an automatic mode for online control of the decentralized power units, e.g. for compensating imbalances, no operator can check and correct the results.
The components/units of a virtual power plant and their energy flow topology are modelled in DER by some classes of model elements, e.g. converter units, contracts, storage units, renewable units and flexible loads.
The DER control applications provide control and supervision capability of all generation units, storage units and flexible demands, as well as control capability to maintain an agreed-upon electrical interchange energy profile.
The functions of VPP/DER can be subdivided into planning functions and control functions. The respective planning functions are:
• weather forecast;
• load forecast;
• generation forecast;
• unit commitment;
• generation and load management.
Generation management functions allow for the control and supervision of all generation and storage units of the virtual power plant. Dependent on the control mode of the respective unit (independent, manual, schedule or control mode) and the unit parameters (minimum/maximum power, power gradients, energy content), the actual state (start-up, online, remote controllable, disturbed) and the actual power output of the unit, the start/stop commands and power set points for the units are calculated and transmitted. In the event of a unit disturbance, the generation management can start a spontaneous unit commitment calculation to force a rescheduling of the remaining units under the changed circumstances while also considering all integral constraints.
Load management functions allow the control and supervision of all flexible loads in the virtual power plant.
Available standards
The standards listed below are available on IEC webstore.
|
Layer |
Standard |
Comments |
|
Information |
IEC 61850-7-4 IEC 61850-7-3 IEC 61850-7-2 IEC 61850-6 |
Communication networks and systems for power utility automation Core Information model and language for the IEC 61850 series |
|
Information |
IEC 61850-7-410 |
Communication networks and systems for power utility automation – Part 7-410: Basic communication structure – Hydroelectric power plants – Communication for monitoring and control |
|
Information |
IEC 61850-7-420 |
Communication networks and systems for power utility automation – Part 7-420: Basic communication structure – Distributed energy resources logical nodes |
|
Information |
IEC 61850-7-420 |
Communication networks and systems for power utility automation - Part 7-420: Basic communication structure - Distributed energy resources and distribution automation logical nodes |
|
Information |
IEC TR 61850-90-3 |
Communication networks and systems for power utility automation – Part 90-3: Using IEC 61850 for condition monitoring diagnosis and analysis |
|
Information |
IEC TS 61850-80-1 |
Communication networks and systems for power utility automation – Part 80-1: Guideline to exchanging information from a CDC-based data model using IEC 60870-5-101 or IEC 60870-5-104 IEC 61850 communication except Sample values |
|
Information |
IEC TS 61850-80-4 |
Communication networks and systems for power utility automation – Part 80-4: Translation from the COSEM object model (IEC 62056) to the IEC 61850 data model |
|
Information |
IEC 61400-25 series |
Wind turbines – Communications for monitoring and control of wind power plants – Information models |
|
Information |
IEC 61968 series |
Application integration at electric utilities – System interfaces for distribution management Common Information Model (System Interfaces For Distribution Management) |
|
Information |
IEC 61970 series |
Energy management system application program interface (EMS-API) Common Information Model (System Interfaces For Energy Management) |
|
Communication |
IEC 61850-8-1 |
Communication networks and systems for power utility automation – Part 8-1: Specific communication service mapping (SCSM) – Mappings to MMS (ISO 9506-1 and ISO 9506-2) and to ISO/IEC 8802-3 IEC 61850 communication except Sample values |
|
Communication |
IEC 61850-8-2 |
Communication networks and systems for power utility automation – Part 8-2: Specific communication service mapping (SCSM) – Mappings to web-services |
|
Communication |
IEC 61850-9-2 |
Communication networks and systems for power utility automation – Part 9-2: Specific communication service mapping (SCSM) – Sampled values over ISO/IEC 8802-3 IEC 61850 Sample values communication |
|
Communication |
IEC/IEEE 61850-9-3 |
Communication networks and systems for power utility automation – Part 9-3: Precision time protocol profile for power utility automation |
|
Communication |
IEC TR 61850-90-1 |
Communication networks and systems for power utility automation – Part 90-1: Use of IEC 61850 for the communication between substations |
|
Information, Communication |
IEC TR 61850-90-2 |
Communication networks and systems for power utility automation – Part 90-2: Using IEC 61850 for the communication between substations and control centres |
|
Communication |
IEC 60870-5-101 |
Telecontrol equipment and systems – Part 5-101: Transmission protocols – Companion standard for basic telecontrol tasks |
|
Communication |
IEC 60870-5-103 |
Telecontrol equipment and systems – Part 5-103: Transmission protocols – Companion standard for the informative interface of protection equipment |
|
Communication |
IEC 60870-5-104 |
Telecontrol equipment and systems – Part 5-104: Transmission protocols – Network access for IEC 60870-5-101 using standard transport profiles |
|
Information, Communication |
IEC TR 61850-90-4 |
Part 90-4: Network engineering guidelines for communication within substation – Network management |
|
Communication |
IEC TR 61850-90-5 |
Communication networks and systems for power utility automation – Part 90-5: Use of IEC 61850 to transmit synchrophasor information according to IEEE C37.118 May also be relevant for use between substations |
|
Communication |
IEC 60255-24 |
Measuring relays and protection equipment – Part 24: Common format for transient data exchange (COMTRADE) for power systems |
|
Information |
IEC TR 61850-90-11 |
Communication networks and systems for power utility automation – Methodologies for modelling of logics for IEC 61850 based applications |
|
Communication |
IEC TR 61850-90-12 |
Communication networks and systems for power utility automation – Part 90-12: Wide area network engineering guidelines |
|
Component |
IEC 62271-3 |
High-voltage switchgear and controlgear – Part 3: Digital interfaces based on IEC 61850 |
|
Communication |
IEC 62439 series |
Industrial communication networks – High availability automation networks (including PRP and HSR) |
|
Component |
IEC 61869 series |
Instrument transformers |
|
Communication |
IEC 62351 series |
Power systems management and associated information exchange – Data and communications security Cyber-security aspects (see 4.10.4) |
|
Information |
IEC TS 62361-102 |
Power systems management and associated information exchange - Interoperability in the long term - Part 102: CIM - IEC 61850 harmonization |
|
Component |
IEC 62689 series |
Current and voltage sensors or detectors, to be used for fault passage indication purposes |
|
Information, Communication |
IEC TR 61850-90-6 |
Communication networks and systems for power utility automation – Use of IEC 61850 for distribution automation systems |
|
Other specifications |
||
|
Communication |
IEEE 1815 |
Also known as DNP3 |
|
Information |
IEEE 1815-1 |
Mapping of IEC 61850 data model over DNP3 |
|
Layer |
Standard |
Title and comments |
|
Information |
IEC 61850-7-4 IEC 61850-7-3 IEC 61850-7-2 IEC 61850-6 |
Communication networks and systems for power utility automation Core Information model and language for the IEC 61850 series |
|
Information |
IEC 61400-25-2 |
Wind turbines – Part 25-2: Communications for monitoring and control of wind power plants – Information models |
|
Information |
IEC 61400-25-3 |
Wind turbines – Part 25-3: Communications for monitoring and control of wind power plants – Information exchange models |
|
Information |
IEC 61850-7-410 |
Communication networks and systems for power utility automation – Part 7-410: Hydroelectric power plants – Communication for monitoring and control |
|
Information |
IEC 61850-7-420 |
Communication networks and systems for power utility automation – Part 7-420: Basic communication structure – Distributed energy and distribution automation resources logical nodes |
|
Information |
IEC TR 61850-90-7 |
Communication networks and systems for power utility automation – Part 90-7: Object models for power converters in distributed energy resources (DER) systems Edition 2 (planned for 2023) will be an editorial revision consistent with IEC 61850-7-420:2021. |
|
Information |
IEC TR 61850-90-9 |
Use of IEC 61850 for electrical storage systems |
|
Information |
IEC TR 61850-90-11 |
Methodologies for modelling of logics for IEC 61850 based applications |
|
Communication |
IEC 60870-5-101 |
Telecontrol equipment and systems – Part 5-101: Transmission protocols – Companion standard for basic telecontrol tasks |
|
Communication |
IEC 60870-5-104 |
Telecontrol equipment and systems – Part 5-104: Transmission protocols – Network access for IEC 60870-5-101 using standard transport profiles |
|
Communication |
IEC 61850-8-1 |
Communication networks and systems for power utility automation – Part 8-1: Specific communication service mapping (SCSM) – Mappings to MMS (ISO 9506-1 and ISO 9506-2) and to ISO/IEC 8802-3 IEC 61850 communication except Sample values |
|
Communication |
IEC TR 61850-80-3 |
Communication networks and systems for power utility automation - Part 80-3: Mapping to web protocols - Requirements and technical choices |
|
Communication |
IEC 61850-8-2 |
Communication networks and systems for power utility automation – Part 8-2: Specific communication service mapping (SCSM) – Mappings to web-services |
|
Communication, Information |
IEC TR 61850-90-2 |
Communication networks and systems for power utility automation – Part 90-2: Using IEC 61850 for the communication between substations and control centres |
|
Communication |
IEC TR 61850-90-12 |
Communication networks and systems for power utility automation – Part 90-12: Wide area network engineering guidelines |
|
Communication |
IEC 61400-25-4 |
Wind turbines – Part 25-4: Communications for monitoring and control of wind power plants – Mapping to communication profile |
|
Communication |
IEC 61158 series |
Industrial communication networks – Fieldbus specifications |
|
Communication |
IEC 61784-1 |
Industrial communication networks – Profiles – Part 1: Fieldbus profiles |
|
Information |
IEC 61131 series |
Programmable controllers |
|
Information |
IEC 61499 series |
Function blocks |
|
Information |
IEC 61968 series |
Application integration at electric utilities – System interfaces for distribution management Common Information Model (System Interfaces For Distribution Management)
IEC 61968-5:2020 is the description of a set of functions that are needed for enterprise integration of DERMS functions. These exchanges are most likely between a DERMS and a DMS. |
|
Information |
IEC 61970 series |
Energy management system application program interface (EMS-API) Common Information Model (System Interfaces For Energy Management) |
|
Communication |
IEC 61968-100 |
Application integration at electric utilities – System interfaces for distribution management – Part 100: Implementation profiles Defines profiles for the communication of CIM messages using Web Services or Java Messaging System |
|
Communication |
IEC 62351 series |
Power systems management and associated information exchange – Data and communications security Cyber-security aspects (see 4.10.4) |
|
Component |
IEC 60904 series |
Photovoltaic devices |
|
Component |
IEC 61194 |
Characteristic parameters of stand-alone photovoltaic (PV) systems |
|
Component |
IEC 61724 |
Photovoltaic system performance monitoring – Guidelines for measurement, data exchange and analysis |
|
Component |
IEC 61730 series |
Photovoltaic (PV) module safety qualification |
|
Component |
IEC TS 61836 |
Solar photovoltaic energy systems – Terms, definitions and symbols |
|
Component |
IEC 61400-1 |
Wind turbines – Part 1: Design requirements |
|
Component |
IEC 61400-2 |
Wind turbines – Part 2: Design requirements for small wind turbines |
|
Component |
IEC 61400-3 |
Wind turbines – Part 3: Design requirements for offshore wind turbines |
|
Component |
IEC TS 62282 |
Fuel cell technologies |
|
Component |
IEC 62600 series |
Marine energy – Wave, tidal and other water current converters |
|
Component |
Refer to 4.8.2.3 |
Refer to 4.8.2.3 |
|
Information |
IEC TS 62786 series |
Distributed energy resources connection with the grid (whole series)
|
|
Information |
IEC TS 62898 series |
Microgrids Part 1 (2017): Guidelines for microgrid projects planning and specification Part 2 (2018) : Guidelines for operation Part 3-1 (2020) : Technical requirements - Protection and dynamic control |
|
Other specifications |
||
|
Communication |
IEEE 1815 |
IEEE Standard for Electric Power Systems Communications-Distributed Network Protocol (DNP3) |
|
Information |
IEEE 1815-1 |
IEEE Standard for Exchanging Information Between Networks Implementing IEC 61850 and IEEE Std 1815(TM) [Distributed Network Protocol (DNP3)] |
|
Component |
EN 50549 series |
CLC/TS 50549-1:2015 Requirements for generating plants to be connected in parallel with distribution networks - Part 1: Connection to a LV distribution network above 16 A
CLC/TS 50549-2:2015 : Requirements for generating plants to be connected in parallel with distribution networks - Part 2: Connection to a MV distribution network
|
Coming standards
|
Layer |
Standard |
Title and comments |
|
Information |
IEC TR 61850-7-520 |
Communication networks and systems for power utility automation - Part 7-520: Distributed energy resources modelling concepts and guidelines |
|
Information |
IEC TR 61850-90-23 |
Communication networks and systems for power utility automation – Part 90-23: Use of IEC 61850 for microgrid systems |
|
Information |
IEC TR 61850-90-27 |
Communication networks and systems for power utility automation – Part 90-27: Use of IEC 61850 for thermal energy systems connected to electric power grid |
|
Information |
IEC TS 61400-25-41 |
Wind turbines - Part 25-41: Communications for monitoring and control of wind power plants - Mapping to communication profile based on IEC 62541 (OPC UA) |
|
Information |
IEEE 1815-2 |
Standard Profile for Communications with Distributed Energy Resources (DERs) using IEEE Std 1815 [Distributed Network Protocol (DNP3)] |
|
Information |
IEC 62746-4 |
Systems interface between customer energy management system and the power management system - Part 4: Demand Side Resource Interface |
|
Information |
IEC 62898 |
Part 3-2: Technical requirements - Energy management systems Part 3-4 : Technical requirements - Monitoring and Control systems Part 4 (Ed 2) : Use cases |
|
Information |
IEC 62786-1 |
Distributed energy resources connection with the grid - Part 1: General requirements |
|
Information |
IEC 62786-2 |
Distributed energy resources connection with the grid – Part 2 Additional requirements for PV generation |
|
Information |
IEC 62786-3 |
Distributed energy resources connection with the grid – Part 3 Additional requirements for Stationary Battery Energy Storage System |
|
Information |
IEC TS 62786-41 ED1 |
Distributed energy resources connection with the grid – Part 41 Requirements for frequency measurement used to control DER and loads |
|
Information |
IEC TS 62786-42 ED1 |
Distributed energy resources connection with the grid – Part 42 Requirements for voltage measurement used to control DER and loads |
Mapping of standards
on the component layer
The component architecture, as presented in Figure above, covers all zones:
· the Process zone with the DERs, inverters and related sensors and actors;
· the Field zone with the DER unit controller;
· the Station zone with the DER plant controller;
· the Operation zone with the tVPP/EMS which may interact with the DSOs DMS in case of tVPP;
· the Enterprise zone with the cVPP which interacts with the market platform or directly with an energy retailer.
Mapping of standards
on the communication layer
IEC 61850-8-1 defines the communication for any kind of data flows except sample values. IEC TR 61850-90-2 defines the communication to the control centre with IEC 61850-8-2 defining web-services mappings. For the field/station to operations communication the IEC 61850 communication protocols are used.
IEC 60870-5-101 and IEC 60870-5-104 can also be used for vertical communication as shown in Figure above.
For the enterprise communication at the operation, enterprise and market zone the coming standard IEC 61968-100 will be used.
The IEC 61158 series defines industrial field bus communication and IEC 61968-100 communication at the operations and enterprise levels.
Please refer to IEC TR 63097:2017 section 4.10.4 for getting details on cyber-security standards and more specifically on where and how to apply the IEC 62351 series and/or other cyber-security mechanisms.
Mapping of standards
on the information layer
The information layer of DER operation, as presented in Figure above, is mostly based on the IEC 61850 information model.
IEC 61850-7-4 is the core part depicting this model which is extended by various standards for DER operations:
· IEC
61850-7-410: Hydroelectric power plants
· IEC 61850-7-420: Energy resources connected to the distribution
network
· IEC 61400-25-2/-3: Wind turbines
· IEC
TR 61850-90-9: Batteries
Specific standards for DER EMS/VPP operation at the enterprise bus are currently not defined.
Note that for market operations the OASIS EMIX and EnergyInterop and the IEC 62325 series specifications (available and coming) may apply. Market operations for DER are expected to be based on the protocols for Demand Response defined in IEC 62746 series..