Saturation in current measurement is a serious event that can result in inaccuracies in readings, equipment damage, safety risks, inefficient maintenance, as well as failures and loss of reliability in systems.

Current monitoring is the process of recording, monitoring, and analyzing the behavior of electrical currents present in an electrical system. Through this method, it is possible to ensure the safe and reliable operation of numerous electrical systems and to allow the early detection of problems and the implementation of preventive measures to mitigate them.

"[...] This procedure allows monitoring of consumption, power, and voltage data, providing a detailed diagnosis for companies, industries, and residences." - Source: 

https://loja.br.abb.com/blog/post/monitoramento-de-corrente

What are saturations and how do they occur?

Saturation occurs when the current measurement device (current sensor) cannot respond linearly to an increase in current, 

resulting in inaccurate or completely wrong readings

This can compromise the functionality of protection systems, such as circuit breakers and relays, resulting in operational failures and potential hazardous situations, putting the safety of the technical team at risk.

Inaccurate measurements can hinder preventive and corrective maintenance, leading to inadequate interventions that increase operating costs and system downtime.

 results in the orientation of elementary dipoles in relation to the direction of the magnetic field. The quantity of these dipoles is finite, and therefore, at a certain point, practically all dipoles are oriented in relation to the magnetic field. When this happens, the relationship between flux and current, which was linear, becomes non-linear.

This saturation point is reached when there are no more elementary dipoles available to be oriented, thus, the loss of linearity brings unpredictability in the processes involving these equipment because no matter how much the quantities increase, saturation prevents a proportional increase in magnetic flux.

This unpredictability can negatively impact the efficiency and safety of the electrical systems in which the transformers are installed. In current meters that use ferromagnetic cores, such as current transformers and Hall effect sensors, saturation of the ferromagnetic material is a phenomenon that can compromise the accuracy of measurements and lead to various undesirable consequences.

Main causes of saturation in current measurement

Current above the sensor's measurement range: 

If the actual current exceeds the range supported by the sensor, it will saturate, providing inaccurate readings.

 The presence of harmonics or other distortions in the current waveform can lead to sensor saturation, especially in sensors based on current transformers.

Current spikes, such as those caused by lightning strikes or motor starts, can saturate the sensor for a brief moment, compromising the reading.

 Cheap or low-quality current sensors may have lower dynamic range and be more prone to saturation.

Consequences of saturation in current measurement

The main consequence of saturation is the loss of accuracy in primary current measurements. This occurs because the relationship between primary and secondary current becomes distorted when the CT core saturates.
This distortion can lead to incorrect current readings, which can have various negative impacts, such as:

protection relays may be incorrectly activated, causing unnecessary interruptions in the system.

 if the actual current is greater than the measured one, cables and equipment may be undersized and experience premature failures.

inaccurate energy consumption measurements can make it difficult to identify areas of excessive consumption and implement energy efficiency measures.

Saturation can generate excessive heat in the CT, damaging the equipment and other components of the electrical system, as well as melting the CT insulation, causing short circuits and even fires.

The distortion of the secondary current caused by saturation can lead to improper operation of protection relays. This can cause unnecessary interruptions in the system, as well as make it difficult to identify real faults.

In addition to the consequences mentioned above, saturation in CTs can also cause other problems, such as:

saturation can generate vibrations and noise in the CT, which can be annoying and even harmful to health.

 saturation can generate electromagnetic interference (EMI), which can affect other electronic equipment.

How to prevent and avoid this phenomenon?

Fortunately, there are some measures that can be taken to prevent saturation in current measurement.

Filtering techniques and surge protectors can help reduce the amount of noise and distortion present in the current signal and protect the sensor against momentary current spikes, reducing the risk of saturation. However, choosing an appropriate and high-quality current sensor is essential to ensure harmony in current measurement and monitoring.

 is an advanced current meter that stands out for the absence of ferromagnetic material in its core, providing non-saturation and offering significant advantages over traditional current transformers (CTs).

This device presents itself as a solution to the saturation problem, as it has a hollow core, ensuring safety and stability through shielding against external magnetic fields.


Do you want to know more about this product? 

Saturation in Current Monitoring and the Rogowski Sensor Current Meter

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