Power transformers are the central hub in the field of energy distribution and transmission. As such, their condition is critical for reliable, fault-free operation. Any failures can have serious consequences. The resulting overloads of grid sections can lead to far-reaching supply and production failures. A total failure of the insulation can lead to personal injury as well as to immense damage of property.
Therefore, we have developed a wide range of solutions for testing power transformers that operate in line with international standards.
Common Electrical Tests on Power TransformersShow more
Common Electrical Tests on Power Transformers
Regularly performing a range of standard electrical tests has proven an effective way to gain a reliable insight into the operating condition of your transformers and can extend their lifespan. Mechanical changes to windings, contact problems in the tap changer or at other connections, shorted windings/coils, as well as interruptions or short-circuit of parallel lines can all be diagnosed early by using conventional testing methods. Severe and costly damage can be thereby prevented.
Dissipation/Power Factor & Capacitance Measurement on Power TransformersShow more
Dissipation/Power Factor & Capacitance Measurement on Power Transformers
The condition of the insulation is essential for secure and reliable operation of your transformer. Measuring capacitance and dissipation/power factor helps you to determine insulation condition in bushings or between windings.
Changes in capacitance can, for example, indicate mechanical displacements of windings or partial breakdown in bushings. Aging and degradation of the insulation, coupled with the ingress of water, increase the amount of energy that is converted to heat in the insulation. The rate of these losses is measured as dissipation factor.
Partial Discharge Measurement and Analysis on Power TransformersShow more
Partial Discharge Measurement and Analysis on Power Transformers
Partial discharges (PD), as defined by IEC 60270, are localized dielectric discharges in a partial area of a solid or liquid electrical dielectric insulation system under high-voltage field stress. Partial discharges in a transformer deteriorate its insulation and can lead to failure of the transformer.
Diagnostic PD measurements are recommended after conspicuous measured values, such as increased gas-in-oil values or after a failed PD measurement during acceptance tests.
Sweep Frequency Response (SFRA)Show more
Sweep Frequency Response (SFRA)
Frequency response analysis (often referred to as FRA or SFRA) is a powerful and sensitive method for testing the mechanical integrity of transformer cores, windings, and press frames, in power transformers.
Every electrical network has a unique frequency response – its so-called "fingerprint". Network faults or vibrations can cause changes in this frequency response.
Moisture Analysis on Power TransformersShow more
Moisture Analysis on Power Transformers
Moisture in the solid part of the paper insulation is one of the most important factors regarding the condition of power transformers. Moisture can enter a transformer's insulation from the atmosphere during installation or repair. An increase in moisture content in paper insulation accelerates its aging process. Moisture is also a by-product of the aging process.
Tap Changer AnalysisShow more
Tap Changer Analysis
On-load tap changers (OLTC) play a vital role in regulating the voltage level in the electrical grid. Depending on the load, the transformer turns ratio has to be adapted during operation by the OLTC. These mechanical switching operations can lead to wear and tear of the tap changer contacts over time. Therefore, tap changer analysis focuses on static contact problems of the tap selector and of the diverter switch. In addition, a dynamic resistance and motor current measurement can be performed to analyse the transient switching operation for each tap position.
Know the condition of your transformer to get the most out of your asset
During commissioning and operation it is essential that your power transformer is in good condition. Various influences can impact the expected lifetime throughout a transformer's lifecycle.
Diagnostic testing and monitoring will help you to determine your asset's condition and choose the right corrective measures to ensure reliable operation and extend the transformer's life expectancy.