Small-Signal Stability Analysis for Multi-Terminal LVDC Distribution Network Based on Distributed Secondary Control Strategy

Abstract

This paper presents a detailed and accurate small-signal analysis model for a four-terminal low-voltage direct current (LVDC) distribution network with distributed secondary control strategy. To tackle the contradiction between power sharing accuracy and average voltage recovery ability of voltage source converters (VSCs), a distributed secondary control strategy is adopted, which is based on average consensus algorithm and local voting protocol. Furthermore, to analyze the stability of LVDC distribution network based on the proposed distributed secondary control strategy, a detailed and accurate small-signal analysis model is formulated which is derived from various non-linear state-space sub-models. The time-domain simulation and electromagnetic simulation are carried out to verify the validity and accuracy of the proposed model. Based on this model, the influence rules of main eigenvalues are summarized with the variation of PI control and DC line parameters. Time-domain simulations conducted in PSCAD are used to validate the operational limits of the secondary controllers and DC line obtained from the small-signal stability analysis.

Emerging Technologies in Power Systems

“…In addition, due to the access to large-capacity RESs, interest in DC distribution system in power systems is increasing. In general, the DC power distribution system has a simple control method, a larger supply capacity, and lower line losses, as compared to the AC power distribution system [13]. However, as the application of LVDC systems with different characteristics of AC systems increases, fault analysis of LVDC systems is essential.…”

Consensus-Based Intelligent Distributed Secondary Control for Multiagent Islanded Microgrid

“…Distributed algorithms are used to implement the secondary controllers of the MG, as described in [14]. For voltage/frequency recovering [5], sharing of power [15], and compensation for imbalanced voltage, distributed cooperative control is primarily employed for secondary control [16]. In addition, the confict between reactive power sharing and voltage regulation is described in reference [17].…”