Common use of Failure Protection for High-Voltage Interrupting Clause in Contracts

Failure Protection for High-Voltage Interrupting. Devices (HVIs) 1.5.1. Provisions shall be made to clear the fault in case the HVI fails to isolate the fault. The requirements for HVI failure protection vary depending on the maximum permissible fault duration and the location of the connection on the transmission system. Some portions of the transmission system are designed and operated to more stringent requirements to avoid adversely affecting neighbouring transmission systems. 1.5.2. In general, the transmission system will require the HVI failure protection to be achieved by using remote or transfer trip circuits. 1.5.3. In portions of the transmission system having less stringent requirements, the HVI failure protection may be achieved by opening the motor-operated disconnect switch. If the disconnect switch experiences a flashover, the line protection at the transmission station(s) shall operate to isolate the fault. 1.5.4. Automatic ground switches are not acceptable for any new installations for triggering line protection operation following the failure of a HVI. 1.5.5. When circuit switchers are used, the interrupter and disconnect switch shall operate independently. Protections that trip the interrupter shall simultaneously initiate opening of the disconnect switch. 1.5.6. The DC voltage supplied to the interrupter and disconnect switch shall be fed from separately fused and monitored DC supplies: that is, by two (2) DC cables to the control cabinet.

Failure Protection for High-Voltage Interrupting. Devices (HVIs) 1.5.1. Provisions shall be made to clear the fault in case the HVI fails to isolate the fault. The requirements for HVI failure protection vary depending on the maximum permissible fault duration and the location of the connection on the transmission system. Some portions of the transmission system are designed and operated to more stringent requirements to avoid adversely affecting neighbouring transmission systems. 1.5.2. In general, the transmission system will require the The HVI failure protection to be achieved by using will initiate remote or transfer trip circuitscircuits and opening of the motor-operated disconnection switch unless otherwise prescribed the Transmitter. 1.5.3. In portions of the transmission system having less stringent requirements, the HVI failure protection may be achieved by opening the motor-operated disconnect switch. If the disconnect switch experiences a flashover, the line protection at the transmission station(s) shall operate to isolate the fault. 1.5.4. Automatic ground switches are not acceptable for any new installations for triggering line protection operation following the failure of a HVIoperation. 1.5.5. When circuit switchers are used, the interrupter and disconnect switch shall operate independently. Protections that trip the interrupter shall simultaneously initiate opening of the disconnect switch. 1.5.6. The DC voltage supplied to the interrupter and disconnect switch shall be fed from separately fused and monitored DC supplies: that is, by two (2) DC cables to the control cabinet.