Multivariable control with grid objectives of an HVDC link embedded in a large-scale AC grid

Abstract

International audienceThe HVDC links are increasingly used not only to interconnect asynchronous AC systems but are also embedded into a same meshed AC power system. Thanks to its speed and flexibility, the HVDC technology is able to provide transmission system advantages as transfer capacity enhancement and power flow control. In addition, studies have shown that the way of controlling the HVDC converters impacts the stability of the AC system. This can be particularly exploited to enhance the dynamic power system performances during transients. In this paper a robust multivariable control design for HVDC link converters is proposed. It is based on the coordination of the control actions of the HVDC converters and the use of a control model which takes into account the dynamics that mostly impact stability of the neighbor zone of the HVDC link. This new methodology was used to synthesize the controller for an actual grid 1000 MW HVDC link reinforcement project called ''Midi-Provence'' in the southern part of the French grid. The synthesis , implementation and validation processes are presented in detail. The new controller is tested in comparison with the standard vector control. A large-scale dynamic model of the whole European power system, currently used and updated by the European TSO's for the interconnection studies has been used with Eurostag simulation software. Ó 2015 Elsevier Ltd. All rights reserved. Introduction The HVDC link is a mean of transmission of electric power based on high power electronics. Thanks to its speed and flexibility, the HVDC technology is able to provide the transmission system advantages as transfer capacity enhancement and power flow control [1]. Initially, it was used in power systems to interconnect asyn-chronous AC systems. The ends of the HVDC link are electrically independent one from each other and this reduces significantly the propagation of perturbations between the two AC grids as it is the case of the England–France interconnection [2]. Nowadays, HVDC links are increasingly embedded into a same meshed AC system in order to enhance the grid's transmission capability and flexibility of the power system. In this context, the HVDC link co-exists with other AC system elements as for instance AC lines and generators. Several projects of insertion of this type of device in a meshed AC system are underway in Europe, as for instance France–Spain HVDC project [3], France–Italy interconnection and Midi-Provence HVDC project [4]. This latter is our case of study. In fact, a 1000 MW HVDC link will be inserted in France between the two areas Fos and Gaudière, in order to enhance capacity of power transmission and the stability of the Midi-Provence region. The need of such HVDC link is due to the fact that only one single 400 kV AC line interconnects the two areas (see Fig. 1). It was shown that the strategy used to control the HVDC converters can impact the stability of the system in which the link is embedded [5–12]. This conducted us develop a methodology which takes into accou...

Model Predictive Control of VSC-HVDC Embedded into AC Grid Subject to State and Control Constraints

“…Further research will be focused on improving post-fault response, and robustness against parameters uncertainties in order to apply the control to large-scale AC grids (e.g. the France-Spain grid [2]). This can be done by fuzzification (e.g.…”

“…Indeed, when inserted into AC grid, the HVDC regulations have an impact on the neighbouring AC dynamics, especially on transient stability. To optimize such impact, the control specification should be enlarged to AC grid transients [2]. In addition, controller design for state and actuator constrained VSC-HVDC systems is a challenging issue.…”

Exhaustive Modal Analysis of Large-Scale Interconnected Power Systems With High Power Electronics Penetration

“…Indeed, in the past, these modes, called inter-area modes, were quasi-exclusively due to large thermoelectric synchronous generators of which coherent groups of turbine-generator rotors oscillate one against other (see, e.g., [24]). Recently, other types of M. Kouki coupling modes have been put into evidence: in [1] and [2] coupling modes between classic synchronous generators but related to the electric parts (axes D or Q) of distant generators have been studied. They are thus not of inter-area nature.…”

“…In [17] oscillatory modes between converters of distant HVDCs were put into evidence and analyzed. Also, power converters (from HVDC or Power Parks Modules) may have important participation in inter-area modes and thus interact with synchronous generators [1], [7], [32]. These new types of modes are called electrical coupling modes in the sequel.…”

Eigencalculation of Coupling Modes in Large-Scale Interconnected Power Systems with High Power Electronics Penetration

“…However, power grids which contain power electronics may have coupling modes of different nature. For example, in [1] and [2] coupling modes between classic synchronous generators but not of inter-area nature were put into evidence. They are related to the electric parts (axes D or Q) of distant generators.…”