power transformer on-load tap-changer

So we're talking aboutPower transformer on-load tap-changer. Many people think that this is just a set of numbers from a passport, a few calculations and that’s it. In reality, it is much more complicated. Often when replacing a transformer or carrying out scheduled maintenance, we see errors in estimating parameterson-load tap-changerlead to serious consequences - from reduced efficiency to equipment failure. And most importantly, this is not always immediately obvious; the problem can manifest itself gradually, in the form of small deviations, which then accumulate. So let's figure out what you need to consider.

What is a transformer on-load tap-changer and why is it important?

RPN (Resulting Voltage Parameter)power transformer is a complex characteristic that describes the relationship between input and output voltage, as well as current. It takes into account not only the nominal values, but also losses in the transformer, temperature changes, and other factors. Importanceon-load tap-changeris that it allows you to accurately assess the performance of the transformer in various load modes and avoid overloads or underloads. Wrong estimateon-load tap-changercan lead to suboptimal operation of the power grid, increased energy losses, and in extreme cases, equipment damage.

We often encounter situations where, when replacingon-load tap-changerthey simply take the transformer closest in rating, without taking into account its characteristics. This usually leads to new equipment operating inefficiently, for example, when the load is below rated, its losses become too high. Higher loads may require additional cooling, and severe overloads may result in insulation damage. So, choiceon-load tap-changer- this is not just a formality, it is a responsible step that requires careful analysis.

Effect of temperature on on-load tap-changer

Do not underestimate the effect of temperature on transformer parameters. With increasing temperature, the characteristics of the magnetic circuit change, and thereforeon-load tap-changer. This is especially important to consider for transformers operating under conditions of increased thermal loads. For example, in industrial plants where there are frequent overloads, it is necessary to carefully monitor the temperature of the windings and take into account its effect onon-load tap-changerwhen calculating network parameters. We at Wenzhou Qiaonasen Electrical Equipment Co.,Ltd always take this factor into account when designing and supplying transformer equipment.

We often see a problem - a transformer is initially designed for a certain temperature range, and then it is operated at higher temperatures. This leads to deterioration of performance and reduced service life. In such cases, recalculation of parameters is requiredon-load tap-changertaking into account new operating conditions or, as a last resort, replacing the transformer with a more powerful and heat-resistant one.

Calculation of on-load tap-changer parameters: main stages

Calculation processon-load tap-changerquite complex and requires the use of specialized software and experience. It includes several stages: collecting data about the transformer (rated voltage, current, losses), determining load conditions, calculating losses in the windings and magnetic circuit, as well as determining the voltage parameters at the input and output of the transformer. In practice, complex design schemes are often used for this, taking into account all possible factors affecting the operation of the transformer.

Particular attention should be paid to calculating losses in windings. They depend on current and temperature, so it is necessary to take into account their change depending on the load mode. Insufficient accuracy in calculating losses can lead to errors in determiningon-load tap-changerand, as a consequence, to the wrong choice of transformer or disruption of the electrical network. We at Wenzhou Qiaonasen Electrical Equipment LLC use modern software systems for accurate calculationson-load tap-changerand provide our customers with reliable and efficient equipment.

Practical examples and mistakes

Let's remember the case with one of our clients - a large industrial complex. When replacing an old transformer with a new one, a miscalculation was made in the assessmenton-load tap-changer. The new transformer was not powerful enough to operate the equipment during peak loads, which led to its overload and subsequent failure. The error was caused by an incorrect assessmenton-load tap-changerand ignoring the power safety factor. Obviously, this situation could have been prevented with a more thorough analysis of the transformer parameters and taking into account possible overloads.

Another common mistake is insufficient control over the condition of the transformer during operation. If parameters are not measured regularlyon-load tap-changer, then you may not notice the gradual deterioration of its characteristics and miss the moment when it is necessary to make repairs or replacement. Regular monitoring of parameterson-load tap-changerallows you to identify problems in a timely manner and avoid serious consequences. Wenzhou Qiaonasen Electrical Equipment Co., Ltd. offers services for diagnostics and condition monitoring of transformer equipment.

Problems with inductance and reactive power

Sometimes when calculatingon-load tap-changerDifficulties arise when taking into account inductance and reactive power. This is especially true for transformers operating in networks with a high level of harmonic distortion. Incorrect calculation of these parameters can lead to an increase in reactive losses, a decrease in power factor and a deterioration in power quality. In such cases, it is necessary to use special calculation methods and take into account the effect of harmonic distortion on the operation of the transformer. Wenzhou Qiaonasen Electrical Equipment Co., Ltd. provides consultations on issues of taking into account inductance and reactive power in calculationson-load tap-changer.

It is also worth considering thaton-load tap-changermay vary depending on the operating mode of the transformer - in normal mode, during a short circuit, during no-load. For an accurate calculation, it is necessary to take into account all these modes and their influence on the transformer parameters. We at Wenzhou Qiaonasen Electrical Equipment Co., Ltd. carry out a comprehensive analysis of parameterson-load tap-changerin various operating modes to provide our customers with maximum equipment reliability and efficiency.