EN 50549 Requirements for Parallel Connection of Production Facilities to Distribution Networks

The European standard “EN 50549 Parallel connection of production facilities to distribution networks” consists of the following subsections published under the same title:

• “EN 50549-1 Part 1: Connection to the low voltage (LV) distribution network - “Production facilities up to and including Type B” The standard describes the technical requirements for protection functions and operational capabilities for production facilities intended to operate in parallel with low voltage distribution networks.

For practical reasons this standard refers to the responsible party where the requirements must be defined by an actor other than the distribution system operator, e.g. distribution system operator, member state, regulatory authorities according to the legal framework. Usually the distribution system operator informs the manufacturer about these requirements.

This includes the European network codes and their national implementations as well as additional national regulations. In particular, additional national requirements may apply for connection to the distribution network and operation of the generating plant.

The requirements of this standard apply to production facilities, production modules, electrical machines and electronic equipment that meet all of the following conditions, regardless of the type of energy source and the presence of loads in the generator's network:

• Converting any energy source into AC electricity
• Production modules with a capacity of B or lower, according to Commission Regulation (EU) 2016/631, taking into account national practice for the decision on power limits between types A and B and types B and C.
• Connected to an AC low voltage distribution network and operated in parallel.

Production facilities connected to a medium distribution network fall within the scope of the EN 50549-2 standard.

Electrical energy storage systems that meet the above conditions are included. If generating modules of different types (A or B) are combined in a plant, different requirements apply to the different modules depending on the type of each module. Generating plants connected to the medium-voltage distribution network with a maximum apparent power of up to 150 kVA may comply with this standard as an alternative to the requirements of EN 50549-2, unless otherwise specified by the distribution system operator and the responsible party. A different threshold may be defined by the distribution system operator and the responsible party.

This standard recognizes the existence of specific technical requirements (e.g. network codes) of the distribution system operator or other responsible party in a Member State, which must be complied with. Excluded from the scope are:

• Selection and evaluation of the connection point
• Power system impact assessment, e.g. assessment of effects on power quality, local voltage rise, impact on operation of line protections
• Link assessment is a set of technical verifications performed as part of link planning.
• Islanding of generation facilities, both intentional and unintentional, where no part of the distribution network is involved
• Four-quadrant rectifier of drives that feeds the cutting energy back to the distribution network for a limited time without an internal source of primary energy
• Parallel operation time limited to 100 ms uninterruptible power supply
• Personnel safety requirements as already adequately met by current European standards
• Connecting a generating unit, module or plant to a DC grid

• The purpose of the standard “EN 50549-10 Part 10: Tests for the conformity assessment of generating units” is to provide technical guidance to evaluate the electrical characteristics of generating units and for tests on interface protection.

Mechanical issues are taken into account to the extent that they affect the electrical characteristics. The evaluation results are intended to be used to demonstrate the compliance of generating units with the technical requirements for grid connection. In this context, the evaluation results may also be used as part of a certification program.

Along with the type test results of the generating unit, all additional elements for connection to the grid (e.g. transformer, cabling, multiple units) are taken into account in the assessment of the final installation of a generating plant.

The requirements to be evaluated are covered in the following standardization documents:

• EN 50549-1 Requirements for generating plants to be connected in parallel to distribution networks - Part 1: Connection to the low voltage (LV) distribution network - Generating plants up to and including Type B”
• EN 50549-2 1 Requirements for generation facilities to be connected in parallel to distribution networks - Part 2: Connection to the medium distribution (MV) distribution network - Type B and above generation facilities

If the grid connection requirements are addressed in other documents or for other types of production modules for which no specific test procedure is provided, the test methods of this standard may be used, if applicable. This standard provides assessment criteria for the conformity assessment of production units in accordance with the above-mentioned standardization documents based on type tests. However, some requirements may be applicable at the production site level. Assessment of conformity with these site requirements is beyond the scope of this document. However, this standard may be used to demonstrate the capabilities of a production unit to be used in a plant.

As a result, it is possible that the conformity assessment of a production unit does not cover all aspects of the standardization documents mentioned above, as is usually the case when a requirement is assessed at the facility level. Therefore, the conformity assessment report clearly states which clauses of this standard are covered and which clauses are not. This standard recognizes the existence of specific technical test requirements in the various member states that must be complied with.

Our organization, which has been trying to support businesses from every sector with its testing, measurement, analysis and evaluation studies carried out in a wide range for years, has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. In this context, testing services in accordance with the "EN 50549 Parallel connection of production facilities to distribution networks" standard are also provided to businesses.