Research on Fault Analysis and Remote Fault Diagnosis Technology of New Large Capacity Synchronous Condenser

Abstract

Synchronous condensers offer significant benefits in large reactive power capacity and strong voltage support ability, which can effectively solve prominent problems such as commutation failure and voltage drop of ultra-high voltage DC converters. They are increasingly widely used in power grids. However, the large-capacity condenser has a large volume and complex structure and is prone to faults, which urgently requires research on fault feature analysis and diagnosis technology. This article analyzes the features of large-capacity synchronous condensers and their engineering advantages, such as increasing the short-circuit ratio of the receiving power grid, improving the transmission limit power, working in a forced excitation state for voltage support in the event of a commutation failure at the UHVDC receiving end, absorbing excess reactive power to suppress sudden voltage rise during DC blocking, and providing dynamically adjustable reactive power support for the AC power grid through flexible switching of late or leading phase states. This article provides common faults, such as mass imbalance, misalignment, friction, oil film oscillation, etc. At the same time, the fault characteristics are analyzed using computer simulation analysis, laboratory simulation analysis, and on-site measurement testing methods. A standard fault diagnosis method for synchronous condensers is proposed on this basis, utilizing fault pattern recognition and credibility evaluation. By establishing a library of fault models for the synchronous condenser and employing time-domain and frequency-domain signal analysis techniques, the credibility and nature of the fault are determined by calculating the instantaneous values and rate of change of the sampled signal using eigenvalues. Through the comparison and analysis of pertinent standards and historical data, the severity of the fault is ascertained, along with the trend and severity of the problematic synchronous condenser. The findings of this study have additionally advanced the progress of fault diagnosis technology for synchronous condensers with large capacities.