Introduction

The VSYNC Project

In October 2007 the European project "VSYNC" started  with project co-ordinator Energy research Centre of the Netherlands (NL) and partners Technical University of Eindhoven (NL), Delft University of Technology (NL), Catholic University of Leuven (BE), Universitatea Politehnica Bucuresti (RO), FundaciĆ³n LABEIN, 3E NV (BE), UfE Umweltfreundliche Energieanlagen Handelsgesellschaft mbH (DE), Electrica SA (RO), and Continuon NV (NL).

The work in the VSYNC project is conducted with support of the European Commission, DG-TREN, Contract No. TREN/07/FP6EN/S07.72935/038584.

Problem definition

In electricity grids the frequency of the voltage is stabilized by a combination of the rotational inertia (rotating mass) of synchronous power generators in the grid and a control algorithm acting on the rotational speed of a number of major synchronous power generators. When in future small non-synchronous generation units replace a significant part of the synchronous power generation capacity, the total rotational inertia of the synchronous generators is decreased significantly. As a consequence the variation in the rotational speed of the synchronous generators due to changes in their net load will become much higher than at present. This causes large frequency variations that can end up in an unstable grid. Frequent blackouts in parts of the grid and social chaos in the areas concerned would be the result.

Solution

A way to stabilize the grid frequency is to add virtual rotational inertia to the distributed generators. A virtual inertia can be attained for any generator by adding a short-term energy store to it, combined with a suitable control mechanism for its power electronics converter. In this way a generator can behave like a "Virtual Synchronous Generator" (VSG) during short time intervals, and contribute to stabilization of the grid frequency.

Scope of the work

Demonstrations of the VSG concept are envisaged on the level of the individual owners of distributed generators, as well as on the level of the network operator for groups of many distributed generators.
As demonstrations have to be prepared very well in order to be successful, a significant part of the work is allocated to research on the laboratory development and testing of VSG concepts with different kinds of short-term storage. If successful, the project delivers prototypes of VSG's that are in the pre-market phase and can provide a cost effective solution to grid stability problems in areas where distributed generation is becoming significant.