Conference programme

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Thursday, 19 November 2015
14:30 - 16:00 Advanced design and control solutions for grid integration
Integrating wind power into the electricity market  
Onshore      Offshore    


Room: Montparnasse

Many new issues must be solved in order to integrate large amounts of wind power into energy supply systems. This session will consider how grid code compliance can affect wind power plant design and operation. Wind power plants must be able to tolerate short circuits on the grid, so testing of fault ride-through capabilities of turbines is required; and the design of circuit breakers for HVDC-connected wind farms is a particular issue. The session also considers harmonics caused by wind turbine inverters, and a method for modelling the effect of wind power plants containing multiple DFIG wind turbines is presented.

Learning objectives

​Delegates will be able to:

  • Understand grid code requirements for wind power integration
  • Recognise how wind pant can be designed and operated to comply with grid codes, and the effect on cost of energy
  • Understand new solutions for circuit breakers in HVDC-connected wind farms to deal with grid faults, and testing facilities for wind turbine fault ride-through capabilities
  • Appreciate methodologies for assessing harmonics caused by wind turbine inverters
  • See how symbolic computation can be used to simulate the effect of wind farms comprising DFIG wind turbines
Lead Session Chair:
Ervin Bossanyi, DNV GL - Strategic Research & Innovation, United Kingdom
Rainer Klosse WindGuard Certification GmbH, Germany
Co-authors:
Rainer Klosse (1) F
(1) WindGuard Certification GmbH, Varel, Germany

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Presenter's biography

Biographies are supplied directly by presenters at EWEA 2015 and are published here unedited

Mr. Rainer Klosse has been working in part of power quality measurements since 1995. Since 2011 he is managing director of Windguard Certification. Currently he is sector manager of electrical certification body according ISO EN 17065 and sector managing of electrical test lab according ISO EN 17025. Recommended as Power Plant Certifier by: German Federal Association of Energy and Water Management (BDEW) and Society for the Promotion of Wind Energy (FGW)(FNN)

Abstract

Voltage Vector Jump and High Voltage during Fault Ride Through Test

Introduction

During a Fault-Ride-Through event (FRT), in addition to the drop or rise of the voltage amplitude, the vector of the voltage jumps in pre- or post-direction. These vector jumps have sometimes a magnitude of more than 30 degrees. Additionally the stiffness of the grid (i.e. the short-circuit-power) changes during such events. The FRT-stability of a network is highly dependent on the capability of the production unit to handle these uncommon but sensitive grid situations. Grid models attempt to simulate FRT-events using models of the production unit which had been validated against measurements. In this context, how valid are these unit models, if a variation of these vector jumps of the voltage and a different set of impedance changes are not part of the prototype measurements?

Approach

Measurements are carried out at different types of production units where not only voltage amplitudes, but also jumps of the vector voltage as well as a change of the impedance occurred. The new auto transformer based FRT-test facility can create vector jumps of the voltage. Together with the spreading of the inductances at the high and low voltage sides of the transformer, different short-circuit-power changes, including the change of the impedance angle, can be simulated without the use of resistances. From the view of the unit under test, the conventional test facility - with length and short-circuit-impedances - can be simulated, as well as most relevant grid situations that provoke an unstable behavior of power units.

Main body of abstract

This presentation repeats the description of the new FRT-test facility. By using the two pole theory, a possible equivalence between the standard test facility with length and short-circuit impedance and the new FRT-test facility will be demonstrated. Results of idling tests and measurements at inverter systems, as well as at rotating machines under load at different grid impedances will be presented. A measurement of a group of inverters under the utilization of the new FRT-test facility will be shown. The benefit of a better model will be demonstrated by simulating relevant FRT-situations.

Conclusion

It can be observed that the high length impedance of conventional LVRT-test systems is part of the oscillation system between the stable grid point and the unit under test. By varying the length impedance with this new test facility, the dynamical stability of the power unit itself can be identified. The worst case for the power units, concerning voltage vector jumps, can be detected. Due to the possibility to trigger the FRT-event via IGBT-based switching units, it is possible to repeat each test at the same phase positions. All this leads to more accurate models.


Learning objectives
The measurements were carried out under utilization of a 10 kW FRT-test facility. The realization of a FRT-test facility capable to measure power units with powers larger than 3 MW is currently supported by the German Ministry of Economics.