- #1
sirsajid
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What are the disadvantages of having low power factor?
What are the disadvantages of having low power factor?
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Discussion Overview
The discussion centers around the disadvantages of having a low power factor, particularly in the context of electrical systems and utility billing. Participants explore the implications of low power factors on generation and transmission costs, as well as the operational aspects of switchgear and circuit breakers.
Discussion Character
- Technical explanation
- Conceptual clarification
- Homework-related
- Debate/contested
Main Points Raised
- Some participants note that a low power factor requires utilities to generate more volt-amperes than the minimum necessary to supply real power, which can increase costs.
- It is mentioned that with a power factor of 0.7, the apparent power would be 1.4 times the real power, leading to increased line current and doubled losses in the circuit.
- Participants discuss that components such as generators, conductors, transformers, and switchgear may need to be larger and more expensive to accommodate the extra current due to low power factors.
- One participant seeks clarification on the difference between switchgear and circuit breakers, leading to a discussion about their functions in electrical systems.
- There is a request for further homework questions, which prompts a reminder that homework is not allowed in the forum.
Areas of Agreement / Disagreement
Participants generally agree on the negative implications of low power factors on costs and system requirements, but there is no consensus on the appropriateness of homework questions in the forum.
Contextual Notes
Some statements rely on assumptions about the relationship between power factor and system costs, and the discussion does not resolve the complexities of these relationships or the specific voltage levels in generation and transmission stages.
Who May Find This Useful
This discussion may be useful for those interested in electrical engineering, power systems, and the economic implications of power factor in utility management.
- #2
vk6kro
Science Advisor
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This is from the excellent article in Wikipedia about Power Factor:
The significance of power factor lies in the fact that utility companies supply customers with volt-amperes, but bill them for watts.
Power factors below 1.0 require a utility to generate more than the minimum volt-amperes necessary to supply the real power (watts).
This increases generation and transmission costs. For example, if the load power factor were as low as 0.7, the apparent power would be 1.4 times the real power used by the load.
Line current in the circuit would also be 1.4 times the current required at 1.0 power factor, so the losses in the circuit would be doubled (since they are proportional to the square of the current).
Alternatively all components of the system such as generators, conductors, transformers, and switchgear would be increased in size (and cost) to carry the extra current.
You can read the rest of it here:
http://en.wikipedia.org/wiki/Power_factor
The significance of power factor lies in the fact that utility companies supply customers with volt-amperes, but bill them for watts.
Power factors below 1.0 require a utility to generate more than the minimum volt-amperes necessary to supply the real power (watts).
This increases generation and transmission costs. For example, if the load power factor were as low as 0.7, the apparent power would be 1.4 times the real power used by the load.
Line current in the circuit would also be 1.4 times the current required at 1.0 power factor, so the losses in the circuit would be doubled (since they are proportional to the square of the current).
Alternatively all components of the system such as generators, conductors, transformers, and switchgear would be increased in size (and cost) to carry the extra current.
You can read the rest of it here:
http://en.wikipedia.org/wiki/Power_factor
- #3
sirsajid
- 13
- 0
Thank you very much for your answer. I have got it know.vk6kro said:
Could you tell me the difference between switchgear and circuit breaker?
- #4
vk6kro
Science Advisor
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Switchgear is the equipment that is used for normal operation of equipment. You turn it on. You turn it off.
Circuit breakers are for overload conditions where too much current is being drawn by a circuit and the power is removed to avoid further damage or fires.
There is some overlap in these. A circuit breaker is commonly incorporated into each power switch so that the power switch is turned off by the circuit breaker.
Circuit breakers are for overload conditions where too much current is being drawn by a circuit and the power is removed to avoid further damage or fires.
There is some overlap in these. A circuit breaker is commonly incorporated into each power switch so that the power switch is turned off by the circuit breaker.
- #5
Averagesupernova
Science Advisor
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Next homework question please!
- #6
vk6kro
Science Advisor
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Couldn't be homework, because that isn't allowed here. 
I'd rather see someone learn something than be too dogmatic about it. This one just learned about Wikipedia.
I'd rather see someone learn something than be too dogmatic about it. This one just learned about Wikipedia.
- #7
sirsajid
- 13
- 0
What is the optimum generation voltage?what are the different voltage levels from the generation to the consumer, I mean generation...transmission ...sub transmission...distribution..what are voltage levels in each stage...Averagesupernova said:
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