| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 400052 | International Journal of Electrical Power & Energy Systems | 2011 | 6 Pages |
Power networks contain capacitances and inductances that can saturate, presenting opportunities for ferroresonance to occur. Most power equipment is designed through linear theory but ferromagnetic materials are highly non-linear and when they resonate, the non-linearity produces currents and voltages that are larger than usual. Ferroresonance is a complex, non-linear electrical phenomenon. It can cause dielectric and thermal problems through overvoltage, an intrinsic phenomenon present in all networks. A network dynamic response to lightning and switching will be energy storage and release. The transfer of energy will propagate an overvoltage through the network and damage substation equipment when lightning strikes near the substation. Application of conventional mathematics is inappropriate to ferroresonance study in which actual events are simulated. Lightning strikes that occurred near a substation and that led to explosion of CVTs have been reported, so this study investigates the effect of a lightning strike on a tower with a 132 kV Capacitor Voltage Transformer (CVT). Alternative Transient Program (ATP) was used for the simulation which duplicated the lightning-strike effect that causes a CVT to explode.
► A lightning strike can cause ferroresonance in a CVT. ► The most severely affected side of the CVT is the primary side. ► Presently mitigation of ferroresonance is by using spark gap. ► The use of spark gap does not effectively mitigate ferroresonance. ► A new design is proposed for the spark gap to be in parallel with the resistor and in series with the capacitor.
