How to Ensure Stable Voltage with a Single Phase Power Transformer
In sensitive loads, remote applications and in single-phase distribution systems, voltage stability is directly related to reliability of service. A single phase power transformer plays a crucial role in this equation: it lowers transmission level voltages to levels which are acceptable to the load; it compensates for fluctuations in voltage brought about by changes in load; it compensates for voltage fluctuations due to line impedances; it compensates for voltage fluctuations due to disturbances in the grid. However, not all transformers are created equal. To achieve true voltage stability, careful design, precision manufacturing and an understanding of the application environment are required. In our role as a single-phase power transformer manufacturer, Jiangsu Ryan Electric Co., Ltd. engineers solutions to address the problem of voltage instability from the ground-up, so as to ensure the output stability in the extreme conditions.
Optimized Core Design for Flux Stability
The magnetic core is what makes a single phase power transformer work well to convert energy from the primary coil to the secondary coil. The output voltage will change if the flux density is not stable. Ryan Electric is using high permeability cold-rolled (C.R.) grain-oriented (G.O.) silicon steel with step lap mitered joints, which minimize air gaps and the magnetizing current required to put flux into the steel. The design ensures that the core will not be saturated even during an overvoltage transient and ensures that the input and output voltage of the transformer are linearly related. In addition, the cores are precision stacked on automatic machines so that they are all stacked under the same lamination pressure and alignment to prevent hot spots and mechanical vibration which may result in harmonic distortion. The result is a single-phase power transformer that is predictable and will keep the secondary voltage in a narrow tolerance band of any fluctuation of primary voltage.
Precision Winding and Turns Ratio Accuracy
Voltage regulation in a single phase power transformer is most important dependent on the actual turns ratio of the primary to the secondary coil. The output voltage may differ from nominal values, even if the geometry of the winding or positioning of the conductor is only slightly different. Ryan Electric uses computer-controlled winding machines to achieve precise tension, spacing and layering to exactly reproduce the designed ratio. Our VPI and cast resin dry-type transformers are treated with VPI to make the windings tight, firm and will not be shaken or bent by the thermal and electromagnetic forces. In oil-immersed units, we use high quality copper conductors of optimum cross section, which reduce the resistive voltage drop. Our CNAS accredited laboratories carry out turns ratio testing and verify vector group for each transformer for every power transformer and make sure your single or three phase transformer supplies the correct voltage for your application.
Tapped Windings and On-Load Adjustment Capabilities
The conditions of the grid seldom remain constant and a fixed ratio, single phase power transformer may not be able to handle the long-term voltage changes because of seasonal loading or the far end conditions of the feeders. To solve this, Ryan Electric has transformers with tapped primary or secondary winding, which have several voltage ratios and can be selected in the process of installation and maintenance according to the actual situation of the site. Further, for more dynamic applications, we offer on-load tap changers (OLTC) that can be integrated with our single-phase power transformers, enabling voltage changes without interruption to services. This is particularly helpful for renewable energy systems, remote industrial plants and utility distribution systems with different voltage levels throughout the day. Our single phase power transformers with taps or OLTC devices can actively adjust the output voltage, allowing the output to maintain stable power supply to the connected equipment and extending the service life, thereby reducing the process interruption caused by the change.
Rigorous Testing and Thermal Performance Validation
It is not only that the stability of voltage is dependent on the electrical design of the equipment, but the thermal characteristics of the equipment also have a significant impact on voltage stability. However, if the single phase power transformer is not intended to offset the rise in resistance during operation, then the output voltage will, naturally, decrease. Ryan Electric performs full load heat tests in our 35 kV test bay and 110 kV test bay, while also testing the performance of voltage regulation and the temp gradient of the winding and oil/resin. After that, optimization of cooling technology is achieved with optimized oil circulation, fin radiators or natural air convection, which reduce the temperature rise and stabilize the values of the resistance. Ryan Electric has single-phase solutions that make uncertainty reliable for years and years--and trusted by clients such as Microsoft and State Grid for more than 80 countries.
