To determine the minimum approach distance for work near a 220kV power line, you must consult the relevant safety regulations and guidelines [1]. These regulations typically specify minimum clearance distances based on voltage levels to prevent electrical contact and ensure worker safety [2].

Here's a general approach to determine the minimum approach distance:

1. Identify the applicable regulations: Check your local or national occupational safety and health regulations for specific requirements related to high voltage power lines [1].
2. Determine the voltage: Ensure you know the accurate voltage of the power line in question (220kV in this case) [1].
3. Calculate the minimum approach distance: Use the formula or table provided in the regulations to calculate the minimum approach distance. A common formula is: Minimum clearance (in feet) = 10 feet + 0.4 inches for each 1 kV over 50 kV [1]. However, this can vary, so refer to the specific regulations in your jurisdiction [2].
4. Consider additional factors: Be aware that certain conditions might require increasing the minimum approach distance. These include atmospheric conditions, altitude, and the presence of broken insulators 3, 18.
5. Implement safety measures: If work needs to be performed closer than the calculated minimum approach distance, you must implement additional safety measures such as de-energizing and grounding the power line, using insulating barriers, or ensuring workers are qualified and using appropriate personal protective equipment 1, 13.

Always prioritize de-energizing the power line whenever possible [3]. If that's not feasible, consult with the utility owner/operator or a qualified engineer to determine the safest approach and minimum clearance distance [2]. Ensure all workers are adequately trained and aware of the hazards and safety procedures [1].