C. Kumaravelu

Bio: C. Kumaravelu is an academic researcher. The author has contributed to research in topics: Fault current limiter & Fault indicator. The author has an hindex of 1, co-authored 1 publications receiving 7 citations.

Identification and location of breakdown in windings

Abstract: It is possible to estimate the location of the fault based on a study of the resonant frequencies of the winding current. It is shown that the nearest neighbourhood rule based on a clustering approach provides a good framework for fault location. Additional signal acquisition in the form of the tank current can considerably simplify the identification of a fault to ground. Experimental investigations are performed in order to identify and locate breakdown in windings.

Virtual Instrument for Lightning Impulse Tests

Abstract: We propose an objective formulation of the impulse analysis problem from a signal analysis viewpoint. The winding response is quintessentially that of a deterministic network to a finite energy signal, with breakdown and partial discharge being inherently nonlinear events. A significant improvement to the acquisition of waveforms is demonstrated by a virtual instrument approach. It retains the advantages of the time- and frequency-domain methods. The drawbacks of the transfer function method are highlighted and a new piecewise linear approach is proposed for analysis. Experiments on a discrete lumped parameter model of the winding are used to validate the PXI based instrument.

The influence of winding type on the recognition of partial discharges [power transformer testing]

Abstract: An instrumentation scheme is proposed for the acquisition of waveforms during the lightning impulse test on transformers. Three filters segregate the response into distinct frequency bands. As partial discharge signals primarily influence the high frequency behaviour, experiments are reported on disc, interleaved disc and layer windings.

A Lock-in Technique for PD Measurement during Impulse Tests

Abstract: A method is proposed for recognizing PD events within a winding during impulse tests using a lock-in amplifier technique. The resonant frequencies of the winding serve as the basis of selection of the lock-in amplifier reference frequencies. It is implemented with a virtual instrument and validated with an independent stand-alone lock-in amplifier. A physical model of a winding with discrete elements is used to demonstrate the results. A theoretical basis for the instrument is established using an 'abc' model of PD along with a linear discrete winding model. The influence of location of PD is also addressed. The method will provide online recognition of PD during the impulse test and can be adapted for onsite measurements.

Online assessment of winding deformation based on optimised excitation

Abstract: On line assessment of winding deformation in a power transformer can be performed via a bushing tap excitation with optimized high frequency excitation. A benchmark layer winding is used to validate the use of the specific high frequency excitation. Axial displacement, compression and buckling of the winding are simulated and the changes identified. Measurements are performed on a voltage transformer to verify the suitability of the technique. The procedure will result in a considerably shorter time for measurement.

Fuzzy logic based impulse test analysis

Abstract: A fusion of hard and soft computing is proposed for the impulse analysis problem. An optimal hardware platform for the data acquisition and a minimal set of simulations form the hard computing element. As the number of simulations can become unbounded to cater to all types of faults, a soft computing approach based on fuzzy logic is proposed. This can lead to automation of impulse analysis function.