Tan-delta

Tan-Delta and Capacitance Measurement

Tan Delta measurement is an advanced and reliable non-invasive diagnostic test to assess the insulation quality and concerns in electrical systems.

What is Tan Delta?

Tan delta is one of the most reliable diagnostic tests for detecting insulation defects in electrical systems. The longevity of high-voltage equipment greatly depends on the reliability of its insulation system. Tan Delta provides a detailed picture of the condition of these insulation systems, enabling timely action and avoiding unplanned downtime.
diagram

Fig.1.Current(I) v/s Voltage(U) Phase Diagram

At assetconditionmonitoring.com, we analyse each system's performance and conduct TD testing with advanced tools to assess the condition of high-voltage insulation accurately. In transformers, power cables, motors, and switchgear, insulation serves as a protective barrier. Unfortunately, it can degrade over time, resulting in unexpected failures and hazards. With our advanced Tan Delta testing, early detection of insulation deterioration can be hassle-free, avoiding costly interruptions and prolonging the lifespan of the equipment.

Why Tan Delta Testing is done?

Tan Delta Testing is pivotal for finding insulation faults in high-volt assets like cables, transformers, and bushings. The loss angle (δ), measured in a tan delta test, represents the phase difference between the ideal capacitive current (IC) and the total leakage current (IL).A larger δ means more resistive losses, indicating the insulation is no longer performing like a pure capacitor. Tan Delta Testing is performed for several key benefits, including:

Early fault Detection

TD testing detects moisture content, any contamination, and insulation wear early, before any failure sets in.

Non-destructive testing

TD testing is generally done at lower frequencies and controlled coltages to prevent equipment damage.

Trend Analysis

Tan Delta testing gives deterioration patterns when testing the results at normal and elevated voltages.

Enhances System Reliability

Cost Savings

Tan Delta Testing aids in planning maintenance schedules and avoiding unplanned outages.

Extended asset life

TD testing ensures safe operating conditions for heavy-volt assets and extends the asset life.

Improved precision

TD testing picks up the slightest changes in insulation properties and gives improved protection and precision.

Process of Tan Delta Testing

Tan Delta testing is a reliable diagnostic method that must be carried out with precision, calibrated equipment, and strict adherence to international testing standards to ensure accurate results and maintain insulation health. The following are the processes involved in the Tan Delta Test:

01

Preparation of Equipment

Before the insulation is assessed, the cable, potential transformer, bushings, current transformer, and winding are properly disconnected from the rest of the system.

02

Apply Test Voltage

Start the evaluation using the lowest frequency level of test voltage on the equipment whose insulation is being assessed.

03

Initial measurement at normal Voltage

Set the equipment to its specified operating voltage. Capture the tan delta readings at this voltage using the tan delta controller. This will act as the initial reference measurement.

04

Increase to High Voltage

Increase the voltage applied between 1.5 and 2 times the typical operating voltage to evaluate the insulation being tested.

05

Data comparison and Analysis

Use a loss angle analyzer to check the tan delta values from the normal voltage test (Step 3) against those from the high voltage test (Step 5). If the values remain steady, the insulation is likely in good shape. However, if the values go up significantly at higher voltage, it may indicate that the insulation is deteriorating.

How do we do Tan Delta Testing?

At Assetconditionmonitoring.com, we offer expert Tan Delta Testing services, ensuring complete insulation health assessments that help the reliability and efficiency of high-voltage assets. We employ advanced technology combining expert analysis and risk-based knowledge to identify early signs of wear, aging, and contamination. We ensure reliable results, minimal downtime, and aid in asset optimisation.

Why Choose Us?

  • Expert Testing Team
  • Advanced Diagnostic Tools
  • International Standards Compliance
  • Accurate and Reliable Results
  • Actionable Maintenance Insights
  • Proven Industry Trust
Protect your assets and get accurate tan delta diagnostics with assetconditionmonitoring.com expert services

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Frequently Asked Questions

What does a Tan Delta test reveal?

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A Tan Delta test reflects the health of electrical insulation by comparing the leakage current against the ideal capacitive current.

How is Tan Delta testing different from Hipot testing?

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Hipot testing provides a simple pass/fail result to verify whether insulation can withstand a high voltage. In contrast, Tan Delta testing evaluates insulation performance in detail, including aging, deterioration, and moisture presence.

How is Tan Delta measured?

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Tan Delta is measured by applying a controlled voltage to the insulation using dedicated test instruments and recording the dissipation factor, also known as the loss angle.

How are Tan Delta results interpreted?

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Stable Tan Delta readings across different test voltages indicate sound insulation. Increasing values with rising voltage suggest insulation deterioration, moisture ingress, or contamination.