MODULE: Testing And Commissioning Of Electrical System ( O&M 4 )


Introduction: Basic theory of insulation; Dielectric loss, Power factor, Dissipation factor; GST, GST-G and UST mode for testing.

Testing Techniques: AC test and DC test, advantages and disadvantages of each.

Transformer Testing: IR, AC or DC High-Pot, tan d, TTR, Polarity, Voltage balance, Induced potential, DGA, DC winding resistance; Acceptable values.

Oil – Definition of terms used in oil characteristics; Acceptable values for BDV, tan d, Specific resistance, Neutralisation value, Interfacial tension, Gas content, Oil filtration techniques- Fuller’s earth, Enervac and Velcon system; DGA (Dissolved Gas Analysis), Principle, Roger’s method, Limiting value of Hydrocarbon concentrations, Case studies, Condition monitoring, Recommended test and periodicity.

Generator/Motor Testing: IR, PI, DC High-Pot, Step voltage, tan d, PF-tip up, DC winding resistance.

Switchgear Testing: Visual and mechanical inspection; IR and DC High-Pot in Circuit Breaker open and closed position, tan d,Contact resistance, Time travel analysis, Thermo graphic survey, CT & PT testing, Protective relay and functional operation.

Cables and Accessories Testing: IR, DC High-Pot, tan d.

Battery system Testing: Definition of AHR rating and Volt / Cell for Lead acid and Ni-Cd Batteries; Periodic inspection procedures for Battery and Battery Chargers; Service test for given load cycle, Connection resistance test and Battery impedance test.

Commissioning and Startup of Electrical System: Pre Commissioning checks of Generators, Motors and Transformers; Connectivity and Phasing out; Generator dry out; Short-circuit heating, and testing of Protective Relay operation; Synchrochecks.

Documentation and record keeping: Typical test format for periodic maintenance testing.