By hvhipot 
1. Flashing phenomenon of series resonance test device
When destructive discharge occurs along the surface of a solid insulator in a gas or liquid medium, it is called flashover. The flashover phenomenon refers to the breakdown voltage discharge along the surface of a solid insulator when the gas or liquid medium around the insulator is damaged. The voltage at which flashover occurs during discharge is called flashover voltage. After the insulator flashover, the voltage between the electrodes quickly drops to zero or approaches zero. Sparks or arcs in the flashover channel can cause local overheating of the insulation surface, damaging the surface insulation.
The common flashover occurs at the interface between gas and solid dielectric, and the destructive discharge along the surface of the insulator string is called flashover. The term “flashover” is used for discharge phenomena under special conditions.
2. Discharge phenomenon of series resonance test device
The discharge phenomenon is a general concept, which generally refers to the jumping phenomenon of insulating materials from an insulating state to a conductive state under the action of an electric field. This jumping phenomenon may occur in the form of “penetration” between electrodes. That is to say, the insulation material is completely short circuited and damaged. At this point, the voltage between the electrodes rapidly drops to extremely low or close to zero, which is called destructive discharge. Jumping phenomenon may also occur in local areas between electrodes, making the insulating material a part of it. When short circuited, the remaining parts still have good insulation performance, and the voltage between the electrodes can still maintain a certain value, which is called partial discharge.
Destructive discharge and partial discharge can be used for all dielectrics and their combinations, however, discharge occurs in different dielectrics and their combinations, and has a special name. In gas or liquid media, destructive discharge between electrodes is called spark discharge. For example, the destructive discharge between the air gap and the oil gap should be spark discharge.
When a destructive discharge occurs in a solid dielectric, it is called breakdown. When breakdown occurs, traces will be left in the solid dielectric, resulting in a loss of insulation performance of the solid dielectric. For example, if the insulation cardboard breaks, a hole will be left on the cardboard.