Potline open circuit protection

Abstract

A potline open circuit can be a dangerous and catastrophic event. It results in a high power DC arc, which can not extinguish itself unless the conversion substation is tripped. It can escalate into an explosion: the arc energy can injure any operators in the vicinity or can damage not only the equipment in question but potentially anything within proximity. The consequences can include freezing of the potline. To manage this risk, the potline must be protected against the danger of open circuit fault. A dedicated system is required to provide effective protection: quick tripping of the rectifying groups is triggered when the open circuit trend is detected. In order to avoid inappropriate potline switching off, the protection system settings must always be optimized according to the operating conditions (potline amperage, potline restart after shutdown, number of stopped pots, etc.). An overview of the potline open circuit phenomena is explained.