H - Electricity – 02 – H
Patent
H - Electricity
02
H
317/6
H02H 5/04 (2006.01) H02H 9/04 (2006.01)
Patent
CA 1256937
Case 2858 OVERVOLTAGE PROTECTION SYSTEM ABSTRACT OF THE DISCLOSURE In a system having a bus to which apparatus is connected that might be damaged by overvoltage and in which overvoltage protection is provided by a plurality of zinc oxide varistors connected in series in a column and the column connected between the bus and a reference source, means are provided to protect the varistors from damage caused by excessive temperature due to a large current flow through them. At least one temperature sensor is mounted on one of the varistors to sense when a safety tripping temperature is reached, and responsive to the temperature being reached a relay operates to reduce the voltage on the bus. The voltage on the bus may be reduced to zero to permit the varistors to cool, or if the voltage on the bus can be lowered somewhat by, say, the disconnection of a capacitor bank, this may be done and a second temperature sensor used to sense a protective thermal runaway temperature. In response to this temperature being reached a relay is operated to disconnect the bus and reduce the voltage to zero. Normal operation may be restored when the sensed temperature falls below the safety tripping temperature. In addition, to protect against very rapidly increasing overvoltages, the current flow is monitored and a representation of the current flow, when the current flow is in excess of a threshold, is integrated to give a representation of incremental energy. When the integrated value reaches a first preset level a relay operates to reduce the voltage on the bus. The voltage on the bus may be reduced to zero to permit the varistors to cool, or it may be lowered somewhat and a second preset level provided. In response to the second preset level being reached a relay operates to reduce the voltage on the bus to zero and permit the varistors to cool.
478909
Canadian General Electric Company Limited
Eckersley Raymond A.
LandOfFree
Zinc oxide stack overvoltage protection against temperature... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Zinc oxide stack overvoltage protection against temperature..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Zinc oxide stack overvoltage protection against temperature... will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1300572