Galloping of conductors is where conductors oscillate in large, low-frequency movements caused by wind and ice conditions. Unlike smaller vibrations, galloping involves dramatic swaying motions that can span several meters in amplitude. Galloping poses serious risks to power infrastructure in the form of conductor clashing and equipment failure. Modeling of this behavior is done by calculating the swept area, or ellipse, that a galloping conductor occupies. Ellipses can then be analyzed to determine if there are clearance violations, such as ellipses intersection or overlap.

Neara allows users to complete galloping analysis to assess the ellipses created by conductors as well as clearance violations between ellipses including ellipse overlap. The set up for this has some complexity so a Module has been created to improve simplicity and allow users to conduct analysis quickly and simply.

Using the module allows users to interact with galloping via a purpose built panel and two reports.

Galloping assessments are completed using Finite Element Analysis (FEA). For more information about FEA, see Finite Element Analysis.

There are a few set up steps that need to be completed as follows.

The module title will appear in the sidebar and once selected the details including Key and Namespace will be displayed.

Galloping must complete a sag calculation and a blowout calculation. In order to do this, two environments must be established in the Environments menu:

For example:

For more information about Environments, see Modify an Environment.

Note: Environment names and descriptions do not have to conform to the above. It is recommended these are unique and easy to understand as users will need to configure which environment the galloping assessment should use for the sag calculation and which for the blowout calculation.

To open the galloping user panel select (+) from any section on the workspace and then select gallop~Galloping User Panel from the User Panels section of the menu.

The panel contains 3 main sections:

If fields have not been configured satisfactorily warnings will appear, including if a blowout environment does not have any wind applied.

This provides an overview of the report results. For more detail, refer to the reports.

Open galloping reports from the user panel using the links.

Galloping overview provides a row per span stack and advises:

Galloping breakdown provides a row per conductor and advises:

Clearance Visualization provides a row per span stack and advises:

Ellipse geometry is defined by the following parameters.

Users can now select from three galloping ellipse calculation methodologies via the Galloping UI.

Note: the Cigre methodology contains two variations, bundled and unbundled. The appropriate methodology will be automatically applied based on whether the conductors under assessment are bundled or unbundled.

There are two variations for this methodology based on whether the conductors are bundled or unbundled.

Note: this method will produce an error for spans with very small sag values as the large denominator coefficient yields a near-zero argument for the ln() function, preventing a valid result. The error will advise the current sag value as well as the minimum sag required to remove the error.

There are two main functions used to establish galloping, each taking a number of arguments.

calculate_gallop(strain_section: …, blowout_catenary: …, sag_catenary: …, method: …)

calculate_gallop_clearance(gallopingEllipses)

The galloping functions require a range of fields and collections to be established and then configured. This is not a simple process so the module has been established to make it easier for users to use the galloping capability without having to complete complex set up.

The set up contained in the module is as follows with many fields utilizing _a and _b variants to return separate results based on the selected perpendicular wind direction:

For Cigre method, if the cells in the Galloping Breakdown report relating to bundled conductors are empty, the sag may be too small which means the calculation is invalid and will not return a value.