Synchronized Waveforms a Frontier of Data-Based Power System and Apparatus Monitoring, Protection and Control
Abstract : Voltage and current waveforms contain the most authentic and granular information on the behaviors of power systems. In recent years, it has become possible to synchronize waveform data measured from different locations. Thus largescale coordinated analyses of multiple waveforms over a wide area are within our reach. This development could unleash a set of new concepts, strategies, and tools for monitoring, protecting, and controlling power systems and apparatuses. This paper presents an in-depth review and analysis of the advancements in synchronized waveform data, including measurement devices, data characteristics, use cases, and comparisons with synchrophasor data. Based on the findings, five strategies are proposed to discover and develop synchronized waveform based applications over multiple application areas. The paper also presents three complementary measurement platforms and two data screening algorithms for application implementation. It further discusses committee activities and standard developments useful to explore the full potential of the data.
? In existing protection methods, a microgrid can cause many challenges in terms of the protection of blinding zones, false tripping of protective relays, decreasing fault levels, islanding, and auto-reclosers.
? The WT method is based on transformation from the time domain into the time-frequency domain.
? Fault location method uses two different ways based on the existing communication scheme, a single-ended method, and a double-ended method.
? A single end fault location scheme is also possible when the current and voltage transients are available at the relaying point.
? A set of traveling-time equations can be established for the TOAs according to the network topology.
? The location is solved using an optimization method, as this is an over-determined problem.
? In view that it is impossible to have SMUs at all substations, proposed to deploy (portable) SMUs at the site that experiences harmonic problems (Bus X) and at the suspected load (Load C).
? As a result, one can derive meaning from the system level instead of the individual monitor level.
? Sync-waves, therefore, have an edge to solve problems involving more than one location or one component.
• The system protection scheme has to be changed in the presence of a microgrid, so several protection schemes have been proposed to improve the protection system.
• Microgrids are classified into different types based on the DC/AC system, communication infrastructure, rotating synchronous machine or inverter-based distributed generation (DG), etc.
• The authors proposed an adaptive distance protection based on the information surrounding the protected line under different operating conditions.
• A discrete wavelet transform has been proposed for HIF detection along with frequency range and RMS conversion to implement a pattern recognition-based detection algorithm.
? Apparatus monitoring includes condition monitoring, performance monitoring, parameter estimation, protection and so on.
? Due to page limitation, this section will focus on the application of sync-wave data to apparatus health condition monitoring.
? Sync-waves can be very useful for power grid event analysis. Examples are postmortem investigation, forensic examination, performance/model verification, troubleshooting analysis, and design validation.
? On-demand streaming also includes data retrieving through automatic polling by the control center (for online monitoring applications). Therefore, efficient and seamless on-demand access to data is an important design consideration for a SWAMS.
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