Electric Spring and Smart Load: Technology, System-Level Impact, and Opportunities

Abstract

Increasing use of renewable energy sources to combat climate change comes with the challenge of power imbalance and instability issues in emerging power grids. To mitigate power fluctuation arising from the intermittent nature of renewables, electric spring has been proposed as a fast demandside management technology. Since its original conceptualization in 2011, many versions and variants of electric springs have emerged and industrial evaluations have begun. This paper provides an update of existing electric spring topologies, their associated control methodologies, and studies from the device level to the power system level. Future trends of electric springs in large-scale infrastructures are also addressed.

Demand-Side Power Paradigm-Oriented Analysis of Reactive Electric Spring Stabilization Capabilities

“…where the variational quantities in (11) and (12) are taken with respect to the relevant nominal values. By (11), the range of ∆VG that can be stabilized depends on the achievable values of ∆VDL; by (12), the latter values depend on the components of the distribution line impedance and the achievable variations, sign included, of the active and reactive components of ̅ . For the demand-side power paradigm to be fulfilled, the sign of ∆INCL,a must be the same as ∆VG, i.e.…”

“…In [12], the two above-mentioned topologies are respectively referred to as ES-1 and ES-2. In addition to them, ESs with other active topologies have been proposed during the last years, like the back-to back (B2B) ES, where a backto-back converter is incorporated into the ES circuitry to avoid the use of any battery in the DC voltage link [13], and the RESintegrated ES, where a photovoltaic (PV) panel supplies ES [14].…”

Model Predictive Current Control of Multilevel Smart Load Based on MPUC7 Converter

“…As a result, recently, different versions of ES technology have been conceptualized for both dc and single/three-phase ac microgrids and power systems applications. Capacitor-based ES (ES1), battery-based ES (ES2), and back-to-back converter-based ES (ES3) are the three main generations of the single-phase AC electric spring [3]. Among these, ES1 is mainly focused on stabilizing the point of common coupling (PCC) voltage via direct reactive power compensation.…”

“…Moreover, it is investigated that ES1 can also mitigate frequency fluctuations through compensating active power indirectly [4]. Still, most of the reported works in this area are focused on ES2 and ES3 [3], [5]. Therefore, the need for more focused research on ES1 is clear.…”

“…On the other hand, regarding single-phase ES1 converter topologies, by far, two-level configurations have been mostly utilized [3]- [12], [14]- [16]. However, although these half/full-bridge-based ES1s require the least possible passive and active components in their structures, they have intrinsic topological disadvantages especially for higher power commercial and industrial applications.…”