Power grid disturbance analysis using frequency information at the distribution level

Abstract

Disturbance analysis is important to the study of the power transmission system because it facilitates the modeling, operation and planning of the system. Traditionally, disturbances are described as megawatt (MW) events, but the access to data is inefficient due to the slow installation and authorization process of the monitoring device. In this paper, we propose a novel approach to disturbance analysis conducted at the distribution level by exploiting the frequency recordings from Frequency Disturbance Recorders (FDRs) of the Frequency Monitoring Network (FNET/GridEye), based on the relationship between frequency change and the power loss of disturbances, which is linearly associated by the Frequency Response. We first analyze the real disturbance records (in megawatt) of North America from the year 1992 to 2009 and confirm the power law distribution; meanwhile we discover that small disturbances are log-normal distributed. Then based on the real records from 2011 to 2013 (EI), the disturbances in megawatt and the corresponding frequency change records are studied in parallel. We prove that the frequency change of disturbances and its megawatt records share similar power law distribution when the disturbances are large; the frequency change can be delineated by a log-normal distribution with its numerically approximated coefficient when the disturbances are small. These findings have enabled the analysis of disturbances as frequency changes monitored at the distribution level with much better resolution and significantly faster access of data.