Coordinated Supervisory Control of Multi-Terminal HVDC Grids: A Model Predictive Control Approach

Abstract

Abstract-A coordinated supervisory control scheme for future multi-terminal High-Voltage Direct-Current (HVDC) grids is proposed. The purpose is to supervise the grid and take appropriate actions to ensure power balance and prevent or remove voltage or current limit violations. First, using DC current and voltage measurements, the power references of the various Voltage Sources Converters (VSC) are updated according to participation factors. Next, the setpoints of the converters are smoothly adjusted to track those power references, while avoiding or correcting limit violations. The latter function resorts to Model Predictive Control and a sensitivity model of the system. The efficiency of the proposed scheme has been tested through dynamic simulations of a five-terminal HVDC grid interconnecting two asynchronous AC areas and a wind farm.

Local control of AC/DC converters for frequency support between asynchronous AC areas

“…Its cooperation with the existing conventional secondary frequency control has been also demonstrated, showing that by keeping the controller active while secondary frequency regulation is acting, the pre-disturbance power transfer between the two AC areas can be restored, unless a DC voltage Future work includes further investigation of DC-side events, which could cause activation of frequency support in both systems at the same time, and the coordination with a centralized, slower MTDC grid control [15], aiming at monitoring the whole DC grid and coordinating the VSCs.…”

Decentralized model predictive control of voltage source converters for AC frequency containment

“…Furthermore, in case a DC voltage or frequency limit violation has been already observed, a progressive constraint tightening approach can be applied, as described in [30]. The controller operation for N c = 3 steps is illustrated in Fig.…”

Frequency Participation Factors

“…In [25], the authors propose a Model Predictive Control (MPC)-based coordinated control for multi-terminal HVDC grids to ensure power balance in the system while avoiding current and or voltage limit violations, in a time frame of seconds/few minutes. To this aim, [25] considers the concept of power participation factors (PPFs) to update the reference powers of the converters of the HVDC systems, being the summation of all PPFs equal to unity.…”

“…To this aim, [25] considers the concept of power participation factors (PPFs) to update the reference powers of the converters of the HVDC systems, being the summation of all PPFs equal to unity.…”

“…Therefore, FPFs cannot be chosen/modified for/by a controller or any other agent such as system operators. This is in contrast with the participation factors described in [25] and [26], as they are chosen based on the capability of each converter to reschedule their power flows, and on the result of an optimal control problem, respectively.…”