Sweep Frequency Response Analyzer for Power Transformer Core and Winding Diagnosis
FRAnalyzer - Sweep Frequency Response Analyzer
OMICRON's FRAnalyzer detects mechanical and electrical changes of the core and the winding assembly of power transformers by using the SFRA method. SFRA stands for Sweep Frequency Response Analysis, a worldwide proven technique for measurements in frequency domain that allows examining transformers without costly detanking. By finding winding or core defects after faults, mechanical shocks (e.g. earthquakes) or transportation, it offers a valuable opportunity to improve the reliability of transformers, to reduce maintenance costs and, most of all, to avoid expensive unexpected outages.
Features & Benefits
- Use of the non-intrusive SFRA method – the industry standard for measurements in frequency domain: high reliability of test results
- True-value results due to accurate reproducibility
- Direct measurement in frequency domain (as opposed to time measurement method): no further mathematical handling of data necessary
- Creative software: fast, easy and efficient handling
- Cost saving due to included database solution
- Extremely small sized unit through use of leading edge technology
- Portability resulting from battery operation
- Advanced connection technique ensures a high degree of repeatability
- Delivered in complete firm arrangement designed for field use
Applications
- Transformer check after short circuit testing
- Integrity verification of transformers after transport
- Condition assessment after the occurrence of high transient fault currents
- Routine diagnostic measurement
- Diagnosis after transformer alarm or protection tripping
- Test after significant changes of monitored values (e.g. combustible gases)
- Further inspection after the observation of unusual routine test results
- Scientific investigations
Further Information
How does it work?
A transformer can be represented as an equivalent circuit made up of a multitude of resistive, inductive, and capacitive elements. The frequency response of this network is unique, like a fingerprint. Winding deformation causes one or more of the capacitors in this network to be changed. Changes which can be detected by OMICRON's FRAnalyzer. To identify problems, FRAnalyzer injects an excitation signal into one end of the transformer and measures the returning signal at the other end. Comparing this fingerprint to previous results of the same unit, type-equal-ones or the fingerprint of another phase, allows identifying changes.
- Winding deformation - axial and radial, like hoop buckling, tilting, spiraling
- Displacements between high and low voltage windings
- Partial winding collapse
- Shorted or open turns
- Faulty grounding of core or screens
- Core movement
- Broken clamping structures
- Problematic internal connections