Modeling, Experimental Validation, and Application of VARC HVDC Circuit Breakers

Abstract

This paper deals with the modelling, hardware results and model validation by measurements of a VSC assisted resonant current (VARC) dc circuit breaker (CB) and the application within a future network by simulation. The newly emerging VARC dc CB can be used as a solution for the protection of offshore multi-terminal HVDC (MTDC) grids. In this paper, the proposed VARC dc CB is modelled in detail in a PSCAD environment, by taking into account dielectric strength of the vacuum gap, high-frequency current quenching ability and parasitic components. The PSCAD-model is then verified by data from the testing of a 27 kV VARC dc CB prototype with maximum current interruption capability of 10 kA. Additionally, the initial transient interruption voltage and current slope at zero-crossing during the interruption are analyzed. With respect to scaling to a higher voltage level, three types of series connected modules are presented and the performances are compared. The performance of the series connected modules is simulated in a model of a 4-terminal HVDC grid. The obtained results validate the VARC dc CB as a promising solution for the dc fault isolation in MTDC grids. Index Terms-HVDC circuit breaker, VARC, PSCAD, circuit breaker performance, HVDC grid, transient analysis. I. INTRODUCTION HE integration of sustainable and renewable technologies is changing the existing transmission system [1]. Significant progress has been made toward the development of Voltage Source Converters (VSCs) in the last few years, which enable meshed HVDC grid to provide a promising This work has received funding from the European Commission under project 691714-PROMOTioN (Progress on Meshed HVDC Offshore Transmission Networks) through Horizon 2020 program."

HVDC Circuit Breakers–A Review

“…A variety of current injection breaker, with a different injection circuit was used on the +/-160 kV Nan'ao system in China [7] and Mitsubishi have tested a 16 kA breaker [21]. An active resonant injection circuit has also been proposed, [40], [41], [42], [43]. This principle is shown in Fig.…”

Short-Circuit Fault Current Calculation Method for the Multi-Terminal DC Grid Considering the DC Circuit Breaker

“…During the energy absorption procedure, the energy absorbed by the MOV is mainly from two aspects: the energy storage of the fault line equivalent inductor and the energy injected by the MMC converter [31]. When the fault loop resistance is ignored (only the metallic short circuit fault is considered), the expression of E ar is as follows:…”

Coordinative performance of HVDC circuit breakers in MTDC grids

“…4 shows the current and the voltage waveforms of the VARC DC CB and the mechanical DC CB during the interruption where I line is the current through the DC CB, I vi is the current through the vacuum interrupter (VI), I sa is the current through the energy absorption branch, and V vi is the voltage across the VI. L DC is chosen to limit the rising rate of the fault current with the value of 100 mH based on [14], the same L DC value is applied in both types of DC CBs. The detailed operation sequence for both circuit breaker topologies is explained as follows: Before the operation of the DC CB, the VSC energy storage capacitor (C DC ) is pre-charged by the charging circuit in VARC.…”

“…This paper investigates the coordinative performance by implementing two types of DC CBs in a four-terminal MTDC grid. The two DC interruption technologies are active injection mechanical DC CB [13], and VSC assisted resonant current (VARC) DC CB [14], respectively. It needs to point out that these two types of DC CBs implemented in the MTDC are only used to represent the mechanical DC CB and hybrid DC CB, and the comparison of interruption characteristics of these two CB topologies is not the objective of this paper.…”