Questions and Answers
What percentage of PSO distribution lines are below grade within the city limits?
Where are most of the below-grade PSO distribution lines located?
What is the maximum voltage that PSO distribution lines can carry?
Which materials are used for PSO distribution wires?
Signup and view all the answers
What is the purpose of the coating on PSO distribution wires?
Signup and view all the answers
What is the maximum voltage that transmission lines can carry in Tulsa?
Signup and view all the answers
How many insulators do transmission lines in Tulsa usually have at a minimum?
Signup and view all the answers
Where are transmission lines generally supported?
Signup and view all the answers
What happens to the voltage at substations in Tulsa?
Signup and view all the answers
What is a notable characteristic of substations?
Signup and view all the answers
What is the primary function of transformers?
Signup and view all the answers
Which type of transformer is often located in vaults?
Signup and view all the answers
What is a significant hazard for responders when dealing with vaults?
Signup and view all the answers
What is TFD personnel's protocol when dealing with fires in underground vaults?
Signup and view all the answers
Apart from aerial, what other types of transformers are mentioned?
Signup and view all the answers
What is the final part of the electrical distribution system?
Signup and view all the answers
What type of wiring is most commonly used for service wires entering a residential structure?
Signup and view all the answers
What occurs when current runs to ground at the point of contact of a downed, energized wire?
Signup and view all the answers
What is 'step potential'?
Signup and view all the answers
What should responders do if they find themselves experiencing step potential?
Signup and view all the answers
Study Notes
Tulsa's Electrical System
- Transmission lines carry electricity up to 345,000 volts and are supported by towers or poles.
- These lines typically take electricity from generation sites to substations, and can be found within the city limits.
- Transmission lines can be identified by the number of insulators, typically at least six.
Substations
- Substations are fenced-in areas where the voltage is reduced and sent into the distribution part of the system.
Distribution Lines
- Within the city limits, PSO has approximately 35% of their distribution lines below grade, mainly in new residential neighborhoods and apartment complexes.
- Distribution lines carry up to 34,500 volts, are copper, aluminum, or aluminum-coated steel wires, and can be single strand or stranded.
- Wires are often coated with a material that protects against wear, chaffing, and corrosion, but is not insulation.
Transformers
- Transformers can be aerial, pad-mounted, or sub-surface, and are designed to reduce voltage to a more usable level for customers.
- Sub-surface transformers are often located in vaults, which are confined spaces that present significant hazards to responders.
- TFD personnel will not enter or attempt to fight fires in underground vaults without PSO on scene.
Service Connections
- The final part of the distribution system is the service connection, which delivers power to the customer through wires entering the structure through the weatherhead or a conduit.
- The most common service wires entering a residential structure are triplex wiring, including two wires carrying 120 volts each, and one neutral.
Electrical Hazards
- When a downed, energized wire is in contact with the earth, there is current running to ground at the point of contact, creating a gradient, or decreasing current, that spreads out concentrically.
- This energized field can extend for several feet from the point of contact, creating the possibility of step potential.
Step Potential
- Step potential occurs when responders create a circuit with their feet as they walk near a downed wire, creating a path or circuit that can cause current or shock.
- Tingling sensations in the lower extremities have been reported at lower voltages, and death or serious injury can result at higher voltages.
- To avoid step potential, responders should bring both feet together and hop away from the downed wire location.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers electrical system response for the Tulsa Fire Department, specifically transmission lines and substations. Learn about electrical systems and emergency response strategies.