Insulation Coordination Study

Lightening strikes, frequent switching, occurrence of faults, and resonance causes electrical transients in the power system. Transients over voltages are sudden and short-lived increases in voltage which can cause disruption and damage to the insulation of the equipment installed.

An insulation coordination study is a type of analysis that aims to determine the optimal insulation levels for different equipment and components in an electric power system. Insulation coordination studies help design systems that can handle these transient events without suffering breakdowns. This minimizes the risk of system failures caused by insulation breakdown which can lead to costly outages and downtime.

Why perform Insulation Coordination Study?

The main objective of the Insulation Coordination Study is to provide necessary safety and code recommendations to the facility owners, EEORs and gear manufacturers about optimal insulation levels for critical components in the power system. It ensures that insulation levels of various power system components are appropriately coordinated to protect against over voltages, preventing insulation breakdown and equipment damage.

Verify and validate the results of the study, such as the insulation margins, the overvoltage levels, the protection performance, etc. This can be done by using the sensitivity analysis, the uncertainty analysis, or the field tests. Insulation coordination studies are governed by various engineering Codes and Standards some of them are as follows:

• IEEE Standard 1313-IEEE Guide for Insulation Coordination- Provides guidance on the selection of insulation levels and coordination of insulation strength for equipment within power systems.
• IEC 60071 series-Insulation Co-ordination - A series of International Electrotechnical Commission (IEC) standards that provide guidance on insulation coordination for power systems.
• IEEE Standard 1243-IEEE Guide for Improving the Lightning Performance of Transmission Lines - Offers guidelines for the insulation coordination of transmission lines, especially focusing on lightning performance.
• IEEE Standard 1762-IEEE Guide for the Determination of Maximum Electric Field Stress in Insulation- Provide guidelines for determining the maximum electric field stress in insulation, aiding in insulation coordination.
• IEEE Standard 1427-IEEE Guide for Recommended Electrical Clearances and Insulation Levels in Air Insulated Electrical Power Substations- Provides recommendations for electrical clearances and insulation levels in air-insulated power substations.

Producing Insulation Coordination Results and Identifying Issues

An Insulation Coordination analysis is performed to check and improve the insulation systems to prevent from any damage. It consists of multiple steps that help evaluate and optimize the insulation performance under different operating conditions Following are the steps to perform insulation coordination study:

• Define the scope and objectives of the study, such as the system configuration, voltage levels, equipment ratings, design criteria, etc.
• Identify and model the sources and characteristics of the transient over voltages that can occur in the system, such as lightning, switching, faults, resonance, etc. This can be done by using analytical methods, simulation tools, or field measurements.
• Determine the insulation withstand levels of the equipment and components in the system, such as the basic insulation level (BIL), the switching impulse withstand level (SIWL), the lightning impulse withstand level (LIWL), etc. This can be done by using the manufacturer’s data, the codes and standards, or the test results.
• Select and coordinate the insulation and protection devices for the system, such as surge arresters, circuit breakers, relays, etc. This can be done by using the insulation coordination principles and rules, the codes and standards, or the optimization techniques.

Qualified PEs and EITs/Professional Engineers:

Providing engineering recommendations about the causes of exceptions, the integrity of the system, or recommendations for corrective actions requires knowledge and skills beyond those of power systems engineering. Our team of certified professional engineers have the expertise to investigate optimal/abnormal scenarios and provide innovative engineering solutions for your power system. We work closely with our clients to accurately model, test, validate, and recommend optimal solutions for industrial & commercial facilities.

AllumiaX, LLC provides independent consulting and third-party engineering support by presenting comprehensive deliverable reports backed by the latest industry standards and best practices. Analysis is performed based on industry-leading software: SKM, ETAP, PS CAD, EMTP and Easy Power and proven results based on accurate modelling and calculations. The reports are expected to include the following deliverables:

• A comprehensive and accurate electrical model of the facility
• Complete voltage profiles for the power system including over/under voltage critical points and equipment susceptible to over voltages.
• Insulation levels for each piece of equipment including transformers, circuit breakers, cables, and surge arresters.
• Recommendations for surge arrester types, ratings and placement to effectively mitigate overvoltage.
• Identify safety margins and coordination points to ensure robust insulation coordination under different scenarios.
• Factors applied to insulation levels to account for uncertainties, environmental conditions, and equipment aging.
• Recommendations for optimizing insulation coordination to achieve a balance between reliability and cost-effectiveness.
• Solutions for optimal power flow throughout the network.

What is the customer/client responsible for?

At AllumiaX, we evaluate the potential risks and severity in case of an over and undervoltage condition and recommend the best-in-the-market practices to our customers for a safe, regulated, reliable, and well-designed power system. A customer who chooses not to perform Insulation Coordination Study misses out on a huge value proposition.

Customers should help develop a list of equipment to be evaluated via onsite data collection for the existing facility or by providing updated one-line, BOMs and cutsheets for all equipment in the facility.

What to Expect?

Insulation Coordination Studies will be in 100% compliance with the latest industry standards. Study outcomes and recommendations are expected to improve the following areas of your facility:

• Increase reliability of the power system by minimizing the damage and disruption caused by transient over voltages.
• Enhancements to the facility through adjustments in system voltage levels and conductor sizes.
• Ensuring Codes and Standards compliance.
• Overall safety and operation costs are expected to decrease.
• Performance and compatibility of the components increase.