Wide area and broadband measurement system for modern power grid

Abstract

With the development of distributed clean energy, HVDC and FACTS, power electronic equipments such as SVC/STATCOM, China's power grid has developed into a large-scale complex power grid. The problem of subsynchronous oscillation (SSO) has become more and more prominent in the modern power system, and many SSO events have happened in China. Furthermore, the possibility of the ultra synchronous oscillation(USO) caused by the power electronic devices is also possible theoretically, but none of the existing measurement systems can offer any useful information about it. In addition, the low frequency signal, such as the DC signal at HVDC substation, and the high frequency signal, such as harmonic and interharmonic component, are not measured in typical wide area measurement system(WAMS). This paper is to introduce a novel wide area and broadband measurement system (WABMS), which is composed of advanced phasor measurement units(PMU), communication network and control center. Besides the function of synchrophasor measurement, this system can also synchronously measure the DC, harmonic and interharmonic signal, record the original waveform continuously, and send the synchronized information to the control center. WABMS is able to monitor the broadband signal from 0Hz to 3000Hz, and can be used for state supervisor of fundamental frequency, harmonic and interharmonic component. Especially, for the prominent SSO problem, this system can detect the SSO event and identify the SSO source.