Electrical engineering design for battery storage and grid connection
Battery storage electrical design: system layout, sizing and grid calculations for safe, grid-supportive energy systems.
Precise electrical engineering design is the basis for the safe and efficient operation of modern energy systems. We support you from the concept phase to implementation: from system layout and sizing of the energy storage to grid calculations. The result is safe, efficient and grid-supportive solutions. To the grid, a battery storage system behaves like a generating plant or like a consumer, depending on its operating state; electrical design for battery storage must therefore cover charging from the grid as well as feed-in. Depending on the arrangement, the storage system is a stand-alone plant, shares the grid connection with a generating plant or belongs to an existing consumption plant, and each of these variants requires its own electrical concept.
Electrical design of the battery storage system ranges from internal cabling through grid export to the grid operator's point of feed-in. We calculate load flow, short circuit, loss optimisation and thermal sizing with modern methods, and the grid impacts show grid compatibility. The yardstick is set by the grid operators' technical requirements, which in Austria are laid down in the technical and organisational rules (TOR). They concern behaviour during frequency and voltage deviations, the provision of reactive power and grid protection. Plants must ride through short voltage dips, and in medium voltage reactive current is fed in to support the grid. Switching on is permitted only at permissible voltage and frequency, after which power may rise only in a limited ramp. If a storage system raises the short-circuit current above the rated value of existing equipment, countermeasures such as current limitation or reinforcement of the installation must be agreed. The grid decoupling protection disconnects the plant when limits are violated, and reactive power is controlled, as specified by the grid operator, via a fixed value or a voltage-dependent characteristic. Three-phase plants must be designed symmetrically.
For the grid connection of a battery storage system, the grid operator's connection concept records the connection point, maximum power, permissible grid impacts and the reactive power method. For electrical design, the following applies: the larger the connection capacity, the higher the connection point in the grid as a rule; large plants are typically connected at the substation. For larger plants, the grid operator first assesses the application and presents a grid concept and grid access agreement; building permit and electricity-law approval must then be demonstrated, and on commissioning it specifies the required evidence, tests and releases. Before construction and any substantial modification, agreement with the grid operator must be reached; whether a responsible plant manager is prescribed for the plant depends on the relevant regulations and the specific plant configuration. We coordinate early with our permitting department so that risks do not arise in the first place, and we support you in communication with the grid operator.
The starting point is often the load profile analysis for storage and grid, which clarifies the required storage capacity. Grid coordination runs through the grid concept. Which components are provided for this is covered by consulting and planning on equipment for battery storage and smart grid. This is followed by the detailed design for storage and grid.
