# resonance by dc current?

#### tornedoar

Joined Oct 31, 2019
9
hallo
everyone knows that resonance can be made by AC current because it has frequency but how is it made by DC current? I read a lot of papers that say it is possible, special to make an HVDC circuit breaker so could anyone explain it to me? it would be better with equations

#### SamR

Joined Mar 19, 2019
3,180
By square wave or pulsing?

#### MisterBill2

Joined Jan 23, 2018
8,213
hallo
everyone knows that resonance can be made by AC current because it has frequency but how is it made by DC current? I read a lot of papers that say it is possible, special to make an HVDC circuit breaker so could anyone explain it to me? it would be better with equations
Now there is a question here in what is the TS even talking about???
For starters, resonance is a condition with reactances transferring energy back and forth at a specific frequency. How does that relate to a high voltage DC circuit breaker?
The paper in the link is discussing the use of resonant circuits to reduce the effect of transmission line reactances during opening the circuit because of fault currents. So what is resonant is the cancelling network.
Thus the resonance is not happening with DC, it is happening with a very abrupt change in DC current. and the change in current is a form of AC.

Last edited:

#### nsaspook

Joined Aug 27, 2009
8,158
You transform the DC energy into a AC component with the act of interrupting the steady state DC current flow.
The mechanical resonance DC circuit breaker produces
artificial zero current by superposing an oscillating current on
the DC current. To achieve the artificial zero current crossing,
an LC series resonance circuit is put in parallel with the
interrupter (can be conventional AC breaker) as it is shown in
Fig. 3.
The LC circuit provides a storage source for the needed localized AC current for zero-crossing arc suppression across the breaker contacts.

To the OP, your link has all the required equations and explanations to understand the generation of resonance in these types of circuits.

What happens when DC contracts arc @70KV because of a contact closure failure.