If I understand it correctly, curvature in a region of spacetime is due to concentration of energy and momentum in that region. If I further understand things (I don't) a gravitational wave is a transient, radiating region of curvature in spacetime.
Ignoring for the moment the absurdly small curvature caused by charging even the largest capacitor, I believe it is correct to say that a charged capacitor, which locally stores energy, curves spacetime.
Now presume that we have a device that can detect such small curvature, a distance d away from our capacitor. If we charge and discharge that capacitor, will the detector detect transient changes in the gravitational field? Is that the same as saying it is detecting a gravitational wave?