Lightweight CNN-Based Anomaly Detection for High Voltage Converter Modulators in the Spallation Neutron Source
基于轻量级CNN的散裂中子源高压转换器调制器异常检测
Alberto D. Cencillo, Leonardo Concepción, Julián Luengo, Isaac Triguero
AI总结 针对高压转换器调制器多通道信号异常检测,通过改变时间滤波与跨通道混合的顺序并引入自适应通道重加权,在公开数据集上达到AUC-PR 0.816和AUC-ROC 0.934,超越现有方法。
Comments 21 pages, 8 figures
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高功率脉冲转换器的非计划停机是大型加速器设施停机的主要原因。在散裂中子源(SNS)中,高压转换器调制器(HVCM)始终是丢失束流时间的第二大贡献者。每个HVCM脉冲通过跨电流、电压和磁通量的传感器通道记录,这些通道的相互交互编码了系统的运行状态。故障前兆在这些通道中并非均匀显现:根据故障类型,它们可能改变单个信号的时间结构,改变通道间的统计依赖性,或两者兼有。现有的深度学习方法通常使用标准卷积流水线处理多通道信号,该流水线从第一层开始就纠缠时间和跨通道操作,使得模型没有明确的机制来表示通道独立性或结构化的通道间交互。我们假设架构归纳偏差,特别是时间滤波和跨通道混合的顺序,在这类数据的检测性能中起着核心作用。为了验证这一点,我们改变了这两个操作的顺序,并检查每个脉冲的自适应通道重加权是否进一步提高灵敏度。在涵盖所有四个SNS子系统(RFQ、DTL、CCL、SCL)的公开HVCM数据集上评估,我们最好的变体实现了池化AUC-PR为0.816和AUC-ROC为0.934,在大多数子系统和六个故障家族中的五个上优于现有技术。消融实验识别出三个主导输入通道,并将每个故障家族的性能与前兆表现为单个通道的幅度偏移还是需要联合通道表示才能显现的更细微模式联系起来。
Unscheduled trips of high-power pulsed converters are a leading source of downtime at large accelerator facilities. At the Spallation Neutron Source (SNS), the High Voltage Converter Modulators (HVCMs) are consistently the second-largest contributor to lost beam time. Each HVCM pulse is recorded across sensor channels spanning currents, voltages, and magnetic fluxes, whose mutual interactions encode the operating state of the system. Fault precursors do not manifest uniformly across these channels: depending on fault type, they may alter the temporal structure of individual signals, change the statistical dependencies among channels, or both. Existing deep-learning approaches typically process multi-channel signals with standard convolutional pipelines that entangle temporal and cross-channel operations from the first layer, giving the model no explicit mechanism to represent channel independence or structured inter-channel interaction. We hypothesise that architectural inductive bias, specifically the ordering of temporal filtering and cross-channel mixing, plays a central role in detection performance on this class of data. To test this, we vary the order in which these two operations are applied, and examine whether per-pulse adaptive channel reweighting further improves sensitivity. Evaluated on the public HVCM dataset across all four SNS subsystems (RFQ, DTL, CCL, SCL), our best variant achieves a pooled AUC-PR of 0.816 and AUC-ROC of 0.934, outperforming the state of the art on most subsystems and five of the six fault families. Ablations identify three dominant input channels and link per-fault-family performance to whether precursors manifest as amplitude shifts in individual channels or as subtler patterns requiring joint channel representations to surface.