TRANSFORMER TESTING
Power transformer testing involves a series of assessments to ensure the proper functioning, performance, and safety of a power transformer. These tests help identify any defects, insulation breakdown, or operational issues that could affect the transformer's reliability and efficiency. Here are some common tests performed on power transformers:
Transformer Turns Ratio Test: This test measures the ratio of the number of turns between the high-voltage and low-voltage windings. It ensures that the transformer is correctly designed and wound, and that the turns ratio is within specified tolerances.
Insulation Resistance Test: The insulation resistance test evaluates the insulation integrity of the transformer windings. It measures the resistance between the windings and the transformer tank or ground to identify any insulation deterioration, contamination, or moisture ingress.
Transformer Winding Resistance Test: This test measures the DC resistance of the transformer windings to determine their overall health and to identify any abnormal or unequal resistance values. Deviations from the expected values may indicate shorted turns or loose connections.
Transformer Polarity Test: The polarity test verifies the proper connection of the transformer windings and the correct phasing of the transformer. It ensures that the primary and secondary windings are properly aligned and will provide the intended voltage transformation.
Transformer Impedance Test: The impedance test determines the equivalent impedance of the transformer, including its resistance and reactance. It helps evaluate the transformer's capability to handle fault currents and its voltage regulation performance.
No-Load Loss and Excitation Current Test: This test measures the transformer's core losses, including the no-load loss and the excitation current required to establish the magnetic field. It helps assess the transformer's energy efficiency and core condition.
Short-Circuit Impedance Test: The short-circuit impedance test determines the equivalent impedance of the transformer when subjected to a short-circuit condition. It provides valuable information about the transformer's ability to withstand fault currents and its contribution to the overall system fault level.
Dissolved Gas Analysis (DGA): DGA involves analyzing the concentration and type of gases dissolved in the transformer's insulating oil. It helps detect and diagnose potential faults, such as overheating, arcing, or insulation degradation.
Dielectric Breakdown Voltage Test: This test evaluates the dielectric strength of the transformer's insulating oil by measuring the voltage at which the oil breaks down. It helps assess the oil's ability to withstand electrical stress and prevent arcing or flashovers.
Partial Discharge Test: The partial discharge test detects any partial discharges occurring within the transformer insulation. It helps identify weak spots or insulation defects that could lead to insulation breakdown over time.