TITLE: FREQUENCY RESPONSE ANALYSIS OF TRANSFORMER WINDING.

OBJECTIVE: To assess the change in swept frequency response analysis of the transformer winding under the influence of simulated short circuit.

CIRCUIT DIAGRAM: Click to see

DESCRIPTION:

• Frequency Response Analysis for a transformer winding deals with measurement of frequency dependency of electrical response of the transformer winding to applied signal resulting from changes in capacitance or inductance distributions of the winding. It involves measuring impedance over wide range of frequency and comparing it with a reference set.
• Initially the response shows inductive nature in the lower frequency range, in the middle frequency range it has both inductive and capacitive nature and as we proceed towards high frequency it shows capacitive nature.
• The response shows poles and zeroes corresponding to resonances that correspond to natural frequencies and the location of these poles and zeroes change corresponding to any physical change in the winding structure.

EQUIPMENTS:

• Transformer winding
• LCR meter
• 9261 test fixture

PROCEDURE:

• The transformer winding should be connected to the LCR meter along with test fixture as shown in diagram.
• Measurement can be performed with ground and without ground.
• The frequency is to be varied from 50 Hz to 2 MHz.
• The reference set of readings (Z and θ) are the initial readings taken for the original coil without any changes in it.
• The readings are plotted (Z vs f) and (θ vs f).
• A simulated change is introduced in coil like introducing short circuit between different turns of winding and same procedure is repeated.
• Second set of readings are plotted and compared with reference set.

EXPERIMENTAL RESULTS: