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Sophisticated monitoring system for on-load tap-changers

Your benefits at a glance

  • Comprehensive monitoring system for MR on-load tap-changers
  • Online monitoring
  • Torque calculation of the on-load tap-changer
  • Condition-based maintenance reduces the product lifecycle costs of your on-load tap-changer
  • Increase the reliability of your transformer

Product description

With the online monitoring system TAPGUARD® 260, monitoring the current operating status of your MR tap changer could not be easier. The device determines the current operating parameters of the tap changer, such as load current, temperature, motor drive data, tap-change torque and contact position, during each tap change operation.
On the basis of this information, the TAPGUARD® 260 monitoring system evaluates the proper execution of every current tap-change operation online.

If a preset limit value is exceeded, the TAPGUARD® 260 blocks the motor drive and prevents extensive damage to the tap changer and the transformer.
Of course, the parameter limit values can be changed within defined limits to fit your wishes and system specifications.

The TAPGUARD® 260 can prevent damage not only to your tap changer. By monitoring service intervals, switching tube lifetime (with VACUTAP®), contact wear and oil carbonization (with OILTAP®), it leads to an optimized and condition-based maintenance. Through this, the TAPGUARD® 260 reduces product lifecycle costs and increases reliability. An integrated log book shows the operation and maintenance history of your tap changer.

Prevent a failure of your transformer - trust the TAPGUARD® 260. It knows when the next service is due.

Technical Data



On-load tap changer monitoring

Calculating all important maintenance criteria

Signaling the next pending maintenance

Taking the soot content into account (only OILTAP®)

Calculating the contact wear (only OILTAP®)

Showing the lifetime of the vacuum interrupters of existing MR on-load tap-changers (only VACUTAP®)

Monitoring the on-load tap-changer
   • Torque
   • Load current
   • Temperature
   • Diverter switch operation

Monitoring the motor linkage and the smooth running in the three-column version

Controlling the motor-drive unit heater

Motor Current Index





Siemens LSA


Tap position capture


Current signal

Voltage signal

Resistor contact series


Cooling system control

Basic monitoring of the transformer

Load current, load voltage

Ambient temperature

Tap position (analog, BCD)

Effective and apparent power

Aging rate

Tap-change operation statistics

Upper oil temperature

Winding temperature

Hot spot

Extended monitoring of the transformer

Lower oil temperature

Winding temperature 1, 2, and 3

Second ambient temperature

Oil level of the conservator transformer, OLTC

Dehydrating breather transformer

DGA (Dissolved gas analysis)

Acquiring DGA sensor information (up to 9 gasses)

Moisture in oil (transformer, OLTC)

Total gas content

Cooling system monitoring

Inflow temperature

Outflow temperature

Operating statistics


Monitoring the cooling system

Voltage regulation

Voltage regulation, including line drop compensation

Parallel mode

Customer-specific topology