Capacitors to the rescue

[K6JEK]

Here's an article about capacitor banks increasing the handling capacity of power transmission lines in New York state. Any power systems engineers out there who can explain this? Is it really all about line losses due to inductive reactance?

http://www.greentechmedia.com/articles/read/new-york-brings-renewables-downstate-without-new-power-lines

[DMOD]

It's all about increasing the Power Factor:

http://www.allaboutcircuits.com/textbook/alternating-current/chpt-11/calculating-power-factor/

Phil - AC0OB

[KC4VWU]

The power companies CAN'T lose any money! However, once it's past your meter, feel free to use as much imaginary power as you like!

[K6JEK]

It's all about increasing the Power Factor:

http://www.allaboutcircuits.com/textbook/alternating-current/chpt-11/calculating-power-factor/

Phil - AC0OB

But of course! Thanks for shaking the rocks out of my head.

[W3RSW]

Imaginary power will save your delicates from your motors. 

[Opcom]

The simple and plain truth of power factor and generation.

http://bunkerofdoom.com/travel/steelsoldiers4/20080924_2200_Bagnell_dam/tour/100_6795.JPG

[K6JEK]

The simple and plain truth of power factor and generation.

http://bunkerofdoom.com/travel/steelsoldiers4/20080924_2200_Bagnell_dam/tour/100_6795.JPG

Great picture EXC AMPS and EXC VOLTS. Are what?

[KD6VXI]

Excitation.

Have to have some power in the field to start production.

--Shane
KD6VXI

[W7TFO]

I have one like those shown here, the dang thing is water cooled...

73DG

[WA2TTP Steve]

This is my 2 cents on reactive compensation and power factor based on my 29 years in power system operations in New York.

Reactive compensation is all about reducing system losses and maintaining an acceptable voltage profile across the power grid. Compensation is done starting at the distribution level, 13.8kv, with capacitor banks mounted on poles out where the customer load is connected. These are configured as fixed caps, others can be on time clocks and lastly radio remote control caps that are placed in service as needed under the direction of the system operators.

As the load and power flow across the system increases on a typical day additional large capacitor banks will be switched in directly on the transmission system starting at 69kv all the way up to 345K. The reason we need capacitive compensation is because much of the system load tends be inductive, lots of motors etc, or lagging power factor which tends to cause the system voltage to decrease. Also transmission lines become inductive as they are loaded up beyond the surge impedance loading and system transformers are an inductive load also. In the NYISO control room where I worked we would monitor the system voltage, the reactive loading on the generators and tie lines and switch in capacitor banks as needed to minimize the reactive loading on generators and maintain system voltage within our operating limits. In the summer time, our peak season, we would eventually have all the capacitor banks in service and at that point the generators would have to start carrying more and more reactive to maintain the voltage levels on the system. At very high reactive levels the generators could heat up enough to have to reduce their megawatt output to be able to support the system voltage.

The Marcy South series compensator mentioned in the link is a way to make the transmission line self-compensating at higher loading therefore taking some of burden off the generators for reactive support. This reduces system losses and helps with voltage support.

Hope this helps answer the question.

Steve
Retired Shift Supervisor at the NYISO.

[K6JEK]

Thanks Steve for your explanation.