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Transformer monitoring and it benefit.

Transformer monitoring and it benefits


There are a variety of sensors used in transformer monitoring, each designed to monitor specific parameters of the transformer’s operation. Here are some common types:

What are some common sensors used in transformer monitoring?

  1. Optical Sensors: These are used for various diagnostic methods such as partial discharge, dissolved gases, temperature and other important sensing, and optical detection.

  2. Oil Level Sensors: These monitor the level of oil in the transformer, which is crucial for cooling and insulation.

  3. Pressure Switches: These are used to detect abnormal pressure levels in the transformer, which could indicate a fault.

  4. Tap Position Sensors: These monitor the position of the tap changer, which adjusts the transformer’s output voltage2.

  5. Load Tap Changer (LTC) Position Sensors: These monitor the position of the LTC, which adjusts the transformer’s output voltage to maintain it within a certain range.

  6. Coupling Capacitors: These are highly sensitive partial discharge (PD) sensors used to decouple PD from the monitored conductor3.

  7. Radio Frequency Current Transformers (RFCT): These provide non-invasive, directionally sensitive PD detection on electrical equipment by detecting activity in the ground connection3.

  8. Dissolved Gas Sensors: These monitor the gases dissolved in the transformer oil, which can indicate various types of faults4.

  9. Bushing Power Factor and Capacitance Sensors: These monitor the power factor and capacitance of the transformer bushings, which can indicate insulation problems.

  10. Temperature Sensors: These monitor the temperature of the transformer, which can indicate overloading or cooling problems.

These sensors provide valuable data that can be used for condition monitoring, fault detection, and preventive maintenance of transformers.

How do these sensors communicate with the monitoring system?

The sensors in a transformer monitoring system communicate with the monitoring system in a variety of ways. A Power Transformer Monitor (PTM) is a specialized electrical utility device equipped with sensors that collect, process, and measure information relative to the current flowing through a distribution or power transformer. The process is known as condition monitoring of transformers and reports to a control system such as SCADA/MDM where an analytic platform can display interpretable transformer data. PTMs are usually connected to temperature sensors which are Resistor Temperature Devices (RTDs) for which there are thermometer wells installed in the tank. In the event that the transformer does not have a thermometer well, Advanced Power Technologies manufactures a convenient magnetic mount probe that is as intrinsically accurate as our thermometer and can be retrofitted onto any flat surface. In the event that winding temperature is needed, a split-core current transformer is supplied for continuously calculating the transformer’s winding hottest spot temperature. Multiple types of sensors can be connected to the PTM to monitor tap position of the OLTC, Bushing C capacitance just to name a few of the monitored parameters. Remote monitoring and communication capabilities allow utilities to conduct “predictive” maintenance of transformers, which means conducting maintenance only when a parameter starts deviating from a pre-set standard. This typically does not occur at a pre-determined interval2. Remote management allows operators to “see” how a transformer is operating, and send someone to fix it when, and only when, it’s necessary.

How can I get started with transformer monitoring?

Getting started with transformer monitoring involves several steps:

  1. Understand Your Needs: Determine what you want to achieve with transformer monitoring. This could be improving safety, increasing reliability, optimizing maintenance, improving energy efficiency, or providing data for analysis1.

  2. Choose the Right Monitoring System: There are various transformer monitoring systems available in the market. Some of the popular ones include the INCON® Distribution Transformer Monitor (DTM) by Franklin Grid Solutions and the Transformer Electronic Control (TEC) system by ABB. These systems provide continuous, meter-grade precision performance monitoring of transformers.

  3. Install the Necessary Sensors: Install the necessary sensors on your transformer. These could include optical sensors, oil level sensors, pressure switches, tap position sensors, Load Tap Changer (LTC) position sensors, coupling capacitors, Radio Frequency Current Transformers (RFCT), dissolved gas sensors, bushing power factor and capacitance sensors, and temperature sensors.

  4. Connect the Sensors to the Monitoring System: Connect the sensors to the monitoring system. This could involve making physical connections or setting up wireless communication.

  5. Configure the Monitoring System: Configure the monitoring system to monitor the parameters you are interested in. This could involve setting thresholds for alarms, configuring data collection intervals, and setting up communication with a control system such as SCADA/MDM.

  6. Test the Monitoring System: Test the monitoring system to ensure it is working correctly. This could involve checking the accuracy of the sensor readings, testing the communication with the control system, and testing the alarm notifications.

  7. Train Your Staff: Train your staff on how to use the monitoring system. This could involve training them on how to interpret the data, how to respond to alarms, and how to maintain the system.

  8. Maintain the Monitoring System: Regularly maintain the monitoring system to ensure it continues to function correctly. This could involve cleaning the sensors, checking the communication links, and updating the software.

By following these steps, you can successfully implement a transformer monitoring system and start reaping the benefits of improved safety, increased reliability, optimized maintenance, improved energy efficiency, and valuable data for analysis. Transformer monitoring is a process of collecting, processing, and measuring information related to the transformer's condition and performance. The goal of transformer monitoring is to prevent faults, increase reliability, and optimize maintenance. According to a, transformer monitoring actively monitors various operating characteristics to make sure they are functioning properly. Transformer monitors collect data and send alarms to notify the user if something looks off. Some of the benefits of transformer health monitoring include:

- Detecting faults in real time based on current, voltage, temperature, and internal flux.

- Increasing system reliability and stability.

- Preventing faults and losses of the power supply, which significantly benefits utility consumers.

- Preventing overcurrent and overtemperature.

- Detecting incipient faults and assisting in preventing failures and unplanned outages.

- Enabling condition-based maintenance.

- Improving staff safety and environmental protection.

- Providing valuable data for a root cause analysis and an investigation in case of a failure


The origin of transformer monitoring concept dates back to the early 1900s, when methods to measure oil temperature and simulate winding hotspot temperature were developed. These methods were used to control the cooling system and increase the power capacity of transformers. Nowadays, transformer monitoring involves various sensors and devices that collect, process, and measure information related to the transformer's condition and performance.


  • Transformer Monitoring: A process of collecting, processing, and measuring information related to the transformer’s condition and performance.

  • Benefits: Preventing faults, increasing reliability, optimizing maintenance, improving safety, and providing data for analysis.

  • History: Originated in the early 1900s with methods to measure oil and winding temperature. Evolved with various sensors and devices to monitor various operating characteristics.

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