Services

Current Transformer Testing

Exciting Current Test

Typically part of preventive maintenance test procedures, the exciting current test is also performed during commissioning, acceptance, and after fault/trip.  The Exciting Current Test provides information and measurement on abnormal core grounds, winding faults (shorts and open circuits), manufacturing defects, and load tap changer problems.

Insulation Resistance

The insulation resistance test is a direct current evaluation test of the insulation and gives a reliable indication of the presence of moisture, contamination, or breakdown in the insulation. This test also establishes a benchmark for future comparative tests.

Transformer Turns Ratio

This test can detect shorted turns in the windings or a defective tap changer. The Turns Ratio Test (TAR) will detect and confirm a difference in voltages between phases. This means, that your transformer is not operating up to the manufacturer’s specifications and is not producing proper output voltages. This is also an early indication of transformer failure. It can also be used for transformer acceptance testing when a new transformer is installed. This will also be a base line for future diagnostics.

Winding Resistance

Winding Resistance Test determines the I2R losses in the transformer, and as a benchmark for assessing possible damages in the field.  As a  routine test procedure, this procedure is used to determine abnormalities due to loose connections, broken strands of conductors, high contact resistance in tap changers, high voltage leads, and bushings.

Generator Testing

Insulation Resistance

Winding Resistance

Power Factor

Partial Discharge (Online)

Electro Magnetic Interference (Online)

Insulation Power Factor

Better known as the “DOBLE Test”, IPF or insulation power factor test is the most comprehensive measurement of insulating properties of a power transformer or any apparatus with a winding.  Elements such as deterioration, contamination, moisture, and heat can breakdown dielectric strength.  Insulation Power Factor Testing measures the dielectric losses due to leakage current thru the insulation.

Insulation Resistance

The insulation resistance test is a direct current evaluation test of the insulation and gives a reliable indication of the presence of moisture, contamination, or breakdown in the insulation. This test also establishes a benchmark for future comparative tests.

Winding Resistance

Winding Resistance Test determines the I2R losses in the transformer, and as a benchmark for assessing possible damages in the field.  As a  routine test procedure, this procedure is used to determine abnormalities due to loose connections, broken strands of conductors, high contact resistance in tap changers, high voltage leads, and bushings.

Insulating Oil Laboratory

Transformer oil analysis is a useful, cost effective, and predictive solution for condition-based maintenance, For years, Dissolved Gas Analysis (DGA) together with Oil Quality tests has been the industry-accepted method for detecting incipient faults. monitoring suspected transformer assets, test theories or explanations of failures, and
to ensure that new transformers are healthy thru benchmarking. The solution of the Dissolved Gas Analysis is anchored on the proven idea that transformers, during its service life, generates combustible and decomposition gasses. These gasses are essentially from various insulation, under different levels of thermal, electrical, or mechanical stress.

WESTCO’s insulating oil laboratory has been designed from the ground up with our core values of Mastery | Integrity | Care | Excellence as its very foundation. Gone are the days that you second-guess “PASS or FAIL” reports. The WESTCO difference is that we just don’t leave the numbers for you to decipher, we provide sound electrical interpretations based on chemical results, providing the end-user the what, why, and how.

The following oil tests are available from WESTCO’s Insulating Oil Laboratory:

Test Method ASTM Method Test Significance Units of Measurement
Dissolved Gas Analysis (DGA D3612 Identification of gas parts per million (ppm), which indicates the amount of contaminant in the oil. Various gasses that dissolve in oil indicates the types of thermal and electrical stress occurring within the transformer ppm
Moisture Content D1533 Even in minute quantities, water or moisture is extremely dangerous for power equipment. Moisture accelerates the deterioration of insulating oil and paper insulation ppm
Neutralization (Acid) Number D664 Acid Number test is used to determine the total acid value of the transformer oil. As acid value increase, the insulating quality of the oil decreases. mg
KOH/g
Interfacial Tension D971 The IFT or Interfacial Tension measures the tension between water and oil at the point of interface. The IFT test is determines the presence of oil decay products and soluble contaminants from solid insulating materials dynes/cm
Dielectric Breakdown Voltage (DBV) D1816 The DBV test determines the strength of an insulating oil sample to withstand electrical voltage without failure. Contaminants such as moisture, or particulates can compromise the insulation properties of oil. kV
Power Factor / Dissipation Factor D924 The Oil Power Factor Test measures the leakage current through an insulating oil. This test also determines dielectric losses of the oil, or the energy that is dissipated as heat %
Color D1500 Transformer oil color is determined by means of transmitted light. This is given a numerical value (0-5) based on comparison with a series of color standards or color wheel. 0-5
Visual Examination D1524 The transformer insulating oil is visually examined by passing a beam of light to determine transparency and identify foreign contaminants. Contaminated Oil shows poor transparency, clouding, or the visual evidence of foreign particles. Bright, Dar, Clear of Particles

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Corrosive Sulfur

Corrosive sulfur and the effect that it has in transformer systems can be significant. The extent of the corrosion damage caused by sulfur, if left unchecked can cause failure of the apparatus. Sulfur is found in many materials of transformer construction including the copper, paper insulation, gaskets and oil. Not all sulfur is considered corrosive but the tendency to operate transformers at substantially higher temperatures can aggravate an already present corrosive sulfur condition or convert stable compounds into reactive ones that will cause damage.

Oil Filtration

Potential Transformer

Exciting Current Test

This test can detect shorted turns in the windings or a defective tap changer. The Turns Ratio Test (TTR) will detect and confirm a difference in voltages between phases. This means, that your transformer is not operating up to the manufacturer’s specifications and is not producing proper output voltages. This is also an early indication of transformer failure. It can also be used for transformer acceptance testing when a new transformer is installed. This will also be a base line for future diagnostics.

Insulation Power Factor

Better known as the “DOBLE Test”, IPF or insulation power factor test is the most comprehensive measurement of insulating properties of a power transformer or any apparatus with a winding.  Elements such as deterioration, contamination, moisture, and heat can breakdown dielectric strength.  Insulation Power Factor Testing measures the dielectric losses due to leakage current thru the insulation.

Insulation Resistance

The insulation resistance test is a direct current evaluation test of the insulation and gives a reliable indication of the presence of moisture, contamination, or breakdown in the insulation. This test also establishes a benchmark for future comparative tests.

Transformer Turns Ratio

The insulation resistance test is a direct current evaluation test of the insulation and gives a reliable indication of the presence of moisture, contamination, or breakdown in the insulation. This test also establishes a benchmark for future comparative tests.

Winding Resistance

Winding Resistance Test determines the I2R losses in the transformer, and as a benchmark for assessing possible damages in the field.  As a  routine test procedure, this procedure is used to determine abnormalities due to loose connections, broken strands of conductors, high contact resistance in tap changers, high voltage leads, and bushings.

Potential Transformer Off-line

Power Cable Testing

Acoustic Pinpointing

Cable diagnostics and pre-location can provide invaluable data for directly buried cables.  Acoustic pinpointing is possible thru the use of a surge generator and a “ground” microphone pinpointing device to show the exact location of the fault.

Cable Diagnostics

Upon completion of an insulation resistance test, we can determine and clasify the type of insulation fault a cable has.  If the insulation resistance measurement falls below 100Ω, this is considered a low ohmic resistance fault that can be located by the use of a Time Domain Reflectometer, however if the fault that exists is beyond 100Ω, the fault must then be converted to a low ohmic resistance fault by process of permanent burning, impluse current, or voltage decay.

Insulation Resistance

The insulation resistance test is a direct current evaluation test of the insulation and gives a reliable indication of the presence of moisture, contamination, or breakdown in the insulation. This test also establishes a benchmark for future comparative tests.

Partial Discharge

PD defined is a localized dielectric breakdown within a small portion of an electrical insulation system under stress of high voltage, which does not bridge the space between two conductors.  Partial Discharge is not yet a complete failure of the insulation, however, it is an indication of what is to come.  PD testing determines the presence, and locates PD activity within a system.

Power Circuit Breaker Testing

Insulation Power Factor

Better known as the “DOBLE Test”, IPF or insulation power factor test is the most comprehensive measurement of insulating properties of a power transformer or any apparatus with a winding.  Elements such as deterioration, contamination, moisture, and heat can breakdown dielectric strength.  Insulation Power Factor Testing measures the dielectric losses due to leakage current thru the insulation.

Insulation Resistance

The insulation resistance test is a direct current evaluation test of the insulation and gives a reliable indication of the presence of moisture, contamination, or breakdown in the insulation. This test also establishes a benchmark for future comparative tests.

Partial Discharge

PAD defined is a localized dielectric breakdown within a small portion of an electrical insulation system under stress of high voltage, which does not bridge the space between two conductors.  Partial Discharge is not yet a complete failure of the insulation, however, it is an indication of what is to come.  PD testing determines the presence, and locates PD activity within a system.

Power Quality Analysis

Protective Relays

Rotor

Station Ground Testing

Supply of Power System Software (SKM)

Surge Arrester Testing

Testing and Calibration

Transformers

Dissolved Gas Analysis

The DGA is one of the easiest, most convenient test that can be performed on a power transformer, yet it is one of the most important.  DGA determines the health of a transformer’s insulating oil.

 

Partial Discharge

PD defined is a localized dielectric breakdown within a small portion of an electrical insulation system under stress of high voltage, which does not bridge the space between two conductors.  Partial Discharge is not yet a complete failure of the insulation, however, it is an indication of what is to come.  PD testing determines the presence, and locates PD activity within a system.

Dissolved Gas Analysis

The DGA is one of the easiest, most convenient test that can be performed on a power transformer, yet it is one of the most important.  DGA determines the health of a transformer’s insulating oil.

Exciting Current Test

Typically part of preventive maintenance test procedures, the exciting current test is also performed during commissioning, acceptance, and after fault/trip.  The Exciting Current Test provides information and measurement on abnormal core grounds, winding faults (shorts and open circuits), manufacturing defects, and load tap changer problems.

Insulation Power Factor

Better known as the “DOBLE Test”, IPF or insulation power factor test is the most comprehensive measurement of insulating properties of a power transformer.  Elements such as deterioration, contamination, moisture, and heat can breakdown dielectric strength.  Insulation Power Factor Testing measures the dielectric losses due to leakage current thru the insulation

Insulation Resistance

The insulation resistance test is a direct current evaluation test of the insulation and gives a reliable indication of the presence of moisture, contamination, or breakdown in the insulation. This test also establishes a benchmark for future comparative tests.

Leakage Reactance

Also know as the Short Circuit Impedance Test,  is a procedure that can be performed on a per-phase basis.  This test can confirm Nameplate Impedance data, and detect winding deformation.

Partial Discharge

PD defined is a localized dielectric breakdown within a small portion of an electrical insulation system under stress of high voltage, which does not bridge the space between two conductors.  Partial Discharge is not yet a complete failure of the insulation, however, it is an indication of what is to come.  PD testing determines the presence, and locates PD activity within a system.

SFRA

Sweep Frequency Response Analysis is a powerful method to measure and evaluate the mechanical integrity of a power transformer’s core, winding, and clamping structures by measuring their electrical transfer functions over a wide frequency range.

Transformers Turn Ratio

This test can detect shorted turns in the windings or a defective tap changer. The Turns Ratio Test (TTR) will detect and confirm a difference in voltages between phases. This means, that your transformer is not operating up to the manufacturer’s specifications and is not producing proper output voltages. This is also an early indication of transformer failure. It can also be used for transformer acceptance testing when a new transformer is installed. This will also be a base line for future diagnostics.

Winding Resistance

Winding Resistance Test determines the I2R losses in the transformer, and as a benchmark for assessing possible damages in the field.  As a  routine test procedure, this procedure is used to determine abnormalities due to loose connections, broken strands of conductors, high contact resistance in tap changers, high voltage leads, and bushings.

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