Controller to enable the enhanced frequency response services from a multi‐electrical energy storage system

Abstract

The increased adoption of renewable energy generation is reducing the inertial response of the Great Britain (GB) power system, which translates into larger frequency variations in both transient and pseudo-steady-state operation. To help mitigate this, National Grid (NG), the transmission system operator in GB, has designed a control scheme called Enhanced Frequency Response (EFR) specifically aimed at energy storage systems (ESSs). This paper proposes a control system that enables the provision of EFR services from a multi-electrical energy storage system (M-EESS) and at the same time allows the management of the state of charge (SOC) of each ESS. The proposed control system uses a Fuzzy Logic Controller (FLC) to maintain the SOC as near as possible to the desired SOC of each ESS while providing EFR. The performance of the proposed controller is validated in transient and steady-state domains. Simulation results highlight the benefits of managing the SOC of the energy storage assets with the proposed controller. These benefits include a reduced rate of change of frequency (ROCOF) and frequency nadir following a loss of generation as well as an increase in the service performance measure (SPM) which renders into increased economic benefits for the service provider.

Under-Frequency Load Shedding in Mongolia: Simulation Assessment Considering Inertia Scenarios

“…The assessment of the system frequency analysed is used as the main indicator for the evaluation of the UFLS [4]. As the MPS is not equipped with automatic generation controller (AGC), the system frequency is analysed in its more pure and classical primary response (see Fig.…”

Fast Frequency Response From Energy Storage Systems—A Review of Grid Standards, Projects and Technical Issues

“…It can be applied in converter interfaced energy resources, e.g. wind turbine, PV and ESS [48]- [54]. The active power output is in proportion to the rate-of-change-of-frequency by, in most cases, implementing a swing equation, thus can effectively mitigate ROCOF.…”

“… Continuous efforts on grid-scale ESS trials and projects to develop a mature service market, clarify the business model and identify key challenges. Recent research also throw emphasis on the design and control issues of ESS with multi-sources [48], [67], [68], techno-economic benefits [69][81] for these new services.…”

Synchronizing Stability Analysis and Region of Attraction Estimation of Grid-Feeding VSCs Using Sum-of-Squares Programming

“…Although this fast phase-tracking and frequency-following feature of the PLL is beneficial for the performance of the VSC power controls, it can result in an adverse effect on the transient frequency stability of the power system (Gonzalez-Longatt, 2016). Countermeasures can be taken in this regard; for instance, by augmenting ancillary controls on VSCs (Gonzalez-Longatt, 2016;Sanchez et al, 2019) so that they can contribute to the frequency response of the system. Aside from this issue, the PLL also poses adverse effects on the smallsignal stability of the VSC itself if not properly designed (Zhang et al, 2017a).…”