Insulation Coordination Studies

By: Arresterworks  09-12-2011
Keywords: Power Systems, Transmission Line

The purpose of insulation coordination is to insure that insulation used in an electrical power system is adequate for the environment in which it is applied and to understand the probability of insulation failure under transient conditions.

Substation Study

Typical studies include the analysis of a substation to determine the probability of post insulator flashovers. This is generally measured in flashovers per hundred years. Another important analysis is to determine that the insulation contained within transformers has an acceptable margin of protection. Since the internal insulation is not self-restoring a failure is completely unacceptable. An insulation coordination study of a substation will present all the probabilities and margins for all potential transients entering the station. The studies include both switching surge analysis and lightning surge analysis. Even though stations are usually shielded, the lightning surge finds its way into a substation when there is a backflash on any incoming line. The resulting current levels in the station are quite low relative to direct strikes, but all that is needed to fail insulation is voltage and not current.

Transmission Line Studies

Insulation coordination studies of a transmission lines fall into two categories. A very common study in recent times is to determine the proper locations and ratings of arrester applied on lines that do not have pre-insertion resistors installed on their breakers. A second type of study is to determine where to install arresters to reduce the back-flash-over rate of a line. This type of study also indicates what the new flashover rate will be after installation of the arresters.

Methods of Analysis and Resources

Studies completed by ArresterWorks use both time domain software (ATP) and Hileman software that accompanies the well known "Insulation Coordination of Power Systems" text by Andrew Hileman.

Numerous standards are used in analysis including IEC 60071-1 and 60071-2, along with IEEE 1313-1, 1313-2, 1243, 1410, and C62.11.

Keywords: Power Systems, Transmission Line

Other products and services from Arresterworks

09-12-2011

Training Options

Fundamentals of Arresters Protected Equipment Considerations Field Testing of Arresters Overview of Arrester Suppliers EMTP Modeling of Arresters. This Seminar is intended for Substation or Transmission Standard Engineers, Operations Personnel, Substation Packagers and Consulting Engineers. Fundamentals of Surges How to Select a TLA TLA Mechanical Considerations TLA Disposal Trends in the Industry Compact Line Considerations.


09-12-2011

Webinar

New requirements for arresters will be issues that cover testing and evaluating arrester energy handling capabilities. Thermal Energy Rating Verification Tests Sequence and Evaluation. A new edition of IEC 60099-4 and IEEE C62.11 will be published. Surge Energy Rating Verification Test Sequence and Evaluation. Any stake holder that is interested in arrester standards. 10:00 to 11:00am Eastern Standard Time on February 25th.


09-12-2011

Surge Protection Seminars

This in-depth course is designed for those responsible for the reliability of substations, distribution systems, and transmission systems. Announcing a 1.5 day Surge Protection Seminar plus a .5 day Seminar on Lightning Studies Using ATPJuly 27-28. Reliability engineers and other reliability personnel responsible for continuous improvement. Lightning is the second or third most significant cause of outages on most power systems.


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Substation Arrester Assessment Service - failure analysis

Leak checking using the appropriate method of failed and unfailed partner arresters. Close-up photography and microscopic photography to identify cause of failure. This is the most comprehensive analysis of failed arresters anywhere. Analysis of electrical characteristics of available disks. Gas analysis of unfailed partner arresters if available. In depth examination of the available parts.


09-12-2011

Substation Arrester Assessment Service - assessment

Site Visit Along with client personnel as desired by the client, each site is assessed and the following competed. Arrester Losses measured using state of the art watts loss metering. Arrester location relative to protected equipment documented. New arrester installation options analyzed.