What causes of voltage runaway in series LC resonant circuit?

AI Thread Summary
Voltage runaway in a series LC resonant circuit occurs due to the exponential rise in voltage, primarily influenced by the reactance of the inductor and the resistance present in the circuit. The phenomenon can be exacerbated by factors such as distributed capacitance acting as a voltage multiplier and impedance mismatches causing voltage wave reflections. While this effect is often observed in simulators without resistance, real-world circuits can also experience similar voltage magnification, especially when subjected to external excitation like radio signals. Instances of overvoltage can lead to significant damage, as demonstrated in a high voltage electrical substation scenario where an isolated section was excited, resulting in component failure. Understanding these dynamics is crucial for preventing damage in both simulated and actual circuits.
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I'm trying to understand why the voltage in a series LC resonant circuit exponentially rises?

Can anyone explain exactly what happens that creates the effect?

I've been wonding if it the distributed capacitance of L becomes a voltage multiplier, or if it is a voltage wave reflection from a imperfectly matched impedance?
 
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This only happens in simulators and only if you specify a circuit with no resistance in it.

Real series tuned circuits have some resistance.

The voltage magnification is equal to the ratio of XL / R (where XL is the reactance of the inductor) and this value is reached almost instantly.
 
Death to all uncontrolled simulators!
They have a lot to answer for.
 
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I wouldn't exactly say this can only happen in simulators - a tuned LC Ckt with external excitation ( like a radio signal) can easily generate enough V to damage the components. Had this happen once in a High Voltage Electrical substation where a parallel feed (not electrically connected) was able to excite an isolated portion of the substation - to Overvoltage condition.

When the isolated section ( now damaged by overvoltage) was re energized the result was - well - interesting...
 
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