Adaptive Under-Frequency Load Shedding

Under-frequency load shedding （UFLS） is used in the power industry to rescue systems facing extreme disturbances to avoid system collapse. Traditionally, many computations are repeated to seek the proper power system settings such that the UFLS provides the desired good performance for selected scenarios. An adaptive UFLS method based on the genetic algorithm was developed to automate the finding of optimal parameters to minimize the repetitive trial-error calculations. Simulations demonstrate that the method has better performance than previous schemes and reduces the time and effort of the repetitive simulations.

Contingency Reserve Evaluation for Fast Frequency Response of Multiple Battery Energy Storage Systems in a Large-scale Power Grid

Recently,the fast frequency response(FFR)service by large-scale battery energy storage systems(BESSs)has been successfully proved to arrest the frequency excursion during an unexpected power outage.However,adequate frequency response relies on proper evaluation of the contingency reserve of BESSs.The BESS FFR reserve is commonly managed under fixed contracts,ignoring various response characteristics of different BESSs and their coexisting interactions.This paper proposes a new methodology based on dynamic grid response and various BESS response characteristics to optimise the FFR reserves and prevent the frequency from breaching the under-frequency load shedding(UFLS)thresholds.The superiority of the proposed method is demonstrated to manage three large-scale BESSs operating simultaneously in an Australian power grid under high renewable penetration scenarios.Further,the proposed method can identify remaining battery power and energy reserve to be safely utilised for other grid services(e.g.,energy arbitrage).The results can provide valuable insights for integrating FFR into conventional ancillary services and techno-effective management of multiple BESSs.

Development approach of a programmable and open software package for power system frequency response calculation

Dynamic behaviour of frequency is crucial for power system operation and control.Several frequency response models have been proposed to reveal frequency dynamics from different aspects.A comprehensive software package incorporating major frequency response models is needed for analysis and control of power system frequency dynamics.In this paper,an approach for developing a programmable and open software package for frequency response studies is proposed.The framework of the package is extendable with reduced frequency response models.Essential models for frequency response study are included,e.g.,generator,load,and under-frequency load shedding(UFLS).The provided application program interfaces(APIs)enable simulation with high-level languages by calling dynamic link library and makes the package programmable.An advanced application module is developed for quantitative assessment of transient frequency deviation.APIs can also be used for model extension and secondary development.To demonstrate the usage of the package,several examples are illustrated to explain how to perform simulations with the package,and to perform advanced applications using scripting with the provided APIs.