Analysis of compressor surge induced by converter low-voltage ride through and improvement measures

Abstract

[Objective] Centrifugal compressors encounter challenges in maintaining stable operation due to the occurrence of harmful surges, and the low-voltage ride through(LVRT) function of converters has been utilized to sustain continuous operation against power supply fuctuations. However, electric-driven centrifugal compressors frequently experience compressor surges during the converter LVRT process. Therefore, it is essential to analyze the surge causes and develop improvement measures for problem prevention. [Methods] This study focuses on electric-driven centrifugal compressors at the Turpan Interconnection Compressor Station of the West-East Gas Pipeline II.An investigation was carried out to analyze parameter changes, including compressor speed, pressure, fow, and anti-surge operating margin during the LVRT process. It was observed that the anti-surge control response was delayed as a result of rapid compressor speed drop during the converter LVRT process, leading to compressor surges. Subsequently, the sharp pressure and flow fluctuations following the surges rendered the anti-surge margin control ineffective, resulting in persistent compressor surges. Based on these findings, the following measures were devised to enhance anti-surge control:(1) incorporating additional measures for surge prevention during LVRT and LVRT state judgment, presetting trigger conditions for preemptively opening the anti-surge valve until a specified opening based on the compressor's operating margins and outlet pressure changes during the LVRT process;(2) implementing supplementary measures for compressor surge detection and protection, specifically by detecting noticeable changes in outlet pressure and variations in vibration that occur following compressor surges, and in response to any detected surge, promptly opening the anti-surge valve to eliminate the surge state. [Results] The implementation of the improvement measures effectively resolved surge-related issues during the LVRT process. By setting operating point margins and outlet pressure change thresholds, the frequency of preemptively opening the anti-surge valve was reduced, resulting in a swift restoration of normal compressor operation. [Conclusion] The research findings provide valuable approaches for effectively mitigating surge hazards and improving the operational stability of electric-driven centrifugal compressors. Therefore, they can serve as a reference for optimizing anti-surge control and improving surge detection in electric-driven centrifugal compressors.

Keywords

• compressor
• low-voltage ride through(lvrt)
• surge
• margin
• outlet pressure