Deep Dive: Top 5 Transformer Predictive Maintenance Capabilities

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APPLICATION: Transmission / Distribution Substation Transformers

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Transformer Load Tap Changer Monitoring

The INCON® 1250-LTC Programmable Load Tap Changer (LTC) Position Monitor relays critical position information between a distribution transformer LTC and the LTC controller, enabling utilities to run their transformers as efficiently as possible.

With over 40 years of proven service in over 33,000 utility transformers around the globe, the 1250-LTC does so much more than just monitor tap position. It is a vital tool that utilities use to predict transformer maintenance and prevent the failure of their LTC’s.

In addition to basic LTC tap position, the 1250-LTC monitors several additional important characteristics related to LTC movement. Programmable alarm options help utilities automate transformer maintenance planning. Check out the top 5 predictive maintenance capabilities:

Top 5 Transformer Predictive Maintenance Capabilities


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It is important for an LTC to pass through the neutral tap occasionally.If it doesn’t the reversing switch may become sticky and inoperable. The 1250-LTC has a programmable alarm that tells the utility if it has been too many days since the LTC has passed through the neutral tap.​

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The 1250-LTC can be programmed to close one of its relays upon completion of each tap change. This can be used as a feedback acknowledgment that the requested tap change was successful.​ If the acknowledgment isn't made, it can be a good indication that maintenance is required.

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Most LTC’s rotate about 9 to 11 degrees with each tap change. The 1250-LTC can measure in increments of 1/10th of a degree. A special feature of the 1250-LTC is its ability to monitor small discrepancies in tap position. A programmable limit can be set to give an alarm when the discrepancy in tap position reaches the limit. Inaccurate tap position can be an early indicator of wear in the LTC mechanism or possible impending failure.

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If, for some reason, the LTC controller gets a faulty voltage reading, the LTC can run away in one direction; a serious condition that can effect transformer operation. The 1250-LTC has a programmable alarm that can be used to cut power to the drive motor if it detects too many tap changes in one direction.

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In the course of its life, an LTC may move up and down through the same few taps. As a result, these taps will have much more wear than the rest of the contacts. The 1250-LTC keeps a count of how many tap changes were made up to and down to every tap. This data helps utilities plan maintenance and replacement of the LTC contacts.

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Load Tap Changer Position Monitors

INCON® Load Tap Changer (LTC) Position Monitors relay critical position information between the LTC and the LTC controller, enabling utilities to control their distribution transformers with precision accuracy. Utilities can also feed the LTC position to the central dispatch center through the SCADA system (Supervisory Control and Data Acquisition) to know the exact position for a network of many transformers.​​


Here's The Benefits:

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Balance Loads

Accurately and intelligently balance the loading of a network of transformers. 

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Voltage Regulation

Regulate line voltage by adjusting feeder voltage.

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Reduce Costs

Reduce power costs by providing the minimum line voltage required.

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Predictive Maintenance

Deploy predictive transformer maintenance with intelligence.

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