This Thesis Presents Condition Monitoring Of Transformers Using Partial Discharge Acoustic Emission (Pdae) Signals, Accomplished Mainly Through Experimental Studies. To Understand The Acoustic Wave Propagation Behavior And To Get The Proper Experimental Tank Dimensions, Simulation Studies Are Carried Out Using Finite Element Method (Fem) Software (Ansys 10.0). Based On The Simulation Results And Actual Transformer Dimensions, A Model Transformer Tank Of 60 Cm In Length, 60 Cm In Width And 60 Cm In Height Is Fabricated In House And Used For The Experimentation. To Simulate Different Types Of Partial Discharges In Transformer, Three Different Electrode Systems Are Fabricated In House And Used For The Experimentation. Acoustic Emission (Ae) Signal Produced By Partial Discharge (Pd) Is Picked Up By The Ae Sensor Mounted On The Tank Surface And Stored For Further Analysis In The Computer. Experiments Are Conducted Exhaustively With All Possible Cases In Laboratory And A Few Measurements Are Also Taken On Actual Transformers. The Experimental Results Are Analyzed Using Fast Fourier Transform (Fft) For Pd Classification. Two Parameters, Peak Frequency And Median Frequency Are Used To Quantify The Frequency Spectrum. Discrete Wavelet Transform (Dwt) And Wavelet Packet Transform (Wpt) Are Used For The Analysis Of Measured Ae Signals. A Comprehensive Technique For Selection Of Mother Wavelet And Selection Of Number Of Decomposition Levels Are Proposed. Energy Distribution In Different Frequency Bands Of Dwt Decomposed Signal And Wpt Decomposed Signal Is Obtained. These Parameters Are Used For Classification Of Pds. The Identification And Classification Of Two Simultaneous Pd Sources Employing Ae Signals Is Attempted By Analyzing The Ae Signals Using Dwt, Wpt, Box Counting Fractal Dimension And Lacunarity. A Non Iterative Source Location Algorithm Employing Four Ae Sensors Is Proposed. The Proposed Algorithm Is Successfully Applied To Both The Experimental Data And The Published Data From Literature. A Comprehensive Method For Signal Arrival Time