Reliability, Efficiency and Cost Trade-offs for Medium Voltage Distribution Network Expansion using Refurbished AC-DC Reconfigurable Links

Abstract

The role of MVDC links for distribution network expansion is important. The distribution network operators (DNOs) can maximize the power transfer capacity of existing grid infrastructure during (n-1) contingencies using reconfigurable parallel ac-dc architecture. In addition this concept involves a range of efficiency, reliability and economic trade-offs. The object of this paper is to present a discussion on the emerging choices involved in adopting a parallel ac-dc reconfigurable link architecture in designing future and flexible power grids.

Offline Reconfigurability Based Substation Converter Sizing for Hybrid AC–DC Distribution Links

“…2. Such an arrangement can be present in transmission and DNs as suggested in [31], [32]. Using ac and dc feeders, the number of conductors N ac and N dc can be strategically selected to operate as ac and dc links respectively.…”

“…The cross-sectional area (A con ) and operating temperature (T ac , T dc ) dependent per kilometer conductor resistances are r ac and r dc . In this study, A con of both ac and dc link are considered equal because the system is developed using the refurbishment strategy for a completely ac link system described in [32], [33]. However, the presented equations can be generically applied for any magnitude.…”

Modular Multilevel Converter Performance with Dynamic MVDC Distribution Link Voltage Rating

“…Furthermore, in [9], the concept of system reconfigurability is introduced to maintain capacity enhancement during (n-1) contingencies. Various choices and trade-offs in operational reliability, cost and efficiency are highlighted in [10]. In [11], the operational efficiency boundaries of parallel ac-dc reconfigurable link system are defined.…”

“…Herein, the average component is controlled to the dc link voltage (v d ) while the ripple component is determined from the total energy ripple ∆W Σ and imbalance energy ripple ∆W ∆ defined in (10) and (11) respectively, as per the theory presented in [20].…”

“…However, the energy ripple terms ∆W Σ and ∆W ∆ remain the same as (10) and 11respectively as they correspond to the actual power flow corresponding to the controlled dc link and ac quantities. Fig.…”