×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

#### Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

# VAR compensator by using transmission cable

## VAR compensator by using transmission cable

(OP)
Hi guys.
I have a question correlate to VAR compensator. Can I utilize HV subsea transmission cable as static VAR compensator? This subsea cable length about 60kilo-meters.

Thanks and regards
Alfa
Replies continue below

### RE: VAR compensator by using transmission cable

I don't know the if it's relevant, but there are equivalent circuits for transmission lines that include capacitive and inductive elements. for example pi equivalent for long lines.

=====================================
(2B)+(2B)' ?

### RE: VAR compensator by using transmission cable

(OP)
Thank you electricpete..,
I think it's difficult to control or adjust a required VAR value correlate to PF rectification on the grid when we use transmission cable...cmiiw.

### RE: VAR compensator by using transmission cable

I agree. There's two problems there:

1 - there's no adjustability in the length and therefore no adjustment in equivalent circuit model

2 - the phrase reactive compensation to me implies we're talking about the fundamental so I had in mind fundamental reactive compensation. Trying to use a transmission line for reactive compensation of the fundamental is different than trying to use a transmission line to address (filter?) harmonics, to my way of thinking. I haven't given much thought to the latter and don't feel I could comment on that without more information about what the system looks like and what you are trying to accomplish.

=====================================
(2B)+(2B)' ?

### RE: VAR compensator by using transmission cable

A VAR compensator typically adds in steps of compensation to keep the power line power factor within the desired limits.
You may find it difficult to vary the reactance of the transmission line in steps.
Other than that, it is what it is.
Your VAR compensator will compensate for load reactance as well as compensate for the transmission cable reactance.

Bill
--------------------
"Why not the best?"
Jimmy Carter

(OP)

### RE: VAR compensator by using transmission cable

Just as the line resistance and line reactance are fixed values (neglecting temperature changes) the line capacitance is a fixed value.
The line capacitance can not be ignored in your design just because it is a fixed value.
You should evaluate the effect of line capacitance on voltage rise when the line is lightly loaded.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

#### Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

#### Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!