Synchronverter-Based Emulation and Control of HVDC Transmission

Abstract

International audienceThis paper presents a new control strategy for High Voltage Direct Current (HVDC) transmission based on the synchronverter concept: the sending-end rectifier controls emulate a synchronous motor (SM), and the receiving end inverter emulates a synchronous generator (SG). The two converters connected with a DC line provide what is called a Synchronverter HVDC (SHVDC). The structure of the SHVDC is firstly analyzed. It is shown that the droop and voltage regulations included in the SHVDC structure are necessary and sufficient to well define the behavior of SHVDC. The standard parameters of the SG cannot be directly used for this structure. A specific tuning method of these parameters is proposed in order to satisfy the usual HVDC control requirements. The new tuning method is compared with the standard vector control in terms of local performances and fault critical clearing time (CCT) in the neighboring zone of the link. The test network is a 4 machine power system with parallel HVDC/AC transmission. The results indicate the contribution of the proposed controller to enhance the stability margin of the neighbour AC zone of the link

A Review on Grid-Connected Converter Control for Short-Circuit Power Provision Under Grid Unbalanced Faults

“…With current references (12) and (18), the instantaneous active and reactive output power can be finally represented by (16) and (15) respectively. It is worth noticing that a set of unbalanced current is injected to the grid and oscillations in double fundamental frequency are registered in reactive power.…”

“…The concept of synchronverter is introduced in [15], where the grid-connected VSC is controlled in a manner that resembles traditional synchronous generators, enabling converter the capabilities of load sharing and voltage regulation. Its application to HVDC transmission and wind farms has been reported in [16] and [17] respectively. This paper aims to review current control strategies of gridconnected VSC under unbalanced grid faults considering grid requirements and converter current limit, for the sake of studying the potential impact of future converter-based power systems on the transmission-side protective relays.…”

Modeling and Analysis of an LCC HVDC System Using DC Voltage Control to Improve Transient Response and Short-Term Power Transfer Capability

“…These maximum and minimum limits of the converter controller gains were determined based on previous studies [27]- [29], while ensuring the stabilized variation in Vdcr and Idci for the full operating range of the converters. In [27]- [29], HVDC systems were modelled using the rated DC voltage and power similar to those of the test HVDC system in this paper: i.e., Vdc_rated = 184 kV and Pdc_rated = 150 MW. Note that optimizing the converter controller gains is beyond the scope of this paper.…”

Self-synchronisation of wind farm in MMC-based HVDC system

“…However, these values could not be the optimized parameter and could not directly apply in the synchronverter based WECS. A specific tuning method based on the eigenvalue and participation factor analysis of the individual states is presented in [17]. The optimized parameters used in this work are D p = 102 and D q = 52696.…”