Abstract
As Distributed Generation (DG) is increasingly integrated into the networks, intermittency issues of some types of DG (such as wind energy) will potentially increase network operating costs or decrease network security. Concern regarding these effects has grown among Network Operators and in order to avoid them, new or updated wind parks are required to provide ancillary services to the network. These ancillary services include the fault ride-through capability and mainly those wind parks connected to a collector switching or distribution substation are asked to provide this service. Although some wind parks can already supply fault ridethrough capability to the network, most of them are still largely unable to do so due to the current DG protection scheme. This work concentrates on the development and assessment of new settings for the wind park protection scheme by closed-loop test in real time. This aims to allow wind parks to provide fault ride-through capability to the distribution network. A distribution network with a DFIG based wind turbine with ride-through-fault capability was modelled on the RTDS Simulator. The protective relay settings were then implemented into a commercial numerical programmable relay to be assessed by closed-loop real time test. Conclusions of the protective relay with the fault ridethrough requirement are presented and discussed.

Abstract
Using power-hardware-in-the-loop is a solution for testing the behavior of devices on an emulated grid, with greater flexibility and avoiding the introduction of disturbances or critical operating conditions in the utility grid. This paper highlights the implementation of such a setup, its challenges and the solutions to cope with its limitations. The emulated grid is then used for the experimental validation of a 10kVA converter, regarding fault-ride-through, dynamic reactive current support and frequency and voltage based droop control, leading to the identification of design improvement recommendations.

Abstract

Abstract
This paper proposes a near to real-time local market to provide reactive power to the transmission system operator (TSO), using the resources connected to a distribution grid managed by a distribution system operator (DSO). The TSO publishes a requested reactive power profile at the TSO-DSO interface for each time-interval of the next delivery period, so that market agents (managing resources of the distribution grid) can prepare and send their bids accordingly. DSO resources are the first to be mobilized, and the remaining residual reactive power is supplied by the reactive power flexibility offered in the local reactive market. Complex bids (with non-curtailability conditions) are supported to provide flexible ways of bidding fewer flexible assets (such as capacitor banks). An alternating current (AC) optimal power flow (OPF) is used to clear the bids by maximizing the social welfare to supply the TSO required reactive power profile, subject to the DSO grid constraints. A rolling window mechanism allows a continuous dispatching of reactive power, and the possibility of adapting assigned schedules to real time constraints. A simplified TSO-DSO cost assignment of the flexible reactive power used is proposed to share for settlement purposes.

Abstract
EU-SysFlex H2020 project aims at developing and testing innovative tools for the integration of high levels (above 50%) of renewable energy sources (RES) in the pan-European Electricity system. Those high levels of RES will increase the need for new sources of flexibility to support the system services, since there will be a decreasing number of conventional power plants connected to the grid, traditionally the main providers of these services. In this context, this study describes the Flexibility Hub (FlexHub) concept, part of the EU-SysFlex Portuguese demonstrator, consisting of a platform of tools managed by the distribution system operator to facilitate market-based flexibility provision to the transmission system operator (TSO) using resources connected to the distribution system. The FlexHub includes the provision of active power flexibility to the TSO (with an extended restoration reserve market concept), an essential tool to help the TSO balancing the grid, being a replicable concept that will become increasingly relevant in a future with a high share of decentralised assets connected to the distribution grids.

Abstract
The study at hand describes the state of the art regulatory framework for managing the distribution system operator (DSO)/transmission system operator (TSO) interface including information about the available flexibility data and access rights of the different grid operators. It describes a possible future procedure to manage this interface using software tools to support this coordination performing grid analysis and providing active as well as reactive power flexibility information at several TSO–DSO interconnection points. The proposed study gives a short overview of two optimisation approaches/software tools with different application functionalities, developed and adapted to meet the demands coming up with such tasks, performed within the European project ‘EU-SysFlex’. Both tools contribute to the objective of optimising available flexibility resources connected to meshed distribution grids with multiple grid connection points to the transmission grid. The investigations/calculations are performed using a real existing high-voltage grid of MITNETZ STROM. Using the outputs, provided by both tools, the demonstrator aims at providing beneficiary results for the discussion of how to evolve the regulatory framework. The functionality of the developed algorithms of both optimisation tools is evaluated and investigated by means of a live field test.