Plant operators

Plant certification is a project-specific evaluation as to whether the generation plant, including all components, complies with the requirements for operation in the network at a given network connection point. The evaluation depends on the network conditions and must be harmonised with the requirements of the relevant network operator. In Germany, plant certification in the medium-voltage range is obligatory starting at a connected capacity of 1 MVA or as from a connection distance of more than 2 km. The network operator may also request a plant certificate when a large number of individual units are involved. The network operator states the requirements for the corresponding network connection point in a so-called "Network Operator Questionnaire"; compliance must be demonstrated during the certification process.

A plant certificate is obligatory both for new plants and for expanded plants or mixed plants (new or existing plants as well as mixed sources of energy, such as PV and cogeneration plants).

• Certification of generation plants with cogeneration plants, internal combustion engines, photovoltaic inverters and/or wind turbines
• Issuance of the declaration of conformity required for the plant certification, including a plant inspection
• Measurement of the generation plants if limits are exceeded, e.g. in case of harmonics
• Calculation of the feed-in related losses of revenue under a particular mode of active and reactive power operation
• Evaluation of the dimensioning of the operating equipment of a plant (short-circuit rating and continuous loading) and compensation plants (provision of reactive power)
• Review of the technical feasibility (concept review)
• Evaluation of the shut-down of generation plants in case of network disturbances (generation plant monitoring)
• Expert opinions and reports in the area of network connections

• maximum active power
• active power increase
• maximum active and reactive power diagram
• system perturbations (harmonics, flicker)

• monitoring of network voltage, frequency and reactive power consumption
• low-voltage ride-through; LVRT

• reduction in active power in case of over frequency
• set values for active and reactive power
• voltage or active power dependent reactive power

• Dimensioning of the operating equipment within the plant (switching systems, transformers possibly including step switches, cables)
• Protection concept in cases of faults on the network or in the plant
• Parametering of generation units, including of the certified software versions
• Fulfilment of the conditions from the unit certification
• Plant regulation and control concept (park control)