Technical

This brief presents key technical, interconnection and regulatory measures that should be considered to enable a smooth integration of renewable-based DG with high modularity and widespread installation in the distribution grid, such as PV and wind power plants.
Authors:
Leonard Hülsmann, Thomas Ackermann and Jan-David Schmidt

NRS097-2-3 (2023): This specification clarifies conditions under which small scale embedded generators (<1MW) may connect to distribution feeders without negative network impact, and thus not require impact studies. Application of the specification speeds up connection approvals significantly (NRS Association).

(SAMPLE) VDE -AR-N 4105 (2011) – Technical minimum requirements for the connection to and parallel operation with low-voltage distribution networks. German standard summarising essential aspects to be taken in to account to ensure safe and reliable network operation.

(Powerpoint) Provides an overview of the IEEE 1547-2018 Standard.

This standard:

Specifies functional requirements for all Distributed Energy Resources (DERs) connected to typical primary or secondary distribution voltage levels.  It applies regardless of type and size—synchronous, induction, and inverter-based resources of any size.

Gives precedence to synchronous generator design standards for DERs with synchronous generator units rated 10 MVA and greater.

Does not apply to resources directly connected to the bulk power system.

NRS097-2-1 2017 (Ed2.1 revised July 2020): This section of NRS 097 series aims to be technology neutral and focuses on the requirements at the interface between the embedded generator and the utility, although it is expected that the specification will mainly apply to photovoltaic grid connected systems interfaced through static power converter technology. Static power converters are also utilized to convert for example, wind power, micro-hydro power, pico hydro power, battery storage energy and fuel cells to grid compatible electricity.  This specification covers aspects of the Grid Code relevant to small-scale (up to 1MVA) embedded generators, including power quality and safety concerns. (NRS Association)

(Note: Superseded by 2018 version) This standard focuses on the technical specifications for, and testing of, the interconnection itself.  It provides requirements relevant to the performance, operation, testing, safety considerations, and maintenance of the interconnection. It includes general requirements, response to abnormal conditions, power quality, islanding, and test specifications and requirements for design, production, installation evaluation, commissioning, and periodic tests. The stated requirements are universally needed for interconnection of distributed resources (DR), including synchronous machines, induction machines, or power inverters/converters and will be sufficient for most installations. The criteria and requirements are applicable to all DR technologies, with aggregate capacity of 10 MVA or less at the point of common coupling, interconnected to electric power systems at typical primary and/or secondary distribution voltages (Institute of Electrical and Electronics Engineers).

This Regulation (EU 2016/631) establishes a network code which lays down the requirements for grid connection of power-generating facilities of any size, namely synchronous power-generating modules, power park modules and offshore power park modules, to the interconnected system. It, therefore, helps to ensure fair conditions of competition in the internal electricity market, to ensure system security and the integration of renewable electricity sources, and to facilitate Union-wide trade in electricity. (European Commission)

Explores Embedded Generation (or Distributed Generation) tariffs amongst different municipal electricity distributors and the impact on utility revenue. Principles to ensure cost recovery/revenue neutrality are covered, ephasizing the importance of moving from purely volumetric tariffs for DGfixed charges to recover fixed costs. revenue impact amongst different distributors is illustrated graphically (Sustainable Energy Africa, AMEU Convention)