Initialisation of a hybrid AC/DC power system for harmonic stability analysis using a power flow formulation

Abstract

This study presents the initialisation of a hybrid alternating current/direct current (AC/DC) power system to determine the operation point around which the system is linearised as a starting point for an electromagnetic or harmonic stability analysis. To this end, each AC or DC power system component is modelled in the Fourier transform domain and further adjusted to a simplified representation compatible with a power flow formulation. The study also presents how voltage source converter (VSC) high‐voltage DC‐based systems can be analysed when the different VSC controls are applied. The result of the power flow solution is then used for the power converters’ initialisation.

Generalized impedance-based AC/DC power system modeling for harmonic stability analysis

“…In this work the power flow is solved using the PowerModelsACDC package written in Julia [29]. Since the determination of the system's operating point corresponds to the problem of finding the steady-state equilibrium [30], the power flow solution can be efficiently used as the system's operating point at which linearization is performed.…”

“…Using values for the AC and DC voltages and powers, the converter's operating point is estimated by solving a set of algebraic equations to obtain the steady-state operating point of the converter [29]. The reference values for the operating point of the converter are determined as:…”

“…In this work, the reference values for the AC power and DC voltage are obtained using AC/DC power flow Julia package named PowerModelsACDC.jl. The complete approach and setup is described in [29].…”

“…Gen 2 consumes the same amount of active power, supplies no reactive power, and has a balanced AC voltage, so P = −500 MW and Q = 0 MVA. The results obtained from the power flow solution [29] are presented in Table 2. To clearly demonstrate the reason behind explicitly considering the crosscoupling admittances of the MMC -both the AC-side cross-coupling admittances Y dq and Y qd and the AC/DC coupling admittances such as Y d,dc -the cross-coupling admittances are depicted in Figs.…”

Adaptive Control of HVDC Links for Frequency Stability Enhancement in Low-Inertia Systems

“…This model appears to be suitable for both electromagnetic transient (EMT) and spectral simulation. Furthermore, it can be incorporated into a power flow simulator with the generalization of inner controlling loops [29]. One important fact is the model's suitability to implement various controlling methods [30].…”