Pole loading analysis: What is it, and why is it important?

What is Pole Loading Analysis?

Pole loading analysis (PLA) is a measure of pole condition. It involves understanding, analyzing, and accounting for the forces that affect utility poles—such as equipment weight, the size, strength, and material of the pole, and environmental conditions. PLA prevents overloading, which can lead to failure.

Initial pole loading guidelines established by the electric utility engineering team ensures that a pole, when initially put into service, has sufficient strength to support the applied load. Over time, more load is often applied to the structure as third-parties request to attach to the pole – for example, a communication company adding new fiber or a wireless company adding small cell antennas.

PLA also ensures that poles comply with the National Electric Safety Code (NESC) requirements. The Code sets the bar for mitigating environmental factors and provides the baseline for safety. Performing PLA using NESC load cases will provide an idea about the percent loading on the pole. Poles with utilization percentages at or above 100% do not meet NESC minimum requirements. Therefore, these poles should be replaced, re-enforced, or re-engineered. For example, if a pole is loaded to 110% capacity, the pole may not withstand extreme climatic conditions and could fail.

Why is Pole Loading Analysis Important?

Pole Loading Analysis is a critical component in determining a network’s resiliency and combating the damaging effects of nature. PLA can prevent the failure of poles while also saving pole owners a potential lawsuit.

How to Conduct Pole Loading Analysis:

1) Data Collection

Pole owners or their certified contractors visit the pole to collect data physically. The data includes information about pole properties, type and size of equipment, line angle for the wires, attachment heights, and pole condition.

• The IKE Device is among the most efficient tools for capturing accurate pole data.

2) Analysis

Once the information is collected in the field, a back-office engineer performs PLA to evaluate the pole’s loading to capacity ratio. The first step is calculating the vertical and horizontal loads on the pole caused by the weight of transformers, conductors, and other equipment. This data is then used to understand stresses on the pole, such as the shear force and bending moment. Next, the engineer factors in natural forces acting on the pole, such as wind, ice, and temperature changes and calculates loading capacity. A traditional loading capacity is the ratio of the applied load to the pole strength for a given load case (specific wind speed, ice, and temperature). This ratio gives an idea of any excess strength capacity on the pole and determines if it complies with NESC requirements.

There are a number of PLA software options available designed to reduce the human effort involved by enabling users to quickly build a model of poles as they exist in the field and determining if NESC standards are met. In addition, users can quickly alter attachment heights, line angles, model new equipment additions or changes in weather patterns, and re-analyze loading for a high number of poles in a short period.

• IKE PoleForeman is the most trusted PLA software used by electric utilities.

3) Mitigation

PLA results surface issues and help prioritize system improvements, such as replacing or retrofitting an existing pole. Knowledge of weak points on the grid allows utilities to identify the possible failure points in an outage event and allocate resources to mitigate the hazard.

• The IKE Device is among the most efficient tools for capturing accurate pole data.

How IKE Can Help

Used by some of the largest electric utilities in the country, IKE PoleForeman has been a trusted partner in creating system resilience for more than 20 years. It fully integrates with IKE Office Pro, enabling high volumes of poles to be imported for fast PLA. Additionally, users can export PLA data into the formats and systems most commonly used across the industry.

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