Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

Leakage Reactance DefinitionIn a transformer, not all the flux links both the primary and secondary windings. Some flux links with only one winding, called leakage flux. This leakage flux causes self-reactance in the affected winding.This self-reactance is also known as leakage reactance. When combined with the transformer’s resistance, it forms impedance. This impedance causes voltage drops in both the primary and secondary windings.Resistance of TransformerThe primary and secondary windings of

Eddy Current DefinitionAccording to Lenz’s law, when a conducting loop is exposed to a changing magnetic field, it generates an emf that induces a current opposing the change. Similarly, when a magnetic field changes through a conducting body, like a filament or a slab, it causes currents to flow through the material’s cross-sections.These currents are given the name eddy currents after the water eddies that are small swirling whirlpools observed in lakes and oceans. These eddy current loops can

What is the Maintenance of Transformers ?Maintenance of transformers is essential to ensure their safe, stable and efficient operation, and the following are some common maintenance measures:Periodic inspectionAppearance check: Check whether the transformer shell is damaged, deformed, and leaking oil.Oil temperature check: Use an oil temperature gauge to measure the oil temperature and ensure that it is within the normal range.Oil level check: Observe the oil level in the oil pillow. If the oil

What are the Types of Transformers Windings?Types of Transformers Core type transformers have windings on outer limbs Shell type transformers have windings on inner limbsMainly there are two types of transformer Core type transformer Shell type transformerTypes of Winding used for Core Type TransformerCylindrical WindingsThese windings are layered type and uses a rectangular or round conductor shown in Fig.(a) and (b). The conductors are wound on flat sides shown in Fig.(c) and wound on the rib

What is Sweep Frequency Response Analysis Test ?SFRA Test DefinitionSFRA test of transformer is a method used to assess the condition of transformer windings by analyzing their frequency response to electrical inputs.Purpose of SFRA testing Assessing the mechanical integrity of windings: Detecting whether the windings are displacements, deforms or short circuits. Monitoring the health of the transformer:Changes in the condition of the transformer windings can be tracked by comparing historical d

The purpose of the pulse testDetection of partial dischargePartial discharge refers to the discharge phenomenon that occurs at the air gap or impurity in the insulation material under the action of high voltage electric field, which may gradually destroy the insulation system.Evaluate the degree of insulation agingBy analyzing the characteristics of partial discharge, you can evaluate the degree of aging of the insulation material.Identify potential insulation failuresProblems such as moisture,

What are Voltage and Turn Ratio Test of Transformer?Transformer Turn Ratio DefinitionThe transformer turn ratio is defined as the ratio of the number of turns in the HV winding to the number of turns in the LV winding.Voltage Ratio Test of TransformerThis test checks if the voltage ratio matches the expected turn ratio by applying voltage to the HV winding and measuring the induced voltage in the LV winding.Testing Procedure First, the tap changer of transformer is kept in the lowest position an

Winding Resistance Test DefinitionThe winding resistance test of a transformer checks the health of transformer windings and connections by measuring resistance.Purpose of Winding Resistance TestThis test helps in calculating I2R losses, winding temperature, and identifying potential damage or abnormalities.Measurement MethodsFor star connected winding, the resistance shall be measured between the line and neutral terminal.For star connected autotransformers the resistance of the HV side is meas

What is Polarity Test of Transformer ?Polarity Test DefinitionA polarity test of transformer is a method to ensure correct polarity alignment when connecting transformers in parallel.Dot ConventionThe dot convention identifies the polarity of windings in a transformer, showing how voltage is induced. If a current enters the dotted terminal of one winding, then the voltage induced on the other winding will be positive at the dotted terminal of the second winding. If a current leaves the dotted te

Open and short circuit tests are performed on a transformer to determine the: Equivalent circuit of transformer Voltage regulation of transformer Efficiency of transformerOpen Circuit Test DefinitionThe open circuit test of a transformer checks the core losses and parameters of the shunt branch by connecting instruments to the LV side and keeping the HV side open.Open-circuit Test (No-load Test) Steps: Ensure that the transformer is disconnected from the power supply to ensure safety. Open the l