Potential solutions to the challenges of low inertia power systems with a case study concerning synchronous condensers

Abstract

This paper will review the recent and on-going changes to the power system in Great Britain (GB). One of the main challenges resulting from these changes in generation mix is the assurance of frequency stability in a low inertia system, and the provision of adequate dynamic responses to frequency changes, while meeting the requirements of the energy trilemma. Specifically, the increase in penetration of non-synchronous generation increases the risk of undesired operation of protection devices and contributes to a shortage of dynamic immediate response to frequency changes.A range of potential solutions will be briefly reviewed in this paper including, demand side response (DSR), energy storage, synthetic inertia, and synchronous condensers. A case study concerned with evaluating the impact that synchronous compensation may have in a low inertia power system will be described in the paper. The paper will conclude with an outline of the avenues for further study towards addressing the challenge of frequency stability and system inertia in a future power system. Index Terms--Demand side response, energy storage, low inertia system, power system protection, RoCoF, synchronous compensation, synthetic inertia.

Battery Energy Storage Systems in the United Kingdom: A Review of Current State-of-the-Art and Future Applications

“…Inertia is an inherent property of power systems including conventional power plants, due to the kinetic energy generated and stored in the rotating parts of synchronous generators (SGs), which is released in case of disturbances to keep the frequency within safe operating limits [16]. On the other hand, power converters decouple the energy sources from the grid, and thus they do not provide inertial response [77].…”

“…Especially for the UK power system, which is not synchronised with the continental European power grid, and is expected to accommodate increasingly large amounts of RESs in the next decades, the decrease of power system inertia is becoming a concern for the transmission system operator (TSO) [78]. For example, the decrease in system inertia may result in undesirable operation of rate-of-change-of-frequency (ROCOF) relays, which are widely used in the UK, thus increasing the risk of loss of supply [77,79].…”

Challenges and Research Opportunities of Frequency Control in Low Inertia Systems

“…Recently, in order to deal with the impact of renewable resources on grid performance due to poor short-circuit power and low inertia support from converter-interfaced sources, SC is proposed as a potential solution for low inertia systems to support dynamic performance [31]. The benefit of SC in terms of inertial response support for frequency stability in renewable-based systems is investigated in [32,33].…”

Containing Loss Risk in a Low Inertia GB Power System

“…National Grid in [5] puts the cost of curtailing loss risk at £268m per annum by 2020, expected to increase year by year. Synchronous compensators are a potential solution that provides a range of system benefits [18]. It is plausible that implementation as the single solution to the issues of a very low (sub 75 GVAs) inertia GB power system would not be commercially viable, and indeed, the optimal solution may require a range of complimenting options.…”