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28th European Photovoltaic Solar Energy Conference and Exhibition; 3616-3621, This paper discusses the possible contribution of PV-systems to frequency control. The influence on the conventional frequency control structure due to the transformation of the power system towards a converterdominated grid is presented. Based on this, an advanced frequency control concept is proposed and discussed.

Real-Time Digital Simulation (RTS) is a particular simulation method, which support the technology development process over the complete range from the early stage of simulations until the real testing of prototype units. This paper describes the functionality of Real-Time simulation during development process, here especially in the framework of an intelligent controlled on-load tap change (OLTC) transformer realising different voltage control strategies in a Low-Voltage (LV) network with high share of distributed energy resources (DER). For this purpose a comprehensive real electrical environment, due to a later field test, will be simulated using different Real-Time Simulation methods. The hardware of network elements which can be developed in parallel to the necessary control algorithms can be modelled in a first approach within the simulation environment. Afterwards the real hardware components can be integrated easily into this environment (RTS). For real environment testing, the closed-loop process is used (Hardware-in-the-Loop). In this paper several methods are investigated to build a stable and accurate power hardware simulation (Power Hardware-in-the-Loop).

27th European Photovoltaic Solar Energy Conference and Exhibition; 4076-4082, This paper describes solutions for voltage control in low-voltage distribution networks with a high penetration of decentralized feed-in systems. Electric equipment such as controllable distribution transformers with on-load tap changer (OLTC), reactive-power capable PV inverters and decentralized line voltage controllers were included in the study. After a short description of the issue of voltage control in distribution networks, we will continue with a description of the proposed solutions including the electric equipment and selected system concepts, as well as their advantages and disadvantages. In conclusion, a model of an existing low-voltage network is used to compare the concepts taking into account the potential increases in hosting capacity, losses caused by limiting active power, and the required reactive power that needs to be provided.

The new German BDEW MV guideline demands static and dynamic functionalities from distributed energy resource (DER) units in order to support network operation and stability. Initial indications show that, in general, photovoltaic (PV) inverters are able to fulfil both the static and the dynamic requirements. Besides the new requirements of the guideline, an extensive certification process for DER units and plants has also been introduced. During initial certification processes, a significant need for PV-specific test procedures and test equipment has been determined. This article describes the developments within this area from the perspective of a measurement institute.

26th European Photovoltaic Solar Energy Conference and Exhibition; 3223-3228, The new German BDEW MV guideline demands static and dynamic functionalities from distributed energy resource (DER) units in order to support network operation and stability. Initial indications show that, in general, photovoltaic (PV) inverters are able to fulfil both the static and the dynamic requirements. Besides the new requirements of the guideline, an extensive certification process for DER units and plants has also been introduced. During initial certification processes, a significant need for PV-specific test procedures and test equipment has been determined, since especially PV Systems have widely varying power ratings, ranging from a few kilowatts (e.g. string inverters) to several megawatts (e.g. central inverters). Therefore laboratory infrastructure used for the test, especially for dynamic requirements, has to be adopted with respect to the output power of the unit. This paper reflects the developments within this area from the perspective of a measurement institute.

23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 3096-3102, This paper introduces a Multifunctional PV-Inverter and its application for Power Quality improvement in electrical sub-networks. Measurement results point out the potential of this Multifunctional PVInverter concerning protection of sensitive loads against voltage variations, voltage dips and harmonics beside the conventional injection of PV-energy.