Hi-Tech Corporation

TD Guard Intelligent Sensor is an on-line CONTINUOUS Capacitance and tan-δ monitoring system for transformer bushings. TD Guard Intelligent Sensor is the first and only instrument on the market providing absolute Tan-δ measurement in on-line permanent monitoring of transformer bushings, granting the best level of diagnostic leverage and reliability. Sensitivity better than 10-4.

• First instrument on the market measuring absolute Tan-δ values in on-line permanent monitoring
• Innovative instrument for Capacitance, Tan-δ and Δtan-δ recording, storage & processing
• Zero drifts, innovative design for high thermal stability levels without drifts
• Fast response and accuracy

TD Guard Intelligent Sensor consists of a microprocessor-controlled unit supporting sophisticated sensors and conditioning front end. Fiber optic interfaces allow data download by a standard PC or a server able to record values of Δtan-δ (relative measure) and Capacitance and threshold setting.

TD Guard has the capability to present two alarm levels, according to a traffic-light approach, using the dedicated LED front lights or activating external alarms media by dry contact interface.
False alarms are avoided through advanced signal processing and field-proven algorithms able to eliminate the effect of noise or other environmental conditions that could lead to wrong diagnosis and inappropriate corrective actions.

TD Guard implements transformer bushing’s on-line monitoring through Capacitance and relative Δtan-δ measurement. Smart sensing algorithms are applied to obtain fast response and accuracy.

This intelligent sensor is designed to be used with TECHIMP PD analyzer, as the PDCheck unit and Techimp DGA-IS, providing Global diagnostic coverage and, thus, superior failure prevention. It may also be used as a stand alone device to get basic alarms on programmable threshold levels.