INTELLIGENT DIAGNOSTIC DEVICE Online Monitoring for Bushings and Current Transformers Bushings can fail slowly, giving you time to plan for replacement; they can also fail rapidly, leaving little time to act. With intelligent monitoring from Doble Engineering Company you can proactively manage risk in both situations and plan for replacements. With an embedded Expert System, Doble’s Intelligent Diagnostic Devices (IDDs) detect abnormalities in the bushing insulation and issue appropriate alerts. Benefits • Save costly equipment by quickly reacting to rapid deterioration warnings • Identify problem bushings and diagnose the severity of the situation • Plan for bushing replacements in a proactive, risk management approach Key Features • Bushing current waveforms captured • Measure leakage current magnitude and relative phase angles • Scalable device can monitor up to 12 bushings • Links to dissolved gas analysis & moisture devices such as the Delphi & DOMINO • Intelligent Expert System learns what is normal for your individual bushings • Displays alerts locally and remotely • Responds to subtle changes that may not be noticed by simple limit files • Optional armored cables & junction boxes for optimal performance in harsh environments Bushings Saved Bushings can fail gracefully or rapidly. The IDD is designed to detect both types of failures, giving you the time you need to act to save the bushings. IDD: Applying Doble Expertise The IDD Expert System identifies variation in the raw data leakage current and phase angle values but also applies to calculated C1 capacitance and Power Factor of the monitored bushings. The IDD Expert System will then provide notification alerts and alarms based on comparisons between the offline and calculated online data. Graceful Failure This chart shows a deteriorating power factor measured using an IDD over several weeks. Offline testing confirmed the results and the subsequent teardown found damage and discoloration of foils. Rapid Failure This raw data shows a significant increase in leakage current: a 30% increase in two hours. Offline testing confirmed the power factor at three times its normal value. The teardown found punctured foils and deteriorated paper. In both situations the Doble IDD allowed bushings to be removed from service before possibly catastrophic failures.

Technical Specifications Input Measuring Range Sampling rate Isolation between phases Power Supply Surge withstand Ambient Operating Temp: -40° to 65° C Storage Temp: -40° to 85° C Humidity: 5% to 95% non-condensing The IDD follows Doble’s three C’s of bushing monitoring a Control the measurement & ensure validity of data a Understand the Context – operational & condition data & design specific information a Draw appropriate Conclusions With the IDD, you can look at the raw data, which is often critical to understanding the root cause of a problem. The IDD lets you look at the raw waveforms....