Distribution Line Failures, Loads and Maintenance Procedures

Distribution Line Failures and Maintenance

Breaking load: Load that causes failure of any part of the support.

Effort: This is the maximum mechanical stress applied to a support. This mechanical stress, multiplied by the factor of safety, must be supported by the support.

Nominal effort (E): Horizontal stress available at a distance h from the top of the head, in the principal direction.

Secondary effort (S): Horizontal stress found at height h, considered equal in magnitude to the nominal effort. En (torque) = Et: the available horizontal stress at the end of a crossarm placed at a distance h from the top of the head, and at a distance d from the center of support; it tends to rotate the support about its vertical axis.

Secondary effort (S): Horizontal stress found at height h, considered equal in magnitude to the nominal effort. En (torque) = Et: the available horizontal stress at the end of a crossarm placed at a distance h from the top of the head, and at a distance d from the center of support; it tends to rotate the support about its vertical axis.

2.6 - Common Failures in Distribution Lines

The most common breakdowns that often occur in distribution lines include:

Causes such as falling trees or branches, strong winds, lightning, etc., typically produce the following damages to distribution lines:

• Wire breakage
• Phase-to-phase or phase-to-ground faults (cross between phase conductors or grounded download)
• Insulator breakage; breakage or collapse of support
• Rupture of switchgear and other third-party damage caused by these incidents or breakdowns

8 - Interruption Types by Duration

Depending on the type of failure and the response time of the protective elements, interruptions are classified as follows:

• Micro-cuts: interruption lasting less than one second, when the transient fault disappears after the first automatic reclosure.
• Brief interruption: interruption lasting less than one minute, during which the semi-permanent fault disappears after the second automatic reclosure.
• Interruption: stoppage longer than one minute, during which the semi-permanent or permanent fault requires repair.

2.7 - Disclaimers and Maintenance Work

To perform work on a distribution line—either to repair a fault, to connect new equipment, to carry out alterations, or to perform routine maintenance—we follow a predetermined procedure under the rules of the "Five Golden Rules". These rules are applied to ensure safety and proper operation during maintenance and fault-repair activities.