The inertia response and primary frequency regulation capability of synchronous grids are declining owing to the increasing penetration of inverter-based resources. The fast frequency response(FFR) of inverter-based r...The inertia response and primary frequency regulation capability of synchronous grids are declining owing to the increasing penetration of inverter-based resources. The fast frequency response(FFR) of inverter-based resources is an important mitigation option for maintaining grid security under the conditions of low inertia and insufficient primary frequency response capability. However, the understanding and technical characteristics of the FFR of inverter-based resources are still unclear. Aiming at solving the aforementioned problems, this paper proposes a definition for FFR based on the impact mechanism of FFR on system frequency. The performance requirements of FFR are clarified. Then, the effects of FFR on system frequency characteristics are further analyzed based on steady-state frequency deviation, the initial rate of change of frequency, and the maximum transient frequency deviation. Finally, the system requirements for FFR and its application effects are verified by simulating an actual bulk power grid, providing technical support for subsequent engineering application.展开更多
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 fr...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.展开更多
A frequency following response(FFR) of speech auditory brainstem response(speech-ABR) elicited by the speech syllable/da/contains three distinct waves named as D, E and F, corresponding to the structure of the stimulu...A frequency following response(FFR) of speech auditory brainstem response(speech-ABR) elicited by the speech syllable/da/contains three distinct waves named as D, E and F, corresponding to the structure of the stimulus sound. The detection and characterization of FFRs are critical in the study and application of speech-ABRs. Conventional methods detect the latencies of the waves in time domain by measuring the maximal amplitudes of the waveform in the preset windows, which suffers the problem of low quality of FFR waves. In this paper, we defined an instantaneous energy(IE) spectrum based on empirical mode decomposition(EMD)method(EMD-IE method) to detect FFR and measured the latencies of the waves. The results reveal that the FFRs are mostly evident on the second layer of the IE spectra,which would benefit the detection and measurement of the FFRs in clinic.展开更多
The improvement of pitch perception is a hot spot in cochlear implant algorithm research. In order to provide objective and effective guidance for the algorithm research, psychoacoustic method and brainstem frequency ...The improvement of pitch perception is a hot spot in cochlear implant algorithm research. In order to provide objective and effective guidance for the algorithm research, psychoacoustic method and brainstem frequency following response(FFR)were studied in this paper to assess the ability of pitch perception among young people who exhibited the same normal hearing sensitivity. Eleven Chinese college students participated in both the psychoacoustic experiment and FFR experiment. Using pure tone as the stimulus, psychoacoustic frequency difference limen(FDL) and FFR neural pitch strength were measured. Both of them were used as parameters for evaluating pitch perception ability. FFR pitch strengths were extracted by three different methods which were autocorrelation, chirp z-transform and spectrogram. FFR pitch strengths correlated to a certain extent with FDL results and the FFR pitch strength by autocorrelation showed the highest degree of correlation. The results imply that in the same normal hearing population, features extracted from FFR signal can represent pitch perception ability of subjects. FFR features can be expected to become objective and effective parameters for assessing cochlear implant algorithms.展开更多
锁相是指系统的响应与周期性刺激的特定相位同步的物理现象.听觉神经的锁相对揭示人的听觉认知基本的神经机理及改善听觉感知有重要意义.然而,现有研究主要集中于心理物理方法和幅度谱分析,不能有效区分包络响应和时域细节结构响应,不...锁相是指系统的响应与周期性刺激的特定相位同步的物理现象.听觉神经的锁相对揭示人的听觉认知基本的神经机理及改善听觉感知有重要意义.然而,现有研究主要集中于心理物理方法和幅度谱分析,不能有效区分包络响应和时域细节结构响应,不能直观反映神经锁相.本文主要利用拔靴法和离散傅里叶变换,提出了基于样本熵的时域细节结构频率跟随响应(temporal-fine-structure-related frequency following response,FFR_T)的神经锁相值(phase locking value,PLV)计算方法,用于分析神经物理实验数据.两个脑电实验结果表明:FFR_T的PLV样本熵显著大于包络相关频率跟随响应(envelope-related frequency following response,FFR_E)的PLV,且二者正交独立,新方法能有效地分别反映听觉系统对包络和时间细节结构的锁相机理;基频处的响应主要来源于FFR_E的锁相;基频处,不可分辨谐波成分包络的锁相能力优于对可分辨谐波;基频缺失时,畸变产物是不同的听觉神经通路的FFR_E的混合;谐波处,FFR_E集中于低频,FFR_T则集中于中、高频;听觉神经元锁相能力与声源的频率可分辨性相关.FFR_T的PLV方法克服了现有FFR分析的局限性,可用于深入研究听觉神经机理.展开更多
基金supported by National Science Foundation of China(51477091)。
文摘The inertia response and primary frequency regulation capability of synchronous grids are declining owing to the increasing penetration of inverter-based resources. The fast frequency response(FFR) of inverter-based resources is an important mitigation option for maintaining grid security under the conditions of low inertia and insufficient primary frequency response capability. However, the understanding and technical characteristics of the FFR of inverter-based resources are still unclear. Aiming at solving the aforementioned problems, this paper proposes a definition for FFR based on the impact mechanism of FFR on system frequency. The performance requirements of FFR are clarified. Then, the effects of FFR on system frequency characteristics are further analyzed based on steady-state frequency deviation, the initial rate of change of frequency, and the maximum transient frequency deviation. Finally, the system requirements for FFR and its application effects are verified by simulating an actual bulk power grid, providing technical support for subsequent engineering application.
文摘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.
基金National Natural Science Foundation of Chinagrant number:F61172033
文摘A frequency following response(FFR) of speech auditory brainstem response(speech-ABR) elicited by the speech syllable/da/contains three distinct waves named as D, E and F, corresponding to the structure of the stimulus sound. The detection and characterization of FFRs are critical in the study and application of speech-ABRs. Conventional methods detect the latencies of the waves in time domain by measuring the maximal amplitudes of the waveform in the preset windows, which suffers the problem of low quality of FFR waves. In this paper, we defined an instantaneous energy(IE) spectrum based on empirical mode decomposition(EMD)method(EMD-IE method) to detect FFR and measured the latencies of the waves. The results reveal that the FFRs are mostly evident on the second layer of the IE spectra,which would benefit the detection and measurement of the FFRs in clinic.
基金National Natural Science Foundation of Chinagrant sponsor:60871083+1 种基金Beijing Natural Science Foundationgrant number:3082012
文摘The improvement of pitch perception is a hot spot in cochlear implant algorithm research. In order to provide objective and effective guidance for the algorithm research, psychoacoustic method and brainstem frequency following response(FFR)were studied in this paper to assess the ability of pitch perception among young people who exhibited the same normal hearing sensitivity. Eleven Chinese college students participated in both the psychoacoustic experiment and FFR experiment. Using pure tone as the stimulus, psychoacoustic frequency difference limen(FDL) and FFR neural pitch strength were measured. Both of them were used as parameters for evaluating pitch perception ability. FFR pitch strengths were extracted by three different methods which were autocorrelation, chirp z-transform and spectrogram. FFR pitch strengths correlated to a certain extent with FDL results and the FFR pitch strength by autocorrelation showed the highest degree of correlation. The results imply that in the same normal hearing population, features extracted from FFR signal can represent pitch perception ability of subjects. FFR features can be expected to become objective and effective parameters for assessing cochlear implant algorithms.
文摘锁相是指系统的响应与周期性刺激的特定相位同步的物理现象.听觉神经的锁相对揭示人的听觉认知基本的神经机理及改善听觉感知有重要意义.然而,现有研究主要集中于心理物理方法和幅度谱分析,不能有效区分包络响应和时域细节结构响应,不能直观反映神经锁相.本文主要利用拔靴法和离散傅里叶变换,提出了基于样本熵的时域细节结构频率跟随响应(temporal-fine-structure-related frequency following response,FFR_T)的神经锁相值(phase locking value,PLV)计算方法,用于分析神经物理实验数据.两个脑电实验结果表明:FFR_T的PLV样本熵显著大于包络相关频率跟随响应(envelope-related frequency following response,FFR_E)的PLV,且二者正交独立,新方法能有效地分别反映听觉系统对包络和时间细节结构的锁相机理;基频处的响应主要来源于FFR_E的锁相;基频处,不可分辨谐波成分包络的锁相能力优于对可分辨谐波;基频缺失时,畸变产物是不同的听觉神经通路的FFR_E的混合;谐波处,FFR_E集中于低频,FFR_T则集中于中、高频;听觉神经元锁相能力与声源的频率可分辨性相关.FFR_T的PLV方法克服了现有FFR分析的局限性,可用于深入研究听觉神经机理.
