Risk Assessment of Post-Fault Temporary Overvoltage Using Generalized
Short-Circuit Ratio
Abstract
Temporary overvoltage (TOV) is becoming one challenge for the
integration of significant power electronics resources into a power
system. To assess the risk of TOV in a Multi-Infeed Power Electronic
System (MIPES), a worst-case estimation approach is proposed to assess
TOV risk. The paper starts with analyzing the mechanism of TOV, which
reveals that TOV is dominated by excessive reactive power resulting from
control lagging of converters. Then, the principle of approximating the
TOV for a Voltage Source Converter (VSC) connecting to an infinite bus
is introduced within the context of the RMS model. After that, a
methodology based on the concept of generalized short-circuit ratio for
overvoltage (gSCR-TOV) is introduced to quantify the risk of TOV in a
multi-bus system. The intent of this concept is to permit screening to
identify those nodes at greatest need for further EMT assessment. To
localize these nodes, a concept of weighted sensitivity matrix is
further proposed to pinpoint the bus subject to highest TOV in a MIPES.
Finally, case studies of EMT time-domain simulations are carried out and
verifies the effectiveness of the proposed methodologies.