Generalized short circuit ratio for multi-infeed LCC-HVDC systems

Abstract

The relationship between the short circuit ratio (SCR) and static voltage stability is analyzed in this paper. According to eigenvalue decomposition method, a novel concept named generalized short circuit ratio (gSCR) has been proposed for multi-infeed LCC-HVDC (MIDC) systems to mathematically measure the connected AC strength from the point view of voltage stability, which can overcome the rule-of-thumb basis of existing multi-infeed short circuit ratio (MISCR) concept. In gSCR, two indices, the critical gSCR (CgSCR) and the boundary gSCR (BgSCR) are developed to quantitatively evaluate if the connected AC system is strong or weak, in which CgSCR=2 and BgSCR=3 are two critical values for strength evaluation. Finally, numerical simulations are conducted to validate the effectiveness of the proposed gSCR concept.Index Terms--Static voltage stability, multi-infeed HVDC system, multi-infeed short circuit ratio, generalized short circuit ratio.

An on-line power/voltage stability index for multi-infeed HVDC systems

“…Except for the PVSI, there are three types of indices that are widely used for similar purpose: SCR-based indices [9][10][11][12][13][14], MPC-based indices [5,16] and VSF-based indices [6,17]. It is necessary to make a comparison and distinguish the advantages of the PVSI from the others.…”

“…Figure 9 shows some commonly used SCR-based indices. Among them, recently proposed tools such as EESCR and gSCR provide rigorous and analytical views of MIDC systems [10][11][12][13]. The EESCR is a rigorous extension of ESCR from single-infeed HVDC system to MIDC system, and the gSCR is an extension of SCR.…”

“…Reference [11] proposes a concept named generalized short circuit ratio (gSCR) to generalize SCR to MIDC system. The gSCR is mathematically deduced with the help of the Jacobian matrix of MIDC system, and shows better accuracy than conventional MISCR and MIESCR [12]. Reference [13] further elaborates on gSCR and illustrates the concept of critical gSCR and boundary gSCR, which prominently enriches gSCR's physical meaning.…”

“…Reference [13] further elaborates on gSCR and illustrates the concept of critical gSCR and boundary gSCR, which prominently enriches gSCR's physical meaning. Nevertheless, the SCR-based indices are used mainly for HVDC planning and selection for locations, as stated in [12][13][14][15]. Some advanced indices such as EESCR is capable for online application, while they require more data than conventional SCR [13].…”

Analysis and assessment standards of power stability of multi‐send HVDC systems

“…Both a multi‐send HVDC system [3–5] and a multi‐infeed HVDC system [6–9] involve multiple HVDC links. In a power system with multiple HVDC links, the effective short‐circuit ratio (ESCR) of a system with a single HVDC link can no longer be used to describe the strength of the system due to the interaction between different HVDC links.…”