Cooperative frequency control with a multi-terminal high-voltage DC network

Abstract

a b s t r a c tWe consider frequency control in power systems made of several non-synchronous AC areas connected by a multi-terminal high-voltage direct current (HVDC) grid. We propose two HVDC control schemes to make the areas collectively react to power imbalances, so that individual areas can schedule smaller power reserves. The first scheme modifies the power injected by each area into the DC grid as a function of frequency deviations of neighboring AC areas. The second scheme changes the DC voltage of each converter as a function of its own area's frequency only, relying on the physical network to obtain a collective reaction. For both schemes, we prove convergence of the closed-loop system with heterogeneous AC areas.

Interaction between the voltage‐droop and the frequency‐droop control for multi‐terminal HVDC systems

“…This section illustrates the behaviour of a 5-terminal MTDC system similar to the one used in [11] that interconnects two offshore wind farms and three asynchronous AC grids after a disturbance. Simulations are run with the electromagnetic transients program EMTP-RV.…”

Control of multi-terminal HVDC networks towards wind power integration: A review

“…For instance, Dai et al [45] present a distributed control scheme to provide primary frequency support in non-synchronous AC networks connected by MT-HVDC grids. Further improvement to this scheme is presented in [46], in which cooperative control tools are used to enforce the frequencies of the AC grids to converge to a common value. Two control schemes are proposed.…”

“…in cases of frequency support. In this case, the frequency in the WPPs can be adjusted using distributed control schemes like those proposed in [46].…”

Control strategies for automatic generation control over MTDC grids

“…A MTDC grid is composed of a DC grid and N AC areas, each with a converter which serves as an interface for transferring power to and from the DC grid, as in ( Sarlette et al, 2012). Each AC area i, for i = 1, 2, .…”