Power Bytes

Voltage: High or Low, Which Way to Go?

July 01, 2021 Caterpillar Inc. Season 2 Episode 8
Power Bytes
Voltage: High or Low, Which Way to Go?
Show Notes Transcript

Today I'm joined by Eric Bibby and we are going to discuss Low vs High Voltage generators.  We'll talk about the differences as well as an important tip to getting help with the analysis.

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Lou:  Good Day and welcome everyone to Power Bytes!  I am your host Lou Signorelli  and Power Bytes is your destination Podcast for power generation conversation.  As always please know how much we appreciate you, our listeners.  We hope you find our topics helpful and interesting.  There are several ways for you to get in touch with the show. You can send us an email at powerbytes@cat.com, visit us at Cat Electric Power on Facebook or LinkedIn.  If you enjoy your time with us today Please remember to subscribe to our podcast.
  
Lou:  I'm joined today by Eric Bibby, the author of the white paper with me.   Eric is an Electrical Engineer from Purdue and has been at Cat for 13 years.  Eric has held positions ranging from Application and Product development to supporting our dealers currently in the SE portion of the United States.

Welcome Eric and thanks for joining us today. 
  
Lou: First let’s start with a little “generator voltage” basics.  What is low vs high voltage?   
  
Eric: Good question, depends on who you ask.  In the Caterpillar genset world up to around 5MW, we typically look at 1kV or less as LV and from1kV and up to 15kV as HV.  Occasionally, we’ll refer to the low end of the HV range as MV, but essentially our products fall into one of the two categories.  
 
Lou: It seems that the generator industry has unique terminology that is different from say the utility industry? 
 
Eric: Very true.  Our CAT teams located in the distribution and utility space look at things a little differently.  For example, our SWGR group would look at anything below 5kV as LV and up to 15kV as medium.   Then if you look at our turbine business which lives in the utility space, you’ll find voltages ranging from 33kV to 66kV or even all the way up to 110kV in the high overhead transmission lines.
 
Lou: Now that we have an idea of the difference, how would this affect the generator?  What are the specific differences between LV and High? 
 
Eric:  If the power remains the same then the lower the voltage the higher the current.  With more current you will need more or larger cables to get the energy out of the generator and ultimately to the load.  This may mean added cost especially if there is significant distance between the genset and the facility loads.  However, the upfront cost for the LV generator is significantly less than that of a HV and generally there are shorter lead times on LV machines as they are typically easier to manufacture. 
 
Lou: Sounds like there are some very practical differences based on the applications.  Long runs to the load and/or the desire to transmit lower current would necessitate a HV generator, while say a distributed design located closer to the load would dictate the use of a LV generator.  Did I miss anything in that breakdown? 
 
Eric: No, like most things it is going to be application and design dependent.  For example power houses paralleling multiple gensets together, would necessitate the utilization of HV generators to keep the transmission lines to a reasonable size.  However, if a single genset design is being utilized or one with multiple gensets powering separate power paths close to the load in a distributed scheme, then the reduced capital cost of the generators would more than cover the increase costs in power distribution.
 
Q5: Thanks for clarifying that.  Sounds like a lot goes into the decision.  In the end It is most certainly a good idea to work with someone with in-depth system design experience.   Can you summarize what our listeners should take away as a quick lesson on the two types of generators? 
 
Eric:   The most important thing is to look at the big picture.  Try to resist getting tunnel vision and only focusing on a single component instead of looking at the system overall.  Know the site limitations.  Are you able to locate the gensets close to the load or does the design dictate multiple paralleled generators located in a powerhouse some distance from the facility and downstream loads?  What does the desired distribution scheme look like?  Asking these important questions up front can set you on the path to finding the best fit for your specific application.  Finally, don’t be afraid to ask for help.  Caterpillar has a wide range of resources at your fingertips to aid in the decision-making process, use them.  We’re here to help.  
 
Lou: Thanks Eric!  So the summary in this space is that the Cat Dealer and Cat Engineering can be of  significant importance in the design process which translates  to  more efficient systems with an eye to cost effectiveness? 

Eric: Absolutely.  It's an increasingly competitive market and looking at the entire project is the most effective way to compete.

Lou: There you have it folks.  I'd like to thank Eric Bibby for sharing his insights with us today… and thank you, our listeners for listening to Power Bytes. 
If you’d like to suggest other topics for the program or have some feedback to share,  please write us here at powerbytes@cat.com or visit Cat Electric Power on Facebook or LinkedIn.   Please remember to subscribe to our Podcast wherever  you listen to your favorite podcasts.  Till next time, thanks for listening to Power Bytes and have a great day!